Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In


Mood & Stress

The Mood-Boosting Effects of Probiotics

Probiotics can do more than improve your gut health—they may also improve your mood. Learn about the gut-mood connection and the nutrients that can make a difference in your emotional well-being.

Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.

If there were a magic pill that could make you happier, would you take it? You might wonder if the pill caused side effects—pills often do. But in this case, there are no side effects. There’s actually the side benefit of becoming healthier. That’s a slam-dunk, right? People would line up around the block for that pill. The crazy part is, that drug exists, just not in pill form. The technical name for it is diet. We often think of healthy eating for the metabolic benefits. But there’s a growing body of evidence that this simple approach can support positive mood.

Gut Bacteria and Mood

Your digestive tract does a lot more than digest. It’s the first line of defense for the immune system, protecting your body from harmful invaders. It also has a major impact on neurological health. The gut secretes hormones that influence the brain. In fact, there’s a steady feedback loop between the brain and the GI system. The gut also contains a number of neurotransmitters, like serotonin, that influence mood.

Some of the most exciting new research centers around the role that the many microbes in the digestive tract play in promoting mental health. Some researchers are calling it the “microbiota-gut-brain axis.” Hundreds of different species of bacteria, fungi, and viruses are the body’s constant companions, and everyone has their own unique microbial forest, or microbiome. These microbes help digest food, produce necessary vitamins, and work in concert with your immune system to protect against pathogens. The good bugs aren’t necessarily altruistic, though—they’re definitely looking out for their own best interests. It’s just that humans have co-adapted in a way that makes their interests align with ours.

This relationship begins at birth. Infants acquire their first microbes while traveling
through the birth canal. Scientists are trying to figure out how to get those same microbes into babies born by caesarian, since research has shown that babies born without the benefit of birth canal microbes have an increased risk for certain conditions. Other research is looking at using the microbiome as a therapeutic target to help patients who survived a trauma or are dealing with anxiety. Many in the research community see the microbiome as a potential tool to address a wide variety of mental and emotional issues.

This is a complicated dance, one that science is only beginning to understand. But there is one thing microbiome researchers know without a doubt: what people eat has an impact—positive or negative—on their microbiome and their mood. The bottom line is keeping things in balance.

The Western Diet & the Microbiome

There is one thing microbiome researchers know without a doubt: what people eat has an impact—positive or negative—on their microbiome and their mood.

The Western diet is high in simple sugars and damaging types of fat. New studies continue to show how these foods dysregulate the microbiome.

It goes without saying that you must stay away from junky, processed foods, which are not only loaded with simple sugars and fats, but also contain a variety of questionable chemicals—dyes, preservatives, flavor enhancers, etc. Even worse, junk foods can have a perilous effect on mood. Consider what happens when you eat a donut. You might feel great for about 15 minutes, but then, you crave another one. And people tend to crave sugary, fatty foods when their mood is low. Trouble is, rather than improving mental balance and stability, this leads to a downward spiral.

The Western diet affects the microbiome in other profound ways. Multiple studies show that junk foods throw the microbiome out of balance, allowing more aggressive, disease-promoting microbes to flourish. This can lead to chronic inflammation, leaky gut, and other health-robbing conditions.

There is one thing microbiome researchers know without a doubt: what people eat has an impact—positive or negative—on their microbiome and their mood.

Gut Microbiome Diet

If you eat a good diet rich in fruits and vegetables, you simply feel better. Healthy fats, like omega-3 fatty acids found in such foods as wild salmon, sardines, walnuts, and chia and flax seeds, have been linked to enhanced learning and memory.

A 2017 study, published in the journal PLOS One, showed that teens and young adults who had better access to fruits and vegetables improved their psychological well-being. These improvements happened fast. Participants showed improved “vitality, flourishing, and motivation” in just two weeks.

Another study, published in the American Journal of Public Health, showed that increased fruit and vegetable consumption was “predictive of increased happiness, life satisfaction, and well-being.”

The important thing to remember is that when you eat, you’re not only feeding yourself, you’re feeding your microbiome.

Which foods are best for your microbiome?

You can actually write your own prescription by choosing different fruits and vegetables for their specific health-promoting effects.

