Vitamin D is necessary for strong bones, muscle function and general health. That is why it is important to ensure you are getting enough. Vitamin D is produced naturally in the body when the skin is exposed to ultraviolet (UV) radiation from the sun. For people who are not able to access the amount of sunlight exposure required to maintain their vitamin D levels, it is vital that they receive it from other sources. Listed below are ways to maintain healthy vitamin D levels.

Sensible sun exposure

It is well established that the sun contributes significantly to the production of vitamin D but too much sunlight exposure can have detrimental effects on our health. This is why it is important to take a balanced approach. During summer, most people can achieve enough vitamin D from just a few minutes of sunlight when going about their regular daily activities. In winter, in southern areas of Australia, people may need two or three hours of sunlight per week to their face, arms and hands, or equivalent area of skin, to maintain adequate levels.¹

Vitamin D rich foods

There are small amounts of vitamin D in some foods, which can contribute to your overall vitamin D levels. This includes fatty fish such as mackerel, salmon and sardines, fish liver oils, eggs from hens that have been fed vitamin D and products that are fortified with vitamin.² It is very difficult to obtain enough vitamin D from diet alone with most people only acquiring 5-10% of their daily intake of vitamin D from food.³ It is therefore important to include other vitamin D sources such as sensible sun exposure or a vitamin D supplement, to ensure adequate vitamin D levels are maintained.

Vitamin D supplements

Vitamin D supplements may be necessary to maintain adequate levels in some people. This includes those who:

• Don’t spend enough time in the sun
• For health or cosmetic reasons
• Due to having an occupation with little sun exposure such as office workers, night- shift workers and taxi drivers³
• Hospitalised or institutionalised individuals³
• Have naturally dark skin – People with dark skin synthesise less vitamin D when exposed to sunlight compared to those with fairer skin²
• Wear concealing clothing for cultural or religious reasons
• Are older – The elderly have a reduced capacity to produce vitamin D in their skin when exposed to sunlight and are also more likely to stay indoors²
• Are overweight – When vitamin D is produced in the skin it is deposited in the body’s fat stores for later use. This makes it less available to people with large stores of body fat.²

Daily exercise

Regular exercise can assist with the body’s production of vitamin D,³ and may therefore be a useful adjunct to maintaining healthy vitamin D levels.

Calcium is an essential building block of bones and teeth and is vital during childhood when the skeleton is actively growing. It also plays a key role in many functions of the body including muscle contraction, blood vessel constriction and relaxation, the secretion of hormones and enzymes, and the nervous system. Our bones hold onto most of the body’s calcium, which must be ‘topped up’ regularly from the diet.

During childhood, the body needs high amounts of calcium to support the development of the skeleton and to achieve maximum bone growth. If a child doesn’t consume enough calcium in their early years it may affect their skeletal health in later life. Unfortunately, it’s estimated that 70% of Australian children are not meeting their recommended dietary intake of this important bone building mineral.¹ This may be due to dietary limitations such as allergies or intolerance to calcium-rich foods, or because many kids go through periods of fussy eating making it difficult to get the calcium their growing bones need.

How much calcium is enough?

The recommendations for calcium intake throughout childhood are as follows:²

Good sources of calcium

Good sources of calcium for kids include:

• Milk and milk products – One cup of milk or 200g of yoghurt provide around 300mg of calcium.¹
• Green leafy vegetables – One cup of broccoli contains about 45mg of calcium.¹
• Tofu and soy milk – Calcium-fortified soy milk contains around 300mg of calcium per serve¹ and half a cup of tofu, depending on the brand, provides just over 250mg.³
• Sardines and salmon (with soft edible bones) – Half a cup of canned salmon contains around 400mg of calcium.¹
• Nuts and seeds – Brazil nuts, almonds and unhulled tahini are all good calcium sources. A small handful of almonds provides around 40mg of calcium.¹
• Calcium supplements – A specialised kids calcium supplement may be beneficial to support bone growth in childhood, especially in times of dietary limitations or during periods of fussy eating.

For calcium to be effective in bone growth and development, it’s also important that your child obtains adequate amounts of vitamin D. This can be achieved through sensible sun exposure or by taking a kid’s vitamin D supplement.

