Vitamin D and calcium work in concert to keep your bones healthy. Without adequate intakes of vitamin D, your body would be unable to absorb enough calcium for proper bone development and maintenance. If you don't absorb enough calcium from your diet and nutritional supplements, if applicable, the deficiency can lead to reduced bone mass, which can result in osteoporosis. While lethargy and fatigue may indicate nutritional deficits, calcium and vitamin D deficiencies are not necessarily easy to detect by symptoms alone.
About D-3 and Calcium
Vitamin D-3 is the form of the nutrient that your body makes when exposed to ultraviolet-B, or UVB, rays. Other sources include oily fish such as salmon, sardines and mackerel, as well as foods fortified with vitamin D, including cow's milk, soymilk, orange juice and breakfast cereal.
Calcium is the most prominent mineral in your body, and 99 percent of your calcium stores go to keeping your bones and teeth healthy. Good sources of calcium include green leafy vegetables, dairy products and calcium-fortified tofu.
Low calcium or vitamin D levels may produce subtle symptoms or no noticeable symptoms at all, at least initially. Low blood calcium levels may make you feel tired, a symptom that may be accompanied by numbness in the extremities, muscle cramps and decreased appetite. Vitamin D deficiency can lead to a calcium deficiency, as well as rickets in children and osteomalacia in adults. These conditions are characterized by soft or weak bones. Initially, low vitamin D status may also be difficult to detect by symptoms alone, although muscle weakness and bone pain are possible.
A lack of vitamin D and calcium not only affects bone health, but has other repercussions as well. Your body uses calcium to help muscles and blood vessels function properly, for blood clotting and for nerve health, for example. Vitamin D also contributes to nerve and muscle health, as well as the proper function of your immune system. While absorbing adequate amounts of calcium and vitamin D is essential, too much can be toxic.
The Institute of Medicine has established tolerable upper intake limits for both calcium and vitamin D. The maximum intake of calcium not likely to produce adverse effects is 2,500 mg for adults up to age 50 and 2,000 mg for older adults. The upper limit is 2,500 mg for pregnant and lactating women. The tolerable upper intake limit for vitamin D is 100 mcg for all adults. The recommended dietary allowance for calcium is 1,000 mg for men up to age 70 and women up to age 50. Older men and women should aim for 1,200 mg daily. Consult with your doctor about your calcium and vitamin D status and to get supplement and dietary recommendations to ensure adequate intake.
- Linus Pauling Institute at Oregon State University; Calcium; Jane Higdon, Ph.D.; April 2003
- Office of Dietary Supplements: Dietary Supplement Fact Sheet: Calcium
- Linus Pauling Institute; Vitamin D; Jane Higdon, Ph.D.; March 2004
- "Mayo Clinic Proceedings"; Vitamin D Deficiency in Adults: When to Test and How to Treat; Kurt A. Kennel, M.D., et al.; August 2010
- MedlinePlus: Calcium
- Office of Dietary Supplements: Dietary Supplement Fact Sheet: Vitamin D