5 foods and herbs to boost your immune system

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During the cooler months, strengthening the immune system becomes a focus for many people.

But our immune system does more than just help our body to ward off common colds and the flu – it also helps our body to react to foreign substances and forms part of our anti-cancer response.

The immune system function is also tied to energy. Whether this is your susceptibility to viruses or infections, glandular fever or simply hayfever, anything that triggers your immune system can be fatiguing. Getting to the heart of these reactions can replenish the energy that is currently being spent fighting these infections/reactions.

Really think about this next statement: what we eat becomes part of us. The protein foods you eat are broken down into amino acids, which go on to create all of the cells of your immune system, which helps to defend you from infection. Aside from supplying the building blocks for our immune cells, our food also provides the vitamins and minerals that our immune cells require to function properly. It really does matter what we eat. Your food becomes part of you.

Here are five foods and herbs that your immune system will love:


Lemons are a great source of vitamin C, an essential nutrient when it comes to an immune system that is firing on all cylinders. Vitamin C supports immune system function by promoting white blood cell proliferation and destroying histamine.

It's also present in the fluid lining in our lungs and mucous membranes, where the antioxidant activity helps prevent inflammation and damage by bacteria and viruses. Absorption of iron, a mineral that is critical for healthy immune system function, is enhanced in the presence of vitamin C, too.

Having some lemon juice in warm water before a meal can help to stimulate stomach acid production, which supports an optimal pH gradient in the digestive tract. This impacts how well we digest our food and enhances absorption of nutrients that are essential for the immune system, such as zinc.



Garlic is wonderful for boosting the immune system. To enhance the amount of allicin, the main bioactive compound in garlic, crush or chop the garlic and wait 10 minutes before cooking it. Garlic has anti-infective properties and is also a prebiotic, which means it contains fibres that nourish our gut bacteria. Around 70 per cent of the immune system is located in the gut, and the gut microbiome helps to modulate our immune responses.


Brazil nuts are the richest dietary source of selenium, an antioxidant that helps to regulate immune function and inflammation. Very few foods contain selenium as if a nutrient isn't in the soil, it can't be in our food. Just two to four brazil nuts per day is enough to meet your daily selenium requirement.


You might like to consider using Echinacea, as it has been used as an immune system supporting herb for centuries. It is best-used long term and helps to modulate the amount of white blood cells present, which are what fight infections in the body. For guidance with dosage and the use of Echinacea, please consult a medical herbalist.


Beef is one of the best dietary sources of iron and zinc, both of which are critical for immune system function and protecting against infection. It's also a source of high quality protein, which means it supplies amino acids that can go on to create our immune cells.

However, although good quality beef can be a highly nourishing food, it's not a case of "the more, the better" with beef or other red meats. The World Cancer Research Fund recommends consuming less than 500 grams of red meat per week to reduce the risk of colorectal cancer, so if beef nourishes you, go for quality over quantity – choose organic and grass-fed red meat.

Dr Libby is a nutritional biochemist, best-selling author and speaker. The advice contained in this column is not intended to be a substitute for direct, personalised advice from a health professional. Join Dr Libby for her upcoming 'What Am I Supposed To Eat?' New Zealand tour. For information and to buy tickets, visit drlibby.com

- Stuff