Eating seasonal vegetables in winter brings surprising health benefits

December 2020 Healthy Living Willem van Altena

Eating vegetables is truly a year-round thing, even though many people mostly associate it with spring and summer. Okay, so a fresh green salad may not be seasonal in december, but that doesn’t mean that there aren’t plenty of other green options. And many of these are grown locally and do not involve flights from across the globe, or greenhouses. Some vegetables actually thrive in our cold climate and can even survive a blanket of snow. Where lettuce may turn to a squishy mush as soon as the frost sets in, typical winter vegetables remain crispy and nutritious. But eating cabbages and root vegetables isn’t just delicious: it is also very healthy. We have listed ten winter vegetables for you along with the health benefits they bring. And for each of these vegetables we include links to scientific research that investigates these health claims.

Why do some vegetables thrive in ice-cold conditions? Sugar is key to their survival strategy. When cold weather sets in, some plants are able to defend themselves by changing their starch content into sugar. By adding sugar to the water in their roots and leaves, plants can lower their freezing point, and this keeps them alive in sub-zero temperatures. Additionally, this process results in cold-hardy vegetables tasting sweeter in the cooler months, making winter the optimal time for harvest.

Kale

This leafy green is not only one of the healthiest vegetables, but it also happens to thrive in cooler weather. Kale –known in Dutch as ‘boerenkool’ of farmers’ cabbage, ‘chou frise’ (curly cabbage) in French- is a member of the cruciferous vegetable family, which includes many cold-tolerant plants like Brussels sprouts, cabbage and turnips. Cruciferous vegetables contain nutrients called flavonoids, and these have many proven health benefits.

Kale can be harvested year-round, but is at its best after it has been exposed to frost. Traditionally used in hearty dishes with mashed potatoes, bacon and sausages (‘stoemp’ in Flemish), kale has become something of a health food staple in the last decade, suddenly appearing in salads, stir-frys and even smoothies. No wonder, because kale is packed with vitamins, minerals, fiber, antioxidants and powerful plant compounds. One serving of kale contains all the vitamin A, C and K you need for the day. And it is also rich in B vitamins, calcium, copper, manganese, potassium and magnesium.

But it’s the flavonoid antioxidants like quercetin and kaempferol that really pack the biggest punch. Some studies suggest that a diet high in flavonoids may help reduce the risk of certain cancers like lung and esophageal cancer.

Further reading

–              Possible effects of kaempferol on certain types of cancer.
–              Flavonoids and their health benefits.

Brussels Sprouts

Ah yes, who can forget the pride of Belgium when it comes to vegetables, even though you’ll be hard-pressed to find extensive fields of these iconic mini-cabbages in the capital. Brussels sprouts are a member of the nutrient-rich cruciferous vegetable family. Because of their tightly packed leaves, Brussels sprouts are very hardy during cold weather, and it is for this reason that they frequently turn up at Christmas dinners worldwide. And for their size, Brussels sprouts contain an impressive amount of nutrients.

Brussels sprouts are an excellent source of vitamin K. Just 150 grams of cooked Brussels sprouts contains 137% of your daily recommended intake. Vitamin K is critical for bone and heart health and is important for brain function. Vitamin A, B and C are also found in Brussels sprouts in abundance, as well as manganese and potassium, and soluble fiber, which plays an essential part in the digestive process and can be very beneficial for diabetics. Another compound in Brussels sprouts is alpha-lipoic acid, an antioxidant that may reduce high blood sugar levels and increase the body’s sensitivity to insulin. It has also been shown to reduce the symptoms of diabetic neuropathy.

Further reading

Carrots

This popular root vegetable can be harvested in the summer months but reaches peak sweetness in fall and winter. Chilly conditions cause carrots to convert stored starches into sugars to keep the water in their cells from freezing. This makes carrots taste extra sweet in cooler weather. Carrots contain lots of beta-carotene, which is converted to vitamin A in the body. One large carrot contains more than twice the daily recommended intake of vitamin A. Vitamine A improves night vision and plays a part in our immune system. Carrots also contain a substance called carotenoids. These plant pigments give carrots their bright colour and are powerful antioxidants. Some studies suggest that a diet high in carotenoids may particularly help reduce the risk of certain cancers, including prostate and breast cancer.

Further reading

Swiss chard

Swiss chard (snijbiet in Dutch, blette in French) is another hardy winter vegetable that packs a lot of nutrients. It is also very low in calories: a helping of 36 grams contains just 7 calories but also half the daily recommended intake of vitamin A and all of that for vitamin K. It is also a good source of vitamin C, magnesium and manganese. And again, the compounds that add colour to these vegetables are also the ones who provide great benefits. In the case of Swiss chard these are known as betalains. Betalains have been shown to reduce inflammation in the body and decrease the oxidation of LDL cholesterol, one of the main causes of heart disease.

