March: Sleep Awareness Month – The Gut-Sleep Connection You Need to Know
Written by: Vincent Pedre M.D. | March 19, 2024 | Time to read 13 min
March is Sleep Awareness Month, and it’s the perfect time to talk about something that doesn’t get nearly enough attention— the link between gut health and sleep. If you’ve ever gone to bed with a full stomach and tossed and turned all night or woken up at 2 or 3 a.m. with acid reflux, you’ve already felt firsthand how your gut impacts your sleep quality.
But did you know your gut produces 400 times more melatonin than your brain? And while this melatonin isn’t used for sleep, it plays a crucial role in gut motility, antioxidant protection, and even anti-cancer defenses ⸺ all things you need for better sleep.
As a gut doctor for 20 years, I’ve seen a ton of sleeplessness in my practice. It’s the one thing that can take a perfectly well-adjusted person’s life and turn it upside down. When sleep goes, it starts a downward spiral of health consequences that can affect the gut, the brain, mood, mental health, and the gut-brain axis.
Let’s dive into how your gut and sleep are connected, why eating at the right times is just as important as what you eat, and how fixing your gut can lead to deep, restorative sleep.
The Hidden Link Between Gut Health and Sleep
You probably already know that melatonin is the hormone responsible for making you feel sleepy. It’s released by the brain’s pineal gland in response to darkness, helping to regulate your circadian rhythm —your body's internal 24-hour clock.
But it’s not the only key player here. Another important neurotransmitter ⸺ serotonin ⸺ acts as aprecursor to melatonin. In the brain’s pineal gland, serotonin is converted into melatonin through a biochemical process.
Your gut is also responsible for producing about 90% of your serotonin, the neurotransmitter that stabilizes mood and is a precursor to melatonin.
This is where it gets interesting, because you’ve probably heard the wrong information in dozens of interviews, and I want to set the record straight.
Despite being the same molecule, the serotonin in your gut does not directly mix with the serotonin in your brain – they are kept separate.
And there’s more…
The reason gut-derived serotonin (melatonin’s precursor) doesn’t reach the brain is the blood-brain barrier (BBB) – a protective lining of cells around the brain’s blood vessels that strictly controls what enters the brain. Serotonin itself cannot cross the blood-brain barrier, so serotonin made in the intestines or by gut microbes cannot enter the brain’s circulation.
The serotonin used by the pineal is sourced locally (from the brain’s tryptophan pool), not delivered from the gut or bloodstream. The brain must synthesize its own. It does so using a building-block molecule called tryptophan (an essential amino acid obtained from our diet), which can cross the blood-brain barrier.
Here’s the gut-sleep twist (plus the gut serotonin dilemma):
The gut produces and regulates melatonin independently from the brain.
The gut produces and regulates serotonin independently from the brain.
This gut-produced melatonin doesn’t put you to sleep —instead, it helps regulate digestion, gut movement (motility), and immune function.
This gut-produced serotonin doesn’t help with your mood ⸺instead, it also helps regulate gut motility and vagal tone.
If your gut is out of balance due to inflammation, poor diet, or dysbiosis (imbalanced gut bacteria), it can affect how well your body produces and responds to melatonin, leading to disrupted sleep patterns.
In summary, the brain (including the pineal gland) cannot “borrow” serotonin or melatonin from the rest of the body. It must import tryptophan and manufacture whatever serotonin and melatonin it needs locally. This separation ensures that peripheral serotonin (for digestion, blood clotting, etc.) doesn’t accidentally overstimulate the brain, and vice versa.
Tryptophan (precursor to both serotonin and melatonin) from food uses a special transporter to cross the blood-brain barrier, and it has to compete with other amino acids for uptake. In a high-protein meal, plenty of other amino acids are present, so only a limited amount of tryptophan may get into the brain
Interestingly, eating carbohydrates can help more tryptophan reach the brain. Carbs trigger insulin release, which causes many amino acids (except tryptophan) to be absorbed into the body’s tissues, leaving tryptophan with less competition in the blood. This is why a carbohydrate-rich snack (like a bit of fruit or bread) might sometimes make people feel relaxed or sleepy – it may boost tryptophan’s entry to the brain, and thereby serotonin synthesis.
But… Melatonin isn’t just for sleep —it’s also the body’smost powerful intracellular antioxidant, protecting cells from damage and reducing inflammation. This is why melatonin is actually produced by every cell in our bodies.
💡 Key takeaway: A healthy gut is essential for regulating the hormones that control your sleep cycle. If your gut is inflamed or imbalanced, your sleep will suffer —no matter how many sleep supplements you take. On the other hand, a well-functioning gut doesn’t just improve sleep; it also supports overall health, longevity, and even cancer prevention. And eating protein with a complex carb, like sweet potatoes, can help get more tryptophan into the brain to make more melatonin for sleep.
Why Late-Night Eating Wrecks Your Sleep
Have you ever eaten a heavy meal late at night, only to find yourself staring at the ceiling, tossing and turning, or waking up with acid reflux?
That’s because eating too close to bedtime messes with both your digestive system and your circadian rhythm.
🔬 What happens when you eat too late?
1. Your digestion is still working when your body wants to sleep.
The stomach takes about 3-4 hours to empty after a meal. If you eat late, your body is still digesting while trying to power down for sleep.
2. Acid reflux is more likely.
When you lie down with a full stomach, stomach acid can easily flow back into the esophagus, causing heartburn, GERD, or that annoying 2 a.m. wake-up call.
3. Blood sugar fluctuations may disrupt sleep.
At the same time, if you find yourself consistently waking up between 2 - 3 a.m., your gut (and blood sugar) may be to blame. Spikes and crashes in blood sugar—often caused by eating too close to bedtime or consuming too many refined carbs or eating too little complex carbs at dinner —can trigger stress hormone release, disrupting sleep. In these instances, your blood sugar may either be too high or too low.
4. Melatonin production is disrupted.
Your gut and brain work in sync to regulate melatonin. When you eat late, insulin spikes, and this can interfere with melatonin release, delaying sleep.
5. Your gut microbiome gets thrown off.
Your gut bacteria operate on a rhythm just like you do. When you eat late at night, you disrupt the natural cycles of gut bacteria, leading to bloating, poor digestion, and restless sleep.
And here’s where it turns into a spiral: poor sleep itself affects blood sugar regulation, making you more likely to crave sugary, high-carb foods the next day—leading to the same cycle of late-night eating, blood sugar crashes, and restless nights all over again.
💡 Key takeaway: Eating too close to bedtime confuses your body's natural rhythms and makes sleep harder to achieve. Chronic late-night eating can contribute to long-term gut issues, including acid reflux, disrupted microbiome balance, and increased intestinal permeability (" leaky gut "). These issues impact digestion and create a cycle of inflammation, sluggish metabolism, and will disrupt your sleep.
The Ideal Eating Schedule for Deep Sleep
If the timing of when you eat affects your sleep, then what’s the best schedule?
Your Gut-Sleep Meal Timing Blueprint
✅ Breakfast: Eat a protein-rich meal within 60-120 minutes of waking up to reset your circadian rhythm and support healthy cortisol levels.
✅ Lunch: The biggest meal of the day should be around midday, when digestion is strongest.
✅ Dinner: Finish eating at least 3-4 hours before bed to give your body enough time to digest before sleep.
✅ Cut Off Snacks: Stop eating 2-3 hours before bed —no late-night snacking!
✅ Hydration: Drink water throughout the day, but cut back on fluids 1-2 hours before bed to avoid waking up to use the bathroom.
💡 Pro tip: If you’re hungry at night, sip on herbal tea like chamomile, Kava or peppermint instead of grabbing a snack. You can add a tsp of manuka or dark, buckwheat honey to the tea as well for added benefits. Like I talk about in The GutSMART Protocol , late-snack munchies are more about stress than hunger; when you calm the nervous system, the cravings also calm down and disappear.
How Fixing Your Gut Leads to Better Sleep
One of the biggest unexpected benefits of healing the gut is improved sleep. Many of my patients on the 28-Day Gut Reset tell me they start sleeping deeper within the first two weeks of resetting their gut health.
That’s because a healthy gut:
✔ Reduces inflammation, which can disrupt melatonin production.
✔ Balances blood sugar, preventing night-time wake-ups.
✔ Supports serotonin production, which leads to better mood and better sleep.
✔ Optimizes digestion, so you’re not kept awake by bloating or acid reflux.
If you want to fix your sleep, start with your gut.
8 Easy Ways to Improve Gut Health & Sleep
Here are some simple, science-backed habits to improve both your gut and your sleep quality:
1️⃣ Eat fiber-rich foods. Load up on leafy greens, fermented foods, and prebiotic-rich foods to support your gut microbiome.
2️⃣ Avoid excess sugar and processed foods. These feed bad gut bacteria, leading to inflammation that can disrupt sleep.
3️⃣ Don’t eat too late. Finish dinner at least 3-4 hours before bed to allow digestion to complete.
4️⃣ Get natural sunlight. Morning light exposure helps regulate both your gut and brain’s circadian rhythms. Studies show that spending time in bright light daily helps regulate your internal clock, leading to better sleep quality. Try stepping outside for morning sunlight exposure to set your body’s circadian rhythm for the day.
5️⃣ Avoid blue light at night. Screens delay sleep by blocking melatonin. Use blue light-blocking glasses, dim lights, and limit screens before bed to protect your sleep cycle.
6️⃣ Practice stress management. Chronic stress disrupts gut function, leading to poor sleep. Try meditation, deep breathing, or yoga.
7️⃣ Move your body. Exercise improves gut motility and enhances melatonin production—but avoid intense workouts right before bed.
8️⃣ Follow a gut-healing program. A structured reset like the 28-Day Gut Reset can help rebalance your microbiome and improve your sleep naturally.
The Bottom Line
If you’ve been struggling with poor sleep, waking up in the middle of the night, or feeling unrested, your gut health might be the missing link.
By eating at the right times, healing your gut, and balancing your gut microbiome, you can unlock the deep, restorative sleep your body craves.
And trust me—once your gut is happy, your sleep (and energy levels) will transform.
Happy Sleep Awareness Month, and here’s to gut-healthy, restful nights! 😴
What’s your biggest struggle with sleep? Drop a comment below—I’d love to help! 👇💬
