Eight fruit and vegetables that deliver a nutritional hit

Sweet potato can be used in soups, made into chips or pasta and roasted for a vitamin C hit.
Sweet potato can be used in soups, made into chips or pasta and roasted for a vitamin C hit.  Photo: Edwina Pickles

Can you optimise your immune system - and how? It's a question many are asking in the current COVID-19 crisis, and specific recommendations on the exact foods we should be focusing our dietary intake around can help us guide our cooking and shopping.

While there is no single food that will boost immunity, ensuring the body has access to the key nutrients it needs to help fight infection is important, especially when very few of us consume the recommended number of serves of fresh fruits and vegetables we need every day. 

Health hit: Capsicums offer between 140-190mg of vitamin C per cup.
Health hit: Capsicums offer between 140-190mg of vitamin C per cup. Photo: Williams Meppem

So before you start popping extra vitamin C tablets to ward off viruses, here are some natural superfoods to pack your diet full of over the next few weeks and months.

Capsicum

When we think of vitamin C we tend to think of citrus fruits - and while oranges and lemons are rich sources of vitamin C, they do not contain anywhere near as much as yellow and red capsicums do. Although capsicums can be expensive, they do pack a particularly strong nutritional punch, offering between 140-190mg of vitamin C per cup. This translates to four to five times the minimum amount of vitamin C we should be consuming daily in a single serve.

Bleached Japanese mustard spinach dressed in a savory noodle soup base sauce (Komatsuna Mentsuyuae) is a veggie side dish commonly served in Japan. Mustard spinach, komatsuna or Japanese mustard spinach
iStock

Mustard spinach is commonly served in Japan as a side dish. Photo: iStock

Mustard spinach

Also known as "komatsuna" or Japanese mustard spinach, this leafy green may not be your traditional go-to green veg but from a nutritional perspective it is worth considering. Mustard spinach contains a massive 200mg of vitamin C in a single cup and can be enjoyed raw or cooked - but keep in mind that heating vitamin C can destroy the vitamin so only cook it lightly for a brief period of time. Serving leafy greens with extra virgin olive oil will maximise nutrient absorption.

Green chilli and ginger grilled salmon skewers.

Grilled salmon skewers with green chilli and ginger. Photo: Con Poulos

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Green chilli

With a single green chilli offering more than 100mg of vitamin C, it's a smart idea to turn up the heat of your favourite soups, stir fries and meat dishes. Chilli is also a natural source of capsaicin, a molecule known to help reduce inflammation in the body.

Kale chips.

A single cup of kale offers 80mg of vitamin C. Photo: Edwina Pickles

Kale

Kale is frequently touted in health circles and there's a reason why - its high antioxidant content, anti-cancer properties and exceptionally high beta carotene (the precursor to vitamin A) and vitamin C content. A single cup of kale offers 80mg of vitamin C, or twice the recommended daily intake. To retain as much nutrition in kale as possible, enjoy raw or lightly cooked at low temperatures with extra virgin olive oil and squeeze of lemon to help neutralise the slight bitterness.

Bok choy with garlic sauce.

Bok choy with garlic sauce. Photo: William Meppem

Garlic

Garlic has been used to treat bacteria, high blood pressure and infection for thousands of years and it is believed that the organosulfides (naturally occurring chemicals found in garlic and onions), along with vitamin D, help to stimulate the production of a type of immune cell called macrophages.Garlic has also been shown to help support the growth of good gut bacteria, which play a crucial role in immune function. Garlic can be used in cooking in an endless range of meals and cuisines, as well as eaten raw or in supplementary capsule form. Remember to get some sunlight to enhance its potential benefits.

Salt and pepper brussels sprouts.

Salt and pepper brussels sprouts. Photo: William Meppem

Brussel sprouts

Love them or hate them, we cannot deny that brussel sprouts are an exceptionally nutrient-rich vegetable with lots to offer the immune system. A member of the nutrient-rich cruciferous family, brussel sprouts offer 100mg of vitamin C per cup, along with powerful prebiotic fibres that have been shown to play a key role in keeping our gut healthy. As a number of their key nutrients are heat sensitive, be sure not to overcook them. They can be enjoyed raw, and taste great shaved with extra virgin olive oil and a little honey and fresh walnuts.

Fresh ginger.

Ginger has a range of bioactive compounds. Photo: iStock

Ginger

One of the few foods to have some evidence to support its use in treating and managing viruses, ginger has been shown to help reduce the inflammatory response to colds and flu thanks to its range of bioactive compounds. It's best consumed raw rather than in a powdered or supplementary form to help retain as many of these active components as possible. Load up on ginger in your cooking, or make your own fresh ginger tea with honey and lemon to help soothe sore throats and improve recovery time if you have been struck down with a bug.

One-tray wonder: Baked sweet potato and sausages.

One-tray wonder: Baked sweet potato and sausages. Photo: William Meppem

Sweet potato

A hearty vegetable that can keep for relatively long periods of time, sweet potato is not only a source of vitamin C but an exceptionally rich source of beta carotene, the nutrient involved in the production of vitamin A in the body and a nutrient associated with mediating immune responses in the body. Sweet potato is extremely versatile and can be used in soups, made into chips or pasta and roasted for another daily serve of vitamin C and beta carotene.