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Do Weight Loss Drugs Affect Vitamin Absorption?

I am currently taking the drug Orlistat for weight loss. I take it three times a day with meals. Since it interferes with fat absorption, will it have an effect on my daily multi and antioxidant? I also take coenzyme Q10 and omega-3 fatty acids.

Answer (Published 2/15/2002)

Orlistat, also known as Xenical, was approved for use by the Food and Drug administration for weight loss in 1999. Orlistat reduces the body's absorption of fat from foods, thereby reducing weight and cholesterol. It does this by blocking the action of lipase, an enzyme in the intestine that breaks down fat. As a result the drug interferes with the absorption of fat-soluble vitamins like A, D, and E, as well as other nutrients such as Co-enzyme Q10 that rely on fat for absorption. Since you are taking many of these fat-soluble micronutrients, you will need to make some adjustments to your supplement schedule.

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My antioxidant formula includes fat-soluble nutrients: carotenoids, vitamin E, coenzyme Q10 (CoQ 10), and vitamin D. In addition, omega-3 fatty acids would need to be taken separately from Orlistat. I would suggest that you take the antioxidant, CoQ 10 and omega-3 fatty acids two hours before or after your take your medication. It is fine to take these all at once if that is most convenient for you.

As you may know, I am not a supporter of weight loss medications. My biggest concern with Orlistat is its common side effects: stomach cramping and diarrhea as well as an increase in blood pressure. Additionally, clinical trials found an increased risk for breast cancer. Your physician should have discussed these risks with you.

Many studies with Orlistat have found that at the end of the first year, users achieve an average of a 5-10 percent drop in body weight, along with a reduction in cholesterol and insulin levels. In those who are obese and have other serious health problems such as heart disease and diabetes, perhaps the use of this medication is sometimes justified. I am curious to know if the drug maintains its effectiveness over a longer period of time, and if users are able to maintain their weight loss once they stop taking it. The long-term success rate with most weight loss medications is minimal, and many (remember Phen-Fen), even prove harmful. I still feel that the simple, safe solution to weight loss is to improve your diet and increase your activity.

Andrew Weil, M.D.

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