Conjugated Linoleic Acid (CLA) is best known in the sports world for its fat burning and muscle building properties. It's also a potent antioxidant which means it may protect against some diseases including cancer.
What is CLA?
CLA contains a mixture of chemically altered forms of linoleic acid, which is part of the omega-6 family. It occurs naturally in grass-eating animals and unlike other trans fatty acids it is thought to promote rather than harm health.
Humans cannot make CLA but we can get what we need by eating dairy and meat products from grass-feed animals and by taking supplements.
Why do I need CLA?
CLA supplements are mostly used to aid weight loss and improve body composition (the ratio of muscle to fat). Biochemical actions of CLA appear to reduce the percentage of body fat while increasing the percentage of body protein (associated with increased muscle mass).
In one study on mice - the animals treated with CLA had 60% less total body fat than their peers. The research on humans is less clear - although some studies have shown that CLA does slightly reduce body fat.
CLA may also lower total cholesterol levels in the body and have an anti-inflammatory effect.
There is also some evidence to suggest CLA has anti-cancer properties - in studies it appears to block both the growth and spread of tumours. This seems to apply to several types of cancers including cancers of the breast, lung, colon and rectum. But so far most studies have been on animals or in the test tube and more research is needed.
Can CLA ever be bad for you?
CLA is thought to be generally safe. A dose of greater than 3gm per day is recommended to alter body composition. Typical doses range from 3-5g daily.
However, large amounts of CLA may cause stomach upset, diarrhoea and nausea.
You should not take CLA supplements if you have diabetes as CLA may make the condition worse.