Quick Answer
The recommended daily calcium intake is 1000-1300 mg per day for adults, depending on age and gender. Getting calcium from foods is preferable to supplements. Consuming more than 2500 mg per day from all sources may increase the risk of kidney stones and cardiovascular disease.
How Much Calcium Do You Need Each Day?
The amount of calcium you need each day depends on your age and gender. The recommended daily intakes are:
- Children 1-3 years: 500 mg
- Children 4-8 years: 800 mg
- Children 9-18 years: 1300 mg
- Adults 19-50 years: 1000 mg
- Women over 50: 1200 mg
- Men over 50: 1000-1200 mg
- Pregnant and breastfeeding teens: 1300 mg
- Pregnant and breastfeeding adults: 1000 mg
These recommended amounts are total calcium from both food and supplements combined. Consuming calcium through foods like dairy, leafy greens, nuts, seeds, beans, and fortified products is ideal. Many people do not get enough calcium from diet alone, which is why supplements can help make up the difference.
Food Sources of Calcium
The best food sources of calcium include:
- Dairy products like milk, yogurt, and cheese
- Fortified plant-based milks and yogurts
- Canned fish with bones like salmon and sardines
- Leafy greens like kale, broccoli, and spinach
- Tofu made with calcium sulfate
- Almonds, sesame seeds, and chia seeds
- Beans, lentils, and peas
- Oranges and other citrus fruits
Dairy products contain the most calcium per serving. For example, one cup of milk has around 300 mg, yogurt has 450 mg, and cheese has about 200 mg per ounce. Leafy greens, beans, nuts, and seeds have a moderate amount of calcium. Getting a variety of calcium-rich foods can help meet your daily needs through diet.
Calcium Supplements
If you have trouble getting enough calcium from food, supplements can help fill the gap. The two main forms of calcium supplements are:
- Calcium carbonate: The most common and inexpensive calcium supplement. Should be taken with food for best absorption.
- Calcium citrate: More easily absorbed, can be taken with or without food. Recommended for people with inflammatory bowel disease or absorption disorders.
Other calcium supplements include calcium gluconate, lactate, and phosphate salts. Calcium citrate is considered the most bioavailable and easiest to digest. The amount of elemental calcium varies by supplement type, so check the dosage on the label.
Most calcium supplements are well absorbed up to 500 mg per dose. Higher amounts may not be fully utilized. Splitting your dose into 500 mg or less at mealtimes can optimize absorption. Avoid taking more than 600-800 mg at one time.
Calcium Absorption and Bioavailability
Only around 30% of calcium from food and supplements gets absorbed. Absorption varies depending on the source:
- Dairy: 32% absorbed
- Supplements: Up to 40% absorbed depending on type
- Vegetables: 5-8% absorbed
- Grains: 1% absorbed
Calcium absorption decreases with age. Older adults often make less stomach acid, lowering the breakdown of calcium salts. Absorption can also be affected by health conditions, medications, and dietary factors.
The bioavailability refers to how much absorbed calcium gets utilized in the body. Dairy products and supplements tend to have higher bioavailability than plant sources of calcium.
Benefits of Calcium
Getting adequate calcium is important for:
- Bone health and strength
- Muscle function
- Nerve signaling
- Hormone secretion
- Enzyme activation
- Heart rhythm
- Lowering risk of osteoporosis and fractures
Over 99% of calcium in the body resides in bones and teeth. The other 1% plays crucial roles in vascular contraction, muscle function, nerve transmission, intracellular signaling, and hormonal secretion.
Consuming enough calcium supports bone mineral density to help prevent osteopenia and osteoporosis. Getting sufficient vitamin D and doing weight-bearing exercise are also key for bone health.
Are You Getting Enough?
Many people do not consume optimal amounts of calcium for their age group. According to national surveys:
- 9-18 years old: Less than 15% meet calcium recommendations
- 19-50 years old: Less than 5% of women and 25% of men meet calcium recommendations
- Over 50 years: Less than 10% meet calcium recommendations
Not meeting calcium needs over long periods can lead to diminished bone density and strength over time. In children and teens, inadequate calcium intake can impair optimal bone growth and development.
Factors that increase the risk of low calcium intake include:
- Avoiding dairy products
- Eating few leafy greens, nuts, seeds, beans, and seafood
- Eating a diet high in processed foods
- Having lactose intolerance or allergy
- Following a vegan diet
- Having an eating disorder or restrictive diet
Getting enough vitamin D and exercising regularly also help optimize calcium absorption and utilization for bone health.
