Are you getting enough vitamin D? You might think so, but unless you consistently eat a balanced diet, get sunlight exposure, and take supplemental nutrients, you may not get enough vitamin D. You may even have a vitamin D deficiency. In fact, the Centers for Disease Control and Prevention (CDC) estimates that approximately 30 to 40 percent of the United States population doesn't get enough of this critical micronutrient. This is of importance to all of us as vitamin D has a significant impact on your overall health and well-being.
What Is Vitamin D?
Vitamin D is an important, fat-soluble vitamin that's crucial for good health. There are two types of vitamin D: vitamin D2, or ergocalciferol, and vitamin D3, or cholecalciferol. Vitamin D2 is found in some supplements and fortified foods. Vitamin D3 is what the body produces from exposure to the sun's ultraviolet rays, and, compared to D2, vitamin D3 is more readily absorbed and used by the body. That's one of the features that distinguishes vitamin D from other micronutrients like vitamins A, B, and C – the human body creates it after direct exposure to sunlight, which is why it is often referred to as the "sunshine vitamin."
The Role of Vitamin D in Your Body
The brain, bones, immune system, and virtually every other cell in the body have specific receptors for vitamin D and require it in order to function at peak efficiency. Vitamin D supports bone health and helps prevent childhood diseases like bone-softening rickets and old-age diseases like osteoporosis and osteomalacia. But vitamin D's importance goes beyond our bones. In 1903, Danish physician Niels Finsen was awarded the Nobel Prize for his pioneering treatment of tuberculosis with ultraviolet light. And while it was unknown at the time why Finsen's "heliotherapy" worked so well, scientists now understand that vitamin D and calcitriol played an important role in its success.
In a 2011 study, Oxford University researchers discovered that vitamin D directly influences over 200 genes, including many that have are implicated in autoimmune disorders, cardiovascular disease, and even cancer. Other studies are now showing the role of the micronutrient in promoting bone health, heart health, and the immune system. This is why having adequate levels of D3 circulating in your blood is so important for optimal health. According to the Vitamin D Council, adequate levels are in the range of 40-80 ng/mL.
How Much Vitamin D Does Your Body Need?
The recommended daily allowance for vitamin D is the minimum daily intake necessary to support bone health. Some scenarios, like pregnancy or health certain conditions, may require more. The recommendations are provided in international units (IUs). For reference, one microgram is equivalent to 40 IU.
|0 – 12 months||400 IU|
|1 – 70 years||600 IU|
|70+ years||800 IU|
|Pregnant women||600 IU|
|Breastfeeding women||600 IU|
Symptoms of Vitamin D Deficiency
- Muscle weakness
- Bone aches
If you don't get enough vitamin D on a regular basis, you could experience vitamin D deficiency. The symptoms of vitamin D deficiency are subtle. While some people may experience muscle weakness, fatigue, bone aches, or just general feelings of malaise, the vast majority of people likely won't be able to gauge their vitamin D levels without a blood test – especially in the early days of a deficiency. Many symptoms, like high blood pressure, increased risk of infections, and bladder issues, are chalked up to other health concerns.
Most people won't have any symptoms of vitamin D deficiency.
Chronic vitamin D deficiency will affect nearly every aspect of your well-being. Some of the more serious diseases linked to consistently low vitamin D levels include cardiovascular disease, osteoporosis, autoimmune disorders, diabetes, and a host of neurological conditions. New research also shows that adequate vitamin D levels are crucial to a healthy pregnancy and it helps the developing baby avoid health issues later on in life, too.
If you suspect you may be vitamin D deficient, get tested. Vitamin D levels can be evaluated with a blood test. Normal blood levels are within the 40-80 ng/mL range. Be sure to ask your doctor for the 25-hydroxy vitamin D blood test during your annual physical to ensure your readings are accurate. A result of 20 ng/mL or less could result in increased risk for mood disorders, cognitive impairment, and periodontal disease, among others.
Causes of Vitamin D Deficiency & Who Is At Risk
Vitamin D deficiency, or even low vitamin D levels, can occur for a variety of reasons. Many people don't get enough sun exposure. Some people don't get enough vitamin D in their diet, which can be tricky, as there aren’t many foods that are a good natural source of vitamin D. Certain health conditions, such as being overweight, can affect vitamin D levels, as can being older, breastfeeding, and other situations.
