A Biotech Fish Food Could One Day Improve Human Health

Plant biotechnology could one day help make healthy Mediterranean and Pacific diets even healthier for a greater number of people while at the same time helping to preserve ocean fisheries, according to a Purdue University researcher. An enhanced strain of canola with an improved polyunsaturated fat profile could be used to feed farm-raised fish — an important source of omega-3 fatty acids for people, explained Charles Santerre, an associate professor of foods and nutrition at Purdue University in Indiana. "It seems that not a month goes by when we don't have another study touting the benefits of these long-chain omega-3 fatty acids," Santerre told an audience at the Biotechnology Industry Organization's 2003 annual conference in Washington, D.C., in June. "Consumers are really gobbling them up." Polyunsaturated omega-3 fatty acids — one of many types of fats in our bodies that are used for energy and tissue development — are considered essential for the normal functioning of the body, particularly for the eyes and brain, and are believed to protect against heart disease 1 and cancer. 2 Many types of fish — a central component of the Mediterranean and Pacific diets — are rich in omega-3 fatty acids. Unfortunately, the same source that gives fish the healthful qualities — a diet of smaller fish — can also introduce traces of PCBs and mercury. For that reason, it's recommended by most experts that pregnant women and young children avoid eating certain fish (swordfish, shark, tilefish, king mackerel and tuna steaks), and some recommend avoiding more species even though these contaminants are at very low levels and pose minimal risks. (Santerre argues that the benefits of long chain omega-3 fatty acids in farmed and wild salmon and farmed rainbow trout far outweigh the risks from the chemical residues.) Replacing their fish-based fish diet with plant-based food that has been genetically enhanced to contain more omega-3 fatty acids could help reduce the concern that some people currently have about these contaminants, says Santerre. "High stearidonate canola, for instance, could be used to replace fish oil and fish meal in feed and thereby further reduce PCBs in farm fish so it would have a benefit for those populations — pregnant nursing women and young children — who need those long chain omega-3 fatty acids and would like to avoid contaminants that are in the environment," explained Santerre, adding that eating eight ounces of salmon or trout per week is recommended for pregnant and lactating women. Using plant biotechnology, Santerre explained that a strain of canola could be developed with higher levels of stearidonic acid, which fish can convert four times more efficiently to beneficial omega-3 long chain eicosapentaenoic (EPA) and docoshexaenoic (DHA) fatty acid than linolenic acid, which is typically abundant in conventional canola. Santerre, who has worked extensively with Indiana environment and health officials on fish consumption advisories for anglers, 3 acknowledged that development of such a plant-based fish food is "more of a concept now" and is at least five to 10 years from reality. But he added that the salmon industry has expressed interest in the idea. While some crops such as flax, canola and soybeans can also be a source of omega-3 fatty acids in the human diet, Santerre explained that fish are considered a better source because the healthful nutrients can be more readily used by the human body. Improving profile of oilseed crops Improving the fatty acid profile of plant-based crops has long been the aim of both conventional breeding and plant biotechnology. Canola, for example, was developed by Canadian researchers from rapeseed, which yielded oil that could contain up to 55 percent of toxic erucic acid. 4 Using conventional breeding, researchers were able to reduce those levels to a safe 2 percent, and today, canola oil is one of the most healthful oils on the market. 5 Similarly, using plant biotechnology, a University of Nebraska researcher recently announced that he has developed an improved soybean with more "good" monounsaturated fats, which are particularly desirable for cooking, and less polyunsaturated and "bad" saturated fats. While polyunsaturated fats are essential in our diet, they are easily degraded during heating. In the past, to remove polyunsaturated fats from cooking oil, scientists "hydrogenated" the fats and produced undesirable "trans" fats. Oil from these genetically enhanced soybeans is stable during cooking and will not require hydrogenation. Plant biotechnology is also being used to raise levels of important micronutrients —such as sterols and polyphenols — that are found in red wines and fruits and vegetables, and are believed to help prevent heart disease. And it is also helping researchers better understand exactly what genes can confer healthful or harmful qualities to different foods. Inuits and heart disease Scientists first became aware of the possible health benefits of fatty fish such as salmon, trout, tuna, mackerel and herring after noting that Inuit people of Arctic Canada and Greenland, who eat a lot of fish, have low rates of heart disease. 6 Then, between 1958 and 1964, pioneering University of Minnesota researcher Ancel Keys studied more than 12,000 men from seven countries to test his theory that dietary fat is linked to cholesterol and heart disease. He discovered that men from Greece and France, whose diets were low in bad saturated animal fats and higher in good monounsaturated and polyunsaturated fats, had dramatically lower levels of coronary heart disease than American and Finnish men. "If other nations can live without heart attacks. …Why can't we?" he once asked. Since Keys' landmark study, medical researchers and plant geneticists have been searching for the factors within foods such as vegetable oils and fish that trigger these significant health benefits. Recently, the importance of omega-3 fatty acids have been recognized by several different studies. 7 Essential fatty acids The omega-3 fatty acid, linolenic acid, is one of two types of good polyunsaturated fatty acids that are essential to the diet, meaning the human body cannot produce them as it can saturated and monounsaturated fatty acids. 8 Linolenic acid, which is commonly found in plants, can be use by the body to create long-chain omega-3 fatty acids, like EPA and DHA (that are found in fish). The omega-6 fatty acid, linoleic acid, is also an essential fatty acid and is found in oils made from corn, sunflowers and cotton. In addition to not eating enough of these essential omega-3 fatty acids, North Americans also tend to not eat the right balance of omega-3 and omega-6 fatty acids, according to report from Canada's National Centre for Agri-Food Research in Medicine in Winnipeg, Manitoba. 9 "Although an optimal intake of omega-6 and omega-3 polyunsaturated fatty acids has yet to be established, it is often recommended that omega-6 and omega-3 fatty acids be consumed in a ratio of approximately 4:1 to maximize health benefits," said the report. "Most people who consume a conventional North American diet acquire omega-6 and omega-3 fatty acids in a much higher ratio (10-20:1)." 10 That's just one of the reasons why there has been so much interest in using plant biotechnology — as well as conventional breeding — to improve the fatty acid profile of oilseeds by creating specialty trait crops. Indeed, within the next five years, up to half of the canola grown in Canada could be specialty trait varieties, according to a November/December 2002 article in the Canola Digest published by the Canola Council of Canada. 11 "There've been a lot of negative connotations with biotechnology but that's going to change when you see some of these health benefits," said Randall Weselake, a professor of biochemistry at the University of Lethbridge in Alberta, who has conducted extensive research on the fatty acid profiles of vegetable oils. "Source":[ http://www.whybiotech.com/index.asp?id=3845]

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