In advising patients about a heart-healthy diet, the American Heart Association (AHA) recommends clinicians focus on promoting healthful eating patterns rather than adhering to specific cutoffs for dietary cholesterol intake.1
This move away from limiting cholesterol intake to a certain level has been reflected in recent guidelines from the AHA/American College of Cardiology2 and the Dietary Advisory Committee,3 which no longer recommend a specific dietary cholesterol cutoff of <300 mg/d for the general population and <200 mg/d for patients with hypercholesterolemia. Instead, medical associations have begun to agree that accumulating evidence does not robustly support an association between risk for cardiovascular disease (CVD) and dietary cholesterol intake, often finding mixed results among studies.
This topic was the focus of an AHA science advisory published in Circulation, for which the authors examined existing studies that assessed dietary cholesterol, low-density lipoprotein cholesterol, and CVD risk, as well as potential problems in study methodology that contribute to controversy around the issue.1
After reviewing 17 observational studies from several countries, the advisory statement concluded that most studies did not find significant associations between dietary cholesterol and coronary heart disease or stroke risk, or between egg consumption and risk for coronary heart disease, myocardial infarction, or stroke.
Conversely, some studies did suggest an increased CVD risk with egg consumption, but as these were observational data, potential compounding effects of other dietary components need to be considered, according to the AHA statement.1
The authors also reviewed controlled-feeding intervention studies and noted that they provided more convincing data for an effect of cholesterol intake on CVD risk. In their meta-regression analysis, diets with matched ratios of polyunsaturated fatty acids and saturated fatty acids showed that cholesterol intake significantly affected total cholesterol levels. Still, dietary cholesterol did not predict overall CVD risk or levels of low-density lipoprotein and high-density lipoprotein cholesterol. Furthermore, many intervention studies involved implausibly high cholesterol intakes that were “well above the consumption levels of 95% of the population.”1
With regard to other issues in study methodology, fatty-acid composition was not matched in diets in several of the intervention studies and was not controlled for in most observational studies. This likely made it difficult to distinguish between the independent effects of dietary cholesterol vs fatty acids. In the context of US diets, it is important to consider the effects of both factors, as foods that are high in saturated fat usually contain high levels of cholesterol or accompany high-cholesterol foods in meals.
Taken together, this foundation of evidence suggests that following what is already recommended as a heart-healthy diet in many existing guidelines — one that incorporates whole grains, vegetables, fruits, low- or fat-free dairy products, vegetable oils, lean protein, and nuts — is enough to achieve what is considered to be a healthy level of cholesterol intake (<300 mg/d).
Endocrinology Advisor connected with JoAnn S. Carson, PhD, RDN, FAHA, lead author of the AHA science advisory, to discuss takeaways for physicians.
“I envision that our advice to focus on a healthful dietary pattern rather than pay attention to a specific amount of dietary cholesterol will result in 3 kinds of advice that clinicians give patients,” said Dr Carson. “First, it should reinforce the overall AHA nutrition message that Americans should focus on an overall healthy pattern of food. We do not want to demonize a specific food. But also, eating one specific ‘halo’ food will not overcome the lack of other healthy foods on your plate.”
“Secondly, it should serve as a reference for responding to patients who think that the amount of cholesterol in the diet does not matter. It does matter, and individuals who try trendy diets should still try to keep their dietary cholesterol in line with the typical American who eats less than 300 mg per day.”
“Thirdly, influenced by past advice on healthy eating, many patients want to know, ‘how many eggs can I eat?’ Our answer for a healthy individual would be to include up to about one per day.”
Guidance for egg consumption, specifically egg yolks, was outlined for other groups in the advisory statement as follows:1
- Vegetarians may choose to include more dairy and eggs in their diets within moderation.
- Patients with high cholesterol levels should limit intake of eggs and other cholesterol-rich foods.
- Older patients with normal cholesterol levels may choose to include up to 2 eggs in their diet daily given an otherwise heart-healthy diet.
Dr Carson also provided an outline for heart-healthy plate proportions: one-fourth should be protein foods, with plant-based proteins for some meals; one-fourth grains, preferably whole grains; and one-half vegetables (“eat them, not just serve them!” she emphasized).
“In guiding patients, energy balance should always be part of the underlying message. For overweight or obese patients, choices that include lower-calorie fruits and vegetables, lower-fat protein choices, and plenty of dietary fiber are a good approach, especially when partnered with regular physical activity. Patients who have difficulty adopting a healthy eating pattern may benefit from referral to a registered dietitian/nutritionist,” Dr Carson added.
“A recommendation that gives a specific dietary cholesterol target within the context of food-based advice is challenging for clinicians and consumers to implement; hence, guidance focused on dietary patterns is more likely to improve diet quality and to promote cardiovascular health,” concluded the authors of the AHA advisory.1
1. Dietary cholesterol and cardiovascular risk: a science advisory from the American Heart Association [published online December 16, 2019]. Circulation. doi:10.1161/CIR.0000000000000743
2. Eckel RH, Jakicic JM, Ard JD, 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(suppl 2):S76-S99.
3. Dietary Guidelines Advisory Committee. Scientific report of the 2015 Dietary Guidelines Advisory Committee: advisory report to the Secretary of Health and Human Services and the Secretary of Agriculture. 2015. https://health.gov/dietaryguidelines/2015-scientific-report/. Accessed December 12, 2019.