Little or No Sun Exposure
People who don't get enough exposure to sunlight, whether it be by staying indoors, living in an area with inconsistent sunlight, or only venturing outside with sunscreen, are at risk for low vitamin d levels, and even vitamin d deficiency. Clouds, shade, windows, and sunscreen all block the UV rays that prompt your body to begin vitamin D production. All year long, you should try to find time to get a little sunlight on your skin.
Certain Dietary Restrictions
There aren't many foods that are natural sources of vitamin D, so it's easy to fall short of your vitamin d requirements because of your diet. Some foods are fortified with vitamin D but it's usually in the form of vitamin D2. Vegans, vegetarians, and anyone who doesn't consume fish, dairy, or the other animal foods that do provide a measure of vitamin D may also find themselves lacking in the vitamin D department.
Obesity is a big risk factor for vitamin D deficiency. The body draws calcitriol from the body's fat cells. If you are overweight, it is more difficult for your fat cells to release sufficient levels of this micronutrient to circulate in the blood.
The nutrient content of breast milk is related to the mother’s nutritional status. If she’s low on vitamin D (or any other nutrient, for that matter) her breast milk will be too. When you consider that infants don’t, and shouldn’t, spend much time in direct sunlight, it’s no wonder that they may be at risk for vitamin D deficiency. Vitamin D supplementation is often recommended during infancy, but check with your healthcare provider to ensure the right serving and protocol.
The process of getting older can present many challenges and having low vitamin D levels is one of them. As people age, it’s harder for their skin to produce vitamin D as efficiently as it used to. When you combine that with the fact that many older adults spend more time indoors, it’s easy to understand why they need to be especially vigilant about maintaining adequate vitamin D levels (and their overall nutrient levels in general).
People With More Melanin
People with a darker skin tone may have difficulty reaching peak vitamin D levels as a result of higher levels of the pigment melanin. With darker skin tone, more exposure to sunlight is necessary for the body to make adequate amounts of the sunshine vitamin.
Individuals with Certain Diseases
There are many health conditions that can cause or exacerbate low vitamin D levels or vitamin D deficiency, or that are correlated with low levels, including cardiovascular disease, cancer, hypertension, and obesity. Digestive ailments like inflammatory bowel disease or celiac disease that impair nutrient absorption often affect the body’s ability to absorb dietary sources of vitamin D. It’s also common for people with digestive conditions to follow a diet that may not consistently provide the full spectrum of nutrients their body requires. Additionally, diseases that affect the liver can lead to low vitamin D levels.
Remedies for Vitamin D Deficiency
Like most health challenges, the best way to fix the issue depends on what's causing it. If you don't spend enough time in the sun, start finding time to do this. Take inventory of your nutritional intake. If you're not getting enough vitamin D in your diet (and there's a good chance you're not), either add foods that provide it or consider a supplement.
Most of us are conditioned never to leave the house without a thick coat of sunscreen. But a little sun on your skin isn't a bad thing. In fact, in order for your body to produce vitamin D, it's a necessary thing. You can help raise your vitamin D levels with relatively little exposure, it's not required to tan or burn. Of course, how much is enough (and how much is too much) depends on where you live, the time of year, and your skin tone. Experts suggest staying in the sun for about half the time it would normally take for you to turn a little pink. And, remember, the more skin you can expose to the sun's rays, the more vitamin D you'll produce.
Vitamin D Foods
- Fortified Orange Juice
- Fortified Milk and Yogurt
There are not many foods that are a good, natural source of vitamin D. Some types of fish and other animal-based food like liver, cheese, and eggs contain vitamin D, but it’s not a large amount and for people who follow a plant-based diet, those are not suitable options anyway. Some varieties of mushrooms provide vitamin D. Infant formula and processed food that’s been fortified with nutrients is another source of vitamin D. However, generally speaking, food, on its own, does not provide enough vitamin D for most people.
Vitamin D Supplements
Although the best source of vitamin D is your body's own production, it's not always easy to get a healthy serving of sunlight, especially during the winter months. But you can help maintain healthy vitamin D levels with supplementation. The Institute of Medicine recommends 600 IUs of D3 per day for most people – but suggests 800 IU for those over 70 years of age to help promote bone health. For those who are experiencing low vitamin D levels, healthcare experts may also recommend a supplement that provides 4,000 to 10,000 IUs. I recommend Global Healing's Vitamin D3 if you need a regular, consistent source of high-quality vitamin D that has 5,000 IUs per serving.
