If you’re at all familiar with vitamin D, it might seem like a deficiency in this vitamin is nearly impossible. After all, all we need to do to get enough vitamin D is step outside into the sunshine for 20 to 30 minutes or drink a glass of milk, right? The reality is more complicated. Although it might seem simple to ensure that you’re getting enough vitamin D, many people struggle with chronically low levels of this critical nutrient. Vitamin D can be found so commonly that many people end up taking it for granted, but a 2011 study by the National Health and Nutrition Examination Survey found that nearly 42 percent of American adults have insufficient levels of Vitamin D. Suddenly, things aren’t looking so simple anymore (1)!
What is Vitamin D?
Although seemingly ubiquitous, vitamin D is a fat-soluble vitamin that is actually found naturally in very few foods. Naturally, vitamin D is found in foods like fatty fish, including tuna, mackerel, and salmon, beef liver, cheese, and egg yolks, as well as foods fortified with vitamin D, including some dairy products, orange juice, soy milk, and cereals. That’s about it! Vitamin D can also be obtained from sun exposure.
Why Do We Need It?
Vitamin D is an incredibly important vitamin that our bodies need to function properly. When many people think of vitamin D, they think of its importance as it relates to bone growth, since vitamin D helps the body to absorb calcium. While most people know that vitamin D is essential to build strong bones, it also plays many other roles in the body. Besides assisting with the calcium absorption needed to build strong bones, vitamin D also plays other roles in our health:
- Helps minimize and reduce wrinkles and makes skin soft and smooth
- Helps reduce stress and tension, improving mental health
- May prevent certain cancers and other chronic disease
- Deficiencies can lead to seasonal depression/seasonal affective disorder (SAD) in areas or seasons with low exposure to sunlight
As the importance of vitamin D is increasingly understood, more studies are being conducted that link deficiency of vitamin D to a variety of serious health conditions, including breast cancer, prostate cancer, colon cancer, heart disease, depression, and weight gain (1). In addition to increasing our understanding on vitamin D deficiency and human health, researchers at the Vitamin D Society are also examining how vitamin D can be used to treat conditions like autoimmune disease, cancer, chronic pain, diabetes, high blood pressure, depression, osteoporosis, and neuromuscular diseases (2).
By the Digits
15mcg (600 IU): the average daily intake sufficient to meet nutritional needs of vitamin D, also known as recommended dietary allowance (RDA) (3).
46% DV: the percent daily value of vitamin D found in white mushrooms exposed to UV light (3).
0mcg: the amount of vitamin D found per serving in plant based foods such as apples, broccoli and bananas (3).
4000 IU: the safe upper limit of vitamin D; vitamin D is a fat-soluble vitamin, so it is recommended to consult with a healthcare professional before exceeded this amount (4).
Who is at Risk for Vitamin D Deficiency?
With so many Americans (about 42 percent) suffering from insufficient levels of vitamin D, it might seem like virtually everyone is at risk for deficiency. Because vitamin D is obtained from relatively few sources, this is true, but certain groups are more at risk of others. People who are at an increased risk for vitamin D deficiency include:
People Who Do Not Ingest Enough Vitamin D Over Time
The most common sources of vitamin D are from animal-based products, including fish, fish oils, fortified milk, egg yolks, and beef liver. Therefore, patients who adhere to a strict vegan diet or limit consumption of meat products are at an increased risk of vitamin D deficiency if they do not receive vitamin D from another source.
People With Limited Exposure to Sunlight
Whether you prefer to stay indoors and play video games, live in northern latitudes with limited sunlight hours, or you wear long robes or head coverings for religious reasons, limited exposure to sunlight is a major cause of vitamin D deficiency. The amount of sun exposure required to achieve sufficient levels isn’t terribly high - most people benefit from just 15 to 20 minutes a day of sun exposure - but this may be difficult if you have a medical issue or other circumstance that makes spending time in the sun difficult.
People With Darker Skin Tones
The more melanin, or pigment, that your skin has, the higher your risk of vitamin D deficiency. Melanin diminishes the ability of the skin to produce vitamin D in response to exposure to the sun, so older adults with darker skin are especially at risk of vitamin D deficiency.
People With Kidney Issues
Our kidneys play a vital role in helping our bodies convert vitamin D to its active form. Therefore, people with kidney illnesses or lower functioning kidneys are at increased risk of vitamin D deficiency.
People with Certain Digestive Issues
In order to use vitamin D effectively, our bodies must be able to absorb it from the food that we eat. People with conditions like Crohn’s disease, celiac disease, and cystic fibrosis are at an increased risk of vitamin D deficiency because their intestines may not be able to fully absorb vitamin D from the food they eat.
People Who are Overweight or Obese
Surprisingly, our weight can impact our bodies’ levels of vitamin D. Vitamin D is a fat soluble vitamin that is extracted from the blood by fat cells, which alter its release into our circulatory systems. People with a body mass index (BMI) of 30 or greater are often found to have low levels of vitamin D.
Signs of Vitamin D Deficiency
Vitamin D is an extremely important vitamin for many bodily functions, but many people don’t realize that they are deficient because the signs and symptoms are often subtle. Common signs of vitamin D deficiency include (5):
Fatigue or Exhaustion:
Low blood levels of vitamin D have been linked to severe fatigue in many case studies, but researchers have also found that vitamin D levels do not have to be extremely low in order to have a major impact on energy levels (6).
Low levels of vitamin D have been linked to depression in all ages, but older adults are especially at risk.
Loss of Bone Density:
Vitamin D helps the body to absorb calcium and metabolize bone, and without it, low bone mineral density can result. Patients often supplement with calcium when they find out they have low bone density, but many are also deficient in vitamin D. Older adults, especially women who have experienced menopause, are especially at risk for low bone mineral density.
Not many people think of muscle pain as a symptom of vitamin D deficiency, but one study found that 71 percent of people with chronic muscle pain were found to be deficient in vitamin D (7). Taking vitamin D supplements can help to reduce muscle pain in children and adults found to be deficient.
If it feels like you’re one of those people who is always getting sick, you might have low levels of vitamin D. Vitamin D plays a vital role in keeping the immune system strong, so without it, you’re much more likely to get sick.
Bone and Back Pain:
People with vitamin D deficiencies were more likely to have back pain, including severe back, than those who did not, according to one study (8). Another study found that people with vitamin D deficiencies were almost twice as likely to have bone pain in their joints, ribs, or legs than those who had normal levels of vitamin D (9).
If you experience slow wound healing times or struggle to recover from injury, you may have low levels of vitamin D, which is critical in controlling inflammation and fighting infection. People with significant vitamin D deficiency showed higher inflammatory markers than normal levels, which can jeopardize healing (10).
Severe hair loss, such as that caused by alopecia areata, is linked to low vitamin D levels. People with low levels of vitamin D may be at increased risk of developing alopecia areata, which is an autoimmune disorder, or suffering from other forms of severe hair loss.
How Can I Correct a Vitamin D Deficiency?
The best way to correct a vitamin D deficiency is by consuming vitamin D from real food sources and through healthy exposure to the sun. If you’re unable to consume vitamin D rich foods due to dietary restrictions, whole-food supplements like GEM contain black chia seeds and agaricus bisporus mushrooms, both of which are rich in vitamin D. Of course, spending a little more time in the sunshine when possible (safely, of course!) is another great way to boost your vitamin D intake and also enjoy some fresh air while you’re at it. People living in places with limited sunlight during certain seasons will also benefit from taking a nutrient-dense vitamin.