Is It The Sugar Or Is It The Food?

Is Fructose Bad For You?

Author: Dr. Stephen Chaney

I don’t usually report on studies done in mice, but this study sheds light on a particularly puzzling question: Why is fructose bad for us?

The studies are clear-cut. High fructose consumption is associated with inflammation, obesity, non-alcoholic liver disease, insulin resistance, type 2 diabetes, kidney disease, increased LDL cholesterol and triglycerides, and heart disease. Based on these associations, fructose appears to be deadly. Why would anyone want to consume it?

Yet fructose is found in virtually every fruit. In fact, fructose, also known as fruit sugar, was first isolated from fruits. Hence the name fructose. Humans have been eating fruits safely for thousands of years. Fruits are very good for us. That raises the question: “If fruits are good for us, how can fructose be bad for us?”.

An important clue can be found by looking at what the food industry has done to the American diet. Because fructose imparts a pleasurable, sweet taste to foods the food industry keeps adding it to more and more foods. As a result, dietary intake of fructose has increased 100-fold over the past two centuries. It has reached the point where fructose now accounts for almost 10% of the caloric intake in the United States.

Is It The Sugar, Or Is It The Food?

Let me expand the discussion by using a couple of graphics I developed for my book, “Slaying The Food Myths”

There Are No Sugar Villains. There Are No Sugar Heroes:

Sugar ComparisonsVirtually all sweeteners are primarily a mixture of fructose and glucose. The graphic on the left compares high fructose corn syrup (the current villain) with other “natural” sweeteners used in foods (our current heroes). High fructose corn syrup ranges from about 40% fructose to 55% fructose. The exact percentage depends on what kind of food product is being made with it.

Honey and coconut sugar are about 45% fructose. Sucrose and grape juice concentrate are around 50% fructose. Apple juice concentrate is around 60% fructose, and agave sugar comes in at a whopping 80% fructose.

In other words, if fructose is the culprit that everyone makes it out to be, “healthy” sugars are no better than high fructose corn syrup. Simply substituting a “healthy” sugar for high fructose corn syrup is unlikely to provide any meaningful benefit.

Is It The Sugar, Or Is The Food?

Apple With Nutrition LabelThis graphic shows us what a nutrition label would look like on a medium apple. I am sure that label is a wake-up call for many of you. The amount of sugar and the percentage of fructose and glucose are about the same as in an 8-ounce soda sweetened with high fructose corn syrup. The same is true for virtually every other fruit you can think of.

Now let me share one more thing you won’t hear from what I refer to as “Dr. Strangelove’s Health Blog” (You probably know the ones I am referring to). Virtually all the studies showing the bad effects of fructose consumption have been done with sodas and sugary junk foods. They haven’t been done with apples.

In fact, virtually every study looking at fruit and vegetable consumption has shown they are incredibly good for us. They lower inflammation and reduce the risk of obesity, diabetes, heart disease, and cancer. And the more the better. One study found that the health benefits of fruit and vegetable consumption topped out at around 10 servings a day.

With this background, you should now fully understand why the question “If fruits are good for us, how can fructose be bad for us?” is so perplexing.

My simplistic explanation has always been that whole foods like fruits have fiber, which slows the absorption of fructose from the intestine. Our bodies were designed to handle fructose in a safe manner when it enters the bloodstream slowly. It is taken up by the liver, converted to glucose, and then slowly metered back into the bloodstream. This provides our brain and other tissues with the glucose they need for energy without blood sugar spikes. This is how fructose is supposed to be metabolized by our bodies.

Sodas and junk foods, on the other hand, have little to slow the absorption of fructose. When lots of fructose enters the bloodstream rapidly, our “safe” metabolic pathways for handling it are overwhelmed, and it is forced into the pathways that are harmful. For example, the “excess” fructose is converted to fat by the liver, which causes inflammation, obesity, fatty liver disease, and triglyceride production.

This is, of course, simply my hypothesis for explaining the different effect of fructose in fruits and sodas. It is based on sound metabolic principles, but it is far from proven. That is why I found a recent study (C. Jang et al, Cell Metabolism, 27: 351-361, 2018) so interesting. It provides a metabolic rationale for my hypothesis.

How Was The Study Done?

Mice were fed a 1:1 mixture of fructose and glucose at doses that approximated the ranges of typical human fructose consumption. The fructose was isotopically labeled so that fructose and its metabolites could be identified by LC-MS (liquid chromatography – mass spectrometry). After feeding the mice the labeled fructose, the investigator measured the amount of fructose and its metabolites in various organs and in the portal vein, which transports sugars from the intestine to the liver for additional metabolism before they enter the bloodstream.

Is Fructose Bad For You?

intestine & liverThe first surprise was that most of the fructose was metabolized by the intestinal mucosal cells that line the small intestine rather than the liver. Previous reports had assumed that fructose was primarily metabolized by the liver because that was where most of the bad effects of fructose metabolism had been observed.

These investigators observed that fructose was primarily converted to glucose and small molecular weight metabolites by the intestinal mucosal cells before being released into the portal vein, where they were transported to the liver. However, there was a strong dose response effect.

  • At low fructose doses, 90% of fructose was metabolized by intestinal mucosal cells before being released to the liver.
  • At high fructose doses, only 70% of fructose was metabolized by intestinal mucosal cells.
  • That means at high fructose doses the amount of fructose reaching the liver unchanged increases from 10% to 30%. That is a 3-fold increase!

The authors concluded:

  • “Based on these findings, we propose that the small intestine shields the liver from fructose and that excessive doses of fructose overwhelm the small intestine, spilling over to the liver where they cause toxicity.”
  • “A key difference between the health effects of fiber-rich fruits (and perhaps even fiber-rich prepared foods) and juices/sodas is their rate of intestinal fructose release.”
  • “It is likely that the appearance rate of free fructose in the small intestine plays a critical role in dictating its metabolic fate. Like the lower doses in our experiments, a slower rate of fructose appearance will result in more complete intestinal clearance, whereas higher doses and faster rates result in fructose overflow to the liver.”

This study needs to be confirmed, and the mechanism may be entirely different in humans. However, whether mechanism is the same in mice and humans is immaterial. We already know that fructose in sodas and junk foods exerts a very different effect on our health than fructose in fruits and other fiber-containing foods.

Despite what Dr. Strangelove tells you, fructose is not bad for you. It isn’t the problem. It is sodas and junk foods containing high-fructose corn syrup that are the problem. And substituting other sugars for high-fructose corn syrup doesn’t make them any better. As I showed you above, the so called “healthy” sugars are chemically and biologically indistinguishable from high-fructose corn syrup.

