Expert Karen Geary looks at how whole foods, spices and giving your gut what it loves can really boost your immune system this winter

The UK’s dietary supplements market continues to boom. Almost half of us take supplements – especially over the winter when we’re trying to fend off colds and flu.
But it is a highly unregulated industry and supplements can be wasteful or, worse, downright dangerous, depending upon your medical history and personal needs.
Supplements definitely have their place: but only when they are targeted, taken for a short period of time and only on recommendation from someone qualified.
While supplements are usually everyone’s go-to for a quick immune system boost, nature really does provide a pantry full of ingredients that can help keep your defences strong. Focusing on whole, nutrient-dense foods can give your immune system the jetpack it needs during winter. Here’s how to make your plate a powerhouse of immunity:

Vitamin C
Everyone knows it’s in oranges (and all citrus fruit), but it’s also found in bell peppers, tomatoes, Brussels sprouts and kiwi. It’s an antioxidant which supports the production of white blood cells. Vitamin C also increases the absorption of non-heme iron (plant-based iron). Pairing iron-rich plant foods like spinach with vitamin C-rich foods like bell peppers can improve your iron uptake.
Tip: Oranges are in abundance this time of year in supermarkets and are great value. Slice one into a winter salad.

• Did you know? One little-known vitamin C powerhouse is nettle tea, which is also a good source of calcium and iron. Two cups of nettle a day is great for building a consistent dose.

Zinc
Zinc is a cornerstone mineral for immune function. The richest food sources of zinc include meat, fish and seafood. While oysters are famous for their zinc content, more accessible sources include meat, shellfish, nuts and seeds, dairy, chickpeas and lentils. Bring on the hummus and sprinkle pumpkin seeds on top!
Tip: Liver has a high zinc content and is great value for money. If it’s not your favourite to eat, make your own chicken liver pate!

• Did you know? All nutrients compete with one another, but some have mutual benefits (bioavailability). One mutually-beneficial nutrient with zinc is magnesium. Dark chocolate contains both! Just make it more than 85% cacao.

Vitamin D
Vitamin D is technically a hormone and is my one exception: supplementation may be essential. Vitamin D deficiency is notably prevalent in the UK, especially during the winter months as it is very difficult to get sufficient sources from food.
The NHS recommends that all adults take a vitamin D supplement over the winter. It works best if you can dose accordingly to your current levels, but testing and dose recommendations are best done by a qualified professional. The majority of my clients are vitamin D deficient when tested.
Known as the “sunshine vitamin” (we absorb it through the skin via sunlight), it’s also present in fatty fish like salmon, egg yolks and fortified foods.
Tip: Include plenty of mushrooms in your meals: they’re a rare plant-based source of vitamin D. Vitamin D is fat-soluble, so garlic mushrooms gently cooked in olive oil are a winner.

• Did you know? Vitamin D enhances calcium absorption, benefiting bone health. Consuming vitamin D-rich foods like oily fish alongside calcium-rich foods such as dairy products can be advantageous. So eat the bones from that tin of sardines for maximum benefit!

Spice up your life
Herbs and spices don’t just flavour your meals: they’re nature’s pharmacy for immune support. Garlic is rich in allicin, a compound known to enhance the body’s ability to combat colds.
Ginger, with its anti-inflammatory properties, can ease congestion and throat discomfort.
Turmeric, loaded with curcumin, helps combat inflammation. If you like curries and stir-fries, this is for you.
Tip: Create a warm, immune-boosting tea by steeping ginger slices, turmeric and a touch of honey in hot water. Alternatively, turmeric chai latte is also delicious. You can take your pick from the countless recipes online.

• Did you know? Pairing turmeric with black pepper can enhance curcumin absorption (bioavailability). Add a pinch to your turmeric dishes.

Fibre and the microbiome connection
Your gut microbiome plays a significant role in immune health and fibre is its favourite food! Prebiotic-rich options like oats, bananas, artichokes and onions feed the good bacteria, fostering a thriving gut environment. Pair fibre-rich meals with fermented foods like yoghurt or kimchi to supercharge your microbiome.

• Did you know? About 70 per cent of your immune system lives in your gut. Supporting it is like fortifying your body’s headquarters.
  Your immune system thrives when it is nourished by whole, nutrient-dense foods. Pairing complementary nutrients and embracing seasonal, gut-friendly choices can keep you resilient during winter. Oh, and have another glass of water –
  hydration is essential too!
  With nature’s pharmacy at your fingertips, staying well has never been more delicious.

Comfort in a bowl: fighting colds with French Onion Soup

When you’re battling a streaming cold, it’s all about finding comfort while giving your body what it needs to heal. Enter French onion soup, the ultimate kitchen remedy that’s as therapeutic as it is delicious.
Onions are rich in quercetin, a natural compound known for anti-inflammatory and antihistamine properties – perfect for soothing that relentless runny nose. They also contain sulphur compounds, which help support immune function and clear mucus. Pair that with warming bone broth and garlic, and you’ve got a recipe designed to work as hard as you do at feeling better.
This soup is more than just a meal—it’s a hug in a bowl, giving you warmth and nourishment when you need it most:

Serves 4 (or 2 hungry people)

• 500g onions sliced
• 3 tbsp of olive oil
• 3 sprigs of thyme (or 1 tbsp dried)
• salt
• pepper
• 1/2 tsp soft brown sugar
• 1 garlic clove, large, peeled and crushed
• 125ml of dry white wine
• 1l bone broth

1. Preheat the oven to 200°C.
2. Add the sliced onions, olive oil and thyme sprigs to a large heavy-duty pan or roasting tray, season with salt and pepper and hand mix to combine.
3. Cover and place in the oven for 45 minutes, giving the onions a stir halfway through.
4. After 45 minutes, remove the foil and the thyme sprigs.
5. Stir, sprinkle over the sugar then roast uncovered for 15 minutes
6. Add the crushed garlic, stir well again and roast uncovered for a further 15 minutes
7. Remove the tray from the oven and transfer the onion mix to a pan over a medium heat on the hob. Add the wine, stir well and allow to bubble for 3 to 4 minutes.
8. Add the broth and simmer for 10 minutes.
9. Adjust seasoning and serve.
10. Serving with melted cheese on toast on top – entirely optional, but highly recommended!

Follow Karen on @amplifynutrionaltherapy for more recipes and advice