Recommended Daily Calcium Intake for Adults Not Consuming Dairy
A well adult who does not consume dairy products should aim for 1000 mg/day of elemental calcium (ages 19-50 and men 51-70) or 1200 mg/day (women over 50 and all adults over 70), obtained primarily through non-dairy dietary sources supplemented as needed to reach these targets. 1
Age and Sex-Specific Targets
The calcium requirements vary by demographic group:
- Adults aged 19-50 years and men aged 51-70 years: 1000 mg/day of elemental calcium 1
- Women over 50 years: 1200 mg/day 1, 2
- All adults over 70 years: 1200 mg/day 1, 3
- Upper safe limit: 2000 mg/day for adults over 50 years; 2500 mg/day for adults under 50 years 1, 2
Practical Approach for Non-Dairy Consumers
Step 1: Estimate Non-Dairy Dietary Calcium Intake
Most adults consume approximately 300 mg of calcium per day from non-dairy sources such as vegetables (particularly broccoli and kale), grains, and fortified foods. 4 This baseline is significantly lower than the 900-1200 mg typically obtained by dairy consumers, who derive about 70% of their calcium from dairy products. 4, 1
Step 2: Identify the Calcium Gap
For a non-dairy consumer relying solely on typical non-dairy foods (~300 mg/day), there is a substantial deficit:
- Young to middle-aged adults: Need an additional 700 mg/day to reach 1000 mg target 1
- Older adults: Need an additional 900 mg/day to reach 1200 mg target 1, 3
Step 3: Prioritize Calcium-Rich Non-Dairy Foods
Before considering supplements, maximize intake from non-dairy calcium sources:
- Leafy green vegetables (broccoli, kale, bok choy) offer excellent calcium absorption, potentially superior to supplements 4
- Calcium-fortified foods (plant-based milks, orange juice, cereals) can provide substantial amounts 1
- Fish with bones (sardines, canned salmon) 5
- Legumes, nuts, and seeds contribute meaningful amounts 4
Step 4: Bridge the Gap with Supplements if Needed
If dietary modification cannot meet the recommended intake, calcium supplements should be added. 1, 2
Supplement selection:
- Calcium carbonate (40% elemental calcium): Most economical option, but must be taken with meals for optimal absorption 2, 3
- Calcium citrate (21% elemental calcium): Can be taken without food; preferred for those with reduced gastric acid or gastrointestinal side effects 2, 3
Dosing strategy:
- Divide supplemental doses to ≤500 mg at a time to optimize absorption and minimize gastrointestinal side effects 1, 3
- Spread calcium intake throughout the day rather than taking it all at once 3, 6
Essential Cofactor: Vitamin D
Adequate vitamin D is absolutely essential for calcium absorption, regardless of calcium source. 1, 2
- Recommended vitamin D intake: 600-800 IU/day for adults 1, 3, 6
- Target serum 25(OH)D level: At least 20-30 ng/mL 2
- Vitamin D should be co-administered with calcium supplementation to ensure effectiveness 1, 2
Critical Safety Considerations
Kidney Stone Risk
Calcium supplementation (but not dietary calcium) modestly increases the risk of nephrolithiasis. 1, 2 This represents approximately 1 additional case per 273 women supplemented over 7 years. 2 Dietary calcium from food sources does not carry this risk and may actually be protective. 1
Cardiovascular Concerns
The evidence for cardiovascular risk with calcium supplements remains inconsistent and inconclusive, though this concern has been raised in the literature. 1, 3
Upper Limits
Do not exceed 2000 mg/day total calcium intake (from all sources combined) for adults over 50 years, as intake above this level increases risk of adverse effects without additional benefit. 1, 2, 5
Common Pitfalls to Avoid
- Taking large single doses: Absorption is limited to ~500 mg at a time; excess is wasted 1, 3
- Neglecting vitamin D: Calcium supplementation without adequate vitamin D substantially reduces skeletal benefits 2
- Counting only supplements: The 1000-1200 mg target represents total intake from diet plus supplements combined 2
- Assuming all calcium sources are equal: Some vegetables like broccoli and kale may offer superior absorption compared to supplements 4