Public Comments on the Dietary Guidelines Advisory Committee Report
There are many positive contributions in the Dietary Guidelines Advisory Committee report. Identifying the three healthy dietary patterns—healthy vegetarian, healthy Mediterranean, and healthy U.S—was a major advance. However, the Committee caused considerable confusion in stating that dietary cholesterol is not a “nutrient of concern.” Most members of the public do not differentiate dietary cholesterol from blood cholesterol or the effects of dietary cholesterol from the risks of the foods that contain it. The result has been a green light for unhealthful foods.
In finalizing the Guidelines, it is prudent to retain the dietary cholesterol limit established in previous Guidelines.
So how did this confusion start? The Committee wrote that there is “no appreciable relationship between consumption of dietary cholesterol and serum cholesterol, consistent with the conclusions of the AHA/ACC report.” The Committee was citing a report by the American Heart Association and American College of Cardiology.
However, the AHA/ACC report never said any such thing.1 It summarized evidence published after 1998, and the most recent meta-analyses on this subject were published in 1992 and 1997.2-4 The AHA/ACC report simply called for more research and never said there was no relationship between dietary cholesterol and serum cholesterol. In other words, it does not support the Committee’s statement. And neither do reports from the Institute of Medicine or the Food and Drug Administration, which wrote in 2014 of “the well-established relationship between consumption of cholesterol and its effect on blood cholesterol levels….”
The relationship between cholesterol in foods and cholesterol in the blood was clearly established decades ago and is supported by a robust body of evidence recently summarized by the Institute of Medicine. 5 Using the IOM’s figures, the addition of 100 milligrams of cholesterol (about one half an egg) to the daily diet would boost LDL cholesterol by about 2 mg/dl. That means that the cholesterol in a two-egg breakfast, as part of one’s daily routine, might be expected to boost LDL by about 8 points. However, the effect of increasing cholesterol intake is less evident in people who consume significant amounts of cholesterol from other sources or who maintain high cholesterol levels to start with.
In this graph from the IOM report, each dot is a research study, and the studies above the zero line show that dietary cholesterol raises serum cholesterol. As you can see, nearly all the studies are above the zero line.
“Who cares?” some might say. “A few extra cholesterol points don’t matter too much, do they?” Well the Guidelines are intended as population-wide recommendations. Imagine what even a few extra cholesterol points would mean population-wide. In addition, they apply to childhood which is when cardiovascular disease begins.
For all its good work, the Committee made a scientific error on cholesterol and to carry this glaring mistake into the Guidelines is not scientifically defensible and serves only to perpetuate confusion.
Figure 9.2 from the Institute of Medicine report on Dietary Reference Intakes showing the change in serum cholesterol concentrations (Y-axis) associated with changes in dietary cholesterol.1
1. Eckel RH, Jakicic JM, Ard JD, de Jesus JM, Houston Miller N, Hubbard VS, et al. 2013 AHA/ACC guideline on lifestyle management to reduce cardiovascular risk: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129(25 Suppl 2):S76-99. PMID: 24222015. http://www.ncbi.nlm.nih.gov/pubmed/24222015.
2. Hopkins PN. Effects of dietary cholesterol on serum cholesterol: a meta-analysis and review. Am J Clin Nutr. 1992;55:1060-70.
3. Clarke R, Frost C, Collins R, Appleby P, Peto R. Dietary lipids and blood cholesterol: quantitative metaanalysis of metabolic ward studies. BMJ 1997;314:112-7.
4. Howell WH, McNamara DJ, Tosca MA, Smith BT, Gaines JA. Plasma lipid and lipoprotein responses to dietary fat and cholesterol: a metaanalysis.
Am J Clin Nutr. 1997;65:1747–64.
5. Food and Nutrition Board, Institute of Medicine. Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. National Academies Press, Washington, DC, 2002/2005.
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