There are so many foods and substances that people can be allergic to; peanuts, cows' milk, eggs, pollen, or animals. Even mangoes or bananas.

We are so much more aware of allergies now but there is also evidence that more people than ever have allergies. BBC journalist Frances Mao talks us through what allergies are - and why more of us are suffering with allergies. She also tells us about some new treatments being tested to treat them.

Australia is now described as the allergy capital of the world. Frances (who grew up in Australia) explains why. And Professor Kirsten Perrett, Director of the Australian National Allergy Centre of Excellence, tells us about the role of Vitamin D.

If you’ve got a serious allergy, it can be really stressful managing it and making sure the stuff you eat and come into contact with isn’t going to harm you. We hear from Mia Silverman (@AllergieswithMia) who is based in the US and allergic to 50 different food types.

And Maria Clara from the What in the World team tells us what it’s like to have immunotherapy for an allergy.

Instagram: @bbcwhatintheworld Email: whatintheworld@bbc.co.uk WhatsApp: +44 0330 12 33 22 6 Presenter: Hannah Gelbart Producers: Julia Ross-Roy and Maria Clara Montoya Video journalist: Baldeep Chahal Editor: Verity Wilde