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Seafood sustains a healthy diet

Charles Odilichukwu R. Okpala of the Educare & Skills Training Network and Ivan Bartolo of the Sea Fish Industry Authority discuss the desirability of seafood consumption and its merits for healthy living.

Introduction

Globally, seafood production and its consumption have been of increasing interest and diverse health benefits have been established. Whilst consumers see the desirability of seafood from different perspectives, many are inclined to focus on the merits/positives while others are concerned about the demerits/negatives. This article assesses some key facts of seafood desirability.

Seafood consumption: some basic facts 

According to the FAO’s State of the World Fisheries and Aquaculture 2016, seafood production in 2014 reached 167.2 million tonnes. Of this, 146.3 million tonnes were for direct human consumption, with aquaculture providing slightly more fish than capture fisheries. The figure includes fish (marine pelagic, marine demersal, diadromous, freshwater), molluscs (bivalves, gastropods, cephalopods), crustaceans (shrimps, crabs, lobsters, krill), other aquatic animals (aquatic mammals/reptiles, echinoderms, jelly fish) but excludes aquatic plants (seaweed, microphytes). Globally the supply of seafood has seen sustained growth thanks to production increases, reduced wastage, better utilisation and improved distribution[1].

Seafood consumption gives manifold health benefits. Fish and shellfish are a rich source of easily digested, high quality protein containing all the essential amino acids. They are also unusually rich in long chain omega-3 fatty acids, various vitamins (particularly A, D, B6 and B12) and several minerals. All are required as part of a healthy diet. The intake of protein through seafood consumption is crucial for the health of inhabitants of countries where the total protein intake is low, as in some developing coastal states[1].

Compared to other foods, seafood consumption is driven less by taste preferences and more by social norms, moral obligation and health. Regular seafood consumption from childhood results in a positive attitude towards seafood consumption in adulthood, whereas lack of familiarity with seafood and an absence of a history of seafood consumption can lead to a less positive attitude. Other drivers that promote the consumption of seafood include taste, convenience, diet variety, nutritional value, health benefits and the availability of fresh (quality) product. Barriers towards seafood consumption include price, convenience, knowledge of fresh seafood products and their availability. Insufficient understanding of the benefits of seafood and concerns about sustainability and quality also lead to negative attitudes to consumption. Consumer age positively relates with frequency of seafood consumption: older people tend to eat more seafood[2,3,4]. Table 1 lists some of the attitudes of UK consumers towards seafood in the context of other proteins.

Attitudes to fish are known to differ between purchasers and non-purchasers. Some people are reluctant to consume fish because of perceived difficulty of purchase, preparation and cooking, and the perceived unpleasant properties of fish, such as the presence of bones and fish smells during cooking[5]. Fish processors and retailers are aware of these barriers and encourage seafood purchases by formulating boneless products, often flavoured with sauces and requiring minimal preparation.

Table 1 Fish in the context of other key food proteins
Adapted from: Garrett, A. (2016). Fish as food: an initial review of developments,
implications and practical responses from industry and Seafish. Available at: http://
www.seafish.org/media/1644230/fish_as_food_lr.pdf (accessed on 13 April 2018)

Seafood preparation and presentation

Seafood is available to the consumer in many different formats. Unprocessed seafood is available live, fresh or frozen, and may be presented to the purchaser gutted, filleted, shelled, shucked etc., as well as still swimming in an aquarium. Because of its perishable nature,

Inspecting mussels on mussel-growing ropes. Aquaculture now provides most of the seafood we eat
Credit: Seafish (www.seafish.org)

seafood is very often preserved – by salting, smoking, marinating, canning, drying and fermenting – giving rise to stable products with individual organoleptic characteristics.

