Low-Fat Diet May Slow Cancer, Study Says

An ultra low-fat diet and other lifestyle changes may help keep early-stage prostate cancer from worsening, researchers found in a small study that tracked men whose tumors weren’t aggressive.

The study, published in the September issue of the Journal of Urology, promises to increase research into whether diet might really help battle cancer.

The study was led by heart-health guru Dr. Dean M. Ornish, and used his strict regimen, where people become vegetarians, limit dietary fat to 10% of total calories, exercise regularly and learn stress-management techniques such as yoga.

Ornish’s studies have shown that the regimen can help reverse heart disease. There is some evidence that diets high in fat increase the risk of prostate cancer and that certain foods -- such as broccoli, or the nutrient lycopene from cooked tomato products -- are protective.

Ornish and fellow researchers at UC San Francisco recruited 93 men who had decided against treatment for early-stage prostate cancer, a route known as “watchful waiting.”

Half were randomly assigned to the Ornish regimen; the others weren’t asked to vary their routines. The researchers sent participants’ blood samples to Memorial Sloan-Kettering Cancer Center in New York to measure prostate specific antigen, or PSA, a marker used to track prostate cancer growth.

After one year, PSA levels had decreased 4% in the diet group -- unusual for untreated patients -- while the levels rose by 6% in the control group. That difference wasn’t big, but it is statistically significant, and the researchers plan to continue tracking the men to see if it really signals better health.

Also, six of the non-dieters had undergone cancer treatment in that year after all because their disease was progressing. None of the dieters was treated.

Other cellular tests suggested that the diet wasn’t just affecting PSA production, Ornish said. “I always find it amusing” that people call the diet hard, he said. “Compared to having your prostate removed? The only side effects are you feel better and it helps prevent heart disease.”