Vitamin D plays a unique and important role in your body. It is the only vitamin that functions just like a hormone, connecting to a few different key systems in your body and playing an important part in their function.
When vitamin D enters your body through the sun on your skin or is consumed through food or a supplement, it goes straight to your liver and kidneys, where it is converted into a hormone. This hormone is usually referred to as “activated vitamin D” or “calcitriol.” Then, it helps your body absorb calcium — an essential task for your bones and teeth — and activates genes that influence your immune system as well as your brain. Every tissue in the human body has vitamin D receptors, so this particular vitamin is pretty important.
It is estimated that 70% of the United States population has a Vitamin D deficiency. What happens when there isn’t enough vitamin D to go around? When there is not enough vitamin D, the areas of your body that rely on this nutrient can begin to deteriorate or change, causing a variety of problems. A few of the first vitamin D deficiency symptoms you notice may include constantly being sick, having muscle or bone pain, feeling exhausted or down, losing hair or bone mass, and wounds that are slow to heal.
While vitamin D deficiency can have a severe impact on your health, it is relatively easy to avoid or remedy in most cases. The first step in treating a vitamin D deficiency is educating yourself, so you understand the importance of this essential vitamin, what to look for and what you can do to improve your vitamin D levels.
What Does Vitamin D Do?
Vitamin D has a few significant roles in your body. Most prominently, it serves as a catalyst for the absorption of calcium. Without vitamin D, your body cannot absorb calcium, leaving teeth and bones weak and frail. In addition to this, vitamin D also helps regulate the immune system and the release of neurotransmitters, like dopamine and serotonin. These neurotransmitters affect brain function and development — and consequently, your mental health. Receptors for vitamin D have been found in regions of the brain that are also linked to depression.
How Much Vitamin D Do You Need?
Guidelines for vitamins are often set by the Health and Medicine Division (HMD) of the National Academies — formerly known as the Institute of Medicine (IOM). These guidelines come in the form of recommended dietary allowances (RDA), in a measurement of international units (IU). You may recognize the IU abbreviation from the back of vitamin containers, as that is the measurement that is frequently used to show how much of a vitamin is present in a supplement.
The HMD recommends 600 IU of vitamin D per day for all ages, beginning at one-year-old through 70 years old. The RDA increases to 800 IUs per day for people who are older than 70 years of age.
How Is Vitamin D Produced or Digested?
There are two types of Vitamin D — D2 and D3. Vitamin D2 is ingested through food or a supplement. Vitamin D3 can also be taken as a supplement and is found in small amounts in food, but D3 is naturally created from a chemical reaction that occurs when your skin is exposed to the sun, specifically, ultraviolet B rays of sunlight.
Regardless of whether you have Vitamin D2 or D3, and whether it is produced or ingested, the result is the same — it binds to a protein that transports it to the liver. When Vitamin D reaches the liver, another chemical reaction occurs, turning it into a chemical called calcidiol, which functions as a hormone.
What Causes a Vitamin D Deficiency?
A Vitamin D deficiency can be caused by a number of factors, many of which are beyond your control. Even though you may not be able to change the factors that make you more susceptible to a vitamin D deficiency, it is still helpful to know if your age, skin tone, weight, health, exposure to the sun and various medications could put you at a higher risk of vitamin D deficiency. Here are some of the main causes:
- Limited Exposure to the Sun: If your skin is not exposed to the ultraviolet rays of the sun, the chemical reaction that produces Vitamin D in the skin does not occur, reducing the amount of Vitamin D in your body.
Skin Tone: People with darker skin tones absorb less ultraviolet rays. Therefore, their Vitamin D supply from sun exposure is less than people with lighter skin. To achieve the same level of Vitamin D production from sunlight, people with darker skin tones need three to five times longer exposure to the sun than people with lighter skin tones.
- Being Overweight: Studies have shown a clear connection between obesity and Vitamin D deficiencies, but the exact reason why has yet to be determined. One scientific conclusion is that the fat under the skin traps the vitamin instead of releasing it to travel through the bloodstream to the liver.
- Malabsorption syndromes: If you have Crohn’s disease, cystic fibrosis, celiac disease, or another malabsorption syndrome, your body’s digestive tract can’t absorb vitamin D from the food you eat, making it tough to get the recommended amount this way.
- Age: As you age, many bodily functions begin to slow down, one of them being the production of Vitamin D. Senior citizens also tend to spend more time indoors, limiting their exposure to the sun, but their bodies also produce less vitamin D as a result of sun exposure.
- Certain Medications: Since the production of vitamin D has so many moving parts, medications can affect one or more steps in vitamin D production or processing and cause a deficiency. For example, medications that treat high cholesterol affect body fat, which stores and releases Vitamin D. Anti-seizure medications have been found to transform the vitamin into an inactive form, rendering it useless for the body. In addition to these types of medications, there are others that have been found to affect the production of Vitamin D, but the exact effect is not yet well understood. Talk to your doctor for more information.
