Is Gut-Lag Real? Here's The Science of How Travel Affects Your Gut
Say hello to the holiday season, which, let’s be honest, basically started the moment Halloween ended. And as the first notes of holiday music rang out, you took your cue to dust off the tried-and-true pumpkin pie recipe, grab the cinnamon and cloves off the spice rack, and ascend the rickety ladder to get the decorations out of the attic.
It’s a wonderful time of year, but it’s also a season that’s heavy on travel which, in my opinion, can leave a person feeling more hungover than they do on Thanksgiving Eve. Not only is jet lag a possibility, but gut-lag—or that heavy, slow feeling in your gut—is as well.
But what if we could avoid that feeling altogether? Can we manipulate our gut microbes to minimize the damage done by changing time zones (or simply hopping on a plane and, therefore, altering our everyday routine)? Let’s get into it.
Why travel causes jet-lag
Let's start with circadian biology 101. I know, science—boring, right? But believe it or not if you want to understand jet lag, you’ll want to first understand a bit about circadian biology. That’s because it’s the critical piece that informs our understanding of why daylight saving time can be shockingly debilitating. Let’s start at the beginning, but with the abbreviated version.
Mother Earth has always had a daily, reproducible pattern of light and dark on a time cycle. These fluctuations of light are caused by the planet’s rotation around its own axis, and resultant exposure to light from the sun.
When you consider that this pattern of light and darkness has been in existence since day one, it probably won’t surprise you that life on Earth developed a biological clock adapted to this pattern. But what is surprising is that all life on Earth has a biological clock—not just humans, mammals, or even plants. The microscopic life that we can’t see like bacteria, fungi, and archaea all have a circadian rhythm too.
This circadian rhythm impacts multiple biological processes. It’s been connected to our metabolism, behavior—even our immune system. For example, two hormones—melatonin and cortisol—are regulated by your brain. These two hormones play a critical role in balancing sleep and wakefulness. As melatonin rises, cortisol falls, and vice versa; it's the classic “opposites attract” situation. What’s interesting, is that light exposure during the day has the ability to alter hormone levels. For example, when the sun goes down our melatonin levels start to rise in preparation for sleep, but we can disrupt this process by exposing ourselves to bright light (hello, smartphones, laptops, and bedroom televisions!).
What happens when the circadian rhythm is out of whack.
You might have already guessed this, but exposure to bright light that disrupts our melatonin levels and sleep-wake cycles is only the tip of the iceberg. For this part of our journey, we’re going to take a trip to the past during a time when jet lag wasn’t a thing. Why? Well, the jet hadn’t been invented yet. I wonder what the first transatlantic passengers thought after they landed in their new locale (and felt ultra-tired).
But the thing is, these concepts extend beyond jet lag. Circadian biology is also critically important to shift workers like nurses, firefighters, police officers, and security personnel. These rescue workers are crucial parts of our society, but, unfortunately, studies have found that disruption of the normal sleep-wake cycle—which is common among these professions—is associated with increased risk of hypertension, hyperlipidemia, obesity, and type 2 diabetes. Shift work is like repeated jet lag without boarding a plane or leaving your locale.
Is gut-lag a real thing?
So what does that have to do with your gut, right? Well, the short answer is that jet lag can also result in gut-lag, which is exactly what it sounds like. But let’s take a deeper dive to understand some of the science behind it first.
Doctors at the well-respected Weizmann Institute of Israel started by following the gut microbiome of mice every six hours and found daily reproducible fluctuations. When the mice were asleep, their gut microbiome showed activation of the genes involved in energy metabolism, DNA repair, and cell growth. When the mice were awake, the gut microbiome showed activation of genes involved in detoxification and environmental sensing. The point being, the gut microbiome was different depending on whether the mice were awake or asleep, and it was adapted to what their bodily needs were. Fascinating, right?
But there’s more: On closer examination, the researchers discovered that it was the regular timing of food intake that determined these fluctuations in the microbiota. When the simulated jet-lag for the mice, they discovered that the alteration of regular feeding patterns caused disruption of these normal fluctuations and unhealthy alteration of the gut microbiota, or dysbiosis. In other words, chronic jet-lag or shift work is damaging to the gut. The pattern seen in the microbes was found to predispose people to weight gain and glucose intolerance. This now explains why obesity, diabetes, and cardiovascular disease have been identified in earlier studies of shift-workers.
So how do I avoid gut-lag?
You’ll want to know this no matter the season, but steering clear of gut-lag seems especially important with holiday travel on the horizon, right?
Here are a few tips to help keep your gut on task:
Adjust your schedule.
Start to adjust your schedule before you leave. Since mealtimes are so important to maintaining normal function, start making shifts in the time you eat during the week prior to leaving for your trip. That way, your gut will be on a schedule by the time you reach your new location.
Support your gut.
Support your gut before, during and after travel with prebiotic and probiotic supplements. I’d recommend a daily prebiotic fiber supplement, which is known to support the healthy microbes and is metabolized to release short-chain fatty acids (SCFAs) that heal the gut and reverse dysbiosis. You can add a high-quality, multi-strain probiotic before bedtime for added protection.
Water fast while traveling. Rather than eating during travel, I recommend hydration and fasting during the trip as a reset so that you can have a “fresh start” when you arrive in your new location.
Bump up the fiber.
Make your first meal in your new location fiber-rich. You want to support your gut microbiome during this transitional period, so opt for a meal that feeds and nourishes the microbes as opposed to fast food with sugars and fats that actually promote dysbiosis and further disrupt them.
Light exercise upon arrival to your new location can help to support the new rhythm for your microbiome. Note: I wouldn’t do this if you’re on the red eye and going to hit the sack immediately. This is more when you arrive and have a day in front of you.
Re-anchor your circadian rhythm upon arrival. That means making sure to expose your eyes to bright light early in the morning. You need to be very intentional in doing this, not just taking a look out the window, but actually spending time outside. On the flip side, make sure to wind down in the evening by avoiding bright lights and consider a melatonin supplement at bedtime.
Dr. Will Bulsiewicz, M.D., MSCI is a gastroenterologist and internationally recognized gut health expert who wants to help you tap into the incredible healing power that lives inside you—your gut microbiota. His medical training involved 16 years at America's elite institutions. He completed a bachelor’s degree from Vanderbilt University, a medical degree from Georgetown University, and a master's in clinical investigation from Northwestern University. Bulsiewicz was also the chief medical resident at Northwestern and the chief gastroenterology fellow at UNC, and received the highest award given by both his residency and fellowship. He also completed an epidemiology fellowship at UNC's prestigious Gillings School of Global Public Health.