The trains, schools, offices and crèches are full and the r is back in the month. How can you protect yourself against all the viruses and pathogenic bacteria that circulate? Does it make sense to increase your resistance and how do you do that?

You cannot escape it: in small and in particular poorly ventilated rooms, viruses and bacteria dance around. "A sneeze is a small hurricane," says Harry Wichers, biochemist at Wageningen University. "The bacteria are lying around. It's hard not to come across them. We are attacked by a virus about seven times a day."

Stress, sleep deprivation and poor nutrition as the culprit

Stress, sleep deprivation, poor nutrition and too much alcohol can make it difficult for the immune system and your resistance to decline. That is also possible due to the autumn and winter that are coming. "Soon we will all be much more indoors and the days will be shorter. Around Christmas almost everyone has a vitamin D deficiency," says Wichers.

About 400,000 people had flu last winter. That is more than half less than in the winter before, reports the National Institute for Public Health and the Environment (RIVM) in the annual report on infectious diseases.

Fighting the flu is difficult

Can you guard against such a flu or a severe cold? According to Wichers that is difficult. "You can ensure that your immune system works as well as possible," he says. "This system of organs, cells and molecules protects us. Without this system, bacteria and viruses would quickly take hold of you."

"It's not that you can create super resistance." Titia van der Stelt, dietician

Titia Van der Stelt, dietitian and expert at nutrition platform I'm a Foodie: "It's not like you can create super resistance. It's about maintaining your resistance and not letting it deteriorate."

Wichers agrees that such a super resistance does not actually exist. "You cannot be susceptible for nothing. The immune system is varied, one is susceptible to this and the other to that. Even if you are strong in one area, it can go wrong in another area."

In the fall and winter we get less vitamin D through sunlight. (Photo: NU.nl/Marleen Fouchier)

What can you do for good resistance?

You can, however, do anything to help your immune system. "Make sure you have enough exercise and fitness. If you are fit, your resistance is also higher," says Van der Stelt. "Make sure you eat enough vitamins C and E with food. Eat 250 grams of vegetables per day and two pieces of fruit. For example, a kiwi, that is a real vitamin C bomb."

See also: Why we should eat more fiber - and that's how you do it

By eating different fibers, for example from whole grains and legumes, you feed the good intestinal bacteria. "These fibers contribute to a good immune system," says Van der Stelt.

You can also do something to prevent contamination of yourself and the people around you. "For example, it is better to sneeze in your elbow than in your hands, because you then have other things with your hands. In the toilet it is better to dry your hands should paper wipes than hold them under or in the hand blower. Hand blowers are a source of bacteria, research shows. "

If you do not fall within a high-risk group, it is not necessary to take extra vitamin or dietary supplements. In an earlier interview with NU.nl, Astrid Postma-Smeets, Nutrition Center expert, says that people who do, don't get sick less easily.