Vitamin D – Benefits, Sources & Dosage

Vitamin D refers to a group of fat-soluble compounds essential for various bodily functions. The three main forms are:

These are converted in the liver and kidneys into the active hormone form known as calcitriol.

Regulates blood calcium levels (enhances absorption in the intestines and calcium release from bones).
Supports cell division and has anti-cancer properties.
Contributes to the immune and nervous system function.

Vitamin D can be measured in International Units (IU) or micrograms (mcg).

5 mcg = 200 IU
Optimal blood levels: At least 30 mg/L (or 75 nmol/L for 25-hydroxy cholecalciferol).

Sun exposure: Moderate sunlight exposure is crucial for natural Vitamin D synthesis.
For fair-skinned individuals, 20-30 minutes of daily sun exposure is enough.
Darker skin tones may require up to 3 hours for the same effect.
Factors such as clothing, glass, clouds, and sunscreen reduce Vitamin D production.

Prevention of heart attacks and strokes
Prevention & treatment of osteoporosis
Improving balance and fall prevention in elderly individuals
Supporting immune function
Reducing the risk of cancers (skin, lung, breast, colorectal, prostate, leukemia)
Supporting treatment of multiple sclerosis

Excessive intake of Vitamin D supplements may be toxic. Avoid combining multiple Vitamin D supplements.

Excessive doses (over 25 mcg/day for children and 50 mcg/day for adults) may cause toxicity.
Symptoms of hypervitaminosis D include:

Note: Excess sun exposure does not lead to toxic Vitamin D levels but may accelerate skin aging.

Vitamin B5 (pantothenic acid) is necessary for Vitamin D synthesis.
Medications that reduce fat or cholesterol absorption (e.g., cholestyramine) may reduce Vitamin D absorption.
Alcohol consumption slows Vitamin D conversion in the bloodstream.
Some medications (e.g., antacids, thiazide diuretics) may cause mineral imbalances when taken with Vitamin D. Consult your doctor.