A local nephrologist has sparked controversy in Taiwan by warning consumers of a possible carcinogenic risk associated with drip bag coffee, but a senior technical specialist at the Food and Drug Administration (FDA) said no such problem exists, so people need not panic.
Chiang Shou-shan (???), a former attending physician at Shin Kong Wu Ho-su Memorial Hospital in Taipei, released a warning on his Facebook page last week that drip bag coffee is normally packed in paper bags that contain wet strength agents, which he claimed are carcinogenic.
When drip bag coffee is submerged in hot water, the coffee oil will dissolve the carcinogenic chemical substance in the paper bag into the coffee brew, Chiang wrote. He urged people to be aware of the risk.
Asked about the claim, Cheng Wei-chih (???) of the FDA told CNA Sunday that a wet strength agent is a kind of high molecular polymer, which can reinforce the strength of paper coffee filters while maintaining their efficiency in filtering.
Since such agents are highly stabilized polymers, and since brewing coffee with a drip bag or paper filter only take five minutes at the most to complete, "in principle, there is no such dissolution (of the wet strength agent) problem," Cheng said.
Furthermore, the drip bag or paper filter is normally used only once, he added. Also, there have been no international regulations that restrict the use of wet strength agents.
"People need not panic" over what the nephrologist had said, Cheng said.
However, to dispel people's doubts, the FDA will begin to test the safety of drip bag coffee and paper filters for coffee at its laboratory in the near future. If any health risks are found, the agency will not rule out the possibility of changing the relevant regulations, the official said.
Chiang is a national celebrity known for promoting a healthy diet and toxin-free food products. He is the founder of the Dr. Chiang chain of health food shops.
Wet strength agents are mostly made of polyaminopolyamide-epichlorohydrin (PAE) resin to improve the strength of paper when soaked in water while retaining its filtering capacity.
Yen Tzung-hai (???), director of Chang Gung Memorial Hospital's Toxicology Department, said he has never heard of drip bag coffee being carcinogenic.
He had tried to analyze some PAE-added wet strength agents, and found that epichlorohydrin will produce a "very tiny quantity of 3-monochloro-1,2-propanodiol (3-MCPD), which is listed by the World Health Organization as a Group 2 carcinogenic substance.
In animal trials, the long-term exposure to 3-MCPD will increase the risk of developing cancer, Yen said, but there is no evidence for such a risk in clinical trials.
He would like to ask Dr. Chiang why he believes drip bag coffee causes cancer, Yen said, calling for the nephrologist to present evidence.
Yang Chen-chang (???), head of Taipei Veterans General Hospital's Toxicology Department, also made a similar call, and pointed out that most coffee drip bags are made of non-woven cloth, instead of paper.
"In life, it is inevitable for people to come in contact with carcinogenic substances, but this may not actually cause them to develop cancer," Yang said, explaining the variety of carcinogens and their intake quantities decide if people will get cancer or not.
For example, many different kinds of fish contain carcinogens such as dioxin and mercury in minute quantities, but they also contain substances like Omega-3 that are good for human health. "The advantages of eating fish outweigh the disadvantages," the expert said.
Source: Focus Taiwan News Channel