Vitamin E Keeps Your Brain Razor-Sharp
By Aaron W. Jensen, Ph.D.
You're committed to better health, right? You've decided that you're going to do your best to eat right, stay in shape, and improve your healthy outlook on life. After all, you've got a lot to live for. You want to live long, live well, and by all means keep your brain sharp - because physical health means nothing without a lively brain. (No matter how powerful a computer's hardware components may be, it's just a big paperweight if the CPU is "fried.")
So you set yourself to the task. At the dinner table, you heap vegetables onto your plate, eat fish, turkey, and chicken rather than red meat, and try to forgo dessert. At lunchtime you eat salads instead of fast food. And at breakfast, you ditch the muffins and doughnuts in favor of fortified, low-glycemic cereals and a colorful selection of fresh fruit. Good for you! You're doing all the right things. Well, maybe not all. A nagging question remains: are you getting all the vitamins, minerals, and other nutrients you need to live life to the fullest and remain mentally acute?
Most Americans Need More Vitamin E
Nutritional surveys show that most Americans are deficient in some extremely important vitamins and minerals. For example, most of us don't get as much vitamin E from dietary sources as we should, because we don't eat enough vitamin E-rich foods (such as nuts and seeds). Just because you have a good diet doesn't necessarily mean that you're getting all the important nutrients you need in the amounts you need. This is especially true of older people, whose bodies no longer extract certain nutrients from food as efficiently as they once did.
A significant number of adults in
the USA - 28% of women and
29% of men - have low serum
levels of vitamin E
A national health survey (NHANES III, the National Health and Nutrition Examination Survey) was conducted between 1988 and 1994 to determine the typical nutrient intake of Americans. Investigators at the Centers for Disease Control and Prevention (CDC) analyzed the data, which were collected from 16,300 adults 18 years of age or older, and they concluded that a significant number of adults in the USA - 28% of women and 29% of men - have low serum levels of vitamin E (even by the low standards of recommended intake applied in the survey).1 Further analysis revealed that 41% of blacks, 28% of Mexican-Americans, and 26% of whites have low vitamin E levels. Clearly, getting sufficient vitamin E is a problem for many of us (see the sidebar).
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Dietary Sources of Vitamin E Supplementation with vitamin E is advisable for everyone, mainly for the well-established cardiovascular benefits it offers. That doesn't mean, however, that you should overlook good dietary sources of this wonderful vitamin. Although it's almost impossible to have a clinical vitamin E deficiency, many diets are low in this substance, mainly because they contain a lot of processed foods (processing destroys vitamin E). And the diets of some health zealots are very low - sometimes too low - in fat, which can be problematic because most vitamin E comes from fatty foods, such as vegetable oils, nuts, and seeds. Best Dietary Sources of Vitamin E
Source: USDA Nutrient Database. The abbreviation "mg ATE" stands for "milligrams of alpha-tocopherol equivalents," a way of expressing the biological activity of vitamin E. A more common unit of measure for vitamin E is the international unit (IU). |
Our Brains Need Abundant Vitamin E
Vitamin E has received a huge amount of press lately, because it's an important antioxidant - one of those beneficial nutrients that protect our tissues from the destructive effects of free radicals.* An important aspect of vitamin E's role as an antioxidant is the fact that it's fat-soluble (unlike vitamin C, e.g., which is water-soluble). Consequently, vitamin E is exceedingly valuable in protecting cell membranes (which are fatty in composition) from oxidative damage caused by free radicals. By helping to keep the membranes healthy, vitamin E helps keep the entire cell healthy as well. But its benefits go well beyond that.
*Actually, vitamin E is not a single compound, but a group of eight closely related compounds: four tocopherols and four tocotrienols. All eight have biological activity, but the most active one is alpha-tocopherol. Another one, gamma-tocopherol, may contribute significantly to human health in ways that have not yet been recognized (see "Vitamin E Protects Against Prostate Cancer, and More" in Life Enhancement,September 2002).
All the body's tissues contain lipids (fats and other fatty compounds), but the brain is especially rich in these vital substances, which are highly susceptible to oxidative damage from free radicals. The brain therefore requires a great deal of antioxidant protection - all the more so because it consumes a disproportionate amount of the body's oxygen supply, making it that much more vulnerable to oxidative damage. Not surprisingly, recent research suggests that increased intake of vitamin E helps preserve brain function and protect against neuronal (nerve-cell) degeneration. In essence, a healthy intake of vitamin E can prevent or slow the rate of cognitive decline as the brain ages.
A healthy intake of vitamin E can
prevent or slow the rate of
cognitive decline as the brain
ages.
Vitamin E Retards Cognitive Decline
Researchers in Chicago performed a study on 2889 older individuals (aged 65-102, with an average age of 74) to determine whether antioxidants in their diet protect against age-related cognitive decline.2 They determined the typical dietary intake of the participants, calculated their specific intake of antioxidants, and performed a variety of neuropsychological tests to evaluate the participants' cognitive abilities at the beginning and end of the study (the average follow-up period was 3.2 years).
The researchers investigated the potential neuroprotective effects of several antioxidants, including vitamin E, vitamin C, and beta-carotene (a precursor of vitamin A). Only one of these nutrients, however - vitamin E - was found to protect significantly against cognitive decline. There was only a weak link between the rate of cognitive decline and vitamin C intake, and no link at all with beta-carotene intake. (Although beta-carotene and other vitamin A precursors have antioxidant activity in laboratory experiments, they do not generally show this activity in actual human bodies.)
