Inflammation: the fire that never goes out

Cut your finger and the area goes red, warm and sore. That is inflammation doing exactly what it should: arriving, dealing with the problem, and then stopping. Without it nothing would heal.

The other kind is not like that at all. It is low-level, it produces no redness or pain you can point to, and it does not switch off. Think of a fire that never quite goes out, smouldering away for years.

Long-running inflammation turns up in the story of heart disease, type 2 diabetes, arthritis and dementia risk. That is why those subjects keep overlapping rather than being separate compartments.

It is also part of why one problem tends to bring others. Somebody with diabetes, extra weight round the middle and poor sleep is not unlucky three times over; the three share a good deal of the same machinery.

Fat carried around the organs is itself active, sending out inflammatory signals. So are smoking, long-running stress, broken sleep, sitting most of the day, and a diet heavy in refined carbohydrate and deep-fried food.

Gum disease belongs on this list too, which is why teeth are not a separate subject from the rest of your health.

Nothing exotic, which is either disappointing or encouraging depending on your mood. Regular movement, keeping muscle, sleeping properly, plenty of fibre and colourful vegetables, sensible oils, less packaged food, and taking stress seriously.

Working muscle deserves a particular mention, because contracting muscle releases messengers that actively calm inflammation. Exercise is not only burning something off; it is sending a signal.

This is general guidance, not medical advice, and inflammation that shows itself as a hot swollen joint, fever or persistent pain needs a doctor rather than a change of diet.