Modifying nutritional value

Researchers are trying to improve the nutritional value of soy.

Some researchers are focusing on techniques to produce omega-3 fatty acids, other fatty acids and proteins in soy. Omega-3 fatty acids, which reduce cholesterol levels in the blood, are naturally found in leafy green vegetables, vegetable oils, and fish such as salmon and mackerel.

Increasing the levels of omega-3 polyunsaturated fatty acids in soy is desirable for both health and environmental reasons. They are important for prenatal and early childhood brain development. And, because these compounds are primarily found in coldwater fish, such as salmon, tuna, halibut and herring, the declining state of marine fisheries and levels of mercury contamination are a concern. GM soy plants that supply omega-3 polyunsaturated fatty acids would not only be beneficial for consumers, but could also ease the pressure on fish stocks.

High-protein soy is desirable in countries for both human and animal foods where alternative proteins are scarce. It is gaining further acceptance in many parts of the developing world.

As a start, the CSIROs Food Futures Flagship has developed plants that produce DHA, a healthy omega-3 oil component that is vital for human health and normally only available from fish sources.

Omega-3 oils are polyunsaturated fatty acids that are considered 'healthy oils'. Docosa-hexaenoic acid, or DHA, is a long-chain omega-3 fatty acid that is favoured for its health benefits. DHA is found in every cell membrane in the body and is vital for brain and eye development in infants. It is also now widely recognised for its ability to reduce coronary heart disease risk, type-2 diabetes, Alzheimers disease and asthma.

Most Australians consume only a tenth of the recommended amount of DHA. Many foods are now enriched with omega-3 oils from fish, but with declining natural fish stocks, and aquaculture's current reliance on fish-based feeds, additional sources of long-chain omega-3 oils are urgently needed.

CSIRO researchers have placed DHA-producing genes into a plant that successfully produced DHA in its own seeds. Although it will be some years before commercialisation, crop plants capable of producing useful levels of DHA in their own seeds would have many benefits.

DHA enriched crop plants could provide consumers with cheaper and more varied sources of DHA – particularly valuable to those with fish allergies or who, because of cost, availability or choice, don't have a high level of fish consumption in their diet.

Demand on natural fish stocks as a source of DHA would be less. Fish in aquaculture could be fed DHA enriched plants, rather than continuing to use other fish as a feed, improving the sustainability of aquaculture without compromising quality.

For more information: http://www.csiro.au/science/ps3u.html