The information provided on this website is intended for general informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It does not take into account a person’s individual or specific health needs, including but not limited to, health status, allergies, medical conditions, prescribed medications and/or health supplements. You should always consult with your medical doctor or other qualified health provider to discuss your individual health needs.
A Guide to Safe Sun Exposure to Increase or Maintain Vitamin D Levels
Vitamin D is essential for optimal health and vitality, including but not limited to, maintaining healthy bones, supporting the immune system and reducing the risk of chronic diseases and mental health disorders. One of the most effective ways to obtain vitamin D is through safe sun exposure or more specifically skin exposure to UVB radiation produced by the sun. However, UV radiation levels vary depending on location, time of year, time of day, cloud coverage and the environment.
The recommended daily intake (RDI), of vitamins such as vitamin A, B group vitamins, plus C, E and K is usually met or exceeded through diet. However, unlike its vitamin cousins, vitamin D levels obtained from food sources are often inadequate. Because diet alone is usually insufficient in providing nutritional vitamin D to meet the needs of the body, safe sun exposure and/or vitamin D supplements is often recommended.
However, sun exposure is not without risks and it is a delicate balance between exposing the skin to sunlight (to synthesise vitamin D), while minimising the risk of skin damage, which can lead to skin cancer.
In this health insight, we provide a guide to safe sun exposure to increase or maintain vitamin D levels. In this guide, safety and minimising health risks associated with sun exposure are thoroughly considered.
Understanding Vitamin D Production and Storage
When skin is exposed to sunlight, specifically ultraviolet B (UVB) rays, it synthesises vitamin D. Factors such as skin type, geographic location, season, time of day, exposure time, cloud coverage and the environment all influence the amount of vitamin D produced.
Vitamin D is fat soluble vitamin, which means the body can store vitamin D in adipose cells (fat tissue). During summer when days are longer and there is more sunlight, our bodies store excess vitamin D. Vitamin D synthesis during winter is significantly reduced because our our skin is less exposed to sunlight. To meet the body’s daily requirement of Vitamin D, it breaks down adipose cells in fat tissue, so that vitamin D can be released into the bloodstream. Therefore, it is important to synthesise and store adequate vitamin D during the warmer months to last over winter. This is why Vitamin D levels in the serum (shown in blood pathology tests) should be highest at the end of summer and lowest at the end of winter.
This health insight primarily focuses on safe sun exposure as a process to synthesise vitamin D. It touches on vitamin D deficiency, as well as, the health benefits associated with adequate vitamin D levels. However, to learn more about vitamin D and its role in supporting overall optimal health and vitality, we encourage you to view an earlier insight discussing vitamin D.
Recommended Daily Requirements of Vitamin D
Recommended daily requirements of vitamin D, set by the National Health and Medical Research Council (NHMRC) of Australia, are the same for all genders but vary depending on age group. Generally, people aged between 1 and 49 require 5 micrograms of vitamin D each day. For people aged 50 and above the recommended requirement is increased. The rationale for increased vitamin D later in life primarily due to the vitamins beneficial effects on balancing calcium levels in circulating blood to promote bone health. Reduced skeletal bone density, including osteoporosis is more common in older people and vitamin D assists to reduce this process. A decline in the functioning of the immune, neurological and cardiovascular systems is often associated with older people and higher doses of vitamin D are recommended to support optimal health and vitality due to its affinity with these systems.
The below table below provides the daily requirements of vitamin D, recommended by the Australian government for each age group. Vitamin D is measured in micrograms (mcg) and abbreviated either as μg or mcg. Although some countries and/or products use international units (IU) to measure vitamin D.
Conversely, pathology tests quantify vitamin D levels in blood-serum using nanomoles (nmol). For example, pathology labs calculate levels of circulating vitamin D (25-hydroxy-vitamin D) in blood as nanomoles per Litre of blood-serum. Pathology results commonly report this measurement as [X number] 25-hydroxy-vitamin D nmol/L.
