Symbol – Ca
Atomic Number – 20
Melting point – 1115k
Boiling point – 1757k
It is one of the most abundant minerals found in nature.
Most common calcium compound on earth is calcium carbonate found in lime stones.
Bone is a dynamic tissue which is remodeled throughout life. Bone cells called osteoclasts →dissolving or resorbing bone. Bone cells called osteoblasts →synthesize new bone. During normal growth, bone formation exceeds bone resorption.
Its importance in human body is indispensable –
- It helps in physiological and biochemical processes of organisms and cells
- It is the building block of body and helps in providing structural strength to body by formation of healthy bones and teeth
- It acts as a co-factors in many enzymes
- It helps in synthesis and function of blood cells
- It helps in contraction of all muscle cell types
- It helps in signal transmission via nerve conduction
- It helps in blood clotting. The binding of calcium ions is required for activation of the seven ‘vitamin K dependent’ clotting factors in coagulation cascade.
Parathyroid hormone and vitamin D promote the bone formation by allowing and enhancing the deposition of calcium ions (Ca2+), allowing rapid bone turnover without affecting bone mass or mineral content.
Food sources –
Highest sources of calcium → are found in dairy products like milk, cheese, yogurt, buttermilk.
Apart from diary products other sources of calcium are – almonds, sunflower seeds, beans, sesame seeds, figs, dandelion leaves, lentils, chia seeds, fortified breakfast cereals, leafy greens (kale, broccoli, sweet potato), seafood (sardines, salmon), seaweeds
1 year to 3 years —– 700mg/day
4 years to 8 years —-1000mg/day
9 years to 18 years —- 1300mg/day
19 years to 50 years —- 1000mg/day (includes pregnancy and lactation)
51 years and ahead only for females —- 1200mg/day
Normal calcium levels in blood –
Adults – 8.8 to 10.4mg/dL
Diagnosis of calcium can be made through blood test.
In osteoporosis, diagnosis can be made by Bone Mineral Density Scan (BMD).
Low calcium levels (hypocalcemia) –
Is caused due to –
- Hypoparathyroidism – most common
- Vitamin D deficiency – most common
- Kidney failure
- Calcium channel blocker
- Magnesium deficiency
- High sodium intake
- As a complication of pancreatitis
- Chelating agents such as EDTA
- Certain cancers
Hypocalcemia can lead to –
In short term period –
- Muscle cramps
- Confusion, forcefulness
- Tingling sensation in body parts
- Weak and brittle nails
- Premenstrual syndrome (PMS)
In long term period, it can cause –
- Chronic joint and muscle pain
- Dental changes
Neonatal hypocalcemia can include –
- Apnoea or slowed breathing
- Poor feeding
- Tachycardia or faster than normal heartbeat
High calcium levels (Hypercalcemia) –
Is caused due to –
- Hyper active parathyroid glands
- Certain medical disorders (tuberculosis, cancers, thyroid, chronic kidney disease, adrenal gland’s disease)
- Taking too much calcium and vitamin D supplements
- Lithium medications can overstimulate parathyroid glands
Short term effects of hypercalcemia –
- Excessive thirst
- Frequent urination
- Stomach upset
- Nausea, vomiting
- Bone pain
- Muscle weakness
Long term effects of hypercalcemia –
- Kidney stones
- Poor bone health
- Abnormal heart and brain function
- Kidney failure and coma
Interesting facts about calcium –
- Calcium intake can cause bloating and gas
- Calcium works together with magnesium. The ratio is 2:1; calcium:magnesium.
- Lack of calcium causes osteoporosis (A disease where bones are extremely porous and are subject to fracture. The healing is also delayed especially after menopause)
- Vegetables containing oxalic acid decrease absorption of calcium in body
- Vitamin D helps your body use calcium effectively
- Taking more calcium supplements in large doses can lead to kidney stones
- Medications can interfere in calcium absorption. Certain examples are diuretics (furosemide), beta blockers (atenolol), antibiotics (rifampicin), digoxin, antacids containing aluminium.
- ‘Hungry bone syndrome’ can develop after surgery of hyperparathyroidism.
- Smoking can reduce the growth of new bone and decrease estrogen levels in women
- Alcohol can reduce absorption of calcium levels in body
- Walking promotes healthy bones and strengthen muscles
- Hyperthyroidism, hyperparathyroidism, cushing syndrome, rheumatic arthritis, ankylosing spondylitis, coeliac disease can increase risk of hypocalcemia and osteoporosis
- Water can play an important role in hypercalcemia by removing excess calcium through urine
- Removal of thyroid gland can cause drop in Calcitonin hormone (hormone which regulates calcium levels in body and involved in bone building)
- Bones stores calcium. So, when the calcium level in blood drops, bones compensate it by providing calcium through bones and hence eventually becomes brittle and prone to injury.
- Data from research studies proves that calcium supplements in pregnancy can reduce the risk of high BP and pre-eclampsia
- 99% of calcium is found in bones and teeth
- High calcium levels can cause prostate cancer in some people