Health Education: Vitamin D

Vitamin D

Vitamin D - Health Professional Fact Sheet:

Vitamin D is a fat-soluble vitamin that is naturally present in very few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis.

Vitamin D

Vitamin D is a group of fat-soluble sec steroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and multiple other biological effects. In humans, the most important compounds in this group are vitamin D₃ and vitamin D₂.

Vitamin D

The Benefits of Vitamin D

Sunshine vitamin

Vitamin D is sometimes called the “sunshine vitamin” because it’s produced in your skin in response to sunlight. It’s a fat-soluble vitamin in a family of compounds that includes vitamins D-1, D-2, and D-3.

Your body produces vitamin D naturally when it’s directly exposed to sunlight. You can also get it through certain foods and supplements to ensure adequate levels of the vitamin in your blood.

Vitamin D has several important functions. Perhaps the most vital are regulating the absorption of calcium and phosphorus and facilitating normal immune system function. Getting a sufficient amount of vitamin D is important for normal growth and development of bones and teeth, as well as improved resistance against certain diseases.

If your body doesn’t get enough vitamin D, you’re at risk of developing bone abnormalities such as soft bones (osteomalacia) or fragile bones (osteoporosis).

Here are three more surprising benefits of vitamin D.

1. Vitamin D fights disease

In addition to its primary benefits, research suggests that vitamin D may also play a role in:

Reducing your risk of multiple sclerosis, according to a 2006 study published in the Journal of the American Medical Association
Decreasing your chance of developing heart disease, according to 2008 findings published in Circulation Trusted Source
Helping to reduce your likelihood of developing the flu, according to 2010 research published in the American Journal of Clinical Nutrition

2. Vitamin D reduces depression

Research has shown that vitamin D might play an important role in regulating mood and warding off depression. In one study, scientists found that people with depression who received vitamin D supplements noticed an improvement in their symptoms.

In another study of people with fibromyalgia, researchers found vitamin D deficiency was more common in those who were also experiencing anxiety and depression.

3. Vitamin D boosts weight loss

Consider adding vitamin D supplements to your diet if you’re trying to lose weight or prevent heart disease. You can find a great selection of vitamin D supplements on Amazon.com.

In one study, people taking daily calcium and vitamin D supplement were able to lose more weight than subjects taking a placebo supplement. The scientists said the extra calcium and vitamin D had an appetite-suppressing effect.

In another study, overweight people who took a daily vitamin D supplement improved their heart disease risk markers.

Beware of Deficiency

Many factors can affect your ability to get sufficient amounts of vitamin D through the sun alone. These factors include:

Being in an area with high pollution
Using sunscreen
Spending more time indoors
Living in big cities where buildings block sunlight
Having darker skin. (The higher the levels of melanin, the less vitamin D the skin can absorb.)

These factors contribute to vitamin D deficiency in an increasing number of people. That’s why it’s important to get some of your vitamin D from sources besides sunlight.

The symptoms of a vitamin D deficiency in adults include:

Tiredness, aches and pains, and a general sense of not feeling well
Severe bone or muscle pain or weakness that may cause difficulty climbing stairs or getting up from the floor or a low chair, or cause you to walk with a waddling gait
Stress fractures, especially in your legs, pelvis, and hips

Doctors can diagnose a vitamin D deficiency by performing a simple blood test. If you have a deficiency, your doctor may order X-rays to check the strength of your bones.

If you’re diagnosed with a vitamin D deficiency, your doctor will likely recommend you take daily vitamin D supplements. If you have a severe deficiency, they may instead recommend high-dose vitamin D tablets or liquids. You should also make sure to get vitamin D through sunlight and the foods you eat.

Food sources of vitamin D

Few foods contain vitamin D naturally. Because of this, some foods are fortified. This means that vitamin D has been added. Foods that contain vitamin D include:

Salmon
Sardines
Egg yolk
Shrimp
Milk (fortified)
Cereal (fortified)
Yogurt (fortified)
Orange juice (fortified)

It can be hard to get enough vitamin D each day through sun exposure and food alone, so taking vitamin D supplements can help.

How much do you need?

There has been some controversy over the amount of vitamin D needed for healthy functioning. Recent research indicates that you need more vitamin D than was once thought. Normal blood serum levels range from 50 to 100 micrograms per deciliter. Depending on your blood level, you may need more vitamin D.

