Freshman 5 may put young women on road to obesity (Reuters)

Reuters - "Freshman 15," the idea that new college students put on 15 pounds of weight in the first year, may be a myth, but young women do gain about five pounds, Canadian researchers report.

As the US population grows, the quest for weight loss supplements expands in concert. Supplement-seekers desire compounds that are effective, affordable, and devoid of the characteristic "jittery" side effects of many weight loss supplements. "CLA" is a group of dietary fats that many impact the body in a counter-intuitive way--eat fat to lose fat?

CLA has many different chemical forms; they are called "isomers" of CLA. There are two different isomers that are commonly found in supplements on the market, cis-9,trans-11 CT) and trans-10,cis-12 (TC).

Furthermore, misleading marketing and labeling of CLA refers to it as a "natural" product of Safflower oil; however, the CLA supplements in stores a chemically manipulated product of safflower oil. The major known truly natural source of CLA comes from the body fat or milk-fat of ruminant animals. For most people, cow milk or beef fat is the n acetyl l cysteine dosage reviews best source; however, goats, sheep and deer are also ruminants and their products contain CLA. The CLA is actually made in these animals by the bacteria in their stomachs and then it is absorbed and added to their own body fat.

The natural form of CLA is mostly the CT form; the lab created form can be either CT or TC, but is usually roughly a 1:1 ratio of each.

Without a doubt, the stuff works in animals-rodents and beef have been studied extensively. With supplementation of CLA, these animals typically may show 1) More lean body mass; 2) Less body fat; and 3) Less fat production in milk; or 4) lower overall weight. Some studies have also shown improvements in lab values associated with diabetes, heart disease, and breast cancer. On the other hand, some animal studies also show increased inflammation and worse outcomes for lab values associated with diabetes and heart disease. So in terms of general health, the results are highly mixed.

In humans, the results are even more ambiguous. Many studies show absolutely nothing, while about 1/3 to show positive effects, including: slightly reduced body fat, slightly increased lean mass or the prevention of weight gain/regain. One recent study (1) gave people a 3.2 g/day of CLA for 6 months, including throughout the holiday season, and the CLA prevented fat gain in the supplemented group. The authors concluded that the supplement may be more useful for prevention rather than treatment. Many, many factors have made the human studies hard to compare to one another though:

- CLA is definitely a long-term supplement; there is no significant evidence supporting it's use for the short term (you need to take it for at least a few months to see an effect, not a few weeks)

- CLA doses are different in every study and are usually decided pretty arbitrarily

- CLA isomers (CT or TC) are given in different proportions in many of the studies, or are not controlled for at all.

Some human studies also show potential inflammatory effects and insulin resistance from CLA supplementation-these effects seem to be caused more by the TC form than the CT form. Remember that TC is only made in significant amounts in the lab, whereas CT occurs naturally in milk products, etc.

In conclusion, the jury is definitely still out on CLA. Researchers are pretty sure that the effects are dependent on the type of CLA you take, CT or TC. Clinical trials do not show significant amounts of weight loss in humans, but is may make you a little leaner and prevent some fat gain. The impact on health and disease is also important to consider; some studies have shown that CLA supplementation increases inflammation and lowers your "good" cholesterol.

CLA is not worth taking unless you really need to get super ripped (especially at $20/3-4 week supply). Your money would be better spent on improving the quality of your diet! On the other hand, if you are determined to take a CLA supplement: 1) try to find one that was extracted from dairy fat (if it exists, it's obscenely expensive); or 2) find one that contains more CT than TC. As of several years ago, these ratios were not listed on the bottle, but now many manufacturers do include the isomer percentages. Remember that no one is checking to make sure the label is accurate, so buy only from supplement makers that you trust!

As with any supplement, research suggests that it works better in conjunction with weight training and a healthy diet, so happy lifting!!!

1. International Journal of Obesity (2007) 31, 481-487. doi:10.1038/sj.ijo.0803437; published online 22 August 2006

Jean Jitomir MS, RD is an experienced nutrition coach, physique competitor, and Exercise Nutrition Ph.D. student. She blogs regularly at:

http://builtnutrition.blogspot.com

Her personal website is:

http://www.jeanjitomir.com