What do Nicole Kidman, Halle Berry, Charlize Theron and closer to home - Fann Wong - have in common?

Apart from being well-known actresses, they have absolutely gorgeous skin which seems to glow from within.

The secret to such perfect skin lies in vitamin A, says South African plastic surgeon, Dr Des Fernandes.

'Vitamin A is responsible for regulating the health of thousands of genes in cells. The antioxidant properties neutralise harmful elements in our skin, helping to prevent wrinkles, resist infection and keep skin youthful,' he said.

Vitamin A is a fat-soluble vitamin that can be obtained from either animal or vegetable sources.

They include eggs, meat, and coloured fruit and vegetables.

'If there is insufficient vitamin A in the skin, it will not renew itself as fast, resulting in pigmentation, wrinkles and worst - skin cancer,' said Dr Fernandes, who has treated stars such as Gwyneth Paltrow and Madonna.

The problem is vitamin A is destroyed by exposure to light, particularly sunlight.

'Spend 20 minutes in the sun and your level of vitamin A will drop 80 to 90 per cent,' Dr Fernandes said.

His advice is to make vitamin A part of the daily skin-care routine for everyone who is exposed to sunlight - from sun-babies to construction workers. And wear a good sunblock.

The answer is not to avoid the sun altogether, said Dr Fernandes. That creates its own problems.

'Sunlight is needed to make vitamin D, which is necessary for bone health, to prevent osteoporosis,' he explained.

Vitamin D is produced by the skin when exposed to ultraviolet radiation from sunlight.

Addressing vitamin A losses

Replacing vitamin A lost every time we go out into sunlight can be done through the diet or a topical cream.

'We need to replenish that vitamin A every day but we can't rely solely on diet,' he said.

He said it would take weeks to restore the level of vitamin A lost to sunlight in 20 minutes, through the diet.

'But applying a topical cream fortified with vitamin A can restore it in just three hours,' he added.

Dr Cheong Lai Leng, a dermatologist in private practice, agrees that it is true 'you can never eat enough vitamin A to get the same effect as topical cream', but a good balanced diet should replace the amount of vitamin A lost to sunlight.

'That is, if you don't subject yourself to strong sunlight over long periods,' she said.

Doctors say the use of vitamin A creams can have side effects and signs to watch out for include redness, a stinging sensation, peeling and increased sunburn potential.

Plastic surgeon Ivor Lim said it makes the skin fairly sensitive and dry.

'Those sold off the counter are usually weak formulations. If consumers want higher strength creams, then they should get a prescription from the doctor and be monitored so that there would not be any adverse effects,' he advised.

juditht@sph.com.sg