Further reading

Parsnips

Parsnips are somewhat of an oldfashioned vegetable, that has recently become more popular. As the name somewhat indicates, parsnips are basically the root tubers of parsley. Looking a bit like white carrots, parsnips are another kind of root vegetable with a host of unique health benefits. Like carrots, parsnips grow sweeter as frigid temperatures set in, making them a delightful addition to winter dishes. They have a slightly earthy taste and are highly nutritious and very rich in fibres as well as vitamins B, C and E, potassium, magnesium and manganese. Soluble fibres are especially beneficial and not just for diabetes patients. Soluble fibres are different from insoluble fibres (that come from products like whole grains) and aid our digestion in a different manner. A diet rich in soluble fibres has been linked to a reduced risk of heart disease, breast cancer and stroke.

Further reading

Collard Greens

Collard greens are a lesser known member of the brassica group of vegetables. It is commonly used in Chinese cuisine and can be described as a no-frills kale. And like kale, collard greens are among the most cold-hardy plants of the group. This slightly bitter green can withstand prolonged sub-zero temperatures and tastes best after being exposed to frost. That bitter taste is the result of the high calcium content of collard greens. Just 190 grammes contains 27% of all the calcium you need in one day. Calcium is essential for bone health, muscle contraction and nerve transmission, along with other important functions. Collard greens also have a high vitamin K content, and the combination of vitamin K and calcium indicates that collard greens are very beneficial for bone health. On top of this, collard greens also contain vitamin B and C, iron, magnesium and manganese.

Further reading

Turnips

Turnips are another oldfashioned vegetable that have recently enjoyed a rise in popularity. These root vegetables grow best in cold weather and as temperatures turn colder in the fall and winter they store more sugar and become more flavoursome. Turnips contain large amounts of vitamin C and potassium, as well as vitamin B, magnesium, phosphorous and manganese. Potassium is crucial for heart function and muscle contraction. It also plays a key role in controlling blood pressure. Certain studies have shown that a diet rich in potassium may help reduce high blood pressure. Subsequently, observational studies have linked cruciferous vegetables like turnips to a lower risk of heart disease. One study found that eating more cruciferous vegetables could reduce the risk of developing heart disease by almost 16%.

Further reading

Red cabbage

Red cabbage is the most nutritious cabbage out there, much healthier than its green and white cousins. Not only does red cabbage contain a large amount of vitamin C, A, B and K as well as potassium and manganese, but red cabbage is also full of antioxidants. And as in other vegetables in this list, it is the compound that causes the cabbage’s colour that is the cause. In red cabbage these pigments are known as anthocyanins, and they are the same pigments that also add blueberries their distinctive colour. They belong to the flavonoid family of antioxidants, which have been linked to a number of health benefits. One of these benefits is the potential to reduce the risk of heart disease. A diet rich in anthocyanins has also been found to reduce the risk of coronary artery disease. Furthermore, test-tube and animal studies suggest that anthocyanins may have cancer-fighting abilities as well.

Further reading

Radishes

Radishes are mostly considered a summer vegetable and are often used in salads. But like its big brother the turnip, radishes can be very cold-hardy and survive freezing temperatures. And just like turnips, radishes belong to the cruciferous plants, and we already know that these come with a range of health benefits. Radishes are rich in vitamins B and C, as well as potassium. It is their peppery taste, however, that makes them extra healthy. This taste comes from sulfur-containing compounds called isothiocyanates, which have been linked to many health benefits. They act as antioxidants in the body, helping keep inflammation in check. Radishes have been extensively researched for their potential cancer-fighting properties, specifically regarding breast cancer, colon cancer and bladder cancer. So far these studies have only involved test tube cells and animals, so human studies are needed in order to establish whether isothiocynates can actually play a part in the prevention and treatment of cancer.

Further reading

Parsley

The green part of the parsnip is just as healthy as the white underground part. Parsley is one of the few kitchen herbs that continue to grow even in winter, when most leafy herbs die down. The aromatic leaves are just as nutritious as the white tubers. Parsley leaves –whether flat or curly- contain a lot of vitamin K and C. It’s also loaded with vitamin A, folate, iron, calcium and potassium. And yes, parsley also contains flavonoids, in this case apigenin and luteolin, which are plant compounds that have many potential health benefits. These flavonoids may be particularly helpful in inhibiting memory loss and age-related changes in the brain. One study found that a diet rich in luteolin reduced age-related inflammation in the brain of aged mice and improved memory by inhibiting inflammatory compounds.

Further reading

To conclude: eating vegetables is always a very healthy and tasty option, in winter just as much as in summer. And many winter vegetables bring health benefits that science is only just beginning to understand.

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