Milk was thought to be a valuable supplier for calcium and an effective means to strengthen bones and thus to prevent osteoporosis.
Karl Michaelsson, Uppsala University, Sweden and Swedish colleagues followed the health history of 61,433 Swedish women and 45,339 men (39 to 74 years and 45 to 79 years, respectively). Instead of a positive effect of milk on bone health, the researchers found a rather opposite effect: The women who drank three cups of milk or more per day had an even higher risk of breaking their hips than those who dank less than a glass milk per day. The death rate was increased in milk-drinking women and men. The frequent milk drinkers had higher biomarker for inflammation and oxidative stress in their blood. Participants who consumed little milk, but many fermented milk products like yogurt or cheese, did not show such an increase.
The lactose contained in milk is converted in the body to D-galactose – per glass of milk in about five milligrams of this sugar. Experiments show that mice, rats, and fruit flies that receive D-galactose age prematurely and die earlier. This is caused by increased oxidative stress and inflammation.
- Milk intake and risk of mortality and fractures in women and men: cohort studies
K. Michaelsson, A. Wolk, S. Langenskiold, S. Basu, E. Warensjo Lemming, H. Melhus, L. Byberg
BMJ 2014, 349, g6015–g6015.