Bovine milk in human nutrition – a review

Anna Haug¹ , Arne T Høstmark² and Odd M Harstad¹

Abstract

Milk and milk products are nutritious food items containing numerous essential nutrients, but in the western societies the consumption of milk has decreased partly due to claimed negative health effects. The content of oleic acid, conjugated linoleic acid, omega-3 fatty acids, short- and medium chain fatty acids, vitamins, minerals and bioactive compounds may promote positive health effects. Full-fat milk has been shown to increase the mean gastric emptying time compared to half-skimmed milk, thereby increasing the gastrointestinal transit time. Also the low pH in fermented milk may delay the gastric emptying. Hence, it may be suggested that ingesting full-fat milk or fermented milk might be favourable for glycaemic (and appetite?) regulation. For some persons milk proteins, fat and milk sugar may be of health concern. The interaction between carbohydrates (both natural milk sugar and added sugar) and protein in milk exposed to heat may give products, whose effects on health should be further studied, and the increasing use of sweetened milk products should be questioned. The concentration in milk of several nutrients can be manipulated through feeding regimes. There is no evidence that moderate intake of milk fat gives increased risk of diseases.

Introduction

Bovine milk and dairy products have long traditions in human nutrition. The significance of milk is reflected in our northern mythology where a cow named Audhumla was evolved from the melting ice. She had horn and milk was running as rivers from her teats. This milk was the food for Ymer, the first creature ever existing [1].

The consumption of milk and milk products vary considerably among regions; of drinking milk from about 180 kg yearly per capita in Island and Finland to less than 50 kg in Japan and China [2]. In the western societies, the consumption of milk has decreased during the last decades [3]. This trend may partly be explained by the claimed negative health effects that have been attributed to milk and milk products. This criticism has arisen especially because milk fat contains a high fraction of saturated fatty acids assumed to contribute to heart diseases, weight gain and obesity [4].

The association between food and health is well established [4] and recent studies have shown that modifiable risk factors seem to be of greater significance for health than previously anticipated [5]. Prevention of disease may in the future be just as important as treatment of diseases. Indeed, many consumers of today are highly aware of health-properties of food, and the market for healthy food and food with special health benefits is increasing.

Milk is a complex food made up of components, which per se may have negative or positive health effects, respectively. Milk composition can be altered by the feeding regime. The main aim of this review is to discuss effects of milk components that are of particular interest for human health, and to give an overview of the potential for manipulation of bovine milk by feeding regimes to the lactating cows, thus giving improved nutritional composition of the milk for human consumption.