Gut Reaction: Neurotransmitters Serotonin, Dopamine, and Gut Health Synergy

Erin Dollison Nitschke
6 min readOct 24, 2023

The gut, aside from its primary role in absorption, blood sugar regulation, and nutrient distribution, also wields influence over our hormone and neurotransmitter regulation. Among the key hormones in this intricate interplay are serotonin and dopamine. While you might typically associate the gut with “food,” emerging research suggests that these chemicals when imbalanced, can exert a profound impact on our emotional states, revealing a more intricate connection between digestion and mood than previously believed.

This opens the door for personal trainers with a deeper understanding of fitness nutrition to coach their clients in more than just fitness, but in emotional health and wellness as it relates to their diet.

The Complexity of Nutritional Impact

Undoubtedly, the significance of your gut in determining your overall health cannot be overstated. We’ve recently featured articles that delve into the realm of gut health, covering topics ranging from the advantages of adopting the Mediterranean Diet to the transformative potential of fermented foods in bolstering this vital component of our well-being.

If, over time, you find that your client’s fitness and nutrition goals aren’t progressing as desired, it might be worthwhile to encourage them to engage in a deeper investigation into their unique gut health and the indicators that may suggest the presence of an issue, namely how mood-influencing neurotransmitters might be affected by what we eat or don’t eat.

The Roles of the Neurotransmitters/Hormones Serotonin and Dopamine

Serotonin, often referred to as the “feel-good” neurotransmitter, plays a multifaceted role in the body and is primarily associated with regulating mood, emotion, and a wide range of physiological functions. Here are some key aspects of the role of serotonin:

  1. hormone
  2. Mood Regulation: Serotonin is perhaps best known for its role in regulating mood and emotional well-being. It helps to maintain a stable and positive emotional state, contributing to feelings of happiness, contentment, and overall emotional balance. Low serotonin levels are often linked to mood disorders such as depression and anxiety.
  3. Appetite and Satiety: Serotonin influences appetite and satiety, contributing to feelings of fullness and reducing food cravings. This can have an impact on body weight and eating behavior.
  4. Sleep Regulation: Serotonin is involved in regulating sleep patterns. It helps control the sleep-wake cycle and promotes restful sleep. Imbalances in serotonin levels can lead to sleep disturbances, such as insomnia.
  5. Aggression and Impulsivity: Adequate serotonin levels help to inhibit aggressive and impulsive behaviors. Low serotonin levels have been associated with increased aggression and impulsive actions.
  6. Fear and Anxiety: Serotonin is involved in the modulation of fear responses and anxiety levels. Higher serotonin levels can help reduce feelings of fear and anxiety, while low levels may contribute to heightened anxiety.
  7. Overall Well-Being: Beyond its specific roles, serotonin is also thought to contribute to a general sense of well-being and satisfaction with life. Adequate serotonin levels are associated with an improved overall quality of life.
  8. Gastrointestinal Function: Serotonin is found not only in the brain but also in the gastrointestinal (GI) tract. In the gut, it regulates various GI functions, including peristalsis (intestinal contractions), secretion of digestive juices, and overall gut health. This gut-brain connection highlights the role of serotonin in the enteric nervous system.

It’s important to note that serotonin’s effects are complex and interconnected with other neurotransmitters and hormones in the body. Imbalances in serotonin levels can have a significant impact on mental and physical health, and they are often a target for therapeutic interventions, such as medications used to treat mood disorders like depression and anxiety. Additionally, lifestyle factors such as diet, exercise, and exposure to natural light can influence serotonin production and function in the body.