First, be sure to get macro-nutrients (healthy fats, good-quality complex carbohydrates, and clean protein sources) and micronutrients (minerals, trace elements, phytonutrients) in your diet—both are needed for optimal physical and emotional well-being. In the vegetable department, there are some superstars. Kale, broccoli, spinach, beet greens, collards, and other green leafy vegetables are particularly nutrient-dense. That’s not necessarily a secret. But some of these can have a profound impact on the brain. Here’s a closer look:

  1. Spinach, chard, and broccoli are rich in magnesium, which supports relaxation and increases a neurotransmitter called GABA. Greens are also rich in folate and other B vitamins, which are good for stress management.
  2. Yogurt and kefir have good amounts of magnesium and provide a boost to the microbiome
  3. Nuts and seeds, including almonds, sesame, pumpkin, and sunflower seeds, are also good magnesium sources.
  4. For a treat, indulge in dark chocolate, also high in magnesium.
  5. Sea vegetables are high in trace minerals, many of which are not always found in the average diet. They also contain vitamin B and amino acid
  6. Kale, broccoli, cauliflower, cabbage, and other cruciferous vegetables are rich in mood-supporting compounds.
  7. Cabbage, broccoli, and asparagus contain tryptophan, which supports relaxation.
  8. Avocados are rich in healthy fats, protein, vitamin B, folate, and tryptophan. They support both healthy mood and relaxation.

Best Supplements for Microbiome Health & Mood

Certain supplements support a strong microbiome, as well as help with mood. Here are my top suggestions:

1. Probiotics & Prebiotics

Probiotics, found naturally in yogurt and many fermented foods, populate the gut with healthy flora. It’s unclear, though, whether a few million microbes from a serving of yogurt have any impact on restoring gut balance. Taking a probiotic supplement on a regular basis ensures that your gut is getting a steady supply of healthy bacteria. Use a formula that includes prebiotics, or add a separate prebiotic supplement in addition to a probiotic—prebiotics provide food for probiotics.


When normal levels of GABA (gamma-aminobutyric acid) are present in the brain, you feel calm and at ease, and you sleep well. When you don’t have enough, stress, anxiety, nervousness, irritability, and insomnia take over. One study showed the gut bacteria Lactobacillus rhamnosus positively altered GABA activity in the brains of test animals, and also improved their stress response. In addition to GABA supplements, you can also increase GABA by taking the amino acid L-theanine (found in small amounts in green tea), inositol, magnesium, and chamomile.

3. L-tryptophan

Tryptophan is an amino acid that is used by the brain and converted into serotonin, a neurotransmitter that governs feelings of depression, anxiety, and sleep. More than 90 percent of your serotonin is found in the gastrointestinal tract. People with impulsive or aggressive personalities may benefit the most from tryptophan. In studies of adults who are self-described as “quarrelsome,” 1,000 mg of tryptophan three times a day produced increases in measures of agreeable behaviors. Tryptophan can cause drowsiness.

4. Vitamin D

Numerous studies link low levels of vitamin D to depression. Research shows that vitamin D impacts gut health too. A study published in the European Journal of Nutrition showed that high-dose vitamin D supplementation resulted in a healthier balance of gut bacteria. The researchers concluded that the study “supports the beneficial effect of a high-dose vitamin D3 supplementation on the human gut microbiome.” Get your vitamin D level tested by your doctor. Typical dosages vary from 1,000 IU to 5,000 IU, but you may need more depending on your blood test results.

5. Zinc

Is a key nutrient for hormone regulation and immune health. It can also support neurological function. Recommended dosages range from 15–50 mg daily.

Magnolia & Other Mood-Lifting Herbs

Several herbs can help reduce depression and anxiety symptoms related to stress, including passionflower, lemon balm, valerian, and lavender.

Several herbs can help reduce depression and anxiety symptoms related to stress, including passionflower, lemon balm, valerian, and lavender. I am particularly fond of honokiol, a compound from magnolia bark (Magnolia officinalis), used for centuries in traditional Chinese medicine to promote relaxation and healthy digestion. Honokiol has been shown to cross the blood-brain barrier for direct effects on the central nervous system.

Cinnamon is good for the tummy, soothing discomfort and improving digestion. It also has a positive impact on blood sugar, helping prevent the peaks and valleys that are so bad for our mental state.

For more on the gut-brain connection, read more here: