Milk is heavily promoted by the Dairy industry as a source of Calcium and being good for bones but a new paper published in the British Medical Journal has found that higher intake of milk in women is not associated with a reduced fracture risk and may also be linked to increased risk of early death. As with all medical studies though, caution is needed in making changes on the basis of this new information.
The original study was carried out in Sweden - A questionnaire asking about diet was sent out with mammogram appointments and over three quarters of the women completed the survey. 70% of these women were followed up for 10 years and their rates of fractures and deaths were monitored.
It was found that despite the higher calcium intake, drinking 3 glasses of milk a day was associated with a very small increase in the risk of hip fracture compared with lesser amounts of milk consumption.
For heart disease, 3 glasses per day was associated with a 1.5 times increase in the risk of heart disease and 6 glasses per day with a 3 times higher risk of heart disease. This was not seen with yoghurt or cheese however.
There are a lot of reasons why this might be the case, not least the fact that women with lower bone density may have been drinking more milk in an attempt to reduce this. Similarly, people who are more unwell often see milk as a healthy food so this might explain the small increase in heart disease risk.
It is also possible that one of the sugars in milk (galactose - about 5% in cow's milk) might be the cause of the problem, especially as this is found in smaller quantities in yoghurt (it is consumed by the bacteria) and in cheese. Galactose is known to increase oxidative stress and there is some evidence that heart disease is associated with greater oxidateive stress.
In 2011 a large meta-analysis of milk consumption concluded that milk seemed to offer no benefit in preventing hip fractures and a US meta-analysis showed no significant cardiovascular disease risk increase with milk consumption so the picture is of course confused. It seems likely that more milk will not help you avoid fractures, but neither is it really that significantly associated with heart disease either.
Overall our advice based on the findings today is to be aware that there is little or no evidence to support either consuming more milk (3+ AOK campaign) or avoiding it for health. Children probably benefit from milk and dairy product consumption but for adults they are less beneficial. Individual circumstances really need to be taken into consideration too, so please discuss any concerns you might have with your doctor before considering any changes.
If we were advising people today, our advice would be much the same as it always has been - For children dairy products are probably helpful but as you age the need reduces and dairy should form only a small part of the adult diet. This is consistent with most internationally recognised nutritional advice.