The Sept. 6 issue of the Annals Internal Medicine reviews an earlier Lancet article ( Bjelakovic, G et al-Lancet 2004:364;1219-1228) which not only concluded that antioxidants do not prevent GI cancers but may increase the risk. The data clearly did not show cancer reducing benefit form the supplements included (various vitamins and selenium) but the conclusion of possible increased risk seems unwarranted as the Annals reviewer explains in his analysis. The increased risk (R.R=1.06) was found in a fixed-effects model which is said to be used if the data appear to be homogeneous but 7 of the trials seemed to be heterogeneous. The random effects model analysis did not show an increase in all-cause mortality and that type of analysis is usually what is employed with heterogeneous data.
The same review section ( Update in Gastroenterology and Hepatology) includes an article of a RCT evaluating the use of herbal preparation for the treatment of IBS. 208 patients were assigned to receive 1 of 4 regimens. An abdominal symptom score was the endpoint of interest. 2 of the 4 regimens were said to bring about significant improvement in symptoms scores.Both regimens contained peppermint and caraway fruit. The reviewer concludes that practitioners "should consider" these herbal preparations to their armamentarium for IBS. I know there is considerable energy in the efforts to make respectable complementary and alternative medicine but one small RCT seems to me inadequate evidence to include these herbs in your treatment choice bag just yet. (There are a few other small trials using the combination of these two herbs for treatment of "non-ulcer dyspepsia" but are we seeing a type of affirmative action for alternative medicine . FDA approval would not be granted for a prescription medication based entirely on one RCT.)