What is vitamin D deficiency?

 What is vitamin D deficiency?

Vitamin D deficiency means you don’t have enough vitamin D in your body. It primarily causes issues with your bones and muscles.

Vitamin D is an essential vitamin that your body uses for normal bone development and maintenance. Vitamin D also plays a role in your nervous system, musculoskeletal system and immune system.  You can get vitamin D in a variety of ways, including:

• Sun exposure on your skin (however, people with darker skin and older people may not get enough vitamin D through sunlight. Your geographical location may also prevent adequate vitamin D exposure through sunlight).
• Through the food you eat.
• Through nutritional supplements.

Despite all these methods to get vitamin D, vitamin D deficiency is a common worldwide problem.

Why is vitamin D so important?

Vitamin D is one of many vitamins your body needs to stay healthy. It plays a crucial role in maintaining the balance of calcium in your blood and bones and in building and maintaining bones.

More specifically, you need vitamin D so your body can use calcium and phosphorus to build bones and support healthy tissues.

With chronic and/or severe vitamin D deficiency, a decline in calcium and phosphorus absorption by your intestines leads to hypocalcemia (low calcium levels in your blood). This leads to secondary hyperparathyroidism   (overactive parathyroid glands attempting to keep blood calcium levels normal).

Both hypocalcemia and hyperparathyroidism, if severe, can cause symptoms, including muscle weakness and cramps, fatigue and depression.

To try to balance calcium levels in your blood (via secondary hyperparathyroidism), your body takes calcium from your bones, which leads to accelerated bone demineralization (when a bone breaks down faster than it can reform).

This can further result in osteomalacia (soft bones) in adults and rickets in children.

Osteomalacia and osteoporosis put you at an increased risk for bone fractures.  Rickets is the same as osteomalacia, but it only affects children. Since a child’s bones are still growing, demineralization causes bowed or bent bones.

Causes of Vitamin D Deficiency

Vitamin D deficiency can occur for a number of reasons:

You don't consume the recommended levels of the vitamin over time. This is likely if you follow a strict vegan diet, because most of the natural sources are animal-based, including fish and fish oils, egg yolks, fortified milk, and beef liver. Here are the best vitamin d foods for vegetarians.

Your exposure to sunlight is limited. Because the body makes vitamin D when your skin is exposed to sunlight, you may be at risk of deficiency if you are homebound, live in northern latitudes, wear long robes or head coverings for religious reasons, or have an occupation that prevents sun exposure. During the winter, vitamin D deficiency can be more prevalent because there is less sunlight available.

You have dark skin. The pigment melanin reduces the skin's ability to make vitamin D in response to sunlight exposure. Some studies show that older adults with darker skin are at high risk of vitamin D deficiency.

Your kidneys cannot convert vitamin D to its active form. As people age, their kidneys are less able to convert vitamin D to its active form, thus increasing their risk of vitamin D deficiency.

Your digestive tract cannot adequately absorb vitamin D. certain medical problems, including crohn’s disease,   cystic fibrosis, and celiac disease can affect your intestine's ability to absorb vitamin D from the food you eat.

You are obese. Vitamin D is extracted from the blood by fat cells, altering its release into circulation. People with a body mass index of 30 or greater often have low blood levels of vitamin D.

Symptoms of Vitamin D Deficiency, 

The majority of people with a vitamin D deficiency do not present with symptoms. However, a chronic deficiency may cause hypocalcemia, a calcium deficiency disease, and hyperparathyroidism, where the parathyroid glands create a hormone imbalance that raises the blood calcium levels.

These conditions can lead to secondary symptoms including:

• bone fragility, especially in older adults
• osteoporosis
• bone pain
• fatigue
• muscle twitching
• muscle weakness
• myalgias, or muscle pain
• arthralgias, or joint stiffness

If Vitamin D deficiency continues for long periods, it may result in complications, such as:

• cardiovascular conditions
• autoimmune problems
• neurological diseases
• infections
• pregnancy complications
• Certain cancers.  including breast, prostate, and colon

 

Diagnosis Vitamin D Deficiency

In order to absorb vitamin D, your liver converts it into 25 hydroxyvitamin D, or 25(OH) D. Your kidneys use 25(OH) D to make “active vitamin D,” which helps your body utilize calcium for your bone and cell health. A blood test can be used to check the level of 25(OH) D in your blood, which is regarded as the most accurate way to determine if you are vitamin D deficient. Results are determined by the following readings:

• Not vitamin D deficient: 25 (OH)D level of 21-50 nanograms per milliliter (ng/mL)
• Vitamin D deficient: 20 ng/mL or lower
• Severely vitamin D deficient: 12 ng/mL or lower

There are other indirect signs that you may have vitamin D deficiency. For instance, if there are low levels of calcium in your urine, this could be an indication of low vitamin D levels. Similarly, bone mineral density and bone breaks (fractures) appearing on X-rays may also be a sign to check your vitamin D levels.

 

The most accurate way to measure how much vitamin D is in your body is the 25-hydroxy vitamin D blood test. A level of 20 nanograms/milliliter to 50 ng/mL is considered adequate for healthy people. A level less than 12 ng/mL indicates vitamin D deficiency.

Treatment for Vitamin D Deficiency

Treatment for vitamin D deficiency involves getting more vitamin D -- through diet and supplements. Although there is no consensus on vitamin D levels required for optimal health -- and it likely differs depending on age and health conditions -- a concentration of less than 20 nanograms per milliliter is generally considered inadequate, requiring treatment.

Guidelines from the Institute of Medicine increased the recommended dietary allowance (RDA) of vitamin D to 600 international units (IU) for everyone ages 1-70, and raised it to 800 IU for adults older than age 70 to optimize bone health. The safe upper limit was also raised to 4,000 IU. Doctors may prescribe more than 4,000 IU to correct a vitamin D deficiency.

If you don't spend much time in the sun or always are careful to cover your skin (sunscreen inhibits vitamin D production), you should speak to your doctor about taking a vitamin D supplement, particularly if you have risk factors for vitamin D deficiency.