How does fermented dairy, in particular, affect heart health?
Coronary heart disease (CHD) is a condition in which the blood supply to the heart becomes restricted, usually because of a buildup of fat in the arteries that carry blood to the heart muscle.
There is still a lack of consensus on whether consuming dairy is good or bad for a person's health. However, it is important to distinguish between different types of dairy, which may vary in their effects on long-term physical health.
The results of a new study by researchers from the University of Eastern Finland, which has campuses in Joensuu, Kuopio, and Savonlinna, suggest that consuming fermented dairy products may actually protect the heart. Such products include cheese, kefir, yogurt, quark, and sour milk.
The team's findings, which appear in the British Journal of Nutrition, indicate that men who consume fermented dairy have a lower risk of incident CHD than men who prefer non-fermented dairy products.
Fermented dairy linked to lower risk
This research was part of the ongoing Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study. In their current project, the scientists studied associations between incident CHD and the consumption of different types of dairy product.
The team analyzed the data of 1,981 men aged 42–60 years who joined the KIHD study in the years 1984–1989. None of the participants had CHD at baseline, and they all provided details on their dietary habits when they joined the project.
Over an average follow-up period of 20 years, the participants reported 472 cardiovascular events relating to incident CHD.
To determine how the consumption of dairy products might influence the participants' risk of CHD, the researchers divided them into different groups depending on their dietary intake of various fermented and non-fermented dairy foods.
Among the men who consumed fermented dairy products with less than 3.5 percent fat content, those in the highest consumption group had a 27 percent lower risk of CHD compared with those in the lowest consumption category.
The researchers also observed that the most widely consumed low-fat fermented dairy product was sour milk, and that eating high-fat fermented dairy foods, such as cheese, did not appear to sway CHD risk one way or the other.
Milk tied to higher risk of CHD
At the same time, the team found that people who consumed a lot of non-fermented dairy products, of which regular milk had the greatest use, had a higher risk of incident CHD.
More specifically, those who had a very high intake — referring to an average of 0.9 liters of milk per day — were the most vulnerable to heart disease.
However, there was no association between low consumption of non-fermented dairy products and a heightened risk of CHD.
"Here in Finland, people's habits of consuming different dairy products have changed over the past decades," notes study co-author Jyrki Virtanen, adding:
"For instance, the consumption of milk and sour milk have declined, while many fermented dairy products, such as yogurt, quark, and cheeses, have gained in popularity."
Although the researchers cannot yet confirm the underlying mechanisms that are possibly at play in these associations, they speculate that certain compounds that form during the fermentation of milk-derived products may have a protective cardiovascular effect.