Conjugated linoleic acid just might be your ticket to more muscle and less fat.
By George Paige
We are standing on the crest of a wave right now, and that wave is called conjugated linoleic acid (CLA). Just a few years ago, the U.S. Food & Drug Administration (FDA) bestowed Generally Regarded as Safe (GRAS) status on the fat-fighting supplement CLA.
“CLA is one of the few nutraceutical-type supplement ingredients that has received GRAS approval by the FDA,” says Michael Pariza, PhD, one of the leading scientists in the field of CLA. What this means for Joe Obesity—representing nearly one-third of the population in the United States—is that in the near future he’ll feel better about himself for drinking a quart of chocolate milk because it contains CLA. But before CLA hits the food chain, there’s plenty of evidence to show that you shouldn’t wait for the wave; you should paddle out and get some of your own—ASAP.
In the Lab
CLA refers to a collection of fatty acids that are found in meats and milk, and the fact is,
your body needs CLA. Why? The current CLA journey began in 1987, when Pariza—then a researcher at the University of Wisconsin-Madison—discovered that the fatty acid, which was known to exist as far back as the late 1930s, actually had biological activity. Pariza and his associates found that CLA was an anti-carcinogen and were feeding it to mice in an effort to understand how it suppressed tumor growth. They noticed profound changes in the body composition of the mice they were studying. Since then, CLA has continued to show potent cancer-fighting effects in animal studies, but they haven’t been proven in humans. That doesn’t mean that CLA is worthless, though.
In the Weight Room
Multiple studies have shown that CLA helps reduce body fat in obese and overweight populations. But the question has always been this: Though CLA can help the fat guy on the couch go from a size 56 pair of jeans to a size 44, can it help the guy in the gym go from 16% body fat to 10%? A slew of promising research has come to light over the past few years showing that CLA’s greatest potential might be for those who are seriously interested in getting leaner and stronger.
In contrast to this fatty acid’s reputation as a fat burner only for the obese, scientists in Norway conducted a study on healthy subjects who trained in a gym for 90 minutes a day three times a week. At the end of 12 weeks, the group who took CLA lost significantly more body fat than the placebo group. A more recent study showed that CLA is a natural addition for guys who are truly living the Reps! active lifestyle. Researchers at the College of Kinesiology at the University of Sakatchewan in Saskatoon took three groups of strength-trained subjects and gave one group a mix of CLA, creatine and whey protein. The other subjects received either just creatine and whey or a placebo. After five weeks, the group that took all three supplements experienced greater increases in bench-press strength, leg-press strength and lean mass than the other two groups combined.
CLA seems to have similarly synergistic abilities when it comes to burning fat. A study published in the journal Lipids in Health and Disease showed that when CLA was combined with green tea extract (one of the main active ingredients in most fat burner formulations), it led to a decrease in body fat.
CLA could also be a perfect complement to caffeine. While everyone’s favorite stimulant is a potent fat burner, it’s in danger of being overused in the post-ephedra era. After all, there is a limit to how much caffeine your nervous system can handle. The beauty is, caffeine aids fat loss by triggering the release of norepinephrine—a completely different avenue than CLA takes.
“CLA has direct effects on both the fat cell and the skeletal muscle cell,” explains Pariza. “When you eat fat, there are only two things you can do with it: burn it or store it. You burn it in the skeletal muscle and you store it in the fat cells. CLA keeps fat cells from storing fat and stimulates muscle cells to burn fat.”
At the Table
It’s easier than ever to get an efficacious amount of CLA in your diet. First of all, two major reputable brands, Tonalin and Clarinol, supply most of the CLA to manufacturers. One makes CLA from safflower oil and one from sunflower oil—both of which are nearly identical in their molecular structure. Secondly, experts have finally agreed on a daily dosage.
“Three grams a day,” says Pariza. “When we started, we weren’t quite sure, so we were basing it on what we thought could potentially come from your diet if you eat a lot of foods that are high in CLA. It turns out, in clinical trials, three grams a day is the level that seems to produce the maximum effect; if you go up to six or nine grams a day, you’re not getting much more benefit.” It’s clearly not a case of more is better, a not uncommon mindset for many gymgoers.
