Vitamin D- often low, but how do you know?

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What is Vitamin D and how much should I be getting?

Vitamin D is important for strong bones and muscles, as well as general health. It also helps to regulate the body’s calcium levels. However, there is little Vitamin D in the average diet- and whilst it’s present in eggs, oily fish, baby formula and certain brands of milk, we get less than a quarter of our Vitamin D from food. Most of our Vitamin D comes from exposure to sunlight- it is formed when ultraviolet B (UVB) rays hit our skin. People generally need 400-600 iu of Vitamin D per day (the elderly need a bit more, and infants under the age of 1 year need 400iu).

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How do I know my Vitamin D is low- and what level is normal?

Many people have low levels of Vitamin D, especially in winter, but will still feel entirely well. Sometimes it might be picked up on a routine blood test. It’s recommended that the levels of Vitamin D in our blood should be at least 50nmol/L at the end of winter, and a little higher during summer, at 60-70nmol/L or more.

How can low Vitamin D damage my health over time?

If your Vitamin D is low over a long period of time, you can develop a variety of health problems, including bone and muscle aches, osteopenia or osteoporosis (thinning of the bones which causes a higher risk of fractures). In children “rickets” can develop- this is weakening of the bones and a bow-legged or knock-kneed appearance. Some experts believe that low levels of Vitamin D may be linked with higher risk of Diabetes, Multiple Sclerosis, Heart Disease, certain forms of cancer, immune system disorders and mental health problems. However, it’s not certain if taking extra Vitamin D can protect against any of these conditions- more research is needed.

Who is most at risk?

Low Vitamin D is seen more often in people who have little natural sun exposure- due to indoor work, or wearing clothes that cover a lot of skin. It’s also more common in the elderly, people with darker skin tones, and anyone with disability, long term illness, obesity, bowel disease, kidney disease, or long hospital admissions. Certain drugs can reduce levels, such as epilepsy medications. Breastfed babies are also at risk – particularly those whose mothers have had low Vitamin D levels. Babies who are fully breastfed and have another risk factor (e.g dark skin, or a mum with low levels) can start Vitamin D supplement drops at birth without any need for a blood test. 400iu is the usual dose, and treatment should continue till 1 year of age.

How can I get enough Vitamin D?

It’s important to strike a balance between getting enough sun exposure while not increasing your risk of skin cancer. Exposure to the face and arms is usually enough. In summer, it’s OK to allow some sun exposure outside peak UV times- mid-morning or mid-afternoon are best. If the UV index is above 3 (that’s all states during summer, and some states during winter), sun protection is still needed. In winter, you’ll need longer periods of sun exposure to meet your Vitamin D needs- around midday is best. When the UV index is less than 3, sun protection is not needed. 6-7 minutes of exposure is enough for people with light skin, but those with darker skin may require 18-40 minutes, because the pigment in their skin acts as a natural sunscreen. You can check the current UV index at www.myuv.com.au

If low levels are found on a blood test, oral Vitamin D supplements may be recommended- the dose will depend on your age, your Vitamin D blood test results, and amount of sun exposure you get. Several months of treatment are often needed. Your doctor or chemist will advise you. You may need to have levels rechecked. It’s also recommended to have 3 serves of calcium-rich food per day, such as dairy.

If you have further concerns about low Vitamin D, speak to your doctor or maternal & child health nurse.

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