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Diet, Supplements, and Cognitive Decline
By Gary F. Zeolla
One of my close relatives died of Alzheimer's Disease and another is currently suffering from dementia. So the question of what steps can be taken to prevent such cognitive decline is very important to me. So I did some research on PubMed as to what dietary steps and supplements can be taken to prevent Alzheimer's Disease (AD) and dementia or at least to slow cognitive decline. This article will summarize the results of my research.
Dietary Patterns Associated with Reduced Risks
Following are some of the more important statements I found in the abstracts on PubMed in regards to diet and the development of AD and dementia:
An adequate intake of antioxidant micronutrients (eg, vitamin C and vitamin E) and anti-inflammatory macronutrients (eg, omega-3 polyunsaturated fatty acids) forms an essential component of extrinsic defenses against brain ageing. There are many epidemiological data to support an association between an inadequate intake of antioxidants and/or fish oils (an important source of omega-3 polyunsaturated fatty acids) and a greater than expected incidence of late onset dementia (Whalley LJ, Starr JM, Deary IJ.).
Essential components of the Mediterranean diet-MUFA [monounsaturated fatty acids], cereals and wine--seem to be protective against cognitive decline (Panza F., et.al.).
Some studies suggest that high intake of vitamins C, E, B6, and B12, and folate [folic acid], unsaturated fatty acids, and fish are related to a low risk of AD, but reports are inconsistent. Modest to moderate alcohol intake, particularly wine, may be related to a low risk of AD (Luchsinger JA, Mayeux R.).
Among 2950 initially non-demented subjects, moderate drinkers had a decreased relative risk of developing a dementia in the subsequent 8 years (RR=0.56) compared to non-drinkers. In a sub-sample of 1416 subjects, those who ate fish or seafood at least once a week had a significant reduced risk of incident dementia adjusted for age and sex (RR=0.66). Lastly, a nested case control study was performed among 182 subjects. Adjusted for confounders, the risk of dementia was significantly increased for the lowest vitamin E concentration compared to the highest one (OR=2.54). (Larrieu S., et.al.).
Dietary niacin may protect against AD and age related cognitive decline (Morris MC., et.al.).
Intakes of saturated fat and trans-unsaturated fat were positively associated with risk of Alzheimer disease, whereas intakes of omega-6 polyunsaturated fat and monounsaturated fat were inversely associated" (Morris)
A change in diet emphasizing decreasing dietary carbohydrates and increasing essential fatty acids (EFA) may effectively prevent AD (Henderson ST.).
After adjusting for age, sex, apolipoprotein E (APOE)-epsilon 4 status, education, and other alcoholic beverages, only intake of up to three daily servings of wine was associated with a lower risk of AD (hazard ratio=0.55, 95% confidence interval=0.34-0.89). Intake of liquor, beer, and total alcohol was not associated with a lower risk of AD (Luchsinger JA., et.al).
Foods to Consume and to Avoid
Looking these excerpts over, the first food that stands out is fish. Fish is the best dietary source there is of omega 3 essential fatty acids. It is also high in polyunsaturated and monounsaturated fatty acids. So the first dietary step a person can take to reduce the risk of cognitive decline would be to include fish in one's diet. And it doesn't take much. One of excerpts above mentions eating "fish or seafood at least once a week," but most sources recommend consuming two or more servings a week.
Related to fish would be nuts and seeds. Like fish, nuts and seeds (especially walnuts and flax seeds) are rich in omega 3, along with omega 6, essential fatty acids. All nuts and seeds are also high in polyunsaturated and monounsaturated fatty acids. They are also excellent sources of vitamin E, one of the antioxidant vitamins mentioned above. And peanuts are especially high in niacin, another mentioned vitamin. And like fish, it doesn't take much. Most studies find benefits from consuming an ounce a day. And an ounce of nuts and seeds is a little less than a quarter of a cup, which is a small handful.
Vitamin C is another antioxidant vitamin mentioned above. Citrus fruits are well known for their rich vitamin C content, but other fruits like kiwi, cantaloupe, and strawberries are also rich sources, as are various vegetables, such as dark green leafy vegetables and broccoli.
