I have a piece on the microbiome in metabolic syndrome and obesity in Mother Jones. A few things bear mentioning.
First off, the takeaway of this piece is not to go out and drink OJ with your bacon cheeseburger and fries. It’s to avoid refined food generally, and steer toward real food, like oranges, other fruits, veggies and whole grains. They feed your beneficial bacteria.
Second, I noticed one comment on Twitter questioning the study that leads off the article. In one study, Paresh Dandona found that OJ was anti-inflammatory, while sugar water was pro-inflammatory.
And then he found that freshly squeezed OJ could actually prevent the inflammation normally induced by a high fat, high-carb McDonald’s breakfast.
The tweet mentions that Dandona’s study was underwritten by Florida Citrus, a state agency. That’s true, and mentioned in the text. The implication of the tweet, though, is that the study is therefore bunk.
Clearly this person did not read the piece very carefully.
Here’s the deal:
1) Dandona discovery of the non-inflammatory effects of OJ PRECEDE the underwritten study by a number of years. It’s because of these initial findings, which were SPONTANEOUS, that the state agency contacted him to begin with. This is stated in the article.
2) Others have also shown OJ is anti-inflammatory. These researchers have nothing to do with either Dandona or Florida Citrus. So you have replication. This is also stated in the article.
3) Epidemiological studies don’t contradict the idea that consumption of OJ and grapefruit juice DOES NOT NECESSARILY CORRELATE with diabetes, while sugar-added drinks very clearly do. In this one, consumption of sugary drinks correlates with diabetes, but consumption of grapefruit and orange juice does not. (Note that “fruit drinks” are not the same as OJ and GJ)
Here’s another where there’s no positive association with fruit juice generally.
4) Dandona has discovered many things to be anti-inflammatory, including a fiber-enriched breakfast with fruit, and even a packet of fiber consumed with a fast food meal (not yet pubbed.) He’s not only looking at OJ, in other words. These facts are also in the article.
5) The idea that prebiotic fibers and / or polyphenols are anti-inflammatory ain’t some outlier of a finding that no one can replicate. Everyone in the piece has their hand on this elephant, and many many more. That’s the meat and sinew of the article. There’s a rather huge literature on the anti-oxidant, anti-inflammatory, anti-carcinogenic and anti-atherosclerotic effect of flavonoids and other polyphenols (e.g resveratrol, the stuff in red wine). Flavonoids abound in OJ.
Here’s a recent review on flavonoids:
And here’s one that discusses how flavonoids may affect the microbiome.
So on some level, Dandona’s finds aren’t too surprising — although, yes, I continue to be impressed that OJ alone could counteract an entire two-sandwich breakfast with hash browns.
On to more interesting stuff.
ENDOTOXEMIA
Endotoxin is the stuff in the outer membranes of Gram-negative bacteria that seems to leak through the gut barrier in the context of a high-fat, high-carb diet. It then causes systemic inflammation. That inflammation may drive metabolic dysfunction and lead to obesity. That’s the hypothesis explored in the piece.
Several interesting things about endotoxemia didn’t make the cut. First, although it’s mentioned very vaguely in the piece, a high fructose diet will cause this same endotoxemia in rodents. That’s work by Ina Bergheim in Germany showing that it prompts bacterial overgrowth, endotoxemia and insulin resistance.
(Also, Pauline Lund shows that the inflammation begins in the small intestine before it can be detected anywhere else.)
Monkeys put on a high-fructose diet also develop metabolic syndrome. Although endotoxemia wasn’t gauged in this study, I bet it’s there.
Here’s the lesson: Fats are complicated, sugars not as much. So there’s some wisdom to the idea of cutting out refined sugars. They’re easier to avoid than fats in some respects. Just stop with the sodas and sweets.
Now some interesting studies on endotoxemia in humans. First, yes, obese people have more endotoxin floating around. And the more they have, the worse their metabolic dysfunction.
In this study, low-dose endotoxin was given to volunteers to confirm that what occurs in mice also occurs in humans. Their fat tissue became inflamed and insulin resistant.
In this study, going on a junkfoody diet for a month increased circulating endotoxin and insulin resistance. A “healthy heart” diet did not cause this change.
And obese people generally seem to have a more permeable gut, which correlates with symptom severity. Read: more bacterial detritus leaking through.
So what seems true in mice also appears to hold in people. That said, no one I interviewed thinks endotoxin is the whole story. If endotoxin is leaking through, other bacterial byproducts are as well.
Ina Bergheim finds that a number of toll-like receptors are up-regulated—nine in total. Toll-like receptors are each specific for molecular patterns on just certain microbes, food and parasites. Endotoxin binds to just TLR4. That many more are active suggests much more is leaking through to activate them.
One final thing that’s interesting. It seems extremely important that germ-free mice can gorge on fatty food without developing problems. That strongly implicates the microbiota in Met S and obesity. But maybe that’s because they don’t have a fully functioning immune system. After all, microbes jumpstart the immune system. So germ-free mice maybe don’t mount a response because they have nothing to mount it with. It’s all a fluke, perhaps, of the human-created germ-free mouse.
Well, it turns out that even germy mice are protected from the metabolic havoc of junkfood — if they also take antibiotics.
So, they have a fully functioning immune system, but with their bugs kept in check, they can tolerate the high-fructose diet no problem. More evidence that microbes contribute to metabolic syndrome.
It makes one wonder if antibiotics might ever be used to aid in weight loss, similar to how they were recently shown to help children recover from malnourishment.
