Omega-3 Fatty Acids And Brain Health

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues

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.

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Comments (7)

  • mary cardinale

    |

    Steve,

    Excellent information on brain health/fish oil as it provokes many other questions. Now, what could affect the blood levels of Omega-2 fatty acids in the blood. Obviously, many of the flawed studies assumed that if one consumed say 1200 mg of fish oil that it is a slam dunk. So, what factors could affect the absorption of the oil. How does one make sure that the supplements one consumes results in appropriate levels in the blood! Thanks so much for the umbiased and scientific information; it gives pause for thought about many of the other studies that come out over the media.

    Reply

    • Dr. Steve Chaney

      |

      Dear Mary,

      The problems I was talking about related more to inaccurate recall of omega-3 intake in a diet history, failure to faithfully take the omega-3 capsules, or variable ability for our bodies to convert short chain omega-3 fatty acids such as found in canola or flaxseed oil to the beneficial long chain omega-3 fatty acids such as found in fish oil. There is relatively little evidence for differences in the uptake or utilization of the long chain omega-3 fatty acids in fish oil.

      Dr. Chaney

      Reply

  • Steve Harper

    |

    Great detail and yet comprehensible for the non medically affluent in terminology. Intake versus actual blood content of omega 3 that is a good topic. Makes sense of why some studies say one thing and others just the opposite.
    Great material for thought and study.

    Thanks!

    Reply

  • Victoria Waple

    |

    Question: How does one determine what the Optimal Health blood level should be? Thank You!

    Reply

    • Dr. Steve Chaney

      |

      Dear Victoria,

      We don’t yet have sufficient research to say what the optimal blood level of omega-3s is. Most of the research has been done comparing dietary intake of omega-3s with health outcomes. The authors of the study I quoted were measuring blood levels simply to verify the accuracy of their dietary surveys.

      Dr. Chaney

      Reply

  • Victoria Waple

    |

    Another question: Is it safe to take Shaklee OmegaGuard while on a blood thinner?
    Thanks again for your the valuable infomation in your Health Tip newsletters.

    Reply

    • Dr. Steve Chaney

      |

      Dear Victoria,

      You should consult with your doctor and ask them to monitor your bleeding time so that they can help you achieve the proper balance between onega-3s and blood thinning medication.

      Dr. Chaney

      Reply

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Latest Article

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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