Saturday, 8 October 2011

Medical & News: Bird's Nest & Cancer?

Swiftlets making nests
Image from birdsnestsupplier

Bird's Nest anyone?

Ages ago rumours has it that patients undergoing cancer treatments such as chemotherapy should not consume any bird's nest, but now there is evidence showing that a growth factor called Epidermal Growth Factor (EGF) exists in bird's nests [1], and because this EGF promotes the cell growth of both good and bad cells, failure to inhibit EGF increases the risk of cancer [2], which means taking more EGF (from bird's nest) will increase the risk of cancer.

You might be thinking, "Doesn't matter! How much EGF could there be?" Well, it has come into light that it is not only the EGF that is playing a part in the risk, there are other cancer-inducing compounds which can also do the job! Here's a news article from WantChinaTimes,

Hong Kong researchers reveal birds' nest contamination

  • Han Cheng-yen
  • 2011-09-25
  • 11:48 (GMT+8)
Birds' nests are some of the priciest food items in China, most frequently used in birds' nest soup. (File Photo/CFP)
Birds' nests are some of the priciest food items in China, most frequently used in birds' nest soup. (File Photo/CFP)
Scientists from Hong Kong University of Science & Technology found a cancer-inducing compound in 47 samples of edible birds' nests, but said that cooking and extended immersion in water could remove most of the chemical. Birds' nests are used for their healing properties associated with Chinese traditional medicine.
The scientists tested samples of birds' nests, primarily imported from Indonesia and Malaysia, including the common white cubilose and rare varieties such as yellow and red cubilose.
The test results showed that all of the samples contain nitrite, with some exceeding the legal limit. While Hong Kong doesn't have a standard for nitrite levels in edible birds' nests, it stipulates a maximum of 200 milligrams per kilogram for meat products. One of the red cubilose batches had amounts 31 times above the limit, at 6,400 milligrams per kilogram.
Karl Tsim, professor from the Life Sciences department at Hong Kong University, told the Shanghai Daily that nitrites were not added during production, but were natural. These nests, he believed, may be contaminated by bird excrement.
Tsim said people should not worry too much about chemicals in the nests. He said 97% of the nitrites can be removed by submerging nests in water for three to 15 hours, rinsing twice with clean water, then cooking for at least half an hour.
Michael Lam, a professor from City University of Hong Kong pointed out that although the water could wash away nitrites, long-term consumption could still destroy the function of red blood cells. He warned that if combined with acid, nitrite could lead to cancer.
Last month in Zhejiang province, red cubilose birds' nests used in a brand of soup were found to be fakes containing high levels of nitrites. The incident has led authorities in Shanghai and Hong Kong to investigate the nests, and birds' nest sales in Hong Kong have dropped 30%-50%.

Snow Ear
Image from Wikipedia
Snow Ear after cooking
Image from Food Trail
Like I always say, if you want to eat bird's nest, why not have Snow Ears (Tremella fuciformis) instead? It contains polysaccharides and definitely helps to regulate your blood sugar level and prevent you from hypoglycemia [3] and it also helps to fight bacterial infections due to its ability to inhibit quorum sensing, or the control of gene expression in response to cell density [4].

edible -- (adj) suitable or safe for eating
immersion -- (n)  [C or Uformal put something or someone completely under the surface of a liquid
cubilose -- name of a type of bird's nest
nitrite -- a chemical compund (NO2- )
stipulate -- (vb)  [T] formal to state exactly how something must be or must be done
excrement -- (n)  [U] formal the solid waste which is released from the bowels of a person or animal
hypoglycemia -- (n) low blood sugar
inhibit -- (vb) [T] to prevent someone from doing something, or to slow down a process or the growth of something


Bird's Nest @ Wikipedia

Epidermal Growth Factor @ Wikipedia

[1] Evidence that epidermal growth factor is present in swiftlet's (Collocalia) nest @ ScienceDirect

[2] Review of epidermal growth factor receptor biology @ International Journal of Radiation Oncology

Hong Kong researchers reveal birds' nest contamination @ Want China Times

Snow Ear @ Wikipedia

Hypocholesterolemia @ Wikipedia

Cytokine @ Wikipedia

[3] Polysaccharides in fungi. XXXIII. Hypoglycemic activity of an acidic polysaccharide (AC) from Tremella fuciformis]. @

Nitrite @ Wikipedia

Hypoglycemia @ Wikipedia

[4] Inhibition of Bacterial Quorum Sensing-Regulated Behaviors by Tremella fuciformis Extract @ Springer

Quorum Sensing @ Wikipedia