Seaweed as an ingredient is growing in popularity largely due to its perceived health-giving properties supported by findings from epidemiological studies.

Increased seaweed consumption has been linked to reduced risk of various diseases however there is a paucity of evidence for health benefits derived from robust randomised controlled trials (RCT). Emerging data from short-term RCT

involving seaweed isolates are promising. Further investigation of seaweed as a wholefood ingredient is warranted. This review aims to highlight the food uses

and potential health benefits of seaweeds

Brownlee, Iain

Fairclough, Andrew

Hall, Anna

Paxman, Jenny

English

Sheffield Hallam University Research Archive

Dietary seaweed and human healthBROWNLEE, Iain, FAIRCLOUGH, Andrew, HALL, Anna and PAXMAN, JennyAvailable from Sheffield Hallam University Research Archive (SHURA) at:http://shura.shu.ac.uk/4978/This document is the author deposited version.  You are advised to consult the publisher's version if you wish to cite from it.Published versionBROWNLEE, Iain, FAIRCLOUGH, Andrew, HALL, Anna and PAXMAN, Jenny (2011). Dietary seaweed and human health. In: Culinary Arts and Sciences VII:Global, National and Local Perspectives. Bournemouth University UK, Bournemouth University International Centre for Tourism and Hospitality Research, 82-88.Repository use policyCopyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Users may download and/or print one copy of any article(s) in SHURA to facilitate their private study or for non-commercial research. You may not engage in further distribution of the material or use it for any profit-making activities or any commercial gain.Sheffield Hallam University Research Archivehttp://shura.shu.ac.uk Dietary Seaweed and Human Health Brownlee, I.A., Fairclough, A.C., Hall, A.C. and Paxman, J.R. Centre for Food Innovation, Sheffield Hallam University, Howard St, Sheffield, S1 1WB.  Introduction  For centuries seaweed has been consumed in Asia1; however, it is not a usual part of the Western diet.  A recent move to introduce seaweed into European cuisine has met with limited success though it has gained acceptance in some Westernised cultures such as California and Hawaii, where there are large Japanese communities who have had a tangible influence on local dietary practices.  Low consumer awareness regarding the potential health benefits of seaweed challenges its use in the daily diet2. Not surprisingly therefore consumption of seaweed in the UK is minimal at present3 though there appears to be no reliable intake data from routine dietary surveys4.  In the USA and Canada, seaweed is cultivated in onshore tanks and the market is growing.  In Ireland there is renewed interest in seaweed that once formed part of the traditional diet.  Recipe books promoting the use of 'sea vegetables' or 'marine vegetables'5 in home-cooking are becoming more popular.  Consumer health and nutrition are becoming increasingly influential in the food industry, thus seaweed is gaining in popularity5, and associated product development appears to be slowly evolving.  Seaweeds are macroalgae; subclassified as brown (phaeophyta), red (rhodophyta) or green (chlorophyta), some of which are edible, and blue-green algae (cyanophyta), which are toxic6.  To date, seaweed as a 'whole-food' has been added to pasta7, bread8,9, and processed (Fairclough, personal communication) and low fat meats10.    Nutritional profile and acceptability of seaweed  Habitual consumption of seaweed may offer a nutritionally rich addition to the diet; however, micronutrient intakes in excess of the RNI may be of concern to nutritionists, particularly where bioavailability is high.  Previous authors have eloquently reported the nutritional value of 9 common edible seaweeds 6.  The rich mineral and trace element content of seaweed compared to terrestrial foods can however, impact negatively on its organoleptic characteristics6.  However, it has been shown to be acceptable to consumers when baked into breads (Ascophyllum nodosum up to 5% w/w; Hall et al., 20109; Mahadevan and Fairclough, personal communication) and added to pasta (Undaria pinnatifida up to 10% w/w7).  Seaweed is high in fibre and contains many other potentially "bioactive" compounds6.  