It used to be nearly impossible to get your CLA from food because the amount of dietary fat you’d need to eat would be counterproductive to trying to get lean. But a few things have changed that make the idea of getting the requisite three grams through food fairly realistic. For one, the nutritional stigma of consuming animal-based fats has slowly gone the way of the rice cake, and most physique-conscious guys have loosened the reins on fat while curbing their carb intake. In fact, adherents of the currently popular Paleo or Primal diets will consume up to 50% of their daily calories from fat (mostly animal sources) while eschewing all grains and consuming less than 100 grams of carbs a day. These so-called “evolutionary diets” also place an emphasis on eating meat and dairy products from grass-fed animals, and studies show that milk from grass-fed cows contains 500% percent more CLA than commercial milk, while beef from pastured animals has 550% more CLA than conventionally raised grain-fed cows.
Pastured meat is a self-fulfilling prophecy when it comes to CLA because grass-fed meat also contains more trans-vaccenic acid (TVA), a trans fatty acid that has been proven to help fight diabetes, obesity and heart disease. (Don’t get thrown off by the word trans fat. Naturally occurring trans fats are much different than the ones you’ve been warned about in margarine and fried foods.) In addition, TVA is a dietary precursor to CLA—meaning that it will convert into CLA in the body. In fact, subjects fed TVA are shown to exhibit more CLA in their system than those who consume the same amount of supplemental CLA.
While the health, environmental and body-altering benefits of consuming pastured meat and dairy products continue to mount, Pariza still recommends supplementing. CLA actually refers to a collection of 28 isomers—compounds that contain the same molecular formulas but different structural formulas. The majority of CLA is composed of two types of isomers, known as cis-9-trans-11 and cis-10-trans-12—or better known as 9/11 and 10/12. The latter seem to be responsible for the beneficial changes in body composition, although both are anti-carcinogens in different ways and a synergy exists between the two. Since the ratios in milk and meat can change depending on feed and the genetics of the animal, Pariza feels that supplements are the best way to guarantee ingesting the optimal ratio.
In the Pipeline
Ultimately, scientists feel that they have just begun to scratch the surface of CLA’s potential. Even though it has been studied vigorously for nearly 25 years, new upsides continue to emerge.
“I’d say one of the most interesting things is the possibility that it has very pronounced effects on the immune system,” says Pariza. “One of the things it does in animals—and there is evidence emerging that it does this in humans as well—is reduce symptoms of asthma. It helps with hypersensitivity reactions, so people who have hay fever problems will often report anecdotally that they are taking CLA and feel better.”
If CLA has the power to bolster our immune systems, making us feel better more often, that means it will keep us in the gym longer and more consistently. That could be its true power when it comes to helping us build muscle and burn fat.
Pass the Marsupial
It has long been known that milk and meat are the main dietary sources of CLA. Over the past several years, it has been discovered that pastured animals—cattle and dairy cows that are grass-fed rather than grain-fed—can contain five times more CLA than conventionally raised animals. But even more recently, the single richest source of CLA has been discovered: the kangaroo.
Don’t be surprised. Over two million kangaroos are harvested for their meat every year. (They are far from endangered, as there are 48 different species and more than 35 million kangaroos in Australia.) Most of the meat goes into dog and cat food, but kangaroo steaks began popping up in Australian supermarkets with more frequency a few years ago with the outbreak of mad cow disease. Considering that kangaroo meat is loaded with high-quality protein, CLA, iron and zinc, more of us might consider throwing another ’roo on the Bar-B.
Best Sources of CLA
Since CLA is found primarily in meat and dairy products, the list of foods with a high concentration of CLA is a short-ish one. You can try both Tonalin and Clarinol—CLA supplements that can be found at most health and fitness stores. Vegans are pretty much stuck with mushrooms and sunflower oil—both of which are high in linoleic acid. Human breast milk is also high in CLA, but you’re liable to get arrested if you try to tap that from the source.
If you’re looking for high levels of CLA, you’d better ruminate on ruminants. What are ruminants, you ask? They’re animals, like cows, that have more than one stomach. Digestion in these animals begins in an organ called the rumen, where CLA is formed. The animal regurgitates and rechews its cud before eventually digesting the CLAs, where they enter the meat and milk. Here are some common ruminant food sources, along with their CLA values (milligrams of CLA per gram of fat).
Commercially produced beef: 4.3 mg
Grass-fed beef: 21.5 mg
Swiss cheese: 6.7 mg
Turkey: 2.5 mg
Lamb: 5.6 mg
Low-fat yogurt: 4.7 mg
Vegetable oil: 1 mg