Vitamin D is important for health. Humans tend to think that they get enough of it from the sunlight. That, however, is not true for everyone. Many people require supplements to fulfill their body's need for Vitamin D. Today we are going to talk about the importance of this Vitamin, whether sunlight is enough for completing body's need for it and what other sources it can be found in.
Medicine Net describes vitamin D as "A steroid vitamin which promotes the intestinal absorption and metabolism of calcium and phosphorus." Vitamin D is produced in the skin and the production depends on the exposure to sunlight.
Vitamin D helps the body absorb calcium for stronger bones and supports the immune system in fighting diseases. It helps the nerves carry messages to and from the brain and also helps in the muscle movements of the body. Vitamin D, when processed, turns into a hormone calcitriol- which helps the bones absorb calcium.
Many people are able to get enough vitamin D from the sunlight but it totally depends on their geographical location, what time of the year it is, what time of the day they are exposed to the sunlight and what their skin color is.
People living nearer to the equator naturally are exposed to more sunlight. In the Northern Hemisphere, a person's requirement of sunlight might not be met in the winters.
In summers, a person need not be out in the sun for long to get enough vitamin D. The sun is the fiercest between 11 am to 3 pm.
According to the Medicine Net, Melanin is "the pigment that gives human skin, hair, and eyes their color. Dark-skinned people have more melanin in their skin than light-skinned people have." The amount of vitamin D a person makes depends on the amount of melanin in their skin.
Lighter skin is the result of less melanin which does not protect so well against the damaging ultraviolet (UV) rays of the sun. On the other hand, people who have more melanin in their skin get better protection against the UV rays but their bodies take longer to produce vitamin D.
These diverse factors make it tough to recommend the correct amount of sunlight for vitamin D to a person. To prove this the Vitamin D council gives a few examples-
"At noon during summer in Miami, someone with a medium skin tone would need to expose one-quarter of their skin to sunlight for 6 minutes."
"At noon during summer in Boston, someone with a darker skin tone would need to expose one-quarter of their skin to sunlight for 2 hours."
Bodies of some people might not be able to receive enough vitamin D from the sunlight because of a certain kind of lifestyle. For example, people who work night shifts and are at home the entire day or keep their skins covered all the time and use high SPF sunscreen are prone to have bodies deficient in vitamin D.
Overexposing one's skin to sunlight can also be harmful. The body needs only a limited amount of vitamin D and beyond that skin should be protected from the harmful UV rays which can cause aging of the skin, burning and also increase the risk of skin cancer. But what happens if the body is deficient in vitamin D?
There is no official set level of vitamin D deficiency. To measure the amount of vitamin D in the blood, scientists use nanograms per millimeter (ng/mL). Some consider that if the blood has less than 12 ng/mL of vitamin D the body is deficient and if the amount is less than 20 ng/mL then it is a red alert.
Another group believes that the amount should be higher and alarm bells should ring in case it is less than 30 ng/mL.
In children the deficiency of vitamin D causes rickets. In this condition, the bones of the body become soft and bend. In the case of adults, the deficiency can also cause bones to pain and muscles to weaken.
If there is a chronic deficiency of this vitamin it can lead to osteoporosis. Medicine Net defines Osteoporosis as "a condition of fragile bone with an increased susceptibility to fracture."
As mentioned earlier, a specific recommendation for vitamin D intake is hard to suggest because of all the varying factors of location, season and time. However, the guidelines are based on the assumption that a person gets minimum sun.
Given below is the chart recommended by the Food and Nutrition Board for the minimum intake of vitamin D to keep the body healthy. The intake is given in Internation Units (IU).
| Age | Recommended daily intake of vitamin D |
| 0 to 12 months | 400 IU |
| 1 to 70 years | 600 IU |
| 70 years and above | 800 IU |
The Endocrine Society recommends a daily consumption of 1,500–2,000 IU to adults whose vitamin D levels are below 30 ng/mL, to restore healthy levels. If a person goes for a treatment then instead of daily consumption, they are given a dosage of 50,000 IU weekly or monthly.
Here is a good news for cheese lovers- cheese is an organic source of vitamin D. Other natural sources are:
In the U.S, vitamins are artificially added in some food items which are called to be fortified. For example- milk, breakfast cereals, orange juice etc- can be often found to contain vitamin D and it is always mentioned on the nutrition label what foods contain what vitamins.
Breast milk does not contain enough vitamin D that is needed for an infant's healthy growth, therefore breastfed babies require vitamin D supplements. This can be easily done as vitamin D drops are accessible over-the-counter (OTC). Also, the formula that is used to feed babies also has enough vitamin D.
Excess of anything is bad and it holds true for vitamin D also. The body cannot prepare too much vitamin D from exposure to the sun; it is usually the result of supplements. It is rare though and is known to occur when someone takes very high doses for a long period of time (like over a year).
As long as a person is not exceeding the intake of 4,000 IU daily it is fine but daily intake of more than this can lead to symptoms like:
Excess of vitamin D in the body means excessive calcium in the blood- this can cause problems like that of heart and mental confusion.
If you are on some specific medication, you should not take vitamin D supplement without consulting your doctor as it can interfere with the working of the medicine.
If vitamin D deficiency is observed then the doctor first takes a blood test to measure the vitamin D levels.
If there is too much intake of the vitamin then the person might have symptoms of vitamin D toxicity- in this case too medical help should be sought.
Get enough sunlight and if that is not possible take enough supplements. Do not exceed either.