Shadow puppetry can be beautiful to look at, but when it’s happening inside our eyeballs, it’s an annoyance. One of the banes of getting older is the appearance of apparitions in our vision. In Latin, they are known as muscae volitantes. In French, they translate as flying flies. We know them in English as floaters.
You may be familiar with them. These translucent shapes drift in front of our eyes like they are sliding on a slick puddle of oil. They are worm-like threads or spots or bits of cobweb, slowly sliding up and down, left and right, marring a once crystalline vision with ever-moving debris.
It would be wonderful if they could be eliminated simply by eating more pineapple.
This is the rather juicy claim made in a video boldly titled “Eye Floaters No More!” that has garnered 1.7 million views on YouTube. The video itself contains a number of caveats, but you wouldn’t know it from the clickbaity title. Others have made videos taking on the dietary challenge to see if their floaters have disappeared.
Before we take a closer look at the role pineapples may play in clearing the cobwebs in the old optical space, a word on what floaters actually are.
There’s always room inside the eye for Jell-O
Eyeballs are squishy and many people recoil at the sight of them being poked and prodded. But if we were to be shrunk and take a trip inside one of them, we would be swimming in what is called the vitreous, short for vitreous humour.
You can imagine this vitreous inside of your eye as a ball of Jell-O with tiny hairs inside. Those are the proteins, including collagen. As we get older, the gel and the hairs begin to separate here and there. These tiny hairs, the collagen fibres, start to clump up, creating thick cables, leaving behind pockets in the gel devoid of proteins. These pockets are basically liquid water. In this way, the vitreous is said to shrink.
Eventually, some of these collagen cables make their way back inside the liquid pockets and move around. Light enters the eye and is partially blocked by these collagen bundles, casting a shadow on the retina. This is how we see them, drifting as if they are sliding on wet ice.
When floaters appear suddenly, especially if they are accompanied by flashing lights, it could very well be a sign that the retina at the back of the eye (responsible for translating light into an electrical signal our brain interprets as images) is detaching. An ophthalmologist is urgently needed. But when floaters gradually appear, they are often due to this age-related process of our eyeball Jell-O changing and collagen cables floating around in liquid pockets. It’s not a problem in and of itself, but it can be annoying and, in extreme cases, can impair vision enough that a treatment is sought.
How about pineapples, then?
Dr. Pineapple will see you now
The idea that eating more pineapple could get rid of eye floaters comes from a study out of Taiwan published in 2019. It is a pilot study with no control group that includes such unusual English-language sentences as, “The famous, beneficial and delicious pineapples were supplied by the local farmers selling to the world since 1900.”
In short, the researchers conducted two experiments. In the first, 190 participants with floaters ate two pieces of pineapple after lunch each day for three months. In the second, 198 participants with floaters were randomly assigned to one of three groups. Group 1 ate one piece of pineapple a day; Group 2, two pieces; Group 3, three pieces. Everybody had their eyes examined every month. After three months, a substantial percentage of participants had fewer floaters, we are told.
Why were pineapples chosen in the first place? Because the tropical fruit contains an enzyme called bromelain. In fact, the word “bromelain” can refer to one of two enzymes found in pineapple, the combination of the two, or even an extract that also contains other enzymes called comosain and ananain. The bottom line is that, in nature, certain enzymes act like Pac-Man: they break longer molecules into small building blocks. They digest them. Bromelain can digest proteins, specifically collagen, and eye floaters are made of collagen. Ergo, the researchers thought, maybe eating pineapple chunks daily would allow the bromelain to digest the floaters.
As an aside, this is why you can’t use fresh pineapple while making Jell-O: the bromelain in the pineapple will digest the collagen that the Jell-O needs to set. Canned pineapple is OK, because the heat treatment used in canning inactivates bromelain.
The Taiwanese pilot study is far from definitive. Its biggest limitation is that there was no control group of people with floaters who did not eat pineapple. Indeed, not only do people typically get used to floaters, noticing them much less frequently, but the floaters themselves can settle below the visual axis. Not having a control group means we do not know what would have naturally happened without the pineapple supplementation.
We do not even know if the bromelain found inside fresh pineapple can indeed end up in the vitreous and in what quantities. And if it does, why would it selectively chew up the floaters and not the collagen naturally dissolved in the vitreous?
The lead researcher, Chi-Ting Horng, followed up his pilot study with two more: a test of a supplement containing bromelain and two other enzymes in humans with floaters, and an animal study of pineapple in mice or rats (the paper uses the words as synonyms even though they are not). The animal study is very small, but the supplement study in humans is interesting in that it includes a group of participants who did not take this supplement. From a starting point of 40 people with floaters in each group, the researchers saw, three months later, 38 with floaters in the control group (no supplement), 14 in those taking one capsule a day, 12 in those taking two, and 10 in those taking three. Bold results, and I would like to see them independently replicated. I am also puzzled by something: if the bromelain really is this effective against the collagen freely floating inside our eyeballs, what is it doing to the collagen elsewhere in our body? This was not investigated.
There are medical treatments for particularly bothersome floaters—involving surgery and lasers, with some bromelain-like drugs being in the experimental stage—but they are not without their potential complications. So eating more pineapple seems like a harmless alternative.
Some people will want to add more pineapple to their daily diet, though a few qualifications. Pineapple allergy is real, and people allergic to latex, wheat, celery, papain, carrot, fennel, cypress pollen, or grass pollen may also be allergic to the bromelain found in pineapple. Canned pineapple and pineapple juice have had their bromelain inactivated by heat treatment, so fresh pineapple is the only one that would work, if we are to trust the Taiwanese results. And then there’s the sugar content. Study participants ate between 100 and 300 grams of pineapple every day for three months. That’s roughly 10 to 30 grams of sugar a day from pineapple alone, which is a lot. The researchers themselves were aware of this, stating that eating too much pineapple would be harmful to patients with diabetes as it may elevate glucose levels in the blood.
Bromelain is also available as a supplement, removed from all that sugar. Because supplements are approved by a looser process than the one overseeing pharmaceuticals, adulteration and contamination are not infrequent. Buyer beware. Bromelain may also interact with antibiotics and blood thinners. And, in the interest of providing an alternate explanation to any positive anecdote you may throw my way, keep in mind that most people get used to floaters over time and stop noticing them as frequently. If floaters are a new phenomenon for you and you start taking bromelain supplements, you may believe the number of floaters is going down, but it may simply be that you stop noticing them as often. Your wallet, however, won’t see the difference.
One thing bromelain is clearly good at, though, is tenderizing meat: the toughness of a steak can be due to collagen, and bromelain chews it up for you. Whether or not it can chew up, Pac-Man style, the collagen floaters in the Jell-O of our eyeballs—"eye floaters no more,” as the YouTube video claimed—remains to be replicated. My floaters and I are still hungry for better evidence.
-Eye floaters are bundles of collagen fibres that drift in liquid pockets inside our eyeballs and they tend to become more common with age
-Fresh pineapple contains enzymes collectively known as bromelain that can digest collagen
-Three small Taiwanese studies, one in rodents and two in humans, provide very preliminary evidence that eating pineapple every day or taking a bromelain supplement daily may help get rid of floaters, although the studies were small, one lacked a control group, and there are potential harms to this regimen that need to be taken into consideration