University of Limerick: Making the most of the daily pinta

Most people of a certain age can recall health campaigns urging us all to drink our “daily pinta”. Various claims were made for its health-giving properties and now it turns out that not only were many of these claims true but milk can also help athletes perform better and the rest of us to age more healthily.

And these properties are the subject of the €21.7 million Food for Health Ireland phase 2 (FHI2) research programme at the University of Limerick. A particular element of the programme will explore the role of milk proteins in healthy aging and performance nutrition.

“Our principal expertise is in human skeletal muscle”, explains professor of sport and exercise sciences Phil Jakeman. “Healthy active aging and improving sports performance have a lot in common as far as muscle is concerned. As we age the amount of muscle and lean tissue mass begins to decrease. This can lead to frailty, disability and loss of independence in older adults.

“Conversely, high performance athletes generally try to increase muscle mass and muscle function that has to recover and adapt quickly to sustain and improve optimal performance. Many of the nutrient and metabolic regulators of these effects on muscle in ageing and performance overlap.” Part of the research is looking at the interaction between the nutrient effects of the food we ingest and the physical exercise we take. “The timing of our food intake can have an impact on the effect of the physical activity. There is a strong interaction between the nutrient effect and the physical activity effect.”

An example of this interaction is an athlete seeking to add muscle mass. They tend to take protein supplements after exercise and this provides the fuel for the muscle building. Taking the supplements before the exercise would not deliver the same effect. And the proteins in these supplements tend to be derived from milk.

This is where the link with healthy ageing comes in. Prof Jakeman explains that the point at which our bodies begin to decline is a lot earlier than most of us think. We reach maturity at between 20 and 30 and at this point the decline begins.

Muscles start declining
"Most of us are familiar with the deterioration in bone density which can develop into osteoporosis in later life," he points out. "But not many people are aware that our muscles start declining at that point as well in a process known as sarcopenia. We only really become aware of it when we can't run or lift our luggage into the overhead bin in an airplane anymore."

The natural solution is to take exercise to maintain muscle mass as we get older but it is not as simple as that. “Aging tends to blunt the process of nutrition and exercise so we don’t get quite the same effects when we are 60 years of age as we did when we were 30,” Prof Jakeman points out. “What we are looking at is optimising our food intake so that it has the maximum impact and promotes the physical process as we grow older. We are looking for bioactive derivatives of milk proteins which will help overcome this blunting as we get older.” And the detective work to find these bioactive derivatives is being carried out by researchers from the university’s department of life sciences as Prof Dick FitzGerald explains.

"Milk is a valuable and highly complex biological material, composed of multiple constituents such as proteins, carbohydrates, fats, vitamins and minerals. In FHI2, milk is the source material potentially providing an innovative pipeline of bio-functional ingredients to the consumer market. "We are using enzymes, natural food-grade catalysts, to break down the proteins in milk to release a new range of biofunctional ingredients, known as peptides, which may have a positive impact on human health. Our work brings together diverse expertise, for example, protein chemistry, separation science and biochemistry, where milk proteins are specifically modified to release a number of potential health benefits. This research provides a pipeline of new generation ingredients that support Prof Jakeman and other researchers within the FHI programme who are investigating the effect of milk peptides on healthy ageing, glycaemic and appetite management."

Benefits they can offer
Prof FitzGerald's team identifies and isolates these peptides based on the specific properties being sought. Once they have been produced it is up to Prof Jakeman and his team to assess them. According to Prof FitzGerald there are also potential benefits for people suffering from Type 2 Diabetes. "We are looking for peptides with effects associated with specific metabolic pathways," he notes. "These could be linked to glucose serum concentration and the peptides we are producing could help in terms of how the body controls these serum levels – this is linked to Type 2 Diabetes."

Prof Jakeman is excited by the possibilities. “We are using our knowledge about how athletes train for health aging and that can only be good,” he says. “We are starting to understand more about the processes involved and about what the right foods are to eat and when. For example, we eat about 1,000 meals a year but we tend to eat a lot of protein just once a day with our dinner. This is reducing our opportunities to ingest protein to one third and muscles can only absorb so much protein. If we were to divide the protein across the three meals it could have a much better effect. We are doing the same in terms of finding the right bioactive ingredients in milk which can be incorporated into foodstuffs which people can eat to promote the muscle building process.”