A new study on egg consumption by healthy young adults finds that whole eggs increase beneficial nutrients without negatively impacting markers of heart disease or diabetes. The study also highlights different dietary responses by gender, laying the foundation for future personalized nutrition research. New research broadens understanding of the nutritional effects of eggs when consumed by young, healthy adults.
Are eggs good for the human body?
Scientists have been studying this controversial question for years. Some find that consuming eggs increases LDL, or "bad" cholesterol, and markers of inflammation associated with heart disease and diabetes, while others highlight the benefit of eating eggs because of their nutrient density.
Katherine J. Anderson, associate professor of nutritional sciences in the College of Agriculture, Health and Natural Resources, recently published a study in the journal Nutrients that took a broader look at the nutritional consequences of egg consumption in healthy young adults.
Most existing research articles assessing the health effects of eggs tend to focus on a more limited range of standard clinical measurements, looking at biomarkers of heart disease, diabetes, body composition, inflammation, immune health and anemia in isolation rather than comprehensively. Participants in these studies also tended to have risk factors for chronic diseases. They often also change their eating habits, such as a weight loss program. These factors can complicate interpretation of how eggs affect health markers in average or young healthy people.
Anderson and her collaborators conducted a more comprehensive, clinically focused study that considered many of the health indicators that doctors look for during routine physical exams.
"This helps provide a comprehensive understanding of the effects of egg consumption in young, healthy people using standard routine clinical biomarkers, which we believe can be better generalized to the general population," Anderson said.
Study results on choline and heart disease risk
The study compared eating no eggs, eating three egg whites a day, and eating three whole eggs a day. Participants can cook eggs to their liking.
Anderson found that when participants ate whole eggs every day, blood samples showed a significant increase in the amount of choline, an essential nutrient found in egg yolks. Choline intake has been linked to an increase in a metabolite called TMAO, which has been linked to heart disease. But Anderson's study found that despite increased choline intake, TMAO did not change in this group.
"This is a best-case scenario," Anderson said. "We want to get a lot of this important nutrient, but we don't want to increase this metabolite that may promote cardiovascular disease."
Effects on inflammation, cholesterol and diabetes
The researchers also did not find any adverse changes in inflammation or blood cholesterol levels. They also found that eating whole eggs had less negative impact on markers related to diabetes risk than eating egg whites.
Overall, participants' diets were more nutrient dense when they consumed whole eggs. In addition, they also had higher hematocrit - a measure of the density of red blood cells in the blood - which is lower in people with anemia.
"The fact that we're looking at the full range of measurements allows us to better assess the overall effect of egg intake," Anderson said. "I think that's important because if you see a less positive change in one marker, maybe in context, there will be beneficial changes in other markers as well."
Gender effects and future research
The study included male and female participants. About half of the female participants were taking combined oral contraceptives. This allowed Anderson to study potential differences in nutritional outcomes between women who took birth control pills and those who didn't.
"These are very common medications, and there is a lack of research examining the impact of taking these medications on dietary interventions," Anderson said.
While not all statistically significant, the researchers did observe some differences in this subgroup. Blood samples from female participants who were not taking birth control pills showed a greater increase in the ratio of total cholesterol to high-density lipoprotein cholesterol, which is considered a risk factor for heart disease.
"This is the opposite of what we expected," Anderson said, because hormonal contraceptives are often associated with adverse metabolic changes. But in this case, it seems to have more of a protective effect on the egg."
Female participants who were not taking birth control pills also had a greater increase in monocytes in their blood than those who were taking birth control pills. Monocytes are part of the body's first line of immune defense. Interestingly, changes in clinical immune profiles induced by whole egg consumption were associated with several clinical HDL markers, regardless of drug intake.
This paper is the first in an ongoing series by Anderson examining mechanistic pathways related to egg intake and HDL-immunity relationships. Other questions her lab is studying include the composition of HDL particles and their ability to regulate immune cell activity, as HDL has recently been found to carry hundreds of proteins, not just cholesterol. Anderson also plans to explore differences in nutritional outcomes between older adults and younger adults eating eggs.
Reference: "Consumption of different egg diets alters clinical metabolic and hematological parameters in young healthy men and women" published on August 26, 2023 by Catherine J. Andersen, Lindsey Huang, Fangyi Zhai, Christa Palancia Esposito, Julia M. Greco, Ruijie Zhang, Rachael Woodruff, Allison Sloan, and Aaron R. Van Dyke, Nutrients.
DOI:10.3390/nu15173747
Compiled source: ScitechDaily