The Myriad Benefits of Seaweed

Seaweed – Antidiabetic, Anti-inflammatory and a Great Daily Supplement for All-Round Health

Our knowledge of the effects of seaweed species on health is still somewhat in its infancy but a raft of recent publications has uncovered some surprising potential benefits of seaweed. Brown seaweed (Ascophyllum nodosum and Fucus vesiculosus), for example, are being investigated for their use in blood sugar regulation and for inhibiting inflammation, thrombosis, and even tumour development, and such benefits are in addition to the impressive array of nutrients found in brown seaweeds. A popular ingredient in many green juices and powders, Ascophyllum nodosum and Fucus vesiculosus provide an alkalising effect and can help with detoxification. These nutrient-rich green foods contain a plethora of vitamins, minerals, amino acids, and antioxidants that can support the health of the digestive system, immune system, skin, hair and nails, and overall health and wellbeing.


Seaweed, Iodine and Thyroid Health

Specifically, seaweeds tend to be high in iodine, a mineral that is essential for healthy thyroid function. The thyroid is a gland in the neck that regulates metabolism, thereby having an impact on our energy levels, body weight, and even things like hair growth and cognitive function. A dysfunctional and underperforming thyroid gland can leave us tired, lethargic, easily confused and experiencing hair loss, while an overactive thyroid can cause dramatic weight loss, irritability and hyperactivity, and extreme sensitivity to stress. Managing iodine levels is key to maintaining good thyroid function but many people fail to consume sufficient iodine on a daily basis. Sea vegetables like Ascophyllum nodosum and Fucus vesiculosus can be a great source of iodine and other minerals and vitamins that also support thyroid health and overall metabolism. Too much iodine can, however, be a bad thing and so anyone with thyroid dysfunction should consult their physician prior to using iodine supplements or natural products that contain iodine. Meeting suggested iodine intake isn't the only benefit of seaweed though, and two of the most studied seaweeds, Ascophyllum nodosum and Fucus vesiculosus have been found to have some surprising effects on human biology.

The Best Kinds of Beneficial Seaweed  Ascophyllum nodosum is a large brown alga in the family Fucaceae, and is the only species in the genus Ascophyllum. This seaweed is found in the northern Atlantic Ocean and is also known as rockweed, Norwegian kelp, knotted kelp, knotted wrack or egg wrack.

The Seagreens® Ascophyllum nodosum is sourced from the Scottish Outer Hebrides and is especially high in iodine (typically providing 700mcg iodine per 1g). This seaweed is also rich in potassium, calcium, magnesium, and sulphur, as well as manganese, copper, iron, and zinc. Fucus vesiculosus meanwhile is commonly known as bladderwrack, black tang, rockweed, bladder fucus, sea oak, black tany, cut weed, dyers fucus, red fucus and rock wrack. It is found on the coasts of the North Sea, the western Baltic Sea and the Atlantic and Pacific Oceans and is rich in mucilage, algin, mannitol, polysaccharides, beta-carotene, zeaxanthin, bromine, potassium, volatile oils, iodine and many other minerals.

Seaweed Polysaccharides – A New Weapon in the Fight Against Diabetes?

The polysaccharides in these seaweeds have been studied for their effects on postprandial blood glucose, meaning the level of sugar in the blood after eating a meal. Researchers have found that constituents of Ascophyllum nodosum and Fucus vesiculosus inhibit the enzymes alpha-amylase and alpha-glucosidase which are key to the breakdown of carbohydrates. In a 2011 randomised, double-blind, placebo-controlled trial 23 people were given either a placebo or two 250mg capsules containing a blend of Ascophyllum nodosum and Fucus vesiculosus 30 minutes prior to eating bread containing 50g of carbohydrates. Blood glucose and insulin levels were assessed during the next three hours and those receiving the seaweed were found to have a 12.1% reduction in the insulin increase and a 7.9% increase in insulin sensitivity (Paradis et al., 2011). In another study 15 seaweeds were tested for their ability to inhibit alpha-amylase and alpha-glucosidase and Fucus vesiculosus Linnaeus was found to be the most potent inhibitor of alpha-glucosidase while Ascophyllum nodosum had the strongest alpha-amylase inhibitory effect (Lordan et al., 2013). These effects were associated with these seaweed species having the highest levels of polyphenols and antioxidants.

Seaweed’s Antioxidants and a Anti-inflammatory effects

In other studies Ascophyllum nodosum and Fucus vesiculosus have been found to protect against oxidative stress, including that which causes damage to DNA (O'Sullivan et al., 2012), and to influence levels of nitric oxide leading to a reduction in inflammation (Yang et al., 2006). There's still some way to go to determine just how beneficial brown seaweeds like bladderwrack and rockweed can be, but the research so far points to significant benefits of seaweed for controlling blood sugar and inflammation. As these seaweeds also provide a range of nutrients, including iodine, they are ideal for many for inclusion in a daily cleansing and detoxification regime.


Cumashi, A., et al., (2007). A comparative study of the anti-inflammatory, anticoagulant, antiangiogenic, and antiadhesive activities of nine different fucoidans from brown seaweeds. Glycobiology, May;17(5):541-52. Lordan, S., et al., (2013). The a-amylase and a-glucosidase inhibitory effects of Irish seaweed extracts. Food Chem, Dec 1;141(3):2170-6. O'Sullivan, A.M., et al., (2012). Assessment of the ability of seaweed extracts to protect against hydrogen peroxide and tert-butyl hydroperoxide induced cellular damage in Caco-2 cells. Food Chem, Sep 15;134(2):1137-40. Paradis, M.E., et al., (2011). A randomised crossover placebo-controlled trial investigating the effect of brown seaweed (Ascophyllum nodosum and Fucus vesiculosus) on postchallenge plasma glucose and insulin levels in men and women. Appl Physiol Nutr Metab, Dec;36(6):913-9. Yang, J.W., et al., (2006). Bifunctional effects of fucoidan on the expression of inducible nitric oxide synthase. Biochem Biophys Res Commun, Jul 21;346(1):345-50.