What is Vitamin D Deficiency?
Vitamin D, a type of vitamin that dissolves in fat, is crucial for maintaining a balance of calcium in the body and for the health of our bones. A lack of Vitamin D can cause diseases such as osteomalacia and rickets in children and osteomalacia in adults. Adding vitamin D to milk in the 1930s effectively got rid of rickets globally.
But even today, a mild deficiency of vitamin D, is quite common across both developing and developed countries, with up to 1 billion people worldwide affected. This mild deficiency can increase the risk of bone thinning (osteoporosis), falls, and fragile bones that break easily.
There are also many recent studies with varied results, showing a potential link between a lack of vitamin D and health conditions like cancer, heart diseases, diabetes, diseases where the immune system attacks the body (autoimmune diseases), and depression.
What Causes Vitamin D Deficiency?
We get most of our vitamin D from two avenues – our skin making it when we’re in the sun (dermal synthesis) and from eating certain foods (dietary intake) like fatty fish livers or foods fortified with the vitamin. These two types of vitamin D, D2 and D3, are changed in the liver to versions known as 25-OH-D2 and 25-OH-D3, respectively. Then these are altered again in the kidneys to become the most active form of vitamin D (1,25 dihydroxyvitamin D). This form of vitamin D helps our bodies absorb calcium from the intestines, break down bone, and cut back on the calcium and phosphate our kidneys release.
However, several issues could lead to low levels of vitamin D, including:
1. Not getting enough vitamin D through diet or struggling to absorb it
Certain diseases that disrupt how we absorb food and nutrients – such as celiac disease, short bowel syndrome, gastric bypass surgery, inflammatory bowel disease, chronic pancreatic insufficiency, and cystic fibrosis – could result in not getting enough vitamin D. Also, older people tend to consume less vitamin D.
2. Not getting enough sun
Regular sun exposure helps prevent vitamin D deficiency. You need about 20 minutes of sun each day, with over 40% of your skin exposed to maintain healthy levels. However, as we age, our skin isn’t as good at making vitamin D. People with darker skin tones and those who don’t get outside much (such as people in hospitals or institutions) might not get enough sun for adequate vitamin D synthesis. Regular use of sunscreens can also decrease effective sun exposure, affecting vitamin D levels.
3. Not being able to create vitamin D internally
Those living with chronic liver disease, such as cirrhosis, might struggle to make enough active vitamin D due to defective 25-hydroxylation. Issues with the kidney and certain other conditions could interfere with the creation of active vitamin D as well.
4. Quick breaking down of vitamin D
Certain medications – like phenobarbital, carbamazepine, dexamethasone, nifedipine, spironolactone, clotrimazole, and rifampin – can trigger enzymes in the liver that break down vitamin D faster, leading to lower levels.
5. Body can’t use vitamin D
Some people have a condition called hereditary vitamin D-resistant rickets that makes their bodies unable to use vitamin D correctly, leading to deficiency.
Risk Factors and Frequency for Vitamin D Deficiency
Vitamin D deficiency is a major global health concern, with approximately 1 billion people around the world lacking enough of this essential nutrient. Half the world’s population doesn’t get enough vitamin D. The elderly, obese individuals, people living in nursing homes, and hospitalized patients are the groups most likely to be deficient in vitamin D, irrespective of where they live or their age. For instance, obesity increases the chance of having a vitamin D deficiency by 35%.
- In the United States, 50-60% of nursing home residents and hospital patients are vitamin D deficient.
- People with higher skin melanin content and those who cover their skin extensively, often seen in Middle Eastern countries, are also at higher risk for vitamin D deficiency.
- About 47% of African American infants and 56% of Caucasian infants in the United States are vitamin D deficient. This issue is even more widespread in countries like Iran, Turkey, and India, where over 90% of infants lack adequate vitamin D.
- As for adults, 35% in the United States are deficient in vitamin D, while over 80% of adults in Pakistan, India, and Bangladesh have the same issue.
- A significant majority of the elderly population is vitamin D deficient: 61% in the United States, 90% in Turkey, 96% in India, 72% in Pakistan, and 67% in Iran.
Signs and Symptoms of Vitamin D Deficiency
Vitamin D deficiency often doesn’t show any symptoms in many people. However, a mild, long-term lack of vitamin D can result in chronic low calcium levels and overactive parathyroid glands. These conditions can increase the risk of weak bones (osteoporosis), falls, and bone fractures, particularly in older people. If the deficiency of vitamin D is severe and long-standing, it can lead to additional symptoms which are associated with an overactive parathyroid gland. Such symptoms include bone pain, joint pain, muscle pain, tiredness, muscle twitches, and weakness. Chronic vitamin D deficiency can even lead to fragile bones that break easily, a condition known as osteoporosis. In children, lack of vitamin D may lead to symptoms like crankiness, fatigue, developmental delays, changes in bone structure or fractures.
