DEAR DR. ROACH: I read the letter from the man who took niacin to lower his cholesterol, which resulted in diabetes. I am not sure if you are aware that red yeast rice, which I have been taking, is supposed to reduce cholesterol. To my knowledge, it has no side effects. My doctor said my last tests were good. You might mention this to people as a way of reducing cholesterol. They can buy it over the counter. -- J.D.

ANSWER: Red yeast rice is a fermented rice product that has been used in China to promote “blood circulation.” One well-done but short study from UCLA showed that red yeast rice does indeed lower cholesterol with very few side effects. However, there are several issues that must be considered before recommending the product.

The first is that a chemical analysis of red yeast rice shows that it contains monacolin K, the very same active ingredient in lovastatin, one of the statin drugs. Although there are other compounds in red yeast rice as well, many experts think its primary effectiveness is through the same enzyme that the statins work on, which would imply that red yeast rice has risks similar to all the bad side effects of statins, including increased blood sugar and muscle aches.

  Secondly, there have been no long-term safety studies of red yeast rice that would confirm or deny that implication. 

  The last is the same issue I bring up with any supplement: Most supplements are not standardized or independently tested, and contents may vary dramatically. The amount of monacolin K varied from 0.1 mg per capsule to over 10 mg, depending on the batch and manufacturer. Also, many of the brands tested contained citrinin, a fungus-derived kidney toxin.

  Because of the 100-fold potential variability in effectiveness, potential for toxicity and lack of long-term safety studies, I can’t recommend red yeast rice for general use.