Only residual gossypol in cottonseed oil can cause male infertility, so don't panic
The tainted oil scandal at Datuen unexpectedly made cottonseed oil the focus of public discussion, with some media even reporting that "a man who eats one tablespoon of cottonseed oil every day will be 90% infertile within a year." Jiang Zhigang, spokesperson for the Toxicology Society, clarified that it is the gossypol in cottonseed oil that has reproductive toxicity, and EU research shows that for a 60 kg adult, each intake of 6 mg or more of gossypol carries a risk of reduced sperm count. The Food and Drug Administration under the Ministry of Health and Welfare should promptly publish the gossypol content of all products containing cottonseed oil.
Currently, no gossypol residue detected in 2 oil products
The Food and Drug Administration announced yesterday evening that no gossypol residue was detected in the cottonseed oil of Fwusow and Datuen, whether crude oil or refined cottonseed oil; as for products that also contain cottonseed oil, such as margarine, popcorn, and peanut butter, whether gossypol remains and at what levels is still pending testing.
Cottonseed oil has left the general public deeply anxious. A 2012 report by the Food Industry Research and Development Institute noted that gossypol is a natural substance found in cotton, used to defend against insects and pathogens, with the highest content in the seeds; international studies have already confirmed that excessive intake of gossypol can cause sperm death in men, inhibit sperm production, and reduce sperm count, and only ruminant animals such as cattle and sheep can directly consume cottonseed gossypol. EU research has also shown that a 60 kg man who consumes 6 mg of gossypol faces a risk of reduced sperm count, though no clear residue limit has been set.
A survey by the United States Department of Agriculture last year found that Asia is the world's main producer of cottonseed oil, with China producing more than 1.5 million metric tons annually, followed by India with 1.2 million metric tons. Between 1930 and 1940, "no-baby villages" appeared in Jiangsu Province, China, where locals were suspected of long-term consumption of incompletely refined cottonseed oil, and for a full ten years no children were born. China thus became the only country in the world to set a residue limit for gossypol, with gossypol residue in edible oil not allowed to exceed 0.02%.
Gossypol once used as a male contraceptive, banned due to irreversible effects
Yan Zonghai, a nephrologist at Linkou Chang Gung Memorial Hospital, said that China, Africa, and other countries once used gossypol as a male contraceptive, finding that a single dose of 6 mg would render sperm immobile, but follow-up tracking found that 20% of men could not recover normal sperm even after stopping use, causing irreversible harm to the body. As a result, the World Health Organization fully banned gossypol as a contraceptive in 1998, though this also led to very little long-term research, making it impossible to know the effects of long-term gossypol consumption.
Regarding products on the market that still contain cottonseed oil, Yan Zonghai believes that health authorities should find ways to screen for excessive gossypol residue, but the oil products must be controlled first; if the upstream is well managed, the probability of problems downstream becomes smaller.
Refined cottonseed oil can remove gossypol and become edible
Sun Luxi, an edible oil expert and honorary professor at the Graduate Institute of Food Science and Technology at National Taiwan University, said that the oil in cottonseeds, after initial pressing or chemical solvent extraction, is called crude cottonseed oil or crude oil, which looks relatively cloudy, has a stronger color and odor, and still contains gossypol, making it unsuitable for direct consumption; after refining, most of the gossypol can be removed, making it edible. Around World War I and before World War II, it was the main oil consumed by Americans, and Japan also often used cottonseed oil to fry tempura.
According to a 2004 dietary intake survey by the United States Environmental Protection Agency, cottonseed oil was still the third-largest edible oil in the United States, with a market share of 5%-6%; about 56% was used as salad or cooking oil, 36% for baking or frying, and 8% for margarine or other uses. The gossypol content of crude cottonseed oil is about 0.51% to 1.43%, while refined cottonseed oil in the United States has a gossypol content of about 0.00% to 0.09%.
Sun Luxi said that Chinese officials happened to visit Taiwan yesterday, and they stated that cottonseed oil is a waste product of cotton production, low in price, and the main oil used by many poor families in China; the government worried about daily intake and cumulative concerns, which is why it set a gossypol residue standard. Now that China's economy has improved, oil intake is more diverse, and refining technology has also improved, the risk of eating cottonseed oil has already decreased.