The safe and tested upper limit (UL) is the maximum requirement of vitamin D each day. Vitamin D is considered toxic in high doses, therefore the upper limit should not be exceeded. Overdose, toxicity and unwanted side effects can be avoided by ensuring the recommended dose of vitamin D is followed, which should be well below the upper limit.
| Age Group | Mcg / IU | Upper Limit | |
|---|---|---|---|
| Babies & Infants | 0 - 12 Months | 5 mcg / 200 IU | 25 mcg / 1,000 IU |
| Children & Adolescents | 1 - 18 Years | 5 mcg / 200 IU | 80 mcg / 3,200 IU |
| Adults | 19 - 49 Years | 5 mcg / 200 IU | 80 mcg / 3,200 IU |
| 50 - 69 Years | 10 mcg / 400 IU | ||
| 70+ Years | 15 mcg / 600 IU | ||
| Pregnancy & Lactating | N/A | 5 mcg / 200 IU | 80 mcg / 3,200 IU |
Vitamin D and its Role in Optimal Health and Vitality
This health insight primarily focuses on safe sun exposure as a process to synthesise vitamin D. It touches on vitamin D deficiency, as well as, the health benefits associated with adequate vitamin D levels. However, to learn more about vitamin D and its role in supporting overall optimal health and vitality, we encourage you to view an earlier insight discussing vitamin D.
Health Benefits of Vitamin D
Vitamin D is essential for various bodily functions including the immune, neurological, cardiovascular and respiratory systems. It also has an affinity to the musculoskeletal system by reducing muscular pain and muscle weakness. The integrity of the skeletal system, including bone health is also maintained by adequate vitamin D levels in the body. Adequate levels of vitamin D also supports the health of the mother and developing baby during pregnancy.
Vitamin D Deficiency
Vitamin D deficiency can lead to health conditions such as frequent colds and flus, mood disorders, cognitive decline, osteoporosis, muscle weakness and pain, asthma, and psoriasis. Vitamin D also has a role in reducing the risk of cardiovascular disease, diabetes, autoimmune diseases and other chronic diseases. Pregnant women with low vitamin D levels may have a higher risk of developing pre-eclampsia and/or gestational diabetes.
People at Most Risk of Vitamin D Deficiency
Some people may not be able to access the sun exposure required to help them maintain sufficient vitamin D levels. People at most risk of vitamin D deficiency include:
Naturally dark-skinned people who need more UV exposure to produce adequate levels of vitamin D as the pigment in their skin reduces UV penetration
People who cover their skin for religious or cultural reasons
People who avoid sun exposure because they have previously had skin cancer or are at high risk of skin cancer.
Elderly/frail, chronically ill or institutionalised people who live mostly indoors
Drug-induced deficiency due to people taking particular medications, or those who have conditions causing poor absorption of calcium and vitamin D.
Over-exposure to UV is never recommended, even in cases where vitamin D deficiency is indicated. People in these groups should consult a qualified health professional to determine if vitamin D deficiency exists and for advice on increasing vitamin D levels, including vitamin D supplementation.
Prevalence of Vitamin D Deficiency in the Australian Population
On average, across Australia, more than one in three people experience vitamin D deficiency at any given time (ranging from mild to moderate to severe deficiency). Vitamin D deficiency has a direct correlation with the seasons, which is supported by a significant increase in the number of people experiencing and reporting vitamin D deficiency during the winter months. During the summer months, vitamin D deficiency remains widespread, although the severity of deficiency is less significant and easier to manage. The role of seasonal changes and its direct effect on fluctuating levels of vitamin D should not be underestimated. Although, several other factors effect the rates of vitamin D deficiency, including but not limited to, geographical location and latitude, occupation, skin type and health considerations. Vitamin D deficiency is also influenced by social and cultural determinants, including religious observance (restricting or reducing sun exposure due to covering the skin).
The below table shows the percentage of the Australian population clinically diagnosed with vitamin D deficiency at the end of summer and winter (broken down by region).
Determining if a Vitamin D Deficiency Exists
A significant number of Australians are clinically deficient in vitamin D and a high proportion of this population will be unaware. It’s perhaps fair to say that most Australians do not know their vitamin D status, which involves periodically reviewing vitamin D levels in the body and correcting changes when necessary.
The most common diagnostic tool used in Australia to determine vitamin D status and therefore identify if a deficiency exists is a blood pathology test. You can request a routine blood test (usually annually) via your GP / Doctor, although vitamin D is usually an additional test that needs to be added to the pathology request documentation, as it does not form part of the standard tests captured in a routine blood pathology request. Testing is limited to people at increased risk of Vitamin D deficiency with 11 groups described in the MBS (Medicare Benefits Schedule). Your Doctor / GP may ask you a few questions and check for possible signs and symptoms to determine if a vitamin D deficiency is likely before adding the vitamin D test to your pathology request documentation.
