Why eating roadside ginkgo nuts can be dangerous

Ginkgo nuts that fall abundantly along streets in autumn may look harmless, but eating them without proper preparation can be dangerous, experts warn.

Food and nutrition researchers said Thursday that ginkgo nuts, despite their nutty flavor, contain toxic substances that can be harmful when consumed in excess. Raw ginkgo nuts contain higher concentrations of toxins and must be roasted or cooked before eating. Adults should limit intake to 10 kernels per day, and children should eat no more than three.

The main toxic compounds in ginkgo nuts are cyanogenic glycosides and methylpyridoxine. Cyanogenic glycosides convert into hydrogen cyanide in the body, causing dizziness, vomiting, diarrhea and other symptoms of acute poisoning. Severe cases can lead to loss of consciousness, impaired oxygen supply and cyanosis.

Methylpyridoxine interferes with the function of vitamin B6, which is essential for maintaining the nervous system. It disrupts the production of the neurotransmitter GABA in the brain, potentially causing seizures and breathing difficulties.

Large quantities can result in loss of consciousness, convulsions and even death. The compound remains stable under heat, meaning toxins are not fully removed even when cooked.

A case reported by Soonchunhyang University Cheonan Hospital in 2011 described a 58-year-old man who collapsed after consuming a large number of ginkgo nuts. The man suddenly vomited and lost consciousness at dawn, and was taken to the emergency room. His condition did not improve after arrival, and he vomited brown material several times before experiencing full-body seizures.

Doctors found large amounts of ginkgo nuts in his vomit. He had been eating four to five roasted nuts with his meals for two days after picking them up from the street, but the night before his collapse he had consumed about 200 nuts.

Doctors diagnosed prolonged seizures caused by ginkgo nut poisoning and administered 50 milligrams of pyridoxine, a form of vitamin B6. The man gradually recovered, regained consciousness after four days and was discharged on the 10th day following normalized EEG results.

Experts said that ginkgo nuts should always be cooked and that intake must be strictly limited. “Plant seeds contain nutrients such as fats, proteins, carbohydrates, vitamins and minerals, but some seeds also produce natural toxins like cyanogenic glycosides for self-protection,” one expert said. “Following proper consumption guidelines is essential.”

This article from the Hankook Ilbo, the sister publication of The Korea Times, is translated by generative AI and edited by The Korea Times.