Calcium is one of the most important minerals involved in large number of vital body functions.

Calcium is one of the most important minerals involved in large number of vital body functions. The name calcium is derived from Latin word calas means lime. It ranks fifth in the order of abundance of elements in earth’s crust. It does not occur free in nature but in the form of carbonates and sulphates. As carbonate, it occurs as lime stone, chalk, marble and as sulphate in gypsum form.

99% of the body’s calcium is in the bones and teeth and 1% in the blood and other tissues to perform the functions. The calcium in the blood and tissues and that in the skeleton are in equilibrium. The calcium of the bone can be drawn up  to make up deficiency of blood calcium and when the deficit is made up, it is redeposited in the bone to maintain its density.

Bone density refers to how much calcium and other minerals are present in the section of bone. It increases during first 25 to 30 years of life and then gradually decreases with age when the rate of new bone formation and breakdown happens at the same rate. So, adequate calcium intake is required to maximize peak bone mass and limit bone loss later in life otherwise the bones may become brittle and fragile and can break easily.

Functions
1.    Combines with phosphorus mineral, calcium constitutes hydroxyapatite, responsible for bone strength and its resistance to decay.
2.    Helps normal contraction of muscles and heart.
3.    Helps blood to clot when required.
4.    Assists nerves to carry messages between brain and rest of the body.
5.    Helps normal contraction and relaxation of blood vessels.
Absorption of Calcium
Solubility
Calcium must be soluble in the acid medium of stomach. Gastric acid causes ionisation of calcium and increases its absorption.
Small Intestines
Healthy lining of small intestine favours the absorption of ingested calcium.
Vitamin D
Vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium concentration to enable normal bone growth.
Active life style
Promotes bone health by increasing calcium density in bones.
Protein
Researches indicate that calcium absorption may be positively associated with protein intake.
Caffeine
It appears to have a slight negative effect on calcium absorption.
Alcohol
Consumption of alcohol is a risk factor for bone loss.
Plant food
The presence of oxalic and phytic acid in some plant foods decreases the bioavaiability of calcium. Foods rich in oxalic acid are spinach, rhubarb, okra and beans. Food high in phytic acid include grains and nuts.
Calcium is more bioavailable from plants such as broccoli, sweet potatoes and kale.
Phytic acid present in food can be destroyed to some extent by cooking and digestion. Soya bean is an exception amongst plant foods. Soya beans contain high quantities of both oxalates and phytates yet provide absorbable source of calcium.
Hormones
Parathyroid hormone maintains the level of calcium in the blood and stimulates bone formation. Calcitonin hormone produced from Vitamin D, increases intestinal absorption of calcium and phosphorus. It maintains normal blood calcium level. Estrogen, another important hormone, promotes intestinal calcium absorption. 
CALCIUM DEFICIENCY
Calcium deficiency is usually a result of vitamin D deficiency, impaired parathyroid hormone production, impaired bone resorption of calcium, critical illness or use of medicines like antacids. It can be asymptomatic when it is mild.
Symptoms
•    Seizures
•    Depression
•    Poor appetite
•    Heart problems
•    Risk of fractures
•    Muscular spasms
•    Increased neuro muscular irritability like numbness, tingling in hands and feet
RISK GROUP
Postmenopausal women
Decrease in oestrogen after menopause reduces calcium absorption and increases urine excretion.
There is average 1% loss of bone mineral density per year after menopause.
Diet deficient of dairy products
People with lactose intolerance and those who do not take dairy products have a higher risk of inadequate calcium intake.
Toxicity
The upper limit of calcium intake is 3500 mg daily. If taken more than this, there is increased risk of kidney stones, constipation, cancer and heart diseases. 
Daily Calcium Requirement
Age    mg per day
0-6 months    200 mg
06-12 months    260 mg
1-3 years    700 mg
4-8 years    1,000 mg
19-15 years    1,000 mg
51-70 years (M)     1,000 mg
51-70 years (F)    1,200 mg
71 and older    1,200 mg
Calcium Rich Drugs in Ayurveda
In Ayurveda, there is vast mention of calcium supplements from natural sources which are classified under Shuklavarga Dravyas. Their sources are Shankh i.e. snail shells, Praval i.e. coral, Mukta i.e. pearls, Shukti i.e. oyster shells. All of these contain high quality calcium as calcium carbonate and other essential minerals too. They work best as calcium supplements in osteoporosis, dental caries, arthritis and gastric ulcers. Studies have found that marine derived calcium has certain advantages over other calcium supplements. They  have the potential to increase bone turnover and aid in preventing injuries and repairing damaged bones.
 

Other calcium supplements
1.    Calcium citrate
2.    Calcium gluconate
3.    Calcium lactate
Some calcium supplements contain vitamin D for its better absorption.
Food high in Calcium
•    Dairy products such as milk, cheese, yogurt.
•    Vegetables like broccoli, kale, collard
•    Calcium fortified breads, cereals, soy products
•    Vitamin D fortified milk
•    Seeds like sesame, poppy.
BMD test (Bone Mineral Density test)
It measures how much calcium and other minerals are present in a part of our bone. The more the minerals, the healthier is the bone. The x-rays are used for the measurement. The test is recommended for those who have recurrent fractures, all women over age of 60, post menopause, weight loss, back pain. The test is painless and quick. There are two types of scans done:

Central DXA (Dual Energy Xray Absorptiometry)
X-ray machine scans hip and spine. 
Peripheral DXA
Scanning of bones of forearms, wrist and finger is done.
Result
For the result we will get a T-score.
It shows how much higher or lower our bone density is than that of a healthy person. The lower the score, the weaker our bones
T score of -1.0 or above = normal bone density
T score between -1.0 and -2.5 = low bone density
T score of -25 or lower = severe bone loss

In conclusion, we can say that calcium is essential for building our bones and maintaining their health. It also helps to manage blood pressure and keeps the heart normal. Our body does not produce it; so to meets its requirement for body functions, we have to rely on diet rich in calcium and vitamin D, physical activity and good exposure to sunlight

*Associate Professor
Department of Shalakya Tantra,
Mob: 7973197093, drrajnidav@gmail.com
**Assistant Professor
Department of Panchkarma,
Mob.: 80958-21236
Dayanand Ayurvedic College, Jalandhar.