The potential of raw cow's milk to target allergic diseases: 'Well done, medium or rare?’

Allergic diseases are a growing public health concern. They affect the lives of more than a billion people worldwide and their prevalence is expected to rise to four billion by 2050. This vast increase is often explained by the loss of rural living conditions and associated changes in diet and lifestyle. The consumption of raw, unprocessed, cow’s milk is considered to be an important environmental exposure that can protect against allergic diseases. However, due to the possible contamination with pathogens, its consumption is discouraged by regulatory authorities. By using preclinical murine models, this thesis shows that raw cow’s milk consumption protects against key features of asthma and food allergy. The latter was confirmed in cow’s milk allergic children. The protective effect was associated with modulation of the T cell response and inhibition of the allergic effector response. Interestingly, the allergy-protective effect of raw cow’s milk was clearly destroyed by the currently used industrial milk processing techniques. The findings of this thesis furthermore show that heat-sensitive bioactive whey proteins in raw cow’s milk are responsible for the allergy-protective effect. Heating raw milk up to a maximum temperature of 60 °C or the use of milder processing methods, both with the purpose to retain these whey proteins, were demonstrated to be promising raw milk alternatives. The same applied to processed milk supplemented with bioactive whey proteins. In summary, this thesis shows that raw cow’s milk or its bioactive whey proteins could become part of new nutritional approaches for allergy management.