Consistency and variety - Nutrition for real immune support

We’re more inclined to huddle on the couch under a blanket than go for a walk. We get less sunshine on our skin and so our levels of protective Vitamin D drop. We swap out salads packed with raw vegetables and fruits for cooked comfort foods, reducing our intake of Vitamin C and other immune-supporting micro-nutrients. We close up the windows and doors to keep our indoor environments warmer, but this means we spend much more time in poorly ventilated spaces in closer contact with more germs.

In defence, we typically turn to the latest flu shot, as well as vitamin and mineral supplements in the hopes of giving our immune systems a protective ‘boost’. In actual fact, there is no way to ‘boost’ your immune system, but there are effective ways to support it through daily nutrition. As Registered Dietitian and spokesperson for ADSA (The Association for Dietetics in South Africa), Retha Harmse points out: “We must keep in mind that our immune system relies on consistent nourishment, not quick fixes. Multiple nutrients work together to keep immune defences strong, reduce inflammation, and help your body recover from illness. Therefore, if you want to reduce your risks of succumbing to winter colds and flu, it makes sense to double-down on your focus on daily nutrition as your first and most critical line of defence. My advice for optimal immune support in winter is to focus on variety – a colourful plate including plant and animal food sources, herbs, and spices supports immunity better than isolated nutrients or supplements.”

Mpho Tshukudu, another Registered Dietitian and ADSA spokesperson agrees: “A balanced diet made up of whole foods is more effective than supplements for supporting the immune system because of the concept known as the food matrix effect. Nutrients and compounds in foods don't act alone - they interact with each other and the structure of the food in intricate ways that influence how well our bodies can absorb and use them. Eating whole foods improves your digestion, nutritional absorption, and immunological response because you're consuming a complex variety of bioactive substances, fibre, proteins, fats, and phytonutrients rather than just individual vitamins and minerals. Taking separate nutritional supplements can't replicate these interactions.

“In colder months, when our bodies are under more stress and infection risk is higher, relying on supplements alone may miss out on the synergistic effects found in whole foods. An example of this is that Vitamin C in foods such as guavas and oranges is more effective for your immune system than the same amount in a supplement because of the surrounding matrix of fibre, phytonutrients and other nutrients that improve its absorption and usage.

The strength of your immune system is in your gut

This highlights why what you eat in winter matters - while our immune system is at work throughout our body, 70% of immune cells are in our gut. While you may need to use supplements to fill specific nutritional gaps due to illness, food allergies or digestive intolerances, it’s important to note that they cannot replicate the foundation of a consistent, nutrient-dense diet.

Synching with nature by eating seasonally is an important way of optimising immune support. In the winter months, the fresh produce provides so much of what we need to support and protect our bodies. For instance, there’s a natural abundance at this time of year of fruit and vegetables rich in Vitamins A and C.

Mpho explains that Vitamin A helps the body defend against viruses and bacteria. She says, “It occurs as beta-carotene in seasonal vegetables such as orange-fleshed sweet potatoes, pumpkins, butternut and dark leafy greens like morogo or spinach and kale. Winter is also the season for citrus fruits like naartjies, oranges, lemons, and grapefruits which, like guavas, are particularly rich in Vitamin C. This significant micro-nutrient supports the immune system in fighting off infections and reducing the severity of colds so that they do not develop into more serious respiratory illnesses.

What is important to remember is to eat a variety of fresh, uncooked and cooked vegetables and fruits, as both raw and cooked vegetables offer unique benefits.

Build base meals around seasonal produce by using winter staples like butternut, sweet potato, leeks, carrots, cabbage, and citrus. They're affordable, nutrient-rich, and naturally comforting. Roast them, blend into soups, or add them to stir-fries. Also, boost flavour and support immunity with warming spices and herbs. Garlic, turmeric, ginger, thyme, and cinnamon aren’t just flavourful - they help support immune function and reduce inflammation. Add garlic to stews and pasta sauces, turmeric to lentils and rice dishes, and ginger to curries, teas and stir-fries

Retha reminds us that gut health is a long game. Consistency and variety, not strict rules or quick interventions, lead to the best outcomes.

Retha’s top tips to support gut health in winter include:

• Increase fibre-rich foods – “Fibre is food for your gut bacteria. Include legumes such as lentils, chickpeas, and beans; whole grains such as oats and brown rice; fruits such as apples, pears, and bananas; and vegetables such as broccoli, carrots, and spinach.”

