Vitamin E: food sources, functions, side effects and daily dosing
The concept of healthy life is incomplete without vitamins and minerals. Vitamins and minerals are an indispensable component of a healthy, nutritious and balanced diet. Like other vitamins, vitamin E is also required for the normal growth and the maintenance of various body functions. The active components of vitamin E are eight fat soluble compounds called tocopherols and tocotrienols. The most abundant amongst these tocopherols is alpha-tocopherol.
Vitamin E is readily absorbed through small intestine with the help of bile and is transported to the liver. From liver it is sent away to various tissues of body. Since vitamin E is a fat soluble vitamin, it can be stored easily in the fat cells and tissues of body for longer time. This fat soluble nature of vitamin E allows its storage in body, thereby reducing the risks of vitamin E deficiency or depletion.
Food sources of vitamin E
Here are given some of the richest natural sources of vitamin E:
- Vegetable oil such as sunflower oil, palm oil, corn oil and soybean oil are the number one sources of vitamin E.
- Brazil nuts
- Peanut oil
- Turnip green
- Sunflower seeds
- Leafy green vegetables
- Fortified cereals
- Pine nuts
- Peanut butter
- Wheat germ
- Red bell pepper
- Sea foods like shrimps
- Salmon fish
- Swiss chard
- Mustard greens
- Collard greens
- Apple seeds
Functions of vitamin E
Vitamin E participates in many biological functions of the human body. But it is primarily used as an antioxidant inside the body. Vitamin E is the most potent antioxidant among all other vitamins.
Vitamin E as an antioxidant
Vitamin E is a known antioxidant but what is meant by antioxidant? How vitamin E is supposed to behave like an antioxidant? These questions or queries must need to be addressed before understanding the various functions of vitamin E.
Each function that vitamin E performs in body is based upon its antioxidant potential. One who knows about the concept of antioxidants will be able to comprehend the unique functions of vitamin E. Vitamin E protects our body by fighting against certain harmful chemical substances produced in body called “free radicals”.
But what are these free radicals? How does vitamin E remove these free radicals from body? Free radicals are reactive molecular derivatives of oxygen that are produced inside the body in a number of metabolic processes. But many environmental factors like smoke, pollution, radiations and chemicals also induce the formation of oxygen free radicals inside the body.
The presence of these radicals in the normal and healthy body is quite natural and sometimes beneficial for us because these reactive radicals aid our body’s natural immune system by killing the harmful bacteria, pathogens and invader substances that make their entry into the body. But the excess of these free radicals does more harm than good.
These radicals cannot differentiate between the healthy tissue and foreign particles. As a result they begin to attack normal and healthy tissues of body. These radicals are highly reactive because they have unpaired electron. In order to gain electrons, they oxidize healthy cells and cause damage to them.
Eventually the formation of free radical becomes a chain reaction. To stop these radicals from damaging the tissues, vitamin E comes into action. Vitamin E satisfies these electron hungry free radicals by providing them with an extra electron pair. In this way the chain reaction breaks and the free radicals come to peace.
Some of the antioxidant roles of vitamin E are mentioned below:
- Vitamin E prevents heart diseases. Vitamin E cannot cure heart diseases but it can reduce their risk in healthy individuals. Vitamin E through its antioxidant property prevents the oxidation of LDL (low density lipoproteins) cholesterol molecules. LDL is also called bad cholesterol because it gets oxidized very easily by free radicals. This oxidized LDL then deposits in arteries by sticking to their walls, leading to the formation of atherosclerotic plaques in the arteries. These plaques increase the risks of heart diseases by compromising its blood supply. But vitamin E stops this from happening by combating the free radicals.
- Vitamin Eprotects the healthy cells. The lipid cellular membranes are more prone to get oxidized by free radical. But vitamin E protects the cells from damage by limiting their oxidation. The antioxidant effects of vitamin E are highly beneficial for red blood cells which are more susceptible to the damaging effect of oxygen free radicals. So, the severe deficiency of vitamin E might result in breakdown of red blood cells and anemia.
