Category Archives: Science

Oral Allergy Syndrome – When Fruit Turns Nasty

Oral Allergy Syndrome - Fruit Onslaught
© Tessa Cheung

Some who know me have remarked that I seem to like collecting rare health conditions. Sometimes I find it hard to argue, what with being unable to burp and also suffering from a myriad of allergies. Allergies are very commonplace in developed countries nowadays, but after becoming allergic to more and more fruits (and some raw vegetables) that I used to eat frequently, I decided to dig for information and found out that I have oral allergy syndrome. The condition is surprisingly not that well known, even though there is a fair amount of information about it now; a doctor I asked said that she’d never heard of it.

What the Heck is Oral Allergy Syndrome?

Oral allergy syndrome (OAS) is a result of cross-reactivity in hayfever sufferers. Allergies are caused by the body’s immune system producing an unnecessary response to normally non-harmful substances – in the case of hayfever, pollen. The immune response leads to itching and swelling in the areas exposed to the pollen, and hayfever sufferers will be all too familiar with the results: streaming eyes, endless sneezing and general misery. The protein structures of certain pollens are similar to the proteins found in various fruits, vegetables, nuts and spices, and if the immune system also recognises these as “hostile” then allergic reactions can also occur when these are eaten. These reactions tend to be limited to areas that have been directly exposed, and most often the mucus membranes of the mouth are affected – hence the term, “oral allergy syndrome”, although it is also known as pollen-food syndrome (PFS). Symptoms include itching, tingling and sometimes swelling in the lips, mouth and throat. Nausea may also occur after eating the offending item, which goes away after the stomach juices have had enough time to break down the proteins.

The types of foods which may cause a reaction depend on which pollen allergy or allergies you have. The American Academy of Allergy, Asthma and Immunology (AAAAI) website has an brilliant table documenting what you can expect to react to if you’re allergic to birch, grass, ragweed or mugwort pollen. You can find out which one you’re allergic to through allergy testing at a clinic (in the UK this usually involves seeing your GP first for a referral to a hospital clinic). If you’re allergic to something in a particular family, you can often predict that you should avoid others in that family. For example: apples, pears, quinces, apricots, plums, cherries, peaches, raspberries, loquats, strawberries and almonds are all in the Rosaceae (or rose) family, any of which you might react to if you suffer from a birch pollen allergy.

Living with Oral Allergy Syndrome

OAS is caused by eating raw fruits and vegetables. This is because the food proteins are in their immune response-activating state when uncooked. Proteins are altered in shape, or denatured, by heat, pH changes, radiation, exposure to oxygen and mechanical agitation. After this occurs, the immune system does not recognise the proteins.

Protein denaturation

Ways you could continue to eat fruits and vegetables, as recommended by Allergy UK, include:

  • Cooking them – the heat distorts the proteins.
  • Peeling them – the proteins are often concentrated in the skin.
  • Microwaving them – this does not need to be done for so long that the fruit/veg is fully cooked, just long enough that most of it has been exposed to microwaves. In my experience 15 seconds is long enough for a small chopped and peeled apple. I actually got a nifty device that peels, cores and cuts apples into a spiral, making them much faster to prepare. I do miss the days when all I had to do was wash them.
  • Trying a different variety – you may find that you are allergic to some varieties of apples but not others, for example. You shouldn’t try this if you suffer from severe reactions to a particular fruit/vegetable/nut/spice, however – it would be better to avoid completely.

Other preparation methods that have worked for me include:

  • Cutting them up or juicing, and then leaving them in the fridge for about 6-8 hours or longer – this exposes the insides of the produce to oxygen, which begins the degradation of the fruit. It also activates enzymes that are present, some of which cause deterioration. Juicing fruit may cause denaturation mechanically as well.
  • Freezing them – this has worked for me with blueberries. I’m guessing that the water in the cells of the fruit forms ice crystals, which disrupts the protein structures.

Frozen blueberries

  • Drying them – the dried versions of some offending fruits such as apples, blueberries and figs haven’t caused any reaction for me thus far. This may be because some of them are dried using heat.

