Calcium is a nutrient that all living organisms need, this includes humans. Calcium is the most abundant mineral in the body and is known for its vital role in bone health: 99% of the body’s calcium is found in bones and teeth. (3)
However, this is not its only role. Calcium is also necessary to maintain healthy communication between the brain and other parts of the body. It plays a role in muscle movement and cardiovascular function. (1)
In addition to calcium, people also need vitamin D, as this vitamin helps the body absorb calcium. Vitamin D comes from fish oil, fortified dairy products, and exposure to sunlight.
This article looks at why the body needs calcium, what foods are high in calcium, what happens if the body doesn’t have enough, and the pros and cons of taking supplements.
Function of calcium in the body
Calcium serves several functions in the body. Some of them are described below:
1. Bone health
Calcium is essential for the development, growth and maintenance of bones. As children and adolescents grow, calcium contributes to their development.
Once a person stops growing, calcium continues to help maintain healthy bones and slow the loss of bone density, which is a natural part of the aging process.
Women who have already gone through menopause may lose bone density at a higher rate than men or younger people. This is why postmenopausal women are at higher risk of developing osteoporosis, and a doctor may recommend calcium supplements.
RECOMMENDED: Osteoporosis and menopause .
2. Muscle contraction
When a nerve stimulates a muscle, the body releases calcium. Calcium helps muscle proteins do the work of contraction.
In particular, in muscle fibers, calcium ions activate the chemical reaction between myosin and actin that releases energy and causes the muscle to contract.
Then the calcium ions quickly bind to the muscle reticulum and the muscle relaxes. This function is particularly important for the contraction and relaxation of the heart muscle.
Calcium relaxes the smooth muscle that surrounds the blood vessels of the heart. Several studies have indicated a possible link between high calcium intake and lower blood pressure. (1,2)
3. Blood clotting
Calcium plays a key role in blood clotting. The clotting process is complex and consists of several steps. These involve a variety of accessory molecules or cofactors, including calcium.
This important function of calcium ensures wound closure, and contributes to the maintenance of homeostasis.
4. Other functions
Calcium fulfills many other important roles in the body, although only 1% of the body’s calcium performs these functions.
- Several reviews and studies have endorsed that consuming an adequate calcium diet can help maintain a normal body weight and decrease the risk of obesity. (3,4)
- Other studies have documented the role of calcium through the consumption of dairy products in reducing the risk of type 2 diabetes. (5)
- An adequate amount of calcium could help improve cholesterol values (6)
- Adequate calcium intake is necessary for a lower risk of developing conditions that involve high blood pressure during pregnancy.
Foods rich in calcium
You can get enough calcium from food or drink. Dairy products usually come to mind when we think of foods rich in calcium, and this is correct.
Although some dark green vegetables like spinach also contain calcium. However, some also contain high levels of oxalic acid. Oxalic acid reduces the body’s ability to absorb calcium, to reduce this effect it is advisable to boil them.
Here is a list of examples of foods rich in calcium (6):
| Food | Portion | Calcium (mg) |
| Low fat yogurt | 1 cup | 314 |
| Milk (skim or whole) | 1 cup | 302 – 291 |
| Tofu | 100 g | 310 – 290 |
| Sardine with bone | 100 g | 200 – 250 |
| Queso cottage | 1 cup | 155 |
| Beans, cooked | 1 cup | 154 |
| Kale leaves | 100 g | 150 |
| Artichoke, boiled | 1 cup | 135 |
| Spinach, boiled | 1/2 cup | 122 |
| Walnuts | 100 g | 117 |
| Boneless sardines | 100 g | 50 mg |
How much calcium do you need per day?
The recommended amount of calcium varies based on a person’s age and gender. FAO recommends amounts of calcium per day according to the following table:
| Age | Recommended amount of calcium (per day) |
|---|---|
| Babies up to 6 months | 200 mg |
| Babies from 7 to 12 months | 260 mg |
| Children from 1 to 3 years | 700 mg |
| Children from 4 to 8 years old | 1,000 mg |
| Children from 9 to 13 years old | 1,300 mg |
| Adolescents from 14 to 18 years old | 1,300 mg |
| Adults from 19 to 50 years | 1,000 mg |
| Adult men ages 51 to 70 | 1,000 mg |
| Adult women ages 51 to 70 | 1,200 mg |
| Adults 71 and over | 1,200 mg |
| Pregnant or breastfeeding teens | 1,300 mg |
| Pregnant or breastfeeding adult women | 1,000 mg |
A doctor or nutritionist may recommend additional calcium for people who:
- have started menopause
- stop menstruating due to anorexia nervosa or excessive exercise
- have lactose intolerance or an allergy to cow’s milk
- follow a vegan diet
ABSTRACT
Calcium is essential for building and maintaining healthy bones and teeth. Among other functions, it can also help control blood pressure and ensure blood clotting.
It’s best to get enough calcium through food sources, such as dairy products, green leafy vegetables, and tofu. However, a doctor may recommend supplements for some people.
