Calcium is the most abundant mineral in the human body and has several important functions. Calcium is the top macro mineral when it comes to your bones. This mineral helps build strong bones, so you can do everything from standing up straight to scoring that winning goal. Calcium is a primary structural constituent of the skeleton, but it is also widely distributed in soft tissue where it is involved in neuromuscular, enzymatic, hormonal, and other metabolic activity.

Calcium absorption is dependent upon the calcium needs of the body, the foods eaten, and the amount of calcium in the foods eaten. Vitamin D from diet or exposure to the ultraviolet light of the sun increases calcium absorption. Calcium absorption tends to decrease with increased age for both men and women. More than 99% of total body calcium is stored in the bones and teeth where it functions to support their structure. The remaining 1% is found throughout the body in blood, muscle, and the fluid between cells. Because of its biological importance, calcium levels are carefully controlled in various compartments of the body. The three major regulators of blood calcium are parathyroid hormone (PTH), vitamin D, and calcitonin.

Calcium Stats
Atomic Number : 20 Atomic Radius : 197.3 pm
Atomic Symbol : Ca Melting Point : 842 0C
Atomic Weight : 40.08 Boiling Point : 1484 0C
Electron Configuration : [Ar]4s2 Oxidation States : 2
Functionality of calcium:

It helps in building of strong bones, healthy teeth, for chomping on tasty food. Because the body cannot manufacture calcium, you must eat calcium in your daily diet to replace the amounts that are constantly lost. Calcium is also used in muscle contraction, blood clotting, and maintenance of cell membranes. Long-term calcium deficiency can lead to osteoporosis, in which the bone deteriorates and there is an increased risk of fractures. Calcium has also been found to assist in the production of lymphatic fluids. Just 1% of the total body pool of calcium is utilized to support nerve transmission, muscle contraction (including normal heart rhythm), blood clotting, and regulation of enzyme and hormone activities. Membrane calcium transport systems are involved in regulation of cellular osmolarity and peripheral vascular resistance. Additionally, this mineral assists in transport of nutrients and other substances across cell membranes and is required for binding of intrinsic factor to ilea receptors for absorption of vitamin B12.

Deficiency Diseases of calcium: Arthritis, High Blood Pressure, Osteoporosis

Overdose Disease of calcium: Constipation and lack of appetite

Deficiency Symptoms of calcium:

Because bone stores of calcium can be used to maintain adequate blood calcium levels, short-term dietary deficiency of calcium generally does not result in significantly low blood calcium levels. But, over the long term, dietary deficiency eventually depletes bone stores, rendering the bones weak and prone to fracture. The symptoms of calcium deficiency are:

  • Bowlegs, Pigeon Breast, and Knock-knees of children
  • Cramp pains in legs
  • Delay in sitting up, Crawling and Walking of babies
  • Heart becomes irregular
  • Nerves become extremely irritable
  • Poor sleep disorder
  • Weakness in the bones
Rich Sources of calcium:
  • Dairy Products, such as Milk, Cheese, and Yogurt
  • Canned Salmon and Sardines with Bones
  • Leafy Green Vegetables, such as Broccoli, Spinach
  • Calcium-Fortified foods - from Orange juice to Cereals and Crackers
  • Ice Cream, Kale, Oysters, Ricotta

Individuals two years and older should eat 2-3 servings of dairy products per day. A serving is equal to:

  • 1 cup (8 fl oz) of milk

  • 8 oz of yogurt

  • 1.5 oz of natural cheese

  • 2.0 oz of processed cheese

Although dairy products are the main source of calcium in the diet, other foods also contribute to overall calcium intake. A person may have to eat several servings of certain foods such as spinach to obtain the same amount of calcium in one cup of milk, which is not only calcium-rich but also contains calcium in an easily absorbable form.

Calcium is Important for:
  • Formation of bones and teeth
  • Coagulation of blood
  • Contraction of muscles, Cardiac action, Milk production
  • transformation of light to electrical impulses in the retina
  • Young mothers during pregnancy and the nursing period
  • Children and young people for rapid growth of bones
Best Suitable Composition:

Calcium, Magnesium, Vitamin D, Phosphorus, Soy-based foods and Fluoride compose the major nutrients that strengthen bone. A deficiency of any of these may produce a serious disturbance in the framework of the body.

Applications or Uses of Calcium:
Some of the applications or uses of calcium are as follows:
  • Calcium is used in the extraction of other metals, such as uranium, zirconium, and thorium as a reducing agent:
  • Calcium is used for various ferrous and nonferrous alloys as a deoxidizer, desulfurizer, or decarbonizer.
  • Calcium is used in the production of aluminium, beryllium, copper, lead, and magnesium alloys as an alloying agent
  • Calcium is also used in the making of cements and mortars to be used in construction.
How to retain calcium in healthy food?
Calcium is lost in cooking some foods even under the best conditions. To retain calcium:
  • Cook foods in a minimal amount of water.
  • Cook for the shortest possible time.
  • Some foods, such as orange juice, bread, and ready-to-eat cereals, are not normally good sources of calcium but may have had calcium added. Most instant-prepared cereals are fortified with calcium.
  • The serving sizes used on the list of good sources is only estimates of the amounts of food you might eat. The amount of nutrient in a serving depends on the weight of the serving. For example, a cup of a cooked vegetable contains more calcium than a cup of the same vegetable served raw, because a serving of the cooked vegetable weighs more. Therefore, the cooked vegetable may appear on the list while the raw form does not.
  • Use low fat or fat free milk instead of water in recipes such as pancakes, mashed potatoes, pudding and instant, hot breakfast cereals.
  • Blend a fruit smoothie made with low fat or fat free yogurt for a great breakfast.
  • Sprinkle grated low fat or fat free cheese on salad, soup or pasta.
  • Choose low fat or fat free milk instead of carbonated soft drinks.
  • Serve raw fruits and vegetables with a low fat or fat free yogurt based dip.
  • Create a vegetable stir-fry and toss in diced calcium-set tofu.
  • Enjoy a parfait with fruit and low fat or fat free yogurt.
  • Complement your diet with calcium-fortified foods such as certain cereals, orange juice and soy beverages.
Recommended Daily Intake:
The Recommended Daily Intakes (RDI) for calcium is shown in the table given below:

