Can Resveratrol Improve Memory Performance In The Elderly ?

Written by Dr. Steve Chaney on . Posted in Health Current Events, Healthy Lifestyle, Supplements and Health

red wine benefitsWill Red Wine Make You Smarter?

Author: Dr. Stephen Chaney

It seems like every other day a new headline pops up telling us of yet another nutrient that might improve memory and slow cognitive decline. Perhaps it’s because we having a greying population. Lots of Americans are looking for that magic pill that will allow us to remember where we left the car keys.

This week the banner headlines were about resveratrol, a polyphenol from red wine. The headlines suggested that resveratrol could improve memory performance in healthy older adults. Are those headlines true, and what does that information mean for you?

What is Resveratrol?

Resveratrol is a member of a very large class of compounds called polyphenols that are found in red wine, green tea, and a variety of fresh fruits and vegetables. Polyphenols are very diverse structurally, but most of them are excellent antioxidants. They are one of the reasons that we are constantly being told to eat more fresh fruits and vegetables.

However, resvertrol and a few structurally similar polyphenols are unique in that they also bind to proteins called sirtuins which regulate metabolic processes related to the aging process. In fact, resveratrol garnered a lot of attention a few years ago when Dr. David Sinclair at Harvard Medical School published a study showing that obese mice given resveratrol escaped many of the metabolic consequences of obesity and actually lived longer than mice who were not given resveratrol.

In animal studies resveratrol appears to improve insulin sensitivity and mitochondrial function, lower cholesterol levels and blood pressure, and reduce inflammation and oxidative damage. Human studies have been limited to date, but suggest that resveratrol may impart many of these metabolic benefits to humans as well.

A recent study showed that resveratrol improved memory performance in grey mouse lemurs, a non-human primate species. However, no one had previously looked at whether resveratrol might improve memory in humans.

Can Resveratrol Improve Memory In Healthy Older Adults?

improve memoryIn this study (A. V. Witte et al, The Journal of Neuroscience, 34: 7862-7870, 2014) investigators recruited 46 older (average age 64), overweight (BMI 25-30), adults from Berlin, Germany. All of the subjects were healthy and none of them had any sign of cognitive impairment. For a six month period half of them were given 100 mg of resveratrol twice a day, and half of them were given a placebo (sunflower oil).

At the beginning of the test period they were given a memory test which measures how many of 15 listed words they could recall 30 minutes later. They also underwent a MRI scan that measured brain volume and functional connectivity of the hippocampus, a key region implicated in memory function. Finally, hemoglobin A1c, a measure of long term blood sugar control was measured.

Here are the results:

  • There was a significant effect of resveratrol on retention of words over 30 minutes compared to placebo. Memory improved significantly in the resveratrol group, while it declined slightly in the placebo group.
  • There was no effect of resveratrol on brain volume compared to the placebo (most interventions showing significant effects on brain volume required 2-3 years to demonstrate a significant effect).
  • Subjects in the resveratrol group showed significant increases in functional connectivity of the hippocampus to other brain regions involved learning and memory compared to the placebo group.
  • Subjects in the resveratrol group had lower hemoglobin A1c (better long term blood sugar control) compared to the placebo group.
  • When they statistically evaluated individual patients, the degree of improvement in the word memory test correlated with the increase in functional connectivity of the hippocampus and both of those measures correlated with decreased hemoglobin A1c.

What Does This Study Mean?

This study is promising in that it is well done and is consistent with previous animal studies. However, we need to keep in mind that this is the very first study of this kind. Similar to most first studies, it is small (only 46 subjects) and short in duration (6 months). It also only tested one dose of resveratrol (200 mg/day).

Now that this study has shown that resveratrol might improve memory in healthy older adults, it provides a strong rationale for more clinical studies to test this hypothesis. There is a need for larger, longer term studies in other population groups. Future studies should also evaluate different doses of resveratrol so that we know how much is needed to positively impact mental function.

Can resveratrol improve memory?

The Bottom Line:

  • A recent study suggests that resveratrol, a polyphenol from red wine, improves memory (measured by a word recall test) and functional connectivity of the hippocampus, a region of the brain involved in memory function.
  • This is the very first study of its kind. It was small (46 subjects) and short (6 months). However, it was well designed and consistent with previous animal results. Thus, it should be considered preliminary, but promising. More studies are clearly needed to test this hypothesis.
  • If the results of this study are substantiated, it will not necessary mean that other polyphenols will exert similar effects on memory. The action mechanism of resveratrol is different than most other polyphenols.
  • It also does not necessarily mean that red wine will make you smarter. The 100 glasses of red wine a day that you would need to drink to get the amount of resveratrol used in this study would probably kill more brain cells than the resveratrol could help.
  • Finally, as I said in a recent “Health Tips From the Professor” , there are no “magic bullets” when it comes to preventing cognitive decline. Your chances of reducing cognitive decline are best with a holistic approach that includes healthy diet, exercise, socialization, mental exercises, maintaining a healthy weight, B vitamins and omega-3 fatty acids. If this study is confirmed by future studies, you may be able to add resveratrol supplements to the list.

 

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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Is Our Microbiome Affected By Exercise?

Posted November 6, 2018 by Dr. Steve Chaney

Microbiome Mysteries

Author: Dr. Stephen Chaney

is our microbiome affected by exerciseIn a recent post,  What is Your Microbiome and Why is it Important,  of “Health Tips From The Professor” I outlined how our microbiome, especially the bacteria that reside in our intestine, influences our health. That influence can be either good or bad depending on which species of bacteria populate our gut. I also discussed how the species of bacteria that populate our gut are influenced by what we eat and, in turn, influence how the foods we eat are metabolized.

