Hippocrates said: “Let thy food be thy medicine and thy medicine thy food.”
“Functional foods” are the latest thing in the world of nutrition. These foods have benefits beyond supplying the bodies’ basic nutrients. Folic acid enriched bread, bacteria supplements to yogurt, vitamin D added to milk are all examples of functional foods. Although most people in the developed world have enough to eat, they do not always eat what is nutritious. Good nutrition is a cornerstone of preventative medicine.
Most of the first generation products of food biotechnology benefited the environment or the farmer. The second generation of crops is now beginning to reach the market. These products directly benefit the consumer. Biotechnology is engineering healthy additions to common food products.
Over 300 million metric tonnes of potatoes are grown annually, making it the fourth most important food crop in the world. At present there are four types of genetically engineered potatoes licensed for commercial use in Canada and the US. They all contain a protein called Bt, which protects the plant from insect attack. Unfortunately the major producers of potato products have succumbed to political pressure and do not accept these potatoes, even though Bt potatoes have shown dramatic reductions in organophosphate insecticide use. This action results in the continued use of large amounts of insecticides to control the Colorado potato beetle, a major pest of the potato crops.
Biotechnology research on potato species remains active in many countries. Some of the new varieties soon to reach the market include potatoes with increased protein content. By putting the seed albumin gene from Amaranthus into a potato, researchers have been able to increase the protein content from less than 1 percent to 14 percent. In many parts of the world where potatoes are a staple food, protein deficiency can be countered by this new nutritionally enhanced potato variety. Other researchers have engineered potatoes to possess higher starch content. These potatoes absorb less oil when fried. French fries, chips, and other fried potato products will contain less oil and, therefore, be healthier for human consumption.
Wild potatoes found in South America contain large amounts of toxic compounds called glycoalkaloids. Centuries of traditional breeding have reduced the levels of these anti-nutrients. Now researchers are developing potato varieties that have virtually none of these toxins. Similar research is being conducted on the tomato, a crop closely related to the potato. This type of engineering, called gene silencing, does not introduce new genes from other species but shuts down existing genes in a plant. An existing gene is inserted in the plant genome backwards. This results in the gene being shut down.
Using the same gene silencing technique, research is advancing in removing known allergens from food. It is estimated that 2 percent of adults and up to 8 percent of children are truly allergic to some type of food. The eight most common food allergies are: milk, eggs, peanuts, soybean, fish, crustaceans, tree nuts and wheat. A variety of rice has been produced with reduced allergenicity. The offending protein allergen in rice is only found in small amounts in the rice grain. This has allowed for the relatively simple construction of a hypoallergenic rice variety. This is not the case in something like peanuts. At least three different proteins are major allergens in peanuts and these proteins are found in high amounts. For these reasons, engineering a hypoallergenic peanut is unlikely for some time.
Researchers have taken a different approach to developing hypoallergenic wheat. Scientists have turned up the expression of a gene that will partially breakdown protein structures. The result is a variety of wheat that is less allergenic while maintaining the other characteristics prized in cooking and baking. Look for hypoallergenic wheat in the not too distant future.
Every year some 500,000 children go blind because of Vitamin A deficiency. Children in the developing world often die as a result of the loss of site. Researchers have created a variety of rice with elevated levels of beta-carotene, which is converted to Vitamin A in the human body. The rice with the gene for beta-carotene production has been crossed with local varieties of rice in the developing world. These new strains of rice are about to undergo field trials at the International Rice Research Institute (IRRI). If all goes well the new rice varieties will be given free to subsistence farmers in the developing world by 2006. The same beta-carotene production gene, originally isolated from the daffodil, has also been engineered into mustard. This will make mustard seed oil a good source of the vitamin A precursor. Together these two vitamin-enhanced crops could help stop blindness and death from vitamin A deficiency in the developing world.
Research into healthier tomatoes has reached an advanced stage. Lycopene is an antioxidant found in tomatoes and is thought to reduce the risk of several types of cancer and some forms of heart disease. Scientists have increased the level of lycopene 250 percent. The high lycopene tomato should reach the market within a few of years.
Other research using gene silencing has produced a delayed ripening tomato. This tomato can ripen on the vine longer, thereby increasing the healthy nutrients often missing when the tomato is picked while still green. Researchers are hoping to apply this delayed ripening trait to strawberries, melon, bananas, and bell peppers.
The health benefits of vitamin E are widely reported in medical journals. Vitamin E is only produced by plants and is essential in our diet. People in North America get most of their vitamin E from vegetable oils. But vegetable oils are low in the most beneficial form of vitamin E (alpha). Researchers have isolated the gene for an enzyme that converts the least effective form (gamma) of vitamin E to the most effective form (alpha). The level of alpha vitamin E was increased almost 10 times by engineering the enzyme into a test plant. Soy, corn, and canola all convert gamma to alpha in the same way. Hence, it is realistic to expect high vitamin E soy, corn and canola oil in the near future.
Ferritin is a protein that is responsible for the high iron content of beans.
Researchers have transferred the ferritin gene from the bean plant into wheat and rice to produce iron-enriched varieties. These new wheat and rice varieties are in field trials now. If successful, these new varieties could help reduce chronic anemia in many parts of the world.
Probably the most widespread health benefits engineered into food crops involve fat composition of soy and canola oils that are present in many processed foods and margarines. They are also widely used as cooking oils. There are several different types of engineered soy and canola oils, all developed for different purposes. Traditional soy and canola oil required modification by a process of hydrogenation in order for the oils to be most useful for cooking or as ingredients in processed foods. One of the by-products of hydrogenation is the production of trans-fats. Excessive trans-fats consumption has been associated with cardiovascular disease.
Traditional breeding by chemical mutagenesis has produced canola oil with high oleic acid content. Researchers have also engineered a soy variety with the same high oleic acid content. Because these oils do not require hydrogenation to make them suitable for cooking and food manufacturing, there is no trans-fat in either oil. There is also a soy variety that is high in a saturated fat called stearic acid. This fat is not associated with elevated cholesterol levels as most saturated fats are. Both soybean varieties were produced by shutting down (silencing) an existing gene. No foreign gene was introduced into these varieties. These healthy oils have been on the market for the past few years.
Canola is also high in omega-3 fