Crab season is here! These 4 places are not recommended for eating crabs, but many people don’t know…

There is a poem from ancient times: "The belly is round in September and pointed in October, hold the claws and drink wine while appreciating chrysanthemums." This means that female crabs are the fattest in September of the lunar calendar, and male crabs are the fattest in October , which is the most suitable time to eat crabs, drink wine and appreciate chrysanthemums.

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In autumn, crabs are a delicacy on the table and should not be missed. Many people have some questions about eating crabs, such as whether eating crabs will make people fat? Can pregnant women and people with gout eat crabs? Can you eat dead crabs? This article will answer your questions.

What are the differences between river crabs, river crabs, lake crabs and sea crabs?

There are many types of crabs, the most common ones are river crabs, river crabs, lake crabs, and sea crabs. What are the nutritional differences between these four types of crabs?

Some researchers selected lake crabs (Yangcheng Lake hairy crabs), river crabs (Jiujiang crabs), river crabs (Tianjin river crabs), and sea crabs (Tianjin sea crabs) for their research.

The results showed that the protein content of these four crabs was 13.5% to 17.7%, and the fat content was 2.2% to 2.7%. Among them, river crabs had the highest protein content; lake crabs had higher protein content and lower fat; sea crabs had lower protein content and higher phosphorus, potassium, manganese, iron, zinc and copper contents; river crabs had the highest zinc content.

Figure: Comparison of the main nutrients of 4 types of crabs

Figure: Comparison of mineral content in 4 types of crabs

Can I eat crabs to lose weight?

Crabs are so plump, so they must be high in fat, right? Actually, they are not that high . The fat content of female hairy crabs is 7.7%, while that of river crabs is only 2.6%. We usually say that chicken breast and pork tenderloin are lean, but river crabs are actually leaner, with only 1/2 and 1/3 of the fat content of chicken breast and pork tenderloin.

The higher the fat content, the tastier it is. How come crabs are so plump and delicious when their fat content is not high? That’s because the fat content of crab roe and crab paste is as high as 44.3% and 34.9% respectively.

Even so, you can still eat crabs to lose weight. The energy content of crabs is lower than that of hairtail, Spanish mackerel, grass carp, and pork tenderloin, and the energy is only about 2/3 of that of pork tenderloin.

Medium-sized female and male crabs weigh about 2 liang and 3 liang, with energy contents of 43 kcal and 65 kcal respectively, which is lower than the energy content of an apple (108 kcal).

Besides, crabs are also nutritious. Crab meat is rich in protein, calcium, potassium and other nutrients . The calcium content is higher than milk, and the protein content is similar to pork leg meat. Crab roe (crab paste) contains polyunsaturated fatty acids such as lecithin and DHA. So it is completely possible to eat crabs to lose weight.

Can pregnant women eat crabs?

It is said that pregnant women cannot eat crabs because it can cause miscarriage. In fact, how can miscarriage be so easy? Clinical miscarriage, especially miscarriage in early pregnancy, is mainly caused by poor embryo quality. Crabs are not to blame for this.

Besides, crabs do not contain any ingredients that can cause miscarriage. Instead, they contain high-quality protein and unsaturated fatty acids that are suitable for pregnant women. Moreover, crabs have a low mercury content. The US Food and Drug Administration (FDA) even classifies them as aquatic products recommended for pregnant women.

So pregnant women can eat crabs, but if you feel uncomfortable after eating crabs when you are not pregnant, for example, if you are allergic to crabs, then of course you cannot eat them.

Even if you can eat it, don't eat too much. For example, it is recommended to eat about 2 hairy crabs a day in the early pregnancy, and 3-4 a day in the second and third trimesters. At the same time, don't eat other livestock and poultry meat on the same day. In addition, you must also be careful not to eat raw or pickled crabs. You must eat cooked crabs to avoid parasite contamination and harm to the health of pregnant women and fetuses.

Can I eat crabs if I have abnormal blood lipids?

The main reason for this statement is the concern about the cholesterol in crabs.

The cholesterol content of crabs is not very high. A 3-liang male hairy crab contains about 134 mg of cholesterol, which is lower than the cholesterol content of an egg (293 mg).

The cholesterol in crabs is mainly found in crab roe, and the cholesterol in crab meat is not high. People with abnormal blood lipids can eat less crab roe. And for those who only eat crabs once in a while, there is no need to worry too much.

Can people with gout eat crabs?

