American Omega-3 Deficiency

Written by Dr. Steve Chaney on . Posted in Food and Health, Health Current Events, Omega-3 Deficiency, Supplements and Health

Is There an American Omega-3 Deficiency?

Author: Dr. Stephen Chaney

omega 3 deficiencyOmega-3s have been controversial in recent years.  However, virtually everyone agrees that omega-3 intake in North American is low. But, would you believe that the United States and Canada are dead last with respect to omega-3 status – that we are among the countries with the lowest omega-3 status in the world? Is there an American omega-3 deficiency?  That is what a recent study suggests!

Omega-3 Deficiency in Americans

Previous studies have suggested that the American and Canadian diets were deficient in long chain omega-3s like EPA and DHA, but those studies were based on 24-hour diet recalls or food frequency surveys which might underrepresent the true amount of omega-3s in the diet. Therefore, a group of investigators from the United States and Canada decided to look at blood levels of EPA and DHA.

This study (Stark et al, Progress In Lipid Research, 63: 132-152, 2016) was a meta-analysis of 298 studies that recorded blood levels of EPA and DHA. These studies were from 36 counties and distinct regions around the world. They converted all of the measurements to a common unit expressed as percent by weight of EPA + DHA relative to the total weight of fatty acids in the blood.

American omega-3 deficiencyThey combined all studies from a given country or region to give an average value of percent EPA + DHA and then divided the countries and regions into four groupings based on the average weight percentage of EPA + DHA in the blood. If all that seems confusing, the figure on the right (taken from Stark et al, Progress In Lipid Research, 63: 132-152, 2016) should clear things up.

  • Red = very low (< 4%) EPA + DHA levels
  • Orange = low (4-6%) EPA + DHA levels
  • Yellow = moderate (6-8%) EPA + DHA levels
  • Green = adequate (>8%) EPA + DHA levels
  • Grey = no valid measurements in those countries

It is clear from this study that most Americans and most Canadians don’t do a very good job of incorporating omega-3 fatty acids into their diet, as several previous dietary surveys have suggested.  This could contribute to omega-3 deficiency.

Is The United States Dead Last In Omega-3 Status?

The global map of EPA + DHA blood levels certainly suggests that the United States is among a handful of countries with the very lowest omega-3 status. There are a few caveats, however.

  • As the large areas of grey indicate, there are a number of countries with no valid omega-3 blood measurements. The United States might have lots of company in the very low omega-3 status category.
  • There are some very large countries like Russia which have relatively few omega-3 blood measurements, and those measurements are only from a few regions of the country. The average omega-3 status for the entire country might be lower than indicated in this map.

On the other hand, there are lots of omega-3 blood measurements from countries like Japan, so it is clear that there are countries with much better omega-3 status than the United States.

What Does This Study Mean To You?

The important questions are, of course:Does it matter? What do these blood levels of EPA + DHA actually mean? Is < 4% EPA + DHA low enough to matter? What are the health consequences of low omega-3 status?  If you have an omega-3 deficiency, what are the risks?

Let’s start with the first question: How do we translate a blood level of EPA + DHA into how much we should be getting in our diet? While there is no established Dietary Reference Intake for EPA + DHA, several expert panels and international organizations have made recommendations for EPA + DHA intake. Those recommendations generally range from 250 mg/day to 500 mg/day for general health and 500 mg/day to 1,000 mg/day for heart health. Unfortunately, most people in the United States and Canada consume less than 200 mg/day of omega-3 fatty acids, and most of those are short chain omega-3s that are inefficiently converted to the long chain EPA and DHA.

More importantly, a recent study (Patterson et al, Nutrition Research, 35: 1040-1051, 2015) has examined how much additional EPA + DHA must be consumed by someone eating a typical North American diet to significantly improve their omega-3 status. It showed that:

  • 200 mg/day of EPA + DHA is required to improve omega-3 status from very low to low.
  • 500 mg/day of EPA + DHA is required to improve omega-3 status from very low to moderate.
  • 1250 mg/day of EPA + DHA is required to improve omega-3 status from very low to adequate.

omega-3 for heart healthIt is no surprise that these numbers correlate so well. My recommendation would be to consume at least 500 mg/day of EPA + DHA for general health and at least 1,000 mg/day for heart health.

