Calcium is a vital mineral that plays numerous roles in the human body, particularly in bone health. Here's a summary of its benefits, risks, and sources:

Benefits of Calcium

1. Bone Health: Calcium is critical for forming and maintaining healthy bones and teeth. Adequate intake helps prevent osteoporosis¹².
2. Muscle Function: It aids in muscle contraction and relaxation³.
3. Blood Clotting: Essential for the blood-clotting process⁴.
4. Nerve Function: Calcium is involved in sending and receiving nerve signals⁴.
5. Hormonal Secretion: It assists in releasing hormones and other chemicals².

Sources of Calcium

1. Dairy Products: Milk, cheese, and yogurt are excellent sources. They contain a form of calcium that the body can easily absorb⁴.
2. Fortified Foods: Orange juice, soy milk, tofu, cereals, and bread fortified with calcium are good options⁵.
3. Leafy Greens: Vegetables like broccoli, kale, and Chinese cabbage. However, the bioavailability of calcium from these sources can be lower due to oxalic acid⁴.
4. Fish with Bones: Sardines and canned salmon with bones⁴.
5. Nuts and Seeds: Almonds, Brazil nuts, sunflower seeds, and tahini also provide calcium⁵.

Types of Calcium Supplements

1. Calcium Carbonate: Less expensive, should be taken with food, and is found in antacids like Tums⁶.
2. Calcium Citrate: More expensive but absorbs well on an empty or full stomach. It's the preferred choice for individuals with low stomach acid⁶.
3. Other Forms: Such as calcium gluconate and calcium lactate, which offer no significant advantages over the above⁶.

Risks of Excessive Calcium

1. Cardiovascular Disease: Some studies have suggested that excessive calcium intake may increase the risk of cardiovascular events⁷⁸.
2. Kidney Stones: High supplementation can raise the risk of kidney stones⁶.
3. Gastrointestinal Issues: It may cause constipation, bloating, and gas⁶.
4. Impaired Absorption: Excess calcium can interfere with the absorption of other minerals like iron, zinc, and magnesium⁶.

Considerations

1. Dosage: Adults should generally aim for around 1,000 to 1,200 mg/day, depending on age and gender⁶.
2. Combination with Vitamin D: Vitamin D is essential for calcium absorption⁸.
3. Gradual Increase: Start with smaller doses to reduce side effects and increase gradually⁶.

For those looking to supplement their calcium intake, it's crucial to balance the benefits and potential risks and consider getting advice from a healthcare provider.

Footnotes

1. PMC - Calcium supplementation ↩

2. MedlinePlus - Calcium in diet ↩ ↩²

3. PMC - Calcium homeostasis ↩

4. NIH - Calcium intake ↩ ↩² ↩³ ↩⁴ ↩⁵

5. Calcium supplements and health ↩ ↩²

6. NIH - Consumer factsheet on calcium ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

7. PubMed - Risks of calcium supplements ↩

8. The Risks and Benefits of Calcium Supplementation ↩ ↩²