Why do older people require more Calcium?

We all have heard once in our life time that older people need Calcium (Ca) supplements either through diet or through medicines. But why though? Why only older people and not young ones? What happens if we ignore this? And what are those supplements that provide the required Ca?

Hello Friends,

This time I will be taking us through this ‘old age’ question. (Pun intended)

In this article we will learn:

  • What roles do Ca play in our body?
    • It’s normal quantity and abnormalities.
  • Why its need increases with the age?
  • Complications of ignorance
  • How to avoid those complications?

What roles do Calcium play in our body?

  • Blood pressure: Ca causes vasoconstriction by working on smooth muscles cells of vessels. 
  • Blood clotting: Ca ions are required to activate many clotting factors such as IIa (active thrombin from inactive prothrombin i.e. factor II), IX (Christmas factor), X (Stuart factor) etc.
  • Heart contraction: I have already mentioned that Ca is required for contraction of smooth muscles i.e. involuntary muscle contraction. Similarly, our heart also requires Ca for its uniform functionality. (You know that cardiac muscle is involuntary and yet striated.)
  • Muscle contraction
  • Bone formation: Ca along with Phosphorus is needed to form bones and teeth.
    • Bones are constantly formed and deformed according to the homeostasis need.
    • There are cells like osteoblasts that form bones while osteoclasts dissolve bone.
  • Cancer prevention: Yes. You read it right. It has been found that dietary Ca (milk or other dairy products osteoblasts, salmon or sardines, leafy green vegetables like spinach) decreases risk of colorectal cancer. Though high intake can increase the risk of prostate cancer as well.
  • Renal stones: Here specifically, calcium-oxalate stones. One may think that ‘To prevent such stone formation, one must avoid Ca and oxalate intake’. Well, this is NOT TRUE.
    • Particularly, if the Ca is dietary and not supplementary.
    • Ca is actually needed to combine with oxalate salts in the gut so that it doesn’t move and accumulate in kidney.

Amount of Calcium

Normally, in serum – 8.4-10.2 mg/dL

Ionised (free calcium) – 4.4-5.2 mg/dL

What happens if the calcium is lower or higher?

Well, read below.

Low Ca

  • Tetany
  • Seizures
  • QT prolongation
  • Spasm
  • Twitching

High Ca

  • Renal stones
  • Thrones
  • Anxiety

Q1. What are the forms in which Ca exist in our blood?

A1. There are three main forms i.e. Free or active form(<50%), Albumin bounded (around 40%), Anions bounded (around 15%).

Q2. Can we predict which form of Ca will be more in blood?

A2. Actually, yes, we can. It happens as such:

  1. When pH is less, less albumin will bind to Ca i.e. more free Ca is present in blood.
  2. When pH is high, albumin binds more.
    • Happens in cramps or pain.
  3. When free Ca is more, it decreases PTH or parathyroid hormone secretion.

Why its need increases with age?

It takes about 10 years for all the bone in your body to be renewed. That is why paying attention to bone health is important in adults and not just in growing children.

Bone density is highest around the age of 30. It diminishes as you get older. This can lead to brittle, fragile bones that can break easily, even without a fall or other injury.

One of the main factors of decreased Ca in old people is the reduction in the Vitamin D.

Vitamin D in its active form i.e. 1,25(OH)2D or calcitriol, binds with Vitamin D receptor in guts and kidney (proximal and distal convoluted tubules, collecting ducts etc) and hence stimulates Ca absorption and reabsorption respectively.

It is more interesting to know that our intestine itself has very weak role in absorbing Ca as it absorbs only 15 to 20% Ca. Therefore, Vitamin D helps to supplement this absorption.

The remaining 85% of Vitamin D is synthesized in skin when it is exposed under sunlight.

Therefore, as in older age a person is less involved with outdoors and also as their skin thins, the synthesis of Vitamin D is reduced affecting the Ca content in the body.

Q3. Why the hypocalcemic effect is prominent in females after menopause?

A3. As menopause occurs, estrogen levels are reduced. Estrogen is significant for bone health as it’s an important regulator of bone metabolism. It works on osteoblast cells thereby reduction of estrogen weakens the bone density.

Therefor postmenopausal women are at risk of osteoporosis (A1).

A1. Osteoporosis: It is reduction in bone mass leading to porous bone which increases risk of fracture.

Signs: Pain in weight-bearing areas such as hip, lower part of radius, vertebrae.

Treatment: Doing workout, taking Vitamin D and Calcium supplements. Bisphosphonates such as Alendronate and Risedronate to suppress osteoclast activity.

Problems of hypocalcemia

  • Muscle pain, spasm, stiffness
  • Numbness and tingling of the extremities or lips
  • Depression or fatigue
  • Mood swings
  • Dementia
  • Inflamed or dry skin
  • Brittle nails
  • Weak and coarse hair
  • Kidney stones

Complications of hypocalcemia

  • Osteoporosis, as mentioned above
  • Osteopenia or bone loss
  • Papilledema (optic nerve swelling) leading to blindness
  • Life-threatening arrhythmia and seizures

Prevention or treatment

  • As mentioned, Ca rich diet such cheese, milk, yogurt
  • Vitamin D supplements
  • Treatment for acute Ca deficiency i.e. IV calcium gluconate that fulfils the amount of Ca in blood.

Published by signaturedoctor

I am a doctor-to-be pursuing my medical studies. I want to share my knowledge to fellow medical students and to other interested people.

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