Ah, the sunshine vitamin. It’s usually all around you—at least during the daytime and more so during the summer months. It’s also in certain food and drinks like sardines and orange juice (usually known more for its vitamin C content, but also rich in vitamin D) and in supplements like cod liver oil.
But how do you know when you’re getting enough of this vitamin, and how much vitamin D do you need? That's a question that doesn't have a straightforward answer. The amount you need of the nutrient depends on many factors, including your age, your health, and sun exposure.
Why does it matter? Well, vitamin D plays many vital roles, including maintaining bone health and preventing certain diseases. Even if you don’t have a vitamin deficiency, low vitamin D levels can put you at an increased risk of certain health conditions.
Most people get the vitamin D they need from exposure to sunlight, but if you don't spend enough time outdoors or wear too much sunscreen, you may not be getting enough of this vital nutrient. Read on
What Is Vitamin D Deficiency?
We know now that the sunshine vitamin is an essential nutrient. It helps your body absorb calcium and phosphorus and lowers your risk of conditions like osteomalacia (when your bones soften because of a vitamin D deficiency) and multiple sclerosis.
While vitamin D deficiencies may not cause very noticeable symptoms, they can lead to many health problems down the road.
Unfortunately, vitamin D deficiency is all too common, particularly in colder climates during the winter months when you have less exposure to sunlight. When you expose your skin to sunlight, it produces vitamin D.
However, many people do not get enough sun exposure to meet their vitamin D needs for various other reasons. These factors include working indoors, wearing too much sunscreen, or genetic predispositions like having more melanin.
Healthcare professionals often recommend supplements to help mitigate a vitamin d deficiency. Still, experts suggest that getting regular sunlight exposure may be the best way to ensure adequate levels.
Some recommendations suggest spending 10 to 15 minutes in the sun each day without sunscreen to allow your body to produce its vitamin D. This also depends on the time of year and the angle of the sun. For example, UVB rays are insufficient for vitamin D production in many parts of the US between October and March.
Common Symptoms of Vitamin D Deficiencies
People most at risk for vitamin D deficiency include those who don't get enough sun exposure. People with health conditions like obesity or certain medical conditions that make it difficult to absorb vitamin D are also at risk.
If you think you might be deficient in vitamin D, talk to your healthcare provider about getting a blood test. A lack of vitamin D can lead to various health conditions, including:
- A weakened immune system
- Depression
- Fatigue
- Muscle weakness
- Bone pain
- Increased sensitivity to cold
- Impaired cognitive function
- Bone pain
- Osteoporosis
- Increased risk of heart disease
- Muscle pain
- Hair loss
In severe cases, low vitamin D levels can lead to Rickets, a condition that, like osteomalacia, causes softening and deformities of the bones.
Can Medications Cause Vitamin D Deficiency?
Yes, certain medications can cause a vitamin D deficiency. These include corticosteroids, anticonvulsants, and certain heart medications. Recent research has found that certain medications can interfere with the body's ability to absorb vitamin D, leading to a deficiency.
Medications with links to vitamin D deficiency include:
- Steroids
- Seizure controlling drugs like colestipol
- Laxatives
- Cholesterol-lowering medications
- Weight loss medications
Diagnosing a Vitamin D Deficiency
Since it’s most accurate to check vitamin D in your blood levels, it’s no surprise that a vitamin D deficiency is usually diagnosed through a blood test. The test measures the level of a substance called 25-hydroxyvitamin D in the blood. This substance is a form of vitamin D produced in the liver and then stored in body fat.
A vitamin D deficiency is typically defined as a level of 25-hydroxyvitamin D that is lower than 12 ng/mL. Levels that are measured as 50 ng/mL or more are too high and can cause risks to your bone health. In addition to a blood test, a doctor may also perform a physical exam and take a medical history to diagnose a vitamin D deficiency.
Can You Get Too Much Vitamin D?
Your body needs vitamin D to absorb calcium and promote bone growth. Historically, the primary way people get vitamin D has been to spend some time in the sun. However, today, many people are worried about the risks of skin cancer, so soaking up the sun may not be as enticing an option as it once was.
