There is a long-standing debate on consumption of eggs and heart health. But findings from a new study indicate that consuming a dozen fortified eggs on a weekly basis does not significantly affect cholesterol levels, compared to a diet with minimal egg intake (two or fewer eggs weekly).
The study was recently presented at the American College of Cardiology’s annual scientific session. While further research is needed, this initial study indicates that fortified eggs may not worsen cholesterol and might even offer some benefits.
Eggs are a common and relatively inexpensive source of protein and dietary cholesterol. For their study, the researchers wanted to look specifically at fortified eggs as they contain less saturated fat and additional vitamins and minerals, such as iodine, vitamin D, selenium, vitamin B2, B5 and B12, and omega-3 fatty acids.
A total of 140 patients with, or at, high risk for cardiovascular disease were enrolled in the PROSPERITY trial. This trial was designed to assess the effects of eating 12 or more fortified eggs a week, versus a non-egg diet (consuming less than two eggs a week) on high density lipoproteins (HDL) and low density lipoproteins (LDL) cholesterol, as well as other key markers of cardiovascular health, over a four-month study period.
“We know that cardiovascular disease is, to some extent, mediated through risk factors like blood pressure, high cholesterol and increased BMI (body mass index) and diabetes. Dietary patterns and habits can have a notable influence on these and there’s been a lot of conflicting information about whether or not eggs are safe to eat, especially for people who have or at risk for heart disease,” said Dr Nina Nouhravesh, a research fellow at the Duke Clinical Research Institute in Durham (North Carolina) and the study’s lead author. “This is a small study, but it gives us reassurance that eating fortified eggs is okay with regard to lipid effects over four months, even among a more high-risk population.”
Selected patients were randomly assigned to eat 12 fortified eggs a week (cooked in the manner they chose) or to eat fewer than two eggs of any kind (fortified or not) per week. All patients were 50 years of age or older (the average was 66 years) and half were women. Also, all had experienced one prior cardiovascular event or had two cardiovascular risk factors, such as high blood pressure, high cholesterol, increased BMI or diabetes.
The co-primary endpoint was LDL and HDL cholesterol at four months. Secondary endpoints included lipid, cardio-metabolic and inflammatory bio-markers and levels of vitamin and minerals.
All patients had in-person clinic visits at the start of the study and periodic visits at one and four months to take vital signs and have blood work done. Additionally, phone check-ins occurred at two and three month intervals and patients in the fortified egg group were asked about their weekly egg consumption. Those with low adherence were provided additional education materials.
In the fortified egg group, analysis of the collected data showed a -0.64mg/dL and a -3.14md/dL reduction in HDL-cholesterol (‘good’ cholesterol) and LDL cholesterol (‘bad’ cholesterol), respectively. While these differences were not significant, the researchers explained that the differences suggest that eating 12 fortified eggs each week had no adverse effect on blood cholesterol.
In terms of secondary endpoint, the researchers observed a numerical reduction in total cholesterol, LDL particle number, another lipid bio-marker called apoB, high-sensitivity troponin (a marker of heart damage) and insulin resistance scores in the fortified egg group, while vitamin B increased.
Explaining that sub-group analyses revealed numerical increases in HDL cholesterol and reductions in LDL cholesterol in patients 65 years or older and those with diabetes in the fortified egg group compared with those eating fewer than two eggs, Dr Nouhravesh said, “While this is a neutral study, we did not observe adverse effects on biomarkers of cardiovascular health and there were signals of potential benefits of eating fortified eggs that warrant further investigation in larger studies as there are more hypothesis generating here.”
In recent times, eggs have received a bad rap due to the confusion that stems from the fact that egg yolks contain cholesterol. The researchers said a more important consideration, especially in the context of these findings, might be what people are eating alongside eggs, such as buttered toast, bacon and other processed meats which are not heart-healthy choices.
Dr Nouhravesh suggests that it’s a good idea for people with heart disease to talk with their doctor about a heart-healthy diet, before making any dietary changes.
It is important to note that the study is limited by its small size and reliance on patients’ self-reporting of egg consumption and other dietary patterns. It was also an unblinded study, i.e., patients knew what study group they were in which can influence their health behaviour.