I shared that there is an association between obesity and the species of bacteria that inhabit our gut. At present, this is a “chicken and egg” conundrum. We don’t know whether obesity influences the species of bacteria that inhabit our gut, or whether certain species of gut bacteria cause us to become obese.

Previous studies have shown that there is also an association between exercise and the species of bacteria that inhabit our gut. In particular, exercise is associated with an increase in bacteria that metabolize fiber in our diets to short chain fatty acids such as butyrate. That is potentially important because butyrate is a primary food source for intestinal mucosal cells (the cells that line the intestine). Butyrate helps those cells maintain the integrity of the gut barrier (which helps prevent things like leaky gut syndrome). It also has an anti-inflammatory effect on the immune cells that reside in the gut.

However, associations don’t prove cause and effect. We don’t know whether the differences in gut bacteria were caused by differences in diet or leanness in populations who exercised regularly and those who did not. This is what the present study (JM Allen et al, Medicine & Science In Sports & Exercise, 50: 747-757, 2018 ) was designed to clarify.  Is our microbiome affected by exercise?

 

How Was The Study Designed?

is our microbiome affected by exercise studyThis study was performed at the University of Illinois. Thirty-two previously sedentary subjects (average age = 28) were recruited for the study. Twenty of them were women and 12 were men. Prior to starting the study, the participants filled out a 7-day dietary record. They were asked to follow the same diet throughout the 12-week study. In addition, a dietitian designed a 3-day food menu based on their 7-day recall for the participants to follow prior to each fecal collection to determine species of gut bacteria.

The study included a two-week baseline when their baseline gut bacteria population was measured, and participants were tested for fitness. This was followed by a 6-week exercise intervention consisting of three supervised 30 to 60-minute moderate to vigorous exercise sessions per week. The exercise was adapted to the participant’s initial fitness level, and both the intensity and duration of exercise increased over the 6-week exercise intervention. Following the exercise intervention, all participants were instructed to maintain their diet and refrain from exercise for another 6 weeks. This was referred to as the “washout period.”

VO2max (a measure of fitness) was determined at baseline and at the end of the exercise intervention. Stool samples for determination of gut bacteria and concentrations of short-chain fatty acids were taken at baseline, at the end of the exercise intervention, and again after the washout period.

In short, this study divided participants into lean and obese categories and held diet constant. The only variable was the exercise component.

 

Is Our Microbiome Affected By Exercise?

is our microbiome affected by exercise fitnessThe results of the study were as follows:

  • Fitness, as assessed by VO2max, increased for all the participants, and the increase in fitness was comparable for both lean and obese subjects.
  • Exercise induced a change in the population of gut bacteria, and the change was comparable in lean and obese subjects.
  • Exercise increased fecal concentrations of butyrate and other short-chain fatty acids in the lean subjects, but not in obese subjects.
  • The exercise-induced changes in gut bacteria and short-chain fatty acid production were largely reversed once exercise training ceased.

The authors concluded: “These findings suggest that exercise training induces compositional and functional changes in the human gut microbiota that are dependent on obesity status, independent of diet, and contingent on the sustainment of exercise.” [Note: To be clear, the exercise-induced changes in both gut bacteria and short-chain fatty acid production were independent of diet and contingent on the sustainment of exercise. However, only the production of short-chain fatty acids was dependent on obesity status.]

 

What Does This Study Mean For You?

is our microbiome affected by exercise gut bacteriaThere are two important take home lessons from this study.

  • With respect to our gut bacteria, I have consistently told you that microbiome research is an emerging science. This is a small study, so you should regard it as the beginning of our understanding of the effect of exercise on our microbiome rather than conclusive by itself. It is consistent with previous studies showing an association between exercise and a potentially beneficial shift in the population of gut bacteria.

The strength of the study is that it shows that exercise-induced changes in beneficial gut bacteria are probably independent of diet. However, it is the first study to look at the interaction between obesity, exercise and gut bacteria, so I would interpret those results with caution until they have been replicated in subsequent studies.

  • With respect to exercise, this may be yet another reason to add regular physical activity to your healthy lifestyle program. We already know that exercise is important for cardiovascular health. We also know that exercise increases lean muscle mass which increases metabolic rate and helps prevent obesity. There is also excellent evidence that exercise improves mood and helps prevent cognitive decline as we age.

Exercise is also associated with decreased risk of colon cancer and irritable bowel disease. This effect of exercise has not received much attention because the mechanism of this effect is unclear. This study shows that exercise increases the fecal concentrations of butyrate and other short-chain fatty acids. Perhaps, this provides the mechanism for the interaction between exercise and intestinal health.

 

The Bottom Line

A recent study has reported that:

  • Exercise induces a change in the population of gut bacteria, and the change was comparable in lean and obese subjects.
  • Exercise causes an increase in the number of gut bacteria that produce butyrate and other short-chain fatty acids that are beneficial for gut health.
  • These effects are independent of diet, but do not appear to be independent of obesity because they were seen in lean subjects but not in obese subjects.
  • The exercise-induced changes in gut bacteria and short-chain fatty acid production are largely reversed once exercise training ceases.

The authors concluded: “These findings suggest that exercise training induces compositional and functional changes in the human gut microbiota that are dependent on obesity status, independent on diet, and contingent on the sustainment of exercise.”

For more details and my interpretation of the data, 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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