What is the optimal time to stay out in the sun?

Sun exposure is not as bad as you might think. There may be many assumptions that state that exposure to the hot sun can cause skin cancer and various other skin diseases. But did you know that 90% of the vitamin D needed by the body comes from sunlight?

What does vitamin D do?

Vitamin D is a fat soluble vitamin that is needed for health, especially bone health. This vitamin, which is often called the sun vitamin, functions to increase the absorption of calcium which is good for bone health, keeps calcium and phosphorus levels normal, increases bone cell growth, and relieves inflammation when an infection occurs in the body.

According to Harvard University, an estimated 1 billion people are deficient in vitamin D. Other studies have found that vitamin D can also prevent breast cancer, multiple sclerosis, and schizophrenia. From The Archive of Internal Medicine, it is known that people who have low levels of vitamin D, have a risk of dying 2 times higher due to various heart diseases. Even research conducted in Canada states that vitamin D deficiency is associated with the incidence of breast cancer in women.

Not only that, research reported in the Archives of General Psychiatry found an association of vitamin D deficiency with increased depression in women and men aged 65 to 95 years. The average amount of vitamin D needed by the body is 15 mcg per day and for people over 65 years old, it requires 25 mcg of vitamin D per day.

How does sunlight stimulate the body to produce vitamin D?

The body is designed to produce vitamin D automatically when the skin is exposed to sunlight. Sunlight contains ultraviolet B (UVB) rays. When UV B is exposed to the skin, the skin will form vitamin D3 (cholecalciferol) in large quantities. Vitamin D3 is the previtamin from vitamin D which will be distributed directly to the liver and kidneys to produce vitamin D needed by the body.

Actually, it doesn't take a long time of exposure to sunlight for the skin to form vitamin D3, even only 15 minutes for people with white skin. Meanwhile, people who have dark skin types take longer, about 90 minutes. However, you don't have to burn your skin for hours to get vitamin D. Skin that is exposed to the sun for a short period of time can produce the amount of vitamin D your body needs for its daily needs.

What affects the amount of vitamin D produced during sunbathing?

Basically, your body can produce 250 mcg to 625 mcg in a short time, depending on the skin color and the clothes you wear. The more parts of the skin that are exposed to the sun, the more vitamin D the body will produce. The following are some of the factors that affect the amount of vitamin D produced:

1. When exposed to sunlight

The time to absorb sunlight greatly affects the amount of vitamin D the body will produce. When it is in the morning or evening, usually the atmosphere blocks the sunlight so that UV B rays cannot penetrate and do not hit the skin. During the day, the more vitamin D is produced. Simply put, the higher the shade you have, the less vitamin D will be generated, and vice versa.

2. Skin color

Melanin is a substance that affects a person's skin color. The more melanin you have, the darker your skin will be. The amount of melanin also determines the amount of vitamin D the body can produce. The function of melanin is to protect the skin from damage that can be caused by too much UVB exposure, so that dark skin contains a lot of melanin and blocks UVB rays from being absorbed by the skin. Little UVB rays are absorbed causing a low production of vitamin D. That is why, if you have dark skin, then you need more time to be exposed to sunlight for the body to produce vitamin D.

People who are white, may only need 15 minutes of sun exposure. Meanwhile, a person with darker skin takes at least 6 times longer than a white person.

3. Other factors

Other factors that affect the production of vitamin D from sunlight include:

• How many parts of the body are exposed to the sun.
• Age. The older you get, the lower your ability to produce vitamin D.
• Location. The sunshine actually has better quality the higher the location. Your skin will easily build up vitamin D from the sun if you are in a mountainous area rather than a beach.
• Cloudy weather prevents UVB rays from hitting your skin.
• Air pollution can cause UVB rays to reflect off of your skin. So if you live in a place that has high air pollution, you may be deficient in vitamin D because air pollution blocks UVB rays.

Who is at risk for vitamin D deficiency?

Some people may be at risk for vitamin D deficiency because they are not exposed to sunlight, so no vitamin D builds up. These people are:

• People who have dark skin. This group needs more UV light to produce vitamin D.
• The elderly or elderly who spend most of their time indoors.
• Babies whose mothers are deficient in vitamin D during pregnancy.
• Take several medications that affect the production of vitamin D and calcium.
• Groups that do need to avoid the sun, such as people who have a history of skin cancer.

These groups usually need vitamin D supplements to support their daily needs. In addition, groups who are at risk of experiencing vitamin D deficiency are encouraged to consume various food sources that contain vitamin D such as milk, fish fat in tuna and salmon, beef liver, egg yolks, and cereals.