Antioxidants

Natures secret ingredient in fruit and vegetables

Many people in New Zealand and Australia struggle to eat the recommended amounts of fruits and vegetables each day.
There are a variety of reasons why people may not eat enough fruits and vegetables. However, there is convincing evidence that a diet rich in fruits and vegetables can be protective against:

  • Cancer 
  •  Coronary heart disease 
  •  Stroke

There is also increasing scientific evidence that fruit and vegetables may play a role in preventing cataracts, diverticular disease, high blood pressure and types of chronic obstructive pulmonary disease including asthma and bronchitis.
A further benefit of enjoying more fruits and vegetables is that they could help displace foods high in saturated fats, sugar and salt in your diet. Most fruits and vegetables are filling, but generally low in energy density - meaning kilojoules. This is very useful for people wanting to manage their weight.
In fact, along with high blood pressure, high cholesterol, obesity and physical inactivity, inadequate levels of fruit and vegetables has been identified by the World Health Organisation as one of the major causes of chronic diseases. Worldwide, a low intake of fruit and vegetables is estimated to be responsible for about 19 per cent of gastrointestinal cancer, about 31 per cent of ischemic heart disease and 11 per cent of stroke.

Why are fruits and vegetables so good?

Not only do fruits and vegetables contain plenty of vitamins, minerals and fibre, there is something else about fruits and vegetables that makes them special - they are abundant in antioxidants.

What is an antioxidant?

Antioxidants are chemicals, (phytochemicals - pronounced 'fight-o-chemicals') often found naturally in plant foods, that can help protect our body cells from being damaged by 'free radicals'. Free radicals are produced both naturally in our body and due to exposure to pollutants and result in cell damage. Antioxidants can therefore guard against cancer and heart disease, as well as diseases of the eye - all of which can be influenced by damaged body cells. The role of antioxidants in the prevention and treatment of a number of other conditions is also being investigated. It is the phytochemicals that give fruits and vegetables their distinctive colours and smells.
We generally classify fruit and vegetables into five colour groups, according to the phytochemicals they contain - green, yellow/orange, red, blue/purple and white/brown. There are many different phytochemicals that work together to protect your health. You will probably find that some have quite unusual names but don't let this deter you from finding out about their unique health benefits. To ensure you receive a great variety of phytochemicals in your diet, choose fruits and vegetables from each of the colour groups every day.

Red foods

The phytochemicals lycopene, ellagic acid and a flavonoid called kaempferol contribute to the special features of red fruit and vegetables.

Red foods include:
- tomatoes
- red capsicum
- radishes
- strawberries
- rhubarb
- cherries
- red grapes
- raspberries
These phytochemicals act as antioxidants, can be cancer protective and can also help reduce the risk of heart disease. Lycopene is a powerful antioxidant belonging to the group of carotenoids. A high intake of lycopene in particular has been linked with a reduced risk of prostate cancer.

Purple/blue foods

The colour in purple/blue fruits and vegetables is mainly due to the flavonoids, anthocyanins, which are powerful antioxidants and have a mild anti-bacterial effect. Another phytochemical discovered in this group of fruits and vegetables includes resveratrol, which is most commonly found in grapes and may have a cancer protective effect.
Purple/blue foods include:
- beetroot
- purple asparagus
- red cabbage
- eggplant
- blackberries
- blueberries
- purple grapes


Orange/yellow foods

There are abundant antioxidants in yellow and orange fruit and vegetables, including the carotenoids (beta-carotene, lutein, zeaxanthin), which give this group their bright colour. A wide range of other phytochemicals including terpenes and flavonoids (quercetin) also occur in this group.
Orange/yellow foods include:
- carrots
- pumpkin
- corn
- kumara
- rockmelon
- lemons
- mangoes
- pineapples
- oranges
Carotenoids, terpenes and flavonoids act as antioxidants to protect against cancer and heart disease. Of interest is lutein (pronounced 'loo-teen'),which is a carotenoid that is stored in the eye. This is important to help prevent two of the most common causes of blindness, cataracts and age-related macular degeneration.

