The study, an intense literature review of previous studies - a study of studies - was conducted by the World Cancer Research Fund (WCRF) and American Institute of Cancer Research (AICR) and recommended that the consumption of red meat (beef, pork, lamb) and processed meats should be limited to 18 ounces (500 grams) per week due to the cancer link.

In response, the National Cattlemen's Beef Association (NCBA) commissioned Exponent Health Sciences to conduct its own review, which found "no conclusive evidence" of such a link.

However, USDA's Center of Nutritional Policy & Promotion, which houses the advisory committee that will write USDA's 2010 Dietary Guidelines, indicated in April that it would defer to WCRF/AICR's work on a number of diet and cancer questions, NCBA executive director for human nutrition research Shalene McNeill told Feedstuffs.

Accordingly, NCBA commissioned Exponent to conduct a review of WCRF/AICR's study, specifically as it pertained to colorectal cancer, she said.

The review was led by Exponent senior managing scientist Dr Dominik D. Alexander.

Dr Alexander, in a letter to the co-executive secretary of USDA's advisory committee, noted that the "totality" of available epidemiological evidence does not support "a causal association" between consumption of red meat and cancer, including colorectal cancer.

He said findings from cohort studies, i.e., other studies like WCRF/AICR's, have shown "weak" associations that are not statistically significant, that vary by anatomic sites within the colorectum and by gender and that are subject to diverse definitions of categories of meat and measures of intake.

McNeill said Alexander and NCBA met with WCRF/AICR not in a confrontational way but to determine if the two groups would acknowledge their report's errors, and they (1) did so, (2) said they would address the errors in continuous updates and (3) said they would write to the USDA advisory committee to inform it of the errors and omissions.