Omega-3 fatty acids, particularly the long chain ones [Eicosapentaenoic (EPA) and Docosahexaenoic acid (DHA)] that are usually found only in fish oil, have a well recognised role in reducing the risk of cardiovascular disease. The recommended minimum intake of these fatty acids is 450 mg/d, but current estimates of actual intakes are only about 200mg/day.
Actual intakes are in fact even lower, as the major source of these fatty acids is oily fish and 73% of the adult population never consume any oily fish. It has been estimated that actual intakes for most of the population is closer to 100mg/day.
Two criteria must be met must be met if manipulating a food is to have a successful effect on population intakes of a particular nutrient. First, the food must be consumed in sufficient quantities that enriching it will have an impact on the consumption of the particular nutrient. Second, the food must be amenable to manipulation, so that the concentration of the nutrient can be increased to a meaningful amount.
In the case of EPA and DHA in chicken meat, both criteria are met. Chicken meat is widely consumed throughout the EU (and particularly in the UK), and the concentration of EPA+DHA in chicken can be readily increased by changes in the broiler diet. The next question is how can you increase EPA+DHA concentrations in chicken? Quite simply by increasing the amount of EPA and DHA that the bird consumes.
Sources of EPA+DHA are fish oils and marine algal biomass and oil. In principle, this could be the source of the future if industrial production of algae that synthesise EPA or DHA could be increased sufficiently.
In trials at Reading University, feeding broilers a diet containing 40g/kg fish oil produces meat containing approximately 300mg EPA+DHA in a 200g serving (of uncooked meat). The EPA and DHA are not lost during cooking.
However, there is a potential issue with taint in the meat because of the fish oil. Vitamin E (included at 100iu/kg diet to meet the bird’s requirements) protects the meat and sensory analysis by taste panels has not detected any difference between this “enriched” meat and “control” meat when the meat is freshly cooked.
However, “warmed over flavour” does develop in the “enriched” meat, such that cooked, refrigerated and reheated meat can have a fishy taste. Higher inclusion rates of vitamin E will probably overcome this problem, but this will be tested in future work.
It is difficult to assess how great an impact a single change in diet might have on the nation’s health. However, estimates from an analysis of the relationship between fish intake and the reduction in the risk of death from coronary heart disease suggest that, if all “conventional” chicken was substituted with “enriched” chicken, then at current levels of chicken consumption in the UK, over 2000 lives would be saved every year in England alone.
So how could the producer benefit from this? The production of nutritionally enhanced meats provides an opportunity for producers to produce a niche product at a premium price. The identification of alternative sources of EPA and DHA will reduce the producers’ reliance on fish oil and help make this approach more economically attractive.
• Dr Caroline Rymer has been a senior research fellow in the University of Reading’s School of Agriculture, Policy and Development since 2002, working on various aspects of animal nutrition in relation to human health.