Transcription
You guys, I am not exaggerating when I tell you this paper just changed the way I see fiber. Fiber, fiber. Now, it didn't make me a fiber evangelical. I'm not going to argue in this video that fiber is essential. You needed to poop or any of that, pardon my language, crap. Rather, when I finished reading this paper, I sat back and let loose a big sigh of relief. Finally, I thought, after reading thousands of fiber papers, a fiber paper that's not fluff. This paper shows how a specific fiber, through a precise mechanism, can immunize the body against sugar. And what that sugar becomes will blow your mind.
So, I want to go on a scientific journey with you. I'm going on an adventure. Whether you're already a fiber fan or just a curious carnivore, come with me on this journey, and I promise I'll have you saying, "Holy crap," and not because I changed your bowel habits. So, let's get into it. Can you immunize against fructose? Partially or completely reversed reduced insulin levels by about 70%? And then I'll show you something I totally wasn't expecting and how it diverges from the usual stories we hear about fiber. And when you get through here, don't forget to check out the associated newsletter linked below, where you can find more practical suggestions to help you digest these data, the data we're going to review here, into lifestyle actions if you so choose.
Now, with that, let's first take a step back and knock out some background. Metabolic dysfunction associated stato, MASH, which is just medical jargon for fatty liver. I don't know why scientists do this, they just do. It's a serious health risk. MASH, fatty liver, worsens cardiovascular health. It increases cancer risk, and it contributes to many other chronic diseases. In fact, even independent of obesity, MASH, fatty liver, can be induced, including by, say, the simple sugar fructose. It can promote fatty liver by uniquely enhancing the synthesis of new fat in the liver. This is known as de novo lipogenesis, literally translating to the new generation of fat. And this can, in fact, be uncoupled from weight gain. For example, controlled animal experiments show that if you feed animals, say, a chow diet supplemented with high fructose corn syrup, they can not gain much, if any, weight, but they do gain fat, lose lean mass, and develop fatty liver. So, yes, you can turn from fit and fabulous into a mushy metabolic mess at the same weight. It's like the worst body recomp ever.
Now, one no-duh solution is to reduce or eliminate fructose consumption. But if you were the kind of person who was satisfied with the keep-it-simple-stupid answer, would you still be watching this video? I bet not. So, let's ask a far more interesting question. Can you immunize against fructose? Interestingly, there are data, including human double-blinded randomized control trial data, showing that the fiber inulin can improve metabolic health and insulin sensitivity in patients with insulin resistance and diabetes. See the newsletter for more information on that. But what is inulin? Inulin is a prebiotic fiber that can be metabolized by the microbiome. It is composed of a single glucose molecule head linked to a chain of about two to 100 fructose units. I imagine it kind of like a snake with a glucose head and this long fructose tail. So, it sounds like a long-shot hypothesis, but bear with me. Could inulin immunize against fructose?
To test this idea in a controlled setting and build upon the human control trial data, researchers fed mice one of several diets, actually five. A standard chow control diet, a diet with added inulin, a diet with added fructose, a diet with added fructose and inulin, and then a final fifth group that started with the fructose-supplemented diet and then switched to the fructose plus inulin diet after 16 weeks. So, with that, those were the five groups. Let's walk through the data together. The results landed with quite a bang. No, not a fart bang. Come on, get your head out of the gutter. Whereas fructose increased fatty liver, body fat, fasting glucose, insulin levels, and insulin resistance, the addition of inulin either partially or completely reversed these harmful metabolic effects. But I want to walk you through some of the figures so you don't have to just take my word for it. I want to prove the point with images. These figures show percent body fat. Fructose feeding increased percent body fat even without a significant change in total weight. But the addition of inulin on the background of fructose intake throughout the study, or even just starting at 16 weeks, lowered body fat percentage significantly.
Now, let's change to look at metabolic health markers. We're looking at insulin levels here. Fructose feeding resulted in elevated insulin levels, a marker of worse metabolic health. Whereas the addition of inulin on the background of fructose intake, again, throughout the study or even just starting at the 16-week time point, reduced insulin levels by about 70%, and this was associated with a large improvement in insulin resistance score. That's pretty amazing. But now, let's look inside the liver. This is a stain, an H&E stain of the liver that reveals fat accumulation. The white blobs are liver fat, and clearly, fructose feeding increases liver fat, causes fatty liver. But again, the addition of inulin on the background of fructose intake throughout, or even starting at the 16-week time point, improved fatty liver substantially. That's pretty incredible, right?
Now, have I wet your intellectual appetite? Good, because what's coming is even cooler. Let's first chat mechanism. How specifically does inulin improve metabolic health? And then I'll show you something I totally wasn't expecting that left my jaw on the floor. Okay, on mechanism. First, let me just say, when it comes to the methodology, I could science believe with terms like quantitative hepatic de novo epigenesis flux analysis using deuterated hydrogen labeled saponified palmitate percentage. Breathe, Nick. Breathe. Okay, I could say that, or I could use any number of multi-syllabic enzyme names, but I'm not trying to raise a tribe of Sheldon Coopers here. What? So, let me aim for that sweet spot between complexity and nuance. I want to make this understandable, and at the end, please, in the comments, tell me how I did. Okay, let's get into it.