- Chronic low calcium levels
- Overactive parathyroid glands
- Risk of weak bones (osteoporosis), falls, and bone fractures
- Bone pain
- Joint pain
- Muscle pain
- Tiredness
- Muscle twitches
- Weakness
- Fragile bones that break easily (osteoporosis)
- In children: crankiness, fatigue, developmental delays, changes in bone structure or fractures
Testing for Vitamin D Deficiency
People who are at high risk should have their vitamin D levels checked. Doctors can tell if a person has enough vitamin D or if they are deficient through a test that measures the amount of a particular form of Vitamin D in the blood, known as 25-hydroxyvitamin D. However, the exact amount of this type of Vitamin D that should be in the blood to be considered healthy is still a matter of debate.
It’s important to consider that the way our bodies handle minerals can vary significantly between different racial groups. For instance, African Americans tend to have denser bones and are less likely to suffer from fractures compared to other racial groups. The impact of taking calcium and vitamin D supplements is not yet fully understood or reported for people who are not White.
The International Society for Clinical Densitometry and the International Osteoporosis Foundation suggest that in order to reduce the risk of falls and fractures in older individuals, the amount of 25-hydroxyvitamin D in the blood should be at least 30 ng/mL. However, there isn’t enough information available about the maximum safe level of 25-hydroxyvitamin D in the blood. It’s important to note that very high levels, such as above 100 ng/mL, could potentially lead to a condition known as secondary hypercalcemia, which means there is too much calcium in the blood.
Additionally, when a person is found to have a vitamin D deficiency, doctors should also check for a condition known as secondary hyperparathyroidism. In such a scenario, the levels of parathyroid hormone and calcium in the blood should be checked.
Treatment Options for Vitamin D Deficiency
There are several types of vitamin D. However, research shows that Vitamin D3, also known as cholecalciferol, is more efficient in reaching the desired levels of vitamin D than Vitamin D2 or ergocalciferol. Therefore, Vitamin D3 is often the preferred choice for treating deficiencies.
To prevent a vitamin D deficiency, adults under 65 who don’t get enough sun year-round should take between 600 and 800 international units of Vitamin D3 per day. For older adults aged 65 and over, the recommended daily dosage increases to between 800 and 1000 international units of Vitamin D3. This not only helps prevent a deficiency but can also reduce the risk of fractures and falls.
Treating a vitamin D deficiency depends heavily on how deficient you are and whether you have any underlying risk factors. For most people, an initial course of either 6,000 international units of Vitamin D3 daily or 50,000 international units weekly for about 8 weeks can help restore vitamin D levels. After that, a daily dose of 1,000 to 2,000 international units is recommended to maintain the right vitamin D level.
However, high-risk individuals with a vitamin D deficiency like African Americans, Hispanics, the obese, those on certain medications, or those with malabsorption syndrome may need a higher initial daily dose of 10,000 international units of Vitamin D3. Once their vitamin D levels go above 30 ng/mL, a regular daily dose of 3,000 to 6,000 international units is usually advised.
Children who are vitamin D deficient require 2000 international units per day of Vitamin D3 or a weekly dose of 50,000 international units for 6 weeks to restore their levels. After reaching the right level (above 30 ng/mL), 1000 international units of Vitamin D3 per day is recommended. The American Academy of Pediatrics suggests that breastfed infants and children not drinking at least 1-liter of vitamin D-fortified milk daily should take a supplement of 400 international units of vitamin D.
If the deficiency persists despite taking Vitamin D2 or D3, other medications like Calcitriol or Calcidiol can be considered. These options, however, need careful monitoring of blood calcium levels due to an increased risk for hypercalcemia. Calcidiol is especially a good option for individuals with severe liver diseases or problems absorbing fats.
What else can Vitamin D Deficiency be?
When assessing certain health conditions, doctors need to consider a variety of factors that could potentially explain the patient’s symptoms. Here are some instances where this might be necessary:
- Celiac disease
- Cystic fibrosis
- Late-stage liver disease
- Not getting enough sunlight
- Not eating a balanced diet
- Taking certain medications like those for epilepsy
It’s crucial for the healthcare provider to carefully evaluate these possibilities through appropriate tests to ensure the accuracy of their diagnosis.
