AHA Plugs ‘Dietary Patterns’ Over Dietary Cholesterol Targets
The new science advisory seeks to dispel confusion around the relevance of dietary cholesterol for heart health.
With a flurry of New Year’s resolutions around the corner, a newly released advisory paper from the American Heart Association (AHA) is seeking to dispel lingering confusion over dietary cholesterol intake that may have arisen when specific targets were eliminated in the recent guidelines.
Instead, the document emphasizes that a diet rich in fruits, vegetables, whole grains, low-fat or fat-free dairy products, lean protein sources, nuts, seeds, and liquid vegetable oils is the better bet for promoting cardiovascular health.
Whereas the 2010 Dietary Guidelines for Americans once put a limit on the consumption of dietary cholesterol at less than 300 mg/day, the 2016 update removed this specific threshold and shifted focus to more general healthy eating patterns.
“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,” write Jo Ann S. Carson, PhD, RDN (University of Texas Southwestern Medical Center, Dallas), and colleagues in their review paper published online in Circulation.
“There's just a lot of confusion out there,” Andrew M. Freeman, MD (National Jewish Health, Denver, CO), who was not involved with the document, told TCTMD, calling the 300-mg cholesterol limit “arbitrary.”
“A lot of people interpreted that as you can have a free for all and eat whatever you want, and that's obviously that's not what the message was,” he said. “You still have to eat well, and diets that are heart healthy are naturally low in cholesterol. So that's the key message there.” What has complicated matters in the interim is that a variety of food industries have spun the removal of the specific cholesterol threshold to mean people can eat however much of a once-limited food item they want, Freeman added.
Stop Counting, Think Holistically
In the paper, Carson and colleagues outline all of the contemporary studies looking at dietary cholesterol as well as egg consumption and cardiovascular risk, including a meta-analysis published in March showing a positive association (HR 1.17; 95% CI, 1.09-1.26). They note some discrepancies in the literature, but ultimately conclude that it “is difficult to distinguish between the effect of dietary cholesterol per se and the effect of dietary patterns high in cholesterol or saturated fat, for example, sausage or bacon eaten with eggs.”
There's just a lot of confusion out there. Andrew M. Freeman
Additionally, studying dietary cholesterol can be complicated by the type of dietary fat included, they write. “In many intervention studies, the fatty acid composition of the diets was not matched; likewise, because the majority of observational studies do not adjust for saturated, monounsaturated, and polyunsaturated fat, it can be difficult to distinguish between the independent effects of dietary cholesterol and dietary fat type.”
There are two aspects of diet that cannot be ignored when considering the relationship between dietary cholesterol and risk of cardiovascular disease, the authors conclude. “First, most foods contributing cholesterol to the US diet are usually high in saturated fat or consumed with foods high in saturated fat. Second, heart-healthy dietary patterns (eg, Mediterranean-style and DASH-style diets) are inherently low in cholesterol, with typical menus containing < 300 mg/d cholesterol, similar to the current US intake.”
Freeman added that there are variations in metabolisms among people, giving the example that some can eat eggs without increasing their cholesterol and others have trouble doing so. “There are some studies from a long time ago that basically showed that if you're eating a standard American diet and you add a few eggs, your overall cholesterol number may not go up very much,” he said. “But if you're not used to eating that amount and then you suddenly eat some, your cholesterol can go up quite a bit, and I think that's the distinction.”
Ultimately, “it's not so important to count the amount of cholesterol that one's consuming, . . . but there does seem to be an increased risk of cardiovascular events when people are consuming lots of eggs,” Freeman said.
For physicians advising patients with known cardiovascular disease, “the evidence to date, at least in my mind, still significantly pushes us toward a predominantly low fat, whole food, plant-based diet,” he concluded. “And then if you have a patient that's particularly high risk, you might really want to push them to being very, very strict and not having lots of shellfish or eggs or whatever it may be.”
Carson JS, Lichtenstein AH, Anderson CAM, et al. Dietary cholesterol and cardiovascular risk: a science advisory from the American Heart Association. Circulation. 2019;Epub ahead of print.
- Carson and Freeman report no relevant conflicts of interest.