Calcium Supplementation Recommendations

Calcium supplementation should be considered when dietary calcium intake is inadequate, but is not routinely recommended for all adults. 1

Recommended Calcium Intake

The Institute of Medicine recommends daily calcium intake of 1000 mg for women 19-50 years and men 19-70 years, and 1200 mg for women over 50 and men over 70 years 1
Upper intake levels should not exceed 2500 mg/day for adults under 50 and 2000 mg/day for those over 50 1
Calcium is a shortfall nutrient in the American diet, making it difficult for many to achieve adequate intake through diet alone 1

Adequate calcium intake is important for skeletal health at all ages 1
Inadequate calcium intake is associated with increased bone loss and fracture risk, particularly in older adults 1, 2
Calcium supplementation has shown benefits for bone health in children, young adults, and menopausal women 3
In combination with vitamin D, calcium may help prevent fractures in vitamin D-deficient nursing home residents, though evidence for fracture prevention in community-dwelling adults is less convincing 4

Dietary sources are the preferred approach to ensuring adequate calcium intake 1
Primary dietary sources include dairy products (milk, yogurt, cheese), fish with bones (sardines), and some vegetables and fruits 2
When dietary sources are insufficient, supplements may be considered 1, 3
Common supplement forms include calcium carbonate (40% elemental calcium) and calcium citrate (21% elemental calcium) 1

Calcium carbonate is the most cost-effective form but should be taken with meals to ensure optimal absorption 3
Calcium citrate can be taken without food and is preferred for individuals with reduced stomach acid or those taking acid-reducing medications 3
The maximum dose of elemental calcium that should be taken at one time is 500 mg for optimal absorption 3
For those requiring supplements, divided doses throughout the day improve absorption 1

Vitamin D plays a crucial role in calcium absorption and bone mineralization 1
The National Osteoporosis Foundation recommends 800-1000 IU of vitamin D daily for adults 50 and older 1
Vitamin D supplementation may be particularly important for those with limited sun exposure, older adults, and those with darker skin living at higher latitudes 4, 2
Serum 25-hydroxyvitamin D levels should ideally be maintained at 30 ng/ml (75 nmol/L) or higher for optimal bone health 1

Calcium supplements may cause gastrointestinal side effects, particularly constipation 1, 3
There is a modest increased risk of kidney stones with calcium supplementation but not with dietary calcium 1
Concerns about cardiovascular risks with calcium supplements have been raised, but evidence is inconsistent and inconclusive 1
The National Osteoporosis Foundation and American Society for Preventive Cardiology state there is moderate-quality evidence that calcium intake from food or supplements has no relationship (beneficial or harmful) to cardiovascular disease risk when kept within recommended limits 1
Calcium supplements should be taken cautiously in those with a history of kidney stones or risk factors for milk-alkali syndrome 5

Assess dietary calcium intake before recommending supplements 1
Prioritize increasing dietary calcium when possible 1, 2
Consider supplements only when dietary intake is inadequate 1
Keep total calcium intake (diet plus supplements) within recommended limits 1
Divide supplement doses throughout the day (no more than 500 mg elemental calcium at once) 3
Consider vitamin D status and supplement as needed 1, 2
Monitor for side effects and adjust supplementation accordingly 5, 3