If you've been eating an apple a day to keep the doctor away but haven't been consuming the core, you are likely missing out on some of the most beneficially nutritious parts of the apple.
That's according to a new study conducted by researchers at Graz University of Technology in Austria.
In addition to fiber and flavonoids, apples contain bacteria (the good, gut-healthy kind) and most of that bacteria is found in the fruit's core, stem, seeds and all.
According to the study, which was published this month in the journal Frontiers of Microbiology, found that a single apple contains about 100 million bacterial cells — but if you toss out the core, you're only consuming about 10 million of these precious cells.
"Overall, stem and seeds showed highest bacterial abundance, followed by calyx end, stem end and fruit pulp; peel microbiota were lowest abundant," the study states.
The majority of the 100 million microbes in the human body live in our gut, particularly the large intestine. Of these gut flora, there are both good and bad ones.
The good flora are incredibly important for healthy bodily functions: they "help digest our food, regulate our immune system, protect against other bacteria that cause disease, and produce vitamins including B vitamins B12, thiamine and riboflavin, and Vitamin K, which is needed for blood coagulation," according to The Center for Ecogenetics and Environmental Health at the University of Washington.
Good bacteria can be destroyed by antibiotics or other drug therapies, colonics and diarrhea, which is why it's beneficial to eat foods that feed the healthy bacteria in your gut, like yogurt or whole apples.
The study also found organic apples to have an edge over conventionally grown ones when it comes to bacteria diversity. "Freshly harvested, organically managed apples harbor a significantly more diverse, more even and distinct bacterial community, compared to conventional ones," professor Gabriele Berg, the study's senior author, said in a press release.
Berg continues, "This variety and balance would be expected to limit overgrowth of any one species [of bacteria], and previous studies have reported a negative correlation between human pathogen abundance and microbiome diversity of fresh produce."
While the researchers' results suggest its advantageous to consume the entire apple, many people believe that it's dangerous to eat the seeds of many fruits — including apples — because they contain cyanide. While this is technically true, the reality is a bit more complicated.
Apple seeds (along with cherry and pear seeds) contain a small amount of a compound called amygdalin, which, when metabolized in the digestive system, degrades into highly poisonous hydrogen cyanide, a substance that's lethal in large doses.
This might sound grim, but to put it in perspective, the seeds first have to be crushed or chewed. Secondly, apple seeds contain such a small amount of the potentially harmful chemical that you would likely have to consume hundreds seeds to be at risk of poisoning.
Frances Largeman-Roth, RDN, told TODAY Food that "eating the occasional apple core is not a big deal from a safety standpoint." However, she added, "It's also probably not going to magically heal your gut."
In her opinion, eating the core is relatively harmless but it does have the added benefit of potentially cutting down on food waste. She did not advise eating a bunch of apple cores at once, though. The National Capital Poison Center advises people eating seed-containing fruits to proceed cautiously.
"People panic about swallowing fruit seeds or pits because they are known to naturally contain cyanide. Truth is, poisoning from unintentional ingestion of a few pits or seeds is unlikely. Still, ingestion should be avoided. Seeds and pits should never be crushed or placed in a blender for consumption," according to Poison Control.
However, if you're really concerned about poisoning danger (or eat a lot of apples), eating the seeds to get the beneficial bacteria may not be worth it. Bonnie Taub-Dix, RDN, creator of BetterThanDieting.com, and author of "Read It Before You Eat It - Taking You from Label to Table," told TODAY that there are plenty of other ways to get healthy bacteria into your gut
"Although there may be some gut health benefits from eating apple seeds [and fiber], the risks of consuming them may out weigh their benefits," Taub-Dix said via email. "There are so many other foods that have been shown to enhance gut health and fuel bacteria, so why eat something that could do more harm than good?"
She recommended adding foods like kefir, kimchi and yogurt "before resorting to apple seeds." However, she does advise eating everything else — peel, core and flesh — to make the most of the apple's nutrition.
If consuming apple seeds doesn't concern you since the risk of poisoning is very unlikely, but you're wondering how to actually eat an apple core, a video published by The Atlantic shows the core is just a "myth" and all you have to do is bite from the bottom of the apple towards the top to easily consume the entire fruit.