Citrus fruits, dark green leafy vegetables, and many other fruits and vegetables are also excellent sources of folic acid. And many vegetables are also good sources of vitamin B6, especially dark green leafy vegetables.
So reducing the risk of cognitive decline would be yet one more reason for consuming more fruit and vegetables. And the consumption of dark green leafy vegetables would be especially recommended in this regard.
One last vitamin mentioned above is vitamin B12. This vitamin is only found in animal foods. So a deficiency of vitamin B12 is a particular concern for vegetarians. In fact, I would say this is one reason why I do not patricianly recommend following a vegetarian diet. And the exceptional benefits of the consumption of fish would be another reason. And fish just happens to be an especially excellent source of vitamin B12.
One last food mentioned above is cereals. In the context of the Mediterranean diet, this would be whole grain cereal.
So fish, nuts and seeds, fruits and vegetables (especially citrus fruits and dark green leafy vegetables), and whole grain cereals stand out as the primary foods to focus on for reducing the risk of AD and dementia.
As for foods to avoid, mentioned above are saturated fats and trans fats. The former are found in certain animal foods like fatty meats, whole milk, and cheeses, while the latter are found in processed and fried foods. Fortunately, food labels generally list the amount of saturated fats the food contains, and the amounts of trans fats are now also appearing on labels. So by reading labels, the consumer can easily know which foods are high in these items and avoid them.
And finally, the next to last excerpt above mentions about "decreasing dietary carbohydrates." The reason for this given in the abstract has to due with fluctuating insulin levels. But what causes such fluctuations is mainly processed carbs, especially refined flour and sugar. The healthy sources of carbs mentioned above would not have such a problem as long as one doesn't go overboard on the fruit and whole grain cereals.
As for alcohol consumption, this can be a difficult area to give recommendations on. There are some potential benefits to alcohol consumption, but there also many potential risks. So I will just make a few general comments.
First, if the reader does not currently drink alcohol, I would not recommend starting to do so just for any possible health benefits. The risks could easily outweigh any potential benefits.
Second, only wine consumption is cited above as having any real benefit. So there is no support of the consumption of beer or hard liquors in this regard.
Third, and most importantly, what is being discussed here is moderate alcohol consumption. One excerpt above refers to "up to three daily servings of wine." However, most authorities recommend consuming only one or two servings a day. Anything more than this can lead to a wide variety of problems.
So I would conclude that if you drink, restrict yourself to only wine and to only one or two drinks a day.
It should be noted that the studies cited above were looking at the consumption of the various nutrients from foods. They were not studying the possible benefits of taking supplements. And I didn't come across very many studies on the possible benefits of supplementing with the various mentioned nutrients. But one study was interesting.
It looked at vitamin E intake. It started out by stating, "High intake of vitamin E from food (tocopherol), but not from supplements (which usually contain alpha-tocopherol), is inversely associated with Alzheimer disease." One possible reason given for this discrepancy is that vitamin E in foods consists of a combination of four different forms of tocopherol (alpha, beta, gamma, and delta) while most vitamin E supplements contain only alpha tocopherol.
The study concludes, "The results suggest that various tocopherol forms rather than alpha- tocopherol alone may be important in the vitamin E protective association with Alzheimer disease" (Morris MC., et.al.).
This is one reason I take Twinlab's Super E-Complex rather than an ordinary vitamin E supplement. The Super E contains all four forms of tocopherol. But still, food should be looked at as the primary source with such a supplement as, well, a supplement.
And the same could be said for the other mentioned nutrients. For instance, I eat a lot of fruit and vegetables, but I still take Twinlab's C 500 Caps. So look to foods first and supplements second. And one caution needs to be mentioned.
