Emeritus Professor Tim Noakes, in a study published in the journal Open Heart, has criticised the authors of one of the most influential studies relating to diet and health, the Women’s Health Initiative Randomized Controlled Diet Modification Study, for hiding negative findings, as well as reaching “scientifically unjustifiable” and “perhaps unethical” conclusions, writes MedicalBrief.
Noakes, formerly a sports health scientist at the University of Cape Town, said that as long ago as 2012, he had pointed out to the lead author of the WHIRCDMT study that there were negative findings in the study that were being hidden from the profession. “A paper detailing those criticisms was subsequently peer reviewed and published in the SA Medical Journal. I have recently published in Open Heart a follow-up analysis of the more recent publications from the Women’s Health Initiative [and] I draw the conclusion that that $700 million proves that it is now unethical for medical practitioners to prescribe low-fat diets for persons with established coronary heart disease or at risk for CHD [coronary heart disease] because they are insulin resistance.”
Beginning in 1993, the iconic WHIRCDMT study was designed to provide supporting evidence for a single dietary pattern, consistent with the US Department of Agriculture’s 1977 Dietary Guidelines for Americans (DGA), which encouraged North Americans to reduce their dietary, especially saturated, fat intake. In his Open Heart study, Noakes concludes that the prescription of the low-fat “heart-healthy” diet to post-menopausal women with established CHD, because they are likely to be insulin-resistant, is scientifically unjustifiable and potentially unethical.
Study details
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
Timothy David Noakes
Published in Open Heart 21 July 2021
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 five 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.
Funding:
The Cape Peninsula University of Technology contributes to the costs of the submission and publication of this article. The author 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.
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