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Calcium

Mineral Unit: mg

Essential mineral for strong bones and teeth. Also critical for muscle contraction, nerve signalling, and blood clotting.

Recommended Daily Allowance (RDA)

1,000
Adult Male
mg/day
1,000
Adult Female
mg/day
Daily Requirements by Life Stage 16 groups
Life StageRDA / AI (mg/day)Upper Limit (mg/day)
Children 1-3 years7002,500
Children 4-8 years1,0002,500
Males 9-13 years1,3003,000
Females 9-13 years1,3003,000
Males 14-18 years1,3003,000
Females 14-18 years1,3003,000
Males 19-30 years1,0002,500
Females 19-30 years1,0002,500
Males 31-50 years1,000
Females 31-50 years1,000
Males 51-70 years1,0002,000
Females 51-70 years1,2002,000
Males 70+ years1,2002,000
Females 70+ years1,2002,000
Pregnancy1,0002,500
Lactation1,0002,500

Top Foods Highest in Calcium

Amount per 100g serving. Values in mg per 100g.

Foods Highest in Calcium (Table)

#FoodPer 100gGroup
1Leavening agents, baking powder, double-acting, straight pho7,364 mgBaked Products
2Leavening agents, baking powder, double-acting, sodium alumi5,876 mgBaked Products
3Leavening agents, baking powder, low-sodium4,332 mgBaked Products
4Desserts, rennin, tablets, unsweetened3,733 mgSweets
5Spices, basil, dried2,240 mgSpices and Herbs
6Tofu, dried-frozen (koyadofu), prepared with calcium sulfate2,134 mgLegumes and Legume Products
7Spices, savory, ground2,132 mgSpices and Herbs
8Whey, acid, dried2,054 mgDairy and Egg Products
9Spices, marjoram, dried1,990 mgSpices and Herbs
10Spices, thyme, dried1,890 mgSpices and Herbs
11Spices, dill weed, dried1,784 mgSpices and Herbs
12Spices, celery seed1,767 mgSpices and Herbs
13Spices, sage, ground1,652 mgSpices and Herbs
14Seeds, sisymbrium sp. seeds, whole, dried1,633 mgNut and Seed Products
15Smelt, dried (Alaska Native)1,600 mgAmerican Indian/Alaska Native Foods
16Spices, oregano, dried1,597 mgSpices and Herbs
17Spices, dill seed1,516 mgSpices and Herbs
18Formulated bar, MARS SNACKFOOD US, SNICKERS MARATHON Double 1,495 mgSnacks
19Spearmint, dried1,488 mgSpices and Herbs
20Beverages, Cocoa mix, low calorie, powder, with added calciu1,440 mgBeverages

Health Effects of Calcium

Function

Calcium is the most abundant mineral in the body, with 99% stored in bones and teeth. It is essential for bone structure, muscle contraction, nerve transmission, blood clotting, and enzyme activation.

Deficiency Signs

Chronic calcium deficiency leads to decreased bone mineral density, osteopenia, osteoporosis, and increased fracture risk. Acute deficiency causes muscle cramps, numbness, and cardiac arrhythmias.

Excess / Toxicity

Excess calcium (>2,500mg/day) can cause kidney stones, constipation, and may impair absorption of iron, zinc, and magnesium. Very high intake may increase cardiovascular risk.

Absorption & Interactions

How It’s Absorbed

Absorbed primarily in the duodenum via active vitamin D-dependent transport (at low intakes) and passive paracellular diffusion throughout the small intestine (at higher intakes). Typical absorption rate is 25-35%.

Key Interactions
Vitamin D Enhancer
Vitamin D is essential for calcium absorption; without adequate D, only 10-15% of dietary calcium is absorbed vs 30-40% with adequate D
Iron Inhibitor
Calcium inhibits both heme and non-heme iron absorption when consumed together; separate by 2+ hours if iron status is a concern
Zinc Inhibitor
High calcium intakes may modestly reduce zinc absorption
Magnesium Inhibitor
Very high calcium:magnesium ratios may impair magnesium absorption
Oxalic Acid Inhibitor
Oxalate in spinach, rhubarb, and beet greens binds calcium, reducing its bioavailability to as low as 5%

Estimated Calcium Adequacy by Country

Estimated from national food supply composition (FAO food balance sheets). Shows food supply availability relative to Estimated Average Requirement (EAR), not actual intake. Does not account for fortification, supplements, or distribution inequality.

180 countries102 below 50% EAR24 above 100% EARAvg: 52% EAR
% of EAR from food supply:0-25%25-50%50-75%75-100%100-150%>150%

Frequently Asked Questions

How much Calcium do I need per day?

Adult males need 1,000 mg/day and adult females need 1,000 mg/day.

Which food has the most Calcium?

The food highest in Calcium is Leavening agents, baking powder, double-acting, straight phosphate with 7,364 mg per 100g.

What does Calcium do in the body?

Essential mineral for strong bones and teeth. Also critical for muscle contraction, nerve signalling, and blood clotting.