What Is Vitamin D Deficiency?
Vitamin D is a fat-soluble vitamin that helps the body absorb dietary calcium and phosphorus from the intestines and suppresses the release of parathyroid hormone, a hormone that causes bone resorption. This serves to keep the bones healthy. Vitamin D is also believed to improve muscle and immune function.
Vitamin D is made in the skin when it is exposed to sunlight. Vitamin D is also naturally occurring in certain foods such as fatty fish, cod liver oil, and eggs. It is also found on fortified foods such as cow’s milk.
Low levels of vitamin D are referred to as vitamin D deficiency.
What Are Symptoms of Vitamin D Deficiency?
Symptoms of vitamin D deficiency include:
What Causes Vitamin D Deficiency?
Vitamin D deficiency may be caused by:
- Low levels of vitamin D in the diet along with inadequate sun exposure
- Human breast milk contains low levels of vitamin D, and most infant formulas do not contain adequate vitamin D
- Older adults often do not eat enough vitamin D-rich foods, and when they do, absorption may be limited
- Exposure to the sun is not recommended as a source of vitamin D for infants and children because of the potential risks of skin cancer
- Certain conditions that result in an inability to absorb vitamin D from the intestines
- Celiac disease
- Crohn's disease
- Cystic fibrosis
- Surgery that removes or bypasses portions of the stomach or intestines such as gastric bypass
- An inability to process vitamin D due to kidney or liver disease
- Certain medications
How Is Vitamin D Deficiency Diagnosed?
Vitamin D deficiency is diagnosed with a blood test called 25-hydroxyvitamin D or 25(OH)D (OH = hydroxy, D = vitamin D).
What Is the Treatment for Vitamin D Deficiency?
Treatment for vitamin D deficiency includes:
- Vitamin D supplements
- The recommended dose of vitamin D depends upon the nature and severity of the vitamin D deficiency
- Additional supplements
- Calcium - 1000 mg of calcium per day for premenopausal women and men and 1200 mg per day for postmenopausal women
Foods that are good sources of vitamin D include:
- Meat and poultry
- Beef liver
- Chicken breast
- Ground beef
- Mushrooms – white and portabella
- Dairy products
- Milk, vitamin D fortified
- Cheddar cheese
- Cod liver oil
- Plant-based milks (e.g. soy, almond, oat), vitamin D fortified
- Ready-to-eat cereals, vitamin D fortified
Exposure to sunlight is also another source for vitamin D but too much sun exposure can lead to sunburns, premature skin aging, eye damage, heat exhaustion or heat stroke, or skin cancer. Talk to your doctor about how much sun exposure you may need and how to get exposure safely.
What Are Complications of Vitamin D Deficiency?
Complications of vitamin D deficiency include:
- Low blood calcium (hypocalcemia)
- Low blood phosphate (hypophosphatemia)
- Rickets (softening of the bones during childhood)
- Osteomalacia (softening of the bones in adults)
- Decreased bone density (osteopenia or osteoporosis)
- Elevated parathyroid hormone (which accelerates bone resorption)
- Increased risk of falls that may result in fractures
How Do You Prevent Vitamin D Deficiency?
Prevention of vitamin D deficiency depends upon a person’s skin color, sun exposure (which can be affected by the season and where a person lives), diet, and underlying medical conditions.
- Adults may be advised to take a supplement of 800 IU (20 micrograms) of vitamin D daily. Older people confined indoors may need higher doses.
- Infants and children may be advised to take a vitamin D supplement containing 400 IU (10 micrograms) of vitamin D, which included in most nonprescription infant multivitamin drops.
- Exposure to sunlight is also another source for vitamin D. Talk to your doctor about how much sun exposure you may need and how to get exposure safely.