Collectively, these results suggest that seaweed may be successfully combined into acceptable food products to potentially enhance their nutritional quality.   Seaweed as a whole-food  Observational evidence linking seaweed intake to reduced disease risk is currently only relevant in South East Asian populations where seaweed is habitually consumed. Recent data are summarised in Table 1.  In humans, an inverse correlation between seaweed consumption (Alaria esculenta (L.)) and serum oestradiol was demonstrated in a recent randomised controlled trial14 which may in part explain epidemiology linking seaweed intake with reduced risk of hormone related diseases such as breast and endometrial cancers.  Rodophycaeae seaweed significantly reduced the glycaemic response to a carbohydrate load in a small sample of healthy females15 with possible implications for the management of type II diabetes and/or obesity.  Table 1. Summary of recent observational studies relating to dietary seaweed intake and health  Disease/health concern Study design Odds ratio (95% CI) of highest seaweed to lowest Reference Type II diabetes and pre-diabetes 3,405 Korean individuals, aged 20 - 65 y. retrospective study.  Adjusted for diet and lifestyle 0.66 (0.43-0.99) for men and 0.80 (0.51-1.24) for women 30 Osteoporosis 214 Japanese elderly participants. Prospective study assessing calcaneus stiffness changes over 5 years. No adjustment of data. 0.22 (0.07-67) in all individuals 31  Obesity 3760 Japanese women aged 18-20 y.  Cross-sectional study assessing 3 different eating patterns 0.57 (0.37-0.87) for BMI >25.0a 32 CV mortality 40547 Japanese men and women aged 40-79 y. prospective study over seven years of follow-up. Not adjusted 0.73 (0.59 -0.90)a 33  Allergic rhinosinusitis 1002 pregnant Japanese women. Cross-sectional study. Data adjusted for lifestyle and risk factors 0.51 (0.30–0.87) 34 Breast cancer occurrence South Korean case-control study.  362 cases (30-65y) with controls matched for age and menopausal status.  Data adjusted for multivitamin supplement use, number of children, breastfeeding, dietary factors, education, exercise, oral contraceptive use. 0.48 (0.27-0.86)  35 a Seaweed was included as part of a healthy/traditional Japanese eating pattern (i.e. high intakes of vegetables, mushrooms, seaweeds, potatoes, fish and shellfish, soy products, processed fish, fruit and salted vegetables) and was not assessed independently. CV = cardiovascular The antimicrobial properties of seaweed isolates have been well documented16-18; however, there is a paucity of data on the antimicrobial properties and preservative effects of seaweed as a 'whole-food' ingredient.  In processed meat products (3% w/w incorporation) we have shown Ascophyllum nodosum to elicit an antimicrobial effect.  These were most noticeable against specific types of Gram negative micro-organisms (Fairclough, personal communication).  Interestingly seaweed isolates have been shown to act more favourably against Gram positive organisms17,19.  We added Ascophyllum nodosum  to preservative-free wholemeal bread ( 1.25% w/w) as a replacement for salt (as sodium chloride) with an associated suppression of mould growth up to 9 days compared to  3 days for the control bread (containing 5 g sodium chloride without seaweed) (Fairclough, personal communication).  Such applications may be of considerable interest to food industries aiming to meet public health recommendations to voluntarily reduce the salt content of processed foods.  Seaweed isolates  Isolated viscous seaweed polysaccharides are frequently used by the food industry in a wide variety of applications to benefit texture and stability20.  In molecular gastronomy, such novel polysaccharides also present structural advantages in the production of foams and mousses, and allow both direct and reverse spherification.  The above applications of seaweed polysaccharides benefit the organoleptic quality of foods. Experimental data exists suggesting that such factors, when used at higher concentrations, could benefit human health. For instance, alginate incorporation into foods and/or beverages has been shown to benefit acute physiological effects of meal consumption including reducing hunger and food intake and enhancing satiety21-24, improving glycaemic control21,22 and reducing fat absorption24,25.  