Trying to stay healthy can seem like a full-time job sometimes. Especially during a pandemic. But I’m here to make that goal a little easier. Welcome to the Nutrition Facts podcast, I’m your host Dr. Michael Greger.
It’s time for the Nutrition Facts grab bag, where we look at the latest science on a whole variety of topics. Starting today with pine nuts. Did you know that some pine nuts cause a bad taste in your mouth that can last for weeks?
The reason I make my pesto with walnuts instead of the more traditional pine nuts is not only because walnuts are probably healthier—we’re talkin’ 20 times more polyphenols—but also because of a mysterious phenomenon known as PMS. Nope, not that PMS. “Pine Mouth Syndrome,” characterized by what has become my favorite word of the week, cacogeusia, meaning a bad taste in your mouth. You can get it from heavy metal toxicity, seafood toxins, certain nutritional and neurologic disorders, or from eating the wrong kind of pine nuts. “Termed ‘Pine Mouth’ by the public,” a few days after eating pine nuts, you get this persistent metallic or bitter taste in your mouth that can last for weeks.
Thousands of cases have been reported. Raw versus cooked pine nuts doesn’t seem to matter. Could the cause be some “unidentified toxin present in some varieties of non-edible pine nuts”? “Out of more than 100 different [kinds] of [pine trees, the nuts of only about 30 are considered to be edible…”
So, pine nut samples from stricken consumers were analyzed, and indeed, they all contained nuts from Chinese white pine, which is not reported to be edible. That tree is typically used only for lumber. These are the good ones; these are the bad ones. It’s like a game: good, bad, good, good. You don’t know it’s the Chinese white pine nuts, though, until you put it to the test.
Researchers had a few folks consume six to eight Chinese white pine nuts. Most of the subjects hadn’t ever heard of Pine Mouth Syndrome, and boom—they all developed symptoms. We still don’t know exactly what it is in those nuts that causes such a weird reaction. We just know to stay away from those kinds of pine nuts.
So, what kinds of pine nuts do we have on our shelves here? All kinds, apparently, including those associated with pine mouth. So, unsurprisingly, hundreds of cases have been reported in the U.S. as well. Most of the implicated nuts were “[reportedly labeled as]…originating from Asia, and in most cases China.”
Europe actually did something about it and demanded China stop sending them toxic nuts, which they did in 2011. And “this export restriction likely resulted in [less being imported into] the U.S. as well,” given the decline in cases going into 2012. Rare cases still happen, though, as evidenced by an active Facebook group entitled “Damn You Pine Nuts.” Although there are no proven therapies, Pine Mouth Syndrome appears to be benign and just goes away on its own.
In our next story we look at how emulsifiers are the most widely used food additive. What are they doing to our gut microbiome?
Today, when grocery shopping, unless you’re sticking to the produce aisle, “[it’s] nearly impossible to avoid processed foods, particularly…” if you’re eating the standard American diet, characterized not only by insufficient plant foods and too much meat, dairy, and eggs, but also lots of processed junk – and along with that, an “increased exposure to [food] additives…”.
For example, the artificial sweetener sucralose, sold as Splenda, can disrupt the human gut microbiome, and “induce glucose intolerance.” In other words, it can make your blood sugars worse instead of better. It’s relatively easy to avoid artificial sweeteners, but “it may be … more difﬁcult to avoid ingestion of emulsiﬁers…because they are commonly added to [so many] foods.” In fact, “emulsifiers are the most widely used food additives,” and “most processed foods contain one or more [of them].” We now consume emulsifiers by the megaton every year, thanks to a multibillion-dollar industry.
You’ll commonly find emulsifiers in fatty dressings, fatty spreads, baked goods, mayonnaise, salad dressings, candy, and beverages. Why do we care? “Like all authorized food additives, emulsiﬁers have been evaluated by risk assessors, who consider them as safe.” However, there are growing concerns among scientists about their [potentially] harmful effects on [our intestinal barrier]” in terms of causing a leaky gut, as well as their effects on our microbiome. Moreover, they could possibly “increase the absorption of…environmental toxins” present in the food.
We know that the consumption of ultra-processed foods may be a contributor to weight gain, for example. Healthier, longer-lived populations don’t just have low meat intake and high plant intake, but they are eating minimally-processed foods. Maybe the emulsifiers found in processed foods could be playing a role, based on a number of preclinical studies. But who cares if “emulsifiers make rats gain weight”? When you read that “emulsiﬁers can cause striking changes in the microbiota,” they’re not talking about within human beings.
