High milk consumption may not cut risk of bone fractures

Milk is rich in calcium; a key component of bones may increase risk of fractures by over consumption.

A study in the British Medical Journal suggests, drinking lots of milk may not lower the risk of fracturing bones

The research, conducted in Sweden, found that women who drank more than three glasses of milk a day were actually more likely to break bones than those who had less consumption of milk.

The researchers cautioned that their work only suggested a trend and should not be interpreted as proof that high milk consumption caused fractures.

Factors such as alcohol and weight were likely to play a role, they said.

Twice the chance

Milk has been recommended as a good source of calcium for many years, but studies that looked into the link between milk and fewer fractures had conflicting results.

A team of scientists in Sweden examined the dietary habits of 61,400 women in 1987 -1990 and 45,300 men in 1997 and then monitored their general health for years afterwards.

Participants were asked to complete questionnaires on how frequently they consumed common foods such as milk, yoghurt and cheese over a one-year period.

Participants were asked about how frequently they consumed common foods such as milk, yoghurt, and cheese over a year period.

In the 20-year follow-up period, the women were monitored; those who drank more than three glasses, or 680ml, of milk a day were more likely to develop fractures than those who had consumed less milk.

The high-intake group had a higher risk of death too.

“Women who drank three or more glasses a day had twice the chance of dying at the end of the study than those who drank less than one glass a day,” said Prof Karl Michaelsson, lead researcher at Uppsala University.

“And those who had a high milk intake also had a 50% higher risk of hip fracture.”

The men surveyed showed a similar, but less pronounced, trend, 11 years after the initial survey.

Opposite pattern

When fermented milk products such as yoghurt were considered, the opposite pattern was observed – people who consumed more had a lower risk of fractures.

Prof Michaelsson says the findings could be due to sugars in milk, which have been shown to accelerate ageing in some early animal studies.

“Our results may question the validity of recommendations to consume high amounts of milk to prevent fragility fractures.”

“The results should, however, be interpreted cautiously given the observational design of our study.”

He also said “Dietary advice should not be changed until more research had been conducted.”

The study was of limited use. “We do not have a feel for the influence of physical activity or other lifestyle habits important to bone or overall mortality,” said by Prof Sue Lanham-New, from the University of Surrey.

“And the effect of increasing body mass index has not been fully investigated in this study.”

“Milk and dairy products in the UK provide 50-60% of the calcium in our diet.”

“We know that low calcium intake (less than 400mg a day) is a risk factor for osteoporosis.”

“Individuals should still be encouraged to consume a balanced diet from the five key food groups of which milk and dairy are key.”