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Pineapple core, bromelain, and embryo implantation: what the science really says

Pineapple core, bromelain, and embryo implantation: what the science really says

5 min read

When you're trying to conceive, clinical guidelines emphasize the importance of eating well-balanced meals. But some blogs and online forums point to specific foods helping with infertility and reproductive function — one that comes up often is pineapple core.

In this post, we're examining whether eating pineapple core after ovulation helps an embryo implant (thus increasing your chances of conception). The bottom line up front: There's no scientific evidence to show that pineapple core improves reproductive function or helps combat infertility.  

So, where does that leave you? If you're a fan of pineapple, great — keep eating it! But don't have any expectations about its ability to promote pregnancy. And if pineapple isn't your thing, don't stress — you're not missing out on any tried-and-true method to boost your chances of getting pregnant.

Why people think pineapple core helps you get pregnant

The hype around eating pineapple core to promote embryo implantation is tied to one group of enzymes called bromelain.

Bromelain is found in abundance in pineapple, and especially in the pineapple core. (You can also buy bromelain in supplement form.) It's used for an impressively wide range of reasons —  everything from removing dead skin cells from burns to reducing post-operative pain.

Bromelain is touted for its purported anti-inflammatory and anticoagulant properties. There are some reproductive health conditions associated with inflammation (like endometriosis) — inflammation, in turn, is associated with poorer endometrial development, inhibiting embryo implantation. Therefore, some think that anti-inflammatory and anticoagulant meds (also called “blood thinners”) may potentially improve the uterine lining and blood flow to the uterus, and in that way promote the health of an implantation-friendly endometrium. But implantation is a complex biological process that's driven by a whole host of factors other than just the thickness or look of the uterine lining, making it unlikely that anti-inflammatory and anticoagulant agents will be the magic fix to all problems with implantation. There is also a lack of scientific research to support that claim.

There are also some people who believe that eating too much pineapple before ovulation will make the vaginal and cervical pH too acidic for sperm to survive. While it’s true that different pH levels can be more or less sperm-friendly, there is no data to suggest eating pineapple changes vaginal and cervical pH levels.

The data on bromelain, implantation, and chances of conception

Like many other infertility and conception-related myths out there, the actual scientific data we have on whether eating pineapple core or taking bromelain supplements improves your chances of conception is scant. There are no published, peer-reviewed studies on the topic. More specifically, there are no published studies on people consuming pineapple core to support implantation after an embryo transfer during IVF, and no published studies on people consuming pineapple core while attempting to get pregnant without medical intervention.

In a New York Times interview on the subject, Dr. Tomer Singer, a reproductive endocrinologist at Shady Grove Fertility, said, "There’s no evidence in the literature that says consuming pineapple prior to an embryo transfer will improve implantation."

In the absence of actual studies, people likely turn to anecdotal reports or blog posts on websites that sell bromelain supplements and use these sources as stand-ins for science. The problem is, neither of these sources is free of bias, meaning they should be consumed with a critical eye. Therefore, we can’t confidently say that pineapple core improves implantation — and similarly, we can’t confidently say it doesn’t.  

The pros and cons of pineapple core for fertility

While we don’t have any numbers to suggest eating pineapple promotes implantation, eating pineapple isn’t a bad idea for most people. The fruit is high in healthy nutrients like vitamin C and antioxidants, making it a good fruit to have around regardless of whether or not you’re trying to conceive. (In fact, six ounces of pineapple has over 100% of your recommended daily intake of vitamin C!)

There aren’t any clear cons to eating pineapple slices or the core, either, though high levels of bromelain can be dangerous in certain cases. While it’s really hard to ingest dangerously high levels of bromelain from a pineapple itself, bromelain supplements can contain high enough levels that present risk to certain people. Specifically, people on anticoagulant medications or antibiotics like amoxicillin should consult with a doctor before taking bromelain supplements, as there may be important drug-supplement interactions to watch out for.

A deeper dive into the mechanisms behind the myth

The idea that bromelain promotes implantation hinges on two underlying assumptions: that bromelain is a powerful anti-inflammatory and anticoagulant, and that anti-inflammatory and anticoagulant agents promote implantation. But how strong is the science to support each of those assumptions? We dug into the literature, and turns out there isn’t strong evidence suggesting either of those is true.

First off, the anti-inflammatory and anticoagulant properties of bromelain in living humans are unclear. There’s some work on anti-inflammatory effects of bromelain in animals and in human cells studied in the lab, but not much on whether these same effects would be seen in living, breathing humans. In fact, some studies have found that bromelain specifically has opposite effects on blood coagulation when it’s being studied inside of the body rather than outside of the body. Taken together, the jury is still out on bromelain’s efficacy as an anti-inflammatory and anticoagulant.

Second, how true is it that anti-inflammatory and anticoagulant agents promote implantation? Unlike most of the other questions addressed in this post, there actually is some solid data we can look to for guidance here. Some reproductive endocrinologists will suggest their patients use aspirin (an over-the-counter, FDA-approved anticoagulant) while undergoing frozen embryo transfer cycles, with the idea that it can promote healthy endometrial development.

A 2016 review of all published data found no differences in live birth rates or clinical pregnancy rates based on aspirin use. Another review similarly did not find strong, clear effects of anti-inflammatory medications on live birth rates or pregnancy rates among people using assisted reproductive technologies. There’s a chance that these medications might work in some cases and in some people, but generally speaking, there’s little evidence of a general positive effect of them on implantation rates.

What this makes clear is the bromelain-implantation idea is built upon quite the house of cards: two assumptions that have little-to-no science to back them up. This, along with the fact that there isn’t any hard data linking bromelain to reproductive outcomes, makes it impossible to claim that bromelain has beneficial effects.

For a closer look on science-backed things that do affect your chances of conception, check out our guide here. (Spoiler: Things like Mucinex, different sex positions, or fertility crystals do *not* help you get pregnant faster.)

This article was reviewed by Dr. Temeka Zore, a Modern Fertility medical advisor and reproductive endocrinologist at Spring Fertility in San Francisco.

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Talia Shirazi

Talia is a biological anthropology PhD candidate at Penn State, passionate about women's reproductive health and behavioral neuroendocrinology.

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