This old saying has been supported by two new studies: Laughter can reduce the harm caused by type 2 diabetes and can improve the quality of milk in breastfeeding mothers.
Diabetes: In Japan, sixteen healthy persons and twenty-three patients with type 2 diabetes have watched a comedy show. Before and after the show, blood levels of a substance (prorenin) that has an adverse effect on the kidneys have been measured. In diabetic patients, the level of prorenin is higher than in healthy persons. After the show, the level was clearly lower in the patients. Thus, laughter helps to protect the kidneys against the harm caused by diabetes.
Breastfeeding: In another Japanese study, fourty-eight mothers of babies suffering from allergic eczema either have watched the Charlie Chaplin movie «Modern Times» or a weather information show. After the film, breast milk of the mothers has been collected and analyzed. In the milk of mothers who had watched the Chaplin movie a lot more of melatonin has been found; no such change happened with the weather show. Melatonin is a natural sleep hormone that has a soothing effect on babies. And even better: When the babies have been fed with humour-improved milk, they suffered less from allergies.
Wikipedia: Laughter, Laughter Yoga
(Picture by rebecca anne @ Plickr)