Your Doctor / GP may respectfully decline your request to test for vitamin D if their professional medical opinion has ruled out the likelihood of vitamin D deficiency, following a health assessment during the consult. Over recent years, Doctors / GPs are less inclined to test for vitamin D unless they are satisfied that you fall into one of the 11 groups defined by the MBS. It is also highly likely that Doctors / GPs are be experiencing some pressure from Medicare and/or the RACGP, which is a governing body that represents GPs and their profession. This is due to an influx of people requesting vitamin D tests over the past 10 years or so and the additional financial burden this places on Medicare.
If your Doctor / GP respectfully declines your request to add the vitamin D test to the pathology request form and you do find yourself in a definite need to determine your vitamin D status, there are a couple of options available to you:
Review the primary signs and symptoms of vitamin D deficiency (mentioned earlier), identify the signs and symptoms you are experiencing to see if there is a pattern. Also consider the 11 groups defined by the MBS. Be persistent with your Doctor / GP and succinctly explain to them the reasons why you believe a vitamin D deficiency exists and/or fall into one of the 11 groups defined by the MBS as people at a higher risk of vitamin D deficiency.
Ask your Doctor / GP to provide you with information specifically relating to the vitamin D test, including the out-of-pocket costs involved if you were to independently and privately pay for the test (essentially, you pay for the cost of the vitamin D test, instead of it being a bulk-billed cost to Medicare). This test is fairly reasonable. At the time of writing this health insight, the cost of a vitamin D test is around $30.00.
Alternatively, a Naturopathic Practitioner at Optimal Vitality is qualified to complete pathology request forms and you can arrange to have the results of your vitamin D test (or any blood pathology results) sent to us. Naturopathic Practitioners at Optimal Vitality regularly request pathology, functional and other diagnostic tests for their clients and are well-versed in interpreting and understanding diagnostic reports and results to inform their clients and recommend treatment strategies. However, all tests are billed privately to the client. Unfortunately, the Medicare bulk-billed structure is unavailable to Naturopaths. Medicare is a structure afforded to Doctors / GPs and other professionals practising conventional medicine only.
Remember to check-in regularly with yourself during the year but especially during winter. You don’t always need a blood test to recognise a possible deficiency. Review the signs and symptoms of vitamin D deficiency. but avoid self-diagnosing and jumping to conclusions An example may be that you are experiencing frequent cold and flus during winter, which may be unusual for you in comparison to previous years. Although, while frequent cold and flus may be an indication of vitamin D deficiency, it is also important to consider and rule out other reasons too.
The below table shows optimum levels of 25-hydroxyvitamin D in serum (vitamin D levels in the blood) at the end of summer when vitamin D levels should be at its highest and vitamin D levels by the end of winter when they are usually at there lowest. This table also demonstrates vitamin D levels correlating to deficiency, as well as, naturopathic vitamin D goals and possible toxicity if vitamin D levels exceed safe upper limits.
Vitamin D is measured as nanomoles of 25-hydroxyvitamin D per litre of blood / serum.
| Vitamin D Levels | End of Summer | End of Winter | Naturopathic |
|---|---|---|---|
| Optimum Levels | >70 nmol/L | >50 nmol/L | 100 - 200 nmol/L |
| Deficiency | <70 nmol/L | <50 nmol/L | <100 nmol/L |
| (Mild Deficiency) | 50 - 70 nmol/L | 30 - 50 nmol/L | - |
| (Moderate Deficiency) | 33 - 49 nmol/L | 13 - 29 nmol/L | - |
| (Severe Deficiency) | <33 nmol/L | <13 nmol/L | - |
| Toxicity (possible) | - | - | >250 nmol/L |
Factors to Consider Before Sun Exposure
Discussed earlier is the delicate balance between the health risks associated with vitamin D deficiency, health benefits of synthesised vitamin D by exposure to the sun, and health risks associated with sun exposure. Provided below are several factors to consider before initiating skin exposure to the sun.
Determine Skin Type
Fair skin: Fair-skinned individuals produce vitamin D more quickly but are also more susceptible to sunburn and skin damage.
