osteomalacia

Vitamin D deficiency means that your body is not getting enough vitamin D to stay healthy.

Vitamin D helps your body absorb calcium. Calcium is one of the main building blocks of bone. Vitamin D also has a role in your nervous, muscle, and immune systems.

You can get vitamin D in three ways: through your skin, from your diet, and from supplements. Your body forms vitamin D naturally after exposure to sunlight. But too much sun exposure can lead to skin aging and skin cancer, so many people try to get their vitamin D from other sources.

The amount of vitamin D you need each day depends on your age. The recommended amounts, in international units (IU), are:

• Birth to 12 months: 400 IU
• Children 1-13 years: 600 IU
• Teens 14-18 years: 600 IU
• Adults 19-70 years: 600 IU
• Adults 71 years and older: 800 IU
• Pregnant and breastfeeding women: 600 IU

People at high risk of vitamin D deficiency may need more. Check with your health care provider about how much you need.

You can become deficient in vitamin D for different reasons:

• You don't get enough vitamin D in your diet
• You don't absorb enough vitamin D from food (a malabsorption problem)
• You don't get enough exposure to sunlight
• Your liver or kidneys cannot convert vitamin D to its active form in the body
• You take medicines that interfere with your body's ability to convert or absorb vitamin D

Some people are at higher risk of vitamin D deficiency:

• Breastfed infants, because human milk is a poor source of vitamin D. If you are breastfeeding, give your infant a supplement of 400 IU of vitamin D every day.
• Older adults, because your skin doesn't make vitamin D when exposed to sunlight as efficiently as when you were young, and your kidneys are less able to convert vitamin D to its active form.
• People with dark skin, which has less ability to produce vitamin D from the sun.
• People with conditions that make it difficult to absorb nutrients from food, such as Crohn's disease, ulcerative colitis, and celiac disease.
• People who have obesity, because their body fat binds to some vitamin D and prevents it from getting into the blood.
• People who have had gastric bypass surgery, a type of weight loss surgery which creates a bypass of part of the small intestine. Since vitamin D is absorbed there, bypassing part of it makes it harder to absorb enough vitamin D.
• People with chronic kidney or liver disease, which can affect your ability to change vitamin D into a form your body can use.
• People who take medicines that affect vitamin D levels, including certain cholesterol, anti-seizure, steroid, and weight-loss medicines.

Talk with your provider if you are at risk for vitamin D deficiency. There is a blood test that can measure how much vitamin D is in your body.

Vitamin D deficiency can lead to a loss of bone density, which can contribute to osteoporosis and fractures (broken bones).

Severe vitamin D deficiency can also lead to other diseases:

• In children, it can cause rickets. Rickets is a rare disease that causes the bones to become soft and bend. African American infants and children are at higher risk of getting rickets.
• In adults, severe vitamin D deficiency leads to osteomalacia. Osteomalacia causes weak bones, bone pain, and muscle weakness.

There are a few foods that naturally have some vitamin D:

• Fatty fish such as salmon, tuna, and mackerel
• Beef liver
• Cheese
• Mushrooms
• Egg yolks

You can also get vitamin D from fortified foods. You can check the food labels to find out whether a food has vitamin D. Foods that often have added vitamin D include:

• Milk
• Breakfast cereals
• Orange juice
• Other dairy products, such as yogurt
• Soy drinks

Vitamin D is in many multivitamins. There are also vitamin D supplements, both in pills and in a liquid for babies.

If you have vitamin D deficiency, the treatment is with supplements. Check with your provider about how much you need to take, how often you need to take it, and how long you need to take it.

Getting too much vitamin D (known as vitamin D toxicity) can be harmful. Signs of toxicity include nausea and vomiting, poor appetite, constipation, weakness, and weight loss.

Very high levels of vitamin D can damage the kidneys. It also raises the level of calcium in your blood. High levels of blood calcium (hypercalcemia) can cause confusion, kidney failure, and irregular heartbeat (arrhythmia).

