Lesser known among the vitamin league, vitamin E can cause neurological symptoms, cause muscle weakness and impair balance and coordination. Vitamin E can be lost from foods during preparation, cooking or storage
VITAMIN E is a fat-soluble vitamin that exists in eight different forms. Each form has its own biological activity, the measure of potency or functional use in the body. Alpha-tocopherol is the most active form of vitamin E in humans, and is a powerful biological antioxidant. Antioxidants such as vitamin E act to protect your cells against the effects of free radicals, which are potentially damaging by-products of the body’s metabolism. Free radicals can cause cell damage that may contribute to the development of cardiovascular disease and cancer. Vitamin E, is a fat-soluble vitamin. It protects vitamin A and essential fatty acids from oxidation in the body cells and prevents breakdown of body tissues.
Individuals who suffer from severe malnutrition, genectic defects affecting the a-tocopherol transfer protein and fat malabsorption syndromes, have been the ones suffering from vitamin E difeciency.
Severe vitamin E deficiency results mainly in neurological symptoms such as impaired balance and coordination, and muscle weakness. Children with severe vitamin E deficiency from birth, who are not treated with vitamin E, rapidly develop neurological symptoms. In contrast, individuals who develop malabsorption of vitamin E in adulthood may not develop neurological symptoms for 10-20 years.
Although true vitamin E deficiency is rare, sub-optimal intake of vitamin E is relatively common. Vitamin E can be lost from foods during preparation, cooking, or storage. To retain it, use whole-grain flours and store foods in airtight containers and avoid exposing them to light.
A good food source of vitamin E contains a substantial amount of vitamin E in relation to its calorie content. An interesting study in the US in 1990, revealed that 62.5 per cent of vitamin E in the diets of Americans came from fats and oils, and 12.4 per cent came from meats, poultry, fish, legumes, nuts and soy. Foods that contain small amounts of vitamin E but are not considered good sources can contribute significant amounts of vitamin E to an individual’s diet if these foods are eaten often or in large amounts.
An average Pakistani diet differs in many ways from its American counterpart. We consume oils in greater amount as compared to solid fat. Eggs, dairy products, meat, poultry, fish, nuts and fruits are abundantly taken in the US. In Pakistan, an average individual devours curry with sparse quantum of meat and vegetable in it. This gravy is not good quality food, as it consists of chilies, spices and ghee or oils (saturated fats full of cholesterol). Certainly, this curry (gravy), particularly when consumed with rice, and not with chapatti, is devoid of many essential nutrients and vitamins, including vitamin E.
Still, vitamin E deficiency is rare in humans. There are three specific situations when a vitamin E deficiency is likely to occur. It is seen in persons who cannot absorb dietary fat, has been found in premature, very low birth weight infants (birth weights less than 3 and a half pounds) and is seen in individuals with rare disorders of fat metabolism. A vitamin E deficiency is usually characterized by neurological problems due to poor nerve conduction.
Individuals who cannot absorb fat may require a vtamin E supplement because some dietary fat is needed for the absorption of vitamin E from the gastrointestinal tract. Anyone diagnosed with cystic fibrosis, individuals who have had part or all of their stomach removed, and individuals with malabsorptive problems such as Crohn’s Disease, may not absorb fat and should discuss the need for supplemental vitamin E with their physician. People who cannot absorb fat often pass greasy stools or have chronic diarrhea.
Very low birth weight infants may be deficient in vitamin E. A paediatrician specializing in the care of newborns evaluates and treats the exact nutritional needs of premature infants.
VITAMIN-E AND HEART DISEASE: Preliminary research has led to a widely held belief that vitamin E may help prevent or delay coronary heart disease. Researchers are fairly certain that oxidative modification of LDL-cholesterol (‘bad’ cholesterol) promotes blockages in coronary arteries that may lead to atherosclerosis and heart attacks. Vitamin E may help prevent or delay coronary heart disease by limiting the oxidation of LDL-cholesterol.
Vitamin E also may help prevent the formation of blood clots, which could lead to a heart attack. Observational studies have associated lower rates of heart disease with higher vitamin E intake. A study nurses suggested that the incidence of heart disease was 30 per cent to 40 percent lower among nurses with the highest intake of vitamin E from diet and supplements. The range of intakes from both diet and supplements in this group was 21.6 to 1,000 IU (32 to 1500 mg), with the median intake being 208 IU (139 mg).
A 1994 review of 5,133 Finnish men and women aged 30 to 69 years suggested that increased dietary intake of vitamin E was associated with decreased mortality (death) from heart disease. A small observational study of men who had previously undergone a coronary artery bypass graft found a reduction in the progression of coronary artery atherosclerosis by angiography in those men who took at least 100 IU of a-tocopherol daily.
A randomized, placebo-controlled intervention trial in Great Britain (the CHAOS study) found that supplementing heart disease patients with either 400 or 800 IU of synthetic a-tocopherol for an average of 18 months resulted in a dramatic 77 per cent reduction in non-fatal heart attacks. However, total deaths from heart disease were not significantly reduced.
