The Anti-Cancer and Other Medicinal Value of Kelp (Kunbu)
The Chinese medicinal Kunbu is the thallus of Ecklonia kurome (family Laminariaceae) and of Eckloniaonia sp. (black Kunbu) and Undaria pinnatifida (wakame) of the Alariaceae family; it is also called haidai (kelp), haidaicai, and haibaicai. What is the relationship between medicinal Kunbu and the kelp we eat daily? Precisely speaking, the kelp we eat daily is one kind of the Kunbu used medicinally, but medicinal Kunbu includes not only kelp but also Eckloniaonia and wakame and other plants highly similar to kelp in shape, composition, and efficacy. The kelp we eat daily can be used as Kunbu. Some online articles treat Kunbu and kelp as two different plants and claim kelp cannot be used as Kunbu; this is wrong.
Kunbu, black Kunbu, and wakame are all marine products. Their main components are alginic acid and alginate salts, though their full compositions are not identical. But whether viewed from traditional Chinese medicine records or modern pharmacological research, their efficacies are much the same.
Traditional Chinese medicine holds that Kunbu is salty in flavor, cold in nature, and enters the liver, stomach, and kidney meridians. It dissipates phlegm and softens hard lumps (xiaotan ruanjian), promotes diuresis and reduces swelling. It treats goiter-like tumors (yingliu), scrofula (luoli), hernia with testicular swelling, dysphagia (yege), and beriberi edema. In TCM, yingliu generally refers to thyroid tumors (both benign and malignant); luoli refers to cutaneous sarcoidosis, tuberculous lymphadenitis, or lymphoma; yege refers to gastric or esophageal cancer or esophagitis and related diseases.
Traditional Chinese medicine uses Kunbu as an important herb for treating various cancers. It is used to dissipate phlegm and nodules, often in mutually-reinforcing combination (xianggui) with Haizao (Sargassum). Many famous TCM formulas for reducing swelling and dispersing nodules contain Kunbu—such as Haizao Yuhu Decoction, Qinggan Luhui Pills, Huoxue Sanying Decoction, Fangfeng Qianghuo Decoction, Zirong Sanjian Decoction, Sanzhong Kuijian Decoction, and Juhe Pills—classic external-surgery formulas for reducing swelling and dissipating nodules, generally in relatively large doses. When treating tumor diseases, Chinese medicine often combines Kunbu with Haizao, Xiakucao (Prunella), Sanleng (Sparganium), Ezhu (Curcuma zedoaria), Qingpi (unripe tangerine peel), and Muli (oyster shell).
Animal experiments have also confirmed that Kunbu indeed has anti-tumor effects, though the anti-cancer effects of various Kunbu differ. Hot-water extracts of several kinds of Kunbu at 100 mg/kg given intraperitoneally every other day for 5 doses all showed anti-cancer activity against subcutaneously transplanted mouse sarcoma S180; the inhibition rates for narrow-leaf Kunbu, long-leaf Kunbu, and Kunbu were 94.8%, 92.3%, and 13.6%, respectively. Using the dialysate of long-leaf Kunbu at 200 mg/kg and 100 mg/kg was also effective against syngeneic L1210 leukemia in mice, prolonging survival by 125% and 120%, respectively. In addition, kelp extract has anti-cancer activity against human lung cancer cells, and wakame extract against ARRT-cell leukemia.
Kunbu is also a radiation-protective food, offering some protection to patients undergoing radiotherapy. Thus cancer patients can eat more kelp-stewed pork ribs during radiotherapy to prevent radiation injury. Since it can serve as food, Kunbu is a non-toxic herb that may be used long-term; however, those who need to control iodine intake (such as hyperthyroidism patients and those with excessive uric acid) should be careful not to eat more high-iodine foods like Kunbu.
Kunbu also enhances immunity. The fucoidan contained in Kunbu produced in the Bohai Bay has strong immune-enhancing effects both in vivo and in vitro, and the sodium alginate in Kunbu also markedly enhances the phagocytic capacity of peritoneal macrophages in experimental animals.
Besides anti-tumor effects, Kunbu lowers blood glucose and blood lipids and has anticoagulant effects (i.e., the so-called action of activating blood and resolving stasis). Kelp roots are an effective antihypertensive: dried kelp root ground into powder, taken 2–3 g with warm water three times daily, can treat hypertension. Thus patients with the “three highs” (hyperlipidemia, hypertension, hyperglycemia) who need not restrict iodine intake may use kelp as a dietary therapy and eat it often.
Kunbu helps improve constipation. Soak 1–2 liang (about 30–60 g) of Kunbu in warm water, cook until done, add suitable ginger, scallion, garlic, and seasonings, and eat as a dish all at once, once daily; this treats constipation. Among 35 constipation patients treated this way, 8 were cured and 24 improved. If one more garlic clove is crushed into a paste and applied externally on the navel for 1–2 hours, the effect is even better.
Kunbu not only improves constipation but also has a strong diuretic action. Traditional Chinese medicine uses it to promote diuresis and reduce swelling precisely because of this diuretic effect. In treating beriberi edema (partly caused by ascites), Kunbu is often combined with Haizao, Zexie (Alisma), Sangbaipi (mulberry bark), and Fangji (Stephania).
Kunbu is also a good cough-suppressing and phlegm-resolving herb, usable for bronchitis, pulmonary tuberculosis, and chronic cough. Decoct Kunbu, Baibu (Stemona), and Zhimu (Anemarrhena) in a 1:1:2 ratio, or steep them in medicinal wine, to treat intractable cough and wheeze caused by respiratory diseases.
Made into eye drops for external use, Kunbu can also treat commotio retinae, vitreous opacity, senile cataract, and other ophthalmic diseases. It is generally thought that Kunbu contains iodine, which promotes the breakdown of pathological products and absorption of inflammatory exudates, inhibits connective-tissue proliferation, improves blood circulation, and promotes metabolism—this is why Kunbu is effective for eye diseases. But there are also reports that eye drops made from Kunbu can damage the eyes.