Edible marine algae has been a part of culinary traditions around the world for centuries. Wakame (Undaria pinnatifida), a marine algae indigenous to the cold, coastal waters of the Pacific, has been used as a food and medicinally in Japan and Korea for over a thousand years. Another marine algae, Ecklonia cava (also known as paddle weed), has also been part of these nations’ traditional diets. Dulse (Palmaria palmata), found primarily in northern Atlantic coastal areas, is an edible reddish brown algae. It was mentioned in 11th century Icelandic sagas and referenced in 18th century media in Ireland. The edible marine algae bladderwrack (Fucus vesiculosis) was commonly eaten for its iodine content in the early 1800s in North America.
In recent years, researchers have begun to quantify what many traditional cultures recognized instinctively: edible marine algaes have medicinal properties. One reason marine algaes have been so valued is because of their high mineral content. One serving of kelp (Ascophyllum nodosum) contains a quarter of the daily recommended intake of calcium and magnesium, almost that much copper, half the day’s requirement for iron, and over 40 times the reference nutrient intake of iodine.1 Lithothamnion calcareum, known colloquially as “maerl” in France, is highly sought after as a mineral supplement. An in vivo study showed that it improved bone mineral density in mice.2 Wakame is mineral-rich as well, containing ample amounts of iodine, calcium, magnesium, sodium, and phosphorus.3 Dulse contains not only the essential minerals calcium, potassium, magnesium, and sodium, but also trace minerals copper, iron, iodine, and zinc.4 Algas calcareas, found in coastal waters off South America, is especially rich in a form of calcium that is more easily absorbed by the body than most other commercial forms of this mineral; it has been shown in clinical trials to increase bone density.5,6
Edible marine algaes also contain natural anti-inflammatory and antioxidant compounds. Kelp contains fucoidan, which has been shown to dampen inflammation in vivo.7,8 Phlorotannins in Ecklonia cava suppress inflammation through several different pathways.9 Ecklonia also contains phlorotannins and polyphenols that are potent antioxidants.10,11 In spirulina, the pigment phycocyanin is the primary antioxidant.12 Spirulina decreases oxidation and protects cells from free radicals in vitro13,14 and raises plasma antioxidant levels in vivo.15 This alga also has anti-inflammatory properties, inhibiting liver inflammation in patients with non-alcoholic steatohepatitis16 and reversing arthritis-related inflammation in mice.17 The antioxidant properties in bladderwrack come from carotenoids18 and from the polysaccharide fucoxanthin.19 Dunaliella, too, contains carotenoids, contributing to its antioxidant effects.20 Dulse contains polyphenols, which are believed to be responsible for its antioxidant properties.21
Researchers have also investigated marine algaes for their anti-cancer properties.
Dulse shows anti-proliferative qualities in vitro.22,23 Dunaliella has shown anti-tumor effects in animal studies.24,25 In vitro studies on the fucoxanthin from wakame suggest it may have anti-proliferative, apoptotic effects.26,27 An extract from Ecklonia cava shows anti-proliferative effects in vitro; researchers theorize it works by interfering with cancer-associated enzyme activity.28 In mice, the polyphenols in ecklonia reduced skin cancer tumors by interfering with the COX-2 pathway.29 Lithothamnion calcareum may help prevent colon cancer by preventing inflammation and colon polyps, according to animal models.30 Fucoidan in bladderwrack also shows promise against cancer. In vitro it induces apoptosis.31,32 Mice injected with fucoidan show increased natural killer cell activity.33
marine algae may be helpful in the treatment of diabetes, according to animal models. Kelp lowers fasting blood sugar levels in rats34, spirulina helps normalize blood sugar levels in rats,35 and the fucoidan in wakame lowers blood sugar levels and reduces body weight in mice.36
Edible marine algaes also confer cardiovascular benefits. Spirulina improves overall cholesterol profiles in human clinical trials.37,38 Wakame has been shown to lower triglyceride levels in rats.39 A phlorotannin in Ecklonia cava functions as a natural ACE inhibitor, which can help lower blood pressure.40 Dunaliella supports healthy arteries by reducing vascular smooth muscle cell proliferation, a condition associated with narrowing of the arteries.41 Carotenoids, such as those found in dunaliella, have been shown to protect against atherosclerosis.42 Two marine algae species, bladderwrack and wakame, also have natural anti-coagulation effects. In bladderwrack, the active compound is fucoidan. When compared to the prescription drug heparin, fucoidan had greater anti-clotting activity43 while simultaneously inhibiting excessive bleeding.44 Wakame, too, has similar anti-clotting properties and fewer side effects than heparin.45
The liver can also benefit from marine algae’s effects. In vitro research suggests that Ecklonia cava can help protect the liver from fibrosis.46 In vivo studies involving rodents demonstrate that dunaliella protects against liver toxicity.47,48,49 In clinical trials, hepatitis patients were given spirulina for six months; by the end of the trial, they showed significant decreases in their viral load.50
Some marine algaes have anti-viral properties. In clinical trials, study participants with herpes experienced fewer symptoms and faster healing when given wakame.51 Additional research shows that the anti-herpes compound in wakame is likely fucoidan, and is effective against herpes simplex 1 and 2 as well as human cytomegalovirus.52 In vitro research has shown Ecklonia cava to block HIV-1 reverse transcriptase, which is necessary for the HIV virus to replicate.
marine algae helps a myriad of health conditions. In rodent models, spirulina has been shown to protect brain progenitor cells from acute inflammation,53 protect against damage from Parkinson’s disease,54 and reduce amyloid beta protein deposits associated with Alzheimer’s disease.55 Ecklonia cava interferes with processes associated with asthma attacks56 and reduces allergic response to IgE allergens in vitro.57
Kelp helps boost immune response; in an in vivo experiment, kelp extract injected into mice boosted splenic natural killer cell activity.58 Compounds in wakame have been shown to reduce body weight in animal models.59,60 The fucoidan in bladderwrack may also be useful for weight loss. It inhibits glucose uptake into fat cells and helps to break down fat.61
1 MacArtain, P., et al. Nutritional value of edible marine algaes. Nutrition Reviews. 2007. 65 (12), 535-543.
2 Aslam, M.N., et al. A mineral-rich extract from the red marine algae Lithothamnion calcareum preserves bone structure and function in female mice on a western-style diet. Calcified Tissue International. 2010. 86 (4), 313-324.
4 MacArtain, P., et al. Nutritional Value of Edible marine algaes. Nutrition Reviews. 2007. 65 (12), 535-543.
5 Michalek, J., et al. Changes in total body bone mineral density following a common bone health plan with two versions of a unique bone health supplement: a comparative effectiveness research study. Nutrition Journal. 2011. 10 (32).
6 Kaats, G.R., et al. A comparative effectiveness study of bone density changes in women over 40 following three bone health plans containing variations of the same novel plant-sourced calcium. International Journal of Medical Sciences. 2011. 8 (3), 180-191.
7 Kyung, J., et al. Synergistic anti-inflammatory effects of Laminaria japonica and Cistanche tubulosa extract. Laboratory Animal Research. 2012. 28 (2), 91-97.
8 Mizuno, M., et al. Different suppressive effects of fucoidan and lentinan on IL-8 mRNA expression in in vitro gut inflammation. Bioscience, Biotechnology, and Biochemistry. 2009. 73 (10), 2324-2325.
9 Shibata, T., et al. Inhibitory effects of brown algal phlorotannins on secretory phospholipase A2s, lipoxygenases and cyclooxygenases. Journal of Applied Phycology. 2003. 15, 61-66.
10 Athukorala, Y., et al. Antiproliferative and antioxidant properties of an enzymatic hydrolysate from brown alga, Ecklonia cava. Food and Chemical Toxicology. 2006. 44, 1065-1074.
