Thursday, March 17, 2005

To E or Not To E, Revisited

Another study weighs in on the usefulness, and possible risks, of taking vitamin E supplements. I poo-poo'ed the study last November. This time I'm all ears.

That pill to the right contains vitamin E as alpha-tocopherol, and only alpha-tocopherol. I think it's time for me to kiss it goodbye. (My! It's hard to smooch a pill.)

Here's what the researchers found:
People (at least 55 years old with either vascular disease or diabetes) who took 400 IU vitamin E/day (natural, not synthetic) experienced about the same rate of cancer incidence, cancer death, and major cardiovascular events than did those taking placebo. Those taking vitE experienced a greater incidence of heart failure.

Here's what people may take away from this:
I'm wasting my hard earned cash on these vitE supplements. They aren't going to keep me from getting cancer or heart disease. Fercrissakes, they might cause it!

Here's why I think these researchers are on to something:
Unlike the study (retrospective, meta-analysis) released last November that found an association between early demise and ingestion of 200 IU vitE, this study (prospective, placebo-controlled, randomized) controlled for most of the issues I had with the former study:
  1. We have more confidence that participants actually took the 400 IU vitE: random blood tests were administered at 2 years to measure vitE levels.
  2. It controlled for the effect of a participant's belief that the pill was "doing something", i.e. the placebo effect.
  3. By randomizing, it controlled for the confounding factor: reasons why people take vitE in the first place. (Example: Those with heart disease might be more inclined to take vitE, for its advertised heart benefits, than healthy people. Because of their pre-existing ailment, they might also be more apt to die of heart disease than a healthy person. Did the vitamin have anything to do with it?)
  4. It was statistically powerful: 7000+ participants studied for 7 years.
Of course, these findings can only ever apply to people who already have heart disease or diabetes, since those were their subjects. I don't have heart disease or diabetes (that I know of). Still, is this enough for me to ditch my vitamin E pills? Not yet. Rather, not exactly.

In my previous post, I pointed out that vitamin E is actually a complex, much like vitamin B complex, with 8 components. This study had participants ingest a relatively high amount of only one of those 8 components: alpha-tocopherol. It's been my understanding that vitE pills containing ONLY alpha-tocopherol may be risky since they could displace absorption of the other 7 vitE components, not to mention absorption of other unnamed fat-soluble antioxidants. (The researchers noted this as a possible mechanism for their findings, along with the possibility that the vitamin may have been acting in a pro-oxidant, rather than anti-oxidant, manner.)

Also, intake from foods high in vitamin E seem to perform better in studies than vitamin E supplements, leading one to believe that there are components in say, nuts, other than alpha-tocopherol, that are causing colon cancer cells to self-destruct. (Gamma-tocotrienol, part of the vitE complex not found in the typical supplement, is gaining a pretty good reputation for blasting breast cancer cells.)

So, will I continue to take vitamin E? Yes, but only in a mixed form ("mixed tocopherols and tocotrienols"), and nothing more than 100 IU/day. (100 IU vitE = 67 mg vitE)

By the way, if you want to shun the pill altogether, 50 raw almonds will give you the current Dietary Reference Intake (DRI) of 15 mg (22 IU) for vitE, along with a nice dose of the other 7 vitE components ... for about 380 calories (you can see why I take the pill).

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