The study, published in The Journal Nutrition, Metabolism and Cardiovascular Diseases, suggested dairy intake did not vary significantly between people who had and had not suffered from heart attacks.
The adverse effect of saturated fat on cardiovascular health could be cancelled out by nutrients found in dairy products which are protective against heart disease, said the Brown University researchers.
This could be the case for all but possibly the highest dairy consumption group in the study, they said.
Such nutrients include calcium, vitamin D, potassium, magnesium and conjugated linoleic acid (CLA).
Methodology and results
The researchers analysed data on 3,630 middle-aged Costa Rican men and women who participated in an epidemiological study between 1994 and 2004.
The participants were split into two equal groups, those who had non-fatal heart attacks and a control group of those who had not.
The scientists looked at the subjects’ self-reported dairy intake and measurements of dairy fat biomarkers, controlling for risk factors such as smoking, waist-to-hip ratio, alcohol intake, and physical activity.
Dairy intake was defined to include intake of butter, buttermilk, cheeses (including mozzarella-style cheese, cottage cheese, and cream cheese), cream, ice cream, lactocrema (a mixture of butter and margarine), milk (whole, 1 per cent, and 2per cent), and yoghurt.
After separating participants into quintiles, based on their level of dairy consumption, the researches said they found no significant linear relationship between consumption and heart risk.
This applied even to participants with the highest intake. The highest quintile group consumed an average of 593 grams of dairy foods a day.
The researchers also tracked and adjusted the data for levels of CLA and calcium and found they may have a protective effect, although protective effects lessened in the highest quintile.
In the study’s discussion, the researchers point out that the association between dairy intake and cardiovascular health is likely to emerge from a balance of protective and risk factors.
To conclude, they said the mechanisms underlying the association are complex and warrant more research.
Source: Nutrition, Metabolism & Cardiovascular Diseases (2011)
“Biomarkers of dairy intake and the risk of heart disease”
Authors: Aslibekyan S, et al