The Bottom Line

Previous studies have clearly shown that fructose in sodas and junk foods is bad for us, while fructose in fruits is good for us. A recent study in mice provides a metabolic explanation for this difference. The study found:

  • At low fructose doses, 90% of fructose was metabolized by intestinal mucosal cells before being released to the liver.
  • At high fructose doses, only 70% of fructose was metabolized by intestinal mucosal cells.
  • That means at high fructose doses the amount of fructose reaching the liver unchanged increases from 10% to 30%. That is a 3-fold increase!

The authors concluded:

  • “Based on these findings, we propose that the small intestine shields the liver from fructose and that excessive doses of fructose overwhelm the small intestine, spilling over to the liver where they cause toxicity.”
  • “A key difference between the health effects of fiber-rich fruits (and perhaps even fiber-rich prepared foods) and juices/sodas is their rate of intestinal fructose release.”
  • “It is likely that the appearance rate of free fructose in the small intestine plays a critical role in dictating its metabolic fate. Like the lower doses in our experiments, a slower rate of fructose appearance will result in more complete intestinal clearance, whereas higher doses and faster rates result in fructose overflow to the liver.”

This study needs to be confirmed, and the mechanism may be entirely different in humans. However, whether mechanism is the same in mice and humans is immaterial. We already know that fructose in sodas and junk foods exerts a very different effect on our health than fructose in fruits and other fiber-containing foods.

Despite what Dr. Strangelove tells you, fructose is not bad for you. It isn’t the problem. It is sodas and junk foods containing high-fructose corn syrup that are the problem. And substituting other sugars for high-fructose corn syrup doesn’t make them any better. As I showed you above, the so called “healthy” sugars are chemically and biologically indistinguishable from high-fructose corn syrup.

For more details, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Do Whole Grains Reduce Inflammation?

Are Low Carb Diets Healthy Long Term?

Author: Dr. Stephen Chaney 

InflammationInflammation is a bit like Dr. Jekyll and Mr. Hyde. Acute inflammation plays a valuable role in our immune response. But chronic inflammation is a scourge. Chronic inflammation:

  • Is a key component of all the “itis” diseases.
  • Can lead to autoimmune diseases.
  • Is thought to play an important role in heart disease.
  • Is associated with many other diseases, such as diabetes, cancer, Alzheimer’s disease, and inflammatory bowel diseases (IBS).

While there are many causes of chronic inflammation, diet plays an important role. In a previous issue of “Health Tips From the Professor” I have described how an anti-inflammatory diet can quell the fires of chronic inflammation.

Fiber from unprocessed plant foods is a key component of an anti-inflammatory diet. But are all plant fibers equally effective at reducing inflammation? Here is what we know:

  • Fiber from whole grains, vegetables, and fruits have different chemical and physical characteristics and support the growth of different species of friendly bacteria in our intestines.
  • Previous studies have shown that higher intakes of dietary fiber are associated with lower risk of heart disease.
    • Studies have suggested that fiber from whole grains may be more effective than fiber from fruits and vegetables at reducing heart disease risk.
  • Chronic inflammation is highly associated with the development of heart disease. This has led to the hypothesis that fiber from whole grains may be more effective than other plant fibers at reducing chronic inflammation.
    • Some studies have supported this hypothesis, but they have all been done with middle-aged participants, not with elderly participants who characteristically have higher levels of inflammation.

The study (R Shivakoti et al, JAMA Network Open, 5(3): e225012, 2022) I will describe today was designed to:

  • Test the hypothesis that whole grain fiber is more effective than vegetable or fruit fiber at reducing inflammation.
  • Determine how important reducing inflammation is at reducing the risk of heart disease.
  • Extending these findings to an older population group.

How Was The Study Done?

Clinical StudyThe data for this study was obtained from the Cardiovascular Health Study (CHS), a study designed to characterize factors influencing cardiovascular health in American adults aged 65 years or older. This study analyzed data from 4,125 participants (40% men, 95% white) who enrolled in the CHS study from 1989 to 1990.

These participants did not have heart disease at the time they were enrolled in the study. They had an average age of 72.6 at the beginning of the study and were followed for an average of 11.9 years. During that time 1,941 (47%) of them developed heart disease.

When the participants were enrolled in the study:

  • A food frequency questionnaire was administered to them by a trained dietitian to assess their long-term usual dietary intake. This information was used to assess:
    • Their total fiber intake and…
    • Their fiber intake from various dietary sources (whole grains, vegetables, and fruits).
  • Fasting blood samples were collected and used to analyze various markers of inflammation.

A follow-up via phone was conducted every 6 months to track an initial diagnosis of cardiovascular disease.

At the end of the study, the investigators analyzed:

  • The effect of total fiber and fiber from different food sources on the risk of developing heart disease.
  • The effect of total fiber and fiber from different food sources on inflammatory markers in the blood.
  • The extent to which decreased inflammation could explain the effect of whole grain fiber on reducing heart disease.

Do Whole Grains Reduce Inflammation?

With respect to inflammation:

  • Increased intake of total fiber was associated with healthier levels of the inflammatory markers CRP, IL-1RA, and sCD163.
    • Increased intake of fiber from whole grains was associated with healthier levels of the inflammatory markers CRP, IL-6, and IL-1RA.
    • Increased intake of vegetable fiber was not significantly associated with healthier levels of any inflammatory marker.
    • Increased intake of fiber from fruits was associated with healthier levels of the inflammatory marker sCD163.

With respect to cardiovascular disease:

  • Every 5g/day increase in total fiber decreased the risk of heart disease by 5%.
    • Every 5g/day increase in fiber from whole grains decreased the risk of heart disease by 14%.
    • Increased intake of fiber from vegetables and fruits did not have a statistically significant effect on the risk of heart disease.

Finally, when the investigators did a statistical analysis to determine to extent to which the effect of whole grain fiber on inflammation, could explain its effect on heart disease, they concluded:

  • The effect of whole grain fiber on inflammation could explain only about 16% of its effect on heart disease.

In the words of the authors, “In this prospective study of older adults, higher intakes of total fiber were associated with lower levels of various inflammatory markers, and this inverse association was primarily due to cereal fiber intake. Vegetable and fruit fiber intakes were not consistently associated with lower levels of inflammatory markers. These results suggest that specifically cereal fibers might be more effective in reducing systemic infection, which will need to be tested in interventional studies of specific populations.

