5 Sneaky Signs You Might Have a Vitamin D Deficiency

As far as vitamins and nutrients go, vitamin D has been pretty on-trend. This could be due to the robust research behind all of its potential health benefits, from supporting healthy bones and reducing inflammation to lowering the risk of depression. But what actually is vitamin D? And how do you know if you're falling short on your needs? Here we dive into the science behind how much vitamin D you actually need, plus five sneaky signs you might be deficient.

How Much Vitamin D Do You Need Each Day?

Vitamin D helps with calcium absorption, which is important for healthy bones and muscles. It also can help reduce inflammation, support a healthy immune system and more. It is recommended that adults between ages 19 and 70 get 600 IUs (or 15 mcg) of vitamin D per day. One of the main ways we get this vitamin is through sun exposure. Our skin can create sufficient vitamin D from approximately 5 to 30 minutes of sun exposure to our face, arms, hands and legs daily (or at least twice per week), but this can vary significantly based on where you live.

There are also several food sources of vitamin D, including eggs, salmon, sardines, yogurt, milk, tuna, UV-exposed mushrooms and fortified foods (like orange juice and breakfast cereal). Additionally, vitamin D supplements from reliable brands, like NatureMade and Garden of Life, can help you meet your needs.

5 Signs You Might Have a Vitamin D Deficiency

1. You're Feeling Depressed

One exciting area of research is focused on how vitamin D levels can affect mental health, specifically depression. In a 2020 review published in the Indian Journal of Psychological Medicine, researchers concluded that serum vitamin D levels inversely correlated with clinical depression, meaning the lower your vitamin D levels, the more likely you were to be depressed. Vitamin D deficiency might be a factor if you are feeling down more often than usual, especially during the winter months (looking at you, seasonal affective disorder). The good news is, upping your intake might help improve some symptoms.

A 2019 study published in the Journal of Postgraduate Medicine found that vitamin D supplementation favorably impacted self-reported depression ratings in participants. However, a 2021 review in the Journal of Clinical Medicine had inconclusive results, so more research is needed to clarify vitamin D's relationship with mental health. As always, talk with your doctor before starting any new supplement. Your doctor might also be able to check your serum vitamin D levels to see if you're deficient.

2. You Live in a Cold-Weather Climate

As mentioned, our bodies can make vitamin D from exposure to the sun. However, the sun has to have a high enough UV index (about 3 or above) in order for our bodies to be able to do this. We also have to have enough skin exposed—which doesn't often happen in the winter. In places with a long, cold winter, say, Vermont, there are only a few months of the year where making enough vitamin D from the sun is viable. If you are curious about this, the app Dminder can help you track the specific amount of vitamin D you are getting from the sun based on the UV index, time of day, amount of sun exposure and more.

3. You Have Weak Bones

This could be the most obvious sign that you might not be meeting your vitamin D needs. The vitamin is crucial for healthy, strong bone formation. If you routinely experience bone breaks or stress fractures, you could be vitamin D deficient. If you are experiencing any of these symptoms, talk to your doctor to see the best course of treatment and to learn if a vitamin D supplement could be right for you.

4. You Have High Blood Pressure

While the connection between vitamin D and bone health is well established, the connection between vitamin D and heart health is less clear. Studies like the 2020 review published in Preventing Chronic Disease have found inconclusive results about whether vitamin D supplementation can help lower high blood pressure. More research is needed to clarify the relationship between vitamin D and blood pressure. If you have high blood pressure and think you might be deficient in vitamin D, talk to your doctor to see if testing your vitamin D levels is appropriate.

5. You Follow a Vegan Diet

Unfortunately, most food sources of vitamin D come from animal products such as eggs, fish and dairy. Avoiding these foods can put you at a higher risk of deficiency. But it's not impossible to meet your needs if you follow a vegan diet. It might take some extra planning, but there are plant-based ways to get your 600 IUs in per day. Include vegan-friendly food sources of vitamin D such as UV-exposed mushrooms, fortified orange juice and fortified breakfast cereals. Also, try to spend some time outdoors each day, especially if you live in a warmer climate.

The Bottom Line

Vitamin D is involved in various important body functions, from bone health to brain health and more. But meeting your needs can be easier said than done, especially if you follow a vegan diet or live in a colder-weather climate. Feeling more depressed than usual or having high blood pressure might be symptoms of an underlying deficiency. If you are concerned about your vitamin D levels, talk to your doctor or a dietitian about a serum vitamin D test or to see if supplementation is right for you.