Vitamin D: How do you know if you are Getting Enough?

Vitamin D, the sunshine vitamin, is famous for its role in helping our bodies absorb calcium to keep our bones strong.

Despite the abundance of sun in Australia, more than 20% of Australian adults are deficient in vitamin D.  

To keep our bones healthy and strong adults need 5 - 15 µg of vitamin D a day, increasing as we get older. Australians get about 90% of their vitamin D requirements from the sunlight on their skin, and 10% from the food they eat. So, what happens when we spend so much time indoors?

Can we get enough vitamin D in winter?

Spending a lot of time indoors or being housebound is a risk factor for low vitamin D.

We see this happen naturally with changes of seasons. The Australian data on vitamin D levels shows that in summer 16% of us are low in vitamin D, while in winter this increases to 26%, and even higher among those living in Tasmania (46%) and the Australian Capital Territory (43%) during the colder months.

Spending time outside is important. As well as being good for our mental wellbeing, it helps restore levels of vitamin D and whether it’s a cuppa on the balcony, some gardening in the backyard, chatting to a neighbour, walking to the shops or exercising outside. 

How much time in the sun do we need to get enough vitamin D?

It’s tough to give an exact amount of time as this will depend on a range of factors, including where you live, what time of day it is, the colour of your skin and how much skin is exposed.

Generally, adequate vitamin D levels can be reached through regular incidental exposure to the sun. When the UV index is 3 or above, such as during summer, just a few minutes outdoors on most days of the week can help with vitamin D levels. When the UV index falls below 3 (e.g. in winter), spending time outdoors in the middle of the day with some skin uncovered can be effective. 

  If the UV index is 3 or above, sun protection is recommended on these days. 

Can I get Vitamin D from food?

You can get vitamin D in small amounts from foods including eggs, oily fish, UV-irradiated mushrooms. What’s that you ask? Like our skin, mushrooms convert the sunlight they absorb into vitamin D, so placing mushrooms in the sun can increase the amount of vitamin D they contain. Eating a 100g serve of mushrooms that has been left in the sun for an hour, will provide your daily dietary vitamin D needs.

There are also several foods that have been fortified with vitamin D including soy milks, almond milks and some margarines and milk.

In cases of vitamin D deficiency, health professionals may also prescribe vitamin D supplements.

What happens if I don’t get enough vitamin D?

You may not notice low vitamin D levels at first, however if it’s severe you might experience aches, cramps and pain in your muscles. Low levels of vitamin D can also increase your risk of bone and joint pain and the chance of fractures and broken bones, especially if you are over 50. It’s also a risk factor for osteoporosis. 

Osteoporosis makes bones brittle and occurs when your bones lose minerals, like calcium, quicker than our body can replace them. Vitamin D plays an important role in helping our body absorb calcium. 

In infants and children, moderate or severe vitamin D deficiencies can lead to soft bones or rickets as well as dental issues like cavities.   

Low vitamin D levels have also been linked to other health conditions like colorectal cancer, cardiovascular disease, polyendocrine metabolic ovarian syndrome or PMOS (previously called polycystic ovarian syndrome or PCOS) and immune system problems. If you have any questions or concerns about your vitamin D levels please speak to your GP or a dietitian.