One abstract stated:
There is a risk that if folic acid is given to people who have undiagnosed deficiency of vitamin B12 it may lead to neurological damage. Vitamin B12 deficiency produces both an anemia identical to that of folate deficiency but also causes irreversible damage to the central and peripheral nervous systems. Folic acid will correct the anemia of vitamin B12 deficiency and so delay diagnosis but will not prevent progression to neurological damage. For this reason trials of folic acid supplements may involve simultaneous administration of vitamin B12 (Malouf M, Grimley EJ, Areosa SA.).
Such potential problems are why it is important to tell your doctor about all supplements you are taking.
Such potential nutrient imbalances are also why it is good to take a full-spectrum multi-supplement. And for this purpose, I prefer Twinlab's Daily One Caps. The amounts of vitamins C and E it contains are rather low for disease prevention, hence why I take the above two supplements. But the Daily One Caps has more than enough of vitamins B6, B12, and folic acid.
Also available in supplement form is fish oils. But the quality of these varies greatly. At one time I was taking Twinlabs' Omega 3 Fish Oil Softgels. And I think it is a quality product. But I now simply eat fish regularly. And I think this is a better approach.
Another way to supplement omega 3, along with omega 6, essential fatty acids is through the use of flax seed oil. This also can be purchased in softgel form. But an even better approach would be the use of use of flax seed oil in liquid form. I use a teaspoon on my dinner salad. And a good product in this regard is Jarrow Formula's Hi Lignan Flax Seed Oil. I like it as it is organic.
One supplement deserves special mention: Gingko biloba. It is often touted as helping with cognitive decline. And many studies have looked at its possible role in this regard. I found eight abstracts reviewing these studies.
All but one of these abstracts indicated that Gingko biloba is effective to at least some degree in treating various forms of cognitive decline. And these abstracts indicated that Gingko is generally safe, much safer than standard drug therapy. And Ginkgo is less expensive as well. However, these abstracts did refer to Ginkgo as a drug. And it can have adverse reactions to other medications. So it would be best to only take Ginkgo under the direction of a doctor.
It should also be noted that these studies were only looking at Gingko as a treatment for those already suffering from some form of dementia. They did not investigate the question of if taking Gingko would help to prevent dementia. And I could not find any studies that looked at Gingko in that respect.
So I would conclude that if you or a loved one is already suffering from cognitive decline, then it would be a good idea to talk to your doctor about taking Gingko. But there is no evidence at this time for a healthy person to start taking Gingko as a means of prevention of cognitive decline.
If you are interested in taking Gingko, Jarrow Formulas makes a variety of Ginkgo biloba products.
Consuming fish, nuts and seeds, fruits and vegetables, and whole grains while avoiding saturated fats, trans fats, and processed carbs. Not only are these good dietary recommendations in general, but such steps could also potentially aid in the prevention of dementia and Alzheimer's Disease.
Meanwhile, supplementing with a high quality, multi-vitamin, mineral supplement, along with extra vitamin C and E can also have health benefits in general and aid in preventing cognitive decline.
So these are two steps that one can take to not only improve your health in general but also to possibly reduce your risk of cognitive decline. And if one is already experiencing cognitive decline of some sort, Gingko biloba would be a worthwhile treatment to investigate with your doctor.
Abstracts listed in order of citation. PMID stands for the PubMed Identification Number. The reader can easily find any of these abstracts by searching for this number on PubMed.
Foods to Consume and to Avoid:
Whalley LJ, Starr JM, Deary IJ. Diet and dementia. J Br Menopause Soc. 2004 Sep;10(3):113-7. PMID: 15494103.
Panza F, Solfrizzi V, Colacicco AM, D'Introno A, Capurso C, Torres F, Del Parigi A, Capurso S, Capurso A. Mediterranean diet and cognitive decline. Public Health Nutr. 2004 Oct;7(7):959-63. PMID: 15482625.
Luchsinger JA, Mayeux R. Dietary factors and Alzheimer's disease. Lancet Neurol. 2004 Oct;3(10):579-87. PMID: 15380154.
Larrieu S, Letenneur L, Helmer C, Dartigues JF, Barberger-Gateau P. Nutritional factors and risk of incident dementia in the PAQUID longitudinal cohort. J Nutr Health Aging. 2004;8(3):150-4. PMID: 15129300.
