Saturated Fats Compared With Unsaturated Fats and Sources of Carbohydrates in Relation to Risk of Coronary Heart Disease: A Prospective Cohort Study

Background: The associations between dietary saturated fats and the risk of coronary heart disease (CHD) remain controversial, but few studies have compared saturated with unsaturated fats and sources of carbohydrates in relation to CHD risk.

Objectives: This study sought to investigate associations of saturated fats compared with unsaturated fats and different sources of carbohydrates in relation to CHD risk.

Methods: We followed 84,628 women (Nurses' Health Study, 1980 to 2010), and 42,908 men (Health Professionals Follow-up Study, 1986 to 2010) who were free of diabetes, cardiovascular disease, and cancer at baseline. Diet was assessed by a semiquantitative food frequency questionnaire every 4 years.

Results: During 24 to 30 years of follow-up, we documented 7,667 incident cases of CHD. Higher intakes of polyunsaturated fatty acids (PUFAs) and carbohydrates from whole grains were significantly associated with a lower risk of CHD comparing the highest with lowest quintile for PUFAs (hazard ratio [HR]: 0.80, 95% confidence interval [CI]: 0.73 to 0.88; p trend <0.0001) and for carbohydrates from whole grains (HR: 0.90, 95% CI: 0.83 to 0.98; p trend = 0.003). In contrast, carbohydrates from refined starches/added sugars were positively associated with a risk of CHD (HR: 1.10, 95% CI: 1.00 to 1.21; p trend = 0.04). Replacing 5% of energy intake from saturated fats with equivalent energy intake from PUFAs, monounsaturated fatty acids, or carbohydrates from whole grains was associated with a 25%, 15%, and 9% lower risk of CHD, respectively (PUFAs, HR: 0.75, 95% CI: 0.67 to 0.84; p < 0.0001; monounsaturated fatty acids, HR: 0.85, 95% CI: 0.74 to 0.97; p = 0.02; carbohydrates from whole grains, HR: 0.91, 95% CI: 0.85 to 0.98; p = 0.01). Replacing saturated fats with carbohydrates from refined starches/added sugars was not significantly associated with CHD risk (p > 0.10).

Conclusions: Our findings indicate that unsaturated fats, especially PUFAs, and/or high-quality carbohydrates can be used to replace saturated fats to reduce CHD risk.