This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each day, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.
Vitamins, Minerals and the Brain
Folate sufficiency has long been associated with protection of mental ability and particularly so in older adults. The link between folate and brain health was confirmed by the results of a “gold standard” randomized, placebo-controlled human clinical trial, reported very recently in the prestigious medical journal Lancet.2 During the 3 years of this study, men and women who were over 50 years old consumed either a placebo tablet or 800 mcg of folic acid daily (folic acid is a commonly used form of folate in dietary supplements). After 3 years, the subjects who had been supplementing their diets with folic acid had experienced greater memory and recall skills, quickness of thought and ability to react physically to a visual stimulus.
In these same subjects, as reported separately in the Annals of Internal Medicine this amount of supplemental folic acid was shown to support hearing function and prevent normal decline of hearing with age.3 In addition, after 3 years of folic acid supplementation, all of the supplemented subjects who had higher levels of homocysteine at the beginning of the study, but none of the initially hyperhomocysteinemic “placebo” subjects, had normalized their blood homocysteine concentrations. What is surprising is that in spite of massive governmental efforts to convince adults to consume 400 mcg of folic acid daily, none of the subjects in this study were consuming more than 250 mcg daily before the study began.
These experimental findings echo an avalanche of observational studies published recently in the American Journal of Clinical Nutrition. For example, the greater the dietary intake of folate by men and women over the age of 69, the better their language skills (word recognition and use), memory recall, ability to copy simple drawings (a test of visual-motor integration) and ability to think abstractly.4
Similarly, the abilities of Chinese men and women over 55 years old to learn and use new words and to remember facts were greater the more folate and folic acid they consumed on a daily.5 In another study the diet and cognitive abilities of men over 50 years old and participating in the Veterans’ Affairs Normative Aging Study were measured. Compared to the men who were consuming the current RDA for folate, those men consuming at least 25% more folate exhibited better visual-motor integration and were better able to remember the meanings of words. 6
Yet another study reported that the overall cognitive functioning ability of 85-year old men and women improved as daily folate intake increased.7 Still more research reported that in men and women over the age of 65, as dietary folate intake increased, so also did verbal learning ability, problem-solving ability and the speed of mental information processing.8 Finally, the onset of clinically important age-related loss of overall cognitive function was delayed in men and women with the greatest dietary intakes of folate9, indicating the memory-supportive ability of this critical vitamin.
All of these benefits occurred whether folate was consumed as foods or as supplements in the form of folic acid.
Clearly, folate and folic acid are staunch supporters of brain health – especially healthy brain aging.
The importance of the B-vitamins during human fetal development cannot be overemphasized. Certainly, the prevention of neural tube defects with folate is “proof of principle” – contrary to some old misconceptions among obstetricians, maternal nutrition has a profound impact on even the earliest stages of the formation and development of the human mind. As shown most recently in work published in Brain Research poor thiamin status during pregnancy (which affects between 1 in 5 and 1 in 10 of all human embryos) stunts the size of the newborn brain by effectively shortening the lives of the first generations of brain cells.10
Choline is a B-vitamin-like nutrient that is required for the synthesis of essential components of nerve and brain cell membranes. In humans, the rate of synthesis of these components is governed by the availability of choline in the brain, which itself is determined by dietary choline intake. When incoming supplies of choline are inadequate, existing neuronal cell membranes will be “cannibalized” for their choline – obviously a losing proposition in the long run. In contrast, dietary supplementation with choline prevents such avoidable loss of brain cell integrity.
Because vitamin E is a strong antioxidant, especially in tissues with large ratios of cell membranes to total cell volume (such as the brain), it has long been thought that this vitamin must play an important, health-sustaining role in protecting brain membrane lipids from oxidation. Such a role has been confirmed by the research results that have been published very recently in the Chinese medical journal, Acta Biochimica et Biophysica Sinica.11 When human brain cells were grown in the laboratory and were exposed to ß-amyloid plaques, the cells suffered widespread oxidative damage. However, when vitamin E also was present, the cells were protected from such damage. These findings confirm that vitamin E is a strong antioxidant protector within the human brain and promotes healthy brain structure.
