Featured article in the Spring 2017 Issue of Nutrition Close-Up; written by Lynn Cofer-Chase, MSN, CLS, FAHA, FPCNA, FNLA
It is well-known that high cholesterol levels in our blood, particularly high low-density lipoprotein cholesterol (LDL-C) (i.e., the bad cholesterol) levels, increase our risk for heart disease, bypass surgery, etc. And it seems logical that eating animal foods that have atypically high amounts of cholesterol, such as egg yolks and organ meats, would worsen blood cholesterol levels thereby increasing our risk for heart attack.
Based on that assumption, back in 1961, American Heart Association (AHA) experts recommended that adults should reduce intake of cholesterol.1 By 1968, they set a 300 mg per day limit for patients known to have high cholesterol blood levels.2 In 2001, the National Cholesterol Education Program guidelines recommended that patients at high risk limit cholesterol intake to less than 200mg/day.3
Although heart disease hasnt changed, dietary recommendations related to the intake of dietary cholesterol have recently changed drastically from those in the past. Current recommendations are now based on science rather than assumption. Studies were designed to see if this logical assumption was indeed true. One study, called the Harvard Egg Study, was specifically designed to see if dietary cholesterol actually increased the risk of cardiovascular disease. Although there was a slight trend for blood cholesterol levels to increase with increased intake of dietary cholesterol, it was modest and appeared to vary from person to person. Results led authors to conclude that the earlier purported adverse relationship between dietary cholesterol and heart disease risk was likely largely over-exaggerated.4
By 2013, the American College of Cardiology (ACC) teamed up with experts from the AHA and agreed that recommendations should be based on evidence provided by scientific trial data. Hence, they decided to define levels of evidence for each and every recommendation. If no sufficient scientific study evidence was available, they would not formulate a recommendation. This led to the statement in the 2013 ACC/AHA Guidelines on Lifestyle Management to Reduce Cardiovascular Risk that There is insufficient evidence to determine whether lowering dietary cholesterol reduces LDL-C.5
The 2015 Dietary Guidelines Advisory Committee could not find cause to state a quantitative limit on dietary cholesterol intake. Their report stated that more research is needed regarding a doseresponse relationship between dietary cholesterol and blood cholesterol levels.6 Therefore, the 2015- 2020 Dietary Guidelines for Americans dropped the previous recommendation to limit dietary cholesterol intake to 300 mg per day. The National Lipid Associations (NLA) review of the scientific literature revealed only modest effects of dietary cholesterol on cholesterol levels.7 The NLA report included information from a controlled feeding study stating that each 100 mg/day of dietary cholesterol raised LDL-C by an average of about 1.9 mg/dL.7 Additionally no association between dietary cholesterol or egg consumption (a large contributor to dietary cholesterol intake) and atherosclerotic cardiovascular disease risk in the general population was found.7
So does all this mean that if we eat 3 eggs per day like Emma Morano, who began doing so in childhood, well also celebrate our 117th birthday? No. But, can we let go of our fear that eating eggs will increase our cholesterol levels and heart attack risk? That does appear to be the case. A meta-analysis recently published in the Journal of the American College of Nutrition suggests eating one egg a day reduces risk of stroke by 12 percent and does not affect risk for coronary heart disease.8 Authors went on to say that Eggs are a relatively low cost and nutrient-dense whole food that provides a valuable source of protein, essential fatty acids, antioxidants, vitamins & minerals.8 Enjoy that egg now to your hearts content!
REFERENCES
1. American Heart Association, Circ 1961; 23:133-136
2. American Heart Association, 1968
3. National Cholesterol Education Program, NIH Publication No. 01-3670, May 2001
4. Jones,PJH. Int J Clin Pract 2009;63:1-8
5. Eckel RH et al. Circ 2014;129:576-599
6. US Dept Health & Human Services and Department of Agriculture. 2015-2020 Dietary Guidelines for Americans http://health.gov/dietaryguidelines/2015/guidelines/
7. Jacobson TA et al. J Clin Lipid 2015;9:S1-S122
8. Alexander, DD et al. J Am Coll Nutr 2016;35(8):704-716