Although they come from very different sources and play two very different roles within the body, calcium and vitamin D are an important nutrient combination. In fact, the two nutrients rely so heavily on each other that having a deficiency in one often causes a deficiency in the other. Understanding how vitamin D works with calcium can help you better understand the importance of taking in enough of both nutrients on a daily basis.
Calcium & Vitamin D
In order for the body's digestive system to properly absorb calcium, vitamin D must be present. Once vitamin D enters the body, it converts into an active hormone called calcitrol. According to Drugs.com, calcitrol is "the most active known form of vitamin D3 in stimulating intestinal calcium transport." Along with enhancing the absorption of calcium, vitamin D also helps prevent excess elimination of calcium through the urine. By regulating these two processes, an adequate level of vitamin D helps maintain a healthy level of calcium in the body.
Health Benefits
The major function of vitamin D is to maintain healthy blood levels of calcium and phosphorus. However, MayoClinic.com also acknowledges that recent research indicates that vitamin D might also play a protective role against osteoporosis, high blood pressure, autoimmune disorders and certain types of cancer. Calcium, on the other hand, has a much broader scope of responsibilities. A major structural element in teeth and bones, calcium helps maintain their strength and integrity. It also plays a role in regulating the transmission of nerve impulses, muscle contraction, blood vessel changes and hormone secretion.
Recommended Intake
The recommended daily intake for calcium and vitamin D varies by age, according to the National Institutes of Health Office of Dietary Supplements. Until 12 months of age, infants should take in 200 to 260 mg of calcium and 400 international units (I.U.) of vitamin D per day. Children age 1 to 3 need 700 mg of calcium, while children ages 4 to 8 need 1,000 mg of calcium. Between the ages of 9 and 18, they need 1,300 mg of calcium. The recommended intake for calcium decreases to just 1,000 mg between the ages of 19 to 70 -- although females should take in at least 1,200 mg between the ages of 51 and 70. The recommended intake for adults older than 70 is 1,200 mg of calcium, which helps maintain bone strength. In regards to vitamin D, a daily intake of 600 I.U. is recommended between the ages of 1 and 70. Adults over the age of 70 should increase their intake to 800 I.U. per day.
Sources
For many people, the ultraviolet rays of the sun are a major source of vitamin D. However, vitamin D can also be obtained through the diet. Dietary sources of vitamin D include fatty fish, eggs, mushrooms and fortified milk or margarine. Calcium is available in a much wider range of foods. Calcium-rich foods include milk, yogurt, cheese, beans, tofu, kale, broccoli and spinach. If you do not get enough sunshine and are not getting enough vitamin D or calcium from your diet, additional supplementation is also available. However, consult your physician before taking any new supplement to ensure your health and safety.
References
- Linus Pauling Institute: Calcium
- MayoClinic.com; Vitamin D; July 2011
- Office of Dietary Supplements: Vitamin D
- National Institutes of Health (NIH) Osteoporosis and Related Bone Diseases ~ National Resource Center: Calcium and Vitamin D: Important at Every Age
- VeganHealth.org; Bones, Vitamin D, and Calcium; Jack Norris; June 2011
- Drugs.com: Calcitriol
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