Dopamine is a crucial neurotransmitter in the brain that plays a multifaceted role in regulating a wide range of physiological and psychological functions. Its role is diverse and complex, influencing various aspects of behavior, cognition, and bodily functions. Here are the key roles of dopamine:

  1. Reward and Pleasure: Dopamine is often associated with the brain’s reward system. It plays a central role in the experience of pleasure and reinforcement of rewarding behaviors. When you engage in activities that are pleasurable or satisfying, such as eating, exercising, or receiving praise, your brain releases dopamine, reinforcing those behaviors and motivating you to repeat them.
  2. Motivation and Goal-Oriented Behavior: Dopamine is a key player in motivation. It helps drive goal-oriented behavior by promoting the pursuit of rewards or positive outcomes. When dopamine levels are balanced, it encourages you to work towards achieving your goals, whether they are related to work, relationships, or personal aspirations.
  3. Learning and Memory: Dopamine is essential for learning and memory processes. It helps you associate actions with outcomes, facilitating the formation of memories related to rewarding or significant experiences. This association between dopamine and memory is crucial for adaptive learning.
  4. Movement Control: In the motor system, dopamine plays a critical role in controlling and coordinating movement. A deficiency of dopamine in certain parts of the brain is associated with movement disorders such as Parkinson’s disease, which can result in tremors, rigidity, and difficulty with fine motor skills.
  5. Mood Regulation: Dopamine also has an impact on mood regulation. While serotonin is often associated with mood stability, dopamine can influence mood as well. Imbalances in dopamine levels have been linked to mood disorders, including depression and bipolar disorder.
  6. Attention and Focus: Dopamine plays a role in attention and concentration. It helps you stay alert, focused, and engaged in tasks. Medications that affect dopamine levels are sometimes used to treat attention-related disorders like attention deficit hyperactivity disorder (ADHD).
  7. Pleasure and Addiction: Dopamine is involved in the brain’s response to pleasurable stimuli, including substances like drugs, alcohol, and nicotine. When these substances are abused, they can lead to excessive dopamine release, contributing to addiction and dependency.
  8. Stress Response: Dopamine also plays a role in the body’s response to stress. It can influence how the brain and body react to stressful situations and help prepare for the “fight or flight” response.

It’s important to note that the roles of dopamine are interconnected, and its regulation is a complex process involving various brain regions and pathways. Imbalances in dopamine levels can have profound effects on behavior, mental health, and overall well-being. Drugs that target the dopamine system are used in the treatment of conditions like schizophrenia, depression, and Parkinson’s disease to help restore balance and alleviate symptoms.

A disruption in the equilibrium of these crucial hormones can undoubtedly hinder your client’s progress and training. Detecting these imbalances can be challenging, but as a coach, there are telltale signs to watch out for. It’s important to clarify that these signs aren’t an automatic diagnosis but rather potential indicators that might warrant consideration and intervention to rectify any imbalances.

Practical Application Example

Jane attends her training session, her third this week. She appears fatigued, moving with less vigor than usual, and expressing a sense of difficulty. In this moment, inquire about her recent sleep quality, hydration habits, and nutritional choices over the past few days or weeks. What is her motivation level to pursue the goals she set in the beginning? Listen attentively to her responses and continuously rely on open-ended questions and motivational interviewing techniques.

Given the central role of nutrition in gut health and hormone regulation, it’s often necessary to temporarily shift the focus away from the workout to discuss nutrition. Emphasize the importance of a balanced diet and elucidate why it matters.

Inquire as to how many “gut-friendly” foods are regularly present in her dietary selections. These include:

  • legumes, like black beans and chickpeas
  • whole grains, like oats and quinoa
  • vegetables, like broccoli and asparagus
  • nuts, like almonds and pistachios
  • fruits, like apples and peaches

Salmon, rich in omega-3 fatty acids, also contributes positively to maintaining hormone balance. For therapeutic purposes, suggest incorporating yogurt and fermented foods like sauerkraut and kefir into her daily intake. These are just a few examples of items your client can include in her diet, as they have demonstrated favorable outcomes in promoting gut health and hormone equilibrium.

While there’s more to explore regarding the specific mechanisms and benefits of these foods, reinforcing their helpfulness can influence your client to incorporate them into her weekly meals. The gut is a remarkable system that thrives with consistent care. By tending to it attentively, success in achieving her fitness and wellness goals is bound to follow suit.

For more gut health information, check out these sources.

Healthline Gut Health

Johns Hopkins

The Gut Microbiome — Harvard



Erin Dollison Nitschke

Passionate college educator, writer, and health and fitness professional. I am an NFPT-CPT, NSCA-CPT, ACE Fitness Nutrition Specialist, ACE Health Coach, & Pn1.