Consumer preference for the various preparations differs widely between countries and even regions. Chinese consumers tend to purchase fish and shellfish live because they want the guarantee of freshness and quality that only live seafood can offer. Generally speaking, purchasers in southern Europe prefer fresh products, while those in northern countries prefer preserved products. This reflects the broader global tendency for coastal populations to consume a wide variety of fresh fish whereas inland populations prefer a narrower range of fish products, mostly of the preserved type. There are some strong country-specific preferences some of which are well known, such as the British love of fish fingers and kippers. The UK has a preference for breaded product 15% above the European average, while together with Denmark it has the highest proportion of purchasers of smoked fish in Europe[6]. Some African countries (such as Mali, Gambia and Uganda) consume about half of their seafood as smoked product. Fermented and cured products are eaten in South East Asian countries and in northern European countries.

Surimi is made from lean minced whitefish meat that is rinsed multiple times in water and then mixed with additives (usually including egg white and flavour enhancers) to form a concentrated proteinaceous paste or gel. In the West, we recognise surimi as the main ingredient of crab meat analogues, but in Japan and other Eastern countries, surimi is widely consumed as a food in its own right or is used to make fish cakes (kamaboko) and other products[7].

As consumers look for quicker meal solutions and new product ideas, kitchen-ready convenience foods based on seafood are a growing sector. In the UK, they have helped raise seafood consumption especially among younger age groups, who are aware of the health benefits and are also keen to avoid handling and preparing seafood.

Notwithstanding the growing popularity of Japanese-style surimi and related raw seafood products, the vast majority of seafood is cooked before it is eaten. Seafood is fried, baked, grilled, poached, steamed or boiled. The different cooking processes not only make the raw material more palatable but they also destroy potentially harmful microorganisms and parasites, such as the Anisakis nematode. Fish intended to be eaten raw (e.g. sashimi) or almost raw (e.g. salmon intended for cold smoking) needs to undergo a process, usually freezing, to inactivate parasites and ensure they are not harmful.

Globally the supply of seafood has seen sustained growth thanks to production increases, reduced wastage, better utilisation and improved distribution.

Health aspects of seafood consumption

Seafood is an important constituent of many people’s diet and contributes a wealth of nutrients. Seafood is associated not only with positive aspects but also with a number of negative health aspects, such as contamination with heavy metals or dioxins, which may cause some consumers to avoid seafood. It is important to stress that with few exceptions, those consumers who reduce their consumption of seafood because of fears of negative health effects are doing themselves a disservice: in the words of Mozaffarian & Rimm[8]: ‘Avoidance of modest fish consumption due to confusion regarding risks and benefits could result in thousands of excess CHD (coronary heart disease) deaths annually and suboptimal neurodevelopment in children’.

Benefits of seafood consumption can include:

•Fish and shellfish are a rich source of easily digestible protein containing all the essential amino acids. This source of essential amino acids is critical for populations with high carbohydrate diets and with little access to animal protein.

•Fish and shellfish, and especially oily fish such as mackerel and herring, contain significant amounts of omega-3 fatty acids (also known as n-3 polyunsaturated fatty acids), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These have been shown to reduce significantly the risk of coronary death. DHA is essential for the foetal and early infant development of the brain and nervous system.

•Fish and shellfish are rich in several nutrients including calcium, iodine, zinc, iron and selenium.

Some possible adverse health effects of seafoods can include:

•Some people are allergic to fish, crustaceans and/or molluscs.

•Marine biotoxins, derived from marine algae or other microorganisms, may be present in certain seafood, typically bivalve molluscs. National food authorities worldwide are aware of the risks specific to their local areas and minimise these risks through measures, such as monitoring of harvesting areas, restricting harvesting to periods when toxic algae are absent or by on-shore product testing.

•Fish and shellfish can accumulate contaminants, particularly heavy metals and polyhalogenated organic pollutants.

•Mercury (Hg) can accumulate in larger fish, such as swordfish. Because of this, pregnant women in particular are advised to avoid such species and to eat other species instead[9].

•Cadmium (Cd) is widely known to accumulate in the hepatopancreas of crustaceans, while lead (Pb) will also accumulate in seafood and is avoided by ensuring that fishing activities take place away from polluted areas.

•Oily fish can accumulate polychlorinated and brominated organic pollutants, such as dioxins, which are pollutants left over from historical use of these chemicals. In most countries there is legislation in place to ensure that this risk is minimised.

