The festive season can be a time when winter illnesses are rife as people meet up to enjoy the festivities. 

Strep A has been a concern for parents in the lead-up to Christmas but it can also be a time when people fall ill with the common cold or even the flu amid the colder weather. 

While eating certain foods won't prevent you from getting ill, it may help to boost your immune system, thus making it easier to fight off a number of virus'.

So, as you head to the supermarket for your next shop, it might be worth picking up a few of these immune system boosters.

A word of warning, however - if you fall into the high-risk category, have an underlying illness or are concerned about your health - always speak to a medical professional before dramatically changing your diet.

  • Citrus fruits

According to the health guidance website, Healthline, most people turn to vitamin C after they've caught a cold. That’s because it helps build up your immune system. Vitamin C is thought to increase the production of white blood cells. These are key to fighting infections.

Popular citrus fruits include grapefruit, oranges, tangerines, lemons, limes and clementines.

  • Zinc

“Zinc is necessary for a healthy immune system," according to Melissa Snover, founder and CEO of Nourished.

"A lack of zinc can make a person more susceptible to disease and illness.

"This essential nutrient helps maintain the body’s ability to make new cells and enzymes, process carbohydrate, fat and protein in food and also increases the speed of healing muscles and wounds."

Foods high in zinc include red meat, shellfish, eggs, nuts, wholegrains and legumes, such as chickpeas, lentils and beans.

  • Broccoli

Broccoli is supercharged with vitamins and minerals. Packed with vitamins A, C, and E, as well as many other antioxidants and fibre, broccoli is one of the healthiest vegetables you can put on your table. The key to keeping its power intact is to cook it as little as possible - or better yet, not at all.

  • Ginger

Ginger is another ingredient many turn to when they are feeling under the weather. The antioxidant is believed to fight off cold and flu symptoms, combat nausea, and is full of iron, zinc, calcium and magnesium.

However, it’s worth noting that a study from 2013 showed fresh ginger may help boost the body’s respiratory system, but dry ginger did not show the same results.

  • Garlic

Before it became a staple in cooking, garlic was actually used for medicinal purposes. From manganese to vitamin B6 and C, as well as selenium and fibre, it is high in immune-boosting compounds.

"Garlic is a potent anti-viral, anti-fungal agent, and eating it raw, or as an uncooked puree alongside your normal food (add it to salad dressings) will wipe-out most miscreants," Sara Davenport, health expert and author of Reboot Your Health told the Metro.

  • Yogurt

Look for yogurts that have 'live and active cultures' printed on the label, like Greek yogurt. These cultures may stimulate your immune system to help fight diseases.

According to Healthline, yogurt can also be a great source of vitamin D, so try to select brands fortified with vitamin D. Vitamin D helps regulate the immune system and is thought to boost our body’s natural defences against diseases.

  • Sunflower seeds

Sunflower seeds are full of nutrients, including phosphorus, magnesium, and vitamin B6. They’re also incredibly high in vitamin E, a powerful antioxidant.

Vitamin E is important in regulating and maintaining immune system function. Other foods with high amounts of vitamin E include avocados and dark leafy greens.

  • Mushrooms

"There are approximately 400 species of fungi that have been identified with medicinal properties, and many have antiviral, antimicrobial or anti-inflammatory qualities," says Euan MacLennan, herbal director at Pukka Herbs and medical herbalist at an NHS practice in London.

"Mushrooms are high in beta glucans – natural substances found to help 'prime' our immune system, making sure it’s ready for action to fight off infection."

  • Red peppers

According to Healthline, red peppers contain twice as much vitamin C as citrus. They’re also a rich source of beta carotene. Besides boosting your immune system, vitamin C may help maintain healthy skin. Beta carotene helps keep your eyes and skin healthy.

  • Fermented foods

“If you like saurkraut, miso, kefir and their immune-boosting relatives, add just a spoonful or two each day to your diet,” says Sara Davenport.

“Fermented foods encourage the growth of good bacteria in your gut and when their levels are high, so are your immune levels, defending you from viral infections.”