Conjugated linoleic acid (CLA) is a form of linoleic acid, an omega-6 essential fatty acid. CLA is found naturally in beef and the milk fat in dairy products, but you're unlikely to consume more than a gram of it a day if you include those foods in your diet. CLA supplements have been widely promoted in recent years as aids to weight loss and have also received attention as means of strengthening the immune system, protecting against certain types of cancer, and preventing cardiovascular disease.