Fructose metabolism starts well before any fructose even gets to the liver. It starts in the intestines. The small intestine comes before the large intestine, also known as the colon. And in general, this is a good rule of thumb to know for fructose: you don't want fructose to even reach the colon. It can wreak havoc on the microbiome. This phenomenon is sometimes called fructose spillover, including in the paper, fructose spillover, where excess fructose bypasses the small intestine, and it can end up getting to the colon and screwing up the microbiome, or getting spilled over into the liver. So, very simply put, you don't want spillover. No spillover means very little fructose is reaching the colon or the liver, and that is good. That is as simple as I can make it.
Now, the researchers traced the metabolic fate of fructose and found that when inulin was given, fructose spillover was dramatically reduced. The liver and the colon were protected against fructose spillover by inulin. In brief, fructose was being catabolized, broken down in the small intestine, specifically a region called the jejunum, which, every time I say that word, by the way, it reminds me of Robin Williams' character from the movie Jumanji. I don't know why I felt the need to share that, but let me not constipate your neurons with useless information. Let's get back on track.
Now, I want to ask the question: what is the effect on liver health of protecting against fructose spillover? Well, in protecting the liver from fructose spillover, inulin led to a positive shift in liver gene expression. This included decreased activation of pathways involved in de novo lipogenesis. Again, remember, the synthesis of new fat. And as a metabolic bonus, since de novo lipogenesis products actually inhibit fat burning, fatty acid oxidation, reducing spillover of fructose also removes the brakes on fat burning in the liver. So, it's a one-two punch for liver health. Less fat is being created, less de novo lipogenesis, and more fat is being burned. The obvious results are improvements in liver fat, insulin resistance, and overall metabolic health. Now, that's pretty cool, if I do say so myself, and if the story stopped there, I'd already be impressed. But it doesn't. It gets better.
So, another question: what actually happens to the carbons from fructose? Where do they go? They don't just poof go away. So, where are they directed to? Are you ready to have your mind blown? Quoting from the paper, "Unexpectedly, mice fed a high fructose corn syrup diet with inulin exhibited high labeling of glycine and serine." In simple terms, fructose carbons, the carbon atoms that make up fructose, were being redirected by inulin into the reduction of amino acids, to the production of building blocks of proteins. That's remarkable, right? Inulin's redirecting fructose carbons into protein. But it gets even better. Those particular amino acids can be combined into a tripeptide, three-amino acid chain called, you might have heard of it, glutathione. It's one of the body's key antioxidants.
So, to recap, inulin helped redirect fructose metabolism to decrease the generation of new fat in the liver, decrease de novo lipogenesis, increase fat burning, burning of stored fat, generate protein-building amino acids, and then synthesize glutathione, a major antioxidant that protects whole-body and liver health. I really want to emphasize, please hear me, how interesting this mechanism is and how it diverges from the usual stories we hear about fiber. The story we're revealing here together is one in which a specific fructose polymer immunizes the microbiome and shifts the metabolic fate of fructose sugar away from fat production and towards protein synthesis and antioxidant generation. But how cool is that?
But I know you probably throttle me if I didn't give you the answer to the obvious question: how do you actually get more inulin in your diet if you want it? So, let me give you a list of the top foods rich in inulin. There's chicory root, Jerusalem artichoke, that's my favorite, garlic, leeks, asparagus. And as a practical tip, cooking these vegetables can actually reduce inulin content, partly because it leeches the inulin into the surrounding water. I can't tolerate these vegetables raw. So, practically stated, roasting or sautéing may preserve more inulin than boiling, and also help with the digestion. In terms of dosing, 10 grams per day has been shown in human studies to improve metabolic health. And if you want to see how this actually translates into whole food equivalents, please again see the associated newsletter.
Now, for what I'm doing personally. Well, frankly, when it comes to fructose, it's a moot point. I basically don't eat any. Maybe a couple wild blueberries now and then, but very little fructose. That said, this is one of those papers that pushed me to think more deeply and differently about prebiotics and metabolism. I love that. I love when a paper challenges my preconceived notions and has me see the metabolic world differently. So, to that extent, I'm uptitrating my intake of inulin-rich foods to gastrointestinal tolerance. I'm starting with one serving of Jerusalem artichoke every other day, alternating with one or two servings of sauerkraut, which is my preferred low-sugar fermented food, as well as pickled olives and quark for cheese for extra tang and probiotic punching because it's freaking delicious. And as usual, protocols are dictated by personal preferences, including taste preferences and tolerances. These are foods that I already genuinely love, and these are doses that I'm finding I tolerate well. But with that, I'll ask the community. I'll ask you, which, if any, of these foods do you eat today? And are you going to change your behavior based on the data I just shared?
But wrapping up, in a world where nutrition advice is often vague and oversimplified, this paper, to me, stands out, showing us that not all fibers are created equal, and that a specific fiber, inulin, can fundamentally rewire how bodies respond to a common metabolic stressor, sugar, specifically fructose. From reducing fat production, reducing de novo lipogenesis, to boosting antioxidant capacity through the generation of new proteins. The data are interesting, at least, if not clear. This is not just about digestion or bulking stool. It's about deep metabolic resilience, deep thought, and of course, you know what's coming: staying curious. Thank you for listening. Now, tell me, did I blow your mind? Hope so.
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