A healthy diet and lifestyle play an important role in preventing many chronic diseases and maintaining cardiovascular health. For a healthy lifestyle it is important not to smoke, to maintain a healthy weight and to eat according to national guidelines with sufficient fruit and vegetables, fish, fiber and not too much saturated fat. To limit the intake of saturated fat, nutrition authorities advise to choose skimmed or semi-skimmed dairy products. However, in the scientific literature, studies can be found which show that dairy fat intake may reduce risk factors for cardiovascular diseases.
FrieslandCampina Institute spoke to Ilse Pranger about her PhD research at the University of Groningen, in the Netherlands. During this PhD research she examined whether certain fatty acids, measured in blood, can serve as a biomarker for the consumption of dairy fat (meaning that these fatty acids reflect the intake of fat from dairy). In addition, she examined the association between biomarkers for dairy fat intake and risk factors for cardiovascular diseases.
‘Many studies measure the intake of dairy by means of food frequency questionnaires or nutrition diaries. These are good research techniques, however they can sometimes be inaccurate (e.g. people fill in desirable answers or forget certain foods). Therefore, we started looking for a different method to be able to measure dairy intake in a more objective way.
In our research, we have identified a number of saturated and trans fatty acids as biomarkers for the consumption of dairy fat. When these biomarkers are combined, they best predict the intake of dairy fat (and therefore the intake of dairy), however the correlation is not very strong. Therefore it is advised to always combine the biomarkers with a questionnaire, to see if this gives a consistent picture.
We also looked at the association between the biomarkers and the intake of different dairy products, such as skimmed, semi-skimmed and full fat dairy products, yoghurt and cheese (butter was not included). This showed that the biomarkers were most closely related to the consumption of cheese and full-fat dairy products.’
Risk factors for cardiovascular diseases
‘In general, we found a favorable association between the biomarkers and certain risk factors for cardiovascular diseases, such as weight, cholesterol and blood glucose. This shows that the consumption of dairy possibly has a favorable effect on cardiovascular health.
One of the fatty acids that was identified as a biomarker for dairy fat intake, a certain trans fatty acid, has two different variants: a natural one that is present in dairy and an industrially produced variant.
We examined whether it was true that the first variant is related to dairy intake and the second variant was not: that was indeed correct. Additionally, we examined the association between these trans fatty acids and risk factors for cardiovascular diseases. Our research showed that the natural trans fatty acid present in dairy has a favorable effect on cardiovascular health. We did not find this association with the industrial trans fatty acid.’
Follow up studies
‘Other studies that looked at the association between the consumption of dairy fat and cardiovascular risk factors show varying results. Especially studies that work with questionnaires often show a neutral, instead of positive association between dairy fat consumption and certain health outcomes. Therefore, more research is needed to confirm that consumption of dairy fat has a positive effect on cardiovascular health.
As follow-up to this PhD research, it would be interesting to look at the health effect of the consumption of dairy fat in the longer term. In the current study we have only looked at the association between the biomarkers and risk factors for cardiovascular disease at one point in time.’
Ilse Pranger (1988) studied Nutrition and Health at the Wageningen University. During her PhD research she was affiliated with the GUIDE research institute of the University Medical Center Groningen. She is currently working as a Clinical Research Associate at PPD. The title of her dissertation is: “Fatty acids as biomarkers for health status and nutritional intake – focus on dairy and fish”.