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Vitamins & Minerals
Vitamin E is an antioxidant that protects cell membranes and other fat-soluble parts of the body, such as low-density lipoprotein (LDL; “bad” cholesterol) cholesterol, from damage.
Immune Function in Elderly People
How to Use It
The recommended dietary allowance for vitamin E is low, just 15 mg or approximately 22 IU per day. The most commonly recommended amount of supplemental vitamin E for adults is 400 to 800 IU per day. However, some leading researchers suggest taking only 100 to 200 IU per day, since trials that have explored the long-term effects of different supplemental levels suggest no further benefit beyond that amount. In addition, research reporting positive effects with 400 to 800 IU per day has not investigated the effects of lower intakes. For tardive dyskinesia, the best results have been achieved from 1,600 IU per day, a large amount that should be supervised by a healthcare practitioner.
Where to Find It
Wheat germ oil, nuts and seeds, whole grains, egg yolks, and leafy green vegetables all contain vitamin E. Certain vegetable oils should contain significant amounts of vitamin E. However, many of the vegetable oils sold in supermarkets have had the vitamin E removed in processing. The high amounts found in supplements, often 100 to 800 IU per day, are not obtainable from eating food.
Severe vitamin E deficiencies are rare. People with a genetic defect in a vitamin E transfer protein have severe vitamin E deficiency, characterized by low blood and tissue levels of vitamin E and progressive nerve abnormalities.
Low vitamin E status has been associated with an increased risk of rheumatoid arthritis and major depression. Women with preeclampsia have been found to have lower blood levels of vitamin E than women without the condition.
Very old people with type 2 diabetes have shown a significant age-related decline in blood levels of vitamin E, irrespective of their dietary intake.
Vitamin E toxicity is very rare and supplements are widely considered to be safe. The National Academy of Sciences has established the daily tolerable upper intake level for adults to be 1,000 mg of vitamin E, which is equivalent to 1,500 IU of natural vitamin E or 1,100 IU of synthetic vitamin E. In a double-blind study of healthy elderly people, supplementation with 200 IU of vitamin E per day for 15 months had no effect in the incidence of respiratory infections, but increased the severity of those infections that did occur. For elderly individuals, the risks and benefits of taking this vitamin should be assessed with the help of a doctor or nutritionist.
In contrast to trials suggesting vitamin E improves glucose tolerance in people with diabetes, one trial reported that 600 IU per day of vitamin E led to impairment in glucose tolerance in obese people with diabetes. The reason for the discrepancy between reports is not known.
In a double-blind study of people with established heart disease or diabetes, participants who took 400 IU of vitamin E per day for an average of 4.5 years developed heart failure significantly more often than did those taking a placebo. Hospitalizations for heart failure occurred in 5.8% of those in the vitamin E group, compared with 4.2% of those in the placebo group, a 38.1% increase. Considering that some other studies have shown a beneficial effect of vitamin E against heart disease, the results of this study are difficult to interpret. Nevertheless, individuals with heart disease or diabetes should consult their doctor before taking vitamin E.
A review of 19 clinical trials of vitamin E supplementation concluded that long-term use of large amounts of vitamin E (400 IU per day or more) was associated with a small (4%) but statistically significant increase in risk of death. Long-term use of less than 400 IU per day was associated with a small and statistically nonsignificant reduction in death rates. This research has been criticized because many of the studies on which it was based used a combination of nutritional supplements, not just vitamin E. For example, the adverse effects reported in some of the studies may have been due to the use of large amounts of zinc or synthetic beta-carotene, and may have had nothing to do with vitamin E. It is also possible that long-term use of large amounts of pure alpha-tocopherol may lead to a deficiency of gamma-tocopherol, with potential negative consequences. For that reason, some doctors recommend that people who need to take large amounts of vitamin E take at least part of it in the form of mixed tocopherols.
Interactions with Supplements, Foods, & Other Compounds
Patients on kidney dialysis who are given injections of iron frequently experience “oxidative stress.” This is because iron is a pro-oxidant, meaning that it interacts with oxygen molecules in ways that may damage tissues. These adverse effects of iron therapy may be counteracted by supplementation with vitamin E.
A diet high in unsaturated fat increases vitamin E requirements. Vitamin E and selenium work together to protect fat-soluble parts of the body.
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