Many researches have recommended a diet rich in protein can help weight loss. Now, investigators have revealed the fundamental mechanisms of this link, which may open the door to new preventive and therapy strategies for obesity.
In a new pilot research, investigators from Imperial College, London , in the United Kingdom show how phenylalanine – an amino acid produced by the digestion of protein – increases levels of a hormone that makes us realise when we are full, resulting in decreased food consumption.
Lead author Mariana Norton presented their study outcomes on 9th Nov, 2016 at the Society for Endocrinology annual meeting in the U.K.
Earlier studies have proven that a diet high in protein – essential nutrients identified in foods such as milk, fish, eggs, and poultry – can assist decrease body weight by controlling appetite.
Norton and her team say that a rich protein diet can be difficult to adhere to, but discovering the mechanisms by which protein reduces hunger could result in simpler weight-loss approaches.
How phenylalanine results in weight loss?
For their research, the investigators performed a number of tests on rodents, which involved examining the effects of phenylalanine.
Phenylalanine is an enzyme generated in the gut after intake of foods high in protein.
Initially, the research team administered 10 mice and rats a single dose of phenylalanine and compared them with those that were not.
The investigators identified that mice and rats provided phenylalanine demonstrated enhanced levels of the hormone GLP-1, which suppresses appetite, but decreased levels of the hormone ghrelin, which boosts hunger.
In addition, the investigators identified that phenylalanine decreased the rodents’ food consumption and enhanced weight loss. Rats that obtained the enzyme also moved around more, which the study team notices may have led to their weight loss.
Next, the team gave regular doses of phenylalanine to mice with diet-induced obesity over a 7 day period.
In comparison with mice that were not treated with phenylalanine, those that received the enzyme revealed a decrease in weight, the investigators report.
Phenylalanine promotes CaSR receptor to reduce appetite
In a final experiment, the investigators desired to acquire a better understanding of the mechanisms by which phenylalanine impacts levels of GLP-1 and ghrelin.
On applying phenylalanine to gut cells in a petri dish, the study team identified that the enzyme focuses on a receptor known as the calcium-sensing receptor (CaSR), and it is this receptor that raises GLP-1 levels and decreases levels of ghrelin.
Norton and her study team stated that their results may fuel much required new approaches to deal with the obesity epidemic.
Commenting on their research Norton said,
“Our work is among the first ones to show that triggering CaSR can reduce appetite. It illustrates the possible use of phenylalanine or other molecules which stimulate CaSR – like medicines or food components – to protect against or treat obesity.”