encyclopedia

Dulse

Scientific Names:    

Rhodymenia palmata (Linnaeus) Greville (syn. Palmaria palmata (Linnaeus) Stackhouse) [Fam. Rhodophyceae]

Forms:    

Dried and powdered dulse; aqueous extract of dulse

Traditional Usage:    

– Antioxidant
– Cellular Regeneration
– Chewing Tobacco
– Constipation
– Cleansing
– Detoxifying
– Expelling Placenta (externally)
– Goiter
– Headache (externally)
– Health Tonic
– Laxative
– Iodine Deficiency
– Mineral Deficiencies
– Poultice/Plaster
– Scurvy
– Skin Problems (externally)
– Vermifuge
– Vitamin Deficiencies
– Weight loss
– Worms
– Wound Healing (externally)

Overview:    

The seaweed known as dulse, Rhodymenia palmata (Linnaeus) Greville (syn. Palmaria palmata (Linnaeus) Stackhouse) and R. edulis [Fam. Rhodophyceae], otherwise known as Neptune’s girdle, is a rosy-bladed red algae that is widely distributed in the Atlantic & Mediterranean Oceans. Dulse has purple-red short-stemmed fan-shaped fronds that grow in tidal areas on rocks, shells and larger algae. Dulse is rich in vitamins and minerals including iodine and can be eaten raw, roasted, boiled, fried or dried as a relish. The custom of eating dulse, an acquired taste, dates back to at least 600 A.D. in northern Europe. Dulse used as a medicine is said to have a tonic effect and was traditionally used to treat scurvy and constipation. Dried, powdered dulse was also traditionally used to treat worms. Externally, a plaster of the fresh blades is used to treat skin diseases, headaches, and to help expel placenta. Dulse was also traditionally dried and rolled for chewing tobacco. Dulse is an excellent source of iodine, a major component of the human hormones thyroxine and triiodothyronine that affect weight gain and cellular metabolic rates. One to two milligrams of iodine weekly are required to prevent goiter. Dulse has also been employed to help prevent fibroid tumors of the breasts, the uterus or the ovaries and in cases of swollen lumps or enlargements of the intestinal area also known as lymphatic areas. In simple goiter the basal metabolic rate is somewhat lowered, and in toxic goiter it is elevated. Based on epidemiological studies, thyroid disease is practically unknown in people who regularly eat edible seaweed. Natural, organically-bond iodine extracts from dulse are available commercially for the treatment and prevention of thyroid disease. Based on human clinical trials, 4mg of molecular iodine daily completely resolves cyclical breast lumps and cysts, usually within only two months.

Active Ingredients:    

Dulse contains: Approximately 18.2% ash. Minerals include: aluminum (0.06%); arsenic (0.003%); ascorbic acid (0.012%); calcium (0.6%); alpha-carotene; beta-carotene; chromium (0.002%); cobalt (0.015%); alpha-cryptoxanthin; beta-cryptoxanthin; iodine; iron (0.08%); lead (0.0003%); lutein; magnesium; manganese; mercury (0.002%); niacin (0.003%); phosphorus (0.4%); potassium (2.3%); protein (13.3%); riboflavin (0.0001%); selenium (0.003%); silicon (0.004%); sodium (9.9%); thiamin (0.0002%); tin (0.003%); zeaxanthin; and zinc (0.004%). Dulse also contains desmosterol (5,24-Cholestadien-3beta-ol).

Suggested Amount:    

Dulse is most often eaten as a dry food snack or used as a spice or more liberally as a sea vegetable in soups and broths. For medicinal purposes, 5-10 grams of dulse can safely be used daily (1-2 teaspoons prepared as an infusion). Dulse is most often used medicinally as an iodine extract.  Standardized iodine extracts of dulse or other seaweeds should be taken according to the dosage of iodine required and only under the supervision of a qualified medical practitioner or physician. For use externally as a plaster, macerate dulse fronds with a small amount of water and apply wet for tightening to occur while drying.

Drug Interactions:    

At normal dosages: None known. In large dosages: The iodine content in dulse may cause hyper- or hypothyroidism if taken in excessive amounts, and may interfere with existing treatment for abnormal thyroid function. Seek the advice of a qualified medical practitioner if you wish to use dulse as a food or medicine in these cases.

Contraindications:    

At normal dosages: None known. In large dosages: The iodine content in dulse may cause hyper- or hypothyroidism if taken in excessive amounts, and may interfere with existing treatment for abnormal thyroid function. Seek the advice of a qualified medical practitioner if you wish to use dulse as a food or medicine in these cases.

Side Effects:    

At normal dosages: None known. In large dosages: Hyperthyroidism has been associated with the excessive ingestion of seaweed and is attributable to the iodine content in the plants. Typical symptoms of hyperthyroidism include: weight loss, sweating, fatigue, heart palpitations and frequent soft stools. The iodine content in seaweed has also been associated with acne eruptions and may aggravate pre-existing acne. Dulse is most often used medicinally for preventing or treating goiter, a disease of the thyroid gland characterized by an enlargement of the gland, visible externally as a swelling on the front of the neck. According to Dr. A. B. Howard in the book, Herbal Extracts (1990), the thyroid plays a key role in the rate at which calories are burned, controls calcium levels in blood stream, hair growth, skin and nails and ovarian health. Symptoms of an unhealthy thyroid include: swelling of thyroid, fearfulness, cold hands and/or cold feet, hands that tremble when the arms are extended with the fingers spread apart, weight and temper problems. Dulse may be used to prevent or treat these conditions, but in excessive amounts can also cause thyroid problems. Seek the advice of a qualified medical practitioner if you wish to use dulse as a food or medicine but have a pre-existing thyroid condition. Seaweed used as a food and/or for a medicinal product should not exceed arsenic levels above 3.0 ppm and lead levels above 10.0 ppm based on the internationally recognized Food Chemicals Codex. Prolonged ingestion of seaweed in excessive quantities may also reduce gastrointestinal iron absorption and affect absorption of sodium and potassium and cause diarrhea.

References:     

Duke JA. 1992. Handbook of Phytochemical Constituents of GRAS Herbs and Other Economic Plants. CRC Press, Boca Raton, FL, pp. 519.

Goh, E.H.  Regulation of hepatic cholesterogenesis by exogenous cholesterol investigated with 3H-desmosterol tracer.  The Pharmacological Effect of Lipid 2:303-313, 1985.

Guiry, M.D. (1974). A preliminary consideration of the taxonomic position of Palmaria palmata (Linnaeus) Stackhouse = Rhodymenia palmata (Linnaeus) Greville. J. mar. biol. Ass. U.K., 54: 509-528.

Idler DR, Atkinson B. 1976. Seasonal variation in the desmosterol content of dulse (Rhodymenia palmata) from Newfoundland waters. Comp Biochem Physiol B. 1976; 53(4): 517-9.

Wernert, S., Berenson, RJ, Dwyer, J, and S. French (Eds.) 1982. Reader’s Digest North American Wildlife: An Illustrated Guide to 2000 Plants and Animals. Publ. by Reader’s Digest, Pleasantville, N.Y., U.S.A. Pp. 529.