Benefits of fish oils may be reduced in obese patients due to high inflammation levels.
Patients with cardiovascular disease have long been advised to take daily fish oils to help lower blood pressure, reduce triglycerides, and improve overall heart health. Those who take fish oils may also benefit from a reduced risk of colon cancer, a new study suggests.
Personalized doses of omega-3 fatty acids were found to reduce levels of prostaglandin E2 (PGE2) in the colon, which is a compound known to cause colon cancer, according to a study published by Cancer Prevention Research. However, these benefits were reduced among overweight patients.
PGE2 is derived from omega-6 fatty acids and is used by the body to control inflammation and promote healing. Typically, PGE2 protects against injury and infections in the colon, but when it is out of balance, it has been linked to inflammation and other diseases, such as cancer and heart disease, according to the authors.
Omega-3 fatty acid is known to lower the amount of omega-6 available, which is key to controlling PGE2 production.
A significant portion of Americans are overweight or obese, which causes inflammation. Long-term inflammation can result in prolonged overproduction of PGE2 and colon cancer. The authors said the inflammation can also increase the risk of type 2 diabetes and heart disease.
"Our blood test of ratios of omega-3 and omega-6 fatty acids was one way to personalize fatty acid dosing, but it wasn’t enough in the case of overweight or obesity," said researcher Zora Djuric, PhD. "The metabolic effects of having excess weight may reduce preventive strategies and increase the risk of colon cancers."
Included in the study were 48 patients of varying weights who had no previous history of cancer. Patients were administered a customized dose of omega-3 fatty acids for 3 months and underwent blood tests and colon biopsies.
In normal-weight patients, a fish oil supplement was observed to reduce PGE2 by 50%, as indicated by blood tests, according to the study.
Even when overweight or obese patients received larger doses of omega-3s, protection against colon cancer was still diminished. The findings indicate that these individuals may be at a higher risk of colon cancer.
The authors noted that balanced PGE2 is important in the colon since the bacteria are neighbors to the colon wall. PGE2 and PGE3 are crucial for maintaining defense against infection, but the inflammatory response must dampen and not stay elevated, the study noted.
Additionally, the success of the fish oil supplements in normal-weight patients raises more questions, such as how the reduction affects PGE2 balance, according to the study.
"We know that if people take nonsteroidal anti-inflammatory drugs [NSAIDs], such as aspirin or ibuprofen, then their PGE2 goes down by about half and their risk of colon cancer is reduced," Dr Djuric said. "The problem with taking NSAIDs is that over a long time, they can cause ulcers. So we wanted to use a natural product such as the omega-3 fatty acids in fish oil to reduce PGE2 by a similar amount that is achieved with NSAIDs."
Future studies should investigate multiple eicosanoids to determine the best protective balance of PGE2, as well as including obese animal models to better represent the general population, according to the authors.
"We need methods for dosing preventive agents against colon cancer that are effective for people who have a higher body weight,” Dr Djuric said.