11 Kang, S.M., et al. Evaluation of antioxidant properties of a new compound, pyrogallol-phloroglucinol-6,6′-bieckol isolated from brown algae, Ecklonia cava. Nutrition Research and Practice. 2011. 5(6), 495-502.
12 Pinero Estrada, J.E., et al. Antioxidant activity of different fractions of Spirulina platensis protean extract. Il Farmaco. 2001. 56, 497-500.
13 Miranda, M.S., et al. Antioxidant activity of the microalga Spirulina maxima. Brazilian Journal of Medical and Biological Research. 1998. 31: 1075-1079.
14 Chu, W.L., et al. Protective effect of aqueous extract from Spirulina platensis against cell death induced by free radicals. BMC Complementary and Alternative Medicines. 2010. 10:53.
15 Miranda, M.S., et al. Antioxidant activity of the microalga Spirulina maxima. Brazilian Journal of Medical and Biological Research. 1998. 31: 1075-1079.
16 Pak, W., et al. Anti-oxidative and anti-inflammatory effects of spirulina on rat model of non-alcoholic steatohepatitis. Journal of Clinical Biochemistry and Nutrition. 2012. 51 (3), 227-234.
17 Rasool, M., et al. Anti-inflammatory Effect of Spirulina fusiformis on Adjuvant-Induced Arthritis in Mice. Biological & Pharmaceutical Bulletin. 2006. 29 (12), 2483-2487.
18 Haugan, J.A.; Liaaen-Jensen, S. Algal carotenoids 54. Carotenoids of brown algae (phaeophyceae). Biochemical Systematics and Ecology. 1994, 22, 31–41.
19 Rocha de Souza, M.C., et al. Antioxidant activities of sulfated polysaccharides from brown and red marine algaes. Journal of Applied Phycology. 2007. 19:153-160.
20 Chidambara Murthy, K.N. In vivo antioxidant activity of carotenoids from Dunaliella salina–a green microalga. Life Sciences. 2005. 76 (12), 1381-1390.
21 Yuan, Y. and Walsh, N.A. Antioxidant and antiproliferative activities of extracts from a variety of edible marine algaes. Food and Chemical Toxicology. 2006. 44 (7), 1144-1150.
22 Yuan , Y., et al. Extracts from dulse (Palmaria palmata) are effective antioxidants and inhibitors of cell proliferation in vitro. Food and Chemical Toxicology. 2005. 43, 1073–1081.
23 Yuan, Y. and Walsh, N.A. Antioxidant and antiproliferative activities of extracts from a variety of edible marine algaes. Food and Chemical Toxicology. 2006. 44 (7), 1144-1150.
24 Raja, R., et al. Protective effect of Dunaliella salina (Volvocales, Chlorophyta) against experimentally induced fibrosarcoma on wistar rats. Microbiological Research. 2007. 162 (2), 177-184.
25 Nagasawa, H., et al. Inhibition by beta-carotene-rich algae Dunaliella of spontaneous mammary tumourigenesis in mice. Anticancer Research. 1989. 9 (1), 71-75.
26 Liu, C.L., et al. Fucoxanthin enhances cisplatin-induced cytotoxicity via NF?B-mediated pathway and downregulates DNA repair gene expression in human hepatoma HepG2 cells. Marine Drugs. 2013. 11, 50-66.
27 Hosokawa, M., et al. Apoptosis-inducing effect of fucoxanthin on human leukemia cell line HL-60. Food Science and Technology Research. 1999. 5 (3), 243-246.
28 Chen Zhang, et al. Dieckol from Ecklonia cava Regulates Invasion of Human Fibrosarcoma Cells and Modulates MMP-2 and MMP-9 Expression via NF-?B Pathway. Evidence-Based Complementary and Alternative Medicine. 2011, Article ID 140462.
