Joe: My doctor told me to give up drinking, smoking, and fatty foods.

Sam: What will you do?

Joe: I think I’ll give up my doctor.

I try not to get too excited about memory benefits of supplements, because too often the claims are not substantiated by studies that are well controlled and peer reviewed. I now think resveratrol may be one of the few supplements that benefits brain function.

When I wrote my first blog on research on resveratrol benefits for brain function and memory, there were over 2,000 scientific papers.[1]Don't worry; I am only going to tell you about a few studies.

Resveratrol is an active ingredient in red wine. This compound has been credited for explaining why red-wine drinkers in France, who drink more wine than most people, are healthier than would be predicted by their lifestyle of little exercise and eating lots of cheese. The problem is most studies suggest you would have to drink a 100 or more glasses of red wine a day to get much resveratrol effect (and that effect would obviously be negated by a toxic dose of alcohol). An obviously more healthful choice is the highly concentrated pill forms of resveratrol that are now on the market.

Most of the protective biological actions associated with resveratrol have been associated with its scavenger properties for free radicals and the protective effects that it confers on the heart and diabetes. 

One important study comes from a diabetes research group in Brazil recently who reported a beneficial effect of resveratrol on diabetic rats.[2]Resveratrol (in a modest rat dose of 10 and 20 mg per kilogram per day for 30 days) prevented the impairment of memory induced by diabetes. Resveratrol may be protecting neuron terminals that diabetes can damage. An earlier study by another group showed resveratrol improved glucose metabolism and promoted longevity in diabetic mice.

Another benefit of resveratrol is the anti-oxidant property. The brain produces more free-radical damage than other organs, because it burns so much oxygen. Compared with other organs, the brain has especially low levels of antioxidant defense enzymes. 

One recent study has revealed resveratrol had protective effects against brain damage caused by a chemical that kills acetylcholine neurons. Injection of this toxin into the brain of rats impaired their memory performance in two kinds of maze tasks. The impairment was significantly reduced by repeated injection of resveratrol (10 and 20 mg/kg) per day for 25 days, beginning four days before the toxin injection.[3]

Another recent study examined effects on working memory in mice fed a resveratrol-supplemented diet for four weeks before being injected with a cytokine to induce inflammation and accelerate aging. Resveratrol significantly reduced memory impairment in the aged group, but not in the young adults[4]. The lack of benefit in young adults was a little misleading, in that there was a "ceiling effect" in that the young adults were not impaired by the cytokine injection.

 The practical issue for us is whether resveratrol will help cognitive function in humans, especially healthy humans. It seems likely because other substances that have strong anti-oxidant properties seem to improve memory capability. Because animal studies have shown promise for resveratrol in preventing or treatment several different conditions associated with aging, several human clinical trials have been initiated.[5]

 An impressive new study of older humans, male and female, has just been reported.[6]Twenty-three healthy, but overweight people completed 6 months of daily resveratrol intake (200 mg ― the commercial brand I take has 300 mg/capsule). A paired control group got placebo pills. A double-blind design assured that neither the subjects nor the experimenters knew which individuals were in each group during data processing. Memory tests of word recall revealed significant improvement in the resveratrol group. Resveratrol also increased brain-scan measures of functional connectivity, which identified linked neural activity between the hippocampus and several areas of cerebral cortex.

Because others had shown that resveratrol increased insulin sensitivity in humans, these authors examine several markers important to diabetes. Resveratrol decreased the standing levels of sugar-bound hemoglobin, a standard marker for glucose control.  

What foods besides red grapes have resveratrol? The most likely other sources you would eat or drink are blueberries, cranberries, and peanuts. It is not likely that you could drink or eat enough of such substances to get enough resveratrol to do much good. Because of the scientifically documented benefits of resveratrol, highly concentrated supplements are now on the market (I have been taking it for a couple of years). I haven't given up my two glasses of red wine each day, but I have started taking one of the supplements. I haven't seen any reports that high doses of resveratrol are toxic.

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[1] http://thankyoubrain.blogspot.com/2010/04/resveratrol-red-wine-magic-chemical.htmlApril 4, 2010.

[2] Schmatz R, et al. (2009). Resveratrol prevents memory deficits and the increase in acetylcholinesterase activity in streptozotocin-induced diabetic rats. Eur J Pharmacol. 2009 May 21;610(1-3):42-8. Epub 2009 Mar 19.

[3] Kumar, A. et al. 2007. Neuroprotective effects of resveratrol against intracerebroventricular colchicine-induced cognitive impairment and oxidative stress in rats. Pharmacology.79 (1): 17-26. DOI: 10.1159/000097511

[4] Abraham, J., and Johnson, R. W. 2009. Consuming a diet supplemented with resveratrol reduced infection-related neuroinflammation and deficits in working memory in aged mice. Rejuvenation research. 12 (6): 445-453.  DOI: 10.1089/rej.2009.0888

[5]Smoliga, J. M. et al. (2011). Resveratrol and health – a comprehensive review of human clinical trials.  Mol. Nutrition Food Res. 55: 1129-1141

[6] Witte, A. V., et al. (2014) Effects of resveratrol on memory performance, hippocampal functional connectivity, and glucose metabolism in healthy older adults. J. Neuroscience. 34 23): 7862-7870.

