Gut Health: How What You Eat Influences Your Mood

My contention is that…

  • when you are in a bad mood, you eat unhealthy food
  • unhealthy food puts you in a bad mood
  • healthy food keeps your gut healthy
  • a healthy gut brightens your mood

A man is putting his hands on his stomach

Do you know the experiment with the swimming mouse? It demonstrates that unhealthy food negatively impacts your mood. When the quality of your food declines, the first thing to go is your good mood – long before you see the effects in your body. This is what Julia Ross argues in her book The Mood Cure – The 4-Step Program to Take Charge of Your Emotions – Today.

Digestion and mood

Back to the mouse… It concerns an experiment used in the field of motivation and depression research called the swim test: A mouse is placed in a small tank of water. It swims vigorously, trying to find a way to escape. The mouse wants to survive, that is its primal instinct, so it continues to struggle. But this is not true for mice exhibiting signs of depression — these mice struggle half-heartedly until they finally give up and float. In the experiment described in the book, Irish researchers gave the mice probiotic bacteria, which have been shown to have beneficial effects on gut health, before placing them in the tank. These bacteria-fed mice swam much longer, more powerfully and with less adrenaline in their blood than those without the bacteria. The bacteria used in the experiment were psychoactive bacteria, which are said to produce mood-boosting substances. This shows that our brain and our digestive tract are closely connected.

Therefore, if we eat clean and feed our gut healthy foods, this can have a positive influence on our brain and increase our vitality. As Hippocrates said, “All disease begins in the gut.” If our gut is healthy, this puts us in a better mood and relieves symptoms of depression. Eating unhealthy foods, like trans fats, can affect our mood and contribute to depression. Trans fats are found in natural foods like meat or milk and industrially produced foods like baked goods (cookies, cakes), convenience foods, fries, chips, fast food, etc.

In her book Gut, Giulia Enders suggests that maybe it is your gut that belongs on the therapist’s couch and not your head. How we eat influences, among other things, whether we go through life in a good or bad mood. Researchers at the University of Oxford wanted to find out if the inmates of a prison near London were more peaceful if they ate a healthier diet. Normally, the prisoners’ meal plan consisted mainly of bread, fries and sweets. In the experiment, the inmates ate the same food but in addition received a pill with vitamins, minerals and fatty acids. Within the short span of five months, the test subjects committed 37% fewer criminal acts than their fellow prisoners who did not receive the pill.

A bowl of walnuts on a wooden table

A few vitamins and minerals are the secret to a more tranquil life? In her book The Mood Cure, Julia Ross talks about the following “good mood foods”:

  • Fish (“Japanese people eat ten times more fish than Americans and suffer from depression ten times less often”), poultry, eggs, seafood, on account of the protein
  • Flaxseed, nuts and fish because of the omega-3 fatty acids
  • Vegetables – the more vibrant and colorful, the better
  • Carbohydrates from fruit, vegetables, legumes and whole grains

Foods like chicken, tuna, legumes and nuts contain tryptophan, an amino acid. This amino acid is responsible for maintaining the serotonin levels in our brain. If these drop, we get moody and feel depressed. In order for the body to absorb it, tryptophan has to be combined with carbohydrates. This might explain why dieters who completely eliminate carbohydrates may often find themselves in a bad mood.

Omega-3 fatty acids also improve your mood. Joseph Hibbeln, a psychiatrist from the USA, examined the blood samples of 800 people who committed suicide. All 800 showed a significantly low level of omega-3 fatty acids in their blood.

Two slices of avocado on bread

Healthy gut flora

You can do your gut some good by fasting regularly. The neurologist David Perlmutter recommends fasting for 24-72 hours every season. You can also make your gut bacteria extra happy by incorporating the following superfoods into your diet: pickles, sauerkraut, yogurt, salmon, herring, avocado, coconut oil, turmeric, mustard. Wine, coffee and chocolate (in moderation) promote healthy gut flora as well.

Mood and digestion

Not only our gut and its contents can positively or negatively affect our mood, but our moods can also influence our digestive tract. When you are anxious and stressed, you can quickly develop a nervous stomach and diarrhea or your digestive system might shut down and stop absorbing the food you eat.

The exact relationship between nutrition, gut flora and mind has yet to be determined, but it is an interesting topic and one I will continue to follow in future.

One last tip: if you have been in a funk for a while, you might be suffering from a vitamin D deficiency. You should have your blood levels checked by a doctor to assure that they are within the normal range.

Bye for now,



Vera Schwaiger Vera studied dietetics & psychotherapy. She lives her life according to what Einstein once said: "Life is like riding a bicycle. To keep your balance, you must keep moving." View all posts by Vera Schwaiger