Reformed diet may slow prostate cancer cell growth

Men with prostate cancer may be able to manage the disease simply by watching their diet, according to a study conducted by researchers at UCLA’s Jonsson Comprehensive Cancer Center.

The study showed that men who followed a low-fat, high omega-3 diet for four to six weeks before prostate removal experienced a lower rate of cancer cell growth than men who followed a traditional “Western” diet, which had almost three times the amount of fat calories than the low-fat diet in the study.

Participants on the modified diet had higher concentrations of omega-3 oils in their cancer cells than those of men on the high-fat, low omega-3 diet. This indicated to researchers that a change in diet could affect both the composition and rate of growth of cancer cells.

Dr. William Aronson, first author and principal investigator of the study, said he believes the dietary implications of the study are significant because the changes in diet manifested in the cancer cells’ composition.

Aronson said large-scale studies on cancer and nutrition are rare because of their high-implementation costs, which arise because researchers need to ensure uniformity in patients’ diets.

For this trial, all food was prepared by the UCLA Clinical and Translational Science Institute and was delivered directly to patients by the university, said Colette Galet, a researcher with the UCLA Department of Medicine who co-authored the study. Patients were also required to meet with a dietitian and keep food diaries.

The researchers’ primary goal was to test the effect of the modified diet on IGF-1, a component of blood that can be used to measure the effectiveness of a prostate cancer treatment.

Despite effects on prostate cancer cell proliferation and makeup, researchers found no significant link between the modified diet and IGF-1 levels.

“If they had a more drastic diet with more pronounced weight loss and much fewer calories overall, I think you would have seen a more dramatic effect on the cancer and lower IGF-1,” said Dr. Pinchas Cohen, an author on the study.

Aronson said the men enrolled in the study had early-stage prostate cancer, and researchers examined the prostate cells after they had been surgically removed.

However, researchers believe there are also potential benefits from the diet for patients with advanced-stage prostate cancer that has spread beyond the prostate.

But men with prostate cancer should not yet make dietary changes given the small-scale nature of the study, Aronson said. He is currently organizing a larger, yearlong study of 100 men to test the study’s findings.

The participants in the next study have chosen to forgo medical therapy and will be closely monitored by clinicians to track their disease, a technique called active surveillance.

“If the findings are confirmed in the next clinical study, to me that would be very good news for prostate cancer patients because there may be a lifestyle change that they could make that would potentially slow the growth and progression of prostate cancer,” Aronson said.

Future studies may examine the combined effects of patients’ diets and typical medical treatments for cancer. Such treatment combinations have shown benefits in other forms of cancer, such as lung cancer.

“Now we’re interested in combining nutrition therapy with types of targeted therapies, such as radiation and chemotherapy,” Aronson said.

He also said researchers believe a diet low in saturated fat and high in omega-3 oils may increase the effectiveness of standard cancer treatments and reduce their side effects. Aronson said such studies are already being conducted on animals and have shown effectiveness in other types of cancers. He also added that future tests will determine their effectiveness in humans and potentially lead to their use in the clinical treatment of cancer.