The role of dairy proteins in diseases such as Alzheimer’s, Parkinson’s and Huntington’s diseases is being investigated as scientific studies show they may play a protective role. Alzheimer’s disease is a progressive condition caused by the deposition of plaques in the central nervous system. These plaques are a result of protein misfolding. Recent research has shown that milk’s casein proteins, in particular ?s-casein and ?-casein, can interact with and stabilise other proteins and in doing so prevent protein aggregation.
Current research into the possible protective role of dairy peptides in such diseases is relatively new, but findings are promising. A study in the Australian Journal of Dairy Technology by Bennett et al (2009) has demonstrated that two hydrolysates of whey protein exhibited superior anti-fibril bioactivity against specific peptides associated with fibrillar plaque deposits in brains of Alzheimer’s disease patients, thereby demonstrating the capacity of dairy protein peptides to be beneficial.
Milk proteins and peptides are coming under increasing interest, and with the incidence of type-2 diabetes on the increase, dairy peptides may be effective in blood glucose management. Consuming protein doesn’t raise plasma glucose level, rather it may increase the level of insulin. Preliminary data shows a protein hydrolysate (InsuVital, DSM Food Specialties) given to type-2 diabetes patients, and healthy subjects can beneficially modulate glucose levels after eating and increase insulin secretion and also improves glucose disposal in diabetic subjects.
The blood pressure lowering effect of bioactive milk peptides (breakdown product of protein) has been reported in many studies, but milk peptides may also play a more extensive role in cardiovascular health beyond their impact on blood pressure. Milk products containing the milk peptides IPP (isoleucine-proline-proline) and VPP (valine-proline-proline) can significantly improve the ambulatory arterial stiffness index, which is an independent risk factor for cardiovascular disease, as well as improving endothelial dysfunction, as reported in clinical studies.
Milk is often portrayed as a natural sports drink and has been shown to be more effective than water and commercially produced sports drinks at rehydrating the body after exercise. Milk and its components offer numerous benefits to sports people, ranging from hydration to helping to improve muscle strength, to improving exercise capacity and performance. A study carried out in male cyclists, published in February 2009, showed that chocolate milk is a more effective recovery aid after prolonged endurance exercise than a carbohydrate replacement drink or fluid replacement drink. The type of carbohydrate and/or fat content may be responsible for the reported difference.
Dairy proteins have long been used to provide additional protein for sports people to help facilitate increased muscle mass and improve sports performance. New protein isolates encrypted within milk proteins and liberated following hydrolysis are now being isolated, developed and commercialised in powders, bars and beverages tailored to maximise athletic performance of elite athletes.
Other milk and dairy components are being incorporated into various health-related products. Whey permeate-derived ingredients such as galacto-oligosaccharides (GOS) and lactiobionic acid are clear examples of ‘waste’ products finding a role in health and nutrition. GOS are non-digestible prebiotics that promote a healthy colonic microflora in humans.
Additional reported health benefits show it to have an anti-caries effect as well as a beneficial role in bowel cancer and constipation. Lactobionic acid obtained from the oxidation of lactose, which is found only in milk, is used for the cold storage of transplant organs, showing the benefits of milk and dairy ingredients to be far reaching beyond their traditional roles.
Dr Alice Cotter is senior nutrition scientist at The Dairy Council.
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