Omega-3 fatty acids in the human diet, especially long-chain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are well established and recognised as important factors in reducing risk of cardiovascular disease. Humans have very limited ability to synthesise EPA and DHA through body metabolism, so the 450 mg per day intake recommended by nutritional experts must come from the diet.
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Consumption of long-chain omega-3 fatty acids in the general European population is low. Those people with a good balanced diet may consume an estimated 250 mg per day, but overall actual intake is less than a quarter (around 100 mg/day) of the recommended amount, largely because main source of these specific fatty acids is oily fish that many people do not eat. Oily fish is the main human dietary source of omega 3 due to significant concentrations of EPA and DHA in fish muscle.
The number of Europeans eating significant quantities of oily fish is surprisingly low. For instance, only 27 percent of the adult population in the United Kingdom (UK) eats fish, oily or otherwise. Many clearly have a strong aversion to anything fishy and oily, and especially the baby boomers (born 1946 to 1964). As children, many were forced to consume cod-liver oil and other fish-sourced oils because they are a super-rich source of oil-soluble vitamins A and D.
Enhanced omega-3 fatty acid content
Need to rectify the shortfall in omega-3 intake is the basis of research carried out at University of Reading (UK). A team of scientists in the School of Agriculture is investigating the benefits accruing from increased consumption of chicken with enhanced omega-3 fatty acid content through adding fish oil to poultry feed. The research is part of Lipgene, an European Union (EU) Sixth Framework Programme conducted at 25 research centres across Europe and collectively called the Lipgene Consortium. The full title of the project is the “Diet, genomics and the metabolic syndrome: an integrated nutrition, agro-food, social and economic analysis." It runs from 2004 to 2009 and is co-ordinated from the University of Dublin in the Republic of Ireland.
Successful manipulation of food to boost a population's intake of a particular nutrient demands two criteria are met. First of all, the food must be eaten in sufficient amounts so that the enrichment (in this case Omega-3) will positively impact on intake of the particular nutrient. In addition, the food must be amenable to manipulation, thus allowing concentration of the nutrient to be increased to at least the threshold level.
For EPA and DHA in chicken meat, both criteria are satisfied, says the team at the University of Reading. Chicken meat is widely consumed throughout the EU and can be readily manipulated to enhance concentration of EPA and DHA by simply changing the composition of rations fed to broiler birds. The key sources of EPA and DHA are fish oils but also marine algal biomass and the droplets of oil contained within the algal cells. With world fish stocks increasingly under pressure, algal biomass, generated and grown within industrial production plants, could turn out to be the most important source of EPA and DHA for the future.
Trials conducted at The University of Reading showed that feeding broilers a diet containing 40g/kg (4 percent) fish oil produces birds yielding 1500 mg of EPA+DHA per 1 kg of uncooked skinless white chicken meat. Since neither EPA nor DHA is broken down during cooking, the same level is transmitted right through to the consumer plate, meaning some 300 mg is consumed per 200 g of chicken cooked as part of a meal.
Warmed over flavour
There is a potential issue for fish oil causing taint taste problems in the meat, but that is overcome by further manipulation of the birds' rations. Vitamin E, included at 100iu (international units) per kg feed to satisfy birds' requirements for tocopherols and tocotrienols (active principles of Vitamin E), also protects the meat from fish oil taint. Sensory analysis by taste test panels did not detect any difference in taste between fish oil/omega-3 enriched meat and control meat when freshly cooked meat is used.
However, the team reports how a "warmed over flavour" does develop in the enriched meat, which means that meat that is cooked, refrigerated, and then reheated can assume a fish-like taste. They believe higher inclusion rates of vitamin E will probably overcome this problem and they will test their hypothesis in future.
Benefits for healthy hearts, industry
Many factors combine to affect the overall level of cardiovascular disease in a particular population so it is difficult to generalise on the likely impact of this one particular change in human diet. Analysis of the relationship between fish intake and reduction in fatal coronary heart disease, using current chicken consumption levels for the UK, predicts 2,000 less deaths in England (population 50 million), if all conventionally fed chicken was substituted with omega-3 enriched chicken.
The benefits do not end there. Production of nutritionally enhanced chicken meat offers increasingly hard pressed poultry farmers the opportunity to produce a niche market product that can be sold at a premium price. It will no doubt benefit the birds' health as well, which is not to be sniffed at in markets like the UK where there is increasing focus on bird welfare as well as healthy eating.
