Heart disease accounts for about 25% of all deaths in the United States, with almost 600,000 Americans dying from it each year (1). It has been among the top five leading causes of death in the United States since 1935 (2). From the time the first set of dietary goals for Americans was issued in 1977, reducing intake of dietary cholesterol and saturated fat has been advised because they were thought to increase risk of developing and dying from heart disease (3). As a result, nutrition recommendations have advised a higher carbohydrate, lower fat, and lower cholesterol diet.
However, since heart disease remains one of the leading causes of death today and incidence of other chronic diseases have increased, several questions arise. Does dietary cholesterol and saturated fat intake really have an impact on cardiovascular disease? Are people doing themselves more harm than good by eating a higher carbohydrate diet just to decrease intake of cholesterol and saturated fat?
Both cholesterol and fatty acids (including saturated fat) perform functions in the human body. Cholesterol synthesizes cell membranes, steroid hormones (including vitamin D) and bile acids. In most people, production by the liver and absorption of cholesterol will automatically adjust based on what is available in the diet and needed by the body to maintain homeostasis (4). Fatty acids are a major part of the phospholipid component of cell membranes, are needed to transport and absorb fat-soluble vitamins, and are used as a fuel source.
It has been accepted that high intakes of cholesterol and saturated fats raise total cholesterol and LDL-cholesterol levels, which increased risk (or even caused) cardiovascular disease. However, only about 25% of people experience a significant rise in plasma cholesterol levels (both LDL and HDL) after consuming foods high in cholesterol, such as eggs, (5, 6, 7). In addition, several large epidemiologic studies, including the Framingham Heart Study, the Lipid Research Clinics Study, the Health Professionals Study, and the Nurses’ Health Study found no significant association between dietary cholesterol intake and cardiovascular disease risk or death (5). Additionally, a meta-analysis of 21 prospective epidemiologic studies showed no significant association between saturated fat intake and increased risk of cardiovascular disease (8).
It has been suggested that there are more useful indicators in evaluating cardiovascular risk. Rather than total and LDL-cholesterol, the LDL/HDL ratio may be a better marker (5), which does not seem to be negatively impacted by dietary cholesterol and saturated fat intake. Another marker that has been studied for years but is not widely discussed is LDL particle size. Smaller, denser LDL particles are more atherogenic than larger LDL particles (7,9, 10). They appear to correspond with intake of dietary carbohydrates, particularly simple sugars and high glycemic starches (11) and are associated with high triglyceride levels, low HDL-cholesterol levels and abdominal fat (9), all of which are risk factors for metabolic syndrome.
Recent research that analyzed studies from 1957 to 2013 also found that simply lowering dietary fat and cholesterol is not likely to provide the most benefit in reducing risk for cardiovascular disease (12). Emphasis on higher quality diets including less processed whole foods rather than focusing on one element such as limiting fat, cholesterol, calories or portions will likely produce more long-term health benefits and reduce risk for other chronic diseases as well.
Written by Michelle Baglio of Optimal Nutrition and Health (Google+). The information contained in this post is provided for educational purposes only with the understanding that Optimal Nutrition and Health makes no warranties, either expressed or implied, concerning the accuracy, completeness, reliability, or suitability of the information. Readers are advised not to use information in this post or others found on this website for the treatment or prevention of disease, and it should not be used in place of medical treatment or advice. Please do not reprint this post for distribution without my permission. To feature on your website or social media, please link to this post as the original source.