Immunity 101: What You Really Need This Cold Season

Note: the following is not professional medical advice. For personalised guidance on your immune health, talk to your GP.

As winter sets in and sniffles start to circulate, talk of “immunity boosters” becomes more common. Supermarket shelves fill with supplements and syrups claiming to shield us from every cough and sneeze, but how many of them really work?

The immune system is complex. It’s not something you can “boost” overnight with a single pill or potion. However, there are some well-supported ways to support immune health – especially important as we age, when our immune response naturally becomes less efficient.

So, let’s separate the fact from the folklore and take a closer look at what’s really worth your time (and money) this winter.

Backed by science: The big three

Vitamin C

Vitamin C has long been associated with immunity, and for good reason. It plays an important role in supporting various cellular functions of the immune system. While it won’t prevent you from catching a cold, studies have found regular supplementation may slightly reduce the duration and severity of symptoms – especially in people under physical stress or with low baseline levels.

You can get vitamin C through citrus fruits, berries, capsicum, broccoli, and tomatoes – or, if needed, through a supplement. But keep in mind: more isn’t always better. Your body excretes excess vitamin C, and very high doses can lead to stomach upset.

Vitamin D

This is a big one – especially in winter, when sunlight exposure (our main source of vitamin D) drops. Vitamin D helps modulate the immune response, and low levels have been associated with an increased risk of respiratory infections.

Older adults are more likely to be vitamin D deficient, particularly if they spend less time outdoors. In New Zealand, winter is a good time to talk to your doctor about whether you might benefit from a supplement. Some people may need a blood test to check their levels.

Zinc

Zinc is another essential mineral for immune function. It helps immune cells function properly and plays a role in inflammation regulation. Some evidence shows taking zinc at the first sign of cold symptoms may reduce the length of a cold – but only if taken within 24 hours of symptoms appearing, and at the right dose.

Too much zinc, however, can cause side effects and interfere with the absorption of other minerals like copper. As always, moderation is key. For short-term use, such as when you feel a cold coming on, slightly higher doses may be taken, but with care. 15–30 mg per day is commonly used in immune-boosting supplements.

Possibly helpful (but not proven): Traditional options

There’s a range of natural remedies people turn to for immune support, and while they don’t have the same scientific backing as vitamins C, D, or zinc, many have been used for generations. Just remember, these are not replacements for evidence-based prevention or treatment.

Elderberry

Elderberry has gained popularity for its supposed ability to reduce the severity and duration of colds and flu. Some small studies suggest it may have antiviral effects and help relieve symptoms, particularly when taken early. However, the evidence is not yet strong or consistent enough to call it a guaranteed immunity booster. Still, many people find it soothing and useful as part of a broader wellness approach.

Echinacea

A popular herb often used at the first sign of a cold. Some small studies suggest echinacea might slightly reduce cold symptoms or duration, but results are inconsistent. If you like using it and feel it helps, it’s probably not doing harm – but it’s not a guarantee either.

Garlic

Garlic has antibacterial and antiviral properties in the lab, and there’s some evidence that regular consumption may reduce the frequency of colds. However, the quality of research is low, and the effects – if any – are likely mild. That said, it’s a delicious, heart-healthy addition to your meals, and certainly won’t hurt.

Olive leaf extract

Often sold as a natural antiviral, olive leaf extract has shown some promise in lab studies, but again, human research is limited. While it’s unlikely to be a magic bullet, many people use it as part of a general wellness routine.

Honey

Raw honey—especially manuka honey—has long been used to soothe sore throats and calm coughs. It has natural antibacterial properties and can offer comfort during a cold. While it won’t prevent illness or “boost” immunity directly, it can be a helpful part of symptom relief. Just avoid giving it to children under one year old due to the risk of botulism.

The basics still matter most

Before you rush to stock up on supplements, remember your everyday habits play the biggest role in keeping your immune system ticking along nicely.

• Get enough sleep. Chronic sleep deprivation can suppress immune function. Aim for seven to nine hours a night.

• Eat a balanced diet. A variety of fruit, veg, whole grains, protein, and healthy fats provides the nutrients your body needs to defend itself.

• Stay active. Moderate exercise has been shown to support immune health. A brisk walk most days is a great start.

• Manage stress. Chronic stress can take a toll on the immune system. Simple practices like deep breathing, light stretching, gardening, or talking with a friend can all help.

• Keep up hygiene habits. Wash hands regularly and avoid touching your face – basic measures that remain incredibly effective.

• Talk to your doctor about vaccinations. Staying up to date with your flu and COVID-19 vaccinations helps protect not just you, but those around you.

A balanced approach

As winter wraps around us, it’s tempting to seek out a quick fix to avoid getting sick. But supporting your immune system is more about the long game – building healthy habits, getting enough of the nutrients your body needs, and listening to your body when it needs rest.

Supplements can be helpful in some situations, especially when dietary intake is lacking (this is one of our favourites). But they’re not a substitute for the basics, nor are all remedies created equal.

If in doubt, chat to your GP or pharmacist – especially before starting any new supplement, particularly if you’re already on medication or managing a health condition.

Because when it comes to winter wellness, a thoughtful, steady approach always beats a panic-buy at the pharmacy.