AHDB lead nutritionist questions Harvard study diabetes claims

A new study from Harvard School of Public Health has been widely reported in the media over the last week. Its headline-grabbing claim is that people who eat two servings of red meat a week are at increased risk of developing type-2 diabetes. However, delve a little deeper into the methodology of the study and the picture becomes much less categorical.

Kate Arthur, Lead Nutritionist at the Defra-sponsored Agriculture and Horticulture Development Board (AHDB) did just that and discovered some shortcomings in the study that bear closer scrutiny including the observational nature of the research and the potential for selection bias.

Kate Arthur says "The figures quoted in the media suggest that if you eat red meat every day, your chances of getting type 2 diabetes go up by 62%. However, this figure does not account for bodyweight, and the study did report that if when you adjusted for BMI (body mass index) the risk was 12%, therefore significantly lower to what has been reported in the press release and subsequent media".

Award-winning dietitian and health writer Dr Carrie Ruxton also weighed in on the debate saying: "“This latest US study is observational, which means it isn’t designed to test cause and effect. We know from intervention trials that diets with lean red meat have a neutral effect of blood sugar and insulin levels. This conflicts with observational studies suggesting a link with diabetes. We also know that Americans diets vary from those in the UK, which could impact the results of this study."

AHDB caution that "Rather than making drastic dietary changes based on a single study, it's wiser to consider the entirety of the evidence, especially from systematic reviews and meta-analyses (global health-based research), which are considered the gold standard in research methods. When evaluating studies about meat and health, it's essential to be circumspect and account for other potential factors at play."