WITH the current fashion for slimness, encouraged by pop stars and models, latest government figures show that one in six girls aged 15-18 are dieting to lose weight.

However, according to supplement experts, the Health Supplements Information Service (HSIS), while our teenagers pursue the quest for the perfect 'supermodel' body, many are also starving themselves of vital nutrients needed for growth and development.

A teenager's body carries on growing until around 18 years of age and because of this, energy requirements are higher during teenage years than from age 20 and over.

The most important nutrients required by a growing teenager are iron, calcium, B group vitamins, vitamin C, essential fatty acids of the omega-3 and omega-6 series, magnesium and vitamin D.

Diets that are deficient in these nutrients can lead to a whole host of problems from fatigue, muscle weakness, anaemia and skin conditions, to compromised bone strength and development which could lead to complications, such as osteoporosis in later life.

Commenting on teenage weight-loss programmes, Dr Margaret Ashwell OBE, chair of the HSIS advisory panel, says: "Faddy diets often mean major food groups are cut down or missed out.

"A diet followed properly should still contain a range of balanced foods to ensure adequate intake of essential vitamins and minerals.

"Health supplements are not a substitute for a healthy diet but can act as an insurance policy to ensure sufficient vitamins and minerals are taken in."

To ensure that vital nutrients are being consumed, HSIS has compiled the following healthy eating tips for teenagers.

l There's no harm in cutting out fatty, fast or convenience foods which have a low nutritional content, but they must be replaced with healthy alternatives like pasta, rice or wholemeal bread.

l Never let yourself feel too hungry - always eat three healthy, balanced meals a day, including five portions of fruit and vegetables.

l Although there is no substitute for a healthy, balanced diet, taking a multivitamin and mineral supplement can help guard against micronutrient deficiencies. Teenage requirements are either similar to those of an adult, or slightly higher, so it is safe to take adult supplements.

l Dieters should try to eat oily fish twice a week. If this is not possible, you should take a daily supplement of fish oils or cod liver oil to maintain your intake of omega-3 fatty acids.

l If dairy products are cut out of the diet a supplement of calcium is important.

l Regular exercise, around 20 minutes a day, is essential in helping weight loss.

l Finally, if a teenager really wants to lose weight they should first seek advice from their doctor.