As a result, they may not be getting enough vitamin D. At the same time, it's also possible to get too much vitamin D. This can happen if you take supplements or spend too much time in the sun. Vitamin D toxicity can cause nausea, vomiting, and weakness. In severe cases, it can lead to kidney damage and sometimes be fatal.
Vitamin D and Blood Glucose Levels
Before you add orange juice and sardines to your daily diet to boost your vitamin D, what about it’s connection to blood glucose? A growing body of evidence suggests that there may be a link between vitamin D and your blood sugar levels. We’ve learned vitamin D is a crucial nutrient for maintaining strong bones and muscles, and it also plays a role in immune function and cell growth.
However, recent studies have shown that vitamin D may also help regulate blood sugar levels. One study found that people with diabetes who were given a high dose of vitamin D were less likely to experience fluctuations in their blood sugar levels. While research is still ongoing, the evidence so far suggests that vitamin D may play some role in blood sugar control.
Researchers have recently explored links between vitamin D deficiency and other conditions, such as diabetes and high blood pressure. Some studies have suggested that vitamin D may play a role in regulating blood sugar levels.
One theory is that vitamin D helps the body use insulin. This hormone helps the body process sugar more efficiently, so those with diabetes may benefit from supplements or increased sun exposure.
Adjusting Your Diet to Get More Vitamin D
The best way to get Vitamin D is by spending time in the sun, as the body produces it when exposed to sunlight. However, for those who don't have much exposure to sunlight, there are other sources of vitamin D, including food sources.
Fatty fish such as salmon, sardines, mackerel, and tuna are excellent sources of vitamin D. Egg yolks, mushrooms, and fortified milk also contain small amounts of this nutrient. You can also take a vitamin D supplement like cod liver oil to ensure that you get enough of this vital nutrient. Still, it’s typically best to consult with a doctor before adding any supplements to your diet.
By including these foods in your diet, you can help to ensure that your body gets the vitamin D it needs to stay healthy. However, remember that it’s best to work with a credentialed dietitian or nutritionist before adding or cutting foods out of your diet to ensure you’re staying healthy.
What Is a Typical Recommendation for Vitamin D?
While it's true that the amount of vitamin D you need depends on various factors, some general guidelines can help you determine if you need more of this essential nutrient.
For instance, the National Institutes of Health recommends that adults under 50 should consume 600 IU (international units) of vitamin D per day. In comparison, those over 70 should consume 800 IU per day.
However, these recommendations assume that you have adequate sun exposure. If you're not getting enough sunlight, you may need to increase your vitamin D intake.
Another factor to consider is your age. As you age, your skin becomes less efficient at producing vitamin D in response to sun exposure. It means that older adults may need an added multivitamin, supplement, or more vitamin D-rich foods in their diets.
Health Benefits of Getting Enough Vitamin D
We’ve seen what constitutes a vitamin D deficiency, how to treat it, and what you can do to increase your vitamin D levels. If you’re still curious about the specific health benefits it has, here are a few reminders:
- It may reduce your risk of autoimmune conditions like multiple sclerosis.
- Vitamin D deficiencies can cause bone pain and muscle weakness, leading to osteomalacia and osteoporosis. So, naturally, vitamin D reduces your risk of these conditions.
- Vitamin D can also reduce the risk of health conditions like cancers and heart disease.
- Low levels of vitamin D may lead to cognitive issues. To keep your brain healthy, you have to ensure you’re getting enough vitamin D.
- If you don’t get enough vitamin D, you can increase the risk factors for inherited bone disorders like familial hypophosphatemia.
- Vitamin D can also help with skin conditions like psoriasis.
Check out our post on Instagram for our Nutrition Team's tips to get more vitamin D, and stay tuned for more on how to modify your diet to add in vitamin D-friendly foods.
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to help you discover and reach yourHeather is a Registered and Licensed Dietitian Nutritionist (RDN, LDN), subject matter expert, and technical writer, with a master's degree in nutrition science from Bastyr University. She has a specialty in neuroendocrinology and has been working in the field of nutrition—including nutrition research, education, medical writing, and clinical integrative and functional nutrition—for over 15 years.