Add An Egg for Better Salads
Eggs got a bad reputation back when we thought that high blood cholesterol levels could be controlled through diet. That was because in addition to supplying complete protein (containing all nine essential amino acids), eggs are also significant sources of dietary cholesterol. At the time, scientists had only recently realized that high levels of “bad” LDL-cholesterol were linked to the development of atherosclerosis, the underlying cause of most cardiovascular disease. So they advised people to severely limit their intake of eggs.
But we now know that dietary sources of cholesterol only contribute about 25% to a person’s total blood cholesterol levels. The rest is generated within the body, and it’s primarily controlled by genetics. A further subtlety involves a process called peroxidation. Poor diets often feature lots of simple carbohydrates and fat, and few antioxidants from whole plant foods. Excess oxidation can affect the chemical makeup of one’s LDL-cholesterol, transforming it into a still more dangerous substance through a process called peroxidation. Dietary antioxidants counteract this process, which is one reason plant-based diets tend to be so healthful.
I tell you this to put the following news in context. A Purdue University scientist has published new research which concludes that adding an egg to a salad containing plenty of raw vegetables is a good way to boost one’s intake of the beneficial carotenoid antioxidants in the vegetables. That’s because most of these healthful compounds are fat soluble. If they’re consumed without some additional fat, the body has a difficult time absorbing them.
"Eating a salad with a variety of colorful vegetables provides several unique types of carotenoids, including beta-carotene, lutein, zeaxanthin and lycopene," said Wayne Campbell, a professor of nutrition science. "The lipid contained in whole eggs enhances the absorption of all these carotenoids.”
"Most people do not eat enough vegetables in their diets, and at the same time, people are consuming salad dressings that have less fat or are fat-free," said Jung Eun Kim, a postdoctoral researcher in Purdue's Department of Nutrition Science. "Our research findings support that people obtained more of the health-promoting carotenoids from raw vegetables when cooked whole eggs were also consumed. Eggs, a nutrient-rich food containing essential amino acids, unsaturated fatty acids and B vitamins, may be used to increase the nutritive value of vegetables, which are under consumed by the majority of people living in the United States.”
Don’t skip the cooked egg yolk, though. Although that’s where the cholesterol comes from, it’s also the source of the fats that facilitate carotenoid uptake.
J. E. Kim, S. L. Gordon, M. G. Ferruzzi, W. W. Campbell. Effects of egg consumption on carotenoid absorption from co-consumed, raw vegetables. American Journal of Clinical Nutrition, 2015; DOI: 10.3945/ajcn.115.111062