You might associate “microbes” with germs, but they aren’t all nasty things that make you sick. In fact, some of them are very helpful.

Your body is an amazingly complex group of systems working together, but there are things your body can’t do on its own. You have about 372 trillion cells, but 90% are actually microbial cells. For many it’s a symbiotic relationship: you provide free food and board, and the microorganisms do the things you can’t.

Unfortunately, every now and then, even the good microbes can take advantage of your hospitality and make you sick. The trick is to look after them, so I’m going to introduce you to a few of your houseguests, and tell you a bit about how to take care of them.

Malassezia furfur

Malassezia furfur is part of the only family of fungi to live on your skin without causing disease. M. furfur and its cousins eat lipids, so you can find it on any oily part of your body, especially your face and upper torso.

If you remember from biology, all plants and fungi have a cell wall on the outside of their membranes. For M. furfur, a lot of that is made of lipids (oils), which is very unusual. But it needs those lipids, because it uses them as an invisibility cloak to stop your immune system getting rid of it.

Meanwhile, it’s also stopping you from getting skin cancer. We actually don’t know a lot about M. furfur, because it’s really hard to grow in the lab, but scientists think it does way more too.

Problems and causes: M. furfur can cause skin conditions like psoriasis and dandruff. However, that only happens if you’re using a certain chemical a lot.

Sodium lauryl sulfate is a detergent commonly found in many shampoos and soaps. If you use it too much, it can strip the lipids from M. furfur’s cell wall. When that happens, the invisibility cloak is lifted.

When your immune system sees M. furfur, it launches an attack, causing inflammation – and a painful and horrible-looking skin condition.

What you can do: Wash your face with water only. You might want to do this at least twice a day, at morning and night, and after exercise (that can help with acne too!). You can keep your shampoo and bodywash, just only use as much as you need.

Escherichia coli

You might know Escherichia coli as the evil E. coli, but this bacteria usually lives happily in your stomach, helping you to make vitamin K, which is essential for blood clotting.

Problems and causes: Only the pathogenic strains that produce Shiga toxin are harmful, but they can cause vomiting, bloody diarrhoea, and extreme stomach cramps. In some cases, it can kill you by shutting down your kidneys.

What you can do: Eat a balanced diet, and try naturally probiotic foods like yoghurt, which can help all of the microbes in your stomach. Avoid the pathogenic E. coli strains by practicing food safety: cook well, always keep food covered, and put it in the fridge if it’s not going to be eaten straight away.

Heliobacter pylori

Heliobacter pylori stops you from developing asthma and allergies. It usually lives in the mucous layers of your stomach, where it trains your immune system, stopping it from attacking you or things that aren’t threats (like food proteins).

Problems and causes: Unfortunately, only 50% of the population have H. pylori. This is because lots of kids are growing up in environments that are too clean. When it is around, there have been links to stomach ulcers and even cancers.

What you can do: First things first: get dirty! Abide by the three-second rule if you drop food on the floor in your house, and don’t bother with hand sanitiser as a general rule.

But you still have to wash your hands properly and shower and clean the kitchen bench. If you don’t go overboard on “clean”, you’ll attract all the right microbes and avoiding the not-so-good.

You’ll also need to eat a balanced diet: specifically, fruit and vegetables, and ease up on the salt. That will keep H. pylori alive, without causing any problems.

To recap, there are millions of species of microbes living in and on your body, and they’re there to help you. But you have to look after them. You can:

  • Eat a balanced diet. Try eating more fruit and veggies, more yoghurt and other naturally probiotic foods, and less salt. You’ll soon figure out which foods make you and your microbes feel healthiest.
  • Use antibiotics responsibly. They ONLY work for bacterial infections, and must be taken to the end of the course. If you don’t take them all, or take them when you don’t need them, you are helping to make superbugs that are immune to antibiotics, and could kill you. Eat probiotic foods too, and you’ll be 100% in no time.
  • Be clean, but don’t go overboard. Soaps and antibacterials can kill your good microbes if used too often.
  • Cook, cover, cool foods, always.