Replacing Saturated Fats and Sugary Carbohydrates With Unsaturated Fats Reduces Risk of Coronary Heart Disease

Replacing saturated fatty acids (SFAs) with polyunsaturated fatty acids (PUFAs), monounsaturated fatty acids (MUFAs), or carbohydrates from whole grains was associated with lower coronary heart disease (CHD) risk, according to research published in the Journal of American College of Cardiology.

In addition, the researchers, led by Yanping Li, PhD, from the Department of Nutrition at the Harvard T.H. Chan School of Public Health in Boston, observed that replacing carbohydrates from refined starches or added sugars with PUFAs or carbohydrates from whole grains was also associated with a lower CHD risk.

The participants included 84 628 women from the NHS (Nurses’ Health Study) from 1980 to 2010 and 42 908 men from the HPFS (Health Professionals Follow-up Study) from 1986 to 2010. They provided information about their diet and lifestyle factors, medical history, and newly diagnosed diseases through self-administered mailed Food Frequency Questionnaires (FFQs) at baseline and every 2 to 4 years thereafter. Participants from NHS completed an FFQ a total of 6 times and in the HPFS, the FFQ was administered every 4 years.

Analysis of carbohydrates was divided into 2 main groups: carbohydrates from whole grains, and carbohydrates from refined starches or added sugars, mainly including foods with relatively high Glycemic Index values, such as potatoes, refined grains, and added sugar from beverages and foods.

The study’s primary end points were non-fatal myocardial infarction and death from cardiovascular disease, which were identified primarily through a review of medical records.

SFAs, MUFAs, and PUFAs, and trans fats were each significantly associated with a risk of CHD. A higher intake of PUFAs was associated with a lower risk of CHD (for highest vs lowest quintiles, hazard ratio [HR]: 0.80; 95% confidence interval [CI]: 0.73-0.88; P<.0001), whereas trans fats were significantly associated with an increased risk of CHD (HR: 1.20, 95% CI: 1.09-1.32; P=.002). In analyzing different sources of carbohydrates, the risk of CHD was significantly lower when energy was consumed from carbohydrates from whole grains (HR: 0.90; 95% CI: 0.83-0.98; P=.003) and significantly higher when consumed from carbohydrates from refined starches or added sugars (HR: 1.10; 95% CI: 1.00-1.21; P=.04).

“In our study, replacing saturated fatty acids with monounsaturated fatty acids was associated with a lower coronary heart disease risk, suggesting that there are healthful benefits to replacing food sources of saturated fats with plant sources of monounsaturated fatty acids, such as vegetable oils (eg, olive oil and canola oil), nuts, and seeds,” the researchers wrote.

Although whole-grain consumption has increased in recent decades, it is still quite low. Less than 5% of people in the United States consume the recommended amount per day, which amounts to about 3 ounces.

These study results indicate that diet recommendations to reduce consumption of SFAs should specify replacing them with unsaturated fats and/or high-quality carbohydrates.

Reference

1. Li Y, Hruby A, Bernstein AM, Ley SH, et al. Saturated Fats Compared With Unsaturated Fats and Sources of Carbohydrates in Relations to Risk of Coronary Heart Disease: A Prospective Cohort Study. Journal of the American College of Cardiology. 2015; doi.org/10.1016/j.jacc.2015.07.055.