Study suggests whole fat milk may reduce cardiovascular disease, but dietary advice will not change

A new study has suggested that whole fat dairy products such as milk and yogurt are linked to lower rates of cardiovascular disease however, the findings will not change current advice in relation to dairy and heart health.

The study, which was published recently in the Lancet, found that people who had three glasses of whole fat milk or yogurt a day, had lower rates cardiovascular disease, compared to those who consumed less than half a glass a day.

In the study of more than 130,000 people, one standard serving of dairy was equivalent to a glass of milk, a cup of yoghurt, one slice of cheese, or a teaspoon of butter.

For the study participants were grouped into four categories: those who had no dairy, those who had less than one serving a day, those that had 1-2 servings a day, and those who consumed more than two servings a day.

The findings revealed that compared to those who had no dairy, people who had more than two servings a day had lower rates of total mortality, non-cardiovascular mortality, cardiovascular mortality, major cardiovascular disease and stroke. There was no difference in the rates of myocardial infarction between the two groups.

Among those who consumed only whole-fat dairy, those who had an average of 2.9 servings a day had lower rates of total mortality and major cardiovascular disease compared to those who consumed less than 0.5 servings of whole-fat dairy a day, the study found.

According to the study, the findings are consistent with previous meta-analyses of observational studies and randomised trials but in contrast to current dietary guidelines which recommend consuming 2-4 servings of fat-free or low-fat dairy per day, and minimising consumption of whole-fat dairy products for cardiovascular disease prevention.

Cardiovascular disease is the leading cause of mortality worldwide. The authors concluded that the consumption of dairy should not be discouraged and should even perhaps be encouraged in low-income and middle-income countries where dairy consumption is low.

“Our findings support that consumption of dairy products might be beneficial for mortality and cardiovascular disease, especially in low-income and middle-income countries where dairy consumption is much lower than in North America or Europe,” said lead author Dr Mahshid Dehghan of McMaster University in Canada.

Commenting on the study Sarah Noone, dietitian with the Irish Heart Foundation said it was important to look beyond the headlines and not jump to conclusions about the findings of this one study.

“The results only suggest the consumption of dairy products should not be discouraged and perhaps encouraged in low-income and middle-income countries.”

According to Sarah, “Dairy products don’t need to be excluded from the diet to prevent heart disease and stroke. In this study the people with higher intakes were having about two to three portions of dairy a day, which is in line with current population level dietary advice in Ireland. We recommend that three servings of dairy per day are needed for good health for the general adult population which is based on the most up-to-date scientific research and is in line with the Department of Health’s Food Pyramid and Healthy Eating Guidelines.”

Sarah added that dairy provided protein as well as a range of important vitamins and minerals which are present in similar amounts in both whole and low-fat dairy products. The difference is that a low-fat dairy will be lower in calories, fat and saturated fat than whole dairy.

“There is considerable interest in whether some types of saturated fat – such as dairy fat– are less ‘unhealthy’ than others and whether or not all saturated fats have the same effect on heart health, but ultimately there is not enough evidence to justify population goals for individual types of fat.”

Sarah said it was important to stress that nutritional science was evolving, with new discoveries being made all the time, however population recommendations are made on the entirety of the best evidence available, not one single study.

“Therefore, our advice is clear, reduce and replace saturated fats with unsaturated fats where possible and avoid trans fats. Diets high in saturated fat is associated with raised levels of LDL (bad) cholesterol. This is linked to an increased risk of heart disease. That’s why official recommendations emphasise the importance of reducing saturated fat in our diets,” she explained.

Sarah added that this study did not explain why a higher dairy intake appeared to be linked to lower risk of death and cardiovascular disease, as it only looked at associations, not cause and effect. Therefore, the findings are not a seal of approval for changing population guidelines and recommending whole-fat dairy over reduced or low-fat alternatives, she said.

“It’s easy to forget that we need to consider our whole diet and dietary pattern to reduce our overall risk of heart disease and stroke. There are many factors which cause heart disease and stroke and no single food or nutrient is solely responsible for this. What matters most is the bigger picture of how balanced our diets are overall and having a healthy relationship with food – not whether we include one specific food in our diet or not.”