Nutritional boffins are singing the praises of a green veg that's packed with more vitamin C than your average orange, and Harvard hotshots are flagging up spinach as a top-notch immune system booster. Vitamin C, also dubbed ascorbic acid, is a bit of a wonder nutrient, famed for its cell-protecting prowess, skin and blood vessel maintenance, bone and cartilage support, and even its role in healing our scrapes and bruises.

The history books first mention spinach cropping up in 7th-century China, but it wasn't until the 11th century that this leafy green made its way to Spain, eventually spreading its roots across Europe and beyond. These days, more and more people are piling their plates high with spinach, clued-up on the need for a well-rounded, health-conscious diet.

Elisabeth Moore, a nutrition expert at the Beth Israel Deaconess Medical Centre, which rubs shoulders with Harvard, said: "Vegetables vary in terms of their content and nutrient density, flavour, and texture." In the grand lineup of veggies, spinach is said to take the crown for its nutritional value, according to the scientists at Harvard. It's not just about vitamin C – these leafy greens are also brimming with vitamins A, K, and folic acid, all essential players for an immune system that's firing on all cylinders.

Spinach packs a punch with antioxidants such as carotenoids and lutein, tackling oxidative stress and shielding cells from aging too soon. It's also brimming with fibre for smooth digestion and inflammation reduction.

Plus, it boasts vitamin A for white blood cell function – your body’s defenders – and vitamin K for sturdy bones and a healthy heart. The NHS advises: "Adults aged 19 to 64 need 40mg of vitamin C a day. You should be able to get all the vitamin C you need from your daily diet. Vitamin C cannot be stored in the body, so you need it in your diet every day."

Top nutrition expert Tim Spector champions adding this green superfood to your plate, suggesting that frozen veggies could trump fresh by preserving the all-important Vitamin C. Freezing spinach makes it simple to stir into meals over time without losing any goodness, he explains.

He recommends: "Like me, You probably always thought that fresh food is always the best option. Don't be a snob when it comes to frozen foods or canned foods that can often be lifesavers. An example is frozen spinach, and actually the freezing process and the way it's packed up means that those nutrients in spinach are perfectly preserved, so you don't lose anything from buying the fresh product."