Vitamin D is a unique vitamin, since adequate levels are usually maintained through exposure to sunlight. If exposure to sunlight is sufficient, dietary vitamin D can be considered unnecessary.

Current food supplies and patterns of eating also make it virtually impossible to obtain enough vitamin D from dietary sources alone. ¹

Most people can produce enough vitamin D for their body’s needs through regular daily activity with incidental exposure to the sun. In summer, this equates to a few minutes of sunlight on the face, arms and hands or equivalent area of skin, on either side of peak UV periods (midday), on most days of the week.

In winter in areas such as the southern parts of Australia, UV radiation levels are less intense. This means that people may need as much as two to three hours of sunlight exposure to the face, arms and hands, or equivalent area of skin, spread over the course of the week. ² In the winter months, people also spend more time indoors and wear more clothing due to colder temperatures. For this reason, vitamin D deficiency is usually more common in winter.¹

If the level of sun exposure required to maintain vitamin D levels is not possible, oral supplementation may be necessary. In summer, sun protection measures, such as limiting sun exposure, wearing protective clothing and hats, and the use of sunscreen means that vitamin D production is reduced even in Australia’s warm climate. The application of sunscreen with a sun protection factor as low as ten reduces UVB radiation necessary for vitamin D synthesis by 90%. ³

The current Nutrient Reference Values for Australia and New Zealand for vitamin D are as follows: ¹

• Children (boys and girls 1-18 years old): 5.0 mcg/day
• Adults (men and women 19- 50 years old): 5.0 mcg/day
• Elderly adults (men and women 51- 70 yrs): 10.0 mcg/day
• Elderly adults (men and women > 70 yrs): 15 mcg/day

Sunlight exposure and environmental factors vary widely between individuals, which makes vitamin D requirements difficult to assess. If you are concerned about your vitamin D status and whether you may need a supplement, speak to your doctor. They will be able to conduct a simple blood test and recommend the level of oral supplementation that is required.

Long work hours with mounting work expectations and pressure may mean that those who work in an office have little sun exposure, putting them at risk of vitamin D deficiency. Research shows that one in five Australian workers are too busy during the day to go outside and get some sunshine, and around one in three eat lunch at their desk.¹ Unfortunately, this may be compromising their bone, muscle and general health. Office and other indoor workers should be encouraged to take a ‘Dbreak’ (vitamin D‐break) and step outside for a daily dose of sunlight by:

1. Eating alfresco – Rather than eating your lunch at your desk, take a break and eat outdoors. In addition to obtaining greater sun exposure, it gives you a chance to de‐stress and maximize your productivity in the afternoon.
2. Going for a lunch time walk ‐ Organize regular lunchtime or afternoon walks with colleagues. It’ll help you to clear your head, regain focus and at the same time, gain a healthy dose of sunshine. Roll up your sleeves to expose your skin, for greater benefits.
3. Having outdoor meetings – Rather than always having indoor meetings, host one outdoors. A change of scenery may also help boost productivity and creative thinking.
4. Organizing a staff BBQ – A regular lunch time BBQ or sausage sizzle can encourage everyone to step outside and away from their computer screens.
5. Hosting a sports/team building session – Organize a cricket, bowls or tennis match with coworkers to promote team building and to get a boost of sunshine and vitamin D.
6. Setting up a work station in the sun – Ask your manager if you can take your laptop to an outdoor table and work outside every once in a while.
7. Taking long work calls outdoors – If you have a long work call, consider taking it on a bench in the sun.
8. Parking further away or walking to and from the station– If you park your car further away from the office, or walk to and from the train or bus station, you may get some incidental sun exposure and extra exercise. Or if you’re able, try cycling to work.
9. Participating in charity runs or challenges – If your commitments at work mean that you’re not able to free up time for an outside break through the week, consider participating in company‐led charity runs or other challenges on the weekend. It will help you to get to know your colleagues and importantly, obtain some weekend sunshine.
10. Exercising outdoors before work – Wake up earlier and go for a brisk morning walk, jog or cycle before work. You’ll be increasing your vitamin D levels whilst starting the day in a healthy and positive way.