Now let’s look at the last question: What are the health consequences of low omega-3 status? There are multiple health benefits associated with optimal omega-3 status, but the best evidence is for the beneficial effects of omega-3s on fetal and infant neurodevelopment and heart health. For example:

  • In case you have been confused by recent studies suggesting that omega-3s have no effect on heart health you should know that most of those studies were looking at the effect of EPA + DHA in patients who were already taking 3 or 4 heart medications. The studies actually concluded omega-3s provided no additional benefits in people already taking multiple heart medications. That is a totally different question.

Where Should You Get Your Omega-3s?

fish oil supplementsNow that you know how important the long chain omega-3s, EPA and DHA, are for your health, and you know that most of us have a very poor omega-3 status and therefore have an omega-3 deficiency , your next questions are likely to be: “What’s the best way to improve my omega-3 status?” and “Where can I find EPA and DHA in my diet?” The answer is complicated.

  • Cold water, oily fish like salmon are a great source of EPA and DHA. Unfortunately, our oceans are increasingly polluted and some of those pollutants are concentrated even more in farm raised fish. A few years ago a group of experts published a report in which they analyzed PCB levels in both wild caught and farm-raised fish from locations all around the world (Hites et al, Science 303: 226-229, 2004) . Based on PCB levels alone they recommended that some wild caught salmon be consumed no more than once a month and some farm raised salmon be consumed no more than once every other month!

Unfortunately, when you buy salmon in the grocery store or your favorite restaurant, you can ask whether the salmon is wild or farm-raised, but you have no idea where the salmon came from. You have no idea how safe it is to eat. I love salmon and still eat it on occasion, but not nearly as frequently as I used to.

As an aside, the buzzword nowadays is sustainability. I support sustainability. However, the easiest way to assure that fish are sustainable is to raise them in fish farms. When a waiter tells me how sustainable the “catch of the day” is, I ask them how polluted it is. If they can’t answer, I don’t buy it. My health is more important to me than sustainability.

  • Nuts, seeds, and canola oil are good sources of ALA, a short chain omega-3 fatty acid. These food sources are less likely to be contaminated, but the efficiency of conversion of ALA to EPA and DHA is only around 5-10%. In other words, you need to eat a lot of ALA-rich foods to enjoy the health benefits associated with EPA and DHA.
  • That leaves fish oil supplements, but you need to remember that the EPA + DHA supplements you purchase in the health food store come from polluted fish. Unfortunately, many manufacturers have inadequate purification and quality control standards. In other words, neither you nor they know whether their omega-3 products are pure. You need to make sure that the omega-3 supplement you purchase is made by a manufacturer with stringent quality control standards.

 

The Bottom Line

 

  • A recent study has shown that most Americans are deficient in long chain omega-3s like EPA and DHA. In fact, the mainland United States and Canada were tied with half a dozen other countries for the lowest omega-3 status in the world.  Omega-3 deficiency in Americans seems to be the worst.
  • That is unfortunate because recent studies have shown that optimal blood levels of EPA and DHA are associated with a number of health benefits, especially fetal and infant neurodevelopment and heart health.
  • Other studies suggest that most Americans should consume an extra 500 mg/day of EPA + DHA for general health and at least 1,000 mg/day for heart health.
  • Unfortunately, it is not easy get those levels of EPA and DHA from our diet:
  • Oily, cold water fish are a great source of EPA and DHA, but our oceans are increasingly polluted and experts recommend that some fish that are the best sources of EPA and DHA be consumed no more than once a month. The situation is even worse for farm-raised fish.
  • Of course, nowadays the buzzword for fish is sustainability, but sustainability does not guarantee purity. Sustainable fish can be just as polluted as the worst of the farm raised fish.
  • seeds and canola oil are great sources for ALA, a short chain omega-3 fatty acid. This source of omega-3s is less likely to be contaminated, but the efficiency of conversion of ALA to EPA and DHA in our bodies is only around 5-10%.
  • Fish oil supplements can be a convenient source of the EPA and DHA you need, but the fish oil often comes from polluted fish and many manufacturers have inadequate purification methods and quality control standards. If you choose fish oil supplements as your source of omega-3s, be sure to choose a manufacturer with stringent quality control standards. Otherwise, neither you nor the manufacturer will know whether their omega-3 supplement is pure.

 

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.

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A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

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.

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