Calcium

Effects and Benefits

Core Identification

Common Names:
- Calcium
- Ca
- Bone mineral

Latin Name: N/A (Elemental mineral, chemical symbol Ca)

Category: Mineral

Uses

Traditional Uses

• Bone and teeth strengthening - Used across cultures throughout history
• Antacid for digestive upset - Historical medicite use of calcium-containing compounds
• Muscle cramp relief - Traditional remedy for leg cramps and spasms

Modern Uses

• Osteoporosis Prevention and Treatment - Reduces bone loss and fracture risk | Research quality: Strong
• Key findings: In the Women's Health Initiative study, women who took calcium (1,000 mg) and vitamin D daily for 7 years had a 29% reduction in hip fractures. Both nutrients together reduce vertebral fractures and lower parathyroid hormone levels that can cause bone loss.

• Source citations: Moyad - The Supplement Handbook; Wilen - Healing Remedies

• Bone Density Maintenance - Supports bone mineral density throughout life | Research quality: Strong

• Key findings: Daily calcium supplements of 1,000 mg help prevent bone loss in older women, particularly during winter months when vitamin D levels are naturally lower. Combining calcium with vitamin D may reduce non-vertebral and hip fracture risk by 30-40%.

• Source citations: Brewer - TDT Encyclopedia of Vitamins; Stewart - Living the Good Long Life

• Premenstrual Syndrome (PMS) - Reduces PMS symptoms | Research quality: Moderate

• Key findings: Supplementing with 1,200 mg calcium carbonate daily decreases water retention, food cravings, and pain of PMS by 18% compared to placebo.

• Source citations: Moline - The Doctors Book of Natural Health Remedies

• Blood Pressure Support - May help maintain healthy blood pressure | Research quality: Moderate

• Key findings: Low calcium intakes have been linked with high blood pressure and stroke. Calcium supplements may protect against pre-eclampsia development in pregnancy.

• Source citations: Brewer - TDT Encyclopedia of Vitamins

• Colon Health - May support colorectal health | Research quality: Preliminary

• Key findings: Good intakes of calcium may support colon health, possibly by buffering bile acid effects.
• Source citations: Brewer - TDT Encyclopedia of Vitamins

Active Compounds

Primary Active Ingredients:
- Elemental calcium - The actual calcium content available for absorption; varies by supplement form
- Calcium carbonate - 40% elemental calcium; most concentrated and economical form
- Calcium citrate - 21% elemental calcium; better absorbed without food
- Calcium phosphate - Similar concentration to carbonate; same type found in milk
- Calcium gluconate/lactate - Lower concentration; well absorbed but requires more pills

Dosage Information

Standard Dosage:
- Form: Tablets, capsules, chewables, liquids
- Amount: 1,000 mg daily (adults under 50)
- Frequency: Divided into 2-3 doses of no more than 500 mg each

Therapeutic Dosage:
- Form: Tablets or capsules
- Amount: 1,200 mg daily (adults over 50, or those with increased needs)
- Purpose: Osteoporosis prevention, bone loss prevention
- Duration: Ongoing as part of daily supplementation

Maximum Safe Dosage:
- Daily maximum: 2,000-2,500 mg from all sources (food and supplements)
- Warning threshold: Doses exceeding 1,200-1,400 mg daily may increase cardiovascular risk and kidney stone formation

Bioavailability Notes:
- Only 30-40% of dietary calcium is typically absorbed
- Absorption decreases as single-dose amounts increase (take no more than 500 mg at once)
- Calcium carbonate requires stomach acid for absorption; take with meals
- Calcium citrate absorbs well with or without food; better for those with low stomach acid
- Vitamin D significantly increases calcium absorption (by 30-80%)
- High-fiber diets and phytates (from wheat bran, unleavened bread) reduce absorption

How to Take It

Timing:
- Calcium carbonate: Take immediately after meals for best absorption
- Calcium citrate: Can be taken any time of day, with or without food
- Evening doses may be beneficial as calcium flux is greatest at night when growth hormone is secreted
- Space doses throughout the day rather than taking all at once

