As a kind of popular edible seaweed in Japanese cooking, Kombu or Kun Bu used in cuisine has a long history in East Asia. It was first recorded in Erya (Erh-ya) about 2,800 years ago. There it was named as Guan Bu. Here “Kun” means “big” and it was named so because it looks like a large textile cloth woven by ancients. Kombu actually is a type of kelp that grows in tropical waters. Since t is rich in calcium, vitamins, minerals, dietary fiber, and other nutrition that are lacking in most modern people, it is also known as one of the best sea vegetables. As everyone knows, iodine is an essential element of the human body and the deficiency of it is very likely to lead people to suffer from goiter. But eating kelp can effectively prevent and cure this disease since it is high in this element. More than that, it is able to prevent atherosclerosis, lower cholesterol, and reduce fat accumulation too.
What is Kombu?
Medicinally Kombu refers to a few different algae types, among which Laminaria japonica Aresch. is the major one. But sometimes it also means Ecklonia kurome Okam. or wakame [Undaria pinnatifida (Harv.) Sur.] And it has a number of other names, such as Brown Algae, laminaria digitata, Saccharina japonica, Hai Dai, dashima, Thallus Algae, Thallus Laminariae seu Eckloniae, Kelp Thallus, Thallus Eckloniae, Brown Seaweed, tangle, Laminaire, konbu, and so on. In China it is mainly produced in Shandong, Liaoning, Zhejiang and other places. Summer and autumn are the best seasons for harvesting kelp. Next it needs to remove impurities, rinse, shred, and dry them in the sun.
Laminaria japonica is perennial large brown algae. It is in the shape of a band when matured and can reach up to 6 meters. It has a large root like holdfast, which is fibrous and composed of a few forked rhizoids. And at the end of the rhizoid there is sucking disc. Above there is a short cylindrical handle, which is 5 to 15cm long. The thallus is elongated ovate when young and stretches into flat strip that measures 2 to 6 meters long and 20 to 50cm wide. The thallus is leathery, thicker in the center, thin on both sides, and with thin wavy folds. During reproductive period there is sporangium on both sides of the thallus. It grows in the cold ocean, usually attached on the rocks 2 to 3 meters below the tide line in seaside. Or it is cultivated on ropes and bamboo.
Main chemical constituents of Japanese kombu are polysaccharides, LPS (lipopolysaccharide), three water-soluble arsenic compounds, amino acids, volatile oil, carotene, vitamin B1, B2, C, P , sulfur, potassium, magnesium, calcium, phosphorus, iron, manganese, molybdenum, iodine, aluminum, phosphate radical, carbonate, sulfate radical, etc.
Kombu health benefits
This edible seaweed a vegetable with very high nutritional value. Each 100 dried kombu contains 8.2g crude protein, 0.1g fat, 57g carbohydrate, 9.8g fiber, 12.9g inorganic salt, 2.25g calcium, 0.15g iron, 0.57mg carotene, 0.69mg thiamine (vitamin B1), 0.36mg riboflavin (vitamin B2), 16mg niacin, and 262 calories. Compared to spinach and oilseed rape, its crude protein, sugar, calcium, and iron levels are several times or dozens times higher. In addition, cultivated kombu generally contains iodine at 3 to 5%, or sometimes as many as 7 to 10%. And the iodine and alginic acid distilled are widely used in pharmaceutical, food and chemical industry. Eating kelp has tons of health benefits.
1. It contains large amounts of mannitol, which induces diuresis to reduce edema and thus prevent and cure renal failure;
2. The synergistic effect of mannitol, iodine, potassium, and niacin can help atherosclerosis, hypertension, chronic bronchitis, chronic hepatitis, anemia, edema and other diseases;
3. It is rich in calcium, iodine and a variety of minerals, which can regulate endocrine and calcium concentration, and effectively control the loss of calcium;
4. Pectin within kelp can promote bowel movements and prevent constipation. At the same time because it significantly reduces cholesterol, it has become a popular supplement for patients with cardiovascular disease;
5. Regular consumption of kelp can increase iodine intake and the absorption of calcium, which is the major reason why it is believed with anti-cancer effect by some people;
6. Shi Liao Ben Cao (The Materia Medica for Successful Dietary Therapy), published in Tang Dynasty, ever said that it could descend qi and make people thin down. It can help weight loss, especially on hypothyroidism-induced obesity, for a few reasons. To start with, modern studies have confirmed that kombu contains laminarin, which is a polysaccharide. Next, its low concentration of sulfuric acid compound works like heparin to eliminate lipids. In addition, it also contains a variety of minerals and trace elements that can reduce the deposition of animal fat on heart, blood vessels, and intestinal wall. Finally, it has a large number of alginate, which does not generate calorie but give an obviously sense of satiety because it can delay gastric emptying;
7. Various nutrients contained are beneficial to hair. That’s to say, eating kelp can prevent hair loss and keep your hair lustrous and strong;
8. It is a tasted food and flavor enhancer. There are tons of well-known kombu recipes out there, such as kombu dashi, kombu tea (Kombucha), kombu noodles, kombu beans, kombu and katsuobushi dashi, kombu cured fish, miso soup, and more.
Selected herbal remedies on kelp
In the eyes of traditional Chinese medicine, it is salty in flavor and cold and non-toxic in medicinal properties. It involves with meridians of liver, stomach, kidney, and spleen. Vital functions are dissolving phlegm, softening hard mass, and inducing diuresis for removing edema. Kombu uses and indications include scrofula, goiter and tumor, dysphagia, hernia, beriberi, and edema. Recommended dosage is from 5 to 15 grams in decoction, pills, or powder.
1. Kun Bu Wan from Guang Ji Fang (Widely-Used Formulas). This formula is basically used for qi goiter, fullness and tightness in chest and diaphragm, and accrescent throat and neck. Other herbal ingredients are Tong Cao (Rice Paper Pith), Yang Ye (goat thyroid), Hai Ge (sea clam), and gulfweed.
2. Kun Bu Fang from Sheng Ji Zhong Lu (The Complete Record of Holy Benevolence). This prescription combines kombu with old cow’s saliva and Bai He (Lily Bulb) to treat dysphagia syndrome.
3. Kun Bu Huo Fa from Widely-Used Formulas. This recipe is formally made for abdominal distension due to qi stagnation. The other herb is Cong Bai (Spring Onion).
Kombu side effects and contraindications
Because Kombu is of cold nature, it shouldn’t be used by those with deficiency-cold in spleen-stomach accompanied with accumulated dampness. According to the animal experiments, polysaccharide extracted from kelp (1000mg/kg) was given to mice but no toxicity was found; and the intraperitoneal injection in the mice showed that the median lethal dose was 158.5 ± 67.0mg/kg. In addition, the intravenous infusion of polysaccharide sulfate showed no adverse reactions in most cases. But a few of them ( 23 out of 758 cases) were reported with sore arms and legs, joint swelling, tongue numbness, or reusable deafness in individuals. But the situation is rather mild and the patients will self heal quickly after stopping the medication. And usually no side effects will occur if the dose and infusion rate are under strict control. Be that as it may, due to kelp may lead to jeopardously high iodine and potassium levels it shouldn’t be used in the following cases – hyperthyroidism, kidney problems, breast-feeding and pregnancy.