By Biplab Das

Adding eggs to a carbohydrate-restricted diet (CRD) regime increases the serum level of high-density lipoprotein bound cholesterol (HDL-C) without increasing the LDL-C, reports a research team from the University of Connecticut. HDL,  also kown as good cholesterol, removes cholesterol from plaques inside the arteries and ferries it back to the liver for excretion or re-utilization, thereby cutting down the risks of cardiovascular diseases.

Carbohydrate-restricted diet is suggested to reduce body weight, waist circumference and plasma fats, factors associated with metabolic syndrome and cardiovascular diseases.

The researchers wanted to see if adding egg, which is high in protein and cholesterol but low in carbohydrate, to a CRD regime had any effect on the benefits of CRD on metabolic syndrome related factors.

In recent years, overweight and obesity have been major health problems in the Unites States. Researchers attribute this partly to genetic disposition and partly on unhealthy lifestyle. Increased sedentary lifestyle, of both adults and children, makes one prone to metabolic syndrome (MetS) and cardiovascular diseases. MetS is a group of conditions that put one at risk for heart disease and diabetes. These conditions are high blood pressure, high blood sugar levels, high levels of triglycerides (a type of fat in blood), low levels of HDL and too much fat around waist.

Consumption of eggs has been shown to offer a host of nutritional benefits. In addition to folate, eating eggs leads to daily higher intakes of vitamins C, E, and B12. Deficiencies in these vitamins have been associated with increased risk of cancer, cardiovascular disease and Alzheimer’s disease. Research has shown that eggs provide a significant amount of the carotenoids lutein and zeaxanthin, which have been suggested to prevent age-related macular degeneration, a cause of blindness among people over the age of 60.

The study was carried out on 28 men aged between 40 and 70 years; 15 subjects consumed 3 liquid eggs per day (EGG) and 13 subjects consumed the same amount of egg substitute (SUB) on top of their CRD regime. The EGG group consumed 640 mg/day additional dietary cholesterol as compared to the zero cholesterol on the SUB group. Three eggs are the equivalent to 1.76 gram (g) carbohydrate, 18.95 g protein, 22.99 g fat, and cholesterol or fat-free eggs are the equivalent to 2.90g-carbohydrate19.79 g protein, 0.31 g fat.

The subjects were on the diet regime for 12 weeks and followed their normal physical activity.

In the EGG group, dietary cholesterol increased, whereas in the SUB group it did not change. Thirteen in the EGG group showed a rise in HDL-C concentrations. On the other hand, only 3 in the SUB group had increased HDL-C concentrations. At the beginning of the study, there were 18 subjects having MetS. At the end of the study, only 3 subjects from SUB group were found to be categorized as having MetS.

The present study shows that including eggs as part of low carbohydrate diet increased the good cholesterol (HDL), which protects against LDL-mediated formation of plaques inside the artery walls. Such plaques increase the risks of cardiovascular diseases.

The researchers concluded that the additional 3 eggs per day to the CRD diet did not compromise its benefits on reducing risk factors associated with metabolic syndrome.

The study was published in the Journal of Nutrition on the February 2008 edition*.


*Gisella Mutungi, Joseph Ratliff, Michael Puglisi, Moises Torres-Gonzalez, Ushma Vaishnav, Jose O. Leite, Erin Quann, Jeff S. Volek and Maria Luz Fernandez. Dietary Cholesterol from Eggs Increases Plasma HDL Cholesterol in Overweight Men Consuming a Carbohydrate-Restricted Diet. Journal of Nutrition, February 2008; 138: 272-276 .

Christine M Greene, David Waters, Richard M Clark, John H Contois and Maria Luz Fernandez. Plasma LDL and HDL characteristics and carotenoid content are positively influenced by egg consumption in an elderly population. Nutrition & Metabolism. January 2006; Vol. 3, Issue. 1.