Researchers have found the fatty acids in red meat and dairy products could improve immune response against cancer.

According to a study published in Nature, people with higher levels of trans-vaccenic acid, a long-chain fatty acid in the blood, responded better to immunotherapy. TVA is typically found in beef, lamb and dairy products.

The findings suggest the possibility of using this fatty acid as a nutritional supplement to complement treatments for cancer.

"There are many studies trying to decipher the link between diet and human health, and it's very difficult to understand the underlying mechanisms because of the wide variety of foods people eat. But if we focus on just the nutrients and metabolites derived from food, we begin to see how they influence physiology and pathology," said Jing Chen, a senior author of the study.

Researchers tried to determine how nutrients and other molecules circulating in the blood affect cancer development and cancer treatments.

For this, they evaluated a database of around 700 known metabolites (intermediate products of metabolism that came from food) and screened them for their anti-cancer properties. After shortlisting the top six candidates in both human and mouse cells, the team found that TVA had the best anti-tumor immunity.

"By focusing on nutrients that can activate T cell responses, we found one that actually enhances anti-tumor immunity by activating an important immune pathway," Chen said.

A follow-up study showed that mice fed on a diet enriched with TVA had reduced the tumor growth potential of melanoma and colon cancer cells and enhanced the ability to infiltrate tumors compared to the control group.

The researchers conducted a series of molecular and genetic analyses that showed TVA could be used to promote T-cell activity, responsible for the immune response against the diseases.

However, consuming too much red meat and dairy could pose negative health effects. Hence, researchers caution the findings should not be taken as an excuse to eat more meat. They also suggest the possibility of finding similar beneficial fatty acids in plant-based food.

"There is early data showing that other fatty acids from plants signal through a similar receptor, so we believe there is a high possibility that nutrients from plants can do the same thing by activating the CREB pathway as well," Chen said.