A Wrench In The Dietary Guidelines

Dietary recommendations continue to be one of the most confusing topics in modern medicine simply because of the paucity of good data and the complexity of randomization within these studies.  It seems like every day something new comes out challenging the peaceful paradigm of what seems intuitive.  The most widely accepted dietary regimen for the last 40 years is the Mediterranean Diet which advocated largely plant-based foods, unsaturated fats such as olive oil, and copious fruits and vegetables.  As part of this, it is postulated that red meats should be limited to only a few meals per month; many prominent Cardiologists support this recommendation as part of the plant based diet, which has gained tremendous popularity.

An article published by Dr Daniel Dressler et al in the Annals of Internal Medicine October 2019, however, raises eyebrows to the data behind these recommendations.  Because of the significance of this, this article was even highlighted as one 12 significant “guideline changing” articles within NEJM Guideline Watch 2020.

As part of the study, an independent research panel scoured literature underpinning associations between red meat consumption and multiple disease markers, and highlighted multiple concerning limitations:  Most studies were observational studies with high risk of bias, poor statistical methodology, and inordinate amounts of cultural and population bias.  Meta-analysis of 12 randomized controlled trials with over 10 year follow-up on all cause mortality (including cancer markers, heart disease, development of diabetes etc.) showed no statistical significance between patients who consumed high or low quantities of red meat.   This difference was defined by greater than 3 servings reduction in red meat per week; does this mean that patient’s with even tighter reduction in red meats would yield the same result?  What about outcomes from those consuming extremely high quantities in red meat?  We don’t know!  This article supports the ambiguity here, and highlights the need to perform more research prior to defining causation. 

Nothing in the article argues harm from reducing red meat consumption, and personally I would recommend to continue to do so, but it highlights the need to question dietary regimens that seem too black and white amidst this enormously challenging and controversial field.

Dressler, Daniel MD et al.  Guideline for Consumption of Unprocessed Red Meat and Processed Meat.  Annals of Internal Medicine, Oct 1 2019.

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