This common fruit in the north is loved by many people. Can it also treat diabetes? The answer is different from what you think!

Rumor: "Ginkgo nuts are very nutritious and can treat diabetes"

There is a rumor among the people that eating ginkgo nuts is very nourishing, can prolong life, and can also treat diabetes. Therefore, in the north, at this time of year, you can see many people picking gingko nuts under the ginkgo trees...

Rumor analysis: Actually, this is not the case.

There is no evidence that eating ginkgo nuts can cure diabetes. If you have blood sugar problems, don't blindly eat ginkgo nuts for "treatment". You should still follow your doctor's advice. As for prolonging life, this cannot be achieved by eating a certain food.

This season is the most beautiful time for ginkgo trees. People can't help but stop and take out their phones to take some memorable photos. The fallen leaves can also be picked up and used as bookmarks. In addition to appreciating the deliciousness of ginkgo leaves, its seeds often appear on the table. Some people say it is nutritious, while others say it is poisonous. Can it be eaten?

The nutritional value of ginkgo is not magical

Ginkgo is the oldest plant among the existing seed plants, with a history of hundreds of millions of years on Earth. From the late Cretaceous period of the Mesozoic Era to the Quaternary Ice Age of the Cenozoic Era, the climate on Earth changed dramatically, and the surviving ginkgo became one of the oldest "living fossils" among seed plants. Ginkgo trees have no fruits, only seeds, which are called ginkgo nuts, also called duck feet, Buddha finger oranges, and spiritual eyes. People will classify it as a nut food. The mature ginkgo nuts are orange-yellow or light yellow, and are nearly spherical or elliptical in shape.

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There are rumors among the people that eating ginkgo nuts is very nourishing, can prolong life, and can also treat diabetes. In fact, there is no evidence that eating ginkgo nuts can treat diabetes. If you have blood sugar problems, don't blindly eat ginkgo nuts for "treatment". You should still follow the doctor's advice. As for prolonging life, this cannot be achieved by eating a certain food.

The nutritional value of ginkgo is not amazing, and it cannot be considered a tonic. Its nutritional components are the same as the common nuts we usually eat, including starch, protein, fat, dietary fiber, unsaturated fatty acids, vitamins and minerals, and also some antioxidants. The carbohydrate content of ginkgo is as high as 72.6 g/100 g, which is much higher than the walnuts, almonds, pine nuts, hazelnuts and other nuts we usually eat, 3 to 4 times higher than them, and about the same as chestnuts (chestnuts: 78.4 g/100 g); the protein content is about 13 g/100 g, which is not high among nuts. The protein content of hazelnuts we usually eat is 20 g/100 g; the dietary fiber content is 2.19 g/100 g (including the outer seed coat), which is only 1/4 of that of hazelnuts; the potassium content is not as good as that of hazelnuts, at 998 mg/g; it also contains some antioxidants such as flavonoids, polyphenols and terpenes. In terms of other nutrients, there is nothing special worth mentioning except that the content of folic acid and B vitamins is relatively richer than other nuts.

*Representative data from the USDA Nutrient Database [3]; dietary fiber content from reference [2]

Ginkgo nuts cannot be eaten casually

Although ginkgo nuts are also a type of nut, they cannot be eaten casually, and you should be careful of poisoning. From ancient times to the present, there have been records of poisoning caused by eating ginkgo nuts.

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The ancient text "Sanyuan Yanshou Shu" wrote: "Once upon a time, there were hungry people who ate ginkgo instead of rice until they were full. The next day, they all died."

In 2012, a 45-year-old woman in Beijing was hospitalized for poisoning symptoms after eating about 10 ginkgo nuts. She was rescued and recovered. In September 2020, Ms. Zhou in Chengdu, Sichuan, was admitted to the ICU ward of the hospital for treatment after eating one and a half kilograms of ginkgo nuts. From January 2011 to December 2015, a hospital in Jiangsu Province admitted 51 children with acute ginkgo poisoning. Since 2006, about 250 people in my country have been poisoned by eating ginkgo nuts. It can be seen that ginkgo poisoning should not be underestimated. The fleshy outer seed coat of ginkgo contains toxic ingredients such as ginkgo biloba, ginkgolic acid, hydrogenated ginkgolic acid, hydrogenated ginkgolic acid, and ginkgol. The seed kernel contains trace amounts of cyanogenic glycosides, which are also toxic. In addition, 4'-methoxypyridoxine in ginkgo is considered to be the main toxin. Its chemical structure is similar to that of vitamin B6, and it has an antagonistic effect on vitamin B6, which can cause the body to lack vitamin B6 and show symptoms of poisoning. It is easy to be poisoned by eating ginkgo raw. The incubation period is generally 1 to 12 hours, and can be up to 16 hours. After poisoning, the main manifestations are symptoms of the central nervous system and gastrointestinal tract, and occasionally peripheral nerve dysfunction. It can be manifested as nausea, vomiting, convulsions, cyanosis of the lips, foaming at the mouth, limb rigidity, rapid breathing, abdominal pain, diarrhea, etc., and even coma or difficulty breathing, and severe cases can also lead to death.

