It's still an open question, but there is no question that ALA represents a dietary difference between the sexes. For women, it's a healthful fat. For men with heart disease or major cardiac risk factors, it may also be a good choice — but men with more reason to worry about prostate cancer should probably get their omega-3s from fish and their vegetable fats largely from olive oil.
Although canola oil appears to be good for the cardiovascular system, two Harvard studies have raised concerns that ALA might be bad for the prostate. In 1993, the Health Professionals Follow-up Study of 47,781 men published a major evaluation of dietary fat and prostate cancer. It found that saturated fat from animal sources such as red meat and whole-fat dairy products was linked to a 2.6-fold increase in prostate cancer. But the study also provided some disquieting news about ALA: Men who consumed the most ALA were 3.4 times more likely to be diagnosed with prostate cancer than those who had the lowest dietary intake.
Some fat is an important part of your diet; fat is part of every cell. It maintains skin and hair; stores and transports fat-soluble vitamins A, D, E and K; keeps you warm; and protects your internal organs. It even helps your mental processes—not surprising given that fat comprises about 60 percent of your brain. But many women consume too much fat. The American Heart Association (AHA) recommends that you keep your total fat intake between 25 and 35 percent of your total calories.