Nuts good for fighting obesity and diabetes

The development of obesity and type 2 diabetes can be controlled by a special amino acid, arginine, which is found in nuts.

This sensational discovery has just been made by a group of Danish researchers, who have studied how food, especially nuts, containing arginine affects the body.

“Our studies show that arginine has a number of positive effects, including removing stomach fat and increasing sensitivity to insulin,” says one of the researchers, Christoffer Clemmensen, a PhD student at the Department of Molecular Drug Research at the University of Copenhagen.

Amino acid intake varies with diet

The proteins in our food are made up of almost 20 different amino acids, so the composition of amino acids entering our bodies differs according to the foods we eat – from yoghurt to pork crackling to nuts.

Arginine is found in many foods, and especially in nuts such as coconuts, pecans, cashews, walnuts, almonds, Brazil nuts, hazelnuts, pine nuts and peanuts.

“Together with other amino acids, the arginine we get from our food contributes to the positive impact that arises from eating a diet with the correct protein composition,” says Clemmensen. “But it would be very difficult to eat the arginine quantities that we used in our tests without adding food supplements to our diets.”

Transferring the studies to an everyday situation would mean we must eat almost 20 g of arginine – or 800 g of nuts – every single day, he says. “In time, this discovery can lead to drugs aimed at combating obesity and type 2 diabetes.”

Mice lost stomach fat

Since it is almost impossible to use humans in tests where researchers study how a single amino acid such as arginine affects the body, Clemmensen’s group used mice in two groups, each with ten mice.

Over a period of ten weeks, the two groups were given food with the same distribution of proteins, carbohydrates and fat – but with a significant difference:

• The mice in one group were given food that contained arginine equalling 2 percent of their total energy intake.
• The mice in the other group – the control group – received their 2 percent of total energy intake in the form of a blend of 10 different amino acids, but without arginine.

The researchers then scanned the mice in a magnetic resonance imaging (MRI) scanner, which revealed that the muscles of the mice given arginine had grown and that these mice had less fat around their inner organs.

Tendency for diabetes disappeared

The researchers also tested the tendency of the mice to develop type 2 diabetes, often called adult-onset diabetes. This is characterised in its early stage by reduced insulin sensitivity.

The mice given arginine developed a greater sensitivity to insulin, which protected them against type 2 diabetes.

New drug more effective than arginine

Following their discovery, the researchers started to study why arginine is so beneficial – which needed investigations at the molecular level.

The researchers believe that arginine activates a receptor protein named GPRC6A, which then transmits signals from arginine to the cells in the body that are affected by arginine.

“We wanted to study more thoroughly whether the receptor is actually responsible for the results of our original study,” says Clemmensen. “The longer-term perspective is to make drugs that can activate the receptors better than arginine can, and are therefore more effective than the amino acid.”

More experiments, pills later

Clemmensen cannot say anything about how much time is needed before a slimming and anti-diabetes pill, which imitates the effects of arginine, can be ready for sale.

The next step is to confirm, through further experiments, whether their discovery can actually be coupled to the GPRC6A receptor protein.

Other researchers have already shown great interest in the discovery.

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Read this article in Danish at videnskab.dk

Translated by: Michael de Laine

Scientific links

• Arginine improves multiple physiological parameters in mice exposed to diet-induced metabolic disturbances, Amino Acids, doi: 10.1007/s00726-011-1199-1

External links

• Christoffer Clemmensen’s profile
• Overview of arginine content in foods

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