Study methodology 

“The strengths of the study are the large number of participants, the repeatedly recorded dietary habits and other information over long follow-up periods and the wide range of consumption habits with regard to dairy products. Many established risk factors for cardiovascular disease were also taken into account in the analyses. However, it is striking that people with a very high consumption of non-fermented dairy products tended to have ‘unhealthy’ characteristics, such as a lower level of education or a higher proportion of current smokers. Although the authors controlled for these confounders, residual confounding cannot ultimately be ruled out in observational studies.” 

Classification of the results 

“The increase in risk of high milk consumption only affected women in the study, but not men. This was apparently only noticeable from consumption quantities of over 300 millilitres per day. The higher the consumption volume, the higher the risk: compared to women who drink 100 millilitres of milk per day, women who consumed 400 millilitres had a 5 per cent higher risk, and with 800 millilitres (four glasses) a 21 per cent higher risk. It can therefore not be ruled out that very high milk consumption increases the risk of heart disease in women.” 

Implications of the study data for dietary recommendations 

“Since the risk increase was only observed with very high consumption levels, which are more common in Scandinavia than elsewhere, the results probably do not affect most female consumers in other European countries.” 

Dairy products are a fundamental source of proteins of high biological value, calcium and other minerals, vitamins A, D B6 and B2, and saturated fats. In addition, non-fermented dairy products contain lactose, a sugar that causes digestive problems in people with lactose intolerance.

The scientific literature that has examined the association between dairy consumption and the risk of developing cardiovascular disease is extensive. Two recent meta-analyses of observational studies concluded that dairy consumption was associated with a lower risk of hypertension, diabetes, coronary heart disease and stroke. In particular, consumption of fermented dairy products had a more beneficial effect.

The study just published comes to conclusions contrary to previous evidence. In two different populations of people living in Sweden, dairy consumption was measured during 30 years of follow-up. It was observed that women who consumed higher amounts of dairy (300 mL/day or 1.5 glasses/day) had a higher risk of developing coronary heart disease, compared to people with low intakes (less than 1 glass/day). This association was not found in men, nor was it found for the consumption of fermented dairy products, mainly yogurt. In addition, they identify some blood proteins that seem to mediate the biological mechanisms involved in the association found.

Although these results could be attributed to the amount of saturated fat ingested with dairy products, since the consumption of three products per day can contribute an amount of saturated fat in the diet above the recommended amount, the results were similar when the effect of whole, semi-skimmed and skimmed dairy products were examined separately.

One possible explanation for these results may be that the high consumption of dairy in this Scandinavian country makes it possible to observe detrimental effects that have not been possible to observe in countries with lower intakes. Therefore, rather than focusing on these results, it is advisable to adhere to the current dietary recommendations for the Spanish population, published by the Spanish Agency for Food Safety and Nutrition, which suggest a consumption of up to three dairy products per day, fermented if there is lactose intolerance, as a source of protein and calcium, avoiding those with added sugars and high salt content.