Why Gut Health is Critical for Optimal Performance and Wellness
The Gut-Brain Connection
There is a tight connection between our gut health and brain functioning, metabolic health, psychological health, performance, and overall wellness. Recent research shows that the gut microbiome (bacteria, fungi, protozoa, viruses) plays an essential role in the central nervous system via its effects on digestion, immune functioning, systemic inflammation, the hypothalamic-pituitary axis, and many other aspects of health.
The vast majority of the research on the microbiome has been conducted with animals (typically mice), but we now have a few small studies in human subjects. The available data so far appear to show that an unhealthy gut microbiome is associated with depression, anxiety, and various other mood disorders. Research also suggests that gut microbiota interacts with the reward system of the brain as it relates to the individual pursuit and use of food, drugs, and pleasure.
Our 2020 Study
In 2020 we published a study in the Journal of Affective Disorders with 111 adults who were inpatients in a psychiatric hospital to examine the gut microbiome among people with severe mental illnesses.
Patients reported their clinical symptoms through a battery of self-report questionnaires related to psychiatric symptom and functioning, and then provided fecal samples shortly after hospital admission. We worked with a team of microbiologists to sequence the DNA of the bacteria and identify different types of bacteria.
Analyses indicated that the severity of depression and anxiety at the time of hospital admission was negatively associated with gut bacterial richness and diversity. We also identified patterns of gut bacteria associated with depression and anxiety treatment resistance by the time of discharge from the hospital. In other words, we were able to identify patients who did not benefit from treatment, based solely on a fecal sample!
Much more research is needed before we will be able to fully understand the gut and its role in health and behavior, its multiple roles within our body, and how to best care for it – but we know it is vital for our well-being.
The Microbiome
Our gut microbiome weighs up to five pounds, and has 200 times the number of genes found in the human genome. It is symbiotic, not parasitic, to us. We need our gut microbes and they need us. We survive and thrive together, and therefore it is imperative that we take good care of it. A healthy gut is an essential component of health, performance, and general wellness.
So, how do we best take care of this mysterious universe of organisms that live within us?
Lifestyle Habits to Promote Gut Health
- Eat a healthy diet with plenty of fiber, lean protein, fats, and water.
- Pre-biotics, plant fibers that facilitate the growth of healthy bacteria, such as apples, bananas, barley, berries, cocoa, flaxseed, garlic, oats, onions, tomatoes, soybeans, and wheat.
- Pro-biotics, such as yogurt, kefir, vinegar with active cultures, fermented pickles and sauerkraut, kimchi, etc. You can even take dietary supplements.
- Eliminate or minimize consumption of processed food, junk food, fast food, soda, and added sugar.
- Consider an intermittent fasting or time-restricted feeding approach.
- Consider whether you have food sensitivities or allergies that might benefit from a special diet (e.g., low FODMAP).
- Exercise on a regular basis – especially strength training.
- Pursue high-quality sleep, and plenty of it.
- Eliminate or minimize alcohol use.
- Regularly engage in meditation, yoga, prayer, or other relaxing activities.
- Consider past exposures to toxic chemicals, heavy metals, excessive smoke, etc., that may require medical consultation.
- Spend time outdoors.
The Science of Gut Health
Our scientific understanding of the gut microbiota is still in very early stages, and it is true that most human studies to date only examine the strength of the association between psychological functioning and gut health. From Psychology 101 we are reminded that “correlation is not causation.” Nevertheless, with what we know now and what we can hypothesize, there is every reason to take good care of your gut health – and absolutely no reason not to.
The best part is that whatever is good for your gut is also good for your weight, heart, lungs, muscles, skeletal system, skin, brain, cognitive functioning, wellness, and functional performance – and I mean performance in literally every important area of personal and professional life.
My Personal Dietary Protocol
I take a daily intermittent fasting approach, with a feeding window of about 6-9 hours most days. My first meal of the day is a smoothie made with a varied mixture of frozen fruit (e.g., blueberries, raspberries, blackberries, strawberries, cherries, pineapple), fresh fruits (bananas, apples, exotics), vegetables (carrots, spinach), dairy (yogurt, kefir), avocado, MCT or olive oil, and a blend of nuts (walnuts, pecans), seeds (flax, chia, hemp, pumpkin, sesame, sunflower), cacao nibs, a variety of so-called “superfood” powders (e.g., ginger, beetroot, cinnamon, mushroom extracts, noni, maca, acai), shredded coconut, oatmeal, and unsweetened protein powder.
I prep a week’s worth of this dry blend of nuts/seeds/powders/oatmeal every weekend using 2-cup plastic containers. This means I can blend and eat my first meal of the day in about 15 minutes. My preference for protein powders is unsweetened pea powder, collagen powder (with multiple peptides), and grass-fed beef/egg white powder (e.g., PaleoPro). (Note: I rarely use whey powder because of the effect it has on my gut functioning.)
For dinner, I usually eat beef or seafood with a salad and/or a large serving of mixed vegetables (baked, stewed, or stir-fried). By now you’re probably wondering where I stand on carbs like bread, pasta, rice. The answer is that I do eat them… in moderation.
Typically, I have a half-cup of oatmeal at my first meal and 1-2 pieces of bread at my second meal. I bake all of my own bread using my own homemade sourdough starter (which is so much easier than we have all been led to believe) and organically grown whole-grain ancient and heirloom wheats that have been stone-milled (e.g., Janie’s Mill). So, my homemade bread has lots of healthy fiber, nutrients, and fermented dough (which is filled with lactobacilli, a healthy bacteria).
If my dietary protocol sounds a little hard or too time-consuming, it's actually not. It is easy once you’ve put in a few reps and it is extremely time-efficient. If it sounds too earthy, nutty, crunchy for you, all I can say is this: Try it for two weeks. You are likely to feel so much better that you never return to your old dietary habits.
You don’t have to be perfect – I’m certainly not – and even small changes can be transformative. Bon appetit!
Chris Frueh, PhD is a professor of psychology at the University of Hawaii. He has over thirty years of professional experience working with military veterans, servicemembers, special operators, private defense contractors, and firefighters; and has conducted clinical trials, epidemiology, historical, and neuroscience research. He has co-authored over 300 scientific publications. He was previously a professor of psychiatry at Medical University of South Carolina and Baylor College of Medicine. He devotes effort to the SEAL Future Foundation, Boulder Crest Foundation, Military Special Operations Family Collaborative, The Mission Within, VETS, Inc., Special Operations Association of America, and to the military special operations and responder communities in general.