Is soy bad for you? - Francesca Bot

593,054 views ・ 2022-03-03

TED-Ed


Please double-click on the English subtitles below to play the video.

00:07
In the 1930s, American industrialist Henry Ford had one overwhelming obsession:
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soybeans.
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He extracted their oil to make enamel for painting his cars.
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He crushed them into powder to make plastic parts.
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And he encouraged American farmers to grow as much of the plant as possible.
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But he wasn’t just feeding soy to machines.
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At the Chicago World’s Fair, he hosted a soy-centric feast.
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The ingredient had been a staple in Asian cuisine for centuries,
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but Ford’s dinner— full of soy substitutes for dairy, meat and wheat—
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took the integration of soy into food a step further.
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Today, soy is in so many foods that most people consume it every day
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without even knowing it.
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So what makes soybeans so versatile?
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And is our global obsession healthy or harmful?
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Soybeans have been cultivated in Asia as early as 5,500 years ago,
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but since then they’ve spread across the globe.
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01:01
Part of soy’s success is that the crop can be grown easily and cheaply
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in variable conditions.
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And once they’re grown,
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soybeans have an incredibly high density of proteins and fats;
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ingredients which in recent years have been used in everything
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from mayonnaise to biodegradable plastic.
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The ideal method for separating these components
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depends on what you’re trying to extract.
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To isolate soy proteins, dehulled beans are sometimes pressed through rollers
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to create thin flakes, and then steeped in water to draw out the proteins.
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Alternatively, whole beans can be simply soaked and ground
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into a whitish, protein rich liquid.
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In both cases, the resulting substance can be used to make spongy foods
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like tofu or filtered to produce soymilk.
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And at the industrial scale,
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these proteins can be used in various ways to help make processed foods.
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Soy fats may be even more versatile.
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In one extraction method,
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soybeans are dried, cleaned, and then fed into an extruder.
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This machine simultaneously heats and presses the beans,
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producing a liquid containing soy oil and other fatty components.
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By adding water and spinning the mixture, components are separated into two parts:
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refined soy oil for things like salad dressing, and a substance called lecithin.
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Lecithin is made of molecules called phospholipids,
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which have a phosphate head that attracts water and a tail that attracts fats.
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These features make phospholipids excellent for blending ingredients
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that naturally separate from each other.
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This process is called emulsification
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and soy lecithins are used as an emulsifying agent
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in a huge variety of foods.
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For example, during chocolate production
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phospholipids attach to both the fatty components of the cocoa butter
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and the water-soluble sugar particles,
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making them easier to combine into a smooth mixture.
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A similar process happens in powdered products
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that need to be instantly rehydrated.
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Soy lecithin bonds with the water
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and helps the powder disperse more quickly.
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While there are other plants we can process for lecithin and proteins,
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soy’s mild taste and widespread availability
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have earned it a place in thousands of food products.
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But is it unhealthy to be eating this much soy?
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Not really.
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Soybeans contain many of the essential amino acids our bodies need,
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making them one of the best ways to get these proteins without eating meat.
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And the beans’ fat content is largely made up of so-called “good” fats—
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poly and mono-unsaturated fatty acids,
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which can decrease cholesterol and reduce the risk of heart disease.
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There are some compounds in soy
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that may inhibit our body’s absorption of various minerals.
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And about 0.3% of the general population has a soy allergy,
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which can be severe in rare cases.
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But for many people, the biggest complaint about soy consumption
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is the occasional increase in flatulence.
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Outside our bodies however, soy is much more worrying.
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To accommodate the soy farms needed for heavy industry,
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processed foods and livestock feed, huge swaths of land have been deforested.
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Between 2006 and 2017, roughly 22,000 square kilometers of the Amazon
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were cleared for soy production.
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In some regions, this has also led to the displacement of farmers
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and indigenous communities.
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So if we want to keep using soy and all its byproducts,
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we’ll need to find a way to do it humanely and sustainably.
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