Saturated and Unsaturated Fats, Carbohydrates, and CHD Risk

Study Questions:

What is the relative coronary heart disease (CHD) risk based on dietary saturated fats as compared with unsaturated fats and different sources of carbohydrates?

Methods:

The authors followed 84,628 women ages 30-55 years (Nurses’ Health Study, 1980-2010), and 42,908 men ages 40-75 years (Health Professionals Follow-up Study, 1986-2010) who were free of diabetes, cardiovascular disease, and cancer at baseline. Diet was assessed by semi-quantitative food frequency questionnaire every 4 years with cumulative averaging over time. Carbohydrates were defined as from whole gains or refined starches/sugars. The primary endpoint was nonfatal myocardial infarction and CHD death obtained via medical records.

Results:

During 24-30 years of follow-up, there were 7,667 incident cases of CHD (~2,700 deaths). Higher intakes of polyunsaturated fatty acids (PUFAs) and carbohydrates from whole grains were significantly associated with lower risk of CHD (hazard ratio) comparing the highest to the lowest quintile for PUFA: 0.80, p trend < 0.0001; and for carbohydrates from whole grains: 0.90, p trend = 0.003. In contrast, carbohydrates from refined starches/added sugars were positively associated with risk of CHD (1.10, p trend = 0.04). Replacing 5% of energy intake from saturated fats with equivalent energy intake from either PUFAs, monounsaturated fats (MUFAs), or carbohydrates from whole grains was associated with 25%, 15%, and 9% lower risk of CHD, respectively (each significant). Replacing saturated fat with carbohydrates from refined starches/added sugars was not significantly associated with CHD risk (p > 0.10).

Conclusions:

The findings indicate that unsaturated fats, especially PUFAs and/or high-quality carbohydrates should replace dietary saturated fats to reduce CHD risk.

Perspective:

Participants generally replaced calories derived from saturated fats with calories from low-quality carbs rather than PUFAs or high-quality carbs. Most impressive is the finding that replacing saturated fats with PUFAs rather than whole grains provides the most CHD risk reduction.

Keywords: Carbohydrates, Coronary Artery Disease, Diet, Energy Intake, Fats, Unsaturated, Fatty Acids, Unsaturated, Myocardial Infarction, Primary Prevention, Risk Reduction Behavior


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