Research has found that bottled water can be just as good a source of calcium as milk.
Research published in the August issue of the American Journal of Clinical Nutrition included a study that focused on high-calcium mineral waters. Women drank the products, which included a traceable form of calcium, and researchers monitored the women's calcium levels as they ate a low-calcium meal. The calcium naturally present in these high-calcium mineral waters was absorbed as well as, or even marginally better than that present in milk.
The study found calcium absorption was boosted when the mineral waters were ingested along with foods; absorption was 20 per cent lower when the waters were ingested during fasting. Three of the studies tested milk directly against waters, and concluded water was as efficient as milk in calcium delivery.
The researcher, Robert Heaney of Creighton University in Omaha, Neb., also conducted a meta-analysis of previous studies involving water products and calcium absorption. He concluded that although some of the tests were conducted with sparkling water, good evidence suggested calcium was bioavailable from high-calcium mineral waters. Indeed, the studies indicated there was little difference between calcium uptake between mineral and sparkling waters.
Heaney noted that those who frequently drank high-calcium mineral water had higher spinal bone mineral density and reduced post-menopausal bone loss.
Calcium intake is generally below recommended levels in the US and many other populations. An increasing number of bottled waters are fortified with calcium.