Consumption of dairy products?particularly milk?has always been pushed as the best way to ensure bone health and delay the process of osteoporosis. Though this mainstream belief persists, more and more evidence suggests drinking milk may not be as good for us as we originally thought, not even when it comes to bone health.
In fact, a recent study from Sweden, led by Prof. Karl Michaëlsson, disputes the common belief that milk benefits bone health. According to this latest data, milk may actually increase oxidative stress, subsequently increasing an individual’s risk of mortality and bone fracture.
After evaluating the health and dietary habits of more than 100,000 people, Michaëlsson and his team found, overall, consumption of milk was not associated with any reduction in fracture rate; in both men and women, the beverage was actually linked to a higher rate of fractures.
Both men and women who drank milk were also more likely than individuals who did not drink milk to die at a younger age.
“As milk features in many dietary guidelines and both hip fractures and cardiovascular disease are relatively common among older people, improving the evidence base for dietary recommendations could have substantial benefits for everyone,” wrote Prof. Mary Schooling, at City University of New York, in an editorial accompanying the research. “As milk consumption may rise globally with economic development and increasing consumption of animal source foods, the role of milk in mortality needs to be established definitively now.”
This is not the first time milk has been linked to an increase in bone fractures. According to Save Our Bones, a 12-year Harvard Nurses Health Study found that those who consumed the most calcium from dairy foods broke more bones than those who rarely drank milk (Source: Feskanich D, Willett WC, Stampfer MJ, Colditz GA. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study., of
American Journal of Public Health. 1997). Also, the Case-Control Study of Risk Factors for Hip Fractures in the Elderly,” published in the American Journal of Epidemiology. Vol. 139, No. 5, 1994, found consumption of dairy products, particularly at age 20 years, was associated with an increased risk of hip fracture in old age.
How could milk actually be bad for bone health?
Though the research is on-going, there are two primary theories about why milk is actually associated with poor bone health. The first theory is that milk, as an animal protein, acidified the body pH and then prompts a reaction from the body to neutralize it. This acid neutralization comes from calcium, and the body pulls calcium from the bones when it doesn’t have enough at its disposal.
Another theory as to why milk could be bad for bone health has to do with D-galactose, galactose making up half of lactose, the sugar found in milk. Previous studies have linked galactose to oxidative stress damage, chronic inflammation, neurodegeneration, decreased immune response and gene transcriptional changes.
Combined, these two theories could spell disaster for bone health in people who drink milk, even though some calcium and vitamin D are being consumed through the product.
In addition to bone health issues, materials from Harvard University state milk consumption in humans has been linked to ovarian cancer and prostate cancer risk.