Check out this answer from Consensus:
While sun exposure is a significant source of vitamin D, it may not always be sufficient to maintain optimal levels, even in sunny climates. Factors such as lifestyle, seasonal variations, and individual health conditions can contribute to vitamin D deficiency. Therefore, supplementation is often recommended to ensure adequate vitamin D levels, particularly for high-risk groups. Regular monitoring and appropriate dosage adjustments are essential to achieve and maintain optimal vitamin D status.
Vitamin D is essential for maintaining bone health and supporting the immune system. It is primarily obtained through sun exposure, which triggers its synthesis in the skin. However, even in sunny climates, vitamin D deficiency can still be prevalent. This article explores whether individuals living in sunny regions need vitamin D supplements, drawing on recent research findings.
The Role of Sunshine in Vitamin D Synthesis
Sunshine is a critical determinant of vitamin D status. A study on Crohn’s disease patients found that both sunshine and supplementation significantly influenced vitamin D levels. Even among those taking high-dose supplements, sunshine remained a vital factor in maintaining adequate vitamin D levels1. This suggests that while sun exposure is beneficial, it may not always be sufficient.
Vitamin D Deficiency in Sunny Climates
Contrary to common belief, living in a sunny climate does not guarantee sufficient vitamin D levels. Research conducted in a luminous climate revealed that 14% of children had vitamin D levels below 20 ng/mL, and 49% had levels below 30 ng/mL, which are considered insufficient3. This indicates that lifestyle factors, such as indoor activities and sun avoidance, can lead to deficiencies even in sunny regions.
Supplementation Recommendations
Various guidelines recommend vitamin D supplementation, especially for individuals with limited sun exposure. For instance, elderly individuals and those who avoid the sun are advised to take supplements to meet their vitamin D requirements2. A study in Australia found that adding vitamin D to calcium supplementation had long-term benefits on bone density in elderly women, highlighting the importance of supplementation even in sunny climates5.
Seasonal Variations and Supplementation
Seasonal variations can also affect vitamin D levels. A study in the UK showed that holidays in sunny destinations and the use of cod liver oil supplements helped reduce vitamin D deficiency during winter months4. This underscores the need for supplementation during periods of low sun exposure, even for those living in generally sunny areas.
Optimal Supplementation Dosage
Determining the optimal dosage of vitamin D supplements is crucial. A study in a sunny country found that a daily dose of 400 IU was insufficient to achieve optimal vitamin D levels in postmenopausal women with osteoporosis6. This suggests that higher doses may be necessary to maintain adequate levels, especially for those at risk of deficiency.
Do we need vitamin D supplements if we live in a sunny place?
Peter McCaffery has answered Unlikely
An expert from University of Aberdeen in Biochemistry
You will know that we can synthesize our own vitamin D so not needed if live in a sunny place – but there are lots of caveats – you have to be exposed to the sun and if spend a lot of time indoors, or worried about the very real detrimental effects of sunlight to cause skin cancer, may not be exposed sufficiently (would you believe even in Australia https://bmjopen.bmj.com/content/10/3/e032567). Further an individual may have some genetic changes that makes them more susceptible to deficiency. Thus, although vitamin D deficiency will certainly be a lot rarer in a sunny place it may not be absent.
Do we need vitamin D supplements if we live in a sunny place?
Carol Haggans has answered Uncertain
An expert from National Institutes of Health in Nutrition, Dietetics
Most people meet at least some of their vitamin D needs through sun exposure. However, the amount of vitamin D someone makes from sun exposure depends on a number of factors including season, time of day, length of day, cloud cover, and smog. In addition, older people and people with dark skin are less able than others to produce vitamin D from sunlight. Health experts recommend using sunscreen to reduce the risk of skin cancer, but sunscreen does limit vitamin D production. It’s difficult to know how much vitamin D someone is getting from sun exposure, but as a general rule, approximately 5–30 minutes of sun exposure, particularly between 10 a.m. and 4 p.m., either daily or at least twice a week to the face, arms, hands, and legs without sunscreen usually leads to sufficient vitamin D synthesis. Doctors can test vitamin D levels in the blood to see if they are within a normal range.