Five healthy white or colourless foods that belong in your diet

We’re told to choose our foods by colour. Good advice, since the darker and brighter the colour, the more nutrients and phytochemicals are packed inside.

Blueberries and raspberries, for instance, owe their deep blue and red hues to anthocyanins, powerful compounds thought to guard against cardiovascular disease and cancer and boost cognitive function.

Brightly coloured orange and green vegetables, such as spinach and carrots, are exceptional sources of beta-carotene, an antioxidant that protects cells from free radical damage.

Brown rice, which hasn’t been stripped of its nutrient-rich bran and germ layers, has considerably more fibre, magnesium and potassium than white rice. (White rice has been enriched with B vitamins and iron, nutrients lost during processing.)

Indeed, we’ve been conditioned to avoid the white stuff – white sugar, white flour, white rice and so on. Compared to their unprocessed counterparts, colourless foods are missing fibre and protective phytochemicals and they’re a poor source of many nutrients.

And many score high on the glycemic index scale, meaning that their carbohydrates are broken down and absorbed quickly, causing blood sugar and insulin to rise rapidly. A diet based on high-glycemic foods is thought to contribute to insulin resistance, a precursor to Type 2 diabetes.

Even so, this doesn’t mean you should nix all white foods from your diet. Despite their pale colour, some are surprisingly plentiful in vitamins, minerals and beneficial plant compounds.

Here are five nutritious white foods that deserve a place on your menu.

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Mushrooms

For a food that lacks colour, mushrooms deliver plenty on the nutrition front. One cup of raw whole mushrooms (about 10 small or 5 medium) provides 20 per cent to 25 per cent of a day’s worth of niacin, a B vitamin that’s used to make stress hormones, improve circulation and reduce inflammation. Not bad for 21 calories. One cup even serves up 3 grams of protein.

Mushrooms are also an excellent source of selenium, a mineral that acts as an antioxidant, helps make DNA and plays an important role in thyroid function. And they supply potassium, copper and iron.

Add mushrooms to salads, soups, pasta sauces, whole grain pilafs, stir-fries and crudité. Or, enjoy them as a side dish sautéed with a splash of balsamic vinegar.

Parsnips

Despite the fact that this root vegetable has very little pigmentation, it's not without disease-fighting phytochemicals or nutrients.

Parsnips are packed with falcarinol, a phytochemical with anti-inflammatory and anti-cancer properties. Animal research suggests that falcarinol may reduce the growth of colon cancer cells. Parsnips contain five times more falcarinol than brightly coloured carrots.

Parsnips are also nutrient-dense. One cup of cooked parsnip, for example, serves up 5.5 g of fibre, 572 mg of potassium, 20 mg of vitamin C and almost one-quarter of a day's worth of folate.

Enjoy parsnips roasted with herbs or cooked and mashed with other root vegetables such as carrot, turnip or sweet potato.

Or, make parsnip chips. Slice parsnips thinly, brush with olive oil and bake until crisp.

Bananas

There’s more to bananas than their high in potassium content (422 mg per one medium banana).

They're also an exceptional source of B6, a vitamin that's needed for protein metabolism and to maintain healthy nerve and brain function. One medium banana supplies one-third of a day's worth of the nutrient for adults aged 19 to 50, and 25 per cent of a day's worth for older adults.

Bananas also provide fibre, vitamin C, folate, niacin and magnesium. And contrary to popular belief, bananas have a low glycemic index value of 51 (GI values less than 55 are considered low).

And thanks to their resistant starch, bananas are considered a prebiotic, a food that feeds beneficial gut bacteria.

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Potato

Often regarded as a starchy food with little nutritional value, the white potato is surprisingly nutritious. One medium baked potato serves up 22 milligrams of vitamin C along with plenty of B6, folate and magnesium.

Its claim to fame, though, is its hefty potassium content. A medium potato, for instance, delivers 941 mg of the blood-pressure-regulating mineral, 20 per cent of a day's worth.

Potatoes can help ward off hunger, too. According to researchers from the University of Sydney, boiled white potatoes scored highest on the satiety index, a tool that ranks foods by their ability to satisfy hunger. Researchers tested 38 different foods, including breads, breakfast cereals, grains, fruits, protein-rich foods and snack foods.

Some varieties of white potato do have a high glycemic index (GI). Russet potatoes do, but red and new potatoes have moderate GI scores.

The glycemic index of potatoes also depends on how you cook them.

Eaten cold (precooked) or reheated, potatoes have low to moderate GI value. Cooling cooked potato starch changes its structure making it resistant to digestion in the small intestine.

Leave the skin on when you cook potatoes. It contains fibre and nutrients, and it helps retain the vitamin C in potatoes.

Onions

This vegetable does more than add flavour to meals. It also provides a little vitamin C, folate, calcium and potassium.

Onions are high in flavonols, phytochemicals that neutralize harmful free radicals and suppress inflammation. One particular flavonol, called quercetin, has been linked to protection from lung cancer, asthma and diabetes.

Observational research suggests that a moderate intake of onions may reduce the risk of colorectal, laryngeal and ovarian cancers.

Organosulfur compounds in onions, the same chemicals that give onions their distinctive flavour, have also been shown to have anti-bacterial, anti-cancer and cholesterol- and blood-pressure-lowering properties.

Leslie Beck, a registered dietitian, is based at the Medisys clinic in Toronto.