It’s November, the school bugs have arrived, and it feels like your child has had a runny nose since September. One cold clears up, the next one starts. If you feel like your child is always sick, you’re far from alone, and in most cases it’s not a sign that something is wrong.
In this guide I’ll explain what’s actually normal, which nutrients have real evidence behind them, where supplements fit (and where they don’t), and when it’s time to see your GP or paediatrician.
Why Is My Child Always Sick? What’s Normal
Children’s immune systems are still learning. Every cold is a new virus they haven’t met before, and nursery and school are perfect places for viruses to spread: lots of children, close contact, shared toys and hands that go straight into mouths.
As a rough guide:
Babies, toddlers and preschoolers commonly have 6 to 8 colds a year, and children in nursery can have 10 to 12.
School-age children typically have around 5 to 6 a year.
Each cold can last 7 to 10 days, and a cough can hang around for 2 to 3 weeks.
Put those numbers together and a perfectly healthy child can seem unwell for much of the winter. The good news is that this usually settles as they get older and build up immunity.
What matters more than the number of colds is how your child is between them. If they bounce back, have good energy, eat reasonably well and are growing normally, that’s reassuring.
When to See Your GP or Paediatrician
Please get medical advice if your child:
Has a fever in a baby under 3 months, or a fever lasting more than 3 days at any age
Is struggling to breathe, breathing fast, or you can see the skin pulling in between the ribs
Is unusually drowsy, floppy or hard to wake
Is not drinking, or has far fewer wet nappies than usual
Has frequent ear infections, chest infections or pneumonia, or keeps needing antibiotics
Isn’t growing or gaining weight as expected, or has infections that never fully clear
Trust your instincts. You know your child best.
How Nutrition Supports Your Child’s Immune System
You can’t (and shouldn’t want to) “boost” the immune system like turning up a dial. What you can do is make sure it has everything it needs to do its job well. Here’s where the evidence is strongest.
Protein: The Building Blocks of Immunity
Antibodies and immune cells are made from protein. Most children in Spain and the UK get enough, but picky eaters who live on toast, pasta and crackers can fall short. Aim for a protein source at each meal: eggs, yoghurt, fish, chicken, beans, lentils, tofu or nut butters.
Vitamin D: Important, but Not a Magic Shield
Vitamin D supports immune function, and low levels are common in winter, even in sunny Barcelona, because children spend more time indoors and the sun is weaker.
The research is more nuanced than social media suggests. An earlier large meta-analysis found a small protective effect of vitamin D against respiratory infections. However, the most recent update from 2025, which pooled data from over 61,000 participants, found the effect was no longer statistically significant overall, and the benefit did not clearly differ by age.
My honest take: vitamin D is about correcting low levels, not preventing every cold. Babies and young children often have specific vitamin D recommendations, so follow your paediatrician’s guidance, and if your child rarely gets outside or has darker skin, ask whether a test or supplement makes sense.
Food sources include oily fish (salmon, sardines, mackerel), eggs and fortified foods, although food alone rarely provides enough in winter.
Zinc: Get It From Food First
Zinc is essential for immune cells to develop and work properly. A 2024 Cochrane review found that zinc supplements may have little or no effect on preventing colds in healthy people, although they might shorten colds that have already started, with more side effects such as nausea and an unpleasant taste.
So for most children, the focus should be food: meat, fish, eggs, dairy, lentils, chickpeas, pumpkin seeds, oats and wholegrains.
Vitamin C and Colourful Fruit and Veg
Vitamin C, vitamin A (from orange and dark green veg) and plant compounds called polyphenols all play a role in immune defence. You don’t need fancy products. Citrus, peppers, broccoli, berries and kiwis are brilliant. In fact, kiwi fruit is one of the richest everyday sources of vitamin C, and kids tend to love scooping one out with a spoon.
If vegetables are a daily battle in your house, have a look at my guide on how to get kids eating more fruit and vegetables without hiding them.
Fibre and the Gut: Where Much of the Immune System Lives
A large part of the immune system sits in and around the gut, and the gut bacteria help train it. Fibre from vegetables, fruit, oats, beans and wholegrains feeds these beneficial bacteria. Much of this evidence comes from mechanistic and observational studies, so we can’t say a high-fibre diet prevents colds, but it is a sensible foundation for overall health.
Fermented foods such as natural yoghurt and kefir are an easy addition for many children.
Mario's tip
Don't try to fix everything at once. Pick one "immune upgrade" per week: a kiwi at breakfast, a handful of lentils in the pasta sauce, a yoghurt after school. Small, repeated wins work far better than a perfect plan that lasts three days.
Sleep: The Underrated Immune Support
Sleep is when the body does much of its repair and immune work. A systematic review found that shorter sleep was linked to around 30% higher odds of upper respiratory infections. That review was in adults, so we should be careful applying it directly to children, but the principle makes sense, and children need far more sleep than adults:
3 to 5 years: 10 to 13 hours (including naps)
6 to 12 years: 9 to 12 hours
Teenagers: 8 to 10 hours
Late Spanish dinners and screens before bed can easily eat into this. A consistent bedtime, a calm wind-down routine and screens off an hour before sleep make a real difference.
Handwashing: Simple but Helpful
A systematic review of studies in schools and nurseries found that hand hygiene programmes may reduce respiratory infections and sick days, although the quality of the studies was mixed. Teaching children to wash hands before eating and after coming home is still one of the easiest wins you have.
