Ascophyllum nodosum

Herbs gallery - Kelp

Common names

  • Egg Wrack
  • Kelp
  • Knotted Kelp
  • Knotted Wrack
  • Norwegian Kelp

Ascophyllum nodosum, more commonly known as kelp, is actually brown-hued seaweed that is related to the Fucus family. This oceanic weed takes the shape of a solitary bladder that at its center has elongated fronds akin to straps. These fronds suspend in a descending manner, lightly wrapping the inter-tidal rocks. Some fronds of kelp also grow from either basal holdfast and generally this seaweed redevelops fresh fronds from its foot when any of its relatively larger fronds is harmed. This is done to make the stands continue to be persistent on the shore. The oceanic weed reproduces during spring in striking yellow hued receptacles. The receptacles grow in reaction to short days during autumn, become mature in winter and are known to be the most productive during spring. The eggs as well as sperms are discharged into the sea water. Soon the eggs discharge a sperm attractant called Finnavarene, which is a low weight molecule, and derives its name from the Irish village Finavarra, which means 'wood beside the sea'.

This species of seaweed possesses elongated fronds having big air bladders in the shape of eggs and they are placed in sequence at regular spaces inside the fronds and are not like stalks. Each frond can grow up to a length of about two meters and it is bound by a holdfast to the rocks as well as boulders. These fronds have an olive-brown hue and are slightly compacted, but do not have a mid-rib.

The seaweed Ascophyllum nodosum is a member of the Fucaceae family and it is found growing extensively in the northern part of the shores of the Atlantic Ocean, ranging from America to Europe. In addition to being used for preparing therapeutic supplements, this seaweed is extensively used in the form of foods for humans as well as animals. Moreover, Ascophyllum nodosum is also employed to make agricultural products.

Parts used



It is important to note that people who dislike or keep away from sea foods are susceptible to developing deficiency of iodine. In turn, deficiency of iodine may result in hypothyroidism (a condition wherein the thyroid glands function poorly), goiter and other health conditions. Findings of researches undertaken by epidemiologists have hinted that people who consume the usual Asian food preparations usually have lesser chances of developing cancers dependent on hormone malfunctioning compared to people who are habituated to Western diets. In fact, such differences in diets have primarily been attributed to more ingestion of soy and soy products by the Asians. However, scientific studies undertaken by researchers on rats and cells, from UC Berkeley hint that dietary kelp has anti-estrogenic actions and this may possibly help in lessening the rates of different forms of cancer.

Scientists in Japan also assert that studies undertaken with kelp have shown to be effectual in extending the life span in mice, despite being fed with foods that contained carcinogenic substances. It is worth mentioning here that Ascophyllum nodosum possesses phenolic elements and as a result it has antioxidant, α-amylase and α-glucosidase inhibiting activities. Hence, it is natural that kelp (Ascophyllum nodosum) is expected to provide us with various health benefits.

Consumption of kelp (Ascophyllum nodosum) is likely to be beneficial for people who have been struggling with the health condition called fibrous breast tissue and even pain and swelling inside their mouth owing to chemotherapy as well as ulcers in the foot (people suffering from diabetes). As a result, Ascophyllum nodosum or kelp is used in the form of supplements and it is available commercially as tablets, capsules as well as powders.

During one scientific research, scientists extracted an unfractionated fucoidan from the brown alga called Ascophyllum nodosum. It was found that the fucoidan from kelp lessened the viability of cells and encouraged apoptosis of the cells of HCT116 colon carcinoma. In fact, HCT116 cells' fucoidan treatment encouraged the activation of caspases-3 and caspases-9 as well as the splitting of PARP, which resulted in apoptotic morphological alterations and, at the same time, changed the permeability of the mitochondrial membrane. In this manner, kelp may possibly be beneficial for people who are susceptible to certain forms of cancer. However, there is a need for further studies to establish the claim regarding this particular health benefit of kelp.

The Ascophyllum nodosum species (kelp) is likely to offer a number of health benefits against specific infections. However, the studies in this regard are in a preliminary stage and further researches are required to establish this particular claim.

A study involving 23 people - subjects who ingested a form of commercially available combination of brown seaweed (a blend of Ascophyllum nodosum plus Fucus vesiculosus), 500 mg every time at least 30 minutes before consuming bread containing 50 mg of carbohydrates. It was found that compared to the subjects who were given a placebo, people consuming the seaweed experienced about 12.1 per cent decrease in their insulin incremental region below the curve as well as a 7.9 per cent rise in the Cederholm index of their insulin sensitivity. Ingesting a single dose of 500 mg brown seaweed (the blend of two oceanic plants), however, did not have any noticeable influence on their response of glucose.

The responses of glucose as well as insulin were the same in the case of men as well as women. And importantly, consuming the combination of Ascophyllum nodosum and Fucus vesiculosus (brown seaweed) capsules did not have any relation whatsoever with the negative side effects. The data obtained from the study hint at the fact that consumption of brown seaweed may possibly change the insulin homeostasis in reaction to ingestion of carbohydrate. In this way, kelp may possibly be beneficial for people who are susceptible to diabetes. Nevertheless, experts are of the view that further researches are required to ascertain the beneficial effects of kelp in this regard.

