When winter comes, thick fog, low temperatures and short sunshine make many people less likely to go out. This reduces the ability to expose to sunlight, an important natural source that helps the body produce vitamin D. Meanwhile, vitamin D deficiency is a common problem, directly affecting bones, immunity and overall health.
According to Dr. Basavaraj S. Kumbar, a medical consultant at Aster Whitefield Hospital (Bengaluru, India), sunlight can still help the body produce vitamin D in winter, but it is necessary to be exposed at the right time and enough time. The reason is that in the cold season, the intensity of UVB rays, the type of rays needed to synthesize vitamin D, decreases significantly compared to summer.
Experts say that the best time to absorb vitamin D from winter sunlight is from about 11 am to 2 pm. During this time frame, the sun is higher, UVB rays shine down with enough intensity to activate the process of vitamin D synthesis through the skin. Conversely, early morning and late afternoon sunlight are often weak, UVB rays are absorbed by the atmosphere a lot, so the effectiveness is low.
Regarding the exposure time, Dr. Kumbar recommends that each person should be exposed to direct sunlight for 20 to 40 minutes in winter, depending on skin color and weather conditions. Skin areas such as the face, arms or calves need to be exposed to direct sunlight, not through glass doors and not covered by thick clothes. Sunlight through glass does not help the body synthesize vitamin D.
Skin color is also a significant factor. People with bright skin usually only need about 15-20 minutes of sun exposure, while people with average or dark skin may need up to 30-45 minutes. The reason is that melanin in the skin acts as an ultraviolet filter, slowing down the vitamin D synthesis process.
In winter, many other factors also reduce the ability to produce vitamin D, including fog, air pollution and excessive indoor habits. Elderly people, people working in offices or living in sunny areas are at higher risk of vitamin D deficiency.
To support the body, experts recommend supplementing with vitamin D-rich foods in your daily diet, such as fatty fish, egg yolks, milk and fortified cereals, mushrooms. In case of severe deficiency, doctors may prescribe vitamin D supplementation, usually vitamin D3.
Vitamin D plays an important role in calcium absorption, maintaining bone health, strengthening immunity and supporting mood. Although winter makes vitamin D absorption more difficult, if sunbathing is done at the right time, enough time and combined with a reasonable diet, the body can still maintain the necessary vitamin D levels safely.
