Lipid Nutrition is announcing the findings of a new human trial using CLA, that reinforces the fatty acid's fat mass reduction claim and shed light on the main locations of the fat reduction on the human body. The results, presented by Dr Sandra Einerhand, director nutrition and toxicology Europe, at Vitafoods in Geneva, reinforce the ingredient's promotional claim to be a body shaper – especially for the upper leg and abdomen areas.
CLA (conjugated linolenic acid) is a fatty acid naturally present in meat and dairy products. Due to changes in the Western diet, average intake of CLA has fallen; if the fat is removed from a dairy product to make a low fat version that will be acceptable to consumers, CLA is removed along with it. Moreover Dr Einerhand explained that CLA is metabolized by bacteria in the stomachs of cows from the grass they eat, but modern farming methods use corn as feed, rather than grass.
This has led nutraceutical companies to research and promote CLA for use in dietary supplement and food products, largely based on its two-fold effect on humans: the reduction of fat mass and the induction of lean body mass.
The mechanism of action has been well studied: if fat consumed is not used for energy, the triglycerides are taken up by fat cells – a mechanism for which the enzyme lipoprotein lipase is responsible. CLA inhibits this enzyme, and instead the triglycerides are diverted to the muscle cells to be burnt. Here the CLA induces the activity of another enzyme, carnitine palmitoyl transferase, which is responsible for oxidation and the burning of fat.
The new placebo-controlled, randomized, double-blind study was conducted at an independent research institute and involved 180 obese or overweight adults with a body mass index between 28 and 32. Over a six month period study subjects received either 3.4g of CLA each day, or a placebo (olive oil).
Dr Einerhand said that the results were already evident eight to 12 weeks into the study, but at the end of the six months the effect on fat mass was seen to be a decrease of around 4.4 pounds (2kg) compared to placebo. Lean body mass was seen to increase by an average of 1 pound (0.4kg) in the CLA group, over the placebo group.
But the area in which the study really shed light is the location of fat mass reduction – seen to be focused on the abdomen and the legs. This gives credence to the ingredient's promotional claims to be a body shaper.
In addition, the study provided more evidence for the safety of CLA over a long period: it was well-tolerated by all the participants over the six-month period.
The researchers also measured certain safety parameters, such as inflammatory and diabetagenic markers. In a sub group of 41 participants, the researchers measured insulin sensitivity – an important consideration since overweight or obese people may run a higher risk of metabolic syndrome or full-blown type-II diabetes. To do this, they used an englycemic clamp – a time consuming procedure that is nonetheless considered the gold standard. “We needed to be sure that it does not affect insulin sensitivity,” said Dr Einerhand.
Long-term supplementation with conjugated linoleic acid (CLA) reduces body fat mass (BFM) and increases or maintains lean body mass (LBM). However, the regional effect of CLA was not studied. The study aimed to evaluate the effect of CLA per region and safety in healthy, overweight and obese adults.
A total of 118 subjects (BMI: 28-32 kg/m2) were included in a double blind, placebo-controlled trial. Subjects were randomised into two groups supplemented with either 3 x 4 g/d CLA or placebo for 6 months. CLA significantly decreased BFM at month 3 (Delta=- 0 x 9 %, P=0 x 016) and at month 6 (Delta=- 3 x 4 %, P=0 x 043) compared with placebo. The reduction in fat mass was located mostly in the legs (Delta=- 0 x 8 kg, P<0 x 001), and in women (Delta=-1 x 3 kg, P=0 x 046) with BMI >30 kg/m2 (Delta=-1 x 9 kg, P=0 x 011), compared with placebo. The waist-hip ratio decreased significantly (P=0 x 043) compared with placebo. LBM increased (Delta=+0 x 5 kg, P=0 x 049) within the CLA group. Bone mineral content was not affected (P=0 x 70). All changes were independent of diet and physical exercise. Safety parameters including blood lipids, inflammatory and diabetogenic markers remained within the normal range. Adverse events did not differ between the groups.
It is concluded that supplementation with CLA in healthy, overweight and obese adults decreases BFM in specific regions and is well tolerated.
Lipid Nutrition, press release; Mar 2007
Gaullier JM, Halse J, Hoivik HO, Hoye K, Syvertsen C, Nurminiemi M, Hassfeld C, Einerhand A, O'Shea M, Gudmundsen O. Six months supplementation with conjugated linoleic acid induces regional-specific fat mass decreases in overweight and obese. Br J Nutr. 2007 Mar;97(3):550-60.