More and more, people are waking up to the fact that vitamin D deficiency is a global health problem and ignored epidemic. According to a 2010 study published in the International Journal of Health Sciences, over 1 billion people worldwide are affected by vitamin D deficiency.
Even in the developed world, vitamin D deficiency is a huge problem. According to another 2009 study published in the Journal of the American Medical Association, nearly 3 out of 4 US teens and adults are vitamin D deficient and the rates of vitamin D deficiency have skyrocketed in the past 30 years.
Vitamin D is an essential nutrient that your body cannot live without. Normally, vitamin D is produced by a reaction between your skin and sunlight, which is why vitamin D deficiency seems to be more common in those who live in areas that receive relatively little sunlight and those who spend the majority of their time indoors. Symptoms of vitamin D deficiency include:
Vitamin D deficiency has also been linked to increased risk of some types of cancer, cardiovascular disease, and metabolic disorders like diabetes.
In this article, we are going to talk about the global epidemic that is vitamin D deficiency, how vitamin D works in the body, what the symptoms of vitamin D are, and how you can prevent vitamin D deficiency.
Vitamin D is a fat-soluble steroid that is an essential nutrient for human health. There are several different types of vitamin D, the most important for humans being vitamin D3 (also called cholecalciferol) and vitamin D2 (ergocalciferol). Vitamin D was first discovered in the early 20th century by American physicians Elmer McCollum and Marguerite Davis, who identified vitamin D deficiency as the main cause of rickets—a nutritional disorder in children characterized by bowed legs, stunted growth, and periodic muscle spasms.
The main natural source of vitamin D is the sun. Vitamin D is produced in the upper layer of the epidermis via a chemical reaction that is dependent on UV radiation from the sun. This is why vitamin D is often called the “sunshine” vitamin. The body does not produce vitamin D other than via UV radiation, and very few foods contain significant amounts of vitamin D. Several oral supplements of vitamin D exist.
Technically, vitamin D is not an essential vitamin as it can be synthesized by the body. However, the lack of other adequate natural sources of vitamin D aside from sunlight often make medical professionals classify it as an essential vitamin. There is also some evidence that people with dark skin are more likely to develop a vitamin D deficiency as the increased amount of melanin in the skin its more difficult for the necessary chemical reaction to occur.
When first synthesized, vitamin D cannot actually do anything. It must first be activated by other enzymes before it can interact with the body and perform its functions.
Vitamin D is one of the most important nutrients for the body and is responsible for a number of functions. Perhaps most importantly, vitamin D helps your body absorb calcium, magnesium, and phosphates, three extremely important elements that are needed for bone growth/maintenance and regulating muscle and nerve function. Vitamin D also affects the activation of T and B cells in the immune system, and affects the synthesis of growth hormones.
According to most medical professionals, normal vitamin D blood levels should be in the range of 20-50ng/mL. A person is in a state of vitamin D deficiency when blood levels drop below 12ng/mL.
The majority of serious symptoms of vitamin D deficiency affect the bones, immune system and muscles.
The most serious symptom of vitamin D deficiency is reduced bone mass and bone pains. Your skeleton relies on calcium and magnesium to repair and maintain itself. If there is not enough vitamin D in your body, it cannot do this so your bones lose mass and can become brittle. Vitamin D deficiency in young children is the main cause of rickets, a disease that results in weak and soft bones. Rickets is a very rare condition in the West but still relatively common in underdeveloped regions of Africa, Asia, and the Middle East. Vitamin D deficiency is also linked to a greater risk of osteoporosis in the elderly.
A large observational study of more than 1,100 middle-aged women found a very strong link between vitamin D deficiency and below-average bone mineral density. Many people with bone disorders believe it comes from a lack of calcium. While this is true, without vitamin D, your body cannot absorb calcium so vitamin D is also necessary for bone health. Another study published in the New England Journal of Medicine found that vitamin D supplementation greatly reduced bone mass loss in men and women older than 65.
Vitamin D also seems to play a role in regulating nerve and muscle function. Vitamin D affects the ion channels in muscle and nerve cells that create the electric potential needed for nerve communication and muscle contraction. This function could explain why vitamin D deficiencies are associated with weakness/fatigue, poor muscle control, and cognitive impairment in the elderly.
Vitamin D also seems to play a role in wound healing. Studies suggest that vitamin D stimulates the production of compounds that are needed for forming new skin during the wound healing process. There is also some evidence that vitamin D plays a role in controlling inflammation and fighting infection, two important healing factors. It has also been shown that those with severe vitamin D deficiencies tend to have much higher levels of inflammatory markers which can impede the healing process.
