IT IS that time of year again. The days are brighter, daffodils start popping up around my neighbourhood, the dawn chorus of birdsong finally returns each morning and my social media starts filling up with anxious questions about whether local honey can treat hay fever. Now, I realise this is a little self-interested, but here is my attempt to get to the bottom of the best evidence we have to date, once and for all. Or at least until more studies come in.

With approximately 20 per cent of people in the UK affected by an allergic response to airborne pollen, it is perhaps unsurprising that many are turning to an everyday food that contains small amounts of pollen, but doesn’t trigger the allergy, as a plausible-sounding remedy. Being great-tasting, widely available and relatively inexpensive, honey would indeed be an excellent vehicle to administer non-triggering doses of pollen. This is supposed to work as a form of immunotherapy to prime our bodies to deal with the summer onslaught. When you consider the potential side effects of the antihistamines used in conventional medication, you can definitely see the allure. But what does the evidence actually say?

Despite the frequency with which local honey’s therapeutic effect is claimed, there seem to only be three scientific studies that have systematically investigated it. Sadly none of them, arguably, in a particularly robust way.

The most recent one is a 2013 study carried out in West Malaysia. This found that after consuming a multifloral honey produced by a tropical bee species deep in the rainforest for four weeks, people showed an improvement in symptoms for allergic rhinitis, which continued to the end of the eight-week study and beyond. PDFs of the report are often sent to me by people from the UK and US as “proof” that local honey is indeed a cure for hay fever.

The first thing that piqued my interest as a Malaysian botanist coming across this study is that hay fever is essentially unknown in the humid tropics. In the equatorial climate, plants don’t release pollen en masse in the same short windows that they do in highly seasonal, temperate regions. Indeed, when you look at the methodology of the study, it didn’t even look at hay fever at all, but at other allergies to dust and pets.

Even if it did, is a rare honey from a rainforest bee comparable with that of European honeybees foraging on totally different plants for people in the UK and US? Can this Malaysian honey even be described as local to the participants in the study, who didn’t live in the heart of rainforest reserves, let alone to people on the other side of the planet?

“They didn’t track the weight of the participants after the addition of more than 10,000 calories during the study”

Finally, let’s look at the dose of 1 gram per kilogram of body weight used in the study. For me, that’s 90 grams of honey per day, which is three times the maximum daily amount of sugar the National Health Service in England recommends I consume. I note the researchers didn’t track the weight or blood sugar levels of the participants after the addition of more than 10,000 calories from sugar during the study.

What about the other studies? A few years before the Malaysian trial, a team in Finland reported that people consuming birch pollen honey had “significantly better control of their symptoms than those on conventional medication only”. But birch trees are pollinated by wind, not by bees, so what is birch pollen honey? The answer is honey with added pollen. So, again, is this a like-for-like comparison?

The only other study is from 2002 from the University of Connecticut, which appears to be the best-designed of the three to test the claim of whether ordinary honey consumption can improve hay fever symptoms, by people consuming one tablespoon of honey per day, and found no significant difference.

It is important to point out that in the latter two trials all the participants were given honey on top of the existing antihistamines they were taking. So whatever the result, the idea that honey is a more (or less) effective alternative to these medications can’t be established as there was no side-by-side comparison. Furthermore, all the trials were very short term and tested really small groups of people, so much more evidence is needed to authoritatively confirm or negate this claim.

What we can say, however, is that the bold statements we often see simply aren’t supported by solid evidence at this time. Indeed, when we look at the alleged mechanism of action behind this claim, it seems increasingly shaky, because the vast majority of people with hay fever are allergic to tree and grass pollen, not those from insect-pollinated flowers, which are what are used to make honey. So, for now, I am afraid this online fact should probably be confined to the fiction pile.