What is Vitamin D?
Vitamin D is prohormone that is important for bone health and muscle function. Furthermore, it plays an important role in immune function and protects us from cancer and cardiovascular disease. Our skin produces vitamin D after exposure to ultraviolet light from the sun. Once produced, vitamin D is activated by the liver and kidneys.
Vitamin D deficiency and its consequences for health
It is estimated that approximately 50% of elderly Australians (>65 years) have inadequate serum vitamin D levels, with figures varying between 40-100% in different groups of people. There is increasing evidence that all age groups, including children and pregnant women, are affected by vitamin D deficiency. Even among adolescents and preadolescents, the prevalence has been shown to be approximately 50%.
The following diseases and conditions are associated with low vitamin D levels:
• Soft bones and bone fractures without adequate trauma (osteoporosis, rickets)
• Falls and muscle weakness
• Bone, muscle, and joint pain
• Cancer (prostate, colon, breast, etc.)
• Heart attacks, occlusion of cardiac blood vessels
• Predisposition for infections (flu-like infections, urinary tract infections)
• Diabetes type 1
Should you be tested?
The most common cause of vitamin D deficiency is inadequate exposure to sunlight. Those who should be tested for a vitamin D deficiency include:
- Older Adults. Older adults are at increased risk of developing a deficiency in part because as they age, the skin cannot synthesize vitamin D as efficiently, they are likely to spend more time indoors, and they may have inadequate intakes of the vitamin.
- Individuals with limited sun exposure. Homebound individuals, women who wear long robes and head coverings for religious reasons, and people with occupations that limit sun exposure.
- Individuals with dark skin. Greater amounts of pigment melanin in the epidermal layer result in darker skin and reduce the skin’s ability to produce vitamin D from sunlight.
- Individuals with fat malabsorption. As a fat-soluble vitamin, vitamin D requires some dietary fat in the stomach for absorption.