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This Essential Vitamin Came from Outer Space

Some of that vitamin B3 in your sandwich—an essential nutrient—came crashing to Earth on a meteroid.
Image: Wikimedia Commons

If you're of the mind that vitamins lost their luster as soon as they stopped being shaped like the Flintstones, science is here to rekindle that flame. Penn State researchers working at NASA's Goddard Center for Astrobiology discovered evidence that vitamin B3 may have been originally delivered to Earth on a carbon-rich meteorite. Vitamin B3, also known as nicotinic acid or niacin, is an essential human nutrient, but it turns out it's also an interstellar traveler.

A paper published in the journal Geochimica et Cosmochimica Acta describes how the researchers analyzed eight carbon-rich meteorites and found that the samples were loaded with vitamin B3 and other organic compounds, such as pyridine carboxylic and dicarboxylic acids. And even if it turns out that the compounds didn't first arrive on Earth aboard meteorites, vitamin B3 was found on all eight of these carbonaceous chondrites.

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"It is always difficult to put a value on the connection between meteorites and the origin of life; for example, earlier work has shown that vitamin B3 could have been produced non-biologically on ancient Earth, but it's possible that an added source of vitamin B3 could have been helpful," said the study's lead author, Karen Smith, in a release.

As the meteorites were found on Earth, naturally, there's a chance that the contamination worked the other way—the familiar compounds contaminated the space rocks. However, the research team was fairly confident that because the vitamin B3 was found along with its structural isomers—molecules that have the same chemical formula, but whose atoms are attached in a different order, and are only produced through non-biological chemistry—the vitamin B3 they discovered originated in space.

Other evidence supporting the hypothesis that vitamin B3 came from elsewhere involves what the conditions on ancient Earth were like—wet and harsh. Geochemist Steven Benner argues that life probably originated on Mars rather than Earth, because, among other reasons, Mars wasn't as covered by water as early Earth. Water would have prevented sufficient concentrations of boron forming for life and also would have also been corrosive to RNA, which is believed to be the first genetic molecule to appear on Earth, Benner told The Guardian. There is also evidence that water was hard on the organic compounds that Smith and her team found.

"We discovered a pattern—less vitamin B3 (and other pyridine carboxylic acids) was found in meteorites that came from asteroids that were more altered by liquid water. One possibility may be that these molecules were destroyed during the prolonged contact with liquid water," Smith said. "We also performed preliminary laboratory experiments simulating conditions in interstellar space and showed that the synthesis of vitamin B3 and other pyridine carboxylic acids might be possible on ice grains."

During the eras of greatest bombardment, researchers believe that comets and asteroids may have brought as much as 10 trillion kilograms of organic matter to Earth every year. It's possible that the first traces of vitamin B3 arrived this way, which is cool, even if now it's so common that it's probably in a bunch of things you already ate today.

Other evidence of life's ingredients coming to Earth from beyond include the Tagish Lake meteorite, which exploded in the atmosphere over northern British Columbia in January, 2000. Collected fragments were said to be some of the purest ever collected, and researchers found that the fragments contained an assortment of organic matter including pyridine carboxylic acids and amino acids, the building blocks of proteins. Constituent parts of life zipping around on comets and asteroids increases the chances of life emerging elsewhere, which is obviously cool because, you know, aliens. But it's also pretty cool—cosmological, really—to consider that life as we know it is already pretty alien to begin with.