Get a barrel of benefits from one little fatty acid
Conjugated linoleic acid sounds too good to be true
It helps your patients lose body fat while building lean muscle mass, dramatically reduces the risk of breast cancer, brings rampant blood sugars under control, cuts triglyceride levels in half, stops asthma attacks cold in their tracks, and clears out clogged arteries. It’s one little fatty acid.
There is a growing body of hard evidence being compiled by strong and reputable research facilities showing that conjugated linoleic acid (CLA) does all this and more.
CLA occurs naturally in dairy products and beef, but Americans are getting much less CLA in our diets than we did 30 years ago, says cancer and asthma researcher Delbert Dorscheid, MD, PhD, professor of pulmonary and critical care medicine at the University of Chicago.
This is because of two factors, says Dorscheid. First, Americans have dramatically reduced their consumption of beef and dairy products to avoid cholesterol. Second, cattle production of CLA has been reduced by 65% because of newer farming methods by which cattle are fed forage pellets instead of being allowed to feed on pasture grass, which their digestive systems converts into CLA.
CLA: Complex, yet simple
The mechanism behind the plethora of benefits of CLA is complex, yet elegantly simple, says Dorscheid. "The free fatty acid is absorbed from the gut and delivered to all cells in the body. It’s a building block for lipid membranes and so it gets incorporated into every cell in the body."
In this way, conjugated linoleic acid is at the starting point for every signaling mechanism in the body, he explains. An example of the action can be seen in a fat cell, he says. "You eat, so there is an insulin release. The insulin finds the insulin receptors of the fat cell and initiates the signal to the fat cell to store fat. CLA is the basic ingredient that assures the proper communication. It’s the same for all cells."
CLA works very well in chronic disease situations, according to Dorscheid, because it modulates the signaling mechanisms in all cells to help them function properly.
More than 200 studies published worldwide provide evidence that CLA has multiple health benefits. Among the findings:
- Weight loss.
Three significant clinical trials show that dosages of 3.4 grams and 6.8 grams of CLA a day resulted in weight loss of 6-8 pounds in 12 weeks. Those at the higher intake levels also increased lean body mass. Animal studies show obese animals with 16% body fat reduced their body fat to 3% to 4% when they were fed CLA.1
"It appears to inhibit lipoprotein lipase uptake of fat over a period of time," says nutrition scientist and food microbiologist Mark Cook, PhD, professor of animal science and toxicology at the University of Wisconsin in Madison.
"It’s very interesting because we know the weight loss is not caused by a simple fluid reduction in the body, says Cook. "In fact, animals taking CLA increase their water consumption as much as 70% while increasing lean muscle tissue."
In addition, researchers believe the reduction in dietary CLA is a contributing factor to the steady rise in obesity and related chronic diseases in the United States, says Dorscheid.
Cook and Dorscheid warn that there are some sham products on the market that contain only corn oil, but products containing Tonalin contain effective and standardized doses of CLA.
- Cancer protection.
"CLA is a very potent inhibitor of prosta-glandin synthesis," says Cook. "There is a theory that all humans get cancer all the time, but the body’s immune system responds to it properly, so the malignancy never begins to grow. Since cancer cells make prostaglandins to avoid immune system detection, inhibiting the manufacture of prostaglandins means the immune system can see’ the malignant cells before they get out of control."
In animal studies, French researchers found that animals with the highest CLA levels had a 70% reduced incidence of breast cancer.2
Additional research shows that CLA intake at 1% of dietary calories during mammary gland maturation reduces the risk of breast cancer development when exposed to cancer-causing agents. And in a model of breast cancer metastasis, CLA levels at 0.1% to 1% were as effective as indomethacin in reducing tumor spread.3
Dorscheid says the average daily intake of CLA in the United States is between 15 mg and 175 mg, far below the 3,000 mg level at which anticarcinogenic effects have been seen.
- Lowering blood sugars.
Purdue University studies show that human subjects with Type 2 diabetes given CLA were able to reduce their HbA1c levels from 11.5 to 10.1 in 12 weeks with no other interventions.
In addition, the Purdue research team in West Lafayette, IN, that included associate professor of nutrition Martha Belury, PhD, RD, found that patients cut their triglyceride levels in half and shed 6-8 pounds while on a restricted calorie diet.4
In an animal study, Belury found that CLA had an identical effect to troglitazone in getting sugars under control after a glucose challenge. "I think it is likely that losing the abdominal weight could be one of the mechanisms at work in getting the blood sugars under control," says Belury.
"We also think the importance of this could be even more significant when we look at people who have impaired glucose tolerance," she adds.
- Protectant against heart disease.
CLA’s antithrombotic action is attributed to reducing blood plasma levels of LDL cholesterol and tricyglycerols, plus recent work has shown antiplatelet action that inhibits thromboxanes, which are among the fatty acid signals CLA can modulate.
Four human trials involved the measurement of blood lipid levels, but none were conclusive in identifying clinically important changes.5
However, Dorscheid says none of the human studies were long enough to assess for long-term benefits. "Given the promising effects as noted in extended animal models, extended human trials are needed," he says.
- Asthma relief.
Although there have been no formal human studies on the effects of CLA on asthma, animal studies show dramatic reductions in the inflammatory process with the use of CLA. Dorscheid says prostaglandin inhibition is the likely mechanism at work in asthma as well as in cancer prevention and mediation.
Research on CLA is relatively new, says Cook, who says he thinks he has been taking CLA "longer than any human being on the planet, 3 g a day since 1994, and I’m in excellent health. It even cleared up psoriasis that has been unresponsive to any medication for years."
Since CLA is a naturally occurring substance in the tissues and body fluids in humans, Dorscheid said it should be regarded as nontoxic. However, gastrointestinal disturbances have been detected in some clinical trials, and two studies indicate CLA may lead to lipid accumulation and enlargement of the liver in CLA-fed mice, while other studies report no clinically important changes in blood levels of liver enzymes during treatment with CLA. "These studies show there is a need for more study," says Dorscheid. "But the results we have seen so far, with hundreds of studies, look exceedingly hopeful."
References
1. Vessby B. Conjugated linoleic acid (CAL) reduces body fat content in humans. Chem Phys Lipids 1999; 101:AT2/01.
2. Vissoneau S. Conjugated linoleic acid suppresses the growth of human breast adenocarcinoma cells in SCID mice. Anticancer Res 1997; 17:969-973.
3. Thompson H. Morphological and biochemical status of the mammary gland as influenced by conjugated linoleic acid: Implication for reduction in mammary cancer risk. Cancer Res 1997; 57(22):5,067-5,072.
4. Houseknect K, Belury MI. Dietary conjugated linoleic acid normalizes impaired glucose tolerance in the Zucker diabetic fa/fa rat. Biochem Biophys Res Commun 1998; 244(3):678-682; 629 and 247(3):911.
5. Lee Kl. Conjugated linoleic acid and atherosclerosis in rabbits. Atherosclerosis 1994; 108(1):19-25.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content