Most cases of vitamin D toxicity happen when someone overuses vitamin D supplements. You cannot get too much vitamin D from sun exposure because the skin limits the amount of vitamin D it makes.

Your bones help you move, give you shape and support your body. They are living tissues that rebuild constantly throughout your life. During childhood and your teens, your body adds new bone faster than it removes old bone. After about age 20, you can lose bone faster than you make bone. To have strong bones when you are young, and to prevent bone loss when you are older, you need to get enough calcium, vitamin D, and exercise. You should also avoid smoking and drinking too much alcohol.

Bone diseases can make bones easy to break. Different kinds of bone problems include:

• Low bone density and osteoporosis, which make your bones weak and more likely to break
• Osteogenesis imperfecta makes your bones brittle
• Paget's disease of bone makes them weak
• Bones can also develop cancer and infections
• Other bone diseases, which are caused by poor nutrition, genetics, or problems with the rate of bone growth or rebuilding

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Calcium is a mineral, a nutrient that you need (in small amounts) to keep your body healthy. You have more calcium in your body than any other mineral.

Calcium has many important jobs:

• To build and maintain strong bones. Your body stores almost all of its calcium in your bones and teeth to keep them strong.
• To help your muscles move.
• To help your nerves to carry messages between your brain and the rest of your body.
• To help your blood vessels move blood throughout your body.
• To help release hormones that affect many functions in your body.

Not getting enough calcium can cause several conditions, including:

• Osteoporosis, a disease which can make your bones weaker and more likely to break.
• Rickets, a disease in children that causes soft, weak bones.
• Osteomalacia, a condition which causes soft bones in children and adults.

You can get calcium from foods and supplements. You may be able to get enough calcium by eating a variety of foods, including:

• Dairy products such as milk, cheese, and yogurt. These are the main food sources of calcium for most people in the United States.
• Leafy, green vegetables such as kale, broccoli, and Chinese cabbage (bok choi).
• Fish with soft bones that you can eat, such as canned sardines and salmon.
• Calcium-enriched foods such as breakfast cereals, fruit juices, soy and rice drinks, and tofu. The product labels for these foods will show how much calcium they have.

Calcium is available in supplements. It is also included in many multivitamins. The two main forms of calcium supplements are calcium carbonate and calcium citrate:

• Calcium carbonate is absorbed best when taken with food. Some over-the-counter antacids, such as Tums and Rolaids, also contain calcium carbonate.
• Calcium citrate is absorbed well on an empty stomach or a full stomach. People with low levels of stomach acid absorb calcium citrate more easily than calcium carbonate.

Calcium is absorbed best when you take 500 mg or less at one time. If you are taking more than that amount each day, take a smaller dose twice a day rather than taking it all at once.

Calcium supplements might cause gas, bloating, and constipation in some people. If you have any of these symptoms, you could try:

• Spreading out the calcium dose throughout the day
• Taking it with meals
• Switching the form of calcium you take

The amount of calcium you need each day depends on your age and other factors. The recommended amounts, in milligrams (mg), are:

• Birth to 6 months: 200 mg
• Infants 7-12 months: 260 mg
• Children 1-3 years: 700 mg
• Children 4-8 years: 1,000 mg
• Children 9-13 years: 1,300 mg
• Teens 14-18 years: 1,300 mg
• Adults 19-50 years: 1,000 mg
• Adult men 51-70 years: 1,000 mg
• Adult women 51-70 years: 1,200 mg
• Adults 71 years and older: 1,200 mg
• Pregnant and breastfeeding teens: 1,300 mg
• Pregnant and breastfeeding adults: 1,000 mg

Certain people may have trouble getting enough calcium, including:

• Children and teens age 4 to 18 years
• People who are Black or Asian
• Adults age 50 years and older living in poverty
• Postmenopausal women; your body absorbs and retains less calcium after menopause
• People who don't drink milk or eat other dairy products

Check with your health care provider to see if you need to take calcium supplements, and if so, how much you should take. Your provider may want to first do a calcium blood test to see if you are getting enough of it.

NIH: National Institutes of Health Office of Dietary Supplements