Synergies - What It Works Well With

Complementary Supplements:
1. Vitamin D - Essential for calcium absorption; without adequate D, calcium absorption drops significantly | Recommended 600-1,000 IU daily
2. Vitamin K - Necessary for proper bone mineralization; helps direct calcium into bones | Higher vitamin K intake associated with reduced hip fracture risk
3. Magnesium - Works with calcium for bone structure; take separately as can interfere with each other's absorption | Take calcium in morning, magnesium at night
4. Boron - Improves calcium absorption and reduces urinary calcium excretion | Found in apples, avocados, nuts
5. Strontium - Research shows it may work synergistically with calcium for bone formation | Take separately from calcium

Avoidance - What NOT to Combine With

Supplement Interactions:
1. Iron - Calcium inhibits iron absorption | Take at different times of day
2. Zinc - High calcium doses can reduce zinc absorption | Space apart by several hours
3. Magnesium - Can compete for absorption when taken together | Take at different times

Drug Interactions:
1. Bisphosphonates (Fosamax, Boniva) - Calcium reduces absorption of these osteoporosis drugs | Take bisphosphonates first thing in morning, calcium later in day | Severity: Moderate
2. Thyroid medications (Synthroid, levothyroxine) - Calcium reduces thyroid hormone absorption | Take thyroid medication 4 hours apart from calcium | Severity: Moderate
3. Tetracycline and quinolone antibiotics - Calcium binds to these antibiotics reducing effectiveness | Take antibiotics 2 hours before or 4-6 hours after calcium | Severity: Moderate
4. Corticosteroids - Long-term steroid use depletes calcium and increases osteoporosis risk | May need increased calcium and vitamin D supplementation | Severity: Moderate
5. Calcium channel blockers - High calcium intake may theoretically reduce drug effectiveness | Consult prescriber | Severity: Mild
6. Digoxin - Hypercalcemia can increase digoxin toxicity | Monitor calcium levels | Severity: Moderate

Food Interactions:
- Caffeine - Increases calcium excretion in urine; limit to moderate intake
- High-sodium foods - Excess salt increases calcium loss through urine
- Alcohol - Interferes with calcium absorption and bone health
- Oxalate-rich foods (raw spinach, rhubarb) - Bind calcium and reduce absorption
- Wheat bran/phytates - Can reduce calcium absorption
- Carbonated soft drinks - High phosphate content may displace calcium from bones

Safety Information

Contraindications:
- Hypercalcemia (elevated blood calcium)
- Hyperparathyroidism
- History of calcium-containing kidney stones (use calcium citrate if supplementing)
- Severe kidney disease
- Sarcoidosis or other granulomatous diseases

Side Effects:
- Constipation (common, especially with calcium carbonate)
- Gas and bloating
- Nausea (more common if taken on empty stomach)
- Kidney stones (at high doses, particularly calcium carbonate)
- Rare: Hypercalcemia symptoms (confusion, fatigue, excessive thirst)

Long-Term Use:
- Generally safe at recommended doses (1,000-1,200 mg/day)
- Some studies suggest doses exceeding 1,000-1,400 mg/day from supplements may increase cardiovascular risk; dietary calcium does not carry this risk
- Regular monitoring recommended for those taking high doses
- Kidney function should be monitored in at-risk individuals
- No cycling necessary at standard doses

Special Precautions:
- Pregnancy: Safe and recommended at standard doses (1,000-1,300 mg daily)
- Breastfeeding: Safe at standard doses
- Elderly: Calcium citrate preferred due to reduced stomach acid production
- Surgery: No specific precautions needed
- Avoid supplements containing bone meal, oyster shell, or dolomite as they may contain lead or other heavy metals

Primary Uses At-a-Glance

Primary: Bone health, osteoporosis prevention, bone density maintenance, fracture prevention, teeth health

Secondary: PMS symptom relief, blood pressure support, muscle function, nerve transmission, colon health support

Sources

Local Library:
- Moyad, Mark - The Supplement Handbook
- Brewer, Sarah - TDT Encyclopedia of Vitamins
- Moline, Peg - The Doctors Book of Natural Health Remedies
- Wilen, Lydia - Healing Remedies
- Weil, Andrew - Eating Well for Optimum Health
- Stewart, Martha - Living the Good Long Life
- Gaby, Alan R. - A-Z Guide to Drug-Herb-Vitamin Interactions
- Soule, Deb - The Woman's Handbook of Healing Herbs

General Knowledge:
- National Osteoporosis Foundation guidelines
- Institute of Medicine calcium recommendations
- Women's Health Initiative study data