The usefulness of any nutrient to the brain depends on the ability of that nutrient to reach and enter the brain. Several systems, together called the “blood-brain barrier,” work to regulate the nature and amount of both desirable and undesirable compounds and nutrients that can gain access to the human brain. For example, selenium is a very beneficial antioxidant for the central nervous system, once it passes through the blood-brain barrier. However, as shown in research on live mice published recently in the Journal of Biological Chemistry the ability of selenium to reach the brain is hindered unless the amount of selenium in the blood is sufficient to activate the carrier proteins that transfer selenium from the blood into the brain.12 In other words, if dietary selenium is inadequate, the brain can become effectively “selenium starved.” Of course, selenium has immense usefulness as an antioxidant in other tissues. Hence, the body requires selenium for other needs, ultimately potentially depriving the brain when levels are inadequate.
Next Best Kept Secrets to Healthy Aging topic:
Vitamins, Minerals and the Cardiovascular System
2. Durga J, van Boxtel MP, Schouten EG, Kok FJ, Jolles J, Katan MB, Verhoef P. Effect of 3-year folic acid supplementation on cognitive function in older adults in the FACIT trial: A randomised, double blind, controlled trial. Lancet 2007;369:208-216.
3. Durga J, Verhoef P, Anteunis LJ, Schouten E, Kok FJ. Effects of folic acid supplementation on hearing in older adults: A randomized, controlled trial. Ann Intern Med 2007;146:1-9.
4. McCracken C, Hudson P, Ellis R, McCaddon A; Medical Research Council Cognitive Function and Ageing Study. Methylmalonic acid and cognitive function in the Medical Research Council Cognitive Function and Ageing Study. Am J Clin Nutr 2006;84:1406-1411.
5. Feng L, Ng TP, Chuah L, Niti M, Kua EH. Homocysteine, folate, and vitamin B-12 and cognitive performance in older Chinese adults: Findings from the Singapore Longitudinal Ageing Study. Am J Clin Nutr 2006;84:1506-1512.
6. Tucker KL, Qiao N, Scott T, Rosenberg I, Spiro A. High homocysteine and low B vitamins predict cognitive decline in aging men: The Veterans Affairs Normative Aging Study. Am J Clin Nutr 2005;82:627- 635.
7. Mooijaart SP, Gussekloo J, Frolich M, Jolles J, Stott DJ, Westendorp RG, de Craen AJ. Homocysteine, vitamin B-12, and folic acid and the risk of cognitive decline in old age: The Leiden 85-Plus study. Am J Clin Nutr 2005;82:866-871.
8. Duthie SJ, Whalley LJ, Collins AR, Leaper S, Berger K, Deary IJ. Homocysteine, B vitamin status, and cognitive function in the elderly. Am J Clin Nutr 2002;75:908-913.
9. Ravaglia G, Forti P, Maioli F, Martelli M, Servadei L, Brunetti N, Porcellini E, Licastro F. Homocysteine and folate as risk factors for dementia and Alzheimer disease. Am J Clin Nutr 2005;82:636-643.
10. Oliveira FA, Galan DT, Ribeiro AM, Santos Cruz J. Thiamine deficiency during pregnancy leads to cerebellar neuronal death in rat offspring: Role of voltage-dependent K(+) channels. Brain Res 2007;1134:79-86.
11. Dai X, Sun Y, Jiang Z. Protective effects of vitamin E against oxidative damage induced by Aß(1-40)Cu(II) complexes. Acta Biochim Biophys Sin 2007;39:123-130.
12. Hill KE, Zhou J, Austin LM, Motley AK, Ham AJ, Olson GE, Atkins JF, Gesteland RF, Burk RF. The selenium-rich C-terminal domain of mouse selenoprotein P is necessary for supply of selenium to brain and testis but not for maintenance of whole-body selenium. J Biol Chem 2007 Feb 20 (www.jbc.org/cgi/doi/10.1074/jbc.M700436200).