Instead of strengthening your bones, drinking more than three glasses of milk a day may increase the risk of early death, a study has found.
This could be due to the high levels of lactose and galactose (types of sugar) in milk, that have been shown to increase oxidative stress and chronic inflammation in animal studies, the researchers said.
Doctors and nutritionists have long recommended a diet rich in milk for boosting calcium intake and lowering risk of fracture.
“Our results may question the validity of recommendations to consume high amounts of milk to prevent fragility fractures,” said lead researher Karl MichaAlsson from Uppsala University in Sweden.
The researchers set out to examine whether high milk intake may increase oxidative stress, which, in turn, affects the risk of mortality and fracture.
Two large groups of 61,433 women (aged 39-74 years in 1987-1990) and 45,339 men (aged 45-79 years in 1997) in Sweden completed food frequency questionnaires for 96 common foods including milk, yoghurt and cheese.
Women were tracked for an average of 20 years, during which time 15,541 died and 17,252 had a fracture.
The researchers found no link between higher milk consumption and reduction in fracture risk in women.
Furthermore, women who drank more than three glasses of milk a day (average 680 ml) had a higher risk of death than women who drank less than one glass of milk a day (average 60 ml).
Men were tracked for an average of 11 years, during which time 10,112 died and 5,066 had a fracture.
Men also had a higher risk of death with higher milk consumption, although this was less pronounced than in women.
Further analysis showed a positive association between milk intake and biomarkers of oxidative stress and inflammation.
The study appeared in the British Medical Journal.