In addition, cereal fiber was associated with a lower risk of CVD, although inflammation mediated less than 20% of the observed inverse association between cereal fiber and CVD. This suggests that the association of cereal fiber is primarily due to factors … other than systemic inflammation.”

Note: This conclusion underplays the role of fruit fiber in reducing inflammation. The statement is correct in saying only whole grain fiber reduces the inflammatory markers CRP, IL-6, and IL-1RA. However, both total fiber and fruit fiber increase the anti-inflammatory marker sCD163. That is why I chose to use the term “healthier levels” rather than lower or higher levels when describing the effects of whole grain and fruit fibers on markers of inflammation.

What Does This Study Mean For You?

confusion#1: The biggest takeaway from this study is that whole grains are good for you.

  • This study shows that whole grain fiber decreases our risk of developing heart disease.
    • This is fully consistent with multiple previous studies showing that whole grains decrease the risk of heart disease.
    • Previous studies have also shown that whole grains reduce the risk of cancer and diabetes.
  • This study also suggests that whole grain fiber reduces chronic inflammation.

There are also some takeaways from this and previous studies that may not be so obvious.

#2: Fiber has many important benefits beyond its effect on inflammation. For example:

  • This study concluded that the reduction in inflammation only explained a small part of the beneficial effect of whole grain fiber on reducing heart disease risk.
  • That is because whole grain fiber also:
    • Feeds friendly bacteria that improve gut function.
    • Provides satiety that can result in reduced fat and calorie intake.
    • Binds cholesterol, which improves blood cholesterol level.
    • Slows the rate at which dietary sugar enters the bloodstream, which improves blood sugar control.

#3: Whole plant foods have many benefits beyond their fiber content.

  • This study concluded that whole grain fiber was more beneficial than fiber from fruits and vegetables at reducing inflammation and reducing the risk of heart disease.
  • Previous studies have also shown that fruit and vegetables significantly decrease the risk of heart disease, stroke, and cancer.
  • That is because whole grains and unprocessed fruits and vegetables:
    • Displace sugar, refined flour, and highly processed foods from the diet.
    • Have a lower caloric density than processed foods, making it easier to achieve a healthy weight.
    • Provide nutrients and phytonutrients not found in processed foods.
    • Support a wide variety of healthy gut bacteria.

Are Low Carb Diets Healthy Long Term?

low carb dietconfusionWhen you consider all the benefits of whole grains, fresh fruits, and vegetables, it brings us to the final take home message.

#4: Despite what Dr. Strangelove has told you, low-carb diets may not be healthy long term.

  • There are no long-term (10 or 20-year) studies of low-carb diets. We simply have no evidence to support the claim that they are healthy long term.
  • Most low-carb diets eliminate or severely limit fruits and whole grains. Considering the many health benefits they provide, it is unlikely that any diet that restricts them is healthy long term.

The Bottom Line 

A recent study looked at the effect of plant fiber on inflammation and on heart disease.

With respect to inflammation the study found:

  • Increased intake of total fiber was associated with healthier levels of the inflammatory markers CRP, IL-1RA, and sCD163.
    • Increased intake of fiber from whole grains was associated with healthier levels of the inflammatory markers CRP, IL-6, and IL-1RA.
    • Increased intake of vegetable fiber was not significantly associated with healthier levels of any inflammatory marker.
    • Increased intake of fiber from fruits was associated with healthier levels of the inflammatory marker sCD163.

With respect to cardiovascular disease:

  • Every 5g/day increase in total fiber decreased the risk of heart disease by 5%.
  • Every 5g/day increase in fiber from whole grains decreased the risk of heart disease by 14%.
    1. The biggest takeaway from this study is that whole grains are good for you.

 Other takeaways from this and previous studies are:

2) Fiber has many important benefits beyond its effect on inflammation.

3) Whole plant foods have many benefits beyond their fiber content.

4) Despite what Dr. Strangelove has told you, low-carb diets may not be healthy long term.

For more details on this study and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Does Time-Restricted Eating Have A Downside?

Are The Benefits Of Time-Restricted Eating An Illusion?

 Author: Dr. Stephen Chaney

intermittent fastingWeight loss is difficult. If you are like most American adults, you have tried at least 5 or 6 diets by the time you are 50, and all of them have failed. Or maybe you have found a diet that works reasonably well at helping you lose weight, but it’s difficult to stick with. And you worry that it may not be healthy long-term.

But hope springs eternal, and there are always new diets to try. One of the newer diet fads is something called intermittent fasting. The most popular form of intermittent fasting (because it is the easiest to follow) is something called time-restricted eating.

The concept is simple. You don’t change what you are eating. Instead, you restrict the time during which you are eating those foods. Typically, you restrict your time of eating to 8 hours a day and abstain from all food the rest of the day. Hence, the term “time-restricted eating”.

I won’t go into the supposed benefits of time-restricted eating. You have probably heard those already from advocates of this form of eating. But you may be wondering if those benefits are true and whether time-restricted eating has any drawbacks.

Fortunately, a recent study (T Moro et al, Medicine and Science In Sports & Exercise, 53, 2577-2585, 2021) answers those questions. It put a group of athletes on either a control diet or a time-restricted diet for an entire year and looked at the relative benefits and drawbacks of both diets.

How Was This Study Done?

Clinical StudyThis study recruited 19 healthy, resistance-trained males (average age = 29, average weight = 185 pounds) for the study. All the subjects had at least 5 continuous years of resistance training, no steroid use, and no known medical conditions.

The subjects completed a 7-day food diary prior to the study, at the end of 2 months, and at the end of 12 months. The participants were instructed not to change their usual caloric intake or diet composition. In addition, each participant received a personalized diet protocol based on the analysis of their food diary at baseline.

The results from the first two months have previously been reported (T Moro et al, Journal of Translational Research, 14: 290, 2016). This report covers the subsequent 10 months.

During the first two months, the participants were contacted weekly by a dietitian to ensure adherence to the diet. During the interviews, the dietitian asked questions about meal timing and composition, appetite, and any difficulties in maintaining the diet protocol. When necessary, the dietitian gave advice to improve adherence to the diet. During the subsequent 10 months, the participants were contacted less frequently, and the interviews were shorter.

The participants were divided into two groups. The selection was random except that the two groups were matched with respect to caloric intake at baseline (~2,900 calories/day).

The ND (normal meal distribution) group ate their meals over a 12-hour period, with meals at ~8AM, 1 PM, and 8 PM. The distribution of calories for this group was 25%, 40%, and 35% over the three meals.