29 Hwang, H., et al. Photochemoprevention of UVB-induced skin carcinogenesis in SKH-1 mice by brown algae polyphenols. International Journal of Cancer. 2006. 119, 2742-2749.
30 Aslam, M.H., et al. A mineral-rich red algae extract inhibits polyp formation and inflammation in the gastrointestinal tract of mice on a high-fat diet. Integrative Cancer Therapies. 2010. 9 (1), 93-99.
31 Ale, M.T., et al. Fucoidan from Sargassum sp. and Fucus vesiculosus reduces cell viability of lung carcinoma and melanoma cells in vitro and activates natural killer cells in mice in vivo. International Journal of Biological Macromolecules. 2011. 49, 331-336.
32 Ale, M.T., et al. Fucose-containing sulfated polysaccharides from brownmarine algaes inhibit proliferation of melanoma cells and induce apoptosis by activation of caspase-3 in vitro. Marine Drugs. 2011. 9, 2605-2621.
33 Ale, M.T., et al. Fucose-containing sulfated polysaccharides from brownmarine algaes inhibit proliferation of melanoma cells and induce apoptosis by activation of caspase-3 in vitro. Marine Drugs. 2011. 9, 2605-2621. Long, S.H., et al. The hypoglycemic effect of the kelp on diabetes mellitus
34 model induced by alloxan in rats. International Journal of Molecular Sciences. 2012. 13, 3354-3365. Jarouliya, U., et al. Alleviation of metabolic abnormalities induced by excessive fructose administration in Wistar rats by Spirulina maxima. Indian Journal of Medical Research. 2012. 135 (3), 422-428.
35 Jarouliya, U., et al. Alleviation of metabolic abnormalities induced by excessive fructose administration in Wistar rats by Spirulina maxima. Indian Journal of Medical Research. 2012. 135 (3), 422-428.
36 Jeong, Y.T., et al. Low molecular weight fucoidan (LMWF) improves ER stress-reduced insulin sensitivity through AMPK activation in L6 myotubes and restores lipid homeostasis in a mouse model of type 2 diabetes. Molecular Pharmacology. 2013. Doi:10.1124/mol.113.085100.
37 Torres-Duran, P.V., et al. Antihyperlipemic and antihypertensive effects of Spirulina maxima in an open sample of Mexican population: a preliminary report. Lipids in Health and Disease. 2007. 6:33.
38 Torres-Duran, P.V., et al. Effect of Spirulina maxima on Postprandial Lipemia in Young Runners: A Preliminary Report. Journal of Medicinal Food. 2012. 15 (8), 753-757.
39 Murata, M., et al. Hepatic fatty acid oxidation enzyme activities are stimulated in rats fed the brown marine algae, Undaria pinnatifida (wakame). The Journal of Nutrition. 1999. 129, 146-151.
40 Wijesinghe, W., et al. Effect of phlorotannins isolated from Ecklonia cava on angiotensin I-converting enzyme (ACE) inhibitory activity. Nutrition Research and Practice. 2011. 5 (2), 93-100.
41 Sheu, M.J., et al. Molecular mechanism of green microalgae, Dunaliella salina, involved in attenuating balloon injury-induced neointimal formation. British Journal of Nutrition. 2010. 104 (3), 326-335.
42 Karppi, J., et al. Serum carotenoids reduce progression of early atherosclerosis in the carotid artery wall among eastern Finnish men. PLoS One. 2013. 8 (5). doi:10.1371/journal.pone.0064107
43 Kwak, K.W., et al. Biological effects of fucoidan isolated from Fucus vesiculosus on thrombosis and vascular cells. The Korean Journal of Hematology. 2010. 45 (1), 51-57.
44 Min, S.K., et al. An antithrombotic fucoidan, unlike heparin, does not prolong bleeding time in a murine arterial thrombosis model: a comparative study of Undaria pinnatifida sporophylls and Fucus vesiculosus. Pharmacology Research & Perspectives. 2012. 26 (5), 752-757.
