Jo Ann Carson, PhD, RDN, on Dietary Cholesterol and CV Risk

The American Heart Association recently issued a science advisory on dietary cholesterol and cardiovascular risk.

Published in Circulation, the new advisory places emphasis on the importance of healthy dietary patterns that are inherently relatively low in cholesterol, such as the Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diets, rather than recommending a specific dietary cholesterol target, which the authors note “is challenging for clinicians and consumers to implement.”

Nutrition411 discussed the advisory and its implications further with lead author Jo Ann Carson, PhD, RDN. Dr Carson is one of the chairs of the new advisory.

Nutrition411: There is a wealth of evidence suggesting the benefits of heart-healthy diets, but adherence to these diets can be difficult in the United States, where the Western diet is highly prevalent and the rates of overweight and obesity are very high. What can dietitians do to help empower their patients to consume a more heart-healthy diet?

Dr Carson: I think it is important to give patients simple messages about actions they can take in a stepwise fashion towards a heart-healthy diet. When a dietitian is working one-on-one with a client, it is important to find out where they are in terms of dietary intake, and then move forward with a plan. For patients who eat almost no fruits or vegetables, give them tips that will work for their lifestyle to include 1 or 2 vegetables a day.

For patients who are doing reasonably well but want to further improve their health, especially if they are trying to manage their blood cholesterol levels with diet and exercise rather than medication, it is helpful to give them specific tips related to the fruit and vegetable selections they are making, such as ensuring that their vegetables are not cooked with unhealthy fats, etc.

Another important step dietitians can take is to help dispel misinformation. Sometimes, patients want to go to extreme lengths to improve their diet, but end up creating habits that are not beneficial to them.

N411: There has been a lot of controversy related to eggs in recent years. What should dietitians recommend to patients when it comes to consumption of eggs and other forms of dietary cholesterol?

Dr Carson: The message of our advisory is that, if you focus on heart-healthy dietary patterns, and if you are making wise selections within each food group, you do not need to count milligrams of cholesterol, which is a practice that has been common among dietitians for years. In fact, I used to teach students to do this. Instead, focusing on heart-healthy dietary patterns is most important.

The egg issue is really unique because, unlike many other sources of dietary cholesterol, eggs are lower in saturated fat and contain high-quality protein, phytochemicals, and vitamins. General dietary advice for healthy individuals is that one egg a day with the yolk is acceptable. For patients who may want to boost their protein intake, or for vegetarians relying on eggs for protein, incorporating more egg whites works well. For example, when making scrambled eggs, 2 egg whites and 1 whole egg can be used in order to avoid consuming high amounts of dietary cholesterol.

N411: What key takeaway do you hope to leave with dietitians on this topic?

Dr Carson: The key message is that, although we had a cut point of 200 to 300 mg cholesterol per day in the past, we are no longer trying to focus on a specific amount of dietary cholesterol per day. Instead we want patients to focus on pursuing heart-healthy dietary patterns.

Another key point of the advisory is that dietary cholesterol does matter. We do not want patients to think that there is no cut point for dietary cholesterol and they can eat as much of it as they want. Some patients can be harmed if they go overboard on dietary cholesterol in their diet.

In the end, though, patients’ dietary patterns should incorporate less than 300 mg cholesterol per day. If we can encourage patients to focus on the foods they are selecting and make wise choices, they should end up within this range in terms of daily dietary cholesterol intake.

N411: What are the next steps in terms of future research on dietary cholesterol?

Dr Carson: It would be ideal if we could look further into the effects of modifying aspects of a heart-healthy dietary pattern on cardiovascular risk factors, as well as cardiovascular disease (CVD) outcomes themselves. For instance, in an otherwise heart-healthy diet, does increasing dietary cholesterol affect CVD outcomes? However, such intervention trials would be very expensive and time-consuming.

When utilizing observational data, it would be helpful if food frequency questionnaires were updated to capture newer foods trends, such as consumption of various forms of cooking oils, non-dairy “milks”, lean vs fatty cuts of red meats, and use of meat alternatives, including some of the new ones that include substantial saturated fat from plant sources. Also, it would be valuable to capture subjects’ cardiovascular risk profile, including not only their serum lipid profile, but use of medications and physical activity.

Another avenue of investigation would be to assess the impact of nutrition advice on the overall healthfulness of dietary intake.  For instance, do messages that eliminate a quantitative limit on cholesterol intake result in not only greater intake of cholesterol from eggs, but perhaps increased saturated fat from breakfast meats that accompany the eggs? Another question would be, does advising a patient to reduce saturated fat intake contribute to a more optimum energy intake in the patient?

—Christina Vogt

Reference:
Carson JAS, Lichtenstein AH, Anderson CAM, et al. Dietary cholesterol and cardiovascular risk: a science advisory from the American Heart Association. Circulation. 2019;140. doi:10.1161/CIR.0000000000000743.