"Memory Medic's latest book is for seniors (Improve Your Memory for a Healthy Brain. Memory Is the Canary in Your Brain's Coal Mine," available in inexpensive e-book format at https://www.smashwords.com/books/view/496252.  See also his recent book, "Mental Biology. The New Science of How the Brain and Mind Relate" (Prometheus).

Remember when you were a child and adults seemed to always be saying, "You are too young. Wait till you get older." Or, they said, "You will understand this better when you grow up." Now that you are older, especially if you are my age, people seem to be saying in the politest way they can, "When are you planning to retire?" "We have to make room for younger workers."

Oh, and if you are in the job market, a young person is often told "I'm afraid you don't have enough experience yet." But if you are over 50 or so, they will say "You are over-qualified for this position."

These inevitable put-downs are bad enough. But what you may not realize is that when you accept such judgments of others, you may well impair your performance capability and development. Here, I report research showing that this effect applies particularly to seniors, and that the effect can be counteracted by the right kind of intervention.

A study by Becca Levy (1) showed that seniors can generate a positive self-stereotype that improves memory performance. Moreover, the effect is more readily established if positive priming is done implicitly, that is without conscious realization. In this study they flashed positive-stereotype words on a screen at a rate fast enough to be registered by the brain but below the level of consciousness. Prior studies had shown that it is rather difficult to improve memory performance with explicit priming, perhaps because such priming is superficial relative to what might occur with implicit conditioning. This point is relevant here because much of our age-stereotype processing, both in youth and older age, is subliminal. While consciously we reject the age-related limitations that others imposed on us, repeatedly experiencing the put-downs grinds away at our resistance by unconscious, implicit means.

Here, a computer subliminally presented 90 seniors with words related either to an old-age image of senility or wisdom. Because all people vary a little in their speed threshold for conscious perception of words on a screen (it takes about 125-250 msecs), the view time was adjusted to be just below threshold for each subject. Before and after the priming intervention, three kinds of memory tests were given: 1) working memory immediately after a test, 2) recall immediately after repeat testing confirmed learning, and 3) recall after a delay in which other tasks were performed.

The group that received subliminal stimulation of positive stereotype words had better memory test scores, a higher estimate of their memory capability, and a more positive outlook on tests that measured attitude about aging. Declines were observed in the group that received negative-stereotype word stimulation.

A second study tested young people in the same way, and no such benefit of positive-stereotype conditioning was evident. This may indicate that a person’s pre-existing self-image governs how one responds to priming. Young people have not been pre-conditioned to think their memory is weak because of age.

A related study showed that a person’s explicit belief in their self-efficacy affects their memory performance (2). Typically, as a person ages, the confidence in memory ability declines. But this study aimed to raise confidence in memory ability in 84 people over 50 by a memory training program that integrated a memory skills training class for six weeks, three hours per week, with elements designed to change beliefs about memory competence. The study showed that by emphasizing mastery, verbal encouragement, reduced anxiety, and modeling skills throughout training, subjects became more convinced that they should believe in themselves and their ability to learn how to be more effective learners. And the memory tests bore out that prediction.

Recent studies by my fellow faculty member at Texas A&M, Lisa Geraci and her collaborator, showed that memory confidence can be easily bolstered in seniors and that, once more confident, they perform better (3). Their review of older literature established that negative stereotype priming can make seniors underperform. In their study, young college students and older adults (70 years average) were divided into equal groups that took a mental task that could be readily completed, or was impossible to complete, or given no task. The task items were clusters of five scrambled words that were to be re-arranged into a comprehensible sentence. Neutral words were used that had no priming relevance to age stereotyping. All subjects then took a free recall of a word list they were allowed to study for two minutes. OIder subjects in the task-success group recalled more words and reported less test-anxiety than those in the task-failure group or in the no-task group. No such task effects were seen in the young adults.

So, how can we apply these findings to everyday life outside the laboratory? Obviously, we have to contrive other ways to provide implicit positive priming. Maybe this could come from making more of an effort to improve memory, as my book Memory Power 101 aims to do. When your memory ability improves from using some established learning principles and techniques, you implicitly know it and that would reinforce positive feelings about memory capability. Indeed, this is what "memory athletes" experience. As they practice memorizing, they get better at it, of course, and this must surely have a subliminal effect on their sense of innate capability which in turn helps them reach memory championship-level performance.

Each of these studies makes the point that if you believe you can remember better, maybe you really can, and that in turn promotes positive feelings about the ability to remember. This becomes a self-perpetuating positive feedback loop for success.  Learning capability improves, in large part because of "learning-set" principles, which is a topic for another day. But as these studies I just summarized show, there is a beneficial component from a change in attitude about one's stereotype. So, for both reasons, I emphasize with my students,

The more you know, the more you can know.

Sources:

1. Levy, Becca. (1996). Improving memory in old age through implicit self-stereotyping. J. Personality and Social Psychology. 71 (6), 1092-1107).

2. West, R. L. et al. (2008). Self-efficacy and memory aging: the impact of a memory intervention based on self-efficacy. Aging, Neuropsychology, and Cognition. Doi: 10.1080/13825580701440510.

3. Geraci, L., and Miller, T. M. (2013) Improving older adults’ memory performance using prior task success. Psychology and Aging. 28 (2), 340-345.