The link between vitamin D and mental health

Maybe you’ve been feeling depressed and don’t know why. Or you might be going to therapy and taking antidepressants but still don’t feel like yourself. One possible reason is low vitamin D levels. Many people don’t realize there’s a strong connection between vitamin D and mental health. 

Even though vitamin D deficiency is common, most doctors don’t check for it in standard blood tests. Usually, they only order a vitamin D test if you have risk factors like bone problems, little sun exposure, or certain health conditions.

If you notice symptoms of vitamin D deficiency or belong to a higher-risk group, it may be a good idea to ask your doctor about getting your levels checked.

What does vitamin D do for mental health?

Vitamin D deficiency can look a lot like depression. The two share many of the same symptoms, which makes it easy to confuse them. You might feel tired all the time, notice mood swings, have trouble focusing, or struggle with sleep. Because these are also common signs of depression, many people don’t realize that low vitamin D levels could be part of what’s causing them to feel this way.

That’s why some doctors and therapists recommend checking vitamin D levels in people who don’t respond to antidepressants or have unexplained fatigue or mood changes. Correcting a deficiency through sunlight, diet, or supplements can often improve these symptoms.

Certain groups of people are more likely to have low vitamin D levels, including:

• Older adults: As people age, their skin becomes less efficient at making vitamin D from sunlight ^[3], so adults older than age 65 are at higher risk of vitamin D deficiency even if they spend time outdoors. 

• People with darker skin: Higher levels of melanin reduce the skin’s ability to produce vitamin D from sunlight.

• People with certain medical conditions: Digestive disorders, like Crohn’s and celiac disease, and kidney or liver problems can interfere with vitamin D absorption and activation. Also, people with obesity or who have undergone gastric bypass surgery may need more vitamin D. 

• Vegetarians and vegans: People who don’t eat fish, eggs, or fortified dairy products are more likely to have lower vitamin D levels.

How does vitamin D deficiency impact mental health?

Vitamin D helps regulate serotonin, a brain chemical that stabilizes mood. When your vitamin D levels are low, your body may make less serotonin, which can make depression harder to manage.

Because vitamin D supports mood, thinking, and how you handle stress, having a deficiency can mimic or worsen mental health symptoms and conditions like: 

• Anxiety: Low vitamin D is linked to higher rates of anxiety ^[4]. Some research ^[2] suggests that vitamin D supplements may ease anxious feelings.

• Panic attacks: Studies ^[2] show that people who experience panic attacks are more likely to have low vitamin D. Taking vitamin D supplements ^[5] can reduce how often panic attacks happen and how strong they feel.

• Seasonal affective disorder (SAD): This type of depression comes and goes with the seasons. It typically begins in the fall and continues through the winter months. SAD is tied to less sunlight and reduced vitamin D ^[6]. 

• Bipolar disorder: People with bipolar disorder are more likely to have low vitamin D ^[7]. Because vitamin D helps regulate mood, a deficiency can make mood swings and depressive episodes worse. 

• Poor cognitive functioning: Low levels of vitamin D are linked with problems like difficulty concentrating, slower thinking, and even a higher risk of dementia ^[8] in older adults.

Additionally, if you’re already taking antidepressants or going to therapy, low vitamin D can make it harder for your brain to fully benefit from treatment. Research ^[9] shows that adding vitamin D to antidepressants may improve their effectiveness and make it easier to manage depression. 

Managing vitamin D deficiency and emotional struggles

Many people with vitamin D deficiency don’t have obvious symptoms. However, if you’re experiencing persistent fatigue or depression, it’s a good idea to ask your doctor for a blood test.

If your test confirms low vitamin D, some safe and effective ways to raise your levels include: 

• Taking supplements: Talk to your doctor about vitamin D3, which works better than D2 ^[10] because the body can absorb it better. Vegan people can now get natural D3 supplements made from lichen, a plant source. Most people need between 600 and 2,000 international units (IU) daily, but some require more. Always check with your doctor about the right dose for you.

• Getting sunlight: Aim to spend 5 to 30 minutes in the sun ^[11] between 10 a.m. and 4 p.m. most days of the week with your face, arms, legs, or hands uncovered. If you’re worried about skin cancer, even 5 or 10 minutes can help boost your vitamin D levels, or you can rely more on supplements and food.

• Eating vitamin-D rich foods: Try to include certain foods — like fatty fish, egg yolks, fortified and plant-based milks, fortified yogurt and breakfast cereals — in your diet.

• Seeking support: Low vitamin D can cause mood swings, anxiety, and sleep problems. A therapist can help you track symptoms, notice patterns, and figure out whether they may be linked to low vitamin D or other lifestyle factors. They can also help you build healthy routines for sleep, exercise, and getting outdoors, all of which can support vitamin D levels.

Clinician’s take

To support healthy vitamin D levels, I would talk to your provider. However, some simple tips include getting outside more often, eating healthy foods with vitamin D in them, and supplementing with D3 pills. Then, it’s important to follow up with your provider to get blood work done.

Halee Fullerton, PMHNP-BC

Clinical reviewer