Fruit & vegetables

Food & Supplements

There is little evidence that dietary supplements or changes to the diet improve mental function in young, healthy people.

Changes in diet and dietary supplements may be beneficial to older adults, or those suffering from physical disorders, allergies, depression, stress, etc.

Despite the claims made for many supplements, we can't point unequivocally to any as beneficial. Whether they are of benefit does depend on whether you are lacking in some vitamin and mineral (e.g., Vitamin B12), so it is advisable to have your levels checked.

Food is safer, and the evidence does now seem clear that fruit and vegetables rich in anti-oxidants are of particular benefit.

A perennial topic in the arena of memory improvement is the question of “food for the brain”, and in particular, whether there are dietary supplements that can improve your mental abilities. While my own emphasis is improvement through development and practice of skills, I don’t dismiss the possibility of improvement through more physical means. I myself am a great fan of the “you are what you eat” principle. This is mainly because I suffer from multiple food sensitivities, so the consequences of food are very much a reality for me. That doesn’t mean I believe perfectly healthy people should obsess about their diet. There is another principle that is of great importance: we are all individuals.

For example, a year ago, I wrote of the effects of caffeine on memory, concluding that: “while caffeine may help older adults in the later part of the day, those with hypertension, diabetes, impaired glucose tolerance, or high homocysteine levels, would be wiser to avoid coffee, even if decaffeinated. In general, while caffeine may help you overcome factors that lower your cognitive performance, it does not seem that caffeine has any significant direct effect on memory, although it may well help you pay attention.”

So, caffeine is more helpful for some types of people than others, and is in fact contra-indicated for some. Moreover, the effects are different for those who are accustomed to a high caffeine intake, compared to those who only occasionally consume caffeine. And – here’s the real kicker – I also know from personal experience that the effects of caffeine are highly individual: I myself respond to caffeine not with the usual increased alertness, but in fact with decreased alertness. It makes me sleepy!

I do think there are physical factors of far greater importance than diet. Sleep is the obvious one. Individual differences don’t show up in the basic need to have enough sleep, and the right sort of sleep, to optimize brain functioning, but they do of course show up as regards how much sleep is right for us. That also, is something that changes with age, and, I imagine, health, throughout our lifespan.

Another physical factor which should be given due weight is exercise. While its effect is not as great as sleep (I don’t think anything rivals the importance of sleep!), I would give it more importance than diet because its effect is far more consistent. I don’t think anyone would fail to benefit mentally from increased physical fitness (which is not to say there isn’t a level of fitness beyond which no more mental improvement will occur).

Diet, on the other hand, depends a great deal on the individual. There is little evidence that dietary supplements or changes to the diet improve mental function in those who don’t suffer from any of the conditions which can adversely affect brain function — e.g., aging, physical disorders, depression, stress, etc.

In other words, if you are a relatively young person with no health problems, I suggest you concentrate on getting enough sleep and exercise, and learning and practicing effective memory strategies.

If you have any conditions which can adversely affect brain function I would also emphasize doing this! But, additionally, I do think there are foods and supplements you can take which may well significantly improve your brain function.

Which ones? Here we enter the area of individual difference. To find out what is effective for you, you should start with the research. What foods and supplements have been demonstrated to be effective in improving cognition?

Here we enter an area fraught with difficulty. News reports come out about foods and supplements all the time, and today’s world is filled with people hawking “health” products. How do we know what to believe?

The first thing, of course, is to ascertain whether the claims are backed up by research. But that’s not as easy as it sounds, because every seller of such products knows the importance of sounding as if research has proven the effectiveness of their product. (Actually, I automatically disavow any text which talks of research “proving” something. No researcher worth his salt would ever make such a claim.)

How do we determine the genuineness and reliability of the research? First, and most importantly, by assessing the source. For example, I only cite research from reputable academic journals, or academic conferences. I also give greater weight to research from researchers whose work I know of. Hopefully, by so doing, I also make myself a reliable source.

This is not, however, infallible, for even well-respected journals can make mistakes. For example, very topically, the truthfulness of a widely reported study of a nutritional supplement's effects on thinking and memory in the elderly has recently been cast into doubt (actually, this is a rather polite phrase for the comments now being made: “scientists who reviewed the paper had found the methods and statistical findings so unlikely that they wondered whether the study had actually been done”; "The statistics were not just implausible, they were impossible.")

Nevertheless, the very shock with which these questions are being raised demonstrates that, by and large, the system does work. We cannot expect certainty.

Having approved the source, the second thing to consider is the extent to which the research has been replicated. One study does not make an answer! It is indicative only. It is interesting.

Even a second study is little more than another support. Before we can say, “You know, I really think there’s something to this”, we need a number of studies building together from different angles.

So, a study showing that sage can help cognitive function in healthy young adults (there is indeed such a study) is interesting. Given that sage is easy to grow, and commonly consumed (one doesn’t need to worry about toxicity), I would go so far as to say, give it a try! But I wouldn’t give a lot of weight to the research until more studies had been carried out. (I would, however, happily drink sage tea everyday on the off chance, except it turns out – I really can’t believe this! – I’m sensitive to sage, too.)

On the other hand, for a product that is expensive, or has potential side-effects, I would wait for more evidence to come in before trying it. Okay, we’ve looked at the research, we’ve found the foods and supplements of potential benefit. What next?

Next, you look at your own particular problems.

