Controversies in medicine: the role of calcium and vitamin D supplements in adults

Abstract

Summary Vitamin D is made in the skin when exposed to sunlight, so deficiency is usually the result of low sunlight exposure (eg, in frail older people and in individuals who are veiled). Calcium and/or vitamin D supplements have been used for the prevention and treatment of osteoporosis. The major trials in community‐dwelling individuals have not demonstrated fracture prevention with either calcium, vitamin D, or their combination, but the results of a large study in vitamin D‐deficient nursing home residents indicated a reduced fracture incidence. Trials show that vitamin D increases bone density when winter 25‐hydroxyvitamin D levels are below 25–30 nmol/L. However, assay expense and variability suggest that supplements are better targeted based on clinical status to frail older people and possibly to people with dark skin living at higher latitudes. A daily dose of 400–800 units (10–20 μg) is usually adequate. Parenteral antiresorptive drugs can cause hypocalcaemia in severe vitamin D deficiency (< 25 nmol/L), which should therefore be corrected before treatment. Clinical trials have not demonstrated benefits of vitamin D on non‐skeletal endpoints. Calcium supplements in healthy individuals are not needed, nor are they required in most people receiving treatment for osteoporosis, where they have not been shown to affect treatment efficacy. Calcium supplements cause constipation, bloating and kidney stones, and some evidence suggests they may cause a small increase in the risk of myocardial infarction. Low dose vitamin D is safe, but high doses result in more falls and fractures. Current evidence does not support the use of these supplements in healthy community‐dwelling adults.

Nutritional Support and Physical Modalities for People with Osteoporosis: Current Opinion

“…The dietary sources of vitamin D include salt-water oily fish and liver, egg yolks, margarine, some yogurts, cheeses, cereals, and vitamin D-fortified milk and orange juice. However, the major source of vitamin D3 for most humans is synthesis in the skin under the influence of UV light [1,15]. The prevalence of vitamin D deficiency has been reported to be higher in the elderly population.…”

“…This might be due to insufficient skin exposure to sunlight and reduced efficacy of vitamin D synthesis. Indoor styles of living and clothing now result in low sun exposure [15,20]. UV irradiation, half the minimal erythematous dose, on 1000 cm 2 of skin on the backs of elderly participants three times per week was found to be as effective as the oral intake of 400 IU vitamin D [20].…”

“…In a report by the National Osteoporosis Foundation, people older than 50 years are recommended to take at least 800-1000 IU of vitamin D daily because they are at greater risk of vitamin D deficiency [21]. However, a recent review revealed that supplements are better targeted based on clinical status to frail older people and possibly to people with dark skin living at higher latitudes [15]. Recent trials showed that vitamin D increases bone density when 25-hydroxyvitamin D levels are below 25-30 nmol/L.…”

“…Recent trials showed that vitamin D increases bone density when 25-hydroxyvitamin D levels are below 25-30 nmol/L. A daily dose of 400-800 IU (10-20 µg) is usually adequate [15]. Recent evidence has revealed that low dose vitamin D is safe, but high doses result in more falls and fractures [15,16].…”

“…However, current evidence has shown that routine calcium and vitamin D supplements in healthy individuals are not needed. In patients with an adequate vitamin D status and a normal calcium intake, routine calcium and vitamin D supplements are not required in most people receiving treatment for osteoporosis, where routine use has not been shown to affect treatment efficacy [15,16]. Several new therapeutic agents are now available for the treatment of osteoporosis [3].…”