Vitamin E

One of my goals in the coming weeks is to get 100% of the RDA for vitamin E from food sources, so I thought I’d write a bit about what vit E is, what it does and where to get it. I have used a wonderful resource, the website World’s Healthiest Foods, for most of the information below, but check out the site for more on this and all other matters relating to food and health. Other information came from Wikipedia, the USDA Food and Nutrition Information Centre, the Linus Pauling Institute of Micronutrient Research for Optimum Health and Patrick Holford’s New Optimum Nutrition Bible (2004).

Vitamin E: What it is

Vitamin E is one of the fat-soluble vitamins (the others being A, D, and K – to remember them, ADEK, you can use the mnemonic All Dogs Eat Kidneys; the other vitamins, B and C, are water-soluble).

Vitamin E is actually not one substance but a family name of eight different, related substances. The eight naturally occurring members of the vitamin E family are made up of tocopherols and tocotrienols, both of which come in alpha, beta, gamma and delta varieties. Alpha-tocopherol has the highest bioavailability and is the most studied of the eight members of the family. It should be noted that the majority of clinical studies into the effects of vitamin E have used synthetic alpha-tocopherol, but this may not be a good indicator of the full range of effects of dietary vitamin E, because increasingly, unique and individual functions are now being recognised for the other family members. To confuse matters further, levels of some of the other members of the group are reduced in the blood by alpha-tocopherol supplementation.

Vitamin E: What it does

• Vitamin E is thought to be one of the most important anti-oxidants in the body, preventing free radical damage and protecting cell membranes. Other important anti-oxidants include vitamin C, glutathione, selenium, and vitamin B3.
• It protects the skin from UV rays
• Alpha-tocopherol (but not gamma-tocopherol) has been shown to significantly reduce the risk of bladder cancer, whether ingested from food or supplements. Bladder cancer is four times more common in men than women, being the fourth leading cancer killer in men.
• In contrast, gamma-tocopherol (not usually found in supplements) but not alpha-tocopherol (which is) has been shown to inhibit prostate cancer cell proliferation. These effects appear to be even greater when combined with other forms of vitamin E, such as delta-tocopherol (also not usually found in supplements). This emphasises the importance of getting vitamin E from food sources and not just supplementation, particularly for men.
• Food sources of vitamin E, but not supplementation, have also been shown to be protective against Alzheimer’s disease.
• Vitamin E may also play a part in cholesterol reduction, cardioprotection, immune function and cell signalling.

Vitamin E: How much do you need?

Too Little

Absolute vitamin E deficiency is rare, and tends to occur only in people with digestive diseases that prevent its absorption or genetic mutations that affect the proteins responsible for vitamin E transport. Symptoms of deficiency generally include neurological damage resulting in peripheral neuropathies. Subclinical deficiencies may result in reduced libido, easy bruising, slow wound healing, quick to fatigue and reduced fertility. Around 90% of American adults are estimated not to meet even the minimal RDA requirement for vitamin E (below).

Too Much

It is possible to get too much vitamin E though. Like all the fat-soluble vitamins, if you take in more than you need, it can be stored in body fat, thus building up over time. It is very unlikely that this will happen through dietary intake alone. Symptoms of vitamin E toxicity include severe influenza, malaise, fatigue and intestinal problems. Imbalances of vitamin E and vitamin K (high E, low K) can cause clotting problems, and people taking anticoagulants (e.g. warfarin) or anti-platelet medications should not supplement with vitamin E because of the risk of prolonged bleeding and impaired clotting following an injury. Some doctors also recommend stopping vitamin E supplementation a month before any surgical procedure, for the same reason.

In 2000, the Food and Nutrition Board of the Institute of Medicine established a tolerable upper intake level (UL) of 1,000 mg/day of alpha-tocopherol in any form as the highest dose unlikely to result in hemorrhage in almost all adults.

Recent research has suggested a possible connection between high levels of vitamin E in pregnancy and congenital heart defects in infants. This possibility requires much more thorough and stringent investigation, but to be on the safe side, pregnant women might want to avoid vitamin E supplements.

Just Right

The current RDA for adults is 15 mg per day. This is the amount needed to prevent deficiencies in most people. Patrick Holford recommends an optimal intake of around 300 mg per day. The Linus Pauling Institute recommends about half of this – 134 mg (200 IU) per day for protection against chronic diseases including heart disease, stroke, neurodegenerative diseases, and some types of cancer.

