A new study of dietary calcium suggests that calcium benefits from milk simply cannot be gained from other methods for vulnerable populations such as young girls.
The study, conducted by researchers at Sheffield University, comprised only 86 girls aged 11-12. Half of the girls took a calcium supplement that was added to fruit juice. The control group took fruit juice without the calcium.
As expected, the girls who took the calcium-laced fruit juice improved their bone density by 1.2%. The surprise, however, came when researchers followed-up with the girls two years later — the bone density increase had disappeared.
This is significant, because previous research suggests that bone density obtained from calcium in milk is maintained over time.
Researchers from the National Osteoporosis Society, which conducted the study, suggest that rather than truly increasing bone density, the calcium supplements likely simply suppressed bone remodeling, wherein old bone tissue is broken down and new bone tissue added.
Richard Eastell, chairman of the National Osteoporosis Society told The BBC,
This underlines the need for children and teenagers to take plenty of milk in their diet if they are to build bone strong enough to last a lifetime. Calcium supplements can be used as a substitute if they don’t like milk, but it is important that they keep taking these, or the effect is lost
Samantha Calvert of the UK’s Vegetarian Society argues that the calcium need not come from milk, but could as easily be obtained from sources like spinach, tofu, dried fruit, etc. “Vegetarians are no more likely to be lacking in calcium than any other sectors of society,” Calvert told The BBC.
It would be interesting to see this study replicated, only examining bone density among girls who drink milk vs. those who attempt to obtain an adequate amount of calcium on a vegetarian or vegan diet.
Source:
Milk ‘best calcium source’ for girls. The BBC, December 9, 2001.