“In our study, there was insufficient evidence for any differences between the dietary pattern groups and risk of CRC, though confidence intervals were wide,” Diego Rada-Fernandez de Jauregui, MD, and colleagues wrote in the International Journal of Cancer. “These results indicate that protective associations of red meat free diets on colorectal cancers merit further investigation in a larger study with larger numbers of cases.” Dr. Jauregui is from the Nutritional Epidemiology Group at Leeds, UK, and the University of the Basque Country, Spain.
According to the study, the International Agency for Research on Cancer currently classifies red meat as “probably carcinogenic to humans” based mostly on a link to increased risk for CRC. However, there is limited evidence linking dietary patterns with increased CRC risk.
According to de Jauregui and colleagues, “nutrients and foods are consumed in combination, so effects on disease risk benefit” must be considered looking at the entire eating pattern. To do that, they used data from 32,147 women participating in the United Kingdom Women’s Cohort Study (UKWCS). Participants completed a 217-item good frequency questionnaire, and their dietary patterns were split into four groups based on consumption of red meat, poultry, and fish, as well as vegetarian dietary patterns.
Of the included women, 65% were eaters of red meat, 3% were poultry eaters, 13% ate fish, and 19% were vegetarians. During the study’s 17-year follow-up, 462 cases of CRC were documented, including 335 colon cancers and 152 rectal cancers.
Red meat–free diets had no significant risk reduction for overall colorectal cancer risk, colon cancer risk, or rectal cancer risk. However, in evaluating colon cancer subsites, the researchers found a significant reduction in the risk of distal colon cancer in red meat–free diets, compared with red meat diets in an age-adjusted model (HR, 0.58; 95% CI, 0.36–0.92) and a fully adjusted model (HR, 0.56; 95% CI, 0.34–0.95).
According to the researchers, the women in this study ate a “relatively low” amount of red meat, with a mean of 51.6 grams consumed per day. Therefore, the relationship between red meat consumption and risk for distal colon cancer is of interest “from a public health point of view, as in this cohort, a red meat eating pattern characterized by lower overall meat intakes, may be generally [associated with] lower risk of colorectal cancers compared to populations with a higher meat consumption; for example, women aged 35–59 years in the National Diet and Nutrition Survey are consuming on average 131 g meat/day.”