Serotonin and digestion have gotten a lot of attention in recent years, and with good reason! Serotonin (the feel-good hormone) is much more than just a neurotransmitter in the brain that regulates your mood, happiness, sex, and feeding. Serotonin and digestion work hand in hand, and our entire well-being is centered around the gut!
We now know that the digestive tract is the root of our overall health.
It’s well-known in science that 90% of serotonin is made in the gut (not the brain, though it’s definitely found there also!). It was previously thought that 90-95% of the gut was stimulated by signals from the brain, but we now know that the reverse is true: the signals are carried from the gut to the brain. Usually in the form of abdominal pain, nausea, and vomiting, like “Ugh, I’m not eating that again!”.
Serotonin works by causing intestinal contractions which stimulate digestion, so you can see why serotonin and digestion are so crucial to healthy living. The gut has its own autonomic nervous system, meaning it doesn’t rely on the brain for signaling. If the two systems were separated, the gut could function completely on its own! Serotonin in the gut signals pain, nausea, and other digestive issues which is why antidepressants can cause side effects such as nausea and vomiting. As antidepressants block the degradation of serotonin in the brain, they do so in the gut as well.
Low levels of serotonin in the gut have been linked to Irritable Bowel Syndrome, or IBS. When there isn’t enough serotonin in the intestinal tract, irregularity is the response our bodies give. Diarrhea, constipation, bloating, and abdominal cramping are just some of the symptoms. Decreased gut serotonin can also make a person more prone to fibromyalgia, disrupt sleep patterns, and is associated with anxiety and depression.
Researchers have also been looking into how the gut microbiome affects weight and obesity issues, and why some people eat more than others. Our digestive tract is an entire thriving ecosystem, completely unique to each person. Those with a healthy gut microbiome (a diverse amount of bacteria) are more likely to maintain a healthy weight and have less tendency toward chronic diseases. One theory is that if one type of gut bacteria is more predominant than the others, it can lead to changes in the hormones insulin and leptin, which affect our appetite and metabolism.
Serotonin is found in high concentrations in foods like pistachios, walnuts, plantains, kiwi fruit, pineapples, bananas, and tomatoes. But eating these foods isn’t enough! The body also relies on amino acids like tryptophan to boost gut serotonin levels. We have to be cautious, though, because most tryptophan is found in complex carbohydrates. So it totally makes sense why we might crave comfort foods when we’re feeling depressed – higher serotonin!
It’s not just tryptophan that’s a key player in the regulation of serotonin. B-vitamins, like thiamine (B1), and folic acid also play crucial roles in how our bodies utilize serotonin. For the full serotonin benefit, be sure to consume adequate amounts of foods like turkey, eggs, fish, milk, yogurt, and beans. Supplementing with thiamine and folic acid can also drastically improve your mood because of their overall actions on serotonin!
Our mood affects our nutrition choices just as much as the opposite is true. Research shows that dieters tend to feel depressed only two weeks into a diet (which is why dieting does not and will not ever work!), leading to lower gut serotonin levels (via a reduction in carbohydrates usually). Women tend to be more sensitive to this. When a woman starts a diet and reduces her carbohydrate intake, her serotonin levels drop, causing her to crave carbohydrates. She then consumes carbohydrates (no, this is not because of a lack of willpower), feels guilty for having done so, and the yo-yo dieting cycle repeats itself. Now you see part of the reason women are so prone to eating disorders.
So what do we do about it all? How do we modulate our serotonin and digestion for optimal health?
We eat well-balanced meals, rich in veggies and fiber! Try these tips:
- Eat until you’re full, but not over-stuffed. Eating three well-balanced meals a day will help keep the gut functioning properly and blood sugar stable.
- Eat gut-friendly foods: vegetables (a whole variety!), fruits, fish, lean meats, whole grains and complex carbohydrates. Cut back on the processed foods, fast food, refined sugars and carbohydrates; reduce your intake of alcohol and caffeine.
- Ditch the food intolerances. If dairy causes gas and bloating, try eliminating it and seeing how you feel. If wheat causes fatigue and joint pain, get rid of it for a few weeks.
- Get rid of your acid reducer and learn to eat right! My mom recently stopped her Prilosec after being on it for years. We know that a healthy gut requires a good amount of calcium and B-Vitamins; PPIs like Prilosec (omeprazole) inhibit these long-term.
Now you’ve got the link between serotonin and digestion! For a huge mood and gut boost, go try these recipes!
- Butternut Squash & Wild Rice Salad with Apples, Kale, and Maple Glazed Pecans
- Slow Cooker Lentil Stew with Chicken Sausage & Kale
- One-Pan Chicken & Mushroom Farro
Case-Lo, C. (2016, March 21). IBS and Serotonin: The Brain-Stomach Link. Retrieved December 27, 2017, from https://www.healthline.com/health/irritable-bowel-syndrome/serotonin-effects#serotonin-in-your-gut-and-brain
Moore, A. (2012, April 15). What Your Gut’s Telling You: Why Your Digestion Holds the Key to Your Health. Retrieved December 26, 2017, from http://www.telegraph.co.uk/women/womens-health/9197756/What-your-guts-telling-you-why-your-digestion-holds-the-key-to-your-health.html
Wilcox, C. (2009, June 24). Understanding Our Bodies: Serotonin, The Connection Between Food and Mood. Retrieved December 27, 2017, from http://nutritionwonderland.com/2009/06/understanding-bodies-serotonin-connection-between-food-and-mood/