1.
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.
Noakes, TD
Open heart. 2021;(2)
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.
2.
Rising to the challenge of the new NCEP ATP III guidelines: exceeding current therapeutic limitations.
Brewer, HB
The American journal of managed care. 2002;(2 Suppl):S23-8; discussion S45-7
Abstract
The third set of guidelines recently issued by the National Cholesterol Education Program (NCEP) differs from the second set issued in 1993 in several ways. The third set introduced a quantitative risk scoring system and identified and/or reclassified certain groups of patients at high or moderate risk for a coronary event. Among these groups are patients with type 2 diabetes, and patients with multiple risk factors other than coronary heart disease or diabetes that cumulatively confer high risk for a coronary event. However, the new guidelines also present physicians with the major challenges of identifying these patients, determining their true risk, and implementing the recommended approaches to treatment in clinical practice settings. Although reducing elevated levels of low-density lipoprotein (LDL) cholesterol remains the primary focus of therapy, the new NCEP guidelines also include strategies to identify and treat patients with low levels of high-density lipoprotein (HDL) cholesterol and/or elevated triglyceride levels. Just as there is "good" cholesterol (HDL) and "bad" cholesterol (LDL), there are also "good" triglycerides, which contain high concentrations of triglyceride remnants and are associated with low risk, and "bad" triglycerides, which contain high concentrations of cholesterol remnants and are associated with increased risk. The mechanisms by which "bad" triglycerides develop explain why elevated triglycerides and low HDL--and patients with the metabolic syndrome--warrant special attention. These mechanisms and others also suggest new targets for therapeutic intervention and the development of new drugs that will correct lipid and lipoprotein abnormalities through a number of different metabolic pathways.