What is Vitamin D Requirement?

Vitamin D is the sunshine vitamin. The human body can synthesise sufficient vitamin D when the skin is exposed to adequate amounts of sunlight. The dietary sources of vitamin D include food and dietary supplements. Vitamin D plays an essential role in the regulation of metabolism, calcium, and phosphorus absorption of bone health. Vitamin D adequacy is best determined by measurement of the 25-hydroxyvitamin D concentration (25(OH)D levels) in the blood.

How It Affects Your Body

Vitamin D aids in increasing calcium absorption in the intestines and maintaining bone growth and remodeling. Low vitamin D levels can cause soft bones (osteomalacia), deformed bones (rickets), and fragile, weak bones (osteoporosis). Low vitamin D levels can also affect the immune system and neurotransmitter productions, causing weakness, tiredness, nausea, and depression.

Symptoms

Old Age

Older individuals tend to have reduced sunlight exposure, dietary vitamin D intake, and produce less vitamin D under UV exposure.

Limited Sun Exposure

Limited UV is available to convert 7-dehydrocholesterol to pre-vitamin D3 in the skin.

Dark Skin

High melanin content in the skin reduces UV pnetration into the epidermis. Thus, less 7-dehydrocholesterol is converted to pre-vitamin D3.

Digestive Disorders

Vitamin D is fat-soluble and is absorbed in fat molecules in the intestines. Thus, reduced fat absorption reduces vitamin D absorption.

Obesity

Obese individuals have more subcutaneou fats that accumulate more vitamin D. This reduces the amount of available plasma vitamin D levels as well as increases dietary intake requirements.

Gastric bypass surgery

Individuals who have undergone gastric bypass surgery have less of the upper small intestines which absorb fats and vitamin D.