Extra niacin could help prevent treatment-related cancers, study finds

People undergoing chemotherapy may be able to reduce the risk of developing treatment-related cancers by taking supplements of the B vitamin niacin, research by a University of Guelph scientist reveals.

In a study published in the journal Mutation Research, James Kirkland, a human biology and nutritional sciences professor, changed the niacin status of rats receiving cancer treatments. He found that DNA damage is more severe in bone marrow with low niacin levels and that development of other cancers is enhanced. “There were 47 per cent more cancer treatment-related alignancies in niacin-deficient rats,” said Kirkland, who has been examining the nutritional effects of niacin for nearly a decade.

In chemotherapy, drugs damage the DNA of cancer cells that are dividing rapidly within the body. But that DNA destruction also applies to the formation of blood cells in the bone marrow, where cells also divide quickly. “That brings on new treatment-related cancers such as leukemia and cancer of the bone marrow,” Kirkland said. In fact, people undergoing chemotherapy are 10 to 100 times more likely to develop such cancers than the general public, and three to 10 times more likely than cancer patients undergoing radiation.

Kirkland's research shows how niacin deficiency plays a role. In the study, niacin-deficient rats were found to have 80 per cent less of the oxidized co-enzyme nicotinamide adenine dinucleotide (NAD+) in their bone marrow and 65 per cent less in their blood. This is a crucial finding because NAD+ is involved in the repair process for DNA. It is used in the synthesis of poly(ADP-ribose) -- a large molecule made at the site of DNA damage that sends signals notifying cells that damage has taken place. “Niacin deficiency influences this repair process by inhibiting the rejoining of broken DNA strands,” Kirkland said.

Meanwhile, NAD+ concentrations were three times higher in the bone marrow of rats that received niacin supplements, according to the study. “We have found that bone marrow is extremely sensitive to changes in dietary niacin levels, and that niacin status causes dramatic differences in bone marrow poly (ADP-ribose) levels,” Kirkland said.

Cancer patients are already more susceptible to niacin deficiency because of side effects such as nausea and vomiting, he said. Additionally, bone marrow is more sensitive to niacin deficiency than are organs such as the lungs and liver. “Pharmacological supplementation of niacin  may represent a rapid and safe way to help protect the bone marrow cells of cancer patients,” he said.

An earlier study conducted by Kirkland, published by the the American Society for Nutritional Sciences in The Journal of Nutrition, also shows that niacin-deficient rats who have undergone chemotherapy have lower long-term survival rates than rats with adequate or supplemented levels of the vitamin. “This could represent many extra years of disease-free life in human populations,” he said.

Contact:
Prof. James Kirkland
Department of Human Biology and Nutritional Sciences
(519) 824-4120, Ext. 56693
[email protected]

For media questions, contact Communications and Public Affairs: Lori Bona Hunt, (519) 824-4120, Ext. 53338, or Rachelle Cooper, (519) 824-4120, Ext. 56982.