Vitamin D, or the sunshine Vitamin is often one of the most overlooked nutrients human beings require for optimum function. Vitamin D is required for bone growth and remodelling, cell growth and neuromuscular and immune function. It is also required for its anti-inflammatory effects. Our most abundant source of vitamin D is sunlight, though it can also be acquired through food as well as supplementation.
There are however key demographics and groups of individuals who are more likely to be deficient in Vitamin D. Other factors that come into play are seasonal changes, latitude, time of day, cloud cover and skin melanin levels.
People who are most likely to suffer from Vitamin D deficiency are:
- Individuals with naturally brown or dark skin
- The elderly population who are less likely to go outside into the sunlight
- Individuals who wear clothing that fully conceals them whether for religious or personal reasons.
- Pregnant women and babies who are breast-fed by Vitamin D deficient women
- Individuals who choose to purposefully avoid the sun
If you fall under one or more of these categories, it is very likely that you are vitamin D deficient, putting you at greater risk from a variety of conditions including osteoporosis.
Vitamin D Requirements
Vitamin D is needed for a variety of reasons with one of the most important being the promotion of calcium absorption in the gut and intestines. In this way the serum calcium and phosphate concentrations allow for the normal mineralisation of bone. It is also understood that good levels of Vitamin D and calcium help to prevent osteoporosis and other similar conditions in the elderly populace.
If you have less than 25nmol/L of 25-hydroxyvitamin D in your bloodstream than you are vitamin D deficient. Such low levels can result in brittle or malformed bones and can even cause rickets in children. Low levels of Vitamin D has on numerous occasions also been connected to conditions such as cardiovascular disease, diabetes mellitus, improper immune function, and even multiple sclerosis.
Recommended intakes for Vitamin D are as follows:
- For postmenopausal women and those aged over 50: 400-800 i.u. per day.
- For people aged over 65 a minimum of 600 i.u. is necessary.
- Individuals aged 25-50 years should acquire 400 i.u. of Vitamin D daily.
Fixing Your Vitamin D Deficiency
Eating a diet rich in Vitamin D is one easy way to modify your deficiency; however Vitamin D is only available plentifully in a few food sources. The main sources re oily fish, fish oils, liver, meat, eggs and foods which have been fortified with Vitamin D like cereals, eggs, orange juice, bread, milk and margarine.
Exposing the body, especially the face, arms and hands to sunlight is also another way of raising vitamin D levels. Roughly ten to fifteen minutes of sunlight three or four times a week should be enough to keep vitamin D levels raised. The amount of sunlight required increases with age as the body becomes less able to manufacture Vitamin D through sun exposure. Additionally sunscreen is known to hinder the body’s ability to manufacture Vitamin D.
Vitamin D and calcium supplements are also available and would prove quite beneficial if you are deficient in these nutrients. The Institute of Medicine reccomends no more than 2000 i.u. of Vitamin D per day as excess levels of it or calcium are known to be toxic. Symptoms of excess vitamin D consumption are decreased appetite, dehydration, fatigue, irritability, muscle weakness and vomiting. Supplements that provide Vitamin D only are preferable to multivitamins as Vitamin A (which will often be found in multivitamins) is often contraindicated for pregnant women and elderly individuals.