Maintaining bone health is essential for physical wellbeing, and when bone density is lost osteoporosis and fractures can occur. This is a particular risk for post-menopausal women, 10 to 11% of whom are affected by osteoporotic fractures.

Current treatment options include hormone-replacement therapy or the use of bisphosphonates, both of which can have side effects. Now, Professor Marlena Kruger, Dean of Graduate Research and Researcher Development at Massey University, is leading a platform of research investigating a variety of nutritional options that could help promote bone health.

Professor Kruger, who also holds the post of Professor of Nutritional Physiology at the Massey Institute of Food Science and Technology, has research interests which include lipids and bone health, the maintenance of mobility with ageing and the use of nutrition to support bone and joint health at different stages of life and among different ethnic groups.

Providing the scientific evidence

Anlene™ is a milk fortified with extra calcium and vitamin D. It is an example of a functional food targeted at improving bone health. Anlene™ was designed for Asian women on the proposition that drinking calcium-fortified milk throughout life would strengthen women’s bones sufficiently to prevent osteoporosis in countries where the condition is rife. But in order for the dairy industry to market the product, scientific evidence for its effectiveness was needed.

Professor Kruger researched the impact of calcium- and vitamin-fortified milk products and bioactives from milk on bone and joint health maintenance, using cell-based assay systems to screen for bioactivity, as well as using pre-clinical models and human intervention trials in New Zealand and Asia. These studies, funded by Fonterra Brands Singapore Ltd, demonstrated how milk and other dairy foods can influence bone growth or slow decay.

The role of Kiwi foods

Professor Kruger is now involved in further research into specialised nutrition and functional foods related to bone health. For example, she is investigating the interaction between New Zealand foods such as kiwifruit, mānuka honey or fish oils and soy phytoestrogens, in collaboration with researchers at the National Institute of Health and Nutrition in Tokyo. So far, results show that carotenoids from kiwifruit modulate bone breakdown, and that mānuka honey could act as a prebiotic, changing the bacterial population in the gut and altering mineral bioavailability as well as modulating molecular control of bone formation or resorption.

In her assessments of bone health, Professor Kruger has increasingly been looking at different ethnicities and the factors that affect bone health in each group. For example, she has studied the differences in the rate of bone loss in both males and females in seven countries in Asia, confirming that environment, diet and lifestyle have significant effects on bone health in these countries.

Counter to the general assumption that African women have strong bones and experience fewer fractures, more recent work showed that urban black post-menopausal women in South Africa in fact lose bone at similar rates to older Caucasian women. In the African women, obesity is also not a protective factor for bone density.