High Milk Intake does not Lower Risk of Fractures and Mortality
Milk for adults is not linked to a lower risk of fracture, a new study found. Instead, the researchers reported that drinking too much milk can lead to an increased risk of death.
"Our results may question the validity of recommendations to consume high amounts of milk to prevent fragility fractures," the authors wrote according to the press release. "The results should, however, be interpreted cautiously given the observational design of our study. The findings merit independent replication before they can be used for dietary recommendations."
For this study, the Swedish researchers headed by Professor Karl Michaëlsson examined two large groups of adults. The first group consisted of 61,433 women between the ages of 39 and 74 and the second group included 45,339 men, aged 45 to 79. The participants completed food questionnaires regarding 96 foods. The researchers collected information on the participants' lifestyle habits, educational level, marital status, height and weight. Data on fracture history and mortality rates were taken from national registers.
Over an average of 20 years, 15,541 women died. 17,252 suffered a fracture with 4,259 of them being hip fractures. Milk consumption was not linked to fracture risk. However, women who drank more than three glasses per day had a greater risk of death when compared to those who drank less than one glass.
For men, over the span of 11 years, 10,112 died. 5,066 had a fracture with 1,166 of them being hip fractures. Similarly to women, men who drank more milk also had an increased risk of death. The relationship between high milk intake and mortality rate was less pronounced in men.
The team reasoned that milk could contribute to a greater risk of death because it contains high levels of lactose and a type of sugar known as galactose. Both compounds have been linked to increasing oxidative stress as well as chronic inflammation in animal studies. When the researchers analyzed this relationship, they found a link between milk and biomarkers of oxidative stress and inflammation.
"As milk consumption may rise globally with economic development and increasing consumption of animal source foods, the role of milk and mortality needs to be established definitively now," Professor Mary Schooling at City University of New York wrote in an accompanying editorial.
The study was published in The BMJ.