The Institute of Food and Agricultural Sciences reports new recommendations based on international units (IUs) per day. IUs are a standard type of measurement for drugs and vitamins. IUs help experts determine the recommended dose, toxicity, and deficiency levels for each person.

One IU is not the same for each type of vitamin. An IU is determined by how much of a substance produces an effect in your body. The recommended IUs for vitamin D are:

Children and teens: 600 IU
Adults up to age 70: 600 IU
Adults over age 70: 800 IU
Pregnant or breastfeeding women: 600 IU

Vitamin D Deficiency

Getting enough, but not too much, vitamin D is needed to keep your body functioning well. Vitamin D helps with strong bones and may help prevent some cancers. Symptoms of vitamin D deficiency can include muscle weakness, pain, fatigue, and depression. To get enough D, look to certain foods, supplements, and carefully planned sunlight.

What is vitamin D deficiency?

Vitamin D deficiency means that you do not have enough vitamin D in your body. Vitamin D is unique because your skin actually produces it by using sunlight. Fair-skinned individuals and those who are younger convert sunshine into vitamin D far better than those who are darker-skinned and over age 50.

Why is vitamin D so important?

Vitamin D is one of many vitamins our bodies need to stay healthy. This vitamin has many functions, including:

Keeping bones strong: Having healthy bones protects you from various conditions, including rickets. Rickets is a disorder that causes children to have bones that are weak and soft. It is caused by a lack of vitamin D in the body. You need vitamin D so that calcium and phosphorus can be used to build bones. In adults, having soft bones is a condition called osteomalacia.

Absorbing calcium: Vitamin D, along with calcium, helps build bones and keep bones strong and healthy. Weak bones can lead to osteoporosis, the loss of bone density, which can lead to fractures. Vitamin D, once either taken orally or from sunshine exposure is then converted to an active form of the vitamin. It is that active form that promotes optimal absorption of calcium from your diet.
Working with parathyroid glands: The parathyroid glands work minute to minute to balance the calcium in the blood by communicating with the kidneys, gut, and skeleton. When there is sufficient calcium in the diet and sufficient active Vitamin D, dietary calcium is absorbed and put to good use throughout the body. If calcium intake is insufficient, or vitamin D is low, the parathyroid glands will ‘borrow’ calcium from the skeleton in order to keep the blood calcium in the normal range.

What are the health effects of vitamin D deficiency?

Getting enough vitamin D may also play a role in helping to keep you healthy by protecting against the following conditions and possibly helping to treat them. These conditions can include:

Heart disease and high blood pressure.
Diabetes.
Infections and immune system disorders.
Falls in older people.
Some types of cancer, such as colon, prostate and breast cancers.
Multiple sclerosis.

What are the sources of vitamin D?

You can get vitamin D in a variety of ways. These can include:

Being exposed to the sun. About 15-20 minutes three days per week is usually sufficient.
Through the foods, you eat.
Through nutritional supplements.

What does sunlight have to do with getting enough vitamin D?

Vitamin D is produced when your skin is exposed to sunshine, or rather, the ultraviolet B (UV-B) radiation that the sun emits. The amount of vitamin D that your skin makes depends on such factors as:

The season: This factor depends a bit on where you live. In areas such as Cleveland, OH, the UV-B light does not reach the earth for six months out of the year due to the ozone layer and the zenith of the sun

The time of day: The sun's rays are most powerful between 10 a.m. and 3 p.m.
The amount of cloud cover and air pollution.
Where you live: Cities near the equator have higher ultraviolet (UV) light levels. It is the UV-B light in sunlight that causes your skin to make vitamin D.
The melanin content of your skin: Melanin is a brown-black pigment in the eyes, hair, and skin.
Melanin causes the skin to tan. The darker your skin, the more sun exposure is needed in order to get sufficient vitamin D from the sun.

What does your diet have to do with getting enough vitamin D?

Vitamin D doesn’t occur naturally in many foods. That’s why certain foods have added vitamin D. In fact, newer food nutrition labels show the amount of vitamin D contained in a particular food item.

It may be difficult, especially for vegans or people who are lactose-intolerant, to get enough vitamin D from their diets, which is why some people may choose to take supplements. It is always important to eat a variety of healthy foods from all food groups. The vitamin content of various foods is shown in the following table.

