Protein—Not Sugar— Keeps Us Alert

Having a drowsy day owing to a poor night’s sleep? You might want to reconsider layering that sugary strawberry jam on your nut-buttered toast and opt for the more protein-rich solo version. Better yet, have an egg-white omelette full of veggies. The protein may just give your cells the kick start they need to get your system in gear.

A new study in the November 17, 2011, issue of the journal Neuron has found that protein—not sugar—stimulates the cells responsible for keeping us alert and burning calories. It could have implications for understanding obesity and sleep disorders, stated the authors, led by Denis Burdakov, PhD, of the department of pharmacology and Institute of Metabolic Science at the University of Cambridge, England.

Wakefulness and energy expenditure rely on “orexin cells,” which secrete a stimulant called orexin/hypocretin in the brain. Reduced activity in these unique cells results in narcolepsy and has been linked to weight gain.

Researchers compared effects of different nutrients on orexin cells. They found that amino acids—nutrients found in proteins such as egg whites—stimulate orexin neurons much more than other nutrients. Previously, the researchers had discovered that glucose blocks orexin cells (which could be why we sometimes feel sleepy after eating); this led the group to study interactions between sugar and protein. They found that amino acids stop glucose from blocking orexin cells. In plain terms, this means protein negates sugar’s effects on cells.