Calcium
Calcium helps build and strengthen bones and teeth. As it's the major mineral found in bone, it is fundamental to bone health at all stages of life.
Calcium also plays a role in the following:
- Neuromuscular transmission
- Muscle contraction
- Blood pressure regulation
- Activation of many enzyme systems involved in regulating the metabolism
- Hormone secretion
- Blood clotting
Calcium is stored in bone mass and released in our body as needed. If we don't get enough calcium in our diet, our body draws on its reserve, which weakens our bones and increases our risk of fracture.
An adequate dietary calcium intake in early childhood is believed to promote good bone health and reduce the risk of developing osteoporosis and other chronic diseases.
Calcium intake is particularly important in the following life stages:
- In childhood, to maximize calcium retention during this period of rapid bone growth
- In adolescence, to foster the development of bone mass
- During pregnancy, to optimize the baby's bone health and prevent calcium deficiency, which can have irreversible consequences
The elderly also have higher calcium requirements, as the body becomes less efficient at absorbing calcium and loses more bone mass with age.
The long-term use of certain corticosteroid treatments (e.g., prednisone) has been associated with accelerated bone loss. Patients following this type of treatment may need to pay special attention to their calcium intake.
Interestingly, a diet rich in calcium and vitamin D may relieve PMS symptoms and protect against or slow colorectal cancer.
Dietary sources
The following foods are excellent sources of calcium:
- Dairy products such as Parmesan cheese, cheddar cheese, and cow's milk
- Regular tofu made with calcium sulfate
- Whole sesame seeds
- Fortified plant-based beverages
- Fresh soybeans (edamame)
Grain products, fruits, vegetables, and some legumes are also good sources of calcium.
Cow's milk, some plant-based beverages, and fortified yogurts contain vitamin D, which promotes the absorption and use of calcium.
Approximate calcium content
| Food | Portion | Content |
|---|---|---|
| Parmesan cheese | 50 g | 590 mg |
| Regular tofu prepared with calcium sulfate | 150 g | 520 mg |
| Sesame seeds, whole | 60 mL | 375 mg |
| Cheddar cheese | 50 g | 330 mg |
| Soy beverage, fortified | 250 mL | 320 mg |
| Cow's milk | 250 mL | 310 mg |
| Canned sardines, with bones | 75 g | 280 mg |
| Soybeans, fresh (edamame), raw | 125 mL | 270 mg |
| Food | Portion | Content |
|---|---|---|
| Cottage cheese, 2% fat | 250 mL | 270 mg |
| Plain yogurt, 1% to 2% fat | 175 g | 270 mg |
| Canned pink salmon, with bones | 75 g | 210 mg |
| Greek yogurt, plain, fat-free | 175 mL | 190 mg |
| Rhubarb, cooked | 125 mL | 180 mg |
| Blackstrap molasses* | 15 mL | 165 mg |
| Orange juice, enriched with calcium | 125 mL | 150 mg |
| Almonds, dry roasted | 60 mL | 90 mg |
*Blackstrap molasses is different from the fancy molasses generally used in baking. It has a darker colour, a more robust and bittersweet flavour, and higher nutritional value than other types of molasses. It is available in some grocery stores and health food markets.
It should be noted that certain foods rich in oxalates (a type of compound found in certain plants) reduce calcium absorption. The following vegetables are high in oxalates:
- Rhubarb
- Spinach
- Beets
Furthermore, a high salt intake, physical inactivity, and excessive caffeine consumption may increase the urinary excretion of calcium.
Recommended daily allowance (RDA)
The RDA for calcium is the daily calcium intake required to meet the needs of most healthy individuals.
Calcium Requirements
| Age | Men | Women |
|---|---|---|
| 1-3 years old | 700 mg | 700 mg |
| 4-8 years old | 1000 mg | 1000 mg |
| 9-13 years old | 1300 mg | 1300 mg |
| 14-18 years old | 1300 mg | 1300 mg |
| 19-50 years old | 1000 mg | 1000 mg |
| Age | Men | Women |
|---|---|---|
| 51-70 years old | 1000 mg* | 1200 mg |
| > 70 years old | 1200 mg | 1200 mg |
| Pregnancy and breastfeeding < 18 years> | 1300 mg | |
| Pregnancy and breastfeeding ≥ 18 years old | 1000 mg |
*Osteoporosis Canada recommends that men over 50 get 1200 mg of elemental calcium daily.
Deficiency
Dietary calcium deficiency can cause stunted growth in children and decreased bone mass (i.e., osteoporosis) in adults.
Calcium levels in the blood can be low without causing any symptoms. However, calcium levels that are abnormally low for a prolonged period may result in the following:
- Cramps
- Muscle stiffness
- Muscle pain
- Confusion
- Depression
- Tingling in the feet, hands, and lips
Certain health conditions combined with severe dietary calcium deficiency could lead to these types of symptoms.
Toxicity
Calcium levels in the blood can be abnormally high without causing any symptoms. If symptoms do develop, they may include the following:
- Digestive problems, such as gastric irritation and constipation
- Excessive urination that can lead to dehydration
- Excessive thirst
- Kidney stones
High amounts of calcium can also block the absorption of other minerals, like iron, zinc, and manganese. In the most severe cases, excess calcium in the blood can lead to neurological problems, confusion, and coma.
A balanced diet that includes calcium-rich foods cannot lead to abnormally high levels in the blood. Certain health conditions combined with excessive calcium intake could lead to the above-mentioned symptoms.
Supplements
Although it is possible to get enough calcium from food alone, some people need to supplement their dietary intake.
Vitamin D promotes the absorption and use of calcium, which is why it is often combined with calcium in supplements.
Some calcium supplements should be taken with food, while others should be taken on an empty stomach. Talk to your pharmacist to find out which supplement is right for you.
Always watch your diet:
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The patient information leaflets are provided by Vigilance Santé Inc. This content is for information purposes only and does not in any manner whatsoever replace the opinion or advice of your health care professional. Always consult a health care professional before making a decision about your medication or treatment.