Calcium Requirements
 Life Stage Calcium mg/day
0-6 months 210
7-12 months 270
1-3 years 500
4-8 years 800
9-13 years 1300
14-18 years 1300
19-30 years 1000
31-50 years 1000
51-70 years 1200
>70 years 1200
9-13 years 1300
14-18 years 1300
19-30 years 1000
31-50 years 1000
51-70 years 1200
>70 years 1200
< 18 years 1300
19-30 years 1000
31-50 years 1000
< 18 years 1300
19-30 years 1000
31-50 years 1000

Calcium is one of the most important macronutrients for the body's growth and function. Sufficient amounts are important in preventing many diseases. Calcium levels are tightly controlled by a complex interaction of hormones and vitamins. Dietary requirements vary throughout life and are greatest during periods of growth and pregnancy. However, recent reports suggest that many people do not get sufficient amounts of calcium in their diet. Various calcium supplements are available when dietary intake is inadequate.

Who needs extra calcium to prevent a deficiency?
  • Menopausal Woman
  • Menopausal Woman often leads to increases in bone loss with the most rapid rates of bone loss occurring during the first five years after menopause. Drop in estrogen production after menopause result in increased bone resorption, and decreased calcium absorption.

    Estrogen therapy works to restore postmenopausal bone remodeling levels back to those of pre-menopause, leading to a lower rate of bone loss. Estrogen appears to interact with supplemental calcium by increasing calcium absorption in the gut. However, including adequate amounts of calcium in the diet may help slow the rate of bone loss for all women.

  • Amenorrheic Women and the Female Athlete triad
  • Amenorrhea is the condition when menstrual periods stop or fail to initiate in women who are of childbearing age. Secondary amenorrhea is the absence of three or more consecutive menstrual cycles after menarche occurs (first menstrual period). The secondary type of amenorrhea can be induced by exercise in athletes and is referred to as "athletic amenorrhea". Potential causes of athletic amenorrhea include low body weight and low percent body fat, rapid weight loss, sudden onset of vigorous exercise, disordered eating and stress.

    The condition "female athlete triad" refers to the combination of disordered eating, amenorrhea, and osteoporosis. Exercise-induced amenorrhea has been shown to result in decreases in bone mass. In female athletes, low bone mineral density, menstrual irregularities, dietary factors, and a history of prior stress fractures are associated with an increased risk of future stress fractures. Thus, it is important for amenorrheic women to maintain the recommended Adequate Intake for calcium.

  • Lactose Intolerant Individuals
  • Lactose mal-digestion (or "lactase non-persistence") describes the inability of an individual to completely digest lactose, the naturally occurring sugar in milk. Lactose intolerance refers to the symptoms that occur when the amount of lactose exceeds the ability of an individual's digestive tract to break down lactose.

    Symptoms of lactose intolerance include bloating, flatulence, and diarrhea after consuming large amounts of lactose (such as the amount in 1 quart of milk). Lactose maldigesters may be at risk for calcium deficiency, not due to an inability to absorb calcium, but rather from the avoidance of dairy products. Symptoms of lactose intolerance vary from individual to individual depending on the amount of lactose consumed, history of previous consumption of foods with lactose and the type of meal with which the lactose is consumed. Drinking milk with a meal helps reduce symptoms of lactose intolerance substantially.

  • Vegetarians
  • There are several types of vegetarian eating practices. Individuals may choose to include some animal products or no animal products in their diet. Calcium absorption may be reduced in vegetarians because they eat more plant foods containing oxalic and phytic acids, compounds which interfere with calcium absorption. However, vegetarian diets that contain less protein may reduce calcium excretion. Yet, vegans may be at increased risk for inadequate intake of calcium because of their lack of consumption of dairy products. Therefore, it is important for vegans to include adequate amounts of non-dairy sources of calcium in their daily diet

Calcium Supplements

Calcium supplements are taken by individuals who are unable to get enough calcium in their regular diet or who have a need for more calcium. They are used to prevent or treat several conditions that may cause hypocalcemia (not enough calcium in the blood). The body needs calcium to make strong bones. Calcium is also needed for the heart, muscles, and nervous system to work properly.

Pregnant women, nursing mothers, children, and adolescents may need more calcium than they normally get from eating calcium-rich foods. Adult women may take calcium supplements to help prevent a bone disease called osteoporosis. Osteoporosis, which causes thin, porous, easily broken bones, may occur in women after menopause, but may sometimes occur in elderly men also. Other bone diseases in children and adults are also treated with calcium supplements.

Vitamin D helps prevent calcium loss from your bones. It is sometimes called "the sunshine vitamin" because it is made in your skin when you are exposed to sunlight. If you get outside in the sunlight every day for 15 to 30 minutes, you should get all the vitamin D you need. However, in northern locations in winter, the sunlight may be too weak to make vitamin D in the skin. Vitamin D may also be obtained from your diet or from multivitamin preparations. Most milk is fortified with vitamin D.