Often times vitamin D supplements are recommended for pregnant women and infant children to help bolster their vitamin D levels. Although there are general recommendations, it's best to rely on personalized guidance from a healthcare provider to determine the appropriate and healthy dose for your situation.
Can You Take Too Much Vitamin D?
While supplementation can help maintain sufficient vitamin D levels, be careful not to overdo it. Vitamin D is a fat-soluble vitamin. It is stored in the body's fat cells and can become toxic if levels grow too high, leading to a condition called hypercalcemia, which is a severe accumulation of calcium in the blood that may result in gastrointestinal distress and kidney issues. If you're taking more than 10,000 IUs per day, work closely with your healthcare provider to monitor your levels and ensure they stay in the healthy range.
What Nutrients Complement Vitamin D?
Considering the profound impact it has on one's health, vitamin D sounds a bit like a miracle micronutrient, but it does not work alone. Scientists have discovered that other vitamins and nutrients, including vitamin A, boron, zinc, vitamin K, and magnesium are instrumental in ensuring that vitamin D levels stay normal and consistent. It just goes to show that following a healthy, balanced diet that provides a complete fill of the recommended daily allowance of all nutrients is the best overall strategy to bolster your efforts to maintain optimal health.
Points to Remember
With so many studies touting vitamin D's role in maintaining good health and discouraging health ailments, it is important to make sure you have a healthy level of circulating vitamin D in your blood at every age and every stage of life. If you want to live life to the fullest – and avoid those nagging everyday aches and pains – a little bit of sunshine, a few tweaks to your diet, and the right vitamin D supplements can help ensure you are reaching your highest health potential.
- " Vitamin D Status: United States, 2001–2006." National Center for Health Statistics. The Centers for Disease Control and Prevention. Published Mar 2011. Accessed 12 Apr 2018.
- Jain, RB. "Recent Vitamin D Data from NHANES: Variability, Trends, Deficiency and Sufficiency Rates, and Assay Compatibility Issues." Journal of Advanced Nutrition and Human Metabolism. Published 2016. Accessed 22 July 2018.
- Haughton LA, Reinhold V. "The Case Against Ergocalciferol (Vitamin D2) as a Vitamin Supplement." The American Journal of Clinical Nutrition. Published 1 October 2006. Accessed 22 July 2018.
- Kato S. "The Function of Vitamin D Receptor in Vitamin D Action." J Biochem. 2000 May;127(5):717-722. Accessed 11 Apr 2019.
- "Niels Ryberg Finsen - Biographical." NobelPrize.org. Published 2014. Accessed 22 July 2018.
- "Vitamin D Linked to Autoimmune and Cancer Disease Genes, Underscoring Risks of Deficiency." Genome Research. CSH Press. Published 24 August 2010. Accessed 22 July 2018.
- "For Health Professionals: Position Statement on Supplementation, Blood Levels, and Sun Exposure." The Vitamin D Council. Accessed 22 July 2018.
- Kheiri B, et al. "Vitamin D Deficiency and Risk of Cardiovascular Diseases: A Narrative Review." Clinical Hypertension. BMC. Published 22 June 2018. Accessed 22 July 2018.
- Hollis BW, Wagner CL. "New insights into the vitamin D requirements during pregnancy." Bone Research. Nature. Published 29 August 2017. Accessed 22 July 2018.
- Forrest K, Stuhldreher W. "Prevalence and Correlates of Vitamin D Deficiency in US Adults." Nutrition Research. Science Direct. Published January 2011. Accessed 22 July 2018.
- "How Do I Get the Vitamin D My Body Needs?" The Vitamin D Council. Accessed 22 July 2018.
- News Staff. "IOM Updates Guidance on Vitamin D, Calcium." AAFP.org. Published 1 December 2010. Accessed 22 July 2018.
- "Vitamin D and Other Vitamins and Minerals." The Vitamin D Council. Accessed 22 July 2018.
†Results may vary. Information and statements made are for education purposes and are not intended to replace the advice of your doctor. If you have a severe medical condition or health concern, see your physician.