High antioxidant intake may delay
the onset of dementia. Vitamin E's
ability to protect neurons may thus
have an important bearing on
healthy neurological aging.
Your Mind Could Be 8-9 Years Younger
The Chicago researchers analyzed their data in two different ways - first by looking at the amount of vitamin E from food sources only, and second by considering the total vitamin E intake from both food and supplements. With both approaches, the conclusion was the same: those individuals with the highest intake of vitamin E exhibited the least cognitive decline. Specifically, when subjects in the highest quintile (the highest one-fifth, 20%) of vitamin E intake were compared to those in the lowest quintile, the former group was found to have had a 36% reduction in the rate of cognitive decline compared with the latter group.
The researchers reached this startling conclusion:
Vitamin E intake from foods and supplements was associated with reduced cognitive decline in this older biracial
population. . . . The effects on cognitive decline in the highest quintiles of vitamin E intake (total or from foods only) were equivalent to a corresponding decrease in age of 8 to 9 years.
In other words, just by maintaining a high intake of vitamin E from food alone, it was possible to avoid the equivalent of an 8-to-9-year cognitive aging effect caused by a low intake of this vitamin. The supplement users' 33-fold higher intake of vitamin E (in the highest quintile of that group) conferred no additional advantage. Does that mean that supplementation with vitamin E has no value? Certainly not! If you are not in the highest quintile of vitamin E intake from food alone (and 80% of the population is, by definition, not in that quintile), supplementation would have definite value. Besides, there is much more to vitamin E than its effect on cognitive function, as we will see below.
Vitamin E May Combat Dementia
Given the important role that vitamin E evidently plays in protecting cognitive function, there is hope that supplementation with this vitamin may help in preventing, or at least delaying the onset of, serious neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. Alzheimer's research is particularly promising in this area, and several studies suggest that high antioxidant intake may delay the onset of dementia. The ability of vitamin E to protect neurons against oxidative damage may thus have an important bearing on healthy neurological aging.
The value of vitamin E does not stop at the brain, of course. It has long been known that other parts of the body - especially the heart - benefit greatly from higher levels of this vital nutrient.
Vitamin E Is Good for the Heart
Because vitamin E is fat-soluble, its antioxidant action occurs mainly on lipids, and it appears to play an especially important role in limiting the oxidation of LDL-cholesterol ("bad cholesterol"). When LDL is oxidized, it becomes chemically "stickier," in a sense, and this promotes its accumulation, as plaque, inside our arteries. That, of course, leads to atherosclerosis, a major risk factor for heart disease and stroke. Additional data suggest that vitamin E may also prevent the thickening of blood-vessel walls and at the same time enable them to dilate more easily, thus permitting the freer flow of blood (at a lower blood pressure).3 Improvement in all these conditions favors good cardiovascular health - and in the brain, good cerebrovascular health.
Modest vitamin E supplementation
significantly decreases the risk of
heart attack. Vitamin E was
particularly beneficial for women,
decreasing the risk by 34%.
Vitamin E also inhibits platelet aggregation* and may thus serve to inhibit thrombosis (clot formation), which could lead to a heart attack or stroke by limiting blood flow to the heart or brain. Studies conducted in both men4 and women5 have demonstrated that modest vitamin E supplementation (100 IU/day) for more than 2 years significantly decreases the risk of heart attack. Vitamin E was particularly beneficial for women, decreasing the risk of heart attack by 34%. Interestingly, the risk could be decreased even further - to 53% - in combination with vitamin C supplementation, presumably because of vitamin C's ability to regenerate vitamin E in what is known as the "antioxidant network."
*Inhibition of platelet aggregation is generally considered to be good, and agents that have this effect are called anticoagulants, or blood thinners. If two such agents are taken at the same time, however, their effects may be additive. Those who are taking anticoagulant drugs such as heparin or warfarin should consult their doctor before supplementing their diets with large amounts of vitamin E.
Vitamin E - Good for the Whole Body
Vitamin E was discovered 80 years ago, in 1922. Today, this essential nutrient is widely regarded as a vital antioxidant that protects cell membranes and other lipid structures from oxidative damage. Its benefits are widespread, from the heart to the brain to every other tissue in the body. In your quest to improve your quality of life, be sure to pay particular attention to vitamin E. Make sure the amount you ingest is adequate not only to sustain normal cellular functions but also to help protect those two vital organs - the heart and the brain - that need it most.
References
- Ford ES, Sowell A. Serum alpha-tocopherol status in the United States population: findings from the Third National Health and Nutrition Examination Study. Am J Epidemiol 1999;150(3):290-300.
- Morris MC et al. Vitamin E and cognitive decline in older persons. Arch Neurol2002;59:1125-32.
- Traber MG. Does vitamin E decrease heart attack risk: summary and implication with respect to dietary recommendations. J Nutr 2001;131:395S-397S.
- Rimm EB et al. Vitamin E consumption and the risk of coronary heart disease in men. N Engl J Med 1993;328:1450-6.
- Stampfer MJ et al. Vitamin E consumption and the risk of coronary heart disease in women. N Engl J Med 1993;328:1444-9.
Dr. Jensen is a cell biologist who has conducted research in England, Germany, and the United States. He has taught college courses in biology and nutrition and has written extensively on medical and scientific topics.