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Colorectal cancer risk link to ‘inflammatory’ foods

Inflammation-causing diets associated with higher risk of colorectal cancer in men and women

Louise Prime

Friday, 19 January 2018

Men and women whose diets have a higher proportion of inflammation-causing foods are more likely to develop colorectal cancer than those not eating inflammation-causing diets, according to US researchers. They say the findings from their study*, published in JAMA Oncology, suggest inflammation as a potential mechanism linking dietary patterns and colorectal cancer development.

The research team, led from Harvard T.H. Chan School of Public Health in Boston, said it already thought that inflammation has a role in the development of cancer – and they added that what people eat can influence inflammation in the body, as measured by inflammatory biomarkers. They were interested in whether or not diet might be a modifiable risk factor in the prevention of colorectal cancer, and designed a study to elucidate the role of dietary inflammatory potential in colorectal cancer development.

They analysed data covering a cohort of 121,050 male and female health professionals enrolled in long-term studies – 46,804 men (Health Professionals Follow-up Study: 1986-2012) and 74,246 women (Nurses’ Health Study: 1984-2012). Participants had completed questionnaires every four years, including questions about their diet. The research team assigned scores to participants’ diet, calculated from their responses to the food questionnaires, based on 18 food groups characterised for their inflammatory potential. They then investigated the associations between these scores and risk of incident colorectal cancer, during a 26 years’ follow up.

They reported that higher scores, reflecting a diet high in foods with the potential to cause inflammation – including meats, refined grains and high-calorie beverages – were associated with increased risk of developing colorectal cancer for both men and women. Overall, people with scores in the highest quintile had a 32% greater risk of colorectal cancer than those in the lowest quintile; but the figures were 44% for men, and 22% for women.

The strength of the association also varied with other factors. In men who consumed no alcohol, those with scores in the highest quintile had a 62% higher cancer risk compared with those in the lowest quintile; for women the figure was 33%, although this was not statistically significant. Body weight also had an impact. For obese/overweight men, those with scores in the highest quintile had a 48% higher risk than those in the lowest quintile; and for lean women the figure was 31%, although this did not quite reach significance.

The researchers acknowledged that interpretation of their results is limited by their study’s reliance on self-reporting of diet and lifestyle factors. But they concluded: “[Our] findings suggest that inflammation is a potential mechanism linking dietary patterns and colorectal cancer development. Interventions to reduce the adverse role of proinflammatory diets may be more effective among overweight/obese men and lean women or men and women who do not consume alcohol.”

*Tabung FK, Liu L, Wang W, et al. Association of dietary inflammatory potential with colorectal cancer risk in men and women. JAMA Oncology. Published online January 18, 2018. doi:10.1001/jamaoncol.2017.4844.

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