For example, my main problem is food sensitivities. The first, most dramatic, thing I did to overcome my increasing mental sluggishness was: stop eating foods which turned out to be bad for me! After concentrating on that for a year or two, with my physical and mental problems much improved (but not gone), I turned my attention to the damage done to my body over the long period during which I was unaware of my food sensitivities. I now take B12, which I am sure has had a significant effect on my brain, and have recently started taking iron (as a woman of childbearing age). I also take other mineral supplements, principally to overcome deficiencies in my environment (New Zealand’s soil is deficient in a number of minerals), and lecithin (partly because of the deficiencies in my diet as a result of having to avoid certain foods).

The final step, once you’ve established the possible foods and supplements which are worth trying, is to see whether they are effective for you. Remember me and the coffee. What works for one doesn’t necessarily work for another (and may indeed be harmful). But don’t try everything at once! One at a time, and the most likely first.

So, what foods and supplements might be of benefit to your brain?

Most of the research into the cognitive benefits of diet and supplements has been concerned with seniors, with alleviating the effects of age on the brain. This is consistent with the belief that there is little, if any, benefit to be gained by young, healthy adults. Having said that, however, the following have been shown to be of benefit in at least one study:

  • creatine
  • sage
  • lemon balm
  • a diet high in soy products

Remember my comment about the reliability of single studies! However, since three of these four are all perfectly “natural” food items, there would be little danger in trying these out.

Several substances are worth mentioning as having been of particular interest to researchers for their potential benefits to brains suffering from the effects of age:

  • gingko biloba
  • ginseng
  • choline (lecithin)
  • vitamin B12
  • phosphatidylserine (PS)
  • acetyl-L-carnitine (ALC)
  • antioxidants (particularly vitamin E)

This article originally appeared in the May 2004 newsletter.

Benefits of fruit & vegetables for cognition

A number of studies have pointed to the benefits of a diet rich in fruit and vegetables for memory and cognition in older adults. These benefits are thought to accrue from the antioxidants present in these foods, of which some are more important than others.

The anthocyanins appear to be the best — these are responsible for the reds, purples, and blues in some plants. Several studies have affirmed the cognitive benefits of blueberries and Concord grape juice (Concord grapes are particularly purple). Cell studies have also found the compounds in blackcurrants protect neurons from stress, such as that caused by the Alzheimer's peptide amyloid-beta. The darker the fruit, the more anthocyanins, and presumably the more powerful it will be. Another compound in blueberries called pterostilbene apparently, like resveratrol, which is found in grapes and red wine, lowers cholesterol. Yet another compound, called quercetin, has been found to protect against cell damage. This compound is also found in blueberries, and also cranberries. A particularly good source is apples, and red ones are best.

All of this perhaps explains why it is so much better to eat well rather than hope to receive what you need from dietary supplements! And do note that in most cases, most of the 'good' compounds are in the skin. That's why juices (and wines!) are often better ways of consuming these foods.

Of the vegetables, green leafy vegetables, especially spinach, have been found to be especially beneficial. Onions are also a good source of quercetin. Spirulina (not really a vegetable, I know) also appears to be of benefit.

As a rule of thumb, the best fruits and vegetables are those with the most color. And, obviously, it's the color you want to eat (so no peeling your nice red apple!).

See the news reports

Strawberries lower cholesterol

A study in which 23 healthy volunteers ate half a kilo of strawberries every day for a month has found that their levels of bad cholesterol and triglycerides reduced significantly.

http://www.eurekalert.org/pub_releases/2014-02/f-sf-slc022514.php

Old, sprouting garlic even better than fresh

"Sprouted" garlic — old garlic bulbs with bright green shoots emerging from the cloves — have been found to have even more heart-healthy antioxidant activity than fresh garlic.

http://www.eurekalert.org/pub_releases/2014-02/acs-dto022614.php

Supplements don’t reduce risk of cardiovascular disease in elderly

Data from AREDS2, involving 4,203 older adults with age-related macular degeneration, has found that daily dietary supplements of either omega-3 polyunsaturated fatty acids (also found in fish) or lutein and zeaxanthin (nutrients found in green leafy vegetables) were not associated with reduced risk for cardiovascular disease (CVD).

http://www.eurekalert.org/pub_releases/2014-03/tjnj-sna031414.php

Mediterranean diet may lower risk of diabetes

A review of 19 studies involving over 162,000 people has found that adherence to the Mediterranean diet was associated with a 21% reduced risk of diabetes, with a greater effect (27%) for those at high risk for cardiovascular disease. The association was found in both European and non-European groups.

The research was presented at the American College of Cardiology's 63rd Annual Scientific Session.

http://www.eurekalert.org/pub_releases/2014-03/acoc-mdm032614.php

More support for heart-healthy benefits of Mediterranean diet

A very large Italian study provides more evidence that the Mediterranean diet reduces inflammation, with their finding that those with a greater adherence to such a diet had significantly lower levels of platelets and white blood cells. These are both inflammatory markers: high platelet counts are associated with both vascular disease and non-vascular conditions such as cancer, and a high white blood cell count is a predictor of ischemic vascular disease.

Tart cherry juice improves sleep for insomniacs

A small trial involving seven older adults with insomnia has found that when they consumed 8 ounces of tart cherry juice twice daily for two weeks, they were able to sleep more than an hour longer each night (averaging 84 minutes) compared to when they took the placebo, and their sleep tended to be more efficient.

Grape skin extract may help treat diabetes

Preliminary studies have demonstrated that grape skin extract exerts a novel inhibitory activity on hyperglycemia and could be developed to aid in diabetes management.

http://www.eurekalert.org/pub_releases/2014-05/wsu--gse050814.php

Oxidants not all bad?

A finding that free radicals promote longevity in the roundworm challenges the theory that free radicals (oxidants) are damaging and cause aging.

http://www.eurekalert.org/pub_releases/2014-05/mu-wdk050714.php