A glass a day keeps cancer at bay
a study by Dale Bauman and William Kelly of the Cornell University in Ithaca, us, shows that supplementing a cow's diet with corn oil increases the amount of conjugated linoleic acid (cla), a fatty acid manufactured by bacteria in the cow's rumen, which helps in preventing melanoma and leukaemia. cla is found in dairy products and meat of animals that ferment food in their guts (New Scientist, Vol 152, No 2056).
cla is thought to work by oxidising chemicals that can induce cancer causing mutations in cells. According to Bauman, "There has not been any epidemiological studies on cla in humans.' But a recent Finnish study examined the link between consumption of dairy products and the risk of breast cancer. "It concluded that there was a protective effect associated with drinking milk,' says Bauman.
Experiments conducted on rats suggest that a person weighing 70 kg would need to consume 3.5 gm of cla every day for an appreciable benefit. A normal daily American diet contains about one gram cla. Doubling the amount of unsaturated fat in a cow's diet increased the proportion of cla in milk from two milligrams per gram of fat to 4.5 milligrams per gram.
cla is found only in fat. "This means that people drinking skimmed milk get no cla,' says Mark McGuire of the University of Idaho, us. He says that people who drink semi-skimmed milk, having two per cent fat, consume only 60 per cent as much cla as those drinking whole milk.