•Fish smoking can introduce undesirable polycyclic aromatic hydrocarbons and this needs to be kept to a minimum through good smoking practices.

Take home message

The benefits of seafood intake for adults in particular outweigh the potential risks. Women of childbearing age also benefit from modest fish intake (at least one to two servings per week), though they are advised to avoid certain species.

However, children should be encouraged to eat fish because of the immediate health benefits and since early exposure to seafood is important for continued consumption. Avoiding seafood because of confusion about the health benefits would result in poorer overall health, especially in terms of coronary heart disease.

Charles Odilichukwu R. Okpala

Educare & Skills Training Network, Middlesex HA8 8EJ

Charles is a food scientist and independent researcher in innovative food science/processing and emerging technologies and holds an M.Res. in Food Sciences from the University of Strathclyde, Glasgow. He is Fellow of the Linnean Society of London (FLS), Fellow of the Institute of Food Science and Technology (FIFST), Chartered Scientist (CSci), and Professional Engineer (P.Eng.UK). Previously held research positions in notable institutions in Malaysia, UAE and Italy. He has contributed over thirty publications in peer-referred ISI journals.

Email: charlesokpala@gmail.com

Ivan Bartolo

Sea Fish Industry Authority, Europarc, Grimsby DN37 9TZ

Ivan is a Regulatory Affairs Advisor with the Sea Fish Industry Authority, UK. He holds degrees in Pharmaceutical Technology,

Food Technology and Applied Toxicology, and has held various food science roles in industry and government. Ivan is President of the Seafood Importers and Processors Alliance (SIPA). He held the post of Chair of the IFST Scientific Committee from 2011 to 2013, where he continues to serve as a member and is a Fellow of IFST and Registered Scientist (RSci).

Email: ivan.bartolo@seafish.co.uk

Web: seafish.org

Conflict of Interest: Charles Okpala declares there is no conflict of interest associated with this work. Ivan Bartolo is an employee of the Sea Fish Industry Authority, a UK non-departmental public body that has as one of its goals the promotion of seafood consumption.

References

1. F.A.O. (2016). The State of World Fisheries and Aquaculture 2016. Contributing to food security and nutrition for all. Available from: http://www.fao.org/fishery/sofia/en (accessed on 14 April 2018)

2. Olsen, S.O. (2004). Antecedents of seafood consumption behavior: an overview. Journal of Aquatic Food Technology 13(3), 79–91

3. Musarskaya, M., Birch, D. and Memery, J. (2017). To Eat or Not to Eat: Seafood Consumption Habit Formation. Journal of International Food & Agribusiness Marketing 30(3), 227-235.

4. Olsen, S.O. (2003). Understanding the relationship between age and seafood consumption: the mediating role of attitude, health involvement and convenience. Food Quality and Preference 14(3), 199–209.

5. Leek, S., Maddock, S., and Foxall, G. (2000). Situational determinants of fish consumption. British Food Journal 102(1), 18–39.

6. EUMOFA (European Market Observatory for Fisheries and Aquaculture Products) (2017). EU consumer habits regarding fishery and aquaculture products. Final report. Available from http://www.eumofa.eu/documents/20178/84590/EU+consumer+habits_final+report+.pdf (accessed 14 April 2018)

7. Farhankhan, P.I., Edible Fish Products. Available from https://www.slideshare.net/PathanFarhan/edible-fish-product-paper-11. Accessed on 03April 2018.

8. Mozaffarian, D. and Rimm, E.B. (2006). Fish intake, contaminants, and human health. Evaluating the risks and benefits. Journal of the American Medical Association (JAMA) 296(15), 1885–1899.

9. Okpala, C.O.R., Sardo, G., Vitale, S., Bono, G., and Arukwe, A. (2017). Hazardous properties and toxicological update of mercury: From fish food to human health safety perspective. Critical Reviews in Food Science and Nutrition. (in-press) Doi: 10.1080/10408398.2017.1291491 (accessed on 14 April 2018).

 



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