What Are Vitamin D Deficiency Symptoms?
There are several symptoms of vitamin D deficiency that you may be experiencing. A few of the most common signs of a vitamin D deficiency include:
- Frequent Illnesses or Infections: We have mentioned that vitamin D helps regulate the immune system, which is your body’s defense against viruses and bacteria. Therefore, it makes sense that one of the vitamin D deficiency symptoms is being sick often and having an increased risk of infections. When your primary defense is down, your risk for illnesses and infections is up.
- Excessive Fatigue: Fatigue caused by vitamin D deficiency is another symptom, especially in women. Studies have discovered a vitamin D deficiency in women who were suffering from excessive tiredness. This is likely due to vitamin D’s role in brain chemistry.
Backaches and Pains: One of the primary functions of vitamin D is to facilitate the absorption of calcium, which is essential for your bones. When there is a lack of vitamin D, less calcium is absorbed, resulting in joint and back pain.
- Bone Loss or Hair Loss: In addition to aching bones, a lack of vitamin D and subsequent lack of calcium can cause your bones to deteriorate, leading to fragile bones that break frequently. In addition to losing bone mass, severe hair loss is also suspected to be a vitamin D deficiency symptom — there have been confirmed cases of people with hair loss that also have lower levels of vitamin D, but the research in this area is still pretty limited.
- Muscle Pain: While the causes of muscle pain are tough to determine, the fact that receptors for vitamin D are found in nerve cells means there is reason to believe the two are connected. We know that vitamin D deficiency is connected to pain and sensitivity, which makes a strong case for vitamin D deficiency being the cause of some chronic muscle pain.
- Depression or Other Mental Health Issues: The link between sunlight and depression has been recognized for thousands of years. Today, we know that connection exists because vitamin D influences the release of dopamine and serotonin, two neurotransmitters that play a prominent role in your mental health. Depression and other mental health issues are complex, and while vitamin D deficiency is thought to be linked to depression, research has yet to determine if vitamin D could prevent these mental health issues.
What Are the Vitamin D Deficiency Effects on Mental Health?
Vitamin D receptors in the brain prove that this particular vitamin affects your mental health. It’s believed to influence proteins in your brain that play a role in everything from your mood to social behavior. While studies are still being done to pinpoint exactly how vitamin D affects specific mental health issues, there are a few that are already documented.
Vitamin D Deficiency and Depression
We all notice when the days get shorter, but for some people, this also marks the beginning of a season of depression. Vitamin D3, the type that is produced through a chemical reaction in your skin due to sun exposure, is lacking when the days are shorter — and so is our positive energy. In fact, scientists have discovered that people with vitamin D deficiency symptoms are 11 times more likely to be depressed than those with normal levels. Yes, the connection here is strong, but there are several other possible causes of depression as well — adrenal fatigue, hormone imbalance, environmental factors, etc. While there’s a good chance vitamin D deficiency plays a role, it is important to take all of these factors into consideration when considering diagnosis and treatment.
Vitamin D Deficiency and Anxiety
One type of depression, seasonal affective disorder (SAD), is closely tied to seasonal changes and sunlight exposure — hence its name. While it is considered to be a type of depression, symptoms may lead to or include feelings of anxiety. For example, people with a seasonal disorder may be irritable and suffer from insomnia — both related to anxiety. Someone may not begin with feelings of anxiety, but these feelings can develop from the same lack of sunlight and vitamin D3 that may be linked to depression.
While there can be a link between vitamin D deficiency and anxiety, it is also important to note there can be other reasons patients with anxiety have low levels of vitamin D. For example, exercising and spending time with friends are two lifestyle activities that often occur outdoors. People with anxiety often avoid both of these activities — limiting their exposure to the sunlight and production of vitamin D3, but not causing their anxiety.
Vitamin D Deficiency and Other Mental Health Issues
In addition to depression and anxiety, vitamin D deficiency affects other mental health issues as well. A group of Dutch researchers conducted a study on adults in outpatient care for bipolar disorder, schizophrenia and schizoaffective disorder. They found that vitamin D deficiency was 4.7 times more common in the adults with bipolar disorder, schizophrenia or schizoaffective disorder when compared with the general population. The role that vitamin D plays in the brain explains why there are several links between a vitamin D deficiency and mental health issues. While not all of them are fully understood, the correlation is undoubtedly present.
