CLA – CONJUGATED LINOLEIC ACID:
The Fat that keeps us Thin
by Lynn Hinderliter CN, LDN
The national obsession with weight continues, with less and less (or perhaps more and more?) success. Despite the fact that more Americans know about healthy diets and the importance of exercise, in the 1980s the amount of weight gained in the U.S.A. would average out to 8 lbs for each and every person!The problem is so widespread that 2 out of 3 Americans qualify as overweight, and that fact carries with it certain health implications, such as atherosclerosis and other heart problems. Americans started fighting fat by limiting their intake of fats from dairy and meat, but did not realize that when they ate snack foods labeled “fat-free”, the fat was usually replaced by sugar for taste and mouth feel, and sugar which is not burned right away for energy is stored in the body as fat – thus compounding the problem every bit as much as fat itself. Add diabetes to the list of health risks.
An intriguing new nutrient is now being investigated for its effect on controlling fat levels in the body, and interestingly, it is itself a form of fatty acid, present in our diet at highest levels in beef and dairy products. It is called CLA (Conjugated Linoleic Acid), and scientists have come to its use for conditions of overweight by a roundabout route. Dr. Pariza has been studying this substance since 1979, though he did not even identify it until 1987. One day at the University of Wisconsin-Madison, he got into a discussion with another scientist, Dr. Cook, who was working on the problem of weight loss in young stock and chicks under disease conditions. This is of great concern to farmers, for the weight gain of their animals obviously contributes to their income.
When a young animal becomes ill, it loses weight and muscle tissue because the activation of its immune system causes the body to produce hormones called cytokines. These not only cause fever and pain, but are involved in the weight loss which can accompany a severe disease state. CLA appears to have an effect on how these hormones operate in the body, because injecting sick rats with CLA produced a group weighing the same as the non-CLA-supplemented control group, but with a higher muscle mass. In another study : after 28 days the rats consuming CLA had 58% less body fat ( 10.13 versus 4.34) than the control group. They also ended with approximately 1% more muscle, though the weights of both groups were the same since muscle weighs more than fat. Those running the study were also interested to note that the animals required less food, by a factor of almost 30%.
In July of 1997, therefore, the first test was run to see whether humans would experience the same kinds of results using CLA. The subjects using CLA lost a statistically insignificant 5 pounds of weight, but the percentage of body fat went down by 25 to 20 %, or from 21.3 to 17. The study used an equal number of men and women. This is not to suggest, of course, that CLA may be a “miracle pill” , because nothing can replace the effects of a healthy diet and proper exercise, but it does place it on a list of nutrients which may have helpful anti-fat properties.
Research in 2003 has also found a role for CLA in controlling appetite after weight loss, so that those who have painstakingly lost their weight do not regain it. The full report is in RESOURCES.
It is also interesting to note that the amount of CLA in our diets has dropped, not only because we are avoiding high fat meats and dairy products, our main source of the nutrient, but also because meat and dairy products nowadays contain less of it to start with. This is because cows and steers are no longer fed a natural grass based diet, but a more “efficient” type of composite feed: in 1994, some scientists noted that meat from Australian cattle have 3 or 4 times as much CLA as American animals, probably because of the feeding differences. This lack of CLA may actually hinder the efforts of some people to lose weight, since CLA nutrition means less fat and more protein in our bodies.
The amount of research being done on this essential fatty acid and its role in atherosclerosis, osteoporosis and cancer is increasing rapidly.
Look carefully at the labels on supplements you may want to buy to make sure you are buying a significant amount of CLA: I have come across some pretty shifty labeling. The amounts used in the human study were 1200 mgs per day, and it takes about 3 weeks to begin to see results. Both Dr. Pariza and Dr. Cook take CLA themselves, and feel they benefit from its use. They consider it a “Quiet Blessing” , saying they feel it is blocking dangerous fat and striving to keep their blood vessels clear. Its most effective action is in preventing the accumulation of body fat, and in preventing relapse once people have lost weight.A 2006 study states “Our present findings indicate that CLA has the potential to be a safe and economically feasible dietary supplement that could serve as an alternative medical approach to preventing bone loss associated with inflammation during aging” (Md Mizanur Rahman in the Journal of Nutritional Biochemistry (doi: doi:10.1016/j.jnutbio.2006.08.002).
Dr. Pariza himself has been taking 3 to 4 grams of CLA daily since it came on the market in 1996, and says it has definitely arrested his middle age spread problem: those of us who are experiencing that unpleasant effect of advancing years might try adding this supplement to achieve the same results.
Interestingly, in a 1999 interview with Victoria Dolby, Dr. Pariza is very excited about the anti-cancer properties he is discovering in connection with CLA, most particularly breast cancer: French researchers have shown a seven-fold lower level of breast cancer in women with an elevated CLA level versus those with lower levels. Since there is a definite connection between fats and breast cancer, this makes sense.
Additionally, an October 2005 study( published in the October 2005 American Journal of Clinical Nutrition) , shows CLA has a protective effect against colon cancer. This was a mega 15 year long study, involving over 60,000 women aged between 40 and 76.
During the almost 15 year period, 798 of the women developed colorectal cancer. The researchers found that those with the lowest risk of developing colorectal cancer were the women who consumed 4 servings or more of high-fat dairy foods per day. The women who consumed less than 1 serving per day had the highest risk. Each increment of 2 servings of high-fat dairy foods per day resulted in a 13 percent reduction in colorectal cancer risk. In addition, the greater the CLA intake, the less the risk of colorectal cancer.
The researchers concluded that high intakes of high-fat dairy foods [and CLA] may reduce the risk of colorectal cancer.
If you want to the protective effect of CLA without the high fat dairy foods, consider a supplement – but as mentioned above, be careful in your choice!
CLA and Weight Loss – http://www.cla-conjugated-linoleic-acid-tonalin.com/journalofnutrition.pdf
Help from CLA to prevent weight regain – http://www.nature.com/cgi-taf/DynaPage.taf?file=/ejcn/journal/v57/n10/abs/1601684a.html&dynoptions=doi1064417598
CLA and breast cancer – http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=14988466
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