Winter greens

Summer may play host to the sweet and colourful pop stars of produce, but winter's dark and earthy greens are the gritty rock stars of the nutrition world.

Spinach, cabbage, broccoli, Brussels sprouts and silverbeet are ubiquitous in the produce aisle, but some of the lesser known winter greens include chicory, kale, mustard greens, collards, turnip greens, escarole and rapini.

Brussels sprouts have come into fashion in their own right. They offer a hefty dose of indole-3-carbinol - a chemical that has been studied for its anti-cancer properties - along with fibre, calcium and vitamin C.

Turnip greens boast high lutein content - needed for healthy eyes - and are an excellent source of calcium, folate and vitamin K, A and C. They also contain some protein and omega-3 fats. Likewise, kale, with its unruly leaves and bitter reputation, is a nutrient powerhouse.

The darker side of leafy greens

While these ‘super' foods offer great health benefts, they do often taste bitter and have a tough fibrous structure. Some of these winter greens also contain small amounts of natural plant toxins or ‘antinutrients'. Goitrogens - found in members of the brassica family, such as kale, cabbage, broccoli and Brussels sprouts - are chemicals that (especially when raw) can suppress thyroid function. Spinach and silverbeet are high in oxalates, too, which can bind to certain minerals in the body and inhibit nutrient absorption. Antioxidants such as carotenes - found in large quantities in dark leaves - are essential in small doses, but harmful to the liver when consumed in abundance.

The nutritional trade-off is mostly tilted in our favour, however, meaning we reap more benefits from the cumulative nutrition of these foods than there are downsides. This can be stacked further to our advantage simply by cooking and consuming our greens in a suitable way.

Raw or cooked?

Light-coloured greens, such as iceberg lettuce and sugar snap peas, contain very few of these antinutrients and are naturally pleasant-tasting, so they can be consumed raw. Middle-of-the- spectrum greens, such as rocket and watercress, offer peppery bite, but are healthy in their raw state. The dark, bitter and most fibrous winter greens, such as kale and Brussels sprouts, are better for you and also much more palatable when cooked.

Raw green smoothies and juices are chock full of nutrients, but it's easy to go overboard - massive quantities of leaves can be pulverised down to almost nothing in a single serve, concentrating not only their beneficial properties but harmful ones, too. So be a little wary of mega-dosing on such unnatural volumes of greens. Even then, when consumed in more modest serving sizes, raw winter greens (in smoothies, juices and salads) aren't necessarily better for you than cooked - it's a myth that cooking destroys the nutrient content of these foods. Yes, some antioxidants such as vitamin C are sensitive to heat and water, but the digestive potential of other parts of the plant are maximised by cooking.

Getting the most from your greens

Winter greens burst with nutrients when given the right treatment. Dark winter greens stand up well to judicious amounts of salty and nutty favours - feta, speck, capers, hazelnuts or pine nuts, for example - while natural bitterness can be tempered by adding sweetness from dried currants, raisins or orange.

Nutritionally, the method of cooking is important. Steaming minimises nutrient losses and seals in the goodness. Cooking greens in soups and stews, then consuming the liquid they were cooked in, is another way to get the most from your greens. In this hearty ribollita soup, made with cavolo nero (also known as Tuscan black cabbage), beans and vegetables, all of the goodness of the braised greens and vegetables is retained, as the fortified broth becomes a star of the finished dish as well.

Fast facts:

- Winter greens are nutritional powerhouses, supplying calcium, magnesium, folate and vitamins A, K and C.

- They also contain small amounts of plant toxins that are mostly deactivated during cooking, so aim for light cooking and don't overdo it on the raw stuff.

- Cooking also helps to break down the plant fibres we can't digest properly when raw.

- Get the most out of them by cooking gently, sautéing or steaming, and by consuming the nutritious cooking liquid (as soup, for instance).

Source

Taste.com.au — August 2014 , Page 116

Author

Kate Skinner