Dear Mark: Aloe Vera for Leaky Gut, One Meal a Day, and Glyphosate and Celiac Disease

Aloe VeraFor today’s edition of Dear Mark, we’ve got a three-parter. First I discuss the effect of aloe vera on gut function. Is there evidence that it’s a panacea for intestinal permeability, as so often is claimed? Next, I help an extremely active reader who’s considering switching to one meal a day to lose the last few stubborn pounds of body fat figure out what his next move should be. And finally, I explore the evidence for a connection between the herbicide glyphosate and celiac disease.

Let’s go:

I have been reading a lot about Aloe Vera juice and the claim that it’s a “miracle” potion for helping with curing leaky gut. Do you have an opinion about using this as a method for helping to heal the gut? There is also some research out there claiming that aloe juice has caused tumors in lab rats so I’m not sure what to believe.

Thanks so much for the input.


Aloe vera has traditionally been used to alleviate, soothe, and even speed up the healing time of burns on the skin (PDF). I’ve heard these claims about aloe vera as well, but never thought to look into it. The proposed mechanism I’ve seen is that aloe vera heals leaky gut the same way it heals damaged skin on the surface, almost as if swallowed aloe vera coats the intestine and starts the healing process.

Except “leaky gut” generally doesn’t involve mechanical damage to your intestines, but rather miscommunication on the cellular level. In actual leaky gut, the tight junctions that govern the passage of compounds from the gut into the bloodstream are allowing proteins and other substances through the gut lining and into your bloodstream that otherwise would not be granted passage.

With that in mind, does aloe vera help leaky gut? There’s actually evidence that aloe vera increases the leakiness of the tight junctions in your gut. Rather than keep them closed, they open them up. Some researchers are even exploring the use of aloe vera as a way to increase drug absorption via this exact mechanism.

That’s not to say aloe is useless for gut issues. It’s a powerful stimulant laxative, meaning it induces colonic contractions, increases fluid absorption in the colon, and can improve short term bouts of constipation. But it’s not a final solution, or a long term one. Long term usage of stimulant laxatives can lead to cathartic colon, a condition involving damaged colonic musculature and disrupted neuromuscular connections between the colon and brain.

If you’re going to use aloe vera for gut issues, I would suggest using it sparingly and infrequently. Consider a recent study where rats who got whole leaf aloe vera extract in their water every day for 13 weeks developed colonic tumors (both benign and malignant) more frequently than rats who did not receive aloe vera. The researchers concluded that aloe vera is an “intestinal irritant.” Irritants can be helpful hormetic stressors that improve resistance against disease when applied infrequently. When they’re applied chronically, they become agents of disease themselves. Just realize that aloe is medicine, not food.

Honestly? I don’t see how it’ll help leaky gut (and I can see how it might actually cause it or make the condition worse), but lots of people seem to swear by it. Who knows? If you try, be careful with it.

Who I am – Just turned 28, male, 170 cm tall and weight about 90 kg. I train CrossFit everyday, 5 days a week, sometimes 6 times a week. I cycle around 10k everyday and work as a cleaner and as a cook which demand of me to be standing up, moving around, and lifting stuff.

My question – To get what I want, do you think it’s a good idea to do a single meal a day, everyday. Keeping it below 2000 calories. Low carb as possible (10-30g) and with paleo ingredients only.

Fasting is easy. Controlling the amount of food I eat, not so much.

I know it’s been said that counting calories is bad but not if you’re eating paleo. This way I reckon thermodynamics do apply since you’re eliminating (controlling) hormonal response from the equation.

It might sound like I want to cover a lot, I just want to get it over with. Get the fat content I want, better my results at the gym, and be healthy before I turn 30. Everyday I move more weight than my peers in the form of fat and still keep up with them. If I loose it I’ll be able to keep with the top players.

Motivation and drive are not an issue. I just need to know this path will take me there. I realize we should tailor our diets but as a general approach, do you think it’ll work?

Thanks heaps.

