Klein and colleagues recruited 29 postmenopausal non-obese women who were healthy.
--The fact that all participants were of a relationship doctors and healthcare professionals might be a problem, because chances are their friends and family are health conscious and take extra care of their bodies, not exactly the "average" American.
--The sample size was only 29, which is hard for me to really consider the results because 29 people is not enough to guarantee reliability. It is valid, however, at least amongst postmenopausal "healthy" women.
--There are perks for participants in medical studies usually. Though this is scientific research and the perks don't affect the outcome, it is important to release that information to avoid unethical implications.
--The study split the 29 women and did a comparison study, with one half taking a resveratrol supplement, which was equivalent to drinking 8 liters of red wine each day.
--The researchers tracked how the insulin controlled blood sugar, but as an uninformed reader, I have no way of knowing how scientific that tracking was and what medical tests were performed. However, the results of the fat, muscles, blood pressure, and cholesterol are valid because the results of this scientific study cannot really be disproved.