From the Guidelines
Sunscreen does not typically cause vitamin D deficiency with normal use, as most people do not apply enough sunscreen to completely block UVB rays, allowing for some vitamin D production to occur. When applied correctly, sunscreen blocks the UVB rays that both cause sunburn and trigger vitamin D synthesis in the skin. However, a study found that sunscreen use over the summer had no effect on 25-hydroxyvitamin D3 levels in people over 40 years of age 1. Some key points to consider include:
- Brief sun exposure of face, arms, and hands (about 10-15 minutes several times a week) before applying sunscreen is sufficient for vitamin D production, especially during summer months.
- Those at risk for deficiency—including people with darker skin, older adults, those who cover their skin for religious or cultural reasons, or people living in northern latitudes—may need vitamin D supplements (typically 600-800 IU daily for adults).
- The benefits of sunscreen in preventing skin cancer and premature aging outweigh concerns about vitamin D, and any potential reduction can be easily addressed through diet (fatty fish, fortified dairy products, eggs) or supplements if needed. Some concerns related to sun avoidance include reduced physical activity levels among children and negative effects on mental health, but no studies have evaluated the effects of sun protection behaviors on these outcomes 1.
From the Research
Sunscreen and Vitamin D
- The relationship between sunscreen use and vitamin D levels has been investigated in several studies 2, 3, 4, 5, 6.
- While sunscreen use can prevent skin cancer, there are concerns that it may increase the risk of vitamin D deficiency 3.
- However, the weight of evidence from field trials and observational studies suggests that the risk of vitamin D deficiency due to sunscreen use is low 3.
- Sunscreen use can block the ability of the skin to photosynthesize vitamin D, but the effect this has on the vitamin D status of the general population is unclear 5.
Factors Affecting Vitamin D Production
- Latitude, season, skin color, and sun protection determine UV absorption and vitamin D production 2.
- Skin pigment, sunscreen use, aging, time of day, season, and latitude dramatically affect previtamin D3 synthesis 4, 6.
- Vitamin D deficiency can be caused by inadequate fortification of foods with vitamin D and the misconception that a healthy diet contains an adequate amount of vitamin D 4, 6.
Health Consequences of Vitamin D Deficiency
- Vitamin D deficiency can increase chronic diseases and cancer, while adequate vitamin D levels can help prevent them 2.
- Vitamin D deficiency causes growth retardation and rickets in children and will precipitate and exacerbate osteopenia, osteoporosis and increase risk of fracture in adults 4, 6.
- The vitamin D deficiency pandemic has other serious consequences including increased risk of common cancers, autoimmune diseases, infectious diseases, and cardiovascular disease 4, 6.