By Benjamin V. Treadwell, Ph.D.
Without vitamin E, we essentially turn rancid. Vitamin E is fat-soluble, that is, able to penetrate the fatty areas of our tissues. As it does so, it neutralizes toxic oxidants and protects oxidant-sensitive membranes. Thus vitamin E is justifiably known as an antioxidant, and for helping to prevent age-associated increases in oxidative insults to our bodies.
THE EIGHT FORMS OF VITAMIN E
In reality, vitamin E comes in eight different forms, all of which are derived from plants. The eight E’s are divided into two classes:
- The tocopherols consist of 4 types of vitamin E, alpha, beta, gamma, and delta. The features distinguishing each are slight chemical differences (location and number of methyl groups) on its core structure.
- The tocotrienols are virtually identical to the tocopherols in structure, except for the presence of 3 unsaturated bonds (hence trienol). Alpha, beta, gamma and delta tocotrienols are more permeable to cell membranes because of their unsaturated bonds. This chemical difference imparts certain advantages over the less permeable tocopherols.
The most potent antioxidant of the group is alpha tocopherol. For reasons still unknown, this form of E represents the bulk of vitamin E present in our serum. This is puzzling, since the plants we normally consume contain much more gamma tocopherol. Scientists originally speculated that our bodies require high serum levels of alpha tocopherol and have developed mechanisms to retain it. Thus, multi-vitamins almost always contain alpha tocopherol.
It is becoming more evident, however, that all forms of E are important and that they serve very different functions. Laboratory experiments have indicated that gamma and alpha tocopherol may complement one another with respect to antioxidant protection. Alpha tocopherol is most effective at neutralizing oxygen-based free radicals, whereas gamma tocopherol does best with nitrogen-based free radicals. Both types of radicals are destructive to our bodies.
The vitamin E offered on the market is either man-made or isolated from plants. Man-made (or synthetic) vitamin E is designated on the bottle’s label as DL alpha tocopherol. The D and L are isomers or mirror images of each other. Only the D form is representative of the natural vitamin E alpha tocopherol. There is considerable controversy as to whether the L form interferes with the natural D form in the body. Some researchers believe it may be toxic.
Natural vitamin E is usually labeled D alpha tocopherol but almost always contains all 4 tocopherols. Typically, the bottle’s label mentions only D alpha tocopherol because of the expense the manufacturer would incur to assay for the presence and quantity of the other three. The 4 tocopherols are derived from soybean oil or, less commonly, wheat germ. The 4 tocotrienols are usually prepared from extracts of palm oil or rice bran.
Vitamin E deficiency is not common, but it can occur with poor nutrition and/or a problem with absorption of fats. The RDA for vitamin E is 30 International Units (IU) per day for DL and 22 IU/day for D alpha tocopherol. A diet totally devoid of fats can result in a deficiency of E, since some fat is required for absorption from the intestines.
Fragile red blood cells are a common characteristic of E deficiency. Blood cell membranes, normally protected by E, tend to oxidize and rupture easily. Recent studies indicate vitamin E may help in slowing cognitive decline in Alzheimer’s patients, and it may even lower blood pressure and cholesterol levels. Significant evidence also supports the vitamin as important for protecting tissues from the destructive action of oxidants and consequent disease, including heart disease, cataracts, cancer, neurological disorders and disorders of the muscular system. The incidence of these diseases increases with age. Thus it is important to obtain enough E to attenuate the age-associated destructive process.
Vitamin E is more than an antioxidant. Growing evidence supports specific roles for the different forms of vitamin E. For example, recent research demonstrates gamma tocopherol to be capable of blocking the activity of an enzyme involved in producing cellular mediators of inflammation (prostaglandins), which can lead to disease. Other tocopherols, including the more popular alpha, are largely ineffective in this context.
Alpha tocotrienol has now been shown in cell culture experiments to protect cells of the nervous system from the degenerative action created by the overproduction of the neurotransmitter, glutamate. This chemical, better known as monosodium glutamate, is used as a food enhancer and is infamous for its reputation as the agent responsible for the Chinese restaurant syndrome (bad headaches, etc.) in those who consume too much of it. Normally, an excess of this neurotransmitter activates a neurotoxic enzyme (12-LOX). Tocotrienol, in very small amounts, stops this toxic enzyme in its tracks, thus potentially protecting the nervous tissue.
The unique behavior of the different forms of vitamin E helps explain the advice of nutritionists to consume a variety of fruits, vegetables, legumes and grains. All are good sources of the various forms of vitamin E. Grains should preferably be non-refined. The tocotrienols, as well as other micronutrients, are present in the rice bran, which is lost in processing. People on low-fat diets, such as vegans, are often deficient in vitamin E and should consider taking supplements.
How much E should one take, if any? The upper safe limit for D alpha tocopherol is 1,500 IU/day, according to The Institute of Medicine. The major danger in taking high levels of E is its capacity to inhibit the adherence of platelets to the walls of blood vessels. This is positive for cardiovascular health in those with over-active clotting, but too much E can cause bleeding, especially for people taking other anticoagulants, such as aspirin or coumadin. If you are inclined to take vitamin E, 400 IU/day of natural vitamin E is a reasonable target. However, it is advisable to consult with your physician before taking this supplement.
Finally, the E vitamins function as antioxidants only in their reduced, non-oxidized state. In a subsequent newsletter we will describe how the cells of the body maintain these antioxidants in their reduced or active state. We will also describe how the versatile antioxidant, alpha lipoic acid, functions to recycle these and other antioxidants to maintain cellular health as we age.
Substantial progress has been made in understanding the bio- chemistry of the mitochondria – the organelles that power our cells. Similarly, mitochondrial decay is broadly recognized as playing a central role in the aging process. However, much less is known about effective nutritional approaches to maintain and promote mitochondrial health.
A recent literature review in Canada has evaluated the effects of a wide variety of substances that are reported to produce positive effects on the mitochondria. These include coenzyme Q10; other antioxidants, such as ascorbic acid, vitamin E, and lipoic acid; niacin; creatine; carnitine, and some others. For further information, click here.
This Research Update column highlights articles related to recent scientific inquiry into the process of human aging. It is not intended to promote any specific ingredient, regimen, or use and should not be construed as evidence of the safety, effectiveness, or intended uses of the Juvenon product. The Juvenon label should be consulted for intended uses and appropriate directions for use of the product.
Dr. Treadwell answers your questions about Juvenon™ Cellular Health Supplement
QUESTION: Do free radicals serve any useful purpose? Could one overdo their neutralization by taking too many antioxidants?
J. S., Maryland
ANSWER: Despite all the negative press for free radicals, they are involved in some cellular reactions necessary for good health. For example, free radicals are involved in some enzyme catalyses that are dependent on vitamin B-12. The danger for most people is taking too few antioxidants, but it is possible to take too many.
Our bodies require different amounts of nutrients depending on age, genetic constitution, physical condition, level of stress, and metabolism. Until more solid research is done, I recommend a little experimenting on yourself to determine the optimum nutrients for your particular body type. In addition to my daily Juvenon tablets, I do think it is safe to take a multi-vitamin, CoQ10, vitamins B, C and E, and calcium-magnesium supplements each day…. but not in excess. Of course, it is always a good idea to consult with your health professional before starting something new.
Benjamin V. Treadwell, Ph.D., is a former Harvard Medical School associate professor and member of Juvenon’s Scientific Advisory Board.