New York, Nov 23 (IANS): Turns out eating beef and dairy may bolster your body's immune response against cancer, according to a study.

Trans-vaccenic acid (TVA), a long-chain fatty acid found in meat and dairy products from grazing animals such as cows and sheep, improves the ability of CD8+ T cells to infiltrate tumours and kill cancer cells, revealed the study by researchers from the University of Chicago.

The study, published in the journal Nature, also shows that patients with higher levels of TVA circulating in the blood responded better to immunotherapy, suggesting that it could have potential as a nutritional supplement to complement clinical 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, Professor of Medicine at University of Chicago in the US.

"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 added.

However, Chen cautioned that there is a growing body of evidence about the detrimental health effects of consuming too much red meat and dairy, so this study shouldn't be taken as an excuse to eat more cheeseburgers and pizza.

For the new study, the team started with a database of around 700 known metabolites that come from food and assembled a "blood nutrient" compound library consisting of 235 bioactive molecules derived from nutrients.

They screened the compounds in this new library for their ability to influence anti-tumour immunity by activating CD8+ T cells, a group of immune cells critical for killing cancerous or virally-infected cells.

After the scientists evaluated the top six candidates in both human and mouse cells, they saw that TVA performed the best. TVA is the most abundant trans fatty acid present in human milk, but the body cannot produce it on its own.

Only about 20 per cent of TVA is broken down into other byproducts, leaving 80 per cent circulating in the blood. "That means there must be something else it does, so we started working on it more," Chen said.

He noted that the study also indicates that nutrient supplements such as TVA could be used to promote T cell activity.

"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," Chen said.