Gus C

You’ve got a lot on your plate. CrossFit 5-6 times a week, 10k on the bike daily, and an active, demanding job (working a kitchen is no joke!).

Fasting can definitely speed up fat loss, and it’s a great way to inadvertently control the amount of calories you take in. Lots of people who have trouble controlling their food intake find that intermittent fasting is the most painless way to do it. So yes, it can work.

However, before you switch to one-meal-a-day, you might try making a few changes to your routine.

Here’s what I’d do:

Even though you might love it, reduce your CrossFit intake. Instead of five or six days a week, try three. Going hard every day doesn’t allow you any recovery time. Your cortisol levels are probably permanently elevated, giving you little to no let-up. Cortisol, as you may know, is heavily implicated in the storage and retention of belly fat – often the most annoyingly-persistent fat for us guys. Your performance will increase due to the recovery time, your stress levels will go down, and I strongly suspect that you will begin burning more body fat (even though you’re using fewer calories on the reduced schedule).

Cycling 10 kilometers, or six miles, isn’t much. That’s your slow movement for the day, as long as you aren’t out there sprinting between stop lights and climbing hills the entire time. I say stick with the easy cycling.

Your job is your job. You can’t do much about being on your feet all day.

Try a full dinner to dinner fast once or twice a week. So, eat dinner 8 PM on Monday and don’t eat again until 8 PM on Tuesday. Do that twice each week.

Or try what I do – a truncated eating window. I generally eat from around 1 PM to 7 PM. At this point, it’s ingrained. I don’t think about it, I just do it. And if I do get hungry, I’ll eat. I just don’t get hungry outside of the window.

Some people thrive on a single meal every day, but most do not. You have a demanding life and a very physically active existence, and I’d wager that you’d do better on a slightly different schedule. Feel free to try the one meal a day thing, but be prepared to switch it up if things don’t work. Whatever eating strategy you choose, cutting two CrossFit days will probably be the real game changer.


I was wondering if you had been following any of Stephanie Seneff’s recent…well, not sure whether to call them “findings”, but not sure if they’re totally invalid either. Just read this interview with her and was curious about your take on it.


I’ve seen that paper and even linked to it in a past Weekend Link Love. Seneff’s idea is certainly interesting, and I’ve always been more concerned by the massive amounts of Roundup used on GMO crops than the GMO crops themselves. There’s a lot to unpack in the paper, more than I have time for on Dear Mark, so I’ll just focus on what looks to be the most compelling part: the effect of Roundup/glyphosate on gut bacteria.

Let’s look at a few lines of evidence:

  • Children with celiac disease have fewer enterococcus, lactobacillus, and bifobacterum bacteria than children without celiac. That’s a a pretty standard finding – celiac disease is characterized in part by dysfunctional microbiomes.
  • Interestingly, a recent paper showed that those very same bacterial species that are reduced in celiac disease – lactobacillus, enterococcus, and bifidobacterium – are the ones most susceptible to glyphosate, while the pathogenic bacteria like salmonella and clostridium botulinium (responsible for botulism) are highly resistant to glyphosate (PDF).
  • Furthermore, glyphosate also inhibits the anti-pathogenic activity of enterococcus bacteria. One of the reasons why “beneficial bacteria” are so beneficial is that they tend to keep the pathogens at bay, and glyphosate directly interferes with it.

Even if glyphosate proves to be safe for human cells, it appears to affect the bacterial cells that outnumber our own cells, power our immune system, regulate our digestive function, and affect our brains. They count, too. Research is scant, but that’s only because the microbiome is a relatively recent concern for most. What research does exist suggests that the microbiome may be vulnerable to otherwise-safe glyphosate residues, and this alteration of the microbiome may increase gluten reactivity. It’s certainly worth further study, don’t you think?

In the meantime, I’m going to kindly excuse myself from the massively uncontrolled trial being conducted on a mostly unsuspecting population. Just to, you know, be safe. How about you?

Thanks for reading, everyone. Be sure to send in your questions, comments, and concerns, and I’ll do my best to address them in the blog or on the podcast!

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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