Your Brain on Vitamin E

 

Ok, everyone knows vitamins are good for you, yada, yada. And most people believe they are getting a sufficient amount in their diets. Yet every nutritional analysis I run comes up short on more than one vitamin. If my clients are a representative sample, then nobody in this country is eating right. 

But my clients are not a representative sample. Many of them suffer from some type of depression. While B-complex vitamins are the ones best known for their impact on mental health, I have been noticing an even stronger trend among depressed persons and those with age-related cognitive decline toward very low levels of vitamin E. Wondering what's up with that, I began combing the research literature on vitamin E and brain health. I found several interesting things. 

Prior to 2004, experimental studies relating to these issues used only one fraction of the vitamin E spectrum, alpha tocopherol. What's worse is that they often used dl-alpha tocopherol, a synthetic form of the vitamin which has no antioxidant ability and shows extremely low bio-availability. Another form used was alpha-tocopherol acetate, also showing no antioxidant activity. Needless to say, the authors usually reported no benefit to vitamin E supplementation. Curiously, when alpha-tocopherol acetate was used, authors reported no benefits even when benefits occurred. 

One such report was a subpart of the Women's Health Study which began in 1998 and included 6,377 women. The authors concluded that vitamin E supplements provide no mental benefits among healthy older women. They failed to report in their conclusion the response to supplementation among high risk women in the group. These were the women who had the lowest levels of vitamin E in their diets, and those who exercised less than once per week. They showed significantly less cognitive decline over four years than those in the placebo group. Not bad for a relatively inactive molecule. 

Since 2004 there has been more interest in the rest of the vitamin E family. Membership includes alpha, beta, gamma, and delta species of both tocopherols and tocotrienols: eight family members total in all natural food sources of vitamin E. Members with the highest antioxidant activity are beta-, gamma- and delta-tocotrienols. Most importantly, as far as the brain is concerned, these are powerful protectors against lipid peroxidation. This means they protect the fatty sheath that surrounds the axons of brain cells as well as the lipid bilayer that forms the cells' membranes. 

But vitamin E's protection is not just through inhibiting oxidation. In 2004 researchers at Ohio State University Medical Center reported that alpha-tocotrienol blocked stroke-induced neurodegeneration in mice between 12 and 30 times more effectively than did alpha-tocopherol. That same year researchers at Kyoto University's Department of Pharmacology reported that a vitamin E mixture containing alpha-tocopherol and three of the tocotrienols significantly inhibited neuronal cell death from several known neurotoxins. Alpha-tocopherol alone did not. In addition, alpha-tocotrienol prevented DNA cleavage and morphological changes in the brain cell nucleus. 

Alpha-tocopherol in its natural form (not dl-alpha or tocopherol acetate) provides some benefits of its own. Although a weak antioxidant compared to its tocotrienol brothers, it has been shown to suppress or delay tau protein pathology in mice the same pathology seen in Alzheimers patients. 

According to two prospective human population studies, it appears to prevent or delay symptoms of emotional depression in men but not in women. However, in a study of 381 female nurses, low plasma levels of alpha tocopherol appeared to be associated with depression, as did high levels of lipid peroxidation. In a smaller Australian study middle-aged adults of both genders were found to have plasma levels of alpha tocopherol inversely related to depression scores. 

What emerged of most interest in two of these studies was that plasma alpha-tocopherol levels were independent of diet. Depressed people, eating the same amount of vitamin E, end up with lower amounts in their blood. Perhaps it is being used up battling the higher than normal amount of lipid peroxidation seen in depressed subjects. To me this indicates a need for much higher intakes of vitamin E for those suffering from depression than the usual recommended amount. 

But what should that amount be? In 1968 the Food and Nutrition Board offered its first Recommended Daily Allowance of vitamin E as 30 IU (international units), which is equivalent to 20 mg. This is a hefty dose. Consider that it takes about three quarters of an 8-ounce cup of olive oil, or almost a pound of peanuts, to get this much vitamin E. So wanting to be more practical, I presume, the RDA was lowered to 22 IU (15 mg) in 2002. Yet according to Prof. Max Horwitt, Ph.D., who spent 15 years serving on the Food and Nutrition Board's RDA committees, the average adult daily intake of vitamin E, without supplementation, appears to be about 12 IU (8 mg). 

Tocopherols (mild antioxidants) are found predominantly in corn, soybean and olive oils. And we consume a lot of this. Tocotrienols (strong antioxidants) are particularly rich in palm, rice bran and barley oils. When was the last time you ate some rice bran and barley oil? My point is that even if we are getting 12 to 22 IU in our diet, we are probably getting a less than optimal balance between the two halves of the E family. 

Since a major role of vitamin E is to inhibit lipid peroxidation, being more powerful in this role than other fat-soluble vitamins, the amount you need depends on the amount of polyunsaturated fats (PUFAs) in your diet. The more PUFAs you eat, the more vitamin E you need. (Major sources of PUFAs include sea fish and plant oils. Other sources include nuts, seeds, vegetables and egg yolk.) So it would be wise to take in enough vitamin E to keep not only these dietary fats from oxidizing, but your brain (and other cells) as well. 

How much is too much? Toxicity studies tested levels of 800 IU per kilogram of body weight daily for five months, and found no harm. This works out to about 60,000 IU daily for an average adult, or well over a thousand times whatever RDA is currently in vogue. Since you would be hard pressed to get this much from either food or supplements, don't be afraid to supplement, especially if you are experiencing depression or are concerned about declining brain function.