Morris MC, Evans DA, Bienias JL, Scherr PA, Tangney CC, Hebert LE, Bennett DA, Wilson RS, Aggarwal N. Dietary niacin and the risk of incident Alzheimer's disease and of cognitive decline. J Neurol Neurosurg Psychiatry. 2004 Aug;75(8):1093-9. PMID: 15258207.
Morris MC, Evans DA, Bienias JL, Tangney CC, Bennett DA, Aggarwal N, Schneider J, Wilson RS. Arch Neurol. 2003 Feb;60(2):194-200. Arch Neurol. 2003 Aug;60(8):1072. Dietary fats and the risk of incident Alzheimer disease. PMID: 12580703.
Henderson ST. High carbohydrate diets and Alzheimer's disease. Med Hypotheses. 2004;62(5):689-700. PMID: 15082091.
Luchsinger JA, Tang MX, Siddiqui M, Shea S, Mayeux R. Alcohol intake and risk of dementia. J Am Geriatr Soc. 2004 Apr;52(4):540-6. PMID: 15066068.
Morris MC, Evans DA, Tangney CC, Bienias JL, Wilson RS, Aggarwal NT, Scherr PA. Relation of the tocopherol forms to incident Alzheimer disease and to cognitive change. Am J Clin Nutr. 2005 Feb;81(2):508-14. PMID: 15699242.
Malouf M, Grimley EJ, Areosa SA. Folic acid with or without vitamin B12 for cognition and dementia. Cochrane Database Syst Rev. 2003;(4):CD004514. PMID: 14584018.
Kanowski S, Hoerr R. Ginkgo biloba extract EGb 761 in dementia: intent-to-treat analyses of a 24-week, multi-center, double-blind, placebo-controlled, randomized trial. Pharmacopsychiatry. 2003 Nov;36(6):297-303. PMID: 14663654.
van Dongen M, van Rossum E, Kessels A, Sielhorst H, Knipschild P. Ginkgo for elderly people with dementia and age-associated memory impairment: a randomized clinical trial. J Clin Epidemiol. 2003 Apr;56(4):367-76. PMID: 12767414.
Gertz HJ, Kiefer M. Review about Ginkgo biloba special extract EGb 761 (Ginkgo). Curr Pharm Des. 2004;10(3):261-4. PMID: 14754386.
Loew D. Value of Ginkgo biloba in treatment of Alzheimer dementia. [Article in German] Wien Med Wochenschr. 2002;152(15-16):418-22. PMID: 12244890.
Sierpina VS, Wollschlaeger B, Blumenthal M. Ginkgo biloba. Am Fam Physician. 2003 Sep 1;68(5):923-6. PMID: 13678141.
Le Bars PL, Kastelan J. Efficacy and safety of a Ginkgo biloba extract. Public Health Nutr. 2000 Dec;3(4A):495-9. PMID: 11276297.
Le Bars PL, Velasco FM, Ferguson JM, Dessain EC, Kieser M, Hoerr R. Influence of the severity of cognitive impairment on the effect of the Gnkgo biloba extract EGb 761 in Alzheimer's disease. Neuropsychobiology. 2002;45(1):19-26. PMID: 11803237.
Schulz V. Ginkgo extract or cholinesterase inhibitors in patients with dementia: what clinical trials and guidelines fail to consider. Phytomedicine. 2003;10 Suppl 4:74-9. PMID: 12807348.
Diet, Supplements, and Cognitive Decline. Copyright © 2005 by Gary F. Zeolla.
Disclaimers: The material presented in this article is intended for educational purposes only. The author is not offering medical or legal advice. Accuracy of information is attempted but not guaranteed. Before undertaking any diet, exercise, or health improvement program, one should consult your doctor. The author is in no way responsible or liable for any bodily harm, physical, mental, or emotional, that results from following any of the advice in this article.
The above article was posted on this site April 1, 2005.
It originally appeared in the free email newsletter FitTips for One and All.
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