45 Kim, W.J., et al. Purification and anticoagulant activity of a fucoidan from Korean Undaria pinnatifida sporophyll. Algae. 2007. 22 (3), 247-252.
46 Yokogawa, K., et al. Inhibitory Effects of Ecklonia cava Extract on High Glucose-Induced Hepatic Stellate Cell Activation. Marine Drugs. 2011. 9, 2793-2808.
47 Hsu, Y.W., et al. Protective effects of Dunaliella salina–a carotenoids-rich alga, against carbon tetrachloride-induced hepatotoxicity in mice. Food and Chemical Toxicology. 2008. 46 (10), 3311-3317.
48 Chidambara Murthy, K.N., et al. Protective effect of Dunaliella salina–A marine micro alga, against carbon tetrachloride-induced hepatotoxicity in rats. Hepatology Research. 2005. 33 (4), 313-319.
49 Murthy, K.N. Comparative evaluation of hepatoprotective activity of carotenoids of microalgae. Journal of Medical Food. 2005. 8 (4), 523-528.
50 Yakoot, M., and Salem, A. Spirulina platensis versus silymarin in the treatment of chronic hepatitis C virus infection. A pilot randomized, comparative clinical trial. BMC Gastroenterology. 2012. 12 (32).
51 Cooper, R., et al. GFS, a preparation of Tasmanian Undaria pinnatifida is associated with healing and inhibition of reactivation of Herpes. BMC Complementary and Alternative Medicine. 2002. 2 (11).
52 Lee, J.B., et al. Novel antiviral fucoidan from sporophyll of Undaria pinnatifida (Mekabu). Chemical and Pharmaceutical Bulletin. 2004. 52 (9), 1091-1094.
53 Bachstetter, A., et al. Spirulina Promotes Stem Cell Genesis and Protects against LPS Induced Declines in Neural Stem Cell Proliferation. PLoS ONE. 2010. 5 (5).
54 Pabon, M.M., et al. A Spirulina-Enhanced Diet Provides Neuroprotection in an alpha–Synuclein Model of Parkinson’s Disease. PLoS ONE. 2012. 7 (9).
55 Hwang, J.H., et al. Spirulina Prevents Memory Dysfunction, Reduces Oxidative Stress Damage, and Augments Antioxidant Activity in Senescence-Accelerated Mice. Journal of Nutritional Science and Vitaminology. 2011. 57, 186-191.
56 Kim, S.K., et al. Effects of Ecklonia cava ethanolic extracts on airway hyperresponsiveness and inflammation in a murine asthma model: role of suppressor of cytokine signaling. Biomedicine and Pharmacotherapy. 2008. 62 (5), 289-296.
57 Shim, S.Y., et al. Ecklonia cava extract suppresses the high-affinity IgE receptor, Fc epsilon RI expression. Food and Chemical Toxicology. 2009. 47 (3), 555-560.
58 Nakano, K., et al. Immunostimulatory activities of the sulfated polysaccharide ascophyllan from Ascophyllum nodosum in in vivo and in vitro systems. Bioscience, Biotechnology, and Biochemistry. 2012. 76 (8), 1573-1576.
59 Jeong, Y.T., et al. Low molecular weight fucoidan (LMWF) improves ER stress-reduced insulin sensitivity through AMPK activation in L6 myotubes and restores lipid homeostasis in a mouse model of type 2 diabetes. Molecular Pharmacology. 2013. Doi:10.1124/mol.113.085100.
60 Maeda, H., et al. Effect of medium-chain triacylglycerols on anti-obesity effect of fucoxanthin. Journal of Oleo Science. 2007. 56 (12), 615-621.
61 Park, M.K., et al. Fucoidan from marine brown algae inhibits lipid accumulation. Marine Drugs. 2011. 9, 1359-1367.