• Choose fermented foods regularly – “These contain probiotics which are beneficial bacteria. Add amasi, maas, live yoghurt, sauerkraut, kimchi, or kefir to your diet several times a week.”

• Rotate your plant foods – “Try to eat at least 30 different plant foods per week. This supports a greater diversity of the beneficial bacteria in your gut which is linked to better health.”

• Limit ultra-processed foods – “These often contain additives, refined sugar, and are low in fibre - all of which disrupt the gut barrier and feed inflammatory microbes.”

• Stay hydrated – “Water is essential for digestion, the gut lining, and microbiome balance. Aim for 6–8 glasses daily, or more in dry winter conditions.”

Managing children’s vulnerability to winter colds and flu through nutrition

It’s inevitable that children in preschool or primary school will get sick more often during winter. While this can be distressing for parents, we must bear in mind that exposure is part of how children’s immune systems mature. While diet can’t prevent all illness, it plays a protective role in reducing the severity of colds and flu and recovery time.

Parents should focus on sticking to routine, balanced meals and snacks by offering meals every 2 to 3 hours with a mix of protein such as boiled egg, cheese or yoghurt; healthy fats such as avocado or nut butters, and plenty of colourful fruits or vegetables. Add more nutrients into familiar meals by finely grating carrots into Bolognese sauce, blending baby marrow or mashed orange sweet potato into muffins, or stirring baby spinach into scrambled eggs. Add a fresh fruit or vegetable to each meal whenever possible.

Good hygiene becomes even more critical during the colder months. Keep the focus on regular handwashing - after the bathroom and outside play, before meals and after sneezing. Discourage the sharing of water bottles or utensils at school and make sure lunchboxes and water bottles are cleaned daily.

You might not be able to stave off every cold and flu bug during the upcoming winter months, but by keeping your focus on healthy eating choices for the whole family, you will support immune systems in fighting them off and recovering more quickly.

Retha Harmse’s Winter Veggie Mince for Kids

Makes: 4–6 servings
Prep time: 10 minutes
Cook time: 30 minutes

Ingredients:

• 1 tbsp olive oil
  
• 1 onion, finely chopped
  
• 2 cloves garlic, minced
  
• 1 grated carrot
  
• 1 grated baby marrow
  
• ½ cup finely chopped spinach (fresh or frozen)
  
• 500g lean beef or ostrich mince
  
• 1 tsp turmeric
  
• 1 tsp dried mixed herbs
  
• 1 tin chopped tomatoes
  
• 2 tbsp tomato paste
  
• ½ cup grated butternut (optional for added sweetness and fibre)
  
• ½ cup cooked lentils (or a tin, drained and rinsed)
  
• Salt and pepper to taste (go light on salt for younger children)

Optional add-ins:

• 1 tsp soy sauce (low sodium if needed)
  
• ½ tsp apple cider vinegar or lemon juice
  
• ½ tsp brown sugar or honey
  
• A pinch of ground ginger or mustard powder (optional for extra flavour)
  
• A handful of cooked brown mushrooms (slice and leave in the sun for at least 15 minutes for an extra Vitamin D boost)
  
• A dash of cinnamon for warmth and flavour

Instructions:

1. Heat the oil in a large pot over medium heat.
   
2. Sauté the onion and garlic for 3–4 minutes until soft.
   
3. Add the grated carrot, baby marrow, butternut, and spinach. Cook for another 5 minutes.
   
4. Stir in the mince, breaking it apart. Cook until browned.
   
5. Add turmeric, herbs, tomato paste, and chopped tomatoes. Simmer for 15–20 minutes, stirring occasionally.
   
6. Stir in the lentils and adjust seasoning. Simmer for another 5 minutes until everything is tender and well combined.
   

Serving ideas:

• Over brown rice or wholewheat pasta
  
• Stuffed into a wrap with grated cheese
  
• Inside a baked sweet potato
  
• Topped with mashed potato for a mini cottage pie

Parent tip: Let your child help with grating or stirring - kids are more likely to eat food they helped prepare.

Nutritional Information (per serve, serving approximately 250g)

Energy 1040 kJ | Protein 20.2 g | Carbohydrate 11.8 g | Of which total sugar 4.3 g | Total fat 16.8 g | Of which saturated fat 6.1 g | Dietary fibre 2.8 g | Total sodium 146.7 mg | GI (estimated) 40