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Calcium, its requirement, food sources and interesting facts

Symbol – Ca

Atomic Number – 20

Group -2

Period -4

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

Requirement –

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
  • Hyperphosphatemia
  • Magnesium deficiency
  • Osteomalacia
  • High sodium intake
  • As a complication of pancreatitis
  • Chelating agents such as EDTA
  • Certain cancers
  • Rhabdomolysis

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 –

  • Osteoporosis
  • Osteopenia
  • Depression
  • Chronic joint and muscle pain
  • Cataract
  • Fractures
  • Dental changes

Neonatal hypocalcemia can include –

  • Seizures
  • Apnoea or slowed breathing
  • Poor feeding
  • Jitteriness
  • 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
  • Lethargy
  • Fatigue
  • Palpitations

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

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