Milk Associated with Increased Risk of Death, Study Says
A study of 106,772 Swedish adults has found a correlation between milk consumption and an increased risk of dying. The study also found milk to be associated with higher rates of bone fractures in women, and found no evidence that milk provided protection against fractures in men.
Women who drank two glasses of milk per day had a 21% greater risk of dying during the 22-year study period than women who drank one glass per day. Women who drank three glasses or more had a 93% greater risk of dying during the study period. The women who died during the study were predominantly victims of cardiovascular disease and cancer. In men, the risk of dying rose only slightly with increased milk intake, mostly related to incidents of heart disease. Women who drank two glasses of milk a day were 16% more likely to suffer a fracture, with no elevated risk of fracture in men. The study did not specify whether whole, low-fat, or fat-free milk was consumed.
The study, led by Karl Michaelsson, MD, PhD, a professor of medical epidemiology at Uppsala University, Sweden, and published in the peer-reviewed journal BMJ (formerly known as the British Medical Journal), followed 61,433 women aged 39-74 and 45,339 men aged 45-79. The subjects were asked to complete questionnaires on their food consumption. Michaelsson said he has been studying fracture rates for 25 years, and was “puzzled… because there has again and again been a tendency of a higher risk of fracture with a higher intake of milk.”
The consumption of cheese and fermented milk products such as yogurt were not associated with increased fractures and mortality rates, and in fact women with high intakes of those products had lower fracture and mortality rates. Hip fractures and mortality rates in women were reduced by 10-15% for each serving of cheese or fermented milk products.
Michaelsson and his team suggested that a reason for milk’s association with fractures and increased death rates may be the high content of D-galactose (a sugar) in milk. In contrast, fermented milk products and cheese have a substantially lower D-galactose content. However, the authors caution that controlled experiments, rather than an observational study such as this one, would be required to demonstrate causality.
Other researchers have advised not to read too much into the study’s findings. Luisa Dillner, MD, head of BMJ Group Research and Development, noted that the study drew its data from people’s recollections of their eating and drinking habits, “which isn’t always reliable.” Angela M. Zivkovic PhD, Assistant Professor of Nutrition at the University of California at Davis, also questioned the self-reported findings, adding that she is yet to be convinced by this and previous milk studies showing detrimental health effects: “I think [milk is]… a positive part of a healthy diet. I haven’t seen any convincing evidence that there’s something about dairy that’s unhealthful.” Zivkovic’s own research has been funded by pro-dairy groups.
The US Department of Agriculture (USDA) currently recommends that all people nine years and older consume three cups of dairy products per day.
British Broadcasting Corporation (BBC), “Study Casts Doubt on Health Benefits of Milk,” bbc.com, Nov. 18, 2014
Aaron E. Carroll, “Got Milk? Might Not Be Doing You Much Good,” nytimes.com, Nov. 17, 2014
Luisa Dillner, “Should We Be Worried about Drinking Milk?,” theguardian.com, Nov. 16, 2014
Karl Michaëlsson et al., “Milk Intake and Risk of Mortality and Fractures in Women and Men: Cohort Studies,” bmj.com, Oct. 28, 2014
Rebecca Plevin, “Help! Should I Still Drink Milk,” scpr.org, Nov. 24, 2014
C. Mary Schooling, “Milk and Mortality,” bmj.com, Oct. 28, 2014
United States Department of Agriculture, “How Much Food from the Dairy Group Is Needed Daily?,” choosemyplate.gov (accessed Nov. 25, 2014)
Justin Worland, “Milk Might Not Save Your Bones, Study Says,” time.com, Oct. 29, 2014