"What does your gut say? Well, a lot. You can’t have a conversation about digestion, mood, immunity, or hormones without the gut entering the chat. #GutTok even has its own hashtag on TikTok, where you can find the latest viral gut-related trends and hacks. Considering the ecosystem of trillions of microorganisms that reside in it (linked to everything from bloating to chronic diseases) trusting your gut makes perfect sense. In the Netflix documentary Hack Your Health: The Secrets of Your Gut, doctors and scientists explore how the gut works and why people with similar diets can differ in weight and health. Consider it a tell-all film of the gut, and it totally blew my mind. Ahead are my main takeaways from the film.
1. Diet diversity is the most important factor for gut health
Having the same kale salad every day is not as healthy as we may have thought. “The more diversity you consume, the more rich your microbiome will be, and the more species of bacteria that will be present inside your gut,” explained Jack Gilbert, a microbial ecologist at the University of California San Diego. Microbial diversity in the gut is associated with better gut health. Consuming a variety of whole foods, including protein, fats, and carbohydrates, ensures you obtain a wide range of nutrients necessary for overall health and optimal gut function. “It’s not about restricting things,” continued Tim Spector, a genetic epidemiologist at King’s College London. “It’s about enlarging your world of foods that are possible for you to eat.”
2. Every person’s microbiome is unique and made up of “memories”
What you eat, where you live, where you travel, your experiences as a child, and even whether you exercise, stress, or have pets, all make up your gut microbiome, meaning just like each of us has a unique genetic makeup, not one gut microbiome is alike. Giulia Enders, a medical doctor from Germany, likes to think of the gut microbiome as a collection of microbial memories. “For us to understand our differences, we have to first look at where our microbes come from,” she conveyed. As soon as we’re born, we begin to acquire microbes, or bacteria, that contribute to each of our distinct microbiomes. Once we’re exposed to modernization, including medical practices, changes to our environment, the Western diet (read: eating more processed foods), and antibiotics, our microbiomes become industrialized and less diverse.
Because everybody has a unique microbiome, the way we process the same foods will look different. “When we put these calorie labels on boxes, we think, ‘OK, this is the amount of energy that we will all extract if we ate that same food,'” said Eran Segal, a computational biologist at the Weizmann Institute of Science. “But, of course, that is not true.” As explained in the documentary, if you were to give an apple to three different people, each individual would respond differently to the same apple and extract different nutrients and amounts of energy from it. Scientists can predict which foods are best for each person by studying one’s microbiome.
3. The gut is the second brain
There’s our brain that controls thought, memory, emotion, touch, motor skills, vision, breathing, temperature, hunger, and every process that regulates our body. Then there’s our second brain in the walls of the digestive system—the enteric nervous system (ENS)—that links digestion, mood, health, and even the way you think. “Our gut affects our whole body,” said John Cryan, a neuroscientist at University College Cork. “It can even affect certain conditions in the brain… The gut really is the second brain.” Known as the gut-brain axis, the two-way street of communication between the gut and brain links the emotional and cognitive centers of the brain with intestinal functions. And it may be what allows us to enjoy the food we eat and tells us what and when to eat, Cryan shared. “It’s not only that the microbes could affect your brain, but it’s the food you take that can affect the microbes that can affect your brain.”
The gut microbiome creates 95 percent of the neurotransmitter serotonin, which regulates anxiety and is essential for relaxation, sleep, and concentration. The bottom line is when your gut health is poor (read: your gut microbiome is imbalanced), your mood, immune health, and sleep quality, just to name a few, pay the price.
4. Microbes can be more telling than our DNA
According to the documentary, 99 percent of the genes in and on our body are from microbes. They help with digesting food, reducing inflammation, supporting the immune system, shaping hormones, and signaling whether we are hungry or full. “We, oftentimes, believe that our human genes determine our health, but now we know that the microbiome is very central to being obese, being depressed, having allergies, or how stressed or relaxed you feel,” Enders said.
A 2013 study by the National Institute of Health examined the role gut bacteria plays in obesity. Researchers took gut bacteria from four sets of human twins in which one of each pair was lean and one was obese and introduced the microbes into mice. The results? The mice given bacteria from a lean twin stayed the same, whereas those given bacteria from an obese twin quickly gained weight, even though all the mice ate about the same amount of food. Translation: Lean and obese humans have clear differences in their gut microbial communities and those of obese people are less diverse, which can explain why some people experience various weights, even on similar diets or fitness routines.
Gilbert shared that researchers have found that people with certain depression-like symptoms are missing bacteria in their gut that produce chemicals that shape brain chemistry and change how you feel. “When you give a normal mouse microbes from a healthy person and allow them to explore, they’ll want to see bright areas and be generally inquisitive,” Cryan described. “Whereas if you give them the microbes from a depressed individual, they’ll huddle into dark areas, and they will develop stress, anxiety, and depression.” Talk about food for thought.
5. We can change our microbes
While we may not be able to change our genes, Spector affirmed we can alter our bacteria through simple changes to our diet and lifestyle. “What you eat today will impact your microbiome tomorrow, within 24 hours,” said Annie Gupta, a neuropsychologist at UCLA. She recommends ABC: always be counting. Not calories but rather the number of fruits and vegetables you’re eating. The goal? 20-30 different fruits and vegetables each week.
There’s no question certain foods can actively promote the growth of beneficial bacteria. Justin Sonnenburg, a microbiologist at Stanford, suggested thinking about what the generations before us ate: vegetables, fruits, nuts, beans, and fermented foods (AKA the OG probiotics). “You can be vegan, non-vegan,” Spector stated. “Doesn’t matter. The key is getting the diversity of plants in all their forms, as many as you can on your plate to feed your microbes.”