Chronic renal dialysis patients are at much greater risk of dying from cardiovascular disease than the general population, and there is evidence that they are also under increased oxidative stress. Supplementation of renal dialysis patients with 800 IU of natural a-tocopherol for an average of 1.4 years resulted in a significantly reduced risk of heart attack compared to placebo. In contrast, three other intervention trials failed to find significant risk reductions with a-tocopherol supplementation. One study, which was designed mainly to examine cancer prevention, found that 50mg of synthetic a-tocopherol daily resulted in a non-significant decrease in nonfatal heart attacks in those participants who had had previous heart attacks.
A study followed almost 10,000 patients for 4.5 years who were at high risk for heart attack or stroke. In this intervention study the subjects who received 265mg (400) IU of vitamin E daily, did not experience significantly fewer cardiovascular events or hospitalizations for heart failure or chest pain when compared to those who received a neutral pill.
Researchers suggested that it is unlikely that the vitamin E supplement provided any protection against cardiovascular disease in this study.
VITAMIN E AND CANCER: Antioxidants such as vitamin E help protect against the damaging effects of free radicals, which may contribute to the development of chronic diseases such as cancer. Vitamin E also may block the formation of nitrosamines, which are carcinogens formed in the stomach from nitrites consumed in the diet. It may also protect against the development of cancers by enhancing immune function. Unfortunately, human trials and surveys that tried to associate vitamin E with incidence of cancer have been generally inconclusive.
Some evidence associates higher intake of vitamin E with a decreased incidence of prostate cancer and breast cancer. However, an examination of the effects of dietary factors, including vitamin E, on incidence of postmenopausal breast cancer in over 18,000 women from New York State did not associate a greater vitamin E intake with a reduced risk of developing breast cancer.
Another study of women in the US provided evidence that an increased dietary intake of vitamin E may decrease the risk of colon cancer, especially in women under 65 years of age. On the other hand, vitamin E intake was not statistically associated with risk of colon cancer in almost 2,000 adults with cancer who were compared to controls without cancer. At this time there is limited evidence to recommend vitamin E supplements for the prevention of cancer.
VITAMIN-E AND CATARACTS: Observational studies have found that lens clarity, which is used to diagnose cataracts, is better in regular users of vitamin E supplements and in persons with higher blood levels of vitamin E. A study of middle aged male smokers, however, did not demonstrate any effect from vitamin E supplements on the incidence of cataract formation. The effects of smoking, a major risk factor for developing cataracts, may have overridden any potential benefit from vitamin E, but the conflicting results also indicate a need for further studies before researchers can confidently recommend extra vitamin E for the prevention of cataracts.
DIABETES MELLITUS: a-tocopherol supplementation of individuals with diabetes has been proposed because diabetes appears to increase oxidative stress and because cardiovascular complications (heart attack and stroke) are among the leading causes of death in diabetics.
A recent study found a biochemical marker of oxidative stress to be elevated in diabetic individuals. Supplementation with 600mg of synthetic a-tocopherol daily for 14 days resulted in a reduction in the oxidative stress marker. Studies of the effect of a-tocopherol supplementation on blood glucose control have been contradictory. One study reported improved control of blood glucose levels with supplementation of only 100 IU of synthetic a-tocopherol daily, while studies using 900 to 1,600 IU of synthetic a-tocopherol daily found either minimal or no improvement, respectively. Although there is reason to suspect that a-tocopherol supplementation may be beneficial for individuals with diabetes, evidence from well-controlled clinical trials is lacking.
DEMENTIA (IMPAIRED COGNITIVE FUNCTION): The brain is particularly vulnerable to oxidative stress, which is thought to play a role in the pathology of neurodegenerative diseases, such as Alzheimer’s disease. In a large placebo-controlled intervention trial, supplementation of individuals who had moderate neurological impairment with 2,000 IU of synthetic a-tocopherol daily for two years resulted in a significant slowing of the progression of Alzheimer’s dementia. After Alzheimer’s disease, vascular dementia (dementia resulting from strokes) is the most common cause of dementia.
A case-control study examining risk factors for vascular dementia in elderly Japanese-American men found that supplemental vitamin E and vitamin C intake was associated with a significantly decreased risk of vascular and other types of dementia, but not Alzheimer’s dementia. Among those without dementia, vitamin E supplement use was associated with better scores on cognitive tests.
FERTILITY: Men concerned about their fertility often look for easy alternatives to improve their sperm count. Often times men try to improve their sperm count by researching over-the-counter vitamins, minerals, herbs and dietary supplements. Scientific data regarding many of these alternatives are either lacking or unconvincing. But a few of them, for example selenium, vitamin C, zinc, proxeed and vitamin E do show some promise in improving a man’s fertility potential.
Vitamin E has long been known for its antioxidant effects on cell membranes. Recently there has been some data published about vitamin E’s effect on fertility enhancement. A double-blind, randomized, placebo controlled study conducted in Sheffield, England, showed some promising results. The crux of the experiment was to see the effects of vitamin E in treating men with reactive oxygen species-related infertility. The research showed that consumption of 600mg per day of vitamin E improved sperm function in these patients.
