Vitamin D, Depression, and Gut Health – Is There a Connection?

Do you suffer from digestive symptoms but also find yourself feeling down at times? Or have you been diagnosed with depression?  It’s not a coincidence to have both depression and gut health conditions like IBS, SIBO, acid reflux and more – we see it all of the time in our clinic. 

It’s only natural to feel depressed to a certain extent when you’re dealing with gut issues. But many times feeling depressed and having GI issues may be directly related to your nutrition – specifically your vitamin D status.

We see vitamin D deficiencies quite frequently in our gut health clinic.  Because we get most of our vitamin D from sun exposure, we expect to see vitamin D deficiencies in the winter and especially in those who live in Northern climates.  But we do see low vitamin D status in clients who live in sunny and warm climates, too!  

And it’s no surprise to see so many clients who have vitamin D deficiencies because there is a correlation between vitamin D, depression, and gut health.  Vitamin D deficiency is very common and studies show that it’s more prevalent in those with gut issues(1). Depression can also show up in a number of other ways other than simply feeling blue – which we often uncover with our clients that suffer from gut issues.

There has been a well-established connection between the health of your gut and your mental health. This is known as the gut-brain axis, where clear communication takes place (or should take place) between the gut and the brain.

Studies have shown a large majority of people with depression or gut issues are deficient in vitamin D(2). In the clinic, Stacy and I often see clients with low or less than optimal vitamin D levels who may be experiencing depression-like symptoms.

Our client Samantha is just one example of someone who had been diagnosed with IBS and depression.  She had numerous food intolerances, struggled with diarrhea, plus she found it hard to focus at work.  After starting our work together, she was diagnosed with SIBO and vitamin D deficiency.  After a few months, Samantha not only resolved SIBO and her bouts of diarrhea but she quit her job to start graduate school.  Her mood improved and so did her ability to focus and concentrate.  Improving gut and mental health can be life changing and we were so thrilled for Samantha!

In this article, you’ll learn how vitamin D, depression, and gut health are all connected. You’ll understand why vitamin D is crucial for a healthy gut, and how to keep your vitamin D levels in a healthy range for a happier belly and mind.

Depression and Gut Health – the Gut-Brain Connection

There is a real connection between the health of our microbiome and our brain health. Our microbiome is the collection of both good and bad bacteria present in our digestive tract. The goal is always to have a balance of healthy little critters in our bodies to support optimal health.

Research has shown that when you have an unbalanced microbiome, such as in the case of IBS, SIBO, or reflux, it can negatively impact both your gut health and brain health.

This gut-brain connection is very strong so that when the gut is inflamed, the brain tends to be inflamed, as well(3). This inflammation may worsen if your vitamin D levels are low, and inflammation triggers bloat, diarrhea, and reflux.

To top it off, if you are already depressed, you may be more likely to develop a gastrointestinal infection or more chronic gut issues(4). In many cases, low vitamin D levels can increase the risk of infection (and depression) . This can create a vicious cycle that feels like an endless hamster wheel.

The good news is that keeping your vitamin D levels at a healthy range may help boost both your mood and support gut health, which may decrease unpleasant digestive symptoms(5).

Vitamin D and Depression

How do you know if you are depressed as opposed to having the typical “blues?”

Here are some symptoms of depression that we see in our clients:

  • Feeling down
  • Anxiety
  • Difficulty focusing or completing tasks
  • Loss of interest
  • Irritability
  • Decreased energy or fatigue
  • Insomnia or never feeling rested

These symptoms can also lead to a decreased appetite, disinterest, or apprehension around food for fear it will worsen digestive symptoms. All of which can increase the risk of additional nutrient deficiencies that can cause even more GI and mental health symptoms.

Studies also show that those with vitamin D insufficiency or deficiency have higher rates of mental health conditions(6). So even if you’re working on your mental health and going to therapy, it still may not address the entire problem if you are vitamin D deficient.

Vitamin D and Gut Health

Vitamin D is not just involved in supporting mental health, it also plays a direct role in the health of your gut. Low vitamin D levels can directly cause digestive problems, and digestive problems can also directly cause or worsen vitamin D deficiency due to increased inflammation or vitamin D malabsorption(7).

Since vitamin D is a fat-soluble vitamin, we need to include fat in the meal to absorb it. With gut issues such as IBS, inflammation in the intestines is common, which can affect vitamin D absorption.

Vitamin D helps protect the gut by maintaining the lining of the intestinal tract, keeping any dangerous particles from entering the blood stream.  If this barrier is not maintained, it can lead to a leaky gut and a buildup of bacteria that travels along the gut-brain axis, leading to the uncomfortable symptoms.

Vitamin D also increases the diversity of the microbiome, which plays a role in healthy digestive function, neurotransmitter production (hello good mood), and immune system regulation. And since up to 80% of our immune system is in the gut, it’s clear that by strengthening our gut, we can better support our immune system(8).

Vitamin D Deficiency – Diagnosis and Treatment

If you’re suffering from digestive distress and/or depression, we recommend getting your vitamin D levels checked. Ask your doctor to check your 25-hydroxy vitamin D or 25(OH)D levels. This is the most active form of vitamin D in the body and the most accurate measure of your levels.

Recommended vitamin D levels vary a bit per practitioner. We like to see vitamin D levels at 50 ng/mL or higher in order to prevent a future deficiency.  That’s right, your vitamin D may be “normal” according to the lab results but we find that it’s not optimal unless it’s close to 50 ng/mL. 

Our own bodies make vitamin D in our skin from sun exposure, which is the most effective way to get in our daily dose. This is also a big reason why we tend to feel so happy after getting sunlight – it’s all that vitamin D we’re soaking up!

However, it’s not always possible to get in enough sunlight depending on your schedule or where you live. We also don’t want to encourage long bouts of unprotected sun exposure since that can increase the risk of sunburns and skin cancer.  Plus, not everyone absorbs vitamin D from the sun effectively, depending on their genes(9).

Food Sources of Vitamin D

What about eating foods rich in Vitamin D?  Well, vitamin D is found naturally in only a few food sources. The best food sources of vitamin D include salmon, sardines, liver, egg yolks, and mushrooms. Vitamin K can also maximize the absorption of vitamin D, so eating your salmon with leafy greens like spinach and kale for the biggest benefit.

If you don’t eat these foods regularly, your best bet is to get regular sunlight if possible or take a supplement. If taking a supplement, look for Vitamin D3 coupled with Vitamin K2, which is the most effective at raising and maintaining vitamin D levels(10).

The specific dose will vary depending on your current vitamin D levels, diet, and medical status and should be discussed with your nutritionist and medical doctor.

Key Takeaways – Vitamin D, Depression, and Gut Health

Vitamin D levels, depression, and gut health are all interconnected and so when one is off, the others are likely affected. If you’re suffering from any mood or gut issues, ask your doctor to test your vitamin D levels, and check them regularly thereafter.

Eating vitamin-D-containing foods, getting sunshine when possible, and taking a vitamin D supplement can help support your mental health and the health of your gut.

Click here to save 15% on professional-grade, high-quality vitamin D supplements. These are the same supplements we use in our practice. Sign up for the discount and you’ll also receive a bonus – our How to Choose Supplements Guide!

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