Supplementation:

The amounts of alpha-tocopherol required to achieve these optimal levels are unlikely to be achieved by diet alone. The Linus Pauling Institute, who recommend 200 IU daily of alpha-tocopherol note that supplements containing 200 IU of d-alpha-tocopherol are often as expensive as supplements containing 400 IU of d-alpha-tocopherol, a less expensive alternative may be to take 400 IU (268 mg) of d-alpha-tocopherol every other day.

It is generally thought to be preferable to take a supplement made from natural (d-alpha tocopherol) rather than synthetic (dl-alpha tocopherol) vitamin E. Also, although less common, some supplements now contain a mix of tocopherols.

Vitamin E supplements are unlikely to be absorbed unless taken with food, which should contain some fat.

Medications that prevent fat absorption (for example, some weight loss products) may reduce vitamin E absorption also.

Good Food Sources

All eight naturally-occurring forms of vitamin E are found in food, but the proportions vary. This table, from the Linus Pauling Institute, gives some examples:

Food	Serving	Alpha-tocopherol (mg)	Gamma-tocopherol (mg)
Olive oil	1 tablespoon	1.9	0.1
Soybean oil	1 tablespoon	1.1	8.7
Corn oil	1 tablespoon	1.9	8.2
Canola oil	1 tablespoon	2.4	3.8
Safflower oil	1 tablespoon	4.6	0.1
Sunflower oil	1 tablespoon	5.6	0.7
Almonds	1 ounce	7.4	0.2
Hazelnuts	1 ounce	4.3	0
Peanuts	1 ounce	2.4	2.4
Spinach	½ cup, raw	0.3	0
Carrots	½ cup, raw chopped	0.4	0
Avocado (California)	1 fruit	2.7	0.4

Some of the best food sources

• Excellent sources of vitamin E include mustard greens, turnip greens, chard, and sunflower seeds.
• Very good sources of vitamin E include almonds and spinach.
• Good sources of vitamin E include collard greens, parsley, kale, papaya, olives, bell pepper, brussels sprouts, kiwifruit, tomato, blueberries, and broccoli.

The World’s Healthiest Foods website calculates the best food sources of a nutrient not just on their absolute content of the vitamin, but taking into account how much you’d have to eat to get the amount and the calorie content of that serving size. Based on the serving size, they calculate what they call nutrient density – the amount of vitamin E in the serving per calorie.

The following table, from the website, shows serving sizes and vitamin E content for these foods.

World’s Healthiest Foods ranked as quality sources of: vitamin E
Food	Serving Size	Cals	Amount (mg)	DV (%)	Nutrient Density	World’s Healthiest Foods Rating
Mustard greens, boiled	1 cup	21.0	2.81	14.1	12.0	excellent
Swiss chard, boiled	1 cup	35.0	3.31	16.6	8.5	excellent
Spinach, boiled	1 cup	41.4	3.74	18.7	8.1	excellent
Sunflower seeds, raw	0.25 cup	205.2	18.10	90.5	7.9	excellent
Turnip greens, cooked	1 cup	28.8	2.48	12.4	7.8	excellent
Almonds, dry roasted	0.25 cup	206.0	8.97	44.9	3.9	very good
Collard greens, boiled	1 cup	49.4	1.67	8.3	3.0	good
Kale, boiled	1 cup	36.4	1.11	5.6	2.7	good
Papaya	1 each	118.6	3.40	17.0	2.6	good
Olives	1 cup	154.6	4.03	20.1	2.3	good
Bell peppers, red, raw, slices	1 cup	24.8	0.63	3.1	2.3	good
Brussel sprouts, boiled	1 cup	60.8	1.33	6.7	2.0	good
Kiwifruit	1 each	46.4	0.85	4.3	1.7	good
Tomato, ripe	1 cup	37.8	0.68	3.4	1.6	good
Blueberries	1 cup	81.2	1.46	7.3	1.6	good
Broccoli, steamed	1 cup	43.7	0.75	3.8	1.5	good

Getting the most bang for your buck

High-temperature cooking methods, especially frying, destroy vitamin E, as does factory processing. For example in wheat, most of the vitamin E is found in the germ layer. Commercial processing of wheat into bread, baked goods and pastas removes about 90% of the vitamin E content. Another source of vitamin E loss is exposure to air, and vegetables oils like olive oil, sunflower seed oil, and peanut oil should be kept in tightly capped containers to protect their vitamin E content.

Other inhibitors include air pollution, the birth control pill, an excessive intake of refined or processed oils and some medications, including anticonvulsant drugs (like Dilantin ™) and cholesterol-lowering drugs (like probucol, cholestyramine, clofibrate, colestipol, and gemfibrozil).

On the other hand, taking vitamin E at the same time as vitamin C and selenium may increase its benefits as it works in conjunction with these anti-oxidants.