China: Veggies warned of health food hazards

If you thought becoming a vegetarian would end your nightmares about bird flu, foot-and-mouth disease, Sudan red dye in eggs or even fish contaminated with malachite green, then think again.

And if you are one of those health conscious people who enjoys a sprinkling of flaxseeds on your morning cereal, you could end up suffering from cyanide poisoning. According to risk assessment research officer Dr Anna Tang Chi-ping from the Centre for Food Safety, at worse you will go into a terminal coma, and suffer from headaches, dizziness, mental confusion and stupor along the way.

"Flaxseeds contain the chemical compound cyanogenic glycoside which, in the presence of water, will release toxic hydrogen cyanide into the digestive system," Tang said Tuesday. Flaxseeds have a smooth, shiny, reddish-brown appearance, and are prized by the health-conscious due to their high Omega-3 fatty acid content.

Flaxseeds are usually sprinkled on cereal, salads and desserts or as an added ingredient when making bread to boost the nutritional content. However, Tang warned that the seeds also contain a natural toxin and therefore daily consumption should not exceed more than three tablespoons. "Moderation is the key," she said.

The natural toxin found in flaxseeds can also be found in bitter apricot seeds, bamboo shoots and cassava, with releasable cyanide levels ranging from 9.3 to 330 mg/kg, according to the CFS. According to the World Health Organization's International Program on Chemical Safety, 50-60 mg/kg of cyanogenic glycosides constitutes a lethal dose for an adult male.

Tang suggested cutting the cyanogenic food into small pieces and cooking it in boiling water for 15 to 20 minutes to reduce the toxins by more than 90 percent.

"Hydrogen cyanide is volatile, and can easily be removed by open-lid cooking," she said, adding that dry-heat cooking, such as baking and frying will not reduce the cyanide content in food effectively.

The CFS also warned against consuming potatoes that are beginning to sprout roots as these contain 7,600 mg/ kg of another natural toxin - glycoalkaloid - which far exceeds the normal daily consumption level of the 20 to 100 mg/kg recommended by the WHO's Expert Committee on Food Additives.

Tang said although the toxins are concentrated in the potato peel rather than the flesh, the whole potato should not be consumed.

The CFS also warned against the natural toxins present in other commonly consumed beans and vegetables, such as green beans, red kidney beans, white kidney beans, soyabeans, ginkgo biloba, cabbage, cauliflower, broccoli, mustard and turnips.

"They should be cooked thoroughly to guard against the natural toxins," Tang said. Certain fish also contains natural toxins. Consumers should properly refrigerate fish that may contain histamine toxin - such as tuna, mackerel, sardine and anchovy - at four degrees Celsius or below.

The CFS said consumers should avoid purchasing puffer fish and porcupine fish, which contain tetrodotoxin, and eat fewer coral reef fish, which contain ciguatoxin, especially when drinking alcoholic beverages or consuming nut or seed products.

From 2004 to 2006, the CFS recorded 430 incidents of people falling ill after consuming fish tainted with ciguatoxin, 12 after eating tetrodotoxin- tainted fish and 20 from histamine- tainted fish poisoning.

Source: thestandard.com.hk