Most people know that they should eat more fruit and vegetables, yet time and time again surveys reveal that intakes of this food group are well below recommended levels – from national food surveys such as the North/South Food Consumption Survey to independent market research, the fact that Irish people in general do not eat enough fresh fruit and vegetables is confirmed.

Recommended intake

The amount of fruit and vegetables recommended for health is four or more portions a day and you can choose from fresh, frozen, tinned, dried or juiced varieties. Remember that potatoes are not part of the vegetable group. They belong to the energy-rich cereal group, whereas fruit and vegetables are one shelf up from potatoes on the food pyramid. And just in case you did a double take on reading that dried foods count, yes, dried fruit such as mango, raisons, dates, apricots and figs are very nutritious.

A portion of fruit and vegetables

A portion from the fruit and vegetable group is 80g or any of the following:

• 1 apple, pear, orange, banana or similar sized fruit
• 2 plums or kiwifruit
• Half a grapefruit or avocado
• 1 slice of large fruit such as pineapple or melon
• 3 heaped tablespoons of beans or pulses
• 3 heaped tablespoons of vegetables whether raw, cooked, canned or frozen
• 3 heaped tablespoons of fruit salad whether tinned or fresh
• 1 cupful of cherries, berries or grapes
• 1 heaped tablespoon of dried fruit such as apricots or dates
• A glass (150ml) of fruit juice (however much you drink, fruit juice can only count as a maximum of 1 portion per day)

Disease prevention

There is good evidence that eating lots of fruit and vegetables means that we are less likely to develop diseases such as heart disease and some types of cancer. The main nutrients in fruit and vegetables are vitamin C, folates, fibre and some carbohydrate.

Whereas the vitamin and fibre content of fruit and vegetables is widely known, the new language of nutrition includes terms such as phytonutrients, lycopene and plant sterols, which are also found in fruit and vegetables.

Phytonutrients

Phytonutrients are the non-nutritive components of fruit and vegetables and they are thought to have beneficial health effects. One example is the polyphenolic compounds found in grapes. It has been suggested that these help to confer a protective effect on heart health to those who drink moderate amounts of red wine.

However, this may well be wishful thinking as there is no evidence yet that a particular nutrient or bioactive substance makes a special contribution to health. Although studies have observed beneficial health effects in those who eat a diet rich in fruit and vegetables, there is little understanding of how this is achieved.

Lycopene

Lycopene is the new 'antioxidant' on the block and it follows in the footsteps of vitamins A, C and E. Antioxidants protect blood vessels from internal damage caused by free radicals and while some of this rough and tumble within vessels is a form of communication between cells, it can also result in damage and can set the scene for heart disease.

Lycopene is found in tomatoes, pink grapefruit and watermelon. Cooked tomatoes such as ketchup, tomato sauce and tomato puree are particularly good sources of lycopene.

Plant sterols and stanols

Plant sterols and stanols are derived from edible vegetable oils. They are the new functional foods designed to lower cholesterol, and have been incorporated into foods such as yoghurt, margarine, cheese and milk. They work across all cholesterol levels and can bring about a reduction in cholesterol of about 10%. This can be very helpful in protecting against heart disease.

Folic acid

The B vitamin folic acid is well known for its beneficial effects on reducing the devastating birth defects that are caused when the neural plate fails to close correctly around the 10th or 12th day of pregnancy.

Most women do not even realise that they are pregnant at this stage and when their pregnancy is confirmed two to three weeks later it is too late to correct a low folate level, and anencephaly and spina bifida can result.

Most children with anencephaly only survive for a few days after birth, and spina bifida can cause a variety of physical and intellectual defects. Folic acid taken before conception can reduce the number of babies born with these defects from eight a month to just one. Therefore, a folic acid supplement is recommended for all women who are planning a pregnancy.

Folic acid also has a powerful effect on heart health. It is involved in the intricate pathways of protein metabolism. It helps to lower homocysteine. A raised homocysteine level is now recognised as an independent risk factor for heart disease. This means that it is as important to lower homocysteine as it is to lower cholesterol.

Folic acid is found in dark green leafy vegetables such as spinach and broccoli. However, the synthetic form of folic acid is more easily absorbed by the body than the natural form of the vitamin and so, although it is a real exception when nutritionists recommend a vitamin supplement over food for its beneficial effects, a folic acid supplement is recommended, particularly in pre-pregnancy.

Vitamin C

Although vitamin C cannot cure the common cold, studies suggest that it can shorten its course by about 20%. That can mean getting back on your feet one day earlier. To the elite athlete, champion golfer or club camogie player this could be critical.

Vitamin C is especially important for those involved in sport whose immunity is impaired for a short period after strenuous exercise. This in turn makes them more susceptible to colds and flu. Vitamin C-rich foods include citrus fruits like oranges, lemons, grapefruit and limes.

Energy density

There is a lot of emphasis on the growing problem of obesity in children and adults in Ireland. Bringing down the energy density of the diet will play an important role in the reversal of this problem. Foods that help to lower the total amount of calories eaten, yet fill appetites with healthy calories and are full of vitamins and minerals are key.

Examples of foods that are low in energy yet high in nutrition are fruit and vegetables, wheat, oats, rice and barley. Getting the energy density of our diet correct will be vital in the fight against obesity and overweight.