What to do about allergies?

By Sophie Medlin (Former Lecturer in Nutrition and Dietetics, King's College London)

Some people are allergic to substances in the air, such as pollen, dust, and animal fur. Others are allergic to specific foods, like nuts, for example.


When we are allergic to something, our body mistakenly thinks it will harm us.

The immune system (which normally fights infections) then starts to attack the substance to which we are allergic, resulting in symptoms that are signs something is wrong in our body.

These symptoms can range from nasal itching and sneezing to breathing problems or a skin rash. In the case of severe allergies, the tongue or throat may swell, which can be very dangerous.

Some allergies can be very severe

There are very severe allergies that require extreme caution because they can lead to a very serious medical problem called anaphylaxis.

The most common foods causing anaphylaxis are nuts and eggs. People with these allergies should always carry a special product that can be injected in case they accidentally consume these foods, and they must always be very cautious around food.

Certain less severe allergies, such as hay fever, might improve if you were stranded on an island for a long time without any medication. Indeed, our body may get used to the pollen causing this allergy.

Medical methods exist to test this hypothesis, what experts call "desensitization therapy" or "immunotherapy." This means you receive a certain amount of the allergenic substance each day until you become less sensitive to it. This treatment must always be done with the help of a doctor and it does not work for all allergies.

Intolerance is not allergy

There are substances to which you may be intolerant, but not allergic. This means that eating them might cause stomach problems, but it won't cause severe damage.


Milk is a prime example. It contains a type of sugar called lactose. Humans need a special chemical substance called an enzyme to digest lactose, which is made in our intestines.

When we are babies, we all produce a lot of this enzyme because we only drink milk. As adults, some people stop producing this enzyme altogether, while others produce it less. Still, others might produce it variably depending on how much milk they drink.

This means that sometimes, if you haven't drunk much milk for a while and then consume a lot, you might get a stomach ache. But it could also be that the more milk you drink, the more enzymes your intestine produces, allowing you to drink more milk without discomfort.

Only milk from animal sources (including human milk) contains lactose. Plant-based "milks," like coconut, soy, and almond milk, do not contain lactose.

Whether you suffer from an allergy or an intolerance, it's very important to always follow your doctor's advice.