Monday, December 29, 2008

Vitamin E for Diabetes

Vitamin E is a term used to describe eight different chemicals performing the same function.

Many physicians and nutritionists typically refer to alpha-tocopherol as if it were the only component of vitamin E, but, the fact is, it's just the easiest form of vitamin E to measure. Vitamin E consists of not just alpha-tocopherol but a total of four "tocopherols" and four "tocotrienols."

Can supplementing with vitamin E help if you have diabetes?

The answer seems to be "it depends."

A study conducted in Israel and published in late 2007 found that taking 400 IU of vitamin E a day (and by "vitamin E," these researchers meant just alpha-tocopherol) could cut your risk of having a heart attack or stroke almost in half if:

You have type 2 diabetes,
You're over 55 years old, and
You have a special set of genes known as the Hp 2-2 genotype.

This means there are some people whose arteries vitamin E can help a lot, and others maybe little or not at all.

In Western societies, only about 36 per cent of the population has the Hp 2-2 genotype. (Scientists haven't measured the genotype in African and Asian populations yet.) The other 64 per cent won't benefit from taking alpha-tocopherol for their hearts.

Vitamin E, however, can have a much more direct effect on diabetes when it's used in "pharmacologic" doses.

An Italian study found that taking 900 mg (that's about 1200 IU) of alpha-tocopherol a day increased the ability of insulin to move glucose into muscle by about 30 per cent in type 2 diabetics. In this study, vitamin E performs better than any oral prescription medication for type 2 diabetes on the market, but....

The problem with taking a vitamin E supplement that's pure alpha-tocopherol at that dosage is that it can interfere with your body's absorption of the other forms of vitamin E (gamma-tocopherol in particular) and actually raise your risk of having a "sudden cardiovascular event."

You can avoid this problem by taking a supplement that contains at least gamma-tocopherol in addition to alpha-tocopherol, and preferably all eight of the chemical forms of vitamin E.

And if you have "just a touch of diabetes," that is, if you've been told you're "borderline diabetic" or if you have metabolic syndrome, consumption of all of the eight chemicals that make up "vitamin E" may be very useful to you.

A Finnish study found that high-level consumption of the four "tocopherols" and four "tocotrienols" that together function as vitamin E might reduce the risk of developing type 2 diabetes by about 30 per cent.

The Finnish scientists also found that high rates of consumption of a related antioxidant, beta-cryptoxanthin, might reduce the risk of developing diabetes by about 40 per cent.

What's beta-cryptoxanthin?

Well, it's not vitamin E, but it has some of the same functions as vitamin E. Beta-cryptoxanthin is chemically similar to beta-carotene.

Beta-cryptoxanthin, like beta-carotene, is a provitamin that the human body can use to make vitamin A. This hard-to-pronounce antioxidant seems to keep LDL cholesterol from changing into plaques and possibly to prevent the progression of arthritis.

And, for reasons scientists can't explain yet, it is associated with lower rates of diabetes. There's not known to be any downside to taking it. It tends to disappear from circulation in people who use large amounts of margarines with plant sterols to lower cholesterol, like Benecol and Take Control.

So what's my recommendation?

Mixed tocopherols and tocotrienols ("natural" vitamin E) is probably more beneficial for most diabetics. 400 IU a day is enough. 1200 IU a day is better. Do not take more than 400 IU a day of any supplement that's solely composed of alpha-tocopherol.

If you use Benecol or Take Control, be sure you get your beta-cryptoxanthan, either from a supplement or from regular servings of avocado, cilantro, serrano peppers, or (in moderation) grapefruit, oranges, or watermelon.

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