For people who struggle to manage their weight, the problem of yo-yoing between weight loss and weight regain may have met its match. By now many of our readers are familiar with the dramatic health benefits of conjugated linoleic acid (CLA), a fatty acid that's shown promise as an anticancer agent. In a previous alert I looked at CLA studies and testimonials that showed how CLA may also help replace body fat with lean body mass. But some important questions linger amid these benefits. Last September, the New York Times carried an in-depth article that reviewed the pros and cons of supplementing with CLA. The primary problem cited: Although CLA has been researched for many years, no studies have examined the potential adverse effects in the long-range use of the supplement. Until now, that is. This month, the Journal of Nutrition published a study conducted by a team of scientists from several medical centers in Norway. More than 150 overweight subjects participated in a one-year trial that compared the effects of CLA to a placebo. At the end of the year 134 subjects agreed to sign on for an additional year of open testing, with each subject receiving 3.4 grams of CLA daily. This second phase was specifically designed to assess the safety of CLA in two ways; with clinical chemistry analysis and reports on adverse events from the subjects. Changes in body fat mass (BFM), lean body mass (LBM), body weight and other factors were also tracked. Overall, the subjects had no change in fasting blood glucose. Total cholesterol and LDL were reduced overall, while triglycerides and HDL remained the same. LBM was generally unchanged. Subjects who started out with the highest BFM lost the most body fat during the first year of the study. Significantly, these subjects did not regain any of the fat over the full two-year testing period, avoiding the yo-yoing effects of weight loss and regain. Subjects who took CLA only during the second year lost an average of 3.5 pounds while also reducing body fat. As for safety issues, the researchers found CLA to be well tolerated. A small percentage of mild reactions (mostly gastrointestinal) were reported, and the rate of adverse events decreased during the second year of the study. There are a few caveats concerning this study that should be noted. First: The funding came from Cognis, a company that produces a popular CLA supplement called TONALIN. Second: CLA is not a replacement for the two things that will help people lose weight; regular exercise and a balanced diet free of highly processed foods. You may have noticed the detail above about the subjects who took CLA only during the second year of the study and lost an average of 3.5 pounds overall. That's not an impressive weight loss by any standard. But those subjects did show a body fat reduction. So while CLA isn't a miracle diet pill, some people will find it helpful in addressing body fat. This aspect of CLA is nicely described by Michael W. Pariza, Ph.D., who discovered CLA. Dr. Pariza told WebMD Medical News that people who take CLA in an attempt to lose weight will be disappointed if they don't improve their diet and exercise patterns. Finally, the safety record in the Norway study was generally good, but a few inconsistencies developed that should be noted by dieters (and their doctors) before using CLA. For instance, cholesterol changes were generally positive, but some subjects increased lipoprotein levels. Meanwhile, other subjects had an increase in white blood cells and blood platelet counts. This is a red flag that signals possible inflammation, which could complicate blood vessel health over time. So even though this trial provides safety reassurances, the researchers noted in their conclusions that the association between CLA and heart health is still unclear. As I've mentioned in previous alerts, dietary sources of CLA include butter, beef and whole milk, but only when these foods come from grass-fed cattle. CLA levels drop when cattle are fed grain and hay. And for optimum nutrition from dairy products, raw unpasteurized milk is always far preferable to the pasteurized milk you'll find on most grocery shelves. When Jonathan V. Wright, M.D., wrote about CLA in the November 2000 issue of his Nutrition and Healing newsletter, he noted that supplements of CLA should be taken with a broad range of other fatty acids, such as flaxseed oil, which contains a majority of omega-3 fatty acids, but also omega-6 and omega-9 fatty acids. In addition, vitamin E (as alpha-tocopherol along with other tocopherols) should be taken with any fatty acid supplement to help keep the acids from oxidizing and forming free radicals. A quick side note: Remember that men who are at high risk of prostate cancer should avoid using flaxseed oil, which may encourage growth of prostate cancer cells. In this case, freshly ground flaxseed provides a safe alternative.