HOW often do you eat dairy products? A recently published paper by medical professionals and academics may convince you to add more milk, cheese, and yoghurt to your daily diet.
Following an examination of the impact of dairy products, the paper, delivered at the online World Congress on Osteoporosis, Osteoarthritis, and Musculoskeletal Diseases in August, concluded that they were hugely beneficial to the health of muscles and bones. Most of us may have known this already, but what we did not know is that dairy products’ so-called matrix effect means it packs a powerful nutritional punch.
University of Reading professor of food chain nutrition Ian Givens, who joined the Congress, explains the matrix effect as foods amounting to more than the sum of their nutrients. “The effect of a given nutrient may vary dramatically depending on its food source,” he says. “For example, calcium bioavailability is generally much higher when provided by dairy products than by vegetables.”
Having looked at the evidence from international studies, Givens and his fellow researchers concluded that dairy products have a positive effect on health throughout the life cycle, an effect that cannot be attributed to any specific nutrient.
“These effects include growth and bone mineralisation in children and adolescents, attenuation of bone loss and sarcopenia (muscle loss) later in life, and reduction of fracture risk,” says Givens. “This cannot be explained by single nutrients in dairy such as calcium, protein, and vitamin D. It suggests a matrix effect is responsible.”
According to the Irish Osteoporosis Society, 300,000 people in Ireland have osteoporosis, a condition in which bones weaken to the point where they are vulnerable to fracture. Only 15% of cases ever get diagnosed, which leaves many at risk of breaking a bone because of the disease.
Sarah Keogh, a dietitian and nutritionist at the Eat Well Clinic in Dublin, believes dairy helps prevent osteoporosis because of its matrix effect.
“In terms of nutrition, dairy is far better for bones than simply its calcium or protein content,” she says. “It is all about the interaction between the different nutrients and how the body uses them.”
National Dairy Council nutrition manager Dr Marianne Walsh agrees wholeheartedly. “Milk is designed by nature to deliver a rich array of important nutrients,” she says.
“If we were to take the amount of calcium that is found in milk and add it to a glass of water, much of it would simply sink to the bottom. However, in milk, nature has bound the calcium to proteins and phosphorus, which keeps it in suspension. This makes milk one of the best sources of this important nutrient. In addition, each of these nutrients contributes to the maintenance of our bones, so it is not just the calcium working on its own.”
One of the recommendations made in the paper delivered at the Congress is that dietary guidelines should be food based, rather than nutrient based. This is something Keogh and Walsh fully endorse.
“Take sugar and whole grains for example,” says Keogh. “They both count as carbohydrates, but when it comes to the matrix of these foods, there is a huge difference. Sugar delivers little more than simple carbohydrates while whole grains provide a wide array of other ingredients.”
The evidence around how the food matrix affects the overall nutritional impact of a food is growing, says Walsh. “It can influence how well a nutrient is absorbed or how effective it is once eaten. For example, the live cultures in yoghurt or fermented milk can improve lactose digestion.”
These findings need to be widely shared in order to counter the negative messages that are often associated with dairy, according to Keogh. “I have clients who tell me dairy causes cancer but there is no evidence for this,” she says.
However, there are people who are allergic to dairy products. What are the options for them?
“Nothing comes close to dairy in terms of the type of calcium it contains and its levels of protein,” says Keogh. “They are better absorbed by the body. If you have to try other options, tinned sardines and salmon are good as long as you eat the bones.
Fortified tofu is another option and so are fortified plant alternatives to milk.”
There are other important factors to consider when it comes to maintaining bone health. One is getting vitamin D.
“Vitamin D is needed to absorb and use calcium,” says Keogh. “The National Children’s Food Survey found that 97% of children were not getting enough vitamin D and I would be surprised if the same findings weren’t replicated in adults. You can get vitamin D from eggs, oily fish, fortified breads, milks, and cereals or supplements.”
Alcohol consumption and exercise levels are other factors. “People in China and Japan don’t eat much dairy and while osteoporosis is a factor there, it is lessened by the fact that they drink less alcohol than we do, and do more weight-bearing exercise such as yoga and Pilates,” says Keogh.
The Irish Department of Health recommends three servings from the milk, yoghurt, and cheese food group every day. The findings of the World Congress on Osteoporosis, Osteoarthritis, and Musculoskeletal Diseases back up its policy of promoting dairy products as part of a balanced diet.
“Research such as this helps consumers to understand that the nutritional value of dairy foods is difficult to replace or replicate and that dairy provides a unique combination of important nutrients,” says Walsh. “It is a source of nutrition that is widely available across the country that supports good health in general and bone health in particular.”