The TRE (time-restricted eating) group ate their meals over an 8-hour period, with meals at ~1PM, 4 PM, and 8 PM. The distribution of calories for this group was 40%, 25%, and 35% over the three meals.

The training regimen consisted of strength training specifically designed to increase muscle mass. A standardized 3-times per week training regimen was established during the first two months of supervised training. The participants continued the same training regimen on their own for the next 10 months. Workouts were performed between 4 and 6 PM to fall within the eating window for both groups.

Finally, tests for inflammatory markers, cholesterol & other blood lipids, blood sugar control, hormones, body composition, and strength were performed before the program started, at 2 months, and again at 12 months.

What Are The Benefits Of Time Restricted Eating?

thumbs upWhen the investigators looked at health outcomes at the end of 12 months:

  • Inflammatory markers were significantly reduced in the TRE (time-restricted eating) group compared to the ND (normal meal distribution) group.
  • Blood sugar control was significantly improved in the TRE group compared to the ND group.
  • Lipid profiles were significantly improved in the TRE group compared to the ND group.

These results are consistent with the findings of earlier short-term studies on the benefits of time restricted eating.

The authors concluded. “Our results suggest that long-term time-restricted eating in combination with a resistance training program is feasible, safe, and effective in reducing inflammatory markers and risk factors.”

At this point you are probably thinking, “It sounds like everything I have heard about time-restricted eating is true. I can’t wait to get started.”

What Causes The Benefits Of Time-Restricted Eating?

SkepticBefore you jump on the time restricted eating bandwagon, let’s look more closely and ask what caused these apparent health benefits.

When the investigators looked at changes in caloric intake over the 12-month period:

  • The TRE group spontaneously decreased their total caloric intake by 6.4% in spite of being told not to change their diet.
    • The decrease in caloric intake was driven by a decrease in both carbohydrate and fat intake, while protein intake remained constant.
    • Most of this change occurred between 2 and 12 months when they were no longer being closely supervised by dietitians.
  • In contrast, caloric intake and macronutrient intake did not change significantly for the ND group.

The reason for the decrease in caloric intake is not known.

  • If you follow social media or blogs about time-restricted eating, you have been given some scientific-sounding mumbo-jumbo about how the 16 hours of fasting changes your metabolism and/or reduces your appetite. However, this is speculation. There is scant evidence for it.
  • A more likely explanation is that when you restrict the time you allow yourself to eat, you naturally eat less without thinking about it. You are simply less hungry when the second and third meals roll around. [This may explain why even these highly disciplined athletes required weekly coaching by dietitians to keep their caloric intake constant.]

And when the investigators looked at changes in body weight over the 12-month period:

  • The TRE group lost 3.4% of their body weight.
    • Most of that weight loss was due to a decrease in fat mass, but there was also a loss of muscle mass.
  • In contrast the ND group increased their total body weight by 3.4%.
    • In other words, at the end of 12 months the difference between the TRE and ND groups amounted to almost 7% of their body weight. This difference was highly significant.
    • Most of the increase in body weight in the ND group was due to a 2.9% increase in muscle mass.

These results are also consistent with the findings of earlier studies of time-restricted eating.

The observed decrease in body weight and fat mass is important because whenever you decrease body weight and fat mass, you:

  • Reduce inflammatory markers.
  • Improve blood sugar control.
  • Improve lipid profiles.

In the words of the authors, “…it is plausible that the caloric reduction observed in the TRE group may have contributed to the reductions in body mass and additional health benefits…”

Of course, that still sounds pretty good. Who wouldn’t want to lose weight and get healthier? But are the weight reduction and health benefits unique to time-restricted eating? That is the claim of those who promote this diet.

But is it true? To answer that question, we need to take a broader view of popular diets. We need to ask, “Is something special about time-restricted eating, or would other restrictive diets give similar results?”

Are The Benefits Of Time-Restricted Eating An Illusion?

The TruthThere are two diet truths that nobody is talking about:

1) Forget the metabolic mumbo-jumbo. The primary reason restrictive diets cause you to lose weight is that you unconsciously eat less while you are on these diets.

For time-restricted eating, you eat less because you have restricted the time when you can eat. With other restrictive diets, you have restricted the foods you can eat. The reason why that causes you to eat less is more subtle. I call it the “Bagels and Cream Cheese Effect”.

    • When you go on a low-fat diet, it sounds great to say you can eat all the bagels you want. But without the cream cheese, bagels become boring, and you eat less.
    • When you go on a low-carb diet, it sounds great to say you can eat all the cream cheese you want. But without the bagels, cream cheese becomes boring, and you eat less.

2) The proponents of fad diets make them look good by comparing them to the typical American diet. Anything is better than the American diet. However, when you make the comparisons based on the reduction in caloric intake or the amount of weight lost, the health benefits of popular diets are virtually identical. For example:

    • When you compare the Atkins diet and other low carb diets with the typical American diet, inflammation is lower on the low carb diets. However, one recent study compared people on the Atkins diet with people who had lost an equal amount of weight on a balanced diet that included all food groups. Guess what? Inflammation is much higher on the Atkins diet when you compare it to a healthy diet that gives equal weight loss.
    • This study reported that the time-restricted eating group ate less, lost more weight, and had better health parameters than the control group. However, previous studies that compared time-restricted eating with groups that reduced caloric intake to the same extent by simply counting calories have found the two groups had identical weight loss and improvement in health parameters.

In other words, there is nothing magical about time-restricted eating. Any diet that causes you to eat less will give identical results. There are only two questions left:

  1. Can you stick with time-restricted eating long term?

Time-restricted eating is not everyone’s cup of tea. But this study suggests that if you can stick with it better than with other restrictive diets, you are likely to lose weight and reap some health benefits.

2) Should you stick with time-restricted eating long term?

To answer this question, you need to know whether there are any downsides to time-restricted eating.

Does Time-Restricted Eating Have A Downside?

thumbs down symbolOf course, most people would consider weight loss and an improvement in health parameters as a definite plus. It’s all good. Or is it? Does time-restricted eating have any downsides? This study identified two potential downsides:

1) Decreased anabolic hormones.

    • Anabolic hormones (hormones that stimulate an increase in muscle mass) were decreased in the TRE group. Specifically:
      • Testosterone was decreased by 17% at the end of 12 months in the TRE group.
      • Insulin-like growth factor-1 (IGF-1) was decreased by 14% in the TRE group.
    • Both anabolic hormone levels were unchanged in the ND group.