Darker skin: Individuals with darker skin require more sun exposure to produce the same amount of vitamin D due to higher levels of melanin, which provides some natural protection against UV rays. Health experts widely report that people with darker skin need between 3-6 times longer exposure times in the sun compared to people with fair skin. So for example, during the summer months in Victoria, the recommended daily sun exposure time to produce adequate vitamin D for a person with fair skin is around 8 minutes and therefore the recommended daily exposure time for a darker skinned person is between 24 to 48 minutes. Skin type, season and latitude are variables that are considered by health experts in determining daily sun exposure recommendations.
The Fitzpatrick Skin Phototype is a commonly used tool to describe a person’s skin type in terms of response to ultraviolet radiation (UVR) exposure. Visit this resource to learn more about skin phototypes and complete the short quiz to determine your skin type.
Optimal Time for Sun Exposure
Sun exposure during midday is most effective for vitamin D synthesis but this time period also poses the highest risk for skin damage. As a general rule, the Cancer Council of Australia recommends sun exposure when the UV Index is below 3.
Summer months: Either slightly before 10:00 am or just after 2:00 pm
Winter months: Between 10:00 am to 2:00 pm (usually around midday)
Spring / Autumn months: Either slightly before 11:00 am or just after 1:00 pm.
Duration of Sun Exposure
Fair skin: Depending on the region of Australia, during the summer months, the recommended duration of sun exposure is between 5 to 10 minutes each day and during the winter months the duration is between 7 to 30 minutes each day. View the Fair Skin Infographic here.
Darker skin: Depending on the region of Australia and the darkness of your skin, during the summer months, the recommended duration of sun exposure to produce sufficient vitamin D is between 15 to 60 minutes each day and during the winter months the duration could be as low as 20 minutes each day (if you live in Darwin) but as high as 3 hours of sun exposure if you live in Tasmania. We can’t imagine people in Tassie sitting on a cold and windy beach for three hours each day during winter, which is why Naturopathic Practitioners at Optimal Vitality will often recommend vitamin D supplementation, especially during winter, to ensure clients meet their recommended daily requirements of vitamin D each day. View the Dark Skin Infographic here.
Body Area Exposed
Expose larger areas of your skin to the sun, such as arms, legs or back (without sunscreen for several minutes but avoid burning), to increase vitamin D production. Face exposure alone is typically insufficient.
Geographic Region and Season
Closer to the equator: People living closer to the equator need less time in the sun year-round compared to those living farther away.
Summer months: Vitamin D synthesis is at its peak during the summer months, when vitamin D can be produced sufficiently in shorter periods. Excess vitamin D is stored in adipose cells (fat tissue) to be used during periods when vitamin D synthesis is insufficient.
Winter months: Vitamin D synthesis during winter months is significantly reduced, therefore longer exposure periods are required to produce sufficient vitamin D. Vitamin D supplementation or fortified dietary sources are regularly recommended during winter, specifically in cases where a recent blood test indicates sub-optimal vitamin D levels.
Use of Sunscreen
Sunscreen blocks UVB rays and thus inhibits vitamin D production.
Safe Sun Exposure
Balancing sun exposure for vitamin D synthesis involves understanding one’s skin type, optimal sun exposure times, and the duration required for adequate vitamin D production. Combining safe sun exposure practices with dietary sources and supplements, if necessary, should be deployed to maintain healthy vitamin D levels while minimising the risk of skin damage and associated health risks.
Short and Frequent Exposure
Summer :For most people, adequate vitamin D levels are reached through regular incidental exposure to the sun. When the UV Index is 3 or above (such as during summer), most people maintain adequate vitamin D levels just by spending a few minutes outdoors on most days of the week.
Late autumn and winter: In late autumn and winter, in some southern parts of Australia, when the UV Index falls below 3, spend time outdoors in the middle of the day with arms and legs or your back uncovered. Being physically active outdoors (e.g. exercising, playing sports, a brisk walk, taking the kids to the park, walking the dog or gardening) also helps boost vitamin D levels.
Safest Time During the Day
Mid-morning or late afternoon: Safer times with lower UV intensity while still allowing for vitamin D synthesis.
