A slew of recent news stories suggesting that organic apples have way more beneficial bacteria than conventionally-grown apples left us wondering— should we worry about our families missing out on beneficial bacteria if we don’t buy organic apples? That’s the question we’ll address in this installment of “Are We Worried,” in which we take readers through our thinking as we decide how much to worry about the latest scary thing that could affect our kids.
Personally, my first instinct is to be skeptical any time the results of a “new study” dominate the news cycle. Take a story headlined, “100 million apple bacteria actually keep the doctor away: study,” from the New York Post:
“An apple not treated with pesticides contains more than 100 million diverse bacteria could make them better for our health than conventional apples, according to a study published Wednesday in the journal Frontiers in Microbiology.
These millions of microbes are important in maintaining a healthy gut environment, which other research has linked to everything from lowering our risk of developing allergies to better mental health.”
Some reports, like this one from CBS New York, suggested that “we’ve been eating apples all wrong” because the study “says the core and stem contain the highest concentration of the good, gut health-promoting bacteria usually called probiotics.”
But I have questions:
Did the study look at whether specific pesticides impacted the composition of microbes on and in apples?
The study doesn’t contain the word pesticides, not even once. It’s a huge stretch to assume that organic apples aren’t treated with pesticides (organic doesn’t mean pesticide-free).
Where did the apples in the study come from?
In some situations, we SciMoms decide not to worry about news reports on the latest “new study” about our health, even before taking a close look at the study. That’s because it’s simply not feasible to sift through all of the relevant literature every time there’s breathless coverage of a new scientific paper. It’s particularly helpful when there’s a solid analysis in a news outlet that has separated the facts from the hype, but in this case, there isn’t yet a quick debunk of the media puffery available (we’ll update here if this changes). So I opened the study, and read that the researchers looked at four apples from one conventional farm in the state of Styria in southern Austria, and four apples from one organic farm in the same region, all from the same cultivar.
I reached out to experts on Twitter, and a few of them shared their insight.
Elisabeth Bik, microbiologist (and exposer extraordinaire of problematic images in biomedical literature):
It is a fun study, but with only one orchard per group, this is very weak science. It would have been much better if there had been apples from 3 organic and 3 conventional orchards.
— Elisabeth Bik (@MicrobiomDigest) July 30, 2019
She pointed out that, while the study findings could be chalked up to differences in farming practices between organic and conventional orchards, differences in soil, age of trees, how the farmer removes the apples from the trees, and other factors could also have played a role.
Yes, the health of one’s gut environment has been linked to better health, but does the diversity of bacteria found on these specific apples mean that organic apples are going to reduce our risk of allergies or any other condition shown to be linked to a healthy gut microbiome?
Jonathan Eisen, evolutionary biologist and editor-in-chief of PLOS Biology, noted that the article “provides no direct data on any health effect,” and that “the only possible connection is incredibly weak and indirect,” especially because of the tiny number of samples. He went as far as to call a story in The Guardian, which suggested that the bacteria on organic apples “keep the doctor away” a nearly perfect example of what he calls “microbiomania.”
Bik also pointed out that “[T]he paper itself does not appear to claim that the bacteria in apples are beneficial. Those stretch-interpretations are made by some over-enthusiastic news sites.”
Does this really mean that it’s a good idea to eat apple cores on a regular basis?
In a detailed comment on PubPeer, in which she notes that this is a “fun, exploratory study,” Bik explains that, while it may not be the authors’ intention, news stories have wrongly, albeit enthusiastically, extrapolated the study’s findings into claims that “we have been eating apples wrong”, and that eating the seeds would greatly enrich our input of “beneficial bacteria.”
For now, all of this leaves me thinking that there aren’t nearly enough data to conclude that there’s a meaningful difference between the composition of microbial communities on organic and conventional apples, let alone to suggest these differences lead to health disparities.
We’ll continue to focus on making sure that we offer our kids lots of fruits and veggies, since there are plenty of data to support that most Americans don’t eat enough of them, which can harm our health. As noted in our Risk in Perspective series, we humans are intuitively terrible at assessing risk, and in this case, the benefits of eating any apples far outweigh the risk of missing out on certain beneficial bacteria. In other words, we SciMoms hereby endorse offering kids a variety of fruits and vegetables—and, let’s be real, getting them to actually eat them is easier said than done—with whatever mix of conventionally-grown and organic produce works for your family’s preferences and budget. Make sure to always wash produce according to FDA and CDC guidelines, which we cover in detail here. We’ll shelve worrying about fruit microbiomes until there’s more science, and also pass on eating apple cores, which, frankly, sounds yucky anyway.