A new study has demonstrated that high milk intake in women and men may have an adverse impact, linked to a higher risk of fractures and death. Milk has been touted as a preventative mechanism to prevent bone fractures.
The adverse health impact was attributed to high levels of lactose and galactose in milk which acts to increase oxidative stress and chronic inflammation in animal studies.
The research participants consisted of two large groups of 61,433 women (aged 39-74 years in 1987-1990) and 45,339 men (aged 45-79 years in 1997) in Sweden who completed food frequency questionnaires for 96 common foods including milk, yogurt and cheese.
The study tracked lifestyle information. National registers were used to track fracture and mortality rates.
The women were tracked for an average of 20 years, during which time 15,541 died and 17,252 had a fracture, of whom 4,259 had a hip fracture. In women, no reduction in fracture risk with higher milk consumption was observed. Furthermore, women who drank more than three glasses of milk a day (average 680 ml) had a higher risk of death than women who drank less than one glass of milk a day (average 60 ml).
Men were tracked for an average of 11 years, during which time 10,112 died and 5,066 had a fracture, with 1,166 hip fracture cases. Men also had a higher risk of death with higher milk consumption, although this was less pronounced than in women.
In direct contrast, a high intake of fermented milk products with a low lactose content (including yoghurt and cheese) was associated with reduced rates of mortality and fracture, particularly in women.
The researchers concluded that a higher consumption of milk in women and men is not accompanied by a lower risk of fracture and instead may be associated with a higher rate of death. They suggest that further analysis is needed.
K. Michaelsson, A. Wolk, S. Langenskiold, S. Basu, E. Warensjo Lemming, H. Melhus, L. Byberg. Milk intake and risk of mortality and fractures in women and men: cohort studies. BMJ, 2014; 349 (oct27 1): g6015 DOI: 10.1136/bmj.g6015
C. M. Schooling. Milk and mortality. BMJ, 2014; 349 (oct27 1): g6205 DOI: 10.1136/bmj.g6205