What is the Role of Calcium (Ca) in Good Nutrition?



INDEX

What are the Key Functions of Calcium?

What are the Best Sources of Ca?

Who would benefit from Ca supplementation?

When should Ca supplementation be used?

How much Ca is usually taken?

What are the side effects of using Ca supplementation?




A range of foods from milk and cheese, to sardines (eaten with their bones) and dark green leafy vegetables, contain calcium (Ca). It is a vital component of bones and teeth, which contain some 99 percent of the body's total Ca. The other 1 percent plays an equally important role in the body, both in cell structure and function, as well as in the blood, where it aids clotting.

Because of the body's natural regulatory systems, excessive Ca in the blood occurs rarely and only as a result of disease or through overuse of vitamin D supplements. If, however, the body needs more Ca it withdraws it from the bones.

Ca is also needed for the smooth functioning of nerves and muscles and supplements are used to treat muscle cramps, and problems of the back and bones related to aging, such as arthritis, rheumatism and osteoporosis (the loss of bony tissue that results in brittle bones, particularly prevalent among post-menopausalwomen).

A Ca-deficiency often results from a lack of vitamin D and can lead to rickets in children with the typical symptoms of bow legs, knock-knees and pigeon chests caused by softening of the bones. In adults, it can cause osteomalacia, characterized by aching bones, muscle spasms and curvature of the spine.

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What are the Key Functions of Ca?



It is a vital component of bones and teeth, which contain some 99 percent of the body's total Ca. The other 1 percent plays an equally important role in the body, both in cell structure and function, as well as in the blood, where it aids clotting.

As we grow, our bodies continually remove and replace small amounts of Ca from our bones. If more Ca is removed than is replaced, bones become weaker and have a greater chance of breaking.

When you get enough calcium from the foods you eat and drink, your body doesn’t have to subtract the calcium from your bones. Getting enough Ca from an early age can help prevent osteoporosis, a condition that makes bones weak and more likely to break. The importance of Ca for preventing osteoporosis is probably its most well-known role.

For both young children and adults, Ca is also needed to grow and develop teeth and it also help protect teeth against tooth decay.

Adequate Ca intake is protective against lead toxicity because calcium inhibits intestinal absorption of lead.

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What are the Best sources of Ca?

Most dietary calcium (Ca) comes from dairy products. Low-fat and fat-free milk and other dairy products are great sources of Ca because of they have so much of it.

Low-fat and fat-free milk and dairy products are great sources of Ca because of the following reasons:


Other good sources of Ca, including:

  • Dark green, leafy vegetables, such as spinach, broccoli, and bok choy
  • Foods with Ca added, such as calcium-fortified tofu, orange juice, soy beverages, and breakfast cereals or breads
  • Ca is found in sardines and canned salmon.

Experts agree and recommend obtaining as much calcium as possible from natural foods because the Ca in foods is accompanied by other important nutrients that assist the body in utilizing Ca.

However, calcium supplements may be necessary for those who have difficulty consuming enough Ca from foods. No multivitamin/multi mineral tablet contains 100% of the recommended daily value (DV) for Ca.

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Who would benefit from Calcium supplementation?



A condition called rickets in children and osteomalacia in adults are caused by a severe deficiency of either calcium (Ca) or Vitamin D.

Vitamin D is required for Ca-absorption, people with conditions such as pancreatic insufficiency, causing vitamin D deficiency may develop a deficiency of Ca as well.

People not eating meat products - Vegans (pure vegetarians), people with dark skin, those who live in northern climates, and people who stay indoors almost all the time are more likely to be vitamin D deficient than are other people.

Most people eat well below the recommended amount of Ca. White and Asian women are at risk of osteoporosis due to a lack of dietary Ca.

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When should Ca supplementation be used?



Calcium has been used in connection with the following conditions:

Gestational hypertension Lactose intolerance (for preventing deficiency if dairy products are avoided only)
Osteoporosis Preeclampsia (for deficiency)
Premenstrual syndrome Rickets
Celiac disease (for deficiency only) High blood pressure
High cholesterol High triglycerides
Pregnancy and postpartum support Weight loss

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How much Calcium is usually taken?



The Food and Nutrition Board of the Institute of Medicine set the tolerable upper level of intake for Ca in adults at 2,500 milligrams (mg) of Ca/day.

Men

There is a lack of agreement among researchers trying to determine the relationship between Ca and prostate cancer, which suggests complex interactions among the risk factors for prostate cancer and it also reflect the difficulties associated with assessing Ca intake in free living humans.

Because of this, it is reasonable for men to consume a combined (diet and supplements) total of 1,000 to 1,200 mg/day of Ca, which is the adequate intake level recommended by the Food and Nutrition Board of the Institute of Medicine.

Children and adolescents (9-18 years)

Children and adolescents should consume a combined total (diet plus supplements) of 1,300 mg/day of Ca for maximal peak bone mass.

Adults (ages 19-50 years)

Your skeleton normally continues to accumulate bone until the about the age of 30 when peak bone mass is attained. Adult men and women, 50 years of age and younger, should consume a combined total (diet plus supplements) of 1,000 mg/day of Ca to promote maximal peak bone mass and to minimize bone loss later in life.

Older adults (51 years and older)

Older men and postmenopausal women should consume a combined total (diet plus supplements) of 1,200 mg/day of Ca to minimize bone loss. To ensure adequate Ca absorption a multivitamin/multi mineral supplement can be taken that contains at least 10 mcg (400 IU)/day of vitamin D3. (see Vitamin D).

Pregnant and breast-feeding women

Pregnant and breastfeeding adults (19 years and older) should consume a combined total (diet plus supplements) of 1,000 mg/day of Ca.

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What are the side effects of using Calcium supplementation?



Iron absorption decreases in the presence of Ca from iron sources such as most supplements and food sources other than meat.

Low Ca intakes could result in hormonal and metabolic changes that increase the tendency of fat cells to accumulate fat but trials showed that higher dietary Ca intakes were associated with weight loss. Results however are not conclusive.

Abnormal heart rhythms in people taking digitalis (digoxin) for heart failure were linked to high doses of supplemental calcium.

Some research studies have found a correlation between high dosages of Ca-usage and the development of prostrate cancer. But other studies have not found the same correlation. It is therefore recommended to stay within the Food and Nutrition Board of the Institute of Medicine upper tolerance level.

The risk of developing kidney stones in women taking high dosages of supplemental Ca was found to be 20% higher than in those who did not take supplements. This could be because abnormally elevated blood Ca (hypocalcaemia) resulting from the over consumption of Ca has never been documented to occur from foods but only from Ca-supplements.

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