Similar results have been reported in animal-feeding studies (reviewed elsewhere1, 26).    Potential negative effects of consuming seaweed or seaweed isolates  Components of seaweed bind to and adsorb heavy metals27, meaning that seaweed is particularly prone to contamination from polluted water and its consumption is a potential route of heavy metals entering the body.  Additionally, toxic blue-green algae species may grow on edible seaweed and have been noted in the literature to be a causative factor in food poisoning occurrences28.  Alginates and other seaweed isolates bind to divalent cations, which could affect the bioavailability of dietary calcium, iron and some trace elements (reviewed elsewhere26). High consumption of seaweed in Japan and Korea by lactating mothers has been linked to neonatal iodine toxicity and consequent hypothroidism29. High iodine intake is also not advisable in thyroid patients. Given the low levels of consumption of seaweed in the West, such concerns are of little public health relevance at present, although accurate dietary intake data for monitoring purposes would be useful in the light of increasing popularity with consumers.  Summary  Seaweed may be an important ingredient across many public health disciplines including environmental sustainability, food safety, nutrition and health.   This information may be beneficial for policy makers, practitioners, researchers and academics who contribute to the promotion of public health.   Existing evidence presents a compelling argument for moderate inclusion of seaweed in the Western diet.  However, long-term intervention studies (particularly well-powered, appropriately designed randomised-controlled trials) are necessary to assess whether dietary seaweed/seaweed fibre impacts positively on human health.    References  1. Jiménez-Escrig A, Sánchez-Muniz FJ. Dietary fibre from edible seaweeds: Chemical structure, physicochemical properties and effects on cholesterol metabolism. Nutr.Res. 2000;20(4):585-598.  2. Kadam SU, Prabhasankar P. Marine foods as functional ingredients in bakery and pasta products. Food Res.Int. 2010;43(8):1975-1980.  3. Rose M, Lewis J, Langford N, Baxter M, Origgi S, Barber M, et al. Arsenic in seaweed-Forms, concentration and dietary exposure. Food and Chemical Toxicology 2007;45(7):1263-1267.  4. Bates, C. Lennox, A. Swan, G. National Diet and Nutrition Survey: Headline Results from Year 1 of the Rolling Programme (2008/09). 2009.  5. Lee B. Seaweed: Potential as a marine vegetable and other opportunities. 2008.  6. MacArtain P, Gill CIR, Brooks M, Campbell R, Rowland IR. Nutritional value of edible seaweeds. Nutr.Rev. 2007;65(12):535-543.  7. Prabhasankar P, Ganesan P, Bhaskar N, Hirose A, Stephen N, Gowda LR, et al. Edible Japanese seaweed, wakame (Undaria pinnatifida) as an ingredient in pasta: Chemical, functional and structural evaluation. Food Chem. 2009;115(2):501-508.  8. Guarda A, Rosell CM, Benedito C, Galotto MJ. Different hydrocolloids as bread improvers and antistaling agents. Food Hydrocoll. 2004;18(2):241-247.  9. Hall, A.C., Fairclough, A., Mahadevan, K. and Paxman, J.R. Seaweed (Ascophyllum nodosum) enriched bread is acceptable to consumers (ABSTRACT). P. Nutr. Soc. 2010;69:E352.  10. López-López I, Bastida S, Ruiz-Capillas C, Bravo L, Larrea MT, Sánchez-Muniz F, et al. Composition and antioxidant capacity of low-salt meat emulsion model systems containing edible seaweeds. Meat Sci. 2009;83(3):492-498.  11. Wong KH, Sam SW, Cheung PCK, Ang Jr. PO. Changes in lipid profiles of rats fed with seaweed-based diets. Nutr.Res. 1999;19(10):1519-1527.  12. Bocanegra A, Benedí J, Sánchez-Muniz FJ. Differential effects of konbu and nori seaweed dietary supplementation on liver glutathione status in normo- and hypercholesterolaemic growing rats. Br.J.Nutr. 2006;95(4):696-702.  13. Bocanegra A, Bastida S, Benedí J, Nus M, Sánchez-Montero JM, Sánchez-Muniz FJ. Effect of seaweed and cholesterol-enriched diets on postprandial lipoproteinaemia in rats. Br.J.Nutr. 2009;102(12):1728-1739.  