Basing their findings on data collated from presentations, discussions and conclusions drawn from a workshop on the dairy matrix, the researcher argue the nature of the food structure and its nutrients determine the nutrient digestion and absorption, "thereby altering the overall nutritional properties of the food,” write the authors.
“Thus, the food matrix may exhibit a different relation with health indicators compared to single nutrients studied in isolation.”
They conclude the nutritional values of dairy products should be considered on the basis of the biofunctionality of the nutrients within dairy food structures.
Good and bad
Fermented dairy products, such as cheese and yoghurt, generally show inverse associations with cardiovascular disease, such as stroke and coronary heart disease.
They are also more beneficial for bone health and maintaining body weight (thanks to the probiotic cultures that have a positive impact on insulin sensitivity) than would be expected on the basis of their saturated fat and calcium content.
They also draw examples from almonds. "[Almonds] contain a lot of fat, but [they] release less fat than expected during digestion, even when chewed really well,” said Tanja Kongerslev Thorning from the department of nutrition, exercise and sports at the University of Copenhagen and first author of the report.
“The effects on health of a food item are probably a combination of the relationship between its nutrients, and also of the methods used in its preparation or production. This means that some foods may be better for us, or less healthy, than is currently believed."
The authors have called for more research on the subject.
Professor of food chain nutrition Ian Givens at the University of Reading said: "More studies are needed, but ultimately it seems that some areas of nutrition science need to be rethought. We cannot focus on a nutrient without looking at how it is consumed and what else is eaten at the same time."
The authors of the study, published in the American Journal of Clinical Nutrition, are not the first to suggest that the single nutrient model, which has been used by governments around the world to develop national eating guidelines, is severely limited.
Professors at the University of Sydney's Charles Perkins Centre, David Raubenheimer and Stephen Simpson, last year developed a framework they called ‘nutritional geometry’ in the battle against obesity, which looks at how mixtures of nutrients and other dietary components influence health and disease, rather than focusing on a single nutrient in isolation.
Some countries are already doing so. France’s nutrition logo calculates a score for each food or drink product’s entire nutrient profile and assigns a single colour based on this. The UK’s traffic light label is based on the single-nutrient model, meaning a product such as cheese could receive red for salt and fat but green for sugar.
Source: American Journal of Clinical Nutrition
“Whole dairy matrix or single nutrients in assessment of health effects: current evidence and knowledge gaps”
First published ahead of print April 12, 2017 as doi: 10.3945/ajcn.116.151548
Authors: Tanja Kongerslev Thorning, Hanne Christine Bertram, Jean-Philippe Bonjour et al