Previous: Hiding a Nobel Prize From the Nazis
Next: From Scarred Lungs to Diabetes: How COVID May Stick With People Long-Term | SciShow News



View count:2,960
Last sync:2020-07-02 17:30
We humans love a good health food trend, but sometimes it can be hard to sort out the facts from the fiction. So over the years, we here at SciShow have hit up the research and set the record straight.

Hosted by: Hank Green

SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at
Support SciShow by becoming a patron on Patreon:
Huge thanks go to the following Patreon supporters for helping us keep SciShow free for everyone forever:

Kevin Bealer, Jacob, Katie Marie Magnone, D.A. Noe, Charles Southerland, Eric Jensen, Christopher R Boucher, Alex Hackman, Matt Curls, Adam Brainard, Jeffrey McKishen, Scott Satovsky Jr, James Knight, Sam Buck, Chris Peters, Kevin Carpentier, Patrick D. Ashmore, Piya Shedden, Sam Lutfi, Charles George, Christoph Schwanke, Greg
Looking for SciShow elsewhere on the internet?
Links to Original Episodes and Sources:
The Sad Truth About the Turmeric in Your Golden Latte
The Truth About Chocolate and Your Health
Are Antioxidants Actually Good for Anything?
Is Alkaline Water Really Better for You?
The Truth About MSG and Your Health

 (00:00) to (02:00)


[Intro Music] Some days it can feel like everytime you open Twitter or check the news, there's some new health food trend. Like, just add this ingredient to your morning coffee and you'll be cured of all inflammation! Whatever that means. Sometimes though it's not always clear what trends are garbage and what ones are actually rooted in science.

So over the years, we've hit up the peer-reviewed research and gotten to the bottom of it. Here are some of the trends we have debunked.  First, speaking of things you might put in your coffee, there's turmeric - a lovely yellow color and coffee shops love to put it in fancy lattes. Sometimes they even claim that this magic ingredient can do SO many different good things for your body.

But, take their advice with a grain of salt. Here is Olivia with more.

 The Sad Truth About Turmeric

If you've spent any time on foodie Instagrams lately, you're probably familiar with the vibrant yellow of golden lattes. These lattes are usually made with some kind of nut milk and cinnamon, but they get their color from turmeric, a spice that's been used in Indian cuisine and ayurvedic medicine for millennia. Touted as the next miracle superfood, turmeric has some bold health claims behind it. Like, that it can prevent and even cure cancer.

And while there have been a suprising number of studies conducted on the spice, there isn't a lot of evidence to support its superfood status. The dozens of supposed health benefits of turmeric certainly seem too good to be true. People and even scientists claim it makes your skin glow, improves brain function, can prevent cancer, diabetes, and heart disease, and can even cure the uncurables, from cancer to arthritis, Alzheimer's, and more.

But the studies underlying these claims haven't really looked at the effects of turmeric-heavy diets on health. When researchers study the "medicinal effects of turmeric", most of the time, they're actually using concentrated curcumin, an active ingredient in turmeric.

 (02:00) to (04:00)

Or a mix of it and similar molecules collectively called curcuminoids.

These are polyphenols - compounds with multiple carbon rings - so they're somewhat similar in structure to the "healthy" stuff in red wines. And they also happen to be highly reactive molecules, so in lab tests, they might seem like they can do a lot.

But there's a lot of contradictory science too. For example it's often said that curcumin has health benefits because it's an antioxidant, a compound that binds to electron-hungry molecules called oxidants which can damage cells. But some studies have found it acts as an anti-antioxidant, as it can worsen the damage of these compounds or even cause damage all by itself.

Such conflicting findings tend to happen with highly reactive compounds because they don't actually solve a specific biological problem. They interfere with the lab tests being run. Biochemists have even come up with a special name for such annoying molecules: They're classified as Pan Assay Interference Compounds, or PAINS.

And curcumin earned that cheeky description because despite over 10,000 studies on the stuff, and more than 120 trials testing it for different medical conditions, there isn't really conclusive evidence that adding turmeric to your diet does anything special. That's partially because the vast majority of those trials were conducted in rats. And you know, it can't be said enough, that rats aren't people.

