Vitamin D is obtained from skin exposure to sunlight, or from food sources and supplements. Symptoms of vitamin D deficiency include rickets and osteomalacia. Let’s have a look at how to avoid vitamin D deficiency!
Why You Need Vitamin D?
Vitamin D is a fat soluble vitamin important for good health. It can be obtained from natural food sources, sunlight exposure, or as a supplement. Along with calcium, vitamin D helps to prevent osteoporosis in older adults.
Vitamin D is needed for:
- The absorption of calcium and phosphorous;
- Bone mineralisation, bone growth, and bone remodeling;
- Neuromuscular and immune function;
- And reducing inflammation.
Food Sources of Vitamin D
Vitamin D is found naturally in few foods. Good sources include cod liver oil and other fish liver oils, and fatty fish such as salmon, tuna, mackerel, and sardines. Vitamin D is also found in egg yolks, beef liver, cheese, and some mushrooms. Some foods are fortified with vitamin D, such as milk and milk products, margarine, bread, breakfast cereals, and orange juice.
Vitamin D is also available as a supplement or as an injection. Many health professionals suggest a daily intake of 5 mcg (600 IU) of vitamin D is adequate for adults aged 19 to 70 years, if there is no exposure to sunlight. This is increased to 15 mcg (800 IU) for adults aged 71 and over.
Sun Exposure and Vitamin D Synthesis
The most important source of vitamin D is sunlight exposure. Uncovered skin absorbs ultraviolet B (UVB) rays, which enable the body to synthesise vitamin D, but it is difficult to say exactly how much sun exposure is needed by each person. The intensity of UVB rays is affected by factors such as the time of year, time of day, latitude, cloud cover, smog, shade, and the amount of melanin in the skin.
Cancer Research UK advises only a short time in the sun is needed for the body to synthesise enough vitamin D. Continued sun exposure that allows for tanning or getting sunburned is unnecessary to meet vitamin D requirements, and increases the risk of skin cancer. People who live in countries of northern latitude can build up their vitamin D levels during the summer months in order to prevent vitamin D deficiency during the winter.
Risk Factors and Symptoms of Vitamin D Deficiency
Vitamin D deficiency can lead to bone softening due to poor bone mineralisation. This is known as osteomalacia (bone pains, weak muscles, and fractures) in adults, and rickets (deformity of the skeleton, bow legs, and aches and pains) in children. Long term, a vitamin D deficiency and poor calcium absorption may result in osteoporosis.
A vitamin D deficiency can be caused by not eating enough vitamin D-containing foods, getting too little sun exposure, or poor absorption of vitamin D.
The following groups of people are particularly vulnerable to vitamin D deficiency:
- People aged 50 and over. Older people cannot synthesise vitamin D as efficiently as they used to.
- People with limited exposure to sunlight. People who spend most of their time indoors, such as elderly people who are housebound or living in residential homes, are at risk as UVB rays cannot penetrate glass.
- If you cover your skin when outside. Fully covering skin with clothing when outside prevents UVB rays penetrating the skin.
- Darker skinned people. High levels of melanin filter out UVB rays, so more exposure to sunlight is needed to manufacture sufficient vitamin D.
- People who absorb vitamin D poorly. Liver disease, Crohn’s disease, cystic fibrosis, and gastric bypass surgery may result in poor absorption of vitamin D.
- People who are very overweight. Obesity increases the requirement for vitamin D.
If regular exposure to sunlight is not possible, more foods should be eaten that contain vitamin D. Supplementation may also be necessary to avoid symptoms of vitamin D deficiency.