You know the diseases of later life – heart attacks, strokes, cancer, and dementia. Living well in middle age and beyond is all about delaying these nasty surprises as long as possible. The point is sometimes expressed as ‘health span’ rather than ‘life span’; not how just long you live, but how long you live in good health.
Fortunately, things in your control, like regular exercise, and healthy eating, make a real difference.
Less well known is that these diseases come from the same thing. They come from inflammation.
You already know inflammation. It is the redness and swelling you get when you sprain your ankle or get a thorn in your thumb. It is normal and healthy in the right place. It mobilises proteins and white blood cells to kill intruders like bacteria, and builds new blood vessels and tissues to heal wounds.
Unfortunately, from middle age and beyond, most people have too much (see Age Better). The consequences are serious.
Heart attacks and most strokes happen because cholesterol, a type of animal fat, forms fatty bubbles in the walls of arteries. Cholesterol bubbles are called atherosclerosis. They grow slowly, over decades, until one of them bursts, and blocks its artery. That is what a heart attack or stroke is: an artery blocked by a ruptured cholesterol deposit.
Your body makes cholesterol, so you can’t avoid it – even vegans can’t – and nor would you want to, as all your cell walls are made from it. However, the cholesterol deposits are not passive. The fat doesn’t just sit there like a rubbish tip. It provokes a reaction, like the thorn in your thumb. The bubbles are alive with the proteins and white blood cells of inflammation. Eventually, inflammation wears away the fibrous cap that contains the cholesterol, and disaster follows.
Atherosclerosis is inevitable, even in people with the healthiest lifestyles. What is not inevitable is how fast it develops, and when it ruptures. This is all down to lifestyle choices: exercise, smoking, and diet.
People with the same cholesterol level have very different rates of heart attacks and strokes; in fact, half of all these events happen in people whose levels are normal. Mice bred without inflammatory proteins have much less atherosclerosis than regular mice, regardless of their cholesterol. So the disease is not cholesterol, the disease is what goes with it.
It is a similar story with cancer. Researchers using the first microscopes saw inflammatory white blood cells in slides of breast cancer 150 years ago, and today numerous lines of evidence lead down the same path. Infections cause cancer, as do foreign bodies, and irritants like tobacco; inflammation is the common factor. People who take anti-inflammatory drugs, like aspirin, for a long time, get less of it.
The link with inflammation is so strong some experts call cancer a “wound that does not heal”.
Once it exists, most cancer floats in a bed of inflammation, which governs the way it grows and spreads, particularly to other organs, the final and most deadly phase. The bed of inflammation is such a strong influence it is sometimes called the “other half of the tumour”.
A lot of modern research also ties inflammation to dementia. Dementia means a breakdown in thinking, and is one of the most feared consequences of old age. In simple forms, people forget their address and the date, and in severe forms, people need help with every aspect of daily living.
One of the earliest insights into dementia and inflammation was that people with rheumatoid arthritis get less dementia, apparently because they spend years taking anti-inflammatory drugs. The risk of dementia rises with age, just as inflammation does, and is more common in people who, for whatever reason, have elevated inflammatory proteins in their blood.
There is good evidence that brain degeneration is slowed by certain foods, such as the polyphenols in turmeric and grapes and tea, that block inflammation and scavenge free radicals.
There is so much evidence that links the immune system with brain diseases that a new medical specialty – psychoneuroimmunology – has been born to cover it.
One imperative stands out in staying healthy for as long as possible – deal with inflammation.