Do Plant-Based Diets Really Cause These Common Problems?
Q&A: Vegetarian diets and stomach acid, and whether a compound in plant-based “superfoods” could be causing a wide range of health problems.
Welcome back to Rethinking Wellness! In these biweekly Q&A newsletters, I answer audience questions about wellness culture, including whether particular diets are warranted, the truth about supplements and other protocols, how to spot wellness scams, and lots more. You can ask your own question here for a chance to have it answered in an upcoming edition, and some of these Q&As may end up in bonus episodes of the podcast as well.
Just a reminder that these answers are for educational and informational purposes only, and not a substitute for medical or mental-health advice. Although I am a registered dietitian, I’m not your dietitian (unless you happen to be one of my 1:1 clients—hi!—but even then, this email isn’t a session).
This week’s two questions share a similar theme: the notion that plant-based diets, which are often celebrated in wellness culture, might actually be causing some health issues. Generally, my view is that plant-based diets aren’t all they’re cracked up to be in terms of human health. Why? Because in many cases people go on them for disordered and restrictive reasons—and when they do, their well-being suffers. But of course not everyone falls into that category, and I totally respect the ethical, non-diet-culture-related reasons why some people choose not to eat animal products. And sometimes, plant-based diets are blamed for things that just aren’t justified by the science. It’s a tricky tangle of issues, and this week we’ll dig in and try to sort through some of them.
The first question is available to all subscribers (about whether a mostly vegetarian diet leads to low stomach acid), and the second one is for paid subscribers (about whether a compound in plant-based “superfoods” could be causing health problems).
My integrative health practitioner suggested that my (mostly) vegetarian diet might be partially responsible for my gut issues in that it causes low stomach acid (Hypochlorhydria). I am suspicious because I still eat dairy on a daily basis (cheese, milk, yogurt), and I also do eat meat several times a year. I generally go about eating with intuitive eating practices. I have eaten this way for nearly ten years to help minimize my carbon and environmental footprint, and I’ve always believed my diet was “healthy.” I am wondering if there is validity to the idea that vegetarian/vegan diets result in low stomach acid that can cause digestion issues? In some ways this feels like my practitioner blaming me for my gut problems!
—Molly
I totally get your frustration and skepticism about the advice you got from this integrative health practitioner. I was skeptical, too, and I did some digging into the scientific literature. The results may or may not surprise you, depending on your preexisting level of skepticism!
What I found was that there’s not a single randomized controlled trial, or even any other relevant studies, exploring the relationship between a vegetarian diet and stomach acid levels. This claim seems to just be floating out there without any solid evidence.
It’s not clear from your question whether you’ve actually been diagnosed with hypochlorhydria, which is determined through a stomach-acid test. But if you do have it, chances are it’s not because of what you eat. Instead, hypochlorhydria is most often linked to things like H. pylori infection, long-term use of acid-suppressing medications, or certain autoimmune conditions affecting acid production in the stomach.
Despite the lack of sound scientific evidence, many sources on the internet claim that what you eat can cause low stomach acid. These sources are overwhelmingly (and perhaps unsurprisingly) those in alternative, integrative, and functional medicine spaces. In fact, the concept of low stomach acid seems to be somewhat trendy in these spaces, with claims that hypochlorhydria is linked to “leaky gut syndrome” and “chronic candida”—two popular but dubious diagnoses that I’ve covered in previous newsletters and in The Wellness Trap.
Given all this, I’d take the diagnosis of hypochlorhydria with a grain of salt, and seek a second opinion from a conventional gastroenterologist who doesn’t use an integrative/functional medicine approach. That’s not because I think all integrative/functional providers are bad (I know there are some very caring, evidence-based ones out there) or all conventional providers are good (lol, no). But unfortunately there are a lot of dubious claims and spurious cures in alt-med spaces, and I don’t want anyone to waste their time.
Finally, it’s helpful to explore your relationship with food and your body and consider how that might be influencing your gut issues. You mentioned practicing intuitive eating, which is great! But I can't help but wonder if there are any lingering dieting or restrictive tendencies that might be contributing to the problem. Is it possible that you’re still sometimes dieting or restricting what you eat for reasons other than the environmental/ethical ones you mentioned? Are you confident that you’re doing true intuitive eating, or could you be falling into the trap of the “hunger and fullness diet”? Disordered eating can definitely mess with your digestion, so it’s worth examining if there are any patterns to address.
I hope this gives you some food for thought, Molly. I raise these questions not to blame you for your gut problems, but to encourage you to explore all possible angles in the confusing world of “gut health” (where even the term itself is often linked with wellness misinformation). And if you find that your gut issues persist even after working on your relationship with food, there are interventions to try that don’t involve food or diets at all.
Thanks so much for the great question, Molly, and thanks to all the free subscribers for reading! Paid subscribers can stick around for the bonus Q&A, and everyone can ask their own questions for a chance to have them answered in an upcoming newsletter. (Paid subscribers also get early access to podcast episodes—listen to next week’s episode now!)
Fyi: There is the name of a diet book in the next question, in the context of critiquing it.
Oxalates in “Superfoods”
What’s the deal with oxalates? I was recently diagnosed with osteopenia [low bone mineral density that doesn’t quite reach the threshold of osteoporosis], and a trusted health care provider suggested it might be because of too many oxalates in my plant-heavy diet. She recommended the book Toxic Superfoods—and although I haven’t read it yet, everything about this screams hogwash to me. Or is there something to it? And how does one know what the Sam Hill to believe?
—Susan