Ascophyllum nodosum or kelp may possibly also be beneficial for people who are struggling to lose some additional body weight. In addition, kelp may also be useful for people who have elevated levels of triglycerides. It has already been established that consuming seaweed isolates, for instance, alginate, is effective in lessening the intake of energy and, at the same time, to adjust choleserolaemic as well as glycaemic responses.

Ascophyllum nodosum is mainly harvested for its use in fertilizers, alginates (a salt or ether of alginic acid) as well as for manufacturing seaweed foods for consumption by humans as well as animals. Since long this seaweed species has been utilized in the form of an organic as well as a typical fertilizer for growing various crops, as it not only contains macronutrients like calcium, phosphorous, nitrogen, sulphur, magnesium and potassium, but also encloses micronutrients, such as copper, manganese, zinc, iron and others. In addition, Ascophyllum nodosum also acts as a host for auxin-like gibberellins, cytokinins, mannitol, betaines, polysaccharides, organic acids, amino acids as well as proteins - all substances that are extremely beneficial and used extensively in agriculture. It is worth mentioning here that majority of the world's alginate supplies come from countries like Ireland, Norway and Scotland.

Often, the species Ascophyllum nodosum is used in the form of packaging material for lobster and baitworm shipments from New England to a number of domestic as well as global locations. At times, this Ascophyllum seaweed species has introduced itself into California. In addition, many species of Ascophyllum, including Littorina saxatilis and Carcinus maenas, are found in shipments of baitworm. And, in this way, it may possibly have been introduced to various regions of the San Francisco bay.

Culinary uses

Kelp is also used for culinary purposes and traditionally it has been used in the form of a vital food, particularly when there is a dearth of foodstuff.

You may boil this oceanic vegetable to prepare a soup stock and extract and eat the seaweed from it along with salads or other dishes. In addition, you may also dry up seaweeds and pulverize them into a powder and use it in your cooking.

It may be noted here that alginic acid that is used in different food preparations is actually prepared with extracts obtained from Ascophyllum Nodosum.

Habitat and cultivation

Ascophyllum Nodosum is found growing in a variety of habitats along the coasts, ranging from protected estuaries to more or less exposed coasts. Often, it also takes over the inter-tidal zone (even though it is known that sub-tidal populations are present in water that is very clear).

On the other hand, this species is seldom found on shores that are exposed and in case they are ever found in exposed shores, generally the fronds are small and severely scratched. It may be noted that the growth of this variety of seaweed is extremely slow - it just grows by 0.5 per cent in a day, but it may live long - as many as 10 to 15 years! Characteristically, the distribution of Ascophyllum Nodosum may partly cover other species like Fucus serratus and Fucus vesiculosus. In fact, the distribution of this seaweed is restricted by a number of things, such as salinity of the water, temperature, exposure to waves, overall stress and desiccation. On average, this seaweed may roughly take as many as five years before it becomes capable of reproduction.

In a number of areas, kelp is also found growing in semi-sheltered shores, inhabiting the littoral zone, which becomes exposed where there is low tide, but remain inundated when at times of high tide.


Similar to several seaweeds, kelp (Ascophyllum Nodosum) is packed with lots of nutriments that aid in sustaining optimal health. Kelp contains elevated concentrations of iodine, iron, potassium, calcium and manganese and many other nutrients. It also contains over 11 different vitamins, as many as 20 amino acids and about 60 essential minerals.

Usual dosage

Ever since iodized salt was introduced into the market, the requirements for other iodine sources like kelp became redundant for majority of the people. Nevertheless, if one wants, he/ she can consume kelp in the form of a source of minerals other than iodine. According to a report from Great Britain, on average, a supplement based on kelp contains about 1,000 mcg iodine, whereas the daily iodine RDA for healthy adults in the US is just 150 mcg. Hence, it has been recommended that ingestion of 2,000 mcg of iodine daily should be considered as too much or possibly detrimental for the health of people.

Side effects and cautions

Ingestion of kelp in excess of 2,000 mcg in a day may possibly result in the obstruction of the usual functioning of the thyroid gland and may also cause other different detrimental side effects.

In fact, there are many case reports that show that taking kelp in excessive dosage supplies surplus iodine to the body and this too may obstruct the usual functioning of the thyroid glands. Therefore, people suffering from thyroid problems, dermatitis herpetiformis or any different type of thyroid problems ought to consult their physician prior to taking any supplement that encloses kelp.

Seaweed mineral bath

by Louise Gaudet - www.bckelp.com

  • Bladderwrack (Fucus spp.) about 40 grams
  • Muslin pouch or cotton scarf

Place Bladderwrack Flakes in pouch or scarf, tie well closed with elastic or string (loose seaweed flakes may clog drain).
Throw pouch in hot bath water. Jump in .Gently squeeze pouch and rub algin (rich seaweed gel) all over body and face. Breath in fresh ocean breeze (not fishy at all). Relax!

Bladderwrack contains all the minerals that your body needs. It is very nourishing to the skin and soothes muscles and joints.
I am a professional Wildcrafter of seaweed, and we sell high quality kelp (Nereocysiis leutkeana) and Bladderwrack (Fucus spp.) in whole, flakes or powdered form. We also sell Seaweed Bath Pouches and all natural Kelp soap.


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