2) Decreased muscle mass. Between months 2 and 12:

    • Muscle mass was decreased by 2.3% in TRE group and increased by 2.9% in the ND group.
    • The cross-sectional area of arm and thigh muscles was decreased by an average of 4.3% in the TRE group and increased by an average of 8.5% in the ND group.

In the words of the authors, “With our results, we confirmed that a long-term TRE protocol could impair the ability of maintaining muscle mass, possibly because of a reduction in caloric intake and a direct effect of fasting on the production of anabolic hormones.”

That is putting it mildly. The participants in this study were engaged in a rigorous 3-times/week strength training program specifically designed to increase muscle mass and were consuming over 100 grams of protein a day. So, a continuous increase in muscle mass and cross-sectional area would be expected. This was seen in the ND group but not in the TRE group, which actually lost muscle mass. The average “Joe” or “Jane” would likely lose even more muscle on this diet.

And continuous, long-term loss of muscle mass has significant health consequences including:

  • Decreased metabolic rate, which makes it more difficult to maintain a healthy weight.
  • Decreased insulin sensitivity, which increases the risk of diabetes.
  • Increased risk of osteoporosis.
  • Muscle weakness, which increases the risk of falling.

Dr. Paoli, the lead scientist on this study, was quoted as saying, “The main take home message is that there are pros and cons to prolonged time-restricted eating. Although time-restricted eating may produce some physiological advantages, it is not a miracle as often suggested in social media posts.”

The Bottom Line 

A recent study looked at the pros and cons of following a time-restricted eating (TRE) diet compared to a diet with normal meal distribution (ND) for 12 months.

  • The TRE group had reduced inflammation, better blood sugar control, and better lipid profiles than the ND group.

However, the improved health parameters were not caused by some magical metabolic changes due to fasting.

  • The TRE group unconsciously reduced their caloric intake and lost weight compared to the ND group. And any time you lose weight, you get reduced inflammation, better blood sugar control, and better lipid profiles.

In the words of the authors, “…it is plausible that the caloric reduction observed in the TRE group may have contributed to the reductions in body mass and additional health benefits…”

And there is nothing unique about time-restricted eating.

  • Any restrictive diet is likely to give similar results. (For more details, read the article above.)

Finally, there were some significant downsides to time-restricted eating.

  • The TRE group had a reduction in anabolic hormones and lost muscle mass.

In the words of the authors, “With our results, we confirmed that a long-term TRE protocol could impair the ability of maintaining muscle mass, possibly because of a reduction in caloric intake and a direct effect of fasting on the production of anabolic hormones.”

This is putting it mildly. The participants in this study were engaged in a rigorous 3-times/week strength training program specifically designed to increase muscle mass and were consuming over 100 grams of protein a day. They should have gained muscle mass. Instead, they lost it.

Continuous, long-term loss of muscle mass has significant health consequences including:

  • Decreased metabolic rate, which makes it more difficult to maintain a healthy weight.
  • Decreased insulin sensitivity, which increases the risk of diabetes.
  • Increased risk of osteoporosis.
  • Muscle weakness, which increases the risk of falling.

Dr. Paoli, the lead scientist on this study, was quoted as saying, “The main take home message is that there are pros and cons to prolonged time-restricted eating. Although time-restricted eating may produce some physiological advantages, it is not a miracle as often suggested in social media posts.”

For more details read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Can Your Diet Cause You To Lose Your Mind?

What Is A Mind-Healthy Lifestyle? 

Author: Dr. Stephen Chaney

Cognitive-DeclineMost of us look forward to our golden years – that mystical time when we will be free from the workday pressures and have more time to spend with friends and family doing the things we love.

But cognitive decline can cast a dark cloud over those expectations.

  • By the age of 65, 11% of adults suffer from some degree of cognitive impairment.
  • And by the age of 80 the percentage of adults suffering from cognitive impairment has increased to 26-30%, depending on which study you cite.

The results of cognitive decline can be devastating.

  • First you start to lose the cherished memories of a lifetime.
  • Then comes confusion and an inability to perform basic tasks and participate in your favorite activities.
  • Eventually you may reach a stage where you no longer recognize the ones you love.

In short, cognitive decline can rob you of everything that makes you you.

The causes of cognitive decline are complex, but recent studies have pointed to the role of chronic inflammation in cognitive decline. If that is true, it is a good news – bad news situation.

  • The bad news is:
    • Some increase in chronic inflammation appears to be an inevitable consequence of aging.
    • Chronic inflammation can be caused by certain diseases that are beyond our control.
    • Chronic inflammation can be triggered by viral or bacterial infections.
  • The good news is that chronic inflammation is also controlled by your diet and lifestyle. For example, as I said above, chronic inflammation is often triggered by a viral infection, but whether the inflammation is mild or severe is strongly influenced by diet and lifestyle.

In this issue of “Health Tips From the Professor” I share a study (S Charisis et al, Neurology, In Press, November 10, 2021) showing that diets high in inflammatory foods increase the risk of dementia. Then, I answer 3 important questions.

  • Can your diet cause you to lose your mind?
  • What is a mind-healthy diet?
  • What is a mind-healthy lifestyle?

How Was This Study Done?

Clinical StudyThe data for this study were taken from the first three years of the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD), a study designed to look at the effect of diet on dementia and other neuropsychiatric conditions in the Greek population.

There were 1059 participants (40% male, average age = 75 at the beginning of the study) in this study. At the beginning of the study the participants completed a food frequency questionnaire administered by a trained dietitian. The foods were broken down into individual nutrients using the USDA Food Composition tables adapted for foods in the Greek diet.

The diet of each participant was then rated on a 15-point scale ranging from pro-inflammatory to anti-inflammatory based on something called the Diet Inflammation Index (DII).

Simply put, the DII is a validated assessment tool based on the effect of food nutrients on 6 inflammatory biomarkers found in the blood (IL-1β, IL-4, IL-6, IL-10, TNF-α, and CRP). Nutrients that decrease these markers are considered anti-inflammatory. Nutrients that increase these inflammatory biomarkers are considered pro-inflammatory.

For example, anti-inflammatory nutrients include:

  • Carotenoids and flavonoids (found in fruits and vegetables).
  • Omega-3 polyunsaturated fatty acids (found in cold-water fish, walnuts, flaxseeds, and chia seeds).
  • Monounsaturated fatty acids (found in olive, avocado, and peanut oils).
  • Fiber (found in minimally processed plant foods).
  • Antioxidants, most B vitamins, and vitamin D.
  • Magnesium and zinc.
  • Garlic, onions, most herbs & spices.

