Fish and fishery products play an important role in food and nutritional security around the world. Consumption offish offers unique nutritional and health benefits and is considered a key element in a healthy diet. Increased attention is given to fish as a source of essential nutrients in our diets, not only high value proteins, but more importantly also as a unique source of micronutrients and long chain omega-3 fatty acids.
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An irreplaceable source of long chain fatty acids
Foods from the aquatic environment have a particular role as a source of the long-chain omega-3 fatty acids, eicosapentaenoicacid (EPA) and docosahexaenoic acid (DHA). DHA is a major building block of our neural system, and therefore particularly important for optimal brain and neurodevelopment in children. Alternative sources of omega-3 fatty acids are found in many vegetable oils, but this is mainly alphalinolenic acid (ALA) that needs to be converted into DHA. However, in our bodies the conversion from ALA into EPA and DHA is in many cases inefficient, making it difficult to rely only on vegetable oil during the most critical periods of our lives, namely during pregnancy and the first two years of life (the 1,000 day window). A recent FAO/WHO expert consultation concluded that fish in the diet lowers the risk of women giving birth to children with suboptimal development of the brain and neural system compared with women not eating fish (FAO (2011). The State of World Fisheries and Aquaculture 2010, FAO Fisheries and Aquaculture Department. Rome, FAO. 218p. Available at http://www.fao.org/docrep/013/i1820e/i1820e.pdf)
Fish consumption is also known to have health benefits among the adult population. Strong evidence underlines how consumption of fish, and in particular oily fish, lowers the risk of Coronary Heart Disease (CHD) mortality; it is estimated that fish consumption reduces the risk of dying of coronary heart diseases by up to 36 percent due to the long-chain omega3 fatty acids found in fish and fishery products. CHDs are a global health problem affecting all populations. A daily intake of 250mg EPA+DHA per adult gives optimal protection against CHD (Mozaffarian, D., Rimm, E.B., 2006. Fish intake, contaminants, and human health: evaluating the risks and the benefits. JAMA, 296, 1885-99.). For optimal brain development in children the daily requirement is only 150 mg per day.
Aquaculture to meet increasing demand for fish
With a growing population worldwide, the demand for fisheries products will increase even if the per capita consumption remains at the present world average level of 19 kg/year (FAO, 2012).
It is believed that this increased demand will mainly be met from the increased output of aquaculture products, and not from wild sources.
At present close to 50 per cent of all fish for human consumption is farmed, a proportion which is set to rise making aquaculture the main source of essential nutrients provided by the fisheries sector. Even though the nutritional composition of farmed and wild fish in most cases is comparable, there might be some differences. From a nutritional point of view, the main difference between farmed fish and their wild counterparts is related to the quality and quantity of fat. The nutrient composition of farmed fish is frequently compared to that of wild fish, or to that of other farmed fish. How- ever, farmed fish should rather be compared to other farmed meats to show how aquaculture products have a marked nutritional advantage by providing high levels of essential nutrients, some of which are hardly found in non-aquatic foods.
The main farmed fish species, carps and tilapia, have much lower levels of the long-chain omega-3 fatty acids compared, for example, to salmon, but can still be considered good sources of these fatty acids. Compared to levels in beef or chicken, the levels in carp and tilapia are much higher (USDA, 2013). A single meal of carp can cover up to several days requirement of this essential nutrient. The role consumption of farmed carp plays for food and nutrition security is particularly evident in many Asian countries where the major part of this fish is consumed. Carpalone can cover the yearly need for long-chain omega-3 fatty acids of more than one billion people, significantly more than the contribution from all salmon species combined.
Wild and farmed fish are a healthy and better alternative to almost any other meats. Farmed fish have a more constant nutrient com-position compared to their wild counterpart, whose environment, food and access to food varies during the year. The environment of farmed fish can be monitored and managed to secure an optimal product. By controlling the composition of aquaculture feeds and other inputs, healthy fish and healthful fish products with the optimal nutritional composition can be supplied.
Better utilisation will also help meeting future demand
Improved utilisation of existing fishery resources should also play a more important role in meeting the increasing demand of valuable nutrients from the aquatic environment. Reducing post-harvest losses, estimated at more than 10 per cent in volume and up to 30 per cent in value, could release millions of tonnes of healthful fish products for consumption.
By-products as a result of processing represent in many cases more than 50 per cent of the fish being processed. These by-products are increasingly being used for fishmeal and fish oil production, replacing the small pelagics being processed into fishmeal and fish oil. This has prevented the volumes of small pelagics for human consumption from decreasing although capture of these fish has been diminishing for many years. Some by-products could also be used directly for human consumption. One example here is the increasing export offish heads from European and North American markets to Asian and African markets. These by-products are in many cases low cost products, but with a high nutritional value.
Small pelagics are cheap, nutritious, and filled with omega-3s
Fish is the main source of long chain omega-3s (EPA and DHA)in our diets. Increasing focus and knowledge on the beneficial properties of these fatty acids has increased the demand foromega-3 supplements. However, this might not be the most optimal way of utilising our fish resources. Taking supplements can result in intake of long chain omega-3s many times higher than the recommended daily intake, in some cases justified, but in most cases probably unnecessary. Several recent studies also suggest regular intake of omega-3 supplements has limited benefits compared to the benefits of regular fish consumption.
The availability of long chain omega-3s is limited and should be made accessible to as many people as possible. Consuming fish directly is an economical and efficient way of providing long chain omega-3s, and additionally providing many essential nutrients, in addition to EPA and DHA. Consuming one hundred grams of small pelagic fish such as sardines or anchovies once a week will more than cover the needs of omega-3s for a person. Small pelagic fish are among the most affordable and healthy fish. Two meals a week of most carps will do the same, and no fish oil is needed in their feed in order to become a good source of beneficial omega-3 oils. For some people supplements might be the only option, and fish oil supplements made from fish by-products, rather than whole fish, is a good example on how supplements can play an excel- lent role in giving more people access to the valuable long chain omega-3s.
August 2014