What About Supplements for Kids’ Immunity?
This is the question I get asked most by parents. My approach is always food first, then supplements.
Here’s an honest summary of the evidence:
Vitamin D: useful to correct low levels and often recommended for young children, but not a guaranteed shield against colds.
Probiotics: a 2022 Cochrane review found that people taking probiotics were probably less likely to have repeated upper respiratory infections and less likely to need antibiotics. The evidence is low to moderate certainty, and the benefit depends on the specific strain, so not every product will help.
Zinc: little evidence for preventing colds in well-nourished children. Avoid giving zinc long term without guidance, as too much can interfere with copper absorption.
Multivitamins: can act as a safety net for very picky eaters, but they don’t replace a varied diet.
Always choose products designed for children, check the dose for their age, and speak to your paediatrician or a qualified practitioner first, especially if your child has a health condition or takes any medication.
Recipe idea: Golden Lentil & Veg Soup (serves 4)
A cosy, budget-friendly soup packed with protein, zinc, fibre and beta-carotene. Blend it smooth for fussy eaters.
- 1 tbsp olive oil
- 1 onion, chopped
- 2 carrots, chopped
- 1 small sweet potato, peeled and cubed
- 1 garlic clove, crushed
- 150 g red lentils, rinsed
- 1 litre low-salt vegetable stock
- ½ tsp ground cumin or turmeric (optional)
- Squeeze of lemon, natural yoghurt to serve
Method: Soften the onion and carrot in the olive oil for 5 minutes. Add the garlic and spice for 1 minute, then the sweet potato, lentils and stock. Simmer for 20 minutes until soft. Blend, add a squeeze of lemon and serve with a spoonful of yoghurt.
The Whole Family Matters Too
Children don’t eat in a vacuum. When parents are run down, stressed and sleeping badly, family meals and routines are the first things to slip. Many of the same habits that support your child also support you, and my article on boosting your immunity with nutrition and lifestyle tips is a good starting point for the grown-ups.
How I Can Help
If your child seems to catch everything, is a very selective eater, or you’re simply unsure which supplements are worth it, I can help you build a realistic plan for your family. In a consultation, we can:
Look at what your child is actually eating and spot any gaps (protein, iron, zinc, vitamin D, fibre)
Create simple, child-friendly meal and snack ideas that fit your routine
Discuss whether it’s worth asking your paediatrician about tests such as vitamin D or iron levels
Give honest, age-appropriate guidance on supplements, so you don’t waste money on the wrong ones
For parents who want support for themselves too, my 3-Month Health Optimisation Programme covers nutrition, sleep, stress and energy for the whole household. I work in English and German, in person in Barcelona and online.
Ready for a calmer winter? Book a consultation and let’s make a plan that works for your family.
FAQ
How many colds a year is normal for a child?
Young children commonly have 6 to 8 colds a year, and those in nursery can have 10 to 12. School-age children usually have around 5 to 6. As long as your child recovers well between illnesses and is growing normally, this is generally part of a healthy, developing immune system.
What foods help my child's immune system?
Focus on a varied diet with protein at each meal (eggs, yoghurt, fish, beans, lentils), colourful fruit and vegetables for vitamin C and vitamin A, zinc-rich foods such as meat, lentils and pumpkin seeds, and plenty of fibre from oats, beans and wholegrains to support the gut.
Should I give my child vitamin D in winter?
Many children have lower vitamin D levels in winter, and young children often have specific recommendations. Recent research suggests vitamin D is more about correcting low levels than preventing every cold. Ask your paediatrician what is right for your child's age and circumstances.
Do probiotics help children get fewer colds?
A Cochrane review found that probiotics may reduce repeated respiratory infections and the need for antibiotics, but the evidence is low to moderate certainty and depends on the specific strain. Fermented foods like yoghurt and kefir are an easy place to start.
When should I worry that my child is always sick?
See your GP or paediatrician if your child has frequent ear or chest infections, keeps needing antibiotics, is not growing or gaining weight as expected, has infections that never fully clear, or shows signs such as breathing difficulties, a long-lasting fever or unusual drowsiness.
View scientific references
Jolliffe DA, Camargo CA Jr, Sluyter JD, Aglipay M, Aloia JF, Bergman P, et al. Vitamin D supplementation to prevent acute respiratory infections: systematic review and meta-analysis of stratified aggregate data . The Lancet Diabetes & Endocrinology. 2025;13(4):307-320.
Nault D, Machingo TA, Shipper AG, Antiporta DA, Hamel C, Nourouzpour S, et al. Zinc for prevention and treatment of the common cold . Cochrane Database of Systematic Reviews. 2024;5(5):CD014914.
Robinson CH, Albury C, McCartney D, Fletcher B, Roberts N, Jury I, et al. The relationship between duration and quality of sleep and upper respiratory tract infections: a systematic review . Family Practice. 2021;38(6):802-810.
Willmott M, Nicholson A, Busse H, MacArthur GJ, Brookes S, Campbell R. Effectiveness of hand hygiene interventions in reducing illness absence among children in educational settings: a systematic review and meta-analysis . Archives of Disease in Childhood. 2016;101(1):42-50.
Zhao Y, Dong BR, Hao Q. Probiotics for preventing acute upper respiratory tract infections . Cochrane Database of Systematic Reviews. 2022;8(8):CD006895.
