A study published in the Journal of the American College of Cardiology shows that replacing saturated fats with unsaturated fats or whole grains may lower the risk of heart disease.
However, replacing saturated fat with refined carbohydrates may not lower the risk of heart disease.Many people fall back on carbs, especially refined carbs like white bread, when they reduce saturated fat in their diets, said senior author Frank Hu, professor of nutrition and epidemiology at Harvard T.H. Chan School of Public Health. "Our research does not exonerate saturated fat," said Hu. "In terms of heart disease risk, saturated fat and refined carbohydrates appear to be similarly unhealthful."
The researchers looked at diet and health information from participants in two long-running trials, the Nurses' Health Study (84,628 women) and the Health Professionals Follow-up Study (42,908 men), who were free of diabetes, cardiovascular disease, and cancer at baseline. Diet was assessed by food frequency questionnaires every four years. During follow-up, the researchers documented 7,667 cases of coronary heart disease (CHD).
They estimated that replacing 5% of energy intake from saturated fats with equivalent energy intake from either polyunsaturated fats, monounsaturated fats, or carbohydrates from whole grains was associated with 25%, 15%, and 9% lower risk of CHD, respectively. On the other hand, swapping 5% of saturated fat calories for the same amount of refined carbohydrates and sugars was not associated with CHD risk. These analyses took into account cardiovascular risk factors such as age, body mass index, smoking, and physical activity.
"Our findings suggest that the low-fat, high-carb trends of the 1980s and 1990s are not effective in reducing risk of CHD," said Yanping Li, co-author and researcher in the Dept. of Nutrition, Harvard T.H. Chan School of Public Health. "It means that individuals should not replace saturated fat with refined carbs or vice versa. Dietary recommendations to reduce saturated fats should specify their replacement with unsaturated fats or with healthy carbohydrates, such as whole grains."