While they can be useful to see if something has potential, many rat cures completely fail in us. And the trials that have been conducted in people have had mixed results at best and vary widely in methodology. Those that do suggest benefits often have critical design flaws.

Like that they aren't double blinded clinical trials. Those are the gold standard studies, where neither the experiementer nor the participant knows whether they're getting the drug or a placebo to minimize the error that comes from bias. And most don't use dietary turmeric, like in a latte.

Instead they stick purified curcumin or curcuminoids in a capsule. The dose

 (04:00) to (06:00)

in that pill varies from study to study, from as low as 36 milligrams to as high as 8,000 mg per day.

Curcuminoids make up anywhere from 1-4% of turmeric powder. So to get the same amount from lattes, well, let's assume you use a generous teaspoon of ground turmeric to make your drink.

That weighs a little over 2 grams and contains anywhere from 20 to 90 mg of curcuminoids. So to down 8,000 mg, you'd have to drink between 88 and 400 lattes a day. Every day.

That's a lot of cashew milk. And it's not clear how much of the curcumin you eat actually gets into your bloodstem so that it can travel around and do the things people claim it does. That's because curcumin basically goes right through you.

In animal studies, ingested curcumin quickly ends up excreted in feces - which is why you might noticed your poops become nice and yellow after you eat curry. And in people, researchers often fail to detect any curcumin in a person's blood, even after they've consumed as much as 12 grams of the stuff. So while there are few things you can do to increase how much curcumin your body absorbs, like eating pepper or fat at the same time, even then it's really unclear if basically any curcumin you eat stays around long enough to actually do anything.

All that said, curcumin isn't the only component of turmeric. So it's possible that other things in the spice, either combined with curcumin or alone, could be good for you if eaten regularly as part of a healthy diet. Probably not, like cure your cancer good for you, but maybe a little better than the same meals without the spice?

And the good news is that turmeric as a food, and even curcumin as a supplement are thought to be pretty harmless. So you can sprinkle a large pinch of turmeric on your latte and you probably won't experience any negative side effects. Other than maybe some yellow tinted feces.

And whether you're boosting your health or not, at least you'll get a pretty yellow Instagram out of it.

[Hank] Excellent. Yellow-Tinted feces. That's what I've always wanted.

 (06:00) to (08:00)


[Hank] So long as we're talking about stuff you put into coffee, we might as well mention chocolate. Every now and then you'll hear some food blog claim that you should put dark chocolate powder in your coffee or eat a square of chocolate candy bar every day. But while there is some truth to this, you can probably guess what's up. Here's Michael with more:

[Michael] Chocolate: as if we needed anymore excuses to indulge in the sweet stuff.

There are constantly claims floating around that "Hey, chocolate might actually be good for you." There is some science to back that up, but you guessed it! The devil's in the details. Most of these claims involve flavonoids, a class of compunds found in lots of plant, including cacao, the plant whose seeds are used to make cocoa and chocolate.

Some studies have linked flavonoids to a decreased risk of heart disease. Some experimental studies, which are considered the best type of study for establishing cause and effect, have shown decreases in blood pressure when healthy adults were given specially developed high flavonoid cocoa drinks or chocolate. For example, one 2015 study found that 100 adults who drank a high cocoa chocolate drink twice a day for one month had a drop in blood pressure of around 4 millimeters of mercury, which is a measure of pressure.

And a drop of blood pressure of just 2 millimeters has been associated with the decreased risk of stroke or heart problems, at least on average within a population. There are also a few experiments that hint the flavonoids could improve blood flow to the brain, which in turn might mean better brain function. For example, a 2014 study in Nature Neuroscience found that older adults did better on a memory task, and had increased blood flow to particular memory centers in the brain, if they'd had a high-flavonoid cocoa drink for three months.

But, there are a bunch of other studies that only show changes in brain blood flow and not improvements in cognition. And there are a few key points in these experiments that mean that a candy bar now and then isn't going to give you any benefit. For one, in most of these trials it took weeks or months to see any health benefits.

