There is something about September that feels like a reset.
Children go back to school, work routines return after the summer holidays, the mornings become cooler and we gradually begin spending more time indoors.
And then come the coughs, colds and seasonal bugs.
At this time of year, we’re surrounded by advice about how to “boost” the immune system. But as I’ve explored in recent articles, immune health isn’t really about making our immune response stronger.
A healthy immune system needs to be balanced and well regulated.
It needs to recognise potential threats, respond appropriately, control inflammation, protect our own tissues and then know when to stand down again.
So rather than looking for a single food, supplement or remedy to keep every autumn bug at bay, this is a good time to look at the foundations that help support normal immune function — for adults and children alike.
Back to School Means Back to Bugs
For children, September can mean suddenly moving from the relative freedom of the summer holidays into classrooms, playgrounds, clubs and other busy environments.
They’re sharing tables, toys, sports equipment and indoor spaces with dozens of other children again.
Exposure to viruses and other microorganisms is an ordinary part of life, and we can’t — and shouldn’t try to — create a completely germ-free environment for children.
What we can do is make sure growing bodies have the nutritional and lifestyle foundations they need to support normal immune function.
That starts with some very ordinary things.
Food: Variety Really Does Matter
The immune system is enormously complex and requires many different nutrients to function normally.
Rather than concentrating on one supposedly “immune-boosting” food, aim for variety.
Different-coloured fruit and vegetables provide different vitamins, minerals and plant compounds. Protein supplies amino acids needed throughout the body, while healthy fats, whole grains, pulses, nuts and seeds all contribute to a nutrient-rich diet.
For children, this doesn’t have to mean creating a perfect plate at every meal.
Looking at what they eat across a day — or even a week — can often be much more realistic.
And if you have a selective eater, introducing variety gradually and without turning every mealtime into a battle can be far more helpful than aiming for dietary perfection.
Don’t Forget the Gut
Our digestive system and immune system are intimately connected.
The gut is home to a vast community of microorganisms collectively known as the gut microbiome, and communication between these microbes, the intestinal barrier and immune cells plays an important role in immune regulation.
Dietary variety is important here too.
Plant foods provide different types of fibre and compounds that our gut microbes can use, while fermented foods can be another useful addition for people who tolerate them.
Again, there isn’t one magical “gut health” food.
Diversity matters.
Sleep Is Part of Immune Health Too
Nutrition gets much of the attention, but our immune system doesn’t operate separately from the rest of us.
Sleep, physical activity and stress all influence our overall health.
September can be particularly disruptive for families. Children may suddenly need to get up much earlier for school, while after-school activities, homework and changing routines can make evenings busy.
Adults aren’t immune to the September reset either.
Creating a reasonably consistent sleep routine, allowing children downtime after school, spending time outdoors and building movement into family life can all form part of supporting health through the changing season.
It doesn’t need to be complicated.
Sometimes the foundations really are the most important things.
Autumn Is Your Reminder to Think About Vitamin D
There is one nutrient that deserves particular attention at this time of year: vitamin D.
Our bodies can make vitamin D when sunlight reaches our skin. However, in the UK, between October and early March, sunlight does not contain enough UVB for us to make sufficient vitamin D this way.
Vitamin D is important for maintaining healthy bones, teeth and muscles and also contributes to the normal functioning of the immune system.
There are some dietary sources, including oily fish such as salmon, sardines and mackerel, egg yolks and certain fortified foods.
However, it’s difficult to obtain enough from food alone.
Current UK guidance recommends that adults and children over four should consider a daily supplement containing 10 micrograms of vitamin D during autumn and winter. Children aged one to four should receive 10 micrograms daily throughout the year, while recommendations for babies vary depending on age and whether they are breast- or formula-fed.
Some people are also advised to consider vitamin D supplementation throughout the year because they may not produce enough from sunlight.
What About Supplements?
Supplements can have a place, but the word itself is important.
They supplement the foundations of a healthy diet and lifestyle rather than replacing them.
Individual requirements can also be very different.
Age, diet, health conditions, medications and nutritional status can all affect what is appropriate, which is why more isn’t necessarily better.
This is particularly important with children. If you’re already giving your child a vitamin or mineral supplement, check the ingredients before adding another product so you don’t inadvertently double up on particular nutrients. The NHS specifically advises parents to be careful about giving two supplements containing the same vitamins.
From “Immune Boosting” to Immune Support
Perhaps this is the biggest shift I’d encourage families to make this autumn.
Instead of asking:
“How can I boost my family’s immune systems?”
try asking:
“What does our immune system need in order to function well?”
That changes the conversation.
It takes us away from miracle ingredients and quick fixes and brings us back to the interconnected foundations of health:
Good nutrition. A healthy gut. Adequate sleep. Movement. Time outdoors. Stress management. Appropriate nutrients, including vitamin D.
None of these can guarantee that your family won’t catch a cold when the latest bug works its way around the classroom or office.
But health isn’t about creating an impenetrable shield.
It’s about supporting the body’s ability to respond, regulate and recover.
And the change of season is a very good time to check that those foundations are in place.
Further reading
For current UK vitamin D recommendations, see the NHS guidance on vitamin D.
For advice specifically covering babies and younger children, see the NHS guidance on vitamins for children
