Melbourne: Australian teenagers are being lured into buying protein powders, which are often made and distributed in unknown circumstances with mysterious ingredients, from internet, according to experts.

They are urging the consumers - including body-conscious teenage boys, gym junkies, body-builders and people trying to lose weight - to buy only reputable brands and to check all labels carefully, media reported.

This follows the NSW Food Authority's investigation last year into supplementary sports foods that led directly to the banning by the Therapeutic Goods Administration of the ingredient 1,3 dimethylamylamine (DMAA), found in some of the protein powders .

Director of enforcement and compliance at the Food Authority, Peter Day, said that it is very hard to track down the products that are not bought from store fronts.

He said that they found a number of hospital admissions of people with a very high heart rate, dizziness, and stomach ache and vomiting from the misuse of products. Risks associated with DMAA include high blood pressure, psychiatric disorders, bleeding in the brain and strokes.

Even in the absence of DMAA, some powders have been known to cause an adverse effect on health, with the British Dietetic Association saying that the high levels of additional protein over a period of time can cause kidney and liver damage.

Many of the powders contain synthetic chemicals, sugars and artificial flavourings, as well as the milk isolates or concentrates that make up the usual whey protein. As a result, a number of consumers have reported side-effects, either from the chemicals or from allergic reactions to contents of the powder.

The National Health and Medical Research Council's dietary guidelines recommend an intake of 40 to 50 grams of protein a day - the size of one piece of steak plus a wedge of cheese - but the average protein consumption in Australia is 100 grams for men, and 75 grams for women.

But Foodwatch's Catherine Saxelby doubts most people need the extra protein. According to her most people consume more than they need to. She warns this extra protein can put a lot more stress on the kidneys, breaking down the protein and flushing out nitrogen.

(Agencies)

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