And most of the cocoa drinks in the experiments were specially made to have high levels of flavonoids, between 400 and 1,000 milligrams, using cocoa that's processed differently than regular supermarket chocolate. Even 400 milligrams is more flavonoids than chocolate normally has, and you'd need to eat at least two large

 (08:00) to (10:00)

bars of regular dark chocolate every day to get that much. Even if you did, the way cocoa is processed to make it less bitter, as well as adding milk or sugar, has been shown to reduce the level of flavonoids or the body's ability to absorb them. Plus, the flavonoid enriched chocolate used in these types of experiments isn't particularly tasty. Some participants were even put off from eating it. Yeah these studies managed to make chocolate taste bad. So you won't be finding these flavonoid rich drinks and bars at the supermarket.

So overall, there is evidence that flavonoids in chocolate and other foods have a small beneficial effect on heart and maybe brain health. But how that works isn't fully understood yet and more importantly, these compounds occur in small enough quantities in your average bonbon or candy bar, that to get an effective dose, you'd have to eat quite a bit more chocolate than you should. I mean, all that sugar and fat that comes with that chocolate is going to outweigh any beenfits. So enjoy chocolate as a treat, but don't expect to be living longer because of it.

[Transition: "Sci-show"]

Well if there was some truth to that one. Also chocolate is very good and I love it. Now we couldn't make a video about health food trend without asking about a big one: antioxidents.

The obsession with them probably got started because of some seemingly convincing evidence. But the longer studies go on, the less straight-forward things seem.

[Transition: "Are Antioxidents Actually Good for Anything?"]

It seems like every week there's a news article claiming you shoudl consume more antioxidents be it through fancy smoothies or sciency sounding supplements. This antioxident craze goes back a long time to the 80s and early 90s when some early research suggested antioxidents could maybe protect against certain diseases. Food and supplement companies jumped on that research and have been touting the benefits of antioxidents ever since.

But the follow-up research investifating those benefits has actually been pretty inconsistent and scientists aren't totally sure why yet. Health food commercials will give you the impression that an antioxident is a thing, a healthy thing you should be eating and drinking.

 (10:00) to (12:00)

But chemically, the word antioxident is actually more of an adjective than a noun. It describes a range of chemicals and enzymes that can neutralize free radicals: compounds with single, unpaired electrons. Free radicals can cause real havoc in our cells: altering DNA, damaging the proteins our cells need to function, and messing with the sophisticated membranes holding everything together. And these free radicals can come from practically anywhere: From the food we eat, to the air we breathe- even sunlight can profuce free radicals in our bodies.

Now our cells try to contain them by employing a large network of antioxident chemicals and enzymes to deactivate the different types of free radicals our bodies encounter. But when the amount of free radicals being produced outpaces the rate at which our bodies can quench them, our cells enter a state known as oxidative stress. Unfortunately slipping into a bubble bath and decompressing with an episode of Queer Eye is not a viable way for our cells to de-stress though that does work for my mind.

And if our cells stay oxidatively stressed for long periods of time, there can be serious health consequences. In the 80s and 90s, scientists started gathering evidence that cancer, heart and neurdegenerative diseases, the negative side effects from aging could all be linked to damage from oxidative stress-- at least, in part.

Research during that time also found that a Mediterranean diet, which is rich in antioxidents, was associated with a lower incidence of those diseases. Scientists put two and two together that supplementing people's diets with antioxidents might prevent or even reverse the provlems associated with these diseases.

It's an elegant idea, but unfortunately, it's been difficult to find support for. Researches began by looking at how supplementing single antioxidant chemicals woudl affect cells grown in test tubes and saw some promising results. For example, studies showed that chemicals like vitamin E could successfully act as antioxidants to reduce damage from oxidative stress in cell membranes. But when they tried to extend the beenfits that

 (12:00) to (14:00)

 (14:00) to (16:00)

 (16:00) to (18:00)

 (18:00) to (20:00)

 (20:00) to (22:00)

 (22:00) to (24:00)

 (24:00) to (26:00)

 (26:00) to (27:11)