14. Teas J, Hurley TG, Hebert JR, Franke AA, Sepkovic DW, Kurzer MS. Dietary seaweed modifies estrogen and phytoestrogen metabolism in healthy postmenopausal women (Journal of Nutrition (2009) 139 (939-944)). J.Nutr. 2009;139(9):1779.  15. Goi I, Valdivieso L, Garcia-Alonso A. Nori seaweed consumption modifies glycemic response in healthy volunteers. Nutr.Res. 2000;20(10):1367-1375.  16. Bansemir A, Blume M, Schröder S, Lindequist U. Screening of cultivated seaweeds for antibacterial activity against fish pathogenic bacteria. Aquaculture 2006;252(1):79-84.  17. Braden KW, Blanton Jr. JR, Allen VG, Pond KR, Miller MF. Ascophyllum nodosum supplementation: A preharvest intervention for reducing Escherichia coli O157:H7 and Salmonella spp. in feedlot steers. J.Food Prot. 2004;67(9):1824-1828.  18. Yuan YV, Walsh NA. Antioxidant and antiproliferative activities of extracts from a variety of edible seaweeds. Food and Chemical Toxicology 2006;44(7):1144-1150.  19. Hellio C, Bremer G, Pons AM, Le Gal Y, Bourgougnon N. Inhibition of the development of microorganisms (bacteria and fungi) by extracts of marine algae from Brittany, France. Appl.Microbiol.Biotechnol. 2000;54(4):543-549.  20. Brownlee IA, Seal CJ, Wilcox M, Dettmar PW, Pearson JP. Applications of Alginates in Food. In: Rehm BHA, editor. Alginates: Biology and applications Berlin, Germany: Springer; 2009. p. 221-228.  21. Paxman JR, Richardson JC, Dettmar PW, Corfe BM. Alginate reduces the increased uptake of cholesterol and glucose in overweight male subjects: a pilot study. Nutr.Res. 2008;28(8):501-505.  22. Torsdottir I, Alpsten M, Holm G, Sandberg AS, Tolli J. A Small Dose of Soluble Alginate-Fiber Affects Postprandial Glycemia and Gastric Emptying in Humans with Diabetes. J. Nutr. 1991;121(795-799).  23. Hoad CL, Rayment P, Spiller RC, Marciani L, De Celis Alonso B, Traynor C, et al. In vivo imaging of intragastric gelation and its effect on satiety in humans. J.Nutr. 2004;134(9):2293-2300.  24. Paxman JR, Richardson JC, Dettmar PW, Corfe BM. Daily ingestion of alginate reduces energy intake in free-living subjects. Appetite 2008;51(3):713-719.  25. Sandberg AS, Andersson H, Bosaeus I, Carlsson NG, Hasselblad K, Harrod M. Alginate, Small-Bowel Sterol Excretion, and Absorption of Nutrients in Ileostomy Subjects. Am. J. Clin. Nutr. 1994;60(5):751-756.  26. Brownlee IA, Allen A, Pearson JP, Dettmar PW, Havler ME, Atherton MR, et al. Alginate as a source of dietary fiber. Critical Reviews in Food Science and Nutrition 2005;45(6):497-510.  27. Bailey SE, Olin TJ, Bricka RM, Adrian DD. A review of potentially low-cost sorbents for heavy metals. Water Res. 1999;33(11):2469-2479.  28. Marshall KLE, Vogt RL, Effler P. Illness associated with eating seaweed, Hawaii, 1994. West.J.Med. 1998;169(5):293-295.  29. Crawford, B.A., Cowell, C.T., Emder, P.J., Learoyd, D.L., Chua, E.L., Sinn, J. and Jack, M.M. Iodine toxicity from soy milk and seaweed ingestion is associated with serious thyroid dysfunction. Med. J. Aust. 2010;193:413-415.  30. Lee HJ, Kim HC, Vitek L, Nam MC. Algae consumption and risk of type 2 diabetes: Korean National Health and Nutrition Examination Survey in 2005. J.Nutr.Sci.Vitaminol. 2010;56(1):13-18.  31. Nakayama Y, Sakauchi F, Mori M. Risk factors for osteoporosis in elderly people with a cohort study - Using calcaneus stiffness as an index. Sapporo Medical journal 2008;76(4-6):33-40.  32. Okubo H, Sasaki S, Murakami K, Kim MK, Takahashi Y, Hosoi Y, et al. Three major dietary patterns are all independently related to the risk of obesity among 3760 Japanese women aged 18-20 years. Int.J.Obes. 2008;32(3):541-549.  33. Shimazu T, Kuriyama S, Hozawa A, Ohmori K, Sato Y, Nakaya N, et al. Dietary patterns and cardiovascular disease mortality in Japan: A prospective cohort study. Int.J.Epidemiol. 2007;36(3):600-609.  34. Miyake Y, Sasaki S, Ohya Y, Miyamoto S, Matsunaga I, Yoshida T, et al. Dietary Intake of Seaweed and Minerals and Prevalence of Allergic Rhinitis in Japanese Pregnant Females: Baseline Data From the Osaka Maternal and Child Health Study. Ann.Epidemiol. 2006;16(8):614-621.  35. Yang YJ, Nam S-, Kong G, Kim MK. A case-control study on seaweed consumption and the risk of breast cancer. Br.J.Nutr. 2010;103(9):1345-1353.  

Dietary seaweed and human health

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