Evidence from a study by UK researchers indicates that children should carry out 25 to 40 minutes of vigorous activity and intake at least 700-800 milligrams of dietary calcium per day, roughly the equivalent of three 8 oz. glasses of milk.
Using food diaries and accelerometers, researchers at the University of Wales and the University of Exeter tracked the behaviour of 38 girls and 38 boys between 8 and 11 years old, pinpointing the 'synergistic effect' of high levels of calcium intake and vigorous exercise.
"In reality we are talking about the sort of energy you would expect kids to expend when playing around outside with a ball or rope," said researcher Dr.Eston.
Dietary calcium has long been implicated in bone health, contributing to stronger bones and reducing the risk of osteoporosis in later life. Osteoporosis, the gradual decline in bone mass with age, is linked to common fractures of the hip and the vertebrae. It is estimated that hip fractures alone cost about $10 billion (€8.12) per year in the US.
This latest study reported in the October 2004 issues of the Journal of Applied Physiology stands up against research from the US published the June 2004 issue of Journal of Pediatrics that suggested exercise is more influential than calcium intake in determining bone strength in young women. They found that daily calcium intake had no significant impact on bone gain during adolescence.
"Although calcium intake is often cited as the most important factor for healthy bones, our study suggests that exercise is really the predominant lifestyle determinant of bone strength in young women," said professor Tom Lloyd from the Penn State College of Medicine.
"There was only a small positive relationship between calcium intake and bone variables, but a significant association between sports exercise score and young adult bone mass and strength," he added.
But the dairy industry is enjoying the impact of increased consumer awareness of bone health, a segment of the growing functional foods market that overall is tipped to double in the UK alone in the next five years from £835 to £1.7 billion.
In addition, milk is experiencing its strongest gains in the flavoured dairy beverage segment, that principally targets children, with growth in the US, for example, expected to rise by 8.4 per cent annually until 2006.