Green foods

Like orange/yellow foods, green fruits and vegetables are particularly rich in antioxidants. They include varying amounts of many phytochemicals including flavonoids and carotenoids (lutein, beta-carotene and zeaxanthin). The Brassica group (broccoli, cabbage, Brussels sprouts) also contains indoles, which can trigger enzymes to act against certain cancer causing substances. Saponins, another phytochemical found in green plant foods, also have anti-cancer properties. They interfere with the process whereby cancer cells multiply.
Green foods include:
- spinach
- broccoli
- asparagus
- peas
- avocadoes
- green apples
- green grapes
- limes
- kiwifruit
-green pears

White/brown foods

While these colours are not as vibrant as the other colour groups, we should not underestimate the nutritional contribution that brown/white fruit and vegetables can make to our diet.
Brown/white foods include:
- cauliflower
- garlic
- ginger
- mushrooms
- onions
- potatoes
- bananas
- brown pears
- white peaches and nectarines
- dates
Fruits and vegetables from this group contain phytochemicals including allicin, indoles and isothiocyanates, to name just a few! Many of the phytochemicals found in this group of foods have effects ranging from anti-bacterial, anti-viral and anti-cancer, to the prevention of heart disease. This knowledge goes some way to understanding the long held belief that garlic is good for you.

Promoting fruit and vegetable consumption around the world.

Programmes are being conducted around the world to encourage people to enjoy fresh fruits and vegetables. We need to eat MORE fruits and vegetables.
New Zealand has a 5+a day/ The Colour Way initiative. 5+a day means enjoy 5 or more servings of fresh fruits and vegetables each day. A serving is about a handful and is relative to age and size. Visit www.5aday.co.nz  for more information

How many serves did you have yesterday?

Here is a guide to define a serve of fruit and vegetables: 

  • 1/2 cup cooked vegetables 
  •  1/2 cup salad vegetables 
  •  1/2 cup cooked beans, peas or lentils 
  •  1 medium potato or kumara 
  •  1 piece of medium sized fruit (apple, orange, pear) 
  •  8 strawberries 
  •  1 cup diced fresh or canned fruit 
  •  2 pieces smaller fruit (apricots, plums, kiwi fruit) 
  •  4 dried apricots 
  •  1 1/2 tablespoons sultanas 
  •  1 cup fruit juice
    *Based on the Food and Nutrition Guidelines for Healthy Adults: A Background Paper, MOH, 2003.

    Great fruit and vegetable ideas:

    If you didn't reach your fruit and veggie goal yesterday, here are a few ideas that may help to inspire you for the days ahead:
  • Swap the bacon and eggs at your weekend breakfast for baked beans or grilled mushrooms and tomato on wholegrain toast. 
  • Include vegetables, such as baby spinach in pasta sauces and risottos. Stir through at the end of cooking, for a little extra colour and nutrition. 
  • Make salads substantial, with more than just lettuce. Try adding baby spinach, rocket, lightly steamed broccoli, red capsicum, tomato and roast kumara. Toss through a can of rinsed and drained beans (such as butterbeans or chickpeas) for extra protein. 
  • Pack a fruit salad for morning tea. Try to include all the colour groups. 
  • Have a salad or some salad vegetables on your sandwich for lunch. 
  • Try to have at least four different colours of vegetables, grains and legumes on your plate each evening. 
  • A stir-fry with lots of vegetables is another great way of including a variety of colours at your evening meal. 
  • Kids love frozen oranges, bananas, grapes and strawberries for an icy summer treat. 
  • Grate or dice onion, carrot, courgette, red capsicum and corn into a savoury muffin or pikelet mixture. 
  • Have vegetable sticks such as carrot and celery on hand for a healthy snack. Vegetable sticks dipped in hummus or tomato salsa are delicious and very filling. 
  • Enjoy a fruit-based dessert rather than cakes and puddings. 
  • Dried fruit also makes an easy, to-go snack. Just add a handful into some plastic wrap and pop into your bag.

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