Although it doesn't taste of anything by itself, MSG can stimulate the taste buds and enhance the flavour of foods.

Scientists think MSG elicits a taste that is known as 'umami' in Japanese and which is often described as savoury or meaty. Umami can be considered the fifth basic taste - the other four are salty, sweet, sour and bitter.

The main component of MSG is glutamate, an amino acid which occurs naturally in meat, fish, cheese, peas, corn, mushrooms, tomatoes and seaweed.

Less is more when it comes to using MSG. Once the proper amount is used, adding more doesn't give food any more flavour; in fact, the opposite is true as it makes food taste unpleasant.

Over the past 40 years, MSG has become a controversial ingredient because of reports of adverse reactions in people who have eaten foods containing MSG.

'Chinese Restaurant syndrome' was first reported in 1968 after a restaurant customer reported numbness at the back of the neck spreading to the arms, general weakness and heart palpitations after eating at a Chinese restaurant.

A comprehensive review of scientific data on the safety of MSG was conducted by the US Food and Drug Administration in 1995. The review didn't find any evidence to suggest MSG contributed to long-term health problems when eaten at levels typically used in cooking and food manufacturing.

However, the report concluded some people may be more sensitive to MSG and may experience short-term side effects such as headache, flushing, sweating, facial pressure, numbness or burning around the mouth, chest pain, shortness of breath, nausea and weakness.

Those suffering from MSG intolerance may also react to 'free' glutamate that's been added to foods - naturally-occurring glutamate is bound to proteins, rather than being 'free', so doesn't pose any problems. The only way to prevent a reaction is to avoid foods containing MSG or glutamate.

But this can be a difficult task since MSG and glutamate are often added to processed foods, and restaurants often use MSG. But don't let that put you off: ask before you order at restaurants and scrutinise the ingredients on food labels.

Look out for the following on labels - they mean the food contains MSG or free glutamate:

Monosodium glutamate; monopotassium glutamate; glutamate; glutamic acid; yeast extract; autolysed yeast; hydrolysed protein; hydrolysed corn gluten; natrium glutamate; calcium caseinate; gelatin; textured vegetable protein

Breakfast: Slice of buttered toast, milk

Lunch: Noodles or pasta

Dinner: Rice, vegetables and a meat dish

Snacks: Fruits and water

Exercise: Karate once a week, jazz funk dance once a week, jogging at the weekends