Dried appleUnfortunately cooking, juicing and cutting fresh fruits and vegetables does reduce the nutritional content as some vitamins are oxygen and heat sensitive. Resorting to the above methods is better than not eating them at all though, as they still retain some nutrients. You can’t use OAS as an excuse to cut them all out of your diet I’m afraid! During the height of hayfever season you might want to avoid the problem foods altogether though, as the reaction can be worse at this time.

If you have a reaction to nuts, a widespread reaction such as a rash or breathing problems or react even to cooked products then make sure to consult a doctor.

Hopefully this has taken some of the mysticism out of oral allergy syndrome. Now face those fruits!

I Can’t Burp – The Illustrated Guide

Last year I wrote a post about dysfunction of the burp reflex. Looking back on it now, I can see that it’s pretty wordy. Those who mock or doubt the condition would be especially put off from reading so many sentences about those who can’t burp (and it is they in particular who should read it!). Therefore I decided to create:

Can't burp title page

Since I’m an illustrator and all.

DBR - stomach


burp diagram


can't burp - dysfunction of burp reflex

I understand that this is still fairly wordy – some words were still necessary. Hopefully it has helped to explain this much dismissed (and bloody annoying) condition more clearly.

More illustrations about the condition, what can help and why to follow!

Virtual Reality Sight Saver – Vivid Vision

Courtesy of Vivid VisionVirtual reality in gaming is coming soon: the Oculus Rift headset will finally be available to the general public next year. As it became clear that it really was a viable product and not just a pie in the sky, companies and individuals could imagine the potential of seeing in stereo with this sort of device.

One such individual is James Blaha, the co-founder and CEO of Vivid Vision. He suffered from both amblyopia – commonly known as lazy eye – and strabismus, where the eye turns inwards. He considered possible treatments, such as transmitting separate images to each eye using two projectors to strengthen the weaker one. When Oculus Rift became available, he realised that it was the technology he needed.

James Blaha. Courtesy of Vivid Vision
James Blaha, co-founder and CEO of Vivid Vision

Experimenting on his own vision, he and co-founder Manish Gupta developed a game called ‘Diplopia’ which uses the Oculus Rift system to project different images to each eye. Since a hugely successful Indiegogo campaign in 2013, they have included motion detection using Leap Motion to make it more interactive. Using his software, Blaha gained 80% stereo vision and now has almost 20/20 vision when wearing his glasses. A small Slovakian trial also saw improvement in 9 out of 15 participants.

Vivid Vision’s optometrist advisor, Tuan Tran, explains the basics behind how the treatment works:

Vivid works by using a virtual reality device that goes on your head, which is similar to a pair of glasses. We are able to control what the left and right eye sees. [If] the left eye has a turn, we would be able to cast the image so it displays at your deviation. As you get better, the deviation will decrease until your eyes are essentially straight … So once we have all this calibrated, you will then play a game. Let’s pretend it’s tennis. Both eyes will see the arena and the net. The good eye will see the tennis racquet while the lazy eye will see the ball. This encourages the brain to use both eyes together, otherwise you will not see the ball!

This software may see an end to embarrassing eye patch therapy, where the stronger eye is covered or fogged over with a special lense to force the weaker one to adapt. Playing games using gestures will also be much more fun than traditional vision therapy, where compliance is an issue. The most important breakthrough though is the possibility to treat older patients with lazy eye – over the age of eight, the chance of successful treatment drops. Blaha reports that improvements have been seen in Vivid Vision users in their 50’s and 60’s. Even better, once vision has improved the software may not need to be used at all. “In my experience you don’t need to keep using the software to keep it up,” Blaha informed a participant of their Reddit Ask Me Anything session in June. “It is kind of like an atrophied muscle, once it is strong enough for daily use that should be enough.”

There are plans to expand Vivid Vision services to the UK, and several eye clinics have expressed interest in the system. The Vivid Vision software will be available when Oculus Rift is – currently slated as the first quarter of 2016.

Iodine Supplements in Pregnancy

Taking iodine supplements whilst pregnant may be a cost effective from a long term health perspective, researchers from the University of Birmingham have found.

Iodine crystals

Previous studies have shown that even a mild lack of iodine can affect the intellectual development of children, measured by intelligence quotient (IQ) scores. Neurological disorders can also occur if the mother is severely deficient.

