As a Nutrition expert I sometimes find it hard to keep on top of the new (and often conflicting) information coming out around macronutrients. Of particular interest at the moment is protein, you may have noticed some of the bad press protein has been getting with regard to its potential link to cancer and obesity if consumed in excess. The findings of this study are yet to be fully published, but are so far rather alarming, especially when you consider that protein is an integral nutritional component to the human body. The ‘Meat & Cheese may be as bad as smoking’ study led by Suzanne Wu is alarming, and is a study I intend on critiquing quite heavily once it’s published, but that’s one for tomorrow! In the mean time I want to allude to another recent study by Burdakov and other scientists from Cambridge University which picks up on the 3pm slump many of you may feel on a day to day basis, and what you can do to overcome it.
Protein not sugar stimulates cells
The new study published in the scientific journal Neuron suggests that it’s protein and not sugar that keeps us awake and burning calories. Wakefulness and energy expenditure rely on orexin cells, these cells are responsible for secreting orexin or hypocretin in the brain. Reduced activity in these cells has previously been linked to narcolepsy (sleeping disorder effecting brains ability to regulate a normal sleep-wake cycle) and weight gain.
How different nutrients effect orexin cells
The researchers found that amino acids found in protein sources such as meat and eggs stimulate orexin neurons more than other nutrients. The lead researcher Dr Burdakev explains that “Sleep patterns, health, and body weight are intertwined. Shift work, as well as poor diet, can lead to obesity,” demonstrating a link between the two. He goes on to explain that “Electrical impulses emitted by orexin cells stimulate wakefulness and tell the body to burn calories. We wondered whether dietary nutrients alter those impulses.”
The scientists used fluorescent dyes which highlight the orexin cells in mice, this enabled the scientists to see neurological responses to the introduction of certain nutrients. Interestingly the scientists highlighted glucose as an inhibitor of orexin cells, which goes some way to explaining post meal sleepiness (as well as the preferential shift of blood from the brain to the stomach after eating). However, the researchers did notice that the consumption of glucose in the presence of amino acids stopped glucose from blocking orexin cells. Consequently protein negates the effects of sugar on the cells. This could also be a reason why people feel more alert and less calm after high protein meals!
Dr Burdakov said. “Not all brain cells are simply turned on by all nutrients, dietary composition is critical”. “To combat obesity and insomnia in today’s society, we need more information on how diet affects sleep and appetite cells. For now, research suggests that if you have a choice between jam on toast, or egg whites on toast, go for the latter! Even though the two may contain the same number of calories, having a bit of protein will tell the body to burn more calories out of those consumed.”
Burdakov, D. (2011). 3pm slump? Why a sugar rush may not be the answer. Neuron. Retrieved 5th March, 2014, from http://www.cam.ac.uk/research/news/3pm-slump-why-a-sugar-rush-may-not-be-the-answer