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The latest fat-blocking craze might have some validity to it. Chitosan -- a non-digestible fiber derived from shellfish is definitely an amazing substance. It has been used to clean up oil spills and it can work the same way in the body. But the danger is that it absorbs all fat soluble substances indiscriminately, including vitamins E, A, K and D as well as carotenoids and essential fatty acids. Dr. David G. Williams, Editor of the health newsletter Alternatives, says that after a few short weeks of taking the chitosan, you will likely begin to see the negative effects of developing deficiencies of those substances, such as dry skin, impaired night vision, and bruising easily. Longer-term effects may creep up on you much later, such as increased risk of osteoporosis, circulation problems, macular degeneration, heart disease and even cancer.

As someone with a former eating disorder, I fear that this news may fall on deaf ears. I know how strong the desire to lose weight can be and surely would have over used chitosan had it been available to me during the course of my disease. For those who insist on using chitosan, the following strategies might forestall some of the effects mentioned by Dr. Williams:

1. Never take chitosan within an hour before or after taking supplements.
2. Reserve chitosan only for days when you’ve eaten three full meals and will be eating more than you should, perhaps for holiday and social events.
3. Never take chitosan if you’ve been skipping meals.