FOR generations parents have urged children to eat their greens. Now science has shown there is sense in the advice as vegetables such as broccoli and cabbage contain powerful antioxidants which reduce the risk of cancer and other health problems.
But why stop there? There is plenty of evidence to suggest the best way to brighten up your diet is to eat a rainbow of foods.
Building meals and snacks around a kaleidoscope of colour is a simple way to ensure you get a variety of vitamins and minerals and in many cases the plant chemicals which give fruit and vegetables their distinctive hue come with an extra health boost.
Dietitian Ursula Arens explains: “Pigments are associated with substances that have a lot of antioxidant activity. You don’t have to be too rigid, it is not an absolute rule that you should eat every colour at every meal. You don’t have to go for exotic fruits or dash across town to pick up something blue.”
Becoming more colour-conscious when it comes to meals can maximise your intake of disease-fighting nutrients and help you discover the golden health benefits at the end of the rainbow.
The plant pigment lutein is such a vibrant shade of orange it is sometimes used as a food colouring.
It is also proven to reduce the risk of macular degeneration, the most common cause of blindness in old age. A six-year study by the US National Eye Institute showed people with the highest levels of lutein in their diet have the lowest risk of blindness and macular degeneration.
Sources of lutein include squash, sweetcorn and yellow peppers and green leafy vegetables such as kale, spinach and chard.
Pumpkins aren’t just for Halloween as they deliver a powerhouse of nutrients all year round. A single serving will give four times the daily recommended intake of vitamin A and half the daily requirement of vitamin C. They are also high in the antioxidant vitamin E which when it comes from food appears to protect against cancer.
Oranges are known as a good source of vitamin C but they are also rich in folate which reduces the risk of cancer, heart disease and stroke, and vitamin A, important for vision.
Zeaxanthin, a pigment often found alongside lutein, has been shown to protect against age-related macular disease and cataracts. Korean researchers believe zeaxanthin and lutein may also slow the growth rate of bowel cancer and other tumours.
Research is at an early stage but both have been shown in laboratory tests to suppress cancer cells. The effect is strongest when they are combined as they are in foods such as green vegetables, sweetcorn and spices like paprika and saffron.
Pineapple is rich in vitamin C and a good source of manganese, a trace element important for strong bones and the prevention of osteoporosis. It may also help prevent premenstrual tension.
Lemons contain a chemical called hesperetin which suppresses the growth of cancer cells, laboratory studies have shown.
Grapefruit is high in naringenin, a plant chemical which lowers cholesterol. However it can interfere with the absorption of some medicines including cholesterol-lowering statins. Bananas are bursting with potassium which appears to reduce the risk of strokes.
Scientists at the Karolinska Institute in Sweden calculate that every daily gram of potassium in the diet reduces the odds of suffering a stroke in the following five to 14 years by 11 per cent.
A meta-analysis (a super-study which collates the findings of earlier research) has confirmed lycopene, the phytonutrient which makes tomatoes red, cuts the risk of prostate cancer by 20 per cent.Having a lot of tomatoes in the diet also appears to protect against breast and neck cancer. Earlier this year University of Portsmouth tests proved lycopene disrupts the ability of cancer cells to build the blood supply needed to fuel tumour growth and spread.
Dr Mridula Chopra, who headed the study, stressed further research is needed but says: “The important thing is for sufficient lycopene to reach where it can matter. We know that in the case of prostate tissues, it gets there.”
Heat concentrates lycopene levels so cooked tomatoes and tomato sauces have higher concentrations of it than the raw fruit.
Lycopene is also found in watermelon and pink grapefruit.
Tomatoes are also a good source of potassium which helps maintain electrical activity in the heart and counters some of the damage caused by a high-salt diet. A study in the Archives of Internal Medicine suggested increasing our daily intake of potassium to 4.7g would have the same protective impact as lowering salt consumption by 4g.
Strawberries and raspberries are good sources of vitamin C and may help reduce the risk of some cancers. Both contain ellagic acid which inhibits the growth of skin and lung cancer cells.
An Italian trial found ellagic acid also helped ease the side effects of chemotherapy.