Egg benefits: Including egg in salads may improve carotenoid absorption
The study, published in the American Journal of Clinical Nutrition and funded by the American Egg Board-Egg Nutrition Center, the National Institutes of Health (NIH) and Purdue University, assessed the absorption of carotenoids from raw vegetables in salads containing canola oil and either egg or no egg.
The absorption of carotenoids was 3.8-fold higher when the salad included three eggs compared to no eggs, said the team – led by first author Jung Eun Kim at Purdue.
"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 Kim. "Our research findings support that people obtained more of the health-promoting carotenoids from raw vegetables when cooked whole eggs were also consumed.”
She added that because eggs are a nutrient-rich food containing essential amino acids, unsaturated fatty acids and B vitamins, they can also be used to increase the nutritive value of a salad.
Study details
The US-based researchers recruited 16 healthy young men to the trial – all of whom consumed the same salad served with 3 g canola oil.
All salads were consumed with either with no egg (control), 75 g scrambled whole eggs (1.5 eggs) [low egg], and 150 g scrambled whole eggs (3 eggs) [high egg] in a randomized crossover design.
“Blood was collected hourly for 10 h, and the triacylglycerol-rich lipoprotein (TRL) fraction was isolated. Total and individual carotenoid contents, including lutein, zeaxanthin , α-carotene, β-carotene, and lycopene in TRL were analyzed, and composite areas under the curve (AUCs) were calculated,” explained Kim and her colleagues.
Professor Wayne Campbell, senior author of the study, explained that the team used scrambled eggs to make sure the participants consumed both the yolk and egg whites – and revealed that the absorption of carotenoids was 3.8-fold higher when the salad included three eggs compared to no eggs.
"While other egg forms were not tested, we believe the results would be comparable as long as the egg yolk is consumed," said Campbell. "The lipids in salad dressings also increase the absorption of carotenoids but it is easy to overuse salad dressings and consume excess calories.”
"Eating a salad with a variety of colourful vegetables provides several unique types of carotenoids, including beta-carotene, lutein, zeaxanthin and lycopene," Campbell added. "The lipid contained in whole eggs enhances the absorption of all these carotenoids."
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.3945/ajcn.115.111062
“Effects of egg consumption on carotenoid absorption from co-consumed, raw vegetables”
Authors: Jung Eun Kim, et al