The research team analysed the data from many different studies looking at IQ scores and income. It took into account the costs that result from iodine deficiency, such as education and healthcare, and compared these with the required investment for iodine supplements. The conclusion was that providing supplements would lead to an increase of 1.22 IQ points per child and £3,297 of lifetime earnings, and a saving to society of £4,476 per pregnant woman.

Iodine in Pregnancy

Iodine in pregnancy - pregnant belly_with pills

The recommended daily amount of iodine for adults is 150mcg. During pregnancy, it is 250mcg (the same for breastfeeding women). Because it is important for mental development of the unborn baby, it’s a good idea to start taking supplements or ensuring there is enough iodine in the diet before becoming pregnant.

Foods rich in iodine include seafood (white fish, oily fish, shellfish) and dairy (milk, yoghurt). Seaweed is especially rich in it, but because of the high content may contain too much. It is recommended that pregnant women not eat more seaweed more than once a week.

Pregnant women who are concerned about their iodine levels should consult their doctor before taking supplements, as the amount in them may vary and can lead to over consumption. Those thyroid problems should make sure that they speak to their doctor before making any changes to their iodine intake.

This fact sheet from the Association of British Dietitians contains more information about iodine in pregnancy.

The Science Behind Vampires: Bloody Diets

Shiki. Daume, BS Fuji.

I recently finished the gripping and disturbing anime series ‘Shiki’, which features vampire-like beings. I’d recommend it to those who like their entertainment bloody and thought provoking (and full of really bizarre hairdos).

One thought it provoked in me was whether it is feasible to live off blood alone. A few months ago I was reading the Q&A section on the BBC Science Focus site, where people can ask weird and wonderful things for some science boffin to answer, and this particular question was asked. The basic answer is that it isn’t possible, since we wouldn’t be able to extract water from it – because it has the same water and salt content as our own blood, there is no osmotic gradient to cause the water to move into the bloodstream – and it’s also too salty for us. Dehydration and kidney failure would quickly dispatch any wannabe vampire. The rich iron content could also prove toxic, although the author of the article states that 26 litres of blood would have to be imbibed per day to bring about iron poisoning. So obligatory hematophagy, or just eating blood, is not a possibility for humans.

What would it take to be able to live off blood then, and what adaptations would vampires need if they were a real life species? The best way to consider this is to look at existing examples.

Continue reading The Science Behind Vampires: Bloody Diets

The Drinkable Book: Saving Lives, Page by Page

I’ve only just discovered an incredible, lifesaving invention: the Drinkable Book. It was invented by Dr. Theresa Dankovich, who came up with the idea for her PhD research project at McGill University in Montreal.

It sounds deceptively simple – a piece of paper infused with silver nanoparticles, which costs pennies to produce. The silver particles in the “coffee filter”-like paper have been found to reduce the bacterial content of contaminated water by 99.9%, making it comparable to our tap water. A user simply has to tear half a page out of the book, place it into the filter box (which is also the case for the book) and pour the water through. The filtered water comes through the paper and ends up in the bottom of the box, ready to drink.

This isn’t all. As a major reason for deaths from dirty drinking water was found to stem from a lack of knowledge about what causes the problem, the paper has doubled as an educational tool. Edible inks have been used to print the whys and hows of water sanitation, explaining in simple terms how to keep water clean.

The product is still being tested and refined, with input from the communities that will end up using it. An attempt was made to crowdfund the project last year, and although it raised over $11,000 it fell short of the $20,000 target. A new crowdfunding campaign started two days ago with a goal of $30,000. If you would like to support the project, you can do so by visiting their Indiegogo page.

Grow Your Own: How Artificial Organs Will Change the Face of Medicine

Back in June I entered the University of the West of England and BBC Focus Magazine’s science writing competition, which had the theme “the Science that will transform our future”. I didn’t win anything of course, but thought I’d share the article. You can read the winners’ entries here.

Grow Your Own: How Artificial Organs Will Change the Face of Medicine

A human ear growing out of the back of a mouse. In 1997 this astonishing image led to speculation that one day organs for human transplantation might be obtained this way. Since then the field of body part and organ creation has seen real progress, and the new direction it has taken appears to bring us much closer to a future where organ donors and animal testing are obsolete.

Continue reading Grow Your Own: How Artificial Organs Will Change the Face of Medicine