The purine content of river crabs is 147 mg/100 g, which is a food with a high purine content. The "Guidelines for Primary Diagnosis and Treatment of Gout and Hyperuricemia (2019)" mentions that it is best to avoid consuming crustaceans such as crabs.

What should I do if I am greedy? I definitely don’t eat it during a gout attack.

You can try one in moderation during the remission period of gout, but you should eat less other meat, and the total amount of meat per day should not exceed 120 grams. The edible part of a 3-liang male crab is about 63 grams, and the maximum amount of other meat you can eat is 57 grams, which is roughly equivalent to 4 beef rolls for hot pot.

In addition, we ordinary people should also be careful not to drink beer with crabs. After alcohol enters the human body, it will be metabolized to produce lactic acid. Lactic acid will inhibit the secretion of uric acid by the renal tubules, reducing the kidney's ability to excrete uric acid. At the same time, eating it with high-purine crabs will increase the risk of gout.

Which parts of crabs cannot be eaten?

There are actually not many edible parts of a crab, and there are 4 parts that are best not to eat.

It includes the crab's gills (the strip-shaped part after removing the crab shell), the crab 's intestines (the black strip-shaped part hidden in the crab's tail), the crab's stomach (the gelatinous triangular part in the front half of the crab shell, below the eyes), and the crab's heart (the small hexagonal white piece).

How to eat crabs healthily?

1

Choose fresh crabs

Because crabs may produce toxic substances such as histamine after death, which may cause food poisoning, especially river crabs.

Excessive intake of histamine can cause allergic poisoning symptoms such as headache, nausea, breathing difficulties, palpitations, rashes, high blood pressure, vomiting, etc. In severe cases, it can also lead to shock and endanger life. Intake of 8 to 40 mg of histamine will cause mild poisoning; more than 100 mg can cause severe poisoning.

Studies have shown that at 20°C, the histamine content in river crabs reaches 6.3 mg/100 g and 7.4 mg/100 g respectively at 3 hours and 12 hours after death; even when refrigerated at 4°C, the histamine content reaches 4.5 mg/100 g and 9.1 mg/100 g respectively at 24 hours and 72 hours.

Therefore, it is best not to eat dead crabs. When buying crabs, choose crabs with hard and firm claws, quick-reacting crab eyes, and strong vitality.

2

It’s best not to eat drunken crab

Because there may be live parasites remaining in drunken crabs.

3

Best steamed

Crabs are rich in unsaturated fatty acids, and steaming can reduce the loss of unsaturated fatty acids such as DHA. If you think steamed crabs have no taste, you can dip them in ginger vinegar to remove the fishy smell and enhance the flavor.

4

Control the amount you eat

The Chinese Dietary Guidelines recommend that adults eat 300-500 grams of aquatic products per week, which means an average of 40-75 grams of aquatic products per day, about one crab. If you feel that eating one crab is not enough, a healthy adult can eat two or three, but it is best not to eat other livestock and poultry meat on that day.

References

[1] Li Shiyu, Zuo Xiaoxia, Wang Jing, et al. Analysis of nutritional components of crabs from different waters[J]. Acta Nutrienta Sinica, 2022, 44(03): 311-312. DOI: 10.13325/j.cnki.acta.nutr.sin.2022.03.011.

[2] Yang Yuexin. Chinese Food Composition Table 6th Edition Volume 2[M]. Peking University Medical Press, 2019

[3] Cao Zhenjie, Fu Chunpeng, Zhou Siquan, et al. Comparative analysis of the nutritional components of the “crab roe” and “crab paste” of Chinese mitten crab [J]. Fisheries Science, 2017, 36(02): 178-182. DOI: 10.16378/j.cnki.1003-1111.2017.02.010.

[4]Xu Zitong, Sun Wenkai, Shang Qingfa. A case of death due to histamine poisoning caused by eating river crabs[J]. Guangdong Public Security Science and Technology, 2021, 29(1): 64-65.

[5] Wang Yahui, Wang Xichang, Wang Shuai, et al. Evaluation indexes of freshness and corruption degree of aquatic products[J]. Food and Fermentation Industries, 2015, 41(10): 240-246.

[6] Chinese Nutrition Society. Dietary Guidelines for Chinese Residents[M]. People's Medical Publishing House. 2022

Planning and production

Source: Nutritionist Gu Chuanling (id: guchuanlingyys)

Author: Gu Chuanling, Deputy Secretary General of Capital Health Nutrition and Gourmet Society, Registered Nutritionist

Editor: Yinuo

Proofread by Xu Lai and Lin Lin