There is some evidence that suggests vitamin D may be involved in the onset of depressive episodes. Researchers have linked vitamin D deficiency to depression in older adults, although some large observational studies have not shown a substantial link. If vitamin D deficiency is related to depression, it is likely through indirect means. Lack of adequate sunlight is one of the major causes of vitamin D deficiency, and it is also a major factor in seasonal depression disorders. So it could be that the two conditions share a common cause.
One of the more important functions of vitamin D is keeping your immune system strong so you can fight off bacteria and viruses.Vitamin D directly interacts with the cells that help fight infections, which explains why vitamin D deficiency is linked to a weak immune system. Several observational studies have also found a link between vitamin D deficiency and an increased risk of respiratory tract infections, like bronchitis, pneumonia, and the common cold.
Stress is one of the major causes of hair loss, though it can also be caused by various nutritional deficiencies. There is some evidence linking vitamin D deficiency to hair loss. One study found that alopecia areata, an autoimmune disorder that causes severe hair loss, is associated with rickets, which is caused by a vitamin D deficiency. Other studies have linked low vitamin D levels directly to hair loss.
Other studies have shown that topical application of vitamin D can stimulate hair growth in patients with hair loss disorders.
Vitamin D deficiency is also characterized by non-specific pain in the muscles and bones. The exact causes of muscle pain are difficult to figure out, but there is some evidence that vitamin D affects pain conduction and vitamin D deficiencies are linked to non-specific muscle pains. Vitamin D has been shown to be active in the nerve cells that conduct pain signals (called nociceptors) and a handful of studies on lab rats have shown that vitamin D deficiency was linked with overactivation of nociceptors. Other studies have shown that taking vitamin D supplements can reduce nociceptive and neuropathic pain in patients that are deficient.
Since exposure to the sun is the only natural way for the body to produce vitamin D most medical experts recommend taking vitamin D dietary supplements. The majority of these supplements are in pill form and can be consumed with meals. You can also buy liquid vitamin D supplements that can be directly ingested with an eyedropper. There also exist vitamin D supplements in powder form, although these tend to be a bit more expensive and normally have other supplements for athletes and weightlifters.
Another reason you should take vitamin D supplements is that exposure to sunlight, the main mechanism for synthesizing vitamin D in the body, is linked to higher rates of skin cancers.
Doctors at the Mayo Clinic recommend to ingest at least 400-800 IU of vitamin D a day, which is about 10-20 micrograms. However, some professionals recommend a higher 500-1000 IU (50-100 micrograms) daily dosage. The amount of vitamin D you should take depends heavily on what your resting levels are. If you are very deficient, you should take more.
Can I take too much vitamin D? Probably not. Vitamin D toxicity is very rare and is almost always caused by taking significantly more than the recommended daily dose. As of now, we do not know the exact toxic level of vitamin D, but some researchers put the number at over 200 micrograms a day. Some studies have indicated that sustained consumption of more than 125 micrograms of vitamin D a day can cause toxicity in adults.
What are some side effects of taking Vitamin D? The most common side effect of taking vitamin D is hypercalcemia (elevated levels of blood calcium). When calcium levels are high, the body begins depositing calcium on soft tissues and organs. Hypercalcemia results in excess thirst, frequent urination, lack of appetite, nausea, vomiting, weakness, and in very extreme cases, kidney damage. Those with hormone disorders like hyperthyroidism are more likely to experience these side effects.
Most of the time, these symptoms go away when you quit taking vitamin D supplements. If kidney damage is severe, it can be irreversible. If you want to start taking vitamin D supplements, make sure to talk to your doctor first. You should also get regular blood work done to make sure that everything is within healthy parameters.
Vitamin D toxicity seems to be most serious in young children where it can cause mental retardation, abnormal bone growth, diarrhea, excessive weight loss, and acute irritability. It can also be acute in the elderly.
Should I get vitamin D supplements in pill or liquid form? It depends on your personal preferences. There is some evidence that liquid-based vitamin D supplements are easier for your body to metabolize and absorb, though liquid supplements are sometimes more expensive than their pill counterparts.
Can I get enough Vitamin D from sunlight? Theoretically, yes. You can get all the vitamin D you need from sunlight. However, doctors recommend taking supplements because excessive UV exposure can increase the risk of developing skin cancers.
What foods contain vitamin D? Unfortunately, there are not many foods that contain substantial amounts of vitamin D. Fatty fish like tuna, mackerel, and salmon contain higher than average levels of vitamin D, but not in sufficient quantities for that to be your sole source. Many processed foods you can buy at the grocery store contain vitamin D additives, and dairy products tend to be a decent source of vitamin D (and calcium!).
Vitamin D deficiency is a growing global health concern but you do not have to be another medical statistic. As long as you get adequate sunlight and supplement your routine with vitamin D, you should be fine. If you do notice any symptoms of vitamin D deficiency, talk to your primary care physician about taking vitamin D supplements.