- Vitamin E limits the blood clotting. Blood clots are formed when platelets in blood clump and stick to the arterial walls. But this happens only when the arterial walls are damaged. The normal and healthy arteries do not allow the platelets to stick and clots to form. The walls of arteries are sensitive to the damage caused by toxic free radicals. The damaged arterial walls promote platelet aggregation and clot formation. Vitamin E limits platelet aggregation and clotting by keeping the arteries in healthy state. Apart from this, vitamin E also helps in improving the blood circulation through dilating the blood vessels.
- Vitamin E makes your skin look healthy. Repeated exposure to ultra violet radiation induces the formation of free radicals in the skin layers. These radicals damage the skin tissues, which causes fading of skin tone, wrinkling and aging. Vitamin E stops the radicals from damaging the skin and gives you a fair, beautiful and younger looking skin. Vitamin E is also helpful in fading acne scars. Most of the anti acne topical creams contain vitamin E in them.
- Vitamin E slows down brain aging: The neuronal brain cells are surrounded by protecting myelin sheaths, made of lipids. These protective layers are worn out with age. Vitamin E limits brain aging process by protecting the neuronal cell membranes from the damage of free radicals.
Vitamin E as an immunity booster
Another beneficial aspect of vitamin E is its immunity boosting effect. Vitamin E helps in increasing the number of white blood cells and anti bodies in the body by protecting them from oxidation and damage.
Interactions with other vitamins
Vitamin E improves the availability of oxygen sensitive vitamin A and C by shielding them from the harmful effects of oxygen free radicals.
Side effects of vitamin E
Vitamin E is fat soluble and can be stored in adipose tissue of body. Therefore, the chances of its toxicity are high as compared to water soluble vitamins. Be cautious before taking the supplements of this vitamin, without consulting your doctor, because they can do more harm than good if taken in more than recommended amounts. However, the chances of vitamin toxicity with the consumption of natural food sources are rare or almost impossible. The upper safe limit for vitamin E consumption is 1000 mg per day.
Taking vitamin E more than this amount can cause following complications and side effects:
- Gastrointestinal issues. Overdoses of vitamin E might result in gastrointestinal troubles like nausea, vomiting, abdominal cramps and diarrhea.
- Brain hemorrhages. Vitamin E in recommended doses causes slight dilation of blood vessels. But an overdose of this vitamin causes the rupturing of vessels in brain, resulting in brain strokes and hemorrhages. Brain strokes need to be treated on emergency basis; otherwise they would lead to several other medical complications like paralysis.
- Bleeding. Internal bleeding is one of the serious consequences of vitamin E toxicity. Vitamin E causes thinning of blood by inhibiting the platelet aggregation or clot formation. That is why taking too much vitamin E increases the risks of bleeding. This complication specially occurs in patients taking vitamin E supplements along with other blood thinning or anticoagulant medicines like warfarin. So, you have to be careful before using the vitamin E supplements if you are already taking anticoagulant medicines.
- Birth defects. Vitamin E should be taken with great caution in pregnancy. Studies show that taking vitamin E more than recommended amount in pregnancy has found to be associated with birth defects in fetus.
- Vision problems. Taking too much vitamin E may cause the blurring of vision as well.
- Skin problems. Skin rashes and contact dermatitis is common with the use of topical vitamin E creams especially in people who are allergic to it. Overdoses of vitamin E cause bruises on skin due to its anticoagulant effect.
Recommendations of vitamin E
The RDA values (recommended dietary allowance) are the standard values which tell about the daily recommended intake of vitamin. The RDA value varies according to the age group of person.
The RDA values of vitamin E are:
- For infants: 0-6 months: 4mg/day 7-12 months: 5mg/day
- For children: 1-3 years: 6mg/day 4-8 years: 7mg/day 9-13 years: 11mg/day
- Teens and adults: 14 years and older: 15mg/day Pregnant women: 15mg/day Lactating women: 19mg/day
|Written by:||Michal Vilímovský (EN)|
|Education:||Medical student, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic|
|Published:||March 18, 2014 2:14 AM|
|Next scheduled update:||March 18, 2016 2:14 AM|