In a previous blog we reported on the timing, quality and quantity of protein intake in the prevention of the age-related decline in muscle mass, termed sarcopenia. This month saw the launch of a study designed to evaluate the efficacy of a novel nutrient supplement designed to assist in the prevention of the age-related decline in skeletal mass, i.e. osteopenia. Funded by an Enterprise Ireland Innovation Partnership Project Grant in collaboration with Dairygold the project recognises the pivotal role of bone turnover in the maintenance of bone health. Bone turnover is a term used to describe the normally balanced rate of bone resorption and bone formation. As a result of this activity 5-10% of the skeleton is ‘turned over’ each year as bone remodels for essential maintenance and repair, an important component of overall bone health. It follows that dysregulation of the balanced resorption and formation processes can cause a greater deterioration in bone health when overall rates of bone turnover ae high, as is the case in developmental growth to adulthood in both sexes and in during immediate years post-menopause in women (Figure 1).
Because bone health is monitored by change in bone mineral density (BMD: measured by DXA) most relate bone health to its mineral content and the requirement for adequate dietary intake of calcium (recommended as 800-1200mg per day) and vitamin D (20ug per day) which assists in the absorption of calcium. Few, however, would relate the structural integrity of bone, and hence bone health, to its protein content, composed principally of type I collagen. Yet, integral to bone turnover is the rate of collagen turnover and this, we find, is highly nutrient sensitive.
Earlier this year a pilot study conducted by researchers Dr Manjula Hetterachchi and Rachel Cooke concluded that the diurnal (24 h) rate of bone turnover could be regulated by an appropriately timed ingestion of a milk protein-based supplement, specifically prepared for the study by Dairygold. The study launched this month evaluates the change in bone health following a long-term (6-month) period of supplementation in post-menopausal women. If successful we would hope to extend this work further to incorporate a 2nd major lifestyle factor, physical activity, as a co-stimulus in maintenance of bone health.
Professor Phil Jakeman is a professor in Exercise Physiology in the department of Physical Education & Sport Sciences at the University of Limerick. His current research interests include Human Exercise Science; Biochemistry of Exercise; Growth Factors; Bone Turnover; Muscle Adaptation; Nutrition and metabolism. View Phil’s profile on Research Gate or contact Phil on phil.jakeman@ul.ie 
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