Why is vitamin d produced by the body

Absorbing sunlight is essential for the skin to produce vitamin D. Covering the skin with clothing can inhibit vitamin D production also. Geographical location: People who live in northern latitudes or areas of high pollution, work night shifts, or are homebound should aim to consume vitamin D from food sources whenever possible. Breastfeeding: Infants who exclusively breastfeed need a vitamin D supplement, especially if they have dark skin or have minimal sun exposure.

The American Academy of Pediatrics recommend that all breastfed infants receive international units IU per day of oral vitamin D. Supplement drops for babies are available online. Although people can take vitamin D supplements, it is best to obtain any vitamins or minerals through natural sources wherever possible. Read more on vitamin D deficiency. If Vitamin D deficiency continues for long periods, it may result in complications , such as:.

Getting sufficient sunlight is the best way to help the body produce enough vitamin D. Plentiful food sources of vitamin D include:. Here, learn how to get more vitamin D from the sun.

People can measure vitamin D intake in micrograms mcg or international units IU. One microgram of vitamin D is equal to 40 IU. The recommended daily intakes of vitamin D are as follows:. Sensible sun exposure on bare skin for 5—10 minutes, 2—3 times per week, allows most people to produce sufficient vitamin D. However, vitamin D breaks down quite quickly, meaning that stores can run low, especially in winter.

The upper limit that healthcare professionals recommend for vitamin D is 4, IU per day for an adult. Excessive consumption of vitamin D can lead to over calcification of bones and the hardening of blood vessels, kidney, lung, and heart tissues. The most common symptoms of excessive vitamin D include headache and nausea. However, too much vitamin D can also lead to the following:.

Excess vitamin D usually occurs from taking too many supplements. It is best to get vitamin D from natural sources. If someone is taking supplements, they should choose their brand carefully, as the FDA do not monitor the safety or purity of supplements.

Public Health England guidelines on vitamin D supplementation. About Contact Events News. Search Search. You and Your Hormones. Students Teachers Patients Browse. Human body. Home Hormones Vitamin D. Vitamin D Vitamin D is a hormone produced by the kidneys that helps to control the concentration of calcium in the blood and is vital for the development of strong bones.

Alternative names for vitamin D Calcitriol or 1,dihydroxyvitamin D ; ergocalciferol vitamin D 2 ; cholecalciferol vitamin D 3 ; calcidiol hydroxyvitamin D What is vitamin D? How is vitamin D controlled? What happens if I have too little vitamin D? What happens if I have too much vitamin D? The main requirement is to have enough vitamin D, but many Americans don't. Vitamin D deficiencies were rare when most men rolled up their sleeves to work in sunny fields.

But as work shifted from farms to offices, that changed. Deficiencies are also common in patients with intestinal disorders that limit absorption of fat and those with kidney or liver diseases that reduce the conversion of vitamin D to its active form, calcitriol 1,25 OH 2D.

In addition, certain medications reduce the availability or activity of vitamin D. And even in healthy people, advancing age is linked to an increased risk of vitamin D deficiency.

A number of factors can play a role. Limited exposure to sunlight heads the list. Except during the short summer months, people who live at latitudes above 37 degrees north or below 37 degrees south of the equator don't get enough UVB energy from the sun to make all the vitamin D they need. The same is true for people who spend most of their time indoors and for those of us who avoid sunshine and use sunscreens to protect our skin from the harmful effects of ultraviolet radiation see box below.

It's an example of an unforeseen consequence of wise behavior, but you can enjoy sun protection and strong bones, too, by taking vitamin supplements. Like politicians, doctors often have to compromise; when it comes to sunshine, most pols promise blue skies, while most docs turn out to be the shady guys — or, at least, sunscreen advocates. UVB provides the energy your skin needs to make vitamin D, but that energy can burn the skin and increase the cell damage that leads to cancer.

UVA also contributes to skin damage and premature aging. To protect yourself, avoid the summer sunshine, especially between 10 a. Whenever possible, wear a large-brimmed hat and a tightly woven, dark-colored long-sleeve shirt and long pants when you go out in the sun. But summer garb is usually lightweight and exposes a lot of skin. That's where a sunscreen comes in. Look for a product with an SPF of 30 or higher.

Apply your sunscreen early, often, and liberally. These many factors explain why vitamin D deficiencies are shockingly common in the United States. And low levels of vitamin D are common even in apparently healthy young adults; in one study, more than a third of people between the ages of 18 and 29 were deficient. Numbers can never tell the whole story, but in this case, "D-ficiencies" add up to a wide range of health concerns.

It's a paradox: Skeletal health is the best-known contribution of vitamin D, but it has also become the most controversial. Although doctors agree that vitamin D deficiency increases the risk of osteoporosis and fractures, they disagree about the benefits and optimal dosage of supplements.

Without enough vitamin D, the intestines cannot efficiently absorb calcium. But because blood calcium is critical for neuromuscular and cardiac function, the body does not allow levels to fall. Instead, it pours out parathyroid hormone, which mobilizes calcium from bone. Blood calcium levels remain normal, so your heart and nerves keep working nicely. But your bones bear the brunt: As bone calcium density falls, bones become weak and fracture-prone. Most studies show that a lack of vitamin D increases the risk of osteoporosis and the likelihood of hip and other non-spinal fractures.

But there is considerable disagreement about how much supplements reduce the risk of fractures. Some studies include only women, others both men and women; some include only frail, elderly, or institutionalized subjects, others physically active people; some use vitamin D alone, others a combination of D and varying doses of calcium; and some administer international units IU of vitamin D a day, others up to IU a day.

Some men mistakenly dismiss osteoporosis as a women's worry, but none fail to recognize the importance of prostate cancer.