Pro-inflammatory nutrients include:

  • Refined carbohydrates.
  • Cholesterol.
  • Total fat.
  • Saturated fats.
  • Trans fats.

The participants were followed for 3 years, and all new diagnoses of dementia were recorded. The diagnoses were confirmed by a panel of neurologists and neuropsychologists.

Can Your Diet Cause You To Lose Your Mind?

Forgetful Old ManAs described above, the diet of each participant in the study was rated on a 15-point DII (Diet Inflammatory Index) scale ranging from pro-inflammatory to anti-inflammatory. The association of the DII score of the participant’s diets with the onset of dementia was evaluated in two ways.

  • Each one-point increase from an anti-inflammatory diet to a pro-inflammatory diet was associated with a 21% increase in the risk for dementia.
  • In other words, even small changes in your diet can have a significant impact on your risk of developing dementia.

The investigators then divided the participants into three equal-sized groups based on the DII score of their diets.

  • The group with the highest DII scores were 3 times more likely to develop dementia than the group with the lowest DII scores.
  • In other words, a major change in your diet can have a major effect on your risk of developing dementia.

The authors concluded, “In the present study, higher DII scores (indicating greater pro-inflammatory diet potential) were associated with an increased risk for incident dementia [newly diagnosed dementia]. These findings may avail the development of primary dementia strategies through tailored and precise dietary interventions.”

What Is A Mind-Healthy Diet?

Vegan FoodsThis and other studies show that an anti-inflammatory diet is good for the mind. It helps protect us from cognitive decline and dementia. But what does an anti-inflammatory diet look like?

One hint comes from analyzing the diets of participants in this study:

  • Those with the lowest DII scores (most-anti-inflammatory diets) consumed 20 servings of fruit, 19 servings of vegetables, 4 servings of beans or other legumes, and 11 servings of coffee or tea each week. That’s almost 3 servings of fruit and 3 servings of vegetables every day!
  • Those with the highest DII scores (most pro-inflammatory diets) consumed only half as many fruits, vegetables, and legumes.
  • In short, a diet rich in fruits, vegetables, and legumes is a good start.

I have described anti-inflammatory diets in more detail in a previous issue of “Health Tips From the Professor.” Let me summarize that article briefly.

Anti-inflammatory foods include:

  • Colorful fruits and vegetables.
  • Whole grains.
  • Beans and other legumes.
  • Nuts, olive oil, avocados, and other sources of monounsaturated fats.
  • Fatty fish and other sources of omega-3 fatty acids.
  • Herbs and spices.

Pro-inflammatory foods include:

  • Refined carbohydrates, sodas, and sugary foods.
  • Foods high in saturated fats including fatty and processed meats, butter, and high fat dairy products.
  • Foods high in trans fats.
  • French fries, fried chicken, and other fried foods.
  • Foods you are allergic or sensitive food. For example, gluten containing foods are pro-inflammatory only if you are sensitive to gluten.

If your goal is to reduce chronic inflammation and keep your mind sharp as a tack as you age, you should eat more anti-inflammatory foods and less pro-inflammatory foods.

Of course, we don’t just eat random foods, we follow dietary patterns. It should be apparent from what I have Mediterranean Diet Foodscovered above that whole food, primarily plant-based diets are anti-inflammatory. This is true for diets ranging from vegan through semi-vegetarian, to the Mediterranean, DASH, and MIND diets.

All these diets are anti-inflammatory and likely protect the brain from cognitive decline. However, the best evidence for brain protection is for the Mediterranean, DASH, and MIND diets.

  • The Mediterranean and DASH diets have been shown to prevent cognitive decline in multiple studies.
  • The MIND diet is a combination the Mediterranean and DASH diets that was specifically designed to prevent cognitive decline. It has been shown to cut the risk of developing Alzheimer’s disease in half.

What Is A Mind-Healthy Lifestyle?

Diet is just one aspect of a holistic approach for reducing cognitive decline as we age. Other important factors include:

  • Reduce excess body weight.
  • Exercise regularly.
  • Get adequate sleep.
  • Reduce and/or manage stress.
  • Eliminate smoking and reduce alcohol consumption.
  • Socialize with friends and family who support you. Numerous studies have shown that a strong support network reduces dementia risk in the elderly.
  • Keep your brain active. Work crossword puzzles. Learn new things. An active brain is forced to lay down new neural pathways.

The Bottom Line 

Recent studies have suggested that chronic inflammation increases the risk of cognitive decline and dementia as we age. Some causes of chronic inflammation are beyond our control, but others, such as diet, we can control.

Recently, a precise scoring system called the Diet Inflammatory Index (DII) has been developed. This scoring system allows studies to look at the correlation between the inflammatory potential of the diet and cognitive decline.

A recent study enrolled 1,000 participants with an average age of 75 in a 3-year study to determine the impact of diet on cognitive decline. The association of the DII score of the participant’s diets with the onset of dementia was evaluated in two ways.

  • Each one-point increase from an anti-inflammatory diet to a pro-inflammatory diet was associated with a 21% increase in the risk for dementia.
  • In other words, even small changes in your diet can have a significant impact on your risk of developing dementia.

The investigators then divided the participants into three equal-sized groups based on the DII score of their diets.

  • The group with the highest DII scores were 3 times more likely to develop dementia than the group with the lowest DII scores.
  • In other words, a major change in your diet can have a major effect on your risk of developing dementia.

The authors concluded, “In the present study, higher DII scores (indicating greater pro-inflammatory diet potential) were associated with an increased risk for incident dementia [newly diagnosed dementia]. These findings may avail the development of primary dementia strategies through tailored and precise dietary interventions.”

For more details and a description of mind-healthy diets and a mind-healthy lifestyle read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

What Is An Anti-Inflammatory Diet?

Can Diet Douse The Flames?

Author: Dr. Stephen Chaney

InflammationIf you have arthritis, colitis, bursitis, or any of the other “itis” diseases, you already know that inflammation is the enemy. Chronic, low level inflammation is also a contributing factor to heart disease, cancer, and many other diseases. Clearly, inflammation is a bad actor. It is something we want to avoid.

Obesity and diabetes are two of the biggest contributors to inflammation, but does diet also play a role? With all the anti-inflammation diets circulating on the internet, you would certainly think so. How good is the evidence that certain foods influence inflammation, and what does an anti-inflammatory diet look like?

