What is the role of meat in a healthy diet?

Abstract

Red meat is a nutrient dense food providing important amounts of protein, essential amino acids, vitamins, and minerals that are the most common nutrient shortages in the world, including vitamin A, iron, and zinc. Despite claims by the World Health Organization (WHO) that eating processed meat causes colon cancer and red meat probably causes cancer, the observational data used to support the claims are weak, confounded by multiple unmeasured factors, and not supported by other types of research needed for such a conclusion. Although intervention studies are designed to test the validity of associations found in observational studies, two interventions of low-fat, low-meat diets in volunteers that failed to find a benefit on cancer were not considered in the WHO decision. It is likely that the association of red-meat consumption with colon cancer is explained either by an inability of epidemiology to detect such a small risk or by combinations of other factors such as greater overweight, less exercise, lower vegetable or dietary fiber intake, and perhaps other habits that differentiate those who eat the most meat from those who eat the least.