Other Effects of Vitamin D Deficiency
Mental health isn’t the only area of your life that can be impacted by a vitamin D deficiency. If left untreated, the deterioration of bone tissues over time due to a lack of vitamin D, and subsequently, calcium, can lead to osteoporosis in adults and rickets — also known as bone weakening — in children. Chronic back pain, sometimes as a result of bone loss, can also develop if your bones aren’t getting the calcium they need.
Equally as concerning is the effect a vitamin D deficiency can have on your immune system. A weakened immune system leaves your body’s primary defense down, increasing your risk for a variety of illnesses, but especially the flu, asthma and other respiratory infections. These infections are not good for anyone, but they are particularly dangerous for the elderly.
Good Sources of Vitamin D
Being aware of your vitamin D levels can help prevent both physical and mental health issues that can be caused by a vitamin D deficiency. You can begin by determining your level of vitamin D through a blood test.
Once you know how your level of vitamin D compares to what your doctor recommends for your age and health needs, you can take steps to increase your vitamin D intake. How? There are several different ways you can give your level of vitamin D a lift:
Take a Supplement: Supplements are probably the easiest solution for anyone who is concerned about having low vitamin D levels. Supplements are easily accessible and can be taken once per day to give you a vitamin D boost.
Get out in the Sun: Increasing your exposure to the sun is the best way to get vitamin D3. While sunscreen blocks the ultraviolet rays that cause the chemical reaction, you have to be careful spending time in the sun without it. Make sure you don’t forget to apply sunscreen if you’re planning to be out in the sun for longer than 15-20 minutes — you don’t want a sunburn along with your vitamin D.
Eat Foods That Are Rich in Vitamin D: While getting more sun and taking a vitamin D supplement are both great ways to boost your numbers, there are foods with vitamin D that you can begin to incorporate into your diet as well. Many of these foods are good for your health in other ways, so adding them to your meal plan will provide several benefits. We have included some of our favorite foods with vitamin D below, along with the approximate amount of vitamin D in each. Don’t forget, the HMD recommends a total of 600 IU of vitamin D every day for the average person.
- Egg Yolks: Each egg yolk contains approximately 41 IU of vitamin D. Eating egg yolks doesn’t have to mean restricting yourself to choosing between over easy and scrambled at breakfast, there are a variety of ways you can incorporate egg yolks into your diet to give your vitamin D intake a boost.
- Fish: When it comes to fish, wild-caught mackerel is your best bet with 547 IU in a three-ounce portion. Wild-caught salmon is a close second, coming in at 425 IU per three-ounce portion. You will still get some vitamin D with farm-raised salmon and mackerel, but not as much.
- Shiitake Mushrooms: If you can find a way to incorporate one cup of Shiitake mushrooms into a dish you are making, you can bump your daily vitamin D intake up by 40 IU.
Milk: Drinking one eight-ounce glass of whole, reduced fat or nonfat milk has 100 IU of vitamin D. As a bonus, milk also gives you a calcium boost.
- Yogurt: Speaking of a calcium boost, yogurt also gives you calcium along with its 80-100 IU of vitamin D in each six-ounce portion. Individual yogurt portions vary, so you may be pleasantly surprised to find your favorite brand has a larger serving size, further increasing your vitamin D intake.
- Almond Milk: Not a big fan of dairy? No problem. Substitute almond milk and you’ll still get 100 IU of vitamin D in one eight-ounce glass.
Oatmeal: In just one packet of oatmeal, you can get 150 IU of vitamin D. Use milk, and you’ll have the benefits of additional vitamin D and calcium.
- Cheese: In one slice of cheese, you can expect to get 40 IU of vitamin D. How often do we eat just one slice? Increasing your vitamin D is a great excuse for a more generous portion.
- Orange Juice: This juice may not have the same amount of calcium as milk, but it boasts 137 IU of vitamin D in just one eight-ounce glass, putting it a step above a glass of milk.
- Breakfast Cereal: If you aren’t a big fan of eggs for breakfast, you can start your day with one cup of cereal and get up to 100 IU of vitamin D. Add a full glass of milk to your cereal bowl, and you are on a roll.
Why Healthy Levels of Vitamin D Matter
Vitamin D plays a role in several integral parts of your body — your brain, bones, and muscles. While the exact role vitamin D plays may not be understood in all of these areas, research shows that a vitamin D deficiency can hurt your health in many ways. To ensure that you’re doing everything you can to maintain an optimum level of health, the HMD recommends that the average person get at least 600 IU of vitamin D every day — ideally from a combination of exposure to sunlight (vitamin D3) and food or supplements (vitamin D2).
If you think you may have symptoms of a vitamin D deficiency, you can talk with your doctor about getting a blood test to confirm your vitamin D levels. If you discover your vitamin D levels are low, you can make a note of some changes you can make to increase your vitamin D intake and talk to your doctor about any additional treatments that may be needed for your particular symptoms.