The Science Behind Anti-Inflammatory Diets

ScientistLet me start by saying that the science behind anti-inflammatory diets is nowhere near as strong as it is for the effect of primarily plant-based diets on heart disease and diabetes. The studies on anti-inflammatory diets are mostly small, short duration studies. However, the biggest problem is that there is no standard way of measuring inflammation.

There are multiple markers of inflammation, and they do not change together. That means that in every study some markers of inflammation are altered, while others are not. There is no consistent pattern from one study to another.

In spite of these methodological difficulties, the studies generally point in the same direction. Let’s start with the strongest evidence and work our way down to the weakest evidence. 

Omega-3 fats are anti-inflammatory (I. Reinders et al, European Journal of Clinical Nutrition, 66: 736-741, 2011). The evidence is strongest for the long chain omega-3s found in fish and fish oil, but the shorter chain omega-3s found in foods like walnuts, flaxseeds, chia seeds and flaxseed oil, soybean oil, and canola oil also appear to be anti-inflammatory. 

Inflammation is directly correlated with glycemic index (L. Qi and F.B. Lu, Current Opinion in Lipidology, 18: 3-8, 2007). This has a couple of important implications.

The most straightforward is that refined carbohydrates and sugars (sodas, pastries, and desserts), which have a high glycemic index, increase inflammation. In contrast, complex carbohydrates (whole grains, most fruits and vegetables) decrease inflammation. No surprise there. The second implication is that it is the glycemic index, not the sugar, that is driving the inflammatory response.

That means we need to look more closely at foods than at sugars. Sodas, pastries and desserts are likely to cause inflammation, but sugar-containing foods with a low glycemic index are unlikely to be inflammatory. 

Fruits and vegetables are anti-inflammatory. This has been shown in multiple studies. At this point most of the research is centered on identifying the nutrients and phytonutrients from fruits and vegetables that are responsible for the reduction in inflammation. I suspect the investigators are hoping to design an anti-inflammatory supplement and make lots of money. I will stick with the fresh fruits and vegetables. 

Saturated fats are inflammatory. At face value, the data on saturated fats appear to be contradictory. Some Fatty Foodsstudies say that saturated fats increase inflammation, while others say they do not. However, similar to my earlier discussion on saturated fats and heart disease), the outcome of the study depends on what the saturated fats are replaced with.

When saturated fats are replaced with refined carbohydrates, sugar and highly processed foods (the standard American low-fat diet), inflammation doesn’t change. This doesn’t mean that a diet high in saturated fat is healthy. It just means that both diets are bad for you. Both are inflammatory.

However, when saturated fat is replaced with omega-3 polyunsaturated fats (J.A. Paniagua et al, Atherosclerosis, 218: 443-450, 2011) or monounsaturated fats (B. Vessby et al, Diabetologia, 44: 312-319, 2001), markers of inflammation decrease. Clearly, saturated fats are not the best fat choice if you wish to keep inflammation in check.

I would be remiss if I did not address the claims by the low-carb diet proponents that saturated fats do not increase inflammation in the context of a low-carb diet. I want to remind you of two things we have discussed previously:

  • The comparisons in those studies are generally with people consuming a diet high in simple carbohydrates and sugars.
  • These studies have mostly been done in the short-term when the participants are losing weight on the low-carb diets. Weight loss decreases inflammation, so the reduction in inflammation on the low-carb diet could be coming from the weight loss.

The one study (M. Miller et al, Journal of the American Dietetic Association, 109: 713-717, 2009) I have found that compares a low-carb diet (the Atkins diet) with a good diet (the Ornish diet, which is a low-fat, lacto-ovo vegetarian diet) during weight maintenance found that the meat based, low-carb Atkins diet caused greater inflammation than the healthy low-fat Ornish diet.

Red meat is probably pro-inflammatory. Most, but not all, studies suggest that red meat consumption is associated with increased inflammation. If it is pro-inflammatory, the inflammation is most likely associated with its saturated fat, its heme iron content, or the advanced glycation end products formed during cooking.

What Is An Anti-Inflammatory Diet?

Colorful fruits and vegetablesAnti-inflammatory diets have become so mainstream that they now appear on many reputable health organization websites such as Harvard Health, WebMD, the Mayo Clinic, and the Cleveland Clinic. Each have slightly different features, but there is a tremendous amount of agreement. 

Foods an anti-inflammatory diet includes: In a nutshell, an anti-inflammatory diet includes fruits and vegetables, whole grains, plant-based proteins (like beans and nuts), fatty fish, and fresh herbs and spices. Specifically, your diet should emphasize:

  • Colorful fruits and vegetables. Not only do they help fight inflammation, but they are a great source of antioxidants and other nutrients important for your health.
  • Whole grains. They have a low glycemic index. They are also a good source of fiber, and fiber helps flush inflammatory toxins out of the body.
  • Beans and other legumes. They should be your primary source of protein. They are high in fiber and contain antioxidants and other anti-inflammatory nutrients.
  • Nuts, olive oil, and avocados. They are good sources of healthy monounsaturated fats, which fight inflammation.
  • Fatty fish. Salmon, tuna, and sardines are all great sources of long chain omega-3 fatty acids, which are fish and fish oilincorporated into our cell membranes. Those long chain omega-3s in cell membranes are, in turn, used to create compounds that are powerful inflammation fighters.

Walnuts, flaxseeds, and chia seeds are good sources of short chain omega-3s. The efficiency of their conversion to long chain omega-3s that can be incorporated into cell membranes is only around 2-5%. If they fight inflammation, it is probably because they replace some of the saturated fats and omega-6 fats you might otherwise be eating.

  • Herbs and spices. They add antioxidants and other phytonutrients that fight inflammation.

Foods an anti-inflammatory diet excludes: In a nutshell, an anti-inflammatory diet should exclude highly processed, overly greasy, or super sweet foods, especially sodas and other sweet drinks. Specifically, your diet should exclude:

  • Refined carbohydrates, sodas and sugary foods. They have a high glycemic index, which is associated with inflammation. They can also lead to weight gain and high blood sugar, both of which cause inflammation.
  • Foods high in saturated fats. This includes fatty and processed meats, butter, and high fat dairy products.
  • Foods high in trans fats. This includes margarine, coffee creamers, and any processed food containing partly hydrogenated vegetable oils. Trans fats are very pro-inflammatory.
  • French fries, fried chicken, and other fried foods. They used to be fried in saturated fat and/or trans fat. Nowadays, they are generally fried in omega-6 vegetable oils. A little omega-6 in the diet is OK, but Americans get too much omega-6 fatty acids in their diet. Most studies show that a high ratio of omega-6 to omega-3 fatty acids is pro-inflammatory.
  • Foods you are allergic or sensitive to. Eating any food that you are sensitive to can cause inflammation. This comes up most often with respect to gluten and dairy because so many people are sensitive to one or both. However, if you are not sensitive to them, there is no reason to exclude whole grain gluten-containing foods or low-fat dairy foods from your diet.