Avoid peak UV hours during summer: If you are fair-skinned or have a high risk of skin cancer, avoid sun exposure between 10:00 am and 2:00 pm.
UV forecast: Check local weather conditions to avoid sun exposure when UV intensity is high.
Expose Larger Areas of Skin
Arms and legs or back: Maximising the exposed skin area helps produce more vitamin D in a shorter time.
Use Sunscreen Strategically
The Cancer Council of Australia recommends sun protection when the UV Index is 3 or above, or when spending extended periods of time outdoors. It also recommends incorporating sunscreen into your daily morning routine on these days.
Northern Australia: UV radiation levels in northern areas of Australia are generally higher than in southern areas, so in some parts of the country, sun protection is needed all year round, whenever the UV Index is 3 or higher. In these areas, it is safe to go outside without sun protection early morning and late afternoon when the UV Index falls below 3.
Southern Australia: In some southern areas of Australia, there are times of the year when sun protection may not be necessary, generally late autumn and winter. If you live in an area where the UV Index falls below 3 during these months, you do not require sun protection, unless you are at high altitudes or near highly reflective surfaces like snow, work outdoors, or are outside for extended periods.
Initial exposure: Allow brief, unprotected exposure to the sun for several minutes initially. Following the initial exposure period, apply sunscreen to protect your skin from excessive exposure, if staying outside longer.
SPF 30 or higher: For extended sun exposure, use broad-spectrum sunscreen to protect against both UVA and UVB rays.
To check UV levels and the times sun protection is required, view your local weather conditions using a respectable weather app or website. Or visit the Bureau of Meteorology website. You can also download the free SunSmart app to your mobile device, a resource provided by the Cancer Council of Australia. SunSmart allows users to view UV levels and issues alerts when UV levels are higher than 3 (no UV alert is issued when UV levels are below 3).
Additional Protection Strategies
Protective Clothing
Hats and sunglasses: To protect face and eyes.
Cover limbs: Wear long-sleeved shirts and pants made of tightly woven fabric during extended sun exposure.
Seek Shade
Direct sun exposure / high UV index: Seek shade during peak UV hours to reduce direct sun exposure.
Remember the SunSmart Slogan
The Cancer Council of Australia’s slogan for its SunSmart Campaign:
Slop: Slop on sunscreen
Slap: Slap on a cap or hat
Seek: Seek shade
Slide: Slide on some sunglasses.
Regular Skin Checks
Self-examinations: Regularly check the skin for new moles or changes to existing moles.
Dermatologist visits: Annual skin exams for early detection of skin cancer.
Periodic Blood Tests
Medical doctors may request periodic blood tests to determine vitamin D levels in people with previously low vitamin D levels and/or chronic vitamin D deficiency and/or displaying signs and symptoms of vitamin D deficiency.
Alternative Vitamin D Sources
Dietary Sources
Fatty fish: Salmon, mackerel, and sardines.
Mushrooms: Culinary mushrooms synthesise vitamin D when their gills are exposed to sunlight.
Egg yolks: Contain small amounts of vitamin D.
Fortified foods: Milk, orange juice, and cereals.
Supplements
Vitamin D supplements: Especially useful during winter months or for individuals with limited sun exposure. Supplements come in several forms including capsules, drops and sprays. Consult with a healthcare provider for the appropriate dosage.
Summary
Ultraviolet radiation from the sun is the best source of vitamin D but also a major cause of skin cancer. In Australia, a delicate balance is required to harness the health benefits of adequate vitamin D levels produced by skin exposure to sunlight and the risk of skin cancer from too much sun exposure. Safe sun exposure, including sensible sun protection encourages vitamin D synthesis to increase or maintain adequate levels while reducing the risk of skin damage and skin cancer. Summarised factors involve:
Understanding your skin type and geographic location.
Limiting unprotected sun exposure to brief periods, especially around midday.
Using protective clothing and sunscreen during extended outdoor activities.
Considering alternative sources of vitamin D through diet and supplements.
Regular skin checks to monitor for signs of skin cancer.
By following these guidelines, adequate vitamin D levels can be maintained safely while protecting the skin from potential damage.
The information provided on this website is intended for general informational purposes only. It is not intended to be a substitute for professional medical advice.
Schedule an appointment with a Naturopathic Practitioner at Optimal Vitality to learn more about how naturopathy can support you on your health journey.