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Could you be at risk of low vitamin D?

Vitamin D deficiency is more common than many people may realise. Even in our sun drenched country, it is estimated that one in three Australians may have less than adequate vitamin D levels. Low Vitamin D levels may not result in any obvious symptoms but it can have significant health effects. The following groups of people have an increased risk of being deficient in this important nutrients:

People with little or no sun exposure

The main source of vitamin D is from sensible exposure of the skin to UVB (ultraviolet B) radiation from the sun. Some groups at risk of receiving little or no sun exposure include:

  • Those who wear concealing clothing for cultural or religious purposes, which may not allow adequate skin exposure. To obtain enough vitamin D, a person’s face, arms and hands, or equivalent skin area, need to be exposed for a period of time on most days of the week.
  • Individuals who avoid the sun for health or cosmetic reasons.
  • Those who are house-bound, hospitalized or institutionalized.
  • People in occupations where they have limited sun exposure throughout the day including factory workers, taxi drivers, office workers and night-shift personnel.

Individuals with naturally dark skin

Melanin, the pigment in skin, acts as a UVB radiation filter and reduces the amount of vitamin D produced. People with darker skin therefore require much longer sun exposure times than those with fairer skin to produce adequate vitamin D, which may not be possible to achieve.

Older people

The elderly have a reduced capacity to produce vitamin D when exposed to the sun. A person 70 years of age exposed to the same amount of sunlight as a 20-year-old person makes approximately 25% of the vitamin D3 that the 20-year-old person can make.

People with medical conditions that affect how the body metabolises vitamin D

Vitamin D status can be affected by certain health conditions including problems that cause malabsorption such as coeliac disease and inflammatory bowel disease, as well as conditions affecting the liver or kidney, which are involved in vitamin D metabolism.

  • People taking certain medicines – some medicines can increase the breakdown of vitamin D in the body.

Very overweight individuals

Being very overweight predisposes a person to being low in vitamin D. When vitamin D is produced in the skin or ingested it is deposited into body fat. This makes it less available to those with large body fat stores.

Breastfed babies with other risk factors of low vitamin D

Exclusively breast-fed infants are at a greater risk of being low in vitamin D, especially if they have dark skin or little sun exposure, as breast milk is not a good sole source of vitamin D. Infants of mothers with low vitamin D, or who had low vitamin D in pregnancy, are also at risk, as babies obtain their initial vitamin D stores from their mothers. If you think you fall into one of these categories and may be at risk of low vitamin D levels, consult your GP who may recommend a suitable vitamin D supplement for your needs.