Vitamin D content of various foods

S.No.	Vitamin D content in International	Units (IUs) per serving
1	Cod liver oil, 1 tablespoon	1360
2	Swordfish, cooked, 3 ounces	566
3	Salmon (sockeye) cooked, 3 ounces	447
4	Tuna, canned in water, drained, 3 ounces	154
5	Orange juice fortified with vitamin D, 1 cup	137
6	Milk, vitamin-fortified, 1 cup	115-124
7	Yogurt, fortified with 20% of the daily value of vitamin D, 6 ounces	80
8	Sardines, canned in oil, drained, 2 sardines	46
9	Liver, beef, cooked, 3 ounces	42
10	Egg yolk, 1 large	41
11	Cereal, fortified with 10% of the daily value of vitamin D, 1 cup	40
12	Cheese, Swiss, 1 ounce	6

Source: Vitamin D. Health Professionals. Dietary Supplement Fact Sheet. National Institutes of Health. Office of Dietary Supplements. August 7, 2019.

It is important to check product labels, as the amount of added vitamin D varies when it is artificially added to products such as orange juice, yogurt, and margarine.

How much vitamin D do you need?

In healthy people, the amount of vitamin D needed per day varies by age. The chart below shows the often-cited recommendations of the Institute of Medicine, now the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine. It is important to know that these are general recommendations. If your doctor is checking your blood levels, he or she might recommend higher or lower doses based on your individual needs.

If you have osteoporosis, your doctor might suggest a blood test of your vitamin D levels. The amount of vitamin D supplement can be customized for each person, based on the results. For many older patients, a vitamin D supplement containing anywhere between 800 to 2000 IUs daily, which can be obtained without a prescription, can be both safe and beneficial. It is important to speak with your doctor about your individual needs.

S.No.	People by age	Recommended dietary allowance (IU/day)	Upper level intake (IU/day)
1	Infants 0-6 months*	400	1,000
2	Infants 6-12 months*	400	1,500
3	Children 1-3 years old	600	2,500
4	Children 4-8 years old	600	3,000
5	People 9-70 years old	600	4,000
6	People over 70 years old	800	4,000
7	Females 14-50 years old, pregnant/lactating	600	4,000

*refers to adequate intake vs recommended dietary allowance of the other age groups.

What causes vitamin D deficiency?

Vitamin D deficiency can be caused by specific medical conditions, such as:

Cystic fibrosis, Crohn's disease, and celiac disease: These diseases do not allow the intestines to absorb enough vitamin D through supplements.
Weight loss surgeries. Weight loss surgeries that reduce the size of the stomach and/or bypass part of the small intestines make it very difficult to consume sufficient quantities of certain nutrients, vitamins, and minerals. These individuals need to be carefully monitored by their doctors and need to continue to take vitamin D and other supplements throughout their lives.
Obesity: A body mass index greater than 30 is associated with lower vitamin D levels. Fat cells keep vitamin D isolated so that it is not released. Vitamin D deficiency is more likely in obese people. Obesity often makes it necessary to take larger doses of vitamin D supplements in order to reach and maintain normal D levels.
Kidney and liver diseases: These diseases reduce the amount of an enzyme needed to change vitamin D to a form that is used in the body. Lack of this enzyme leads to an inadequate level of active vitamin D in the body

What other factors can lead to vitamin D deficiency?

Age: The skin's ability to make vitamin D lessens with age.
Mobility: People who are homebound or are rarely outside (for example, people in nursing homes and other facilities) are not able to use sun exposure as a source of vitamin D.
Skin color: Dark-colored skin is less able to make vitamin D than fair-colored skin.
Human breast milk: A woman's breast milk only contains a small amount of vitamin D. Often infant formulas also only include a small amount of D also. Therefore infants are at risk of not receiving enough vitamin D. This is especially true for infants who are only fed breast milk.

Can medications cause a vitamin D deficiency?

Yes. Vitamin D levels can be lowered by certain medications. These include:

Laxatives.
Steroids (such as prednisone).
Cholesterol-lowering drugs (such as cholestyramine and colestipol).
Seizure-control drugs (such as phenobarbital and phenytoin).
A tuberculosis drug (rifampin).
A weight-loss drug (orlistat).

Always tell your doctor about the drugs you take and any vitamin D supplements or other supplements or herbs/alternative health products that you take.

What are the signs and symptoms of vitamin D deficiency?

Severe lack of vitamin D causes rickets, which shows up in children as incorrect growth patterns, weakness in muscles, pain in bones, and deformities in joints. This is very rare. However, children who are deficient in vitamin D can also have muscle weakness or sore and painful muscles.

Lack of vitamin D is not quite as obvious in adults. Signs and symptoms might include: