Your body needs calcium for strong bones and teeth. In addition to bone health, the body also needs calcium for blood clotting, muscle contraction, nerve conduction, blood sugar maintenance and vitamin B-12 absorption. Calcium is available in many of the foods that you eat, but several factors affect how much of the calcium you consume is absorbed.
Recommendations
The Food and Nutrition Board recommends 1,000mg of calcium per day for those aged 19 to 50. For adults over 50, the recommendation is 1,200mg per day. Unfortunately, more than half of Americans do not come close to meeting those recommendations. And for others, the Harvard School of Public Health notes that excessive consumptions of calcium can increase the risk of ovarian and prostate cancers and heart disease. Therefore, you should track how much calcium you are taking in each day to make sure you are meeting and not exceeding these recommendations.
Bone Formation
About 99 percent of the calcium in our body is stored in the bones. When other body tissues need calcium, it is pulled into the blood from the bone stores. This is not a problem for children or those in young or middle adulthood when bone formation exceeds calcium loss. For older adults and postmenopausal women, these rates are completely reversed, resulting more porous bones. Therefore you need to eat and drink calcium-rich foods daily to replace the calcium stores in the bones.
Absorption Enhancers
Several factors affect calcium absorption. Age is one of those factors. Young children tend to absorb calcium readily. As age increases, calcium absorption decreases. Vitamins C and D both aid in the absorption of calcium. Vitamins to Health notes that lactose aids infants in absorbing calcium, but that effect is yet to be seen in adults. It also says a diet with healthy amounts of protein and fat also aid in absorption. It is a fine line. If you consume too much fat or protein, then the body will excrete more calcium and decrease the rate of absorption.
Absorption Inhibitors
Iron and calcium both compete for absorption, therefore they an inhibit the absorption rate of one another. The amount of calcium consumed at one time also affects absorption. The body can only absorb 500mg of calcium at a time. So, you should spread out your calcium-rich foods and supplements over the course of a day, and not try to consume them all at once. In addition, foods such as beets, nuts, spinach, cocoa and berries all contain oxalic acid, which inhibits calcium absorption. Foods containing phytic acid, such as the hulls of grains, seeds and nuts also inhibit calcium absorption. Wait two hours before consuming those food items after eating a source of calcium.
Sources
Your body gets the calcium it needs in one of two ways: You either consume calcium-rich foods or take dietary supplements. Most people think of dairy food as the obvious source of calcium, but many nondairy foods contain calcium. Eating dark green leafy vegetables, baked beans, nuts and fish add calcium to your diet. Many foods, such as cereals, orange juice, breads and soy milk, are also fortified with calcium.
Supplements
To meet the recommended guidelines, you would need to eat three to four servings of calcium-rich foods each day. If you are lactose intolerant or don't like dairy foods, supplements are an option.The Medical University of South Carolina recommends taking a calcium supplement three times a day with a meal to maximize the chance of absorption. Calcium supplements contain either calcium carbonate or calcium citrate. The National Institutes of Health recommends avoiding those made with bone meal as they may contain mercury, arsenic or lead. And as with any supplements, talk to your health practitioner before taking calcium.
References
- Office of Dietary Supplements: Dietary Supplements Fact Sheet: Calcium
- Harvard School of Public Health: Calcium and Milk
- Vitamins to Health: How to Increase Calcium Absorption
- Medical University of South Carolina: Calcium Supplements and Absorption
- NIH National Resource Center for Osteoporosis and Bone Diseases: Calcium Supplements
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