WHY A COLOURFUL DIET IS GOOD FOR YOU
By Sally Shi-po POON (Registered Dietitian)
We’re always hearing that we should “eat the rainbow”, but what does that mean and why is a colourful diet so highly recommended by dietitians all over the world? Not only are they appealing, the phytochemicals that give foods their colour are packed with nutritional benefits. I have grouped the foods into 5 categories according to their predominant phytochemical group: red, orange, green, purple, and white.
Lycopene is the predominant pigment in red fruits and vegetables such as tomatoes, watermelon and pink grapefruits. It is a powerful antioxidant that may help prevent prostate cancer and heart diseases. Lycopene is better absorbed when it is cooked with some oil, such as tomato sauce with olive oil.
Astaxanthin, which is found in the red pigment of crab, salmon and prawns, has been found to have antioxidant and anti-inflammatory effects. Its antioxidant activity was found to be 10 times more than zeaxanthin, lutein and beta-carotene.
Beta-carotene is a pigment found in yellow and orange fruits and vegetables, such as carrot, cantaloupe melon, mangoes, orange peppers, pumpkin, and sweet potatoes. In the body, beta-carotene converts into vitamin A, which is needed for good vision, a strong immune system, and healthy skin. Food processing and cooking help release beta-carotene from the food matrix and make it easier to absorb. Moreover, its absorption requires the presence of fat in a meal, such as canola oil, almonds, flaxseed or pumpkin seeds.
Green cruciferous vegetables such as broccoli, cabbage, brussel sprouts, and kale are good sources of sulforaphane and glucosinolate, which have antioxidant and anti-inflammatory properties. These vegetables also contain lutein and zeaxanthin, which may help protect eyes from sunlight damage and reduce the risk of cataracts and age-related macular degeneration. Lutein and zeaxanthin are better absorbed with fats, so be sure to eat the vegetables with some avocado, cheese, walnuts, sunflower seeds or olive oil. Green vegetables are also excellent sources of vitamin K and folic acid. Folic acid helps prevent neural tube defects during pregnancy, and vitamin K plays a major role in blood clotting.
Anthocyanins are pigments that appear purple or blue, which are found in eggplant (especially the skin), blueberries, blackberries, prunes, plums, black rice, purple sweet potato, and purple cauliflower. The darker the colour, the higher the anthocyanins concentration. Boiling vegetables can increase the loss of water-soluble nutrients such as anthocyanins and vitamin C, therefore baking and steaming are preferred as they can retain more of the nutrients, as well as the flavour and colour.
Anthoxanthins are the white or colourless pigments found in bananas, cauliflower, garlic, shallots, mushrooms, onions, parsnips, and turnips, which may help reduce the risk of heart disease. Garlic contains allicin, which has antioxidant, anti-inflammatory, antimicrobial, and heart-protective properties. Allicin is produced when fresh garlic is finely chopped or crushed. Garlic provides an alternative to salt in cooking, along with other herbs and spices. Eating less salt is important for preventing high blood pressure, heart attacks and stroke.
Including a variety of colourful foods in your diet seems to equal better overall health. Start planning some colourful recipes tonight and have a healthy start in 2018!
Sally’s Nutrition Blog @ Hong Kong Tatler: https://hk.asiatatler.com/life/why-a-colourful-diet-is-good-for-you#page-1