Signs of Low Calcium
Signs and symptoms that may indicate low calcium levels include:
- Muscle cramps or spasms
- Numbness or tingling in hands, feet, or face
- Difficulty sleeping
- Bone fractures
- Brittle nails
- Dry scaly skin
- Weak or brittle teeth
Chronically low calcium can lead to osteopenia or osteoporosis later in life. Fractures, stooped posture, and loss of height can occur.
However, low dietary calcium alone is rarely the cause of serious deficiency. An underlying medical condition like vitamin D deficiency, malabsorption, or kidney disease typically contributes.
Can You Get Too Much?
Consuming very high amounts through diet or supplements over time can raise potential health risks:
- Kidney stones
- Prostate cancer
- Cardiovascular disease
- Constipation
- Kidney damage
The Tolerable Upper Intake Level (UL) for calcium is 2500 mg per day in adults 19-50 years old. This is the maximum amount unlikely to cause adverse health effects.
Consuming above the UL long-term may increase cardiovascular risk based on some research. One study found a 20% greater risk of heart disease when calcium intake exceeded 1400 mg daily.
High calcium may also contribute to arterial calcification and kidney stones. But results are mixed, and more studies are needed on exact risk levels.
Calcium Toxicity
Excessively high calcium levels in the blood is known as hypercalcemia. Potential causes include:
- Hyperparathyroidism
- Cancer
- Multiple myeloma
- Sarcoidosis
- Paget’s disease
- Prolonged immobilization
- Milk-alkali syndrome
- Excessive calcium or vitamin D intake
Taking very high amounts like 10,000+ mg per day long-term can potentially result in milk-alkali syndrome, with symptoms like:
- Nausea
- Vomiting
- Headache
- Confusion
- Fatigue
- Kidney stones
- Kidney failure
This condition is rare now since antacids with calcium carbonate are less common. Most cases involve excessive calcium carbonate intake when doses exceed 4,000 mg daily.
Calcium and Medications
Some medications can interact with calcium supplements, including:
- Blood thinners like Coumadin (warfarin)
- Antibiotics like ciprofloxacin and levofloxacin
- Levothyroxine for hypothyroidism
- Digoxin for heart failure
- Phenytoin for seizures
- Steroid medications like prednisone
Calcium can decrease absorption of these medications when taken at the same time. To prevent interactions, take calcium supplements at least 2-3 hours apart from other medications.
People with health conditions like parathyroid disease, cancer, renal failure, and malabsorption syndrome should not take calcium supplements unless directed by a healthcare provider.
Safe Upper Limit
Most healthy adults can safely consume up to:
– 2,500 mg calcium per day from food and supplements combined
– 1,000-1,200 mg per dose, split among 3-4 doses per day
Higher amounts exceeding 1,500 mg per dose may increase the risk of kidney stones and cardiovascular issues. Sticking under 2,500 mg daily from all sources is unlikely to cause toxicity or adverse effects in most people.
Some populations should not exceed the recommended daily intakes for their age group without medical supervision. This includes people with chronic kidney disease, hyperparathyroidism, a history of calcium-containing kidney stones, and sarcoidosis.
Testing Your Calcium Levels
Blood calcium levels between 8.5-10.5 mg/dL are considered normal for adults. Levels are regulated by parathyroid hormone (PTH) and vitamin D.
Most cases of low calcium are due to vitamin D deficiency. Blood calcium drops only when deficiency is severe. Symptoms may appear before abnormal calcium levels.
Hypercalcemia is more likely in people with medical conditions. If excess calcium intake is suspected, reducing or stopping supplements can help normalize levels.
Doctors can check blood calcium if symptoms persist or risk factors exist. Underlying disorders are typically treated first before calcium supplementation.
Increasing Your Calcium Intake
If your diet falls short, you can increase your daily calcium with these steps:
- Eat more dairy products like yogurt, cheese, and milk
- Try fortified plant milks and juices
- Add leafy greens to meals and snacks
- Eat canned fish 2-3 times per week
- Snack on nuts, seeds, and dried beans
- Consider a daily supplement
- Limit foods that impair absorption like excess sodium, caffeine, and protein
Getting enough vitamin D also optimizes calcium absorption. Weight-bearing exercise and resistance training helps build strong bones.
Key Takeaways
The ideal calcium intake per day depends on your age and gender:
– 1,000-1,300 mg daily for most adults
– No more than 2500 mg per day from food and supplements combined
Taking 1,000-1,200 mg per dose, split in 2-3 doses over the day, is typically recommended.
Eating a balanced diet with a variety of natural calcium sources is best. Dairy products have the highest concentration per serving.
High doses over 2,500 mg daily may pose risks like kidney stones in susceptible people. Very high amounts over 10,000 mg can lead to milk-alkali syndrome.
Check with your doctor before taking calcium supplements if you have any medical conditions or take medications that interact with calcium.
