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Hiding unhealthy heart outcomes in a low-fat diet trial: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial finds that postmenopausal women with established coronary heart disease were at increased risk of an adverse outcome if they consumed a low-fat ‘heart-healthy’ diet
  1. Timothy David Noakes
  1. Applied Design, Cape Peninsula University of Technology, Bellville, South Africa
  1. Correspondence to Professor Timothy David Noakes; timothy.noakes{at}uct.ac.za

Abstract

The Women’s Health Initiative Randomized Controlled Dietary Modification Trial (WHIRCDMT) was designed to test whether the US Department of Agriculture’s 1977 Dietary Guidelines for Americans protects against coronary heart disease (CHD) and other chronic diseases. The only significant finding in the original 2006 WHIRCDMT publication was that postmenopausal women with CHD randomised to a low-fat ‘heart-healthy’ diet in 1993 were at 26% greater risk of developing additional CHD events compared with women with CHD eating the control diet. A 2017 WHIRCDMT publication includes data for an additional 5 years of follow-up. It finds that CHD risk in this subgroup of postmenopausal women had increased further to 47%–61%. The authors present three post-hoc rationalisations to explain why this finding is ‘inadmissible’: (1) only women in this subgroup were less likely to adhere to the prescribed dietary intervention; (2) their failure to follow the intervention diet increased their CHD risk; and (3) only these women were more likely to not have received cholesterol-lowering drugs. These rationalisations appear spurious. Rather these findings are better explained as a direct consequence of postmenopausal women with features of insulin resistance (IR) eating a low-fat high-carbohydrate diet for 13 years. All the worst clinical features of IR, including type 2 diabetes mellitus (T2DM) in some, can be ‘reversed’ by the prescription of a high-fat low-carbohydrate diet. The Women’s Health Study has recently reported that T2DM (10.71-fold increased risk) and other markers of IR including metabolic syndrome (6.09-fold increased risk) were the most powerful predictors of future CHD development in women; blood low-density lipoprotein-cholesterol concentration was a poor predictor (1.38-fold increased risk). These studies challenge the prescription of the low-fat high-carbohydrate heart-healthy diet, at least in postmenopausal women with IR, especially T2DM. According to the medical principle of ‘first do no harm’, this practice is now shown to be not evidence-based, making it scientifically unjustifiable, perhaps unethical.

  • coronary artery disease
  • epidemiology
  • risk factors
  • diabetes mellitus

Data availability statement

The publication makes use of data already published in the scientific literature.

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Data availability statement

The publication makes use of data already published in the scientific literature.

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Footnotes

  • Twitter @ProfTimNoakes

  • Contributors TDN wrote the manuscript without assistance from anyone else.

  • Funding The Cape Peninsula University of Technology contributes to the costs of the submission and publication of this article. TDN covered all other expenses.

  • Competing interests TDN is the author of a number of books on low-carbohydrate diet, including The Real Meal Revolution, Super Food for Superchildren, Lore of Nutrition, The Banting Pocket Guide, Real Food on Trial and The Eat Right Revolution. TDN derives no personal income from the sale of these books. Instead all royalties are donated to the NGO The Noakes Foundation, of which TDN is the chairman. The money is used to fund the work of The Noakes Foundation, including the Eat Better South Africa Campaign.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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