Mice are often used to study diet’s impact on the microbiome, but we only share “a few percent of…bacterial genes” in common. Even the gut flora of different mouse strains can be considerably different from each other; so, if you can’t even extrapolate from one type of mouse to another, how are you supposed to translate results from mice to human beings? “Remarkably, there has been little study of the potential harmful effects of ingested . . . emulsiﬁers in [us].”
For example, lecithin, perhaps best known as a key component of egg yolks, was found to be worse than polysorbate 80 in terms of allowing bacteria to leak through the gut wall into the bloodstream. But whether lecithin consumption in humans causes the same problem is yet to be determined. “There is certainly a paucity…of human trials [on] the effects of emulsifiers in processed foods,” but we at least have data on human tissue, cells, and gut flora.
“Dietary emulsifiers directly alter the [composition of the human microbiome]…ex vivo…potentiating intestinal inflammation”. Ex vivo means outside the body. Researchers inoculated an artificial gut with fresh human feces until they had a nice stable culture going, and then added carboxymethylcellulose or polysorbate 80, and got a boost in proinflammatory potential, starting within one day with the carboxymethylcellulose, and within the first week with polysorbate 80. “This approach revealed that both [emulsifiers] acted directly upon human gut [bugs] to increase [their] proinﬂammatory potential.” If you then test the effect of these emulsifiers on the protective mucus layer in petri dish cultures of human gut lining cells, you will find they can partially disrupt the protecting layer. But both this study and the last-used emulsifier concentrations were far in excess of what people might typically get day-to-day.
This is probably the study that raised the greatest potential concern. The researchers surgically obtained not just cells, but actual intestinal wall tissue, and found that polysorbate 80 could double the invasion of E. coli through the intestinal lining tissue, whereas adding fiber (in this case, fiber from plantains) could seal up the gut wall tissue twice as tight.
In our final story today, we look at how the spice cumin can work as well as orlistat, the “anal leakage” obesity drug.
In my video Benefits of Black Cumin for Weight Loss, a total of 17 randomized controlled trials showed that the simple spice could reduce cholesterol and triglycerides. And the side effects? A weight-loss effect.
Saffron is another spice found to be effective for treating a major cause of suffering (depression, in this case) with a side effect of decreased appetite. When put to the test in a randomized, double-blind, placebo-controlled trial, saffron, indeed, was found to lead to a significant weight loss (five pounds more than placebo, and an extra inch off the waist in eight weeks). The dose of saffron used in the study was the equivalent of drinking a cup of tea made from a large pinch of saffron threads.
Suspecting the active ingredient might be crocin, the pigment in saffron that accounts for its crimson color, researchers also tried giving people just the purified pigment. That led to weight loss too, but it didn’t do as well as the full saffron extract (beating the placebo by only two pounds and half an inch). The mechanism appeared to be appetite suppression, as the crocin group ended up averaging about 80 fewer calories a day, whereas the full saffron group consumed 170 calories less a day on average.
A similar study looked specifically at snacking frequency. The researchers thought perhaps the mood-boosting effects of saffron might cut down on stress-related eating. Indeed, eight weeks of a saffron extract did cut snack intake in half, compared to placebo, accompanied by a slight but statistically significant weight loss (about two pounds). Even the loss of a few pounds is pretty remarkable, given the tiny doses utilized (about 100mg), which is equivalent of about an eighth of a teaspoon of the spice.
The problem is that saffron is the most expensive spice in the world. It’s composed of delicate threads sticking up out of the saffron crocus flower. Each flower produces only a few threads; so, you need 50,000 flowers to make a single pound of spice—enough flowers to cover a football field. So, that pinch of saffron could cost a dollar a day.
That’s why in my 21 tweaks to accelerate weight loss in How Not to Diet, instead of saffron, I include black cumin, which at a quarter teaspoon a day would only cost three cents a day. But what about just regular cumin?
Used in cuisines around the world from Tex-Mex to South Asia, cumin is the second most popular spice on earth, after black pepper. It is one of the oldest cultivated plants with a range of purported medicinal uses, but only recently has it been put to the test for weight loss. Those randomized to a half teaspoon at both lunch and dinner over three months lost about four more pounds and an extra inch off their waist. The spice was found comparable to the obesity drug known as orlistat.
For those of you who don’t remember, that’s the “anal leakage” drug you may have heard about (sold under the brand names Alli and Xenical), though the drug company apparently prefers the term “faecal spotting” to describe the rectal discharge it causes.
The drug company’s website offered some helpful tips, though: “It’s probably a smart idea to wear dark pants. and bring a change of clothes with you to work.” You know, just in case their drug causes you to crap your pants at work.
I think I’ll stick with the cumin, thank you very much.
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