Why your defense decreases as you get older | Right away

Our immune system has been tested for weeks by the coronavirus, and older people in particular are victims. As we get older, the immune system works less well. How did this happen? Professor of Immunology Daniel Davis explains.

How does the immune system actually work?

“The immune system protects us from external enemies. In all our organs and tissues, cells that specialize in the detection of pathogens such as viruses patrol. When they encounter you, they destroy the germ.”

“They also remember what this intruder looked like, so that it is detected more quickly in a second attack. A bespoke defense force is ready to destroy the intruder. This makes the immune response faster and more efficient for the second time. Vaccines also work according to this principle of recognition.”

How is it that the immune system of older people works less?

‘We don’t really know enough about it. This is partly due to the fact that the bone marrow is somewhat exhausted. It provides fewer white blood cells, cells that clean up disease-causing viruses and bacteria.”

“The sweet breads also play a role. This is the organ in which many of the immune cells that have just been created have to develop. The sweet bread shrinks with age and therefore works less and less well.”

“More research needs to be done, but it is certain that high-fiber foods are healthy for the microbiome in the gut.”

Daniel Davis, Professor of Immunology

You write in your book about “low-grade inflammation” in the elderly. What are they?

“In the blood of older people there are often many signs of an active immune response without inflammation. This phenomenon is also referred to as “age inflammation.”

“Due to weak inflammation, the immune system is less able to distinguish between germs and the cells and tissues of the body. In addition, low-grade inflammation prevents the immune system from correctly detecting germs it has never seen before.”

“This is also one reason why the immune system of older people works less. But we don’t know everything yet. We need to do more research on this.”

Can we do something ourselves to strengthen our immune system?

‘It’s hard to investigate. There is a study that shows that older people who make tai chi three times a week are better responsive to a flu vaccine. But this was only a very small study. The only thing that all scientists agree on is that chronic stress is bad for the immune system.”

“This is due to the stress hormone cortisol. If this stays high for a long time, the immune system is suppressed. As a result, people who suffer from long-suffering stress are less likely to recover from a wound, react less well to a vaccine and become sicker from a virus.”

What about food?

“There is also more research on this, but it is certain that fiber-rich food is healthy for the microbiome in the gut. These gut bacteria also play a very important role in your immune system.”

Daniel Davis is Professor of Immunology at the University of Manchester and author of the book “Immune. On the role of our immune system in the fight against disease”, edited by Publisher Nieuwezijds.