Calcium, Vitamin D Impact Bones' Response to Exercise

By Brett Spiegel

You may know to eat carbs before you exercise to boost energy and eat protein after your workout to promote muscle. But the time of day you take your supplements -- specifically calcium and vitamin D — may also affect how your bones respond to exercise, according to a new study presented today at The Endocrine Society's 95th Annual Meeting in San Francisco.

Researchers at the University of Colorado Anschutz Medical Campus tracked calcium and vitamin D levels of 52 male cyclists between the ages of 18 and 45 who were given supplements of both either 30 minutes prior to an exercise regimen or one hour afterward.

Through an analysis of the cyclists' sweat, researchers observed that calcium levels decreased in the blood after exercise whether a supplement was taken before or after working out. However, ingesting a supplement beforehand minimized this decrease which scientists believe may hold larger implications on how bones react to intense physical activity.

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"These findings are relevant to individuals who engage in vigorous exercise and may lose a substantial amount of calcium through sweating," said Vanessa D. Sherk, PhD, lead study author and postdoctoral research fellow. "Taking calcium before exercise may help keep blood levels more stable during exercise, compared to taking the supplement afterwards, but we do not yet know the long-term effects of this on bone density."

Previous research has suggested that rigorous and competitive training among road cyclists results in a loss of bone mineral density attributed to a decrease in calcium. A deficit in calcium, say researchers, increases parathyroid hormones which are responsible for breaking down bones.

Nonetheless, make sure to consult your doctor before beginning any sort of supplement plan. And remember that the best source of vitamins and minerals comes from maintaining a healthy and balanced diet.

"Be aware of food and drug as well as drug and drug interactions," said Bonnie Taub-Dix, RD, author of Read It Before You Eat It and Nutrition Intuition blogger for Everyday Health. "Foods containing iron like spinach and leafy greens may diminish calcium absorption. Dairy products enhance absorption. Certain antibiotics and high blood pressure meds may also impact absorption so check with your doctor or pharmacist."

Calcium, Vitamin D Impact Bones' Response to Exercise originally appeared on Everyday Health.