Crack open your kindness: Eating eggs helps people shell out when it come to charity.

Serotonin, the happy hormone, turns you into a good egg. And eating eggs activates serotonin.

Eggs, it turns out, might also activate your charity instinct.

In an unusual study, researchers decided to find out how much more charitable we become after eating eggs.

They already understood that serotonin, as well as maintaining mood balance and our sense of happiness, is associated with social behaviour – acts of generosity and kindness, for instance.

The researchers also knew that an amino acid, called tryptophan (TRP) – found in whole eggs, poultry, beans, oats, fish, cheese, tofu, seeds and nuts – converts into serotonin in the body.

Now the researchers, from Leiden Institute for Brain and Cognition in The Netherlands, have found that eating foods full of Tryptophan can increase our willingness to give to charity by as much as double.

"For the first time, we investigated whether the administration of a compound contained in food such as fish, eggs, soy and milk, can promote charitable donating," said the Dutch authors.

"Our study is the first demonstration that charitable donating can be enhanced by serotonin-related food supplements."

The team took 32 healthy students and gave half the group a placebo and the other half the equivalent TRP of three eggs.

All participants were instructed not to eat or drink anything other than water the night before the experiment mornings. They were also required to refrain from alcohol or drug use for the duration of the study's period.

The students were given $15 each for their participation in the study and were asked whether they would like to leave any of their reward to charity.

Those who took the TRP donated, on average, double the amount donated by the placebo participants.

The study was admittedly small and the authors acknowledged that more research was needed to see if the results could be replicated.

Their results however, support the idea that "you are what you eat", they said.

"[This is] the idea that the food one eats has a bearing on one's state of mind," the authors concluded.

"The food we eat may thus act as a cognitive enhancer that modulates the way we deal with the 'social' world."

Other recent research has debunked the idea that eggs are bad for heart health and cholesterol in healthy individuals. In fact, eggs are rich in iodine, for making thyroid hormones, and phosphorus, which is essential for healthy bones and teeth. They are also packed with vitamins A, B, E and D.

Government guidelines recommend eating one to three serves of eggs, nuts, legumes or poultry a day. One serve is the equivalent of two large eggs.

Head to our Facebook page for more from Stuff Life & Style