Dietary replacement of major individual saturated fatty acids with healthier macronutrients is associated with lower risk of coronary heart disease. In particular, the lowest risk was observed with the replacement of palmitic acid.
Saturated fatty acids (SFA) are a well-established risk factor for coronary heart disease. The main individual saturated fatty acids in the diet are lauric acid, myristic acid, palmitic acid and stearic acid, which are differentiated based on chain length and are abundant in different fats and oils. Previous studies have found that individual SFAs had varying effects on blood lipids, but there are limited findings on their contributions to disease risk. In a study published in the BMJ, the association between individual fatty acids and coronary heart disease risk was investigated in two large cohort studies.
The participants were from the Nurses’ Health Studies cohort, which consisted of 73 147 women, and from the Health Professionals Follow-up Study cohort, which consisted of 42 635 men. The participants did not have major chronic illness, such as cancer, diabetes or cardiovascular disease at the beginning of the study. Their food intakes were assessed through food frequency questionnaires that they filled out every 4 years. Furthermore, coronary heart disease cases were obtained through participant follow-up questionnaires and medical records.
After data analysis, the results suggest that higher intakes of lauric acid, myristic acid, palmitic acid and stearic acid were significantly associated with higher risk of coronary heart disease. Furthermore, when energy from these fatty acids were replaced with polyunsaturated fat, monounsaturated fat, whole grain carbohydrates or plant proteins, the disease risk was lowered. The most consumed saturated fat was palmitic acid, which was observed to lead to the lowest disease risk after it was replaced by healthier alternatives. Although a similar association was found in shorter chain fatty acids, these effects were weakened after taking into account the cofounding variables.
These findings support current dietary guidelines on reducing total saturated fat intake with healthier macronutrients. It may be difficult to monitor and select for individual fatty acids, especially when their composition in different foods can vary. In general, animal fats, such as lard or butter, are high in saturated fatty acids, whereas vegetables oils, such as olive oil and canola oil, mostly consist of unsaturated fatty acids. Although saturated fatty acids are still present in vegetable oils, the compositions differ. For instance, palm oil, contains >40% palmitic acid, while coconut oil and palm kernel oil contain >45% lauric acid. Thus, it is possible to identify fatty acid composition in foods in order to minimize its consumption and effectively reduce the risk of coronary heart disease.
Written By: Kim Gotera, BMSc