If you’re someone with a gut problem, you’ve probably been taken on the rollercoaster of restrictive dieting, boatloads of supplements, and pharmaceutical drugs that give waning symptom relief.  And what do you have to show for it?  Probably not a whole lot.

One area that I’ve found is almost entirely unexplored by most people, and the primary topic this blog is centered around, is lifestyle.  Our behavior drives a lot of what goes on in our body, from the tips of your toes to the top of your head.  And this most certainly includes what happens in your gut.

Factors such as exercise, meal timing, the feeding/fasting cycle, stress, sleep, habitual diet, and diet quality are all very important factors that can play a major role in our gut health.  But there is one insidious habit that all of us are guilty of that may be particularly damaging: late night eating.

Hyperglycemia and leaky gut

You all may remember a blog I did a few months back on a study showing how hyperglycemia causes leaky gut in mice, and bacterial load in the blood of humans correlates with hemoglobin A1c, a 3 month average of blood glucose.  If you didn’t read that one, you can check it out here.  I also covered some of the ways that hyperglycemia is damaging to the gut here.

While this study should scare the bejeebers out of you if you have Type 2 diabetes, I think eating late at night is a much greater cause for concern, even in healthy people.  In the study, they found that hyperglycemia induced leaky gut by increasing non-insulin mediated glucose uptake by enterocytes via the GLUT2 transporter.  Blocking GLUT2 glucose transport prevented leaky gut.

Fortunately, provided you are insulin sensitive and produce adequate amounts of insulin, insulin causes you to absorb glucose via GLUT4 transporters.  This effect protects against leaky gut, but it’s an effect you won’t have great control over if you eat at night.

Why eating at night is particularly harmful

So you may be wondering to yourself, what does this have to do with eating at night?  Well, unfortunately, we just aren’t wired to process carbohydrate very well at night.  This is actually a protective mechanism gone awry in modern times

For millenia, it just wasn’t all that common to eat a significant amount of food at night.  Not only was it uncommon, it was probably quite rare.  As such, there has to be a way to make sure that our blood glucose doesn’t crash overnight while we sleep.  Enter melatonin.

After the Sun goes down and light becomes dark, we begin secreting the hormone melatonin to help induce sleep.  An artifact of this secretion is that melatonin inhibits insulin secretion by the pancreas.  By blocking insulin secretion, this ensures that blood glucose will remain stable through the night and prevent insulin sensitive tissues from sucking up all the glucose, tanking blood glucose level and starving the brain.

But this presents a problem.  If you consume food late at night, especially food high in carbohydrate, this causes blood glucose levels to climb.  If insulin secretion is blocked at the same time, this not only causes hyperglycemia, it increases GLUT2 mediated glucose transport in the gut.  This essentially recreates the conditions causing leaky gut in mice.

Of course, having Type 2 diabetes is a much larger issue than simply eating at night, but I certainly wouldn’t make a regular habit of eating right before bed.

Conclusion

Lifestyle plays a substantial role in how our gut functions.  The long term consequences of prolonged hyperglycemia can cause a significant amount of damage to the gut by damaging the enter and vagus nerves.  This will manifest itself in impaired motility, poor gut-brain communication, and delayed gastric emptying.

But damage to the gut from hyperglycemia isn’t reserved to people with Type 2 diabetes.  Given the data in mice and corresponding data in humans linking hemoglobin A1c to increased translocation of bacteria from the gut to the blood, you may want to avoid snacking at night, particularly with higher carbohydrate offerings.

A high carb load coupled with inhibited insulin secretion from melatonin at night could spell disaster for your gut health by increasing “leaky gut”.  If this is something you habitually do and you have gut problems, it may be a good idea to stop.