Can Diet Douse The Flames?

FlamesIn case you didn’t notice, the recommendations for an anti-inflammatory diet closely match the other healthy diets I have discussed previously. It should come as no surprise then that both the Mediterranean (L. Gallard, Nutrition in Clinical Practice, 25: 634-640, 2010; L. Schwingshackl and G. Hoffmann, Nutrition Metabolism and Cardiovascular Diseases, 24: 929-939, 2014) and DASH (D.E. King et al, Archives of Internal Medicine, 167: 502-506, 2007) diets are anti-inflammatory.

Vegan and vegetarian diets also appear to be anti-inflammatory as well. The anti-inflammatory nature of these diets undoubtedly contributes to their association with a lower risk of heart disease, diabetes, and cancer.

As for the low-carb diets, the jury is out. There are no long-term studies to support the claims of low-carb proponents that their diets reduce inflammation. The few long-term studies that are available suggest that low-carb diets are only likely to be anti-inflammatory if vegetable proteins and oils replace the animal proteins and fats that are currently recommended.

What does this mean for you if you have severe arthritis or other inflammatory diseases? An anti-inflammatory diet is unlikely to “cure” your symptoms by itself. However, it should definitely be a companion to everything else you are doing to reduce inflammation.

The Bottom Line 

If you have arthritis, colitis, bursitis, or any of the other “itis” diseases, you already know that inflammation is the enemy. Chronic, low level inflammation is also a contributing factor to heart disease, cancer, and many other diseases. Clearly, inflammation is a bad actor. It’s something we want to avoid.

Obesity and diabetes are two of the biggest contributors to inflammation, but does diet also play a role? With all the anti-inflammation diets circulating on the internet, you would certainly think so. In this article I review the evidence that certain foods influence inflammation and describe what an anti-inflammatory diet looks like.

For more details read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Omega-3 Fatty Acids And Brain Health

Is it How Much You Eat, or How Much You Keep?

Author: Dr. Stephen Chaney

 

Brain HealthWhy do some studies conclude that omega-3 fatty acids are essential for a strong mind, a strong heart and will wipe out inflammation – while other studies suggest that they are ineffective? The simple answer is that nobody really knows.

However, in the process of reviewing two recent studies on omega-3 fatty acids and brain health I made an interesting observation that offers a possible explanation for the discrepancies between studies. And if my hypothesis is correct, it suggests that the design of many of the previous studies with omega-3 fatty acids is faulty.

Omega-3 Fatty Acids And Brain Health

The first study (J.K. Virtanen et al, J Am Heart Assoc, 2013, 2:e000305 doi: 10.1161/JAHA.113.000305) looked at the effect of omega-3 fatty acids on brain function in older adults (>65 years old). It concluded that high omega-3 levels were associated with better white matter grade and a 40% reduction in subclinical infarcts (Sorry for the technical jargon – but both of those are good things in terms of brain function for those of us who are getting a bit older).

The second study (C. M. Milte et al, J of Attention Disorders, 2013, doi: 10.1177/1087054713510562) looked at the effect of omega-3 fatty acids on children (ages 6-13) with ADHD. It concluded that high omega-3 levels were associated with improved spelling and attention and reduced oppositional behavior, hyperactivity, cognitive problems and inattention.

What Is The Common Thread In These Studies?

Why, you might ask, am I comparing a study in the elderly, where the concern is retention of cognitive skills, with a study on ADHD in children?

That’s because there is a very important common thread in those two studies. It wasn’t the amount of omega-3 fatty acids in their diet that counted. It was the levels of omega-3 fatty acids in their blood that made the difference.

The first study included a detailed dietary history to estimate the habitual intake of omega-3 fatty acids in the participants.

  • There was no correlation between estimated dietary intake of omega-3 fatty acids and any measure of brain function in those older adults.
  • However, there was a strong correlation between blood levels of omega-3s and brain health in that population group.

The second study was actually a placebo controlled intervention study in which the children were given 1 gm/day of either omega-3 fatty acids or omega-6 fatty acids.

  • Once again, there was no correlation between dietary intake of omega-3 or omega-6 fatty acids and any outcome related to ADHD.
  • However, there was a strong correlation between blood levels of omega-3 fatty acids or omega-3/omega-6 ratio and improvement in multiple measures of ADHD.

How Could The Effect of Dietary Intake And Blood Levels Of Omega-3s Be So Different?

Fish OilBoth studies were relatively small and suffered from some technical limitations, but the most likely explanations are:

  • Inaccurate recall of the participants as to what they eat on a habitual basis. (study 1)
  • Individual differences in the ability of participants to convert short chain omega-3 fatty acids (found in foods such as canola oil, flaxseed oil and walnuts) to the beneficial long chain fatty acids (found in cold water fish). (study 1)
  • Poor compliance in taking the supplements. (study 2)

Why Are These Studies Important?

The most important insight to come out of both of these studies is that it is essential to actually measure blood levels of omega-3 fatty acids and not just rely on dietary intake or supplementation for a valid clinical trial.

That’s a concern because blood measurements of omega-3 fatty acids are expensive and have not been a part of many of the clinical studies that have been performed to date. Even the largest, best designed clinical study is worthless if the dietary recalls aren’t accurate or people don’t take their capsules.

We need to go back and reevaluate many of the clinical studies that have been published.

We need to ask:

  • Are their conclusions valid?
  • Did some studies fail to show that omega-3s were effective simply because they only measured dietary intake and not how much of the omega-3s actually accumulated in the blood?

The Bottom Line

  • High blood levels of omega-3s in the blood correlated with improved brain health in the elderly and reduced ADHD symptoms in children
  • These studies were small, but they are consistent with a number of other studies that have come to similar conclusions.
  • Blood levels of omega-3s are better predictors than dietary intake for evaluating the health benefits of omega-3 fatty acids.
  • Many previous studies that failed to find an effect of omega-3 fatty acids on brain health, heart health or inflammation did not actually measure blood levels of the omega-3 fatty acids. These studies should be reevaluated.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Health Tips From The Professor