Sweetcorn

Maize (Zea mays) originated in Mexico, where it was domesticated from a wild grass called teosinte around 9,000 to 10,000 years ago. Over thousands of years, selective breeding transformed it from a small wild grass into one of the world’s most important crops, now grown across the globe.

Sweetcorn and maize – what’s the difference?

An ear of corn is made up of kernels arranged on a cob and wrapped in a husk. Sweetcorn refers to maize harvested while the kernels are still young, tender and sweet, so it is eaten as a vegetable. Maize, on the other hand, usually refers to crops grown to full maturity and harvested dry as a grain for flour, animal feed and other uses.

In the UK, sweetcorn is grown on a relatively small scale, while most maize is used for animal feed, especially as silage for dairy cattle. Some is also used for anaerobic digestion and energy generation.

Maize is a high-risk erosion crop as the plants leave soil exposed during much of the growing season and where maize replaces grassland, the risk of erosion is even higher, especially when planted on slopes. A large-scale shift towards a vegan diet could reduce demand for animal feed crops, free up land for other uses and make it easier to restore and protect forests and grassland.

What are the nutritional benefits?

Sweetcorn is often dismissed because it is naturally rich in starch, but it also provides valuable fibre, which helps slow digestion and supports a steadier rise in blood sugar after a meal. As part of an overall healthy diet, wholegrain corn foods can contribute to digestive health and may help lower the risk of chronic disease.

It is also a useful source of B vitamins, especially folate, and provides vitamin C, although levels can vary depending on freshness and processing. Tinned sweetcorn remains a practical option: it keeps its fibre but may be lower in vitamin C than fresh corn and is often available year-round at a lower cost.

Sweetcorn also contains carotenoids such as lutein and zeaxanthin, which are associated with eye health, along with smaller amounts of vitamin E, vitamin K, magnesium, potassium and protein.

Blue corn benefits

Corn is not only yellow – white, blue and purple varieties also exist. Darker varieties contain more pigments such as anthocyanins, which contribute to their colour and may increase their antioxidant content. Blue maize flour can be used to make tortillas, wraps and other dishes, with a slightly nutty flavour.

How to cook corn

Once sweetcorn is picked, its sugars begin to convert to starch, so it is best eaten soon after harvest. If you can, choose cobs with bright green husks and plump kernels, then refrigerate them until you are ready to cook. Sweetcorn can be steamed, boiled, baked or grilled and works well in salads, soups, salsas, fritters and barbecue dishes.

Maize flour can be used to make tortillas, polenta and other staple foods. Popcorn is made by heating dried kernels until the moisture inside expands and the kernels burst open.

A word of caution

Plain corn is generally gluten-free and suitable for people with coeliac disease, although a small number of studies suggest that some people may react to maize proteins called zeins. It may also trigger symptoms in some people with IBS, depending on individual tolerance.

For most people, though, sweetcorn is a versatile and nutritious addition to a healthy diet.