Caution urged over Swedish milk study

A diet rich in milk is promoted to reduce the likelihood of bone fractures but a high intake may have undesirable effects, according to new research.

Experimental evidence in several animal species indicates that chronic exposure to D-galactose is deleterious to health.

The research comprised an analysis of two large Swedish cohort studies, in which a group of men and a group of women were given food questionnaires and then followed up for an average of 20 years. Researchers looked at whether how much milk they drank was linked to fractures or death during follow-up.

In women, drinking any more than 200g of milk daily (less than one glass) was linked to increased risk of dying during follow-up. This increased risk ranged from 21% for one to two glasses to an increased risk of 93% for three or more.

More than one glass a day was also linked to an increased risk of fractures in women. There wasn't such a clear link with either early death or fractures in men.

However, people involved in the study may not have been able to reliably estimate their volume of milk intake per day, and there may have been various unmeasured factors influencing the outcomes.

This was also a Swedish population, who may have distinct health and lifestyle factors or environmental influences, which means the results are not applicable to other populations.

For example, milk in Sweden is fortified with vitamin A (unlike the UK), and high levels of vitamin A intake have been linked to an increased risk of fracture.

These findings are undoubtedly worthy of further research, but people should not feel the need to drink less milk based on this study alone.

“Scientists, including the authors of this research, vehemently warn that observational studies such as this showed be viewed with caution," said Dr Anne Mullen, Director of The Dairy Council.

"On one hand the study suggests an association between milk consumption and mortality and fracture, yet an opposite trend with cheese and fermented milk consumption. Many other studies contradict the findings of this study with regard to milk. A similar study from Japan, published just this month, showed that drinking milk was associated with lower all-cause mortality in men and women. The nutritional benefits of milk and dairy products, including a range of vitamins and calcium, and potassium are well documented.”