If you want to eat ginkgo nuts, this is the way

Ginkgo toxins are mainly found in the outer seed coat and germ. These toxins are soluble in water and can be partially decomposed by heat to reduce toxicity. To avoid poisoning, the seed coat and germ should be removed before eating ginkgo, and then boiled in water.

Figure: Reference [6]

If cooked and then microwaved, fried, or baked, the ginkgo toxin in the ginkgo nuts can be further pyrolyzed, but the nutritional value and sensory properties of the ginkgo nuts will be destroyed at the same time. Although cooked ginkgo nuts can be eaten, they should not be consumed in excess. For safety reasons, it is recommended not to consume more than 10 nuts at a time. Children and infants should be especially careful. There are reports that 5 to 10 nuts can cause ginkgo poisoning in young children. In addition, the storage method of ginkgo nuts will also affect the toxin content. It is recommended to store them in a frozen state at -20°C with the shell. In other words, raw ginkgo nuts are very toxic, so don't eat them! Cooking can reduce the toxicity of ginkgo nuts but cannot eliminate it. For safety reasons, it is recommended that adults consume no more than 10 nuts a day, and children should not consume more than 5 nuts a day. Infants and young children are prohibited from eating them.

Reminder: Don’t pick up ginkgo seeds on the roadside

After cooking, the ginkgo nuts have a soft and sweet taste, and many people like to eat them. So much so that every late autumn, many people go to the ginkgo tree to pick up the fallen ginkgo seeds, which is not recommended. First of all, the peel of fresh ginkgo nuts contains a large amount of ginkgolic acid, which is highly allergenic. Direct contact with the hands can cause skin allergies, symptoms such as burning, itching, erythema, swelling, and severe anaphylactic shock. Secondly, the ginkgo trees on the roadside are landscape trees, which are not only polluted by the surrounding environment, but also may be sprayed with pesticides. Besides, the ginkgo nuts that fall off the tree smell very bad, and most people can't accept it. This is because the outer seed coat of the ginkgo contains butyric acid, caproic acid and other substances, which have a sour and smelly smell. In summary: There are many ways to cook ginkgo nuts. You can eat them directly after cooking, cook porridge, and cook dishes, such as braised pork with ginkgo nuts, chicken soup with ginkgo nuts, white fungus and ginkgo soup, etc. You can also make salt-baked ginkgo nuts. But be careful to avoid poisoning. Do not eat it raw or in excess!

Looking in the mirror of rumors

Many of the diet rumors we are familiar with exaggerate the effects of certain foods. In fact, no single food can cure diseases. Therefore, when you see such rumors, you should keep your eyes open and don't try them easily. If you feel unwell, go to the hospital immediately.

References

[1] Yang Yuexin. Chinese Food Composition Table 6th Edition Volume 1[M]. Peking University Medical Press, 2018

[2] Wu Ping, Yao Fang, Qi Xingpu, Liu Ping, Wang Haibo, Xu Jiaman, Zheng Haisong. Main components and functional activities of Ginkgo biloba resources[J]. Food Industry Science and Technology, 2022, 43(9): 447-455

[3]https://fdc.nal.usda.gov/fdc-app.html#/food-details/170175/nutrients

[4] Zhu Chuanming. Experience in treating 80 cases of acute ginkgo poisoning [C]//Emergency Medicine Branch of Zhejiang Medical Association, Emergency Medicine Branch of Jiangsu Medical Association. Proceedings of the 2018 Zhejiang and Jiangsu Provincial Emergency Medicine Annual Conference. Changxing County People's Hospital;, 2018:2.DOI:10.26914/c.cnkihy.2018.030920.

[5]https://www.cfs.gov.hk/tc_chi/multimedia/multimedia_pub/multimedia_pub_fsf_204_02.html

[6] Zou Minmin. Study on tissue distribution, storage and processing changes of ginkgo biloba toxicity and its enzymatic removal[D]. Nanjing Forestry University, 2021. DOI: 10.27242/d.cnki.gnjlu.2021.000060.

[7] Zhao Juan, Wei Xianhe. Clinical analysis of 51 cases of acute ginkgo poisoning[J]. Journal of Qiqihar Medical College, 2016, 37(20): 2525-2527

Author: Xue Qingxin, registered nutritionist

Review丨Zhang Yu, researcher/PhD, Chinese Center for Disease Control and Prevention, national health science expert