Milk: It does a body good ... or does it? Though they say their findings should be interpreted cautiously, Swedish researchers have identified a correlation between heavier milk consumption and a higher mortality rate among women. Karl Michaelsson and his team tracked 61,433 women for an average of 20 years; they ranged in age from 39 to 74 at the start of the study. In looking at women who drank an average of 2.9 cups of milk a day compared to those who drank less than one (an average of about 2 ounces), researchers discovered there was no reduction in fracture risk—but the heavier milk-drinking group was 1.93 times more likely to die during the study, reports LiveScience. (The study, published in the British Medical Journal, also tracked a group of men; a much less significant increase in mortality risk was identified among those with a higher intake.)
Michaelsson thinks a milk sugar called galactose may play a role. He suspects it can trigger oxidative stress and inflammation: "The funny thing is that if you provide galactose to experimental animals, they will die faster" due to those two things, he says. A press release explains the team's analysis uncovered a positive relation between milk intake and a biomarker of oxidative stress. However, consumption of fermented milk products (like yogurt) affected the biomarker oppositely. "Our results may question the validity of recommendations to consume high amounts of milk to prevent fragility fractures," they write, while noting the findings shouldn't yet be used to shape dietary recommendations. But Michaelsson, for his part, hasn't drunk milk in two years.