In a major study, the researchers have revealed that performing acts of kindness and helping other people can be good for people's health and well-being.

According to the study, published in the journal Psychological Bulletin, the strength of the link depends on many factors, including the type of kindness, the definition of well-being, and the giver's age, gender and other demographic factors.

"Prosocial behaviour–altruism, cooperation, trust and compassion–are all necessary ingredients of a harmonious and well-functioning society," said study lead author Bryant PH Hui from the University of Hong Kong.

"It is part of the shared culture of humankind, and our analysis shows that it also contributes to mental and physical health," Hui added.

Previous studies have suggested that people who engage in more prosocial behavior are happier and have better mental and physical health than those who don't spend as much time helping others.

However, not all studies have found evidence for that link, and the strength of the connection varies widely in the research literature.To better understand what drives that variation, the research team performed a meta-analysis of 201 independent studies, comprising 198,213 total participants, that looked at the connection between prosocial behavior and well-being. Overall, they found that there was a modest link between the two. Although the effect size was small, it is still meaningful, according to Hui, given how many people perform acts of kindness every day.

Digging deeper into the research, the team found that random acts of kindness, such as helping an older neighbour carry groceries, were more strongly associated with the overall well-being than formal prosocial behaviour, such as scheduled volunteering for a charity.

"That may be because informal helping is more casual and spontaneous and may more easily lead to forming social connections," Hui said. Younger givers reported higher levels of overall well-being, eudaimonic well-being, and psychological functioning, while older givers reported higher levels of physical health.

"Also, women showed stronger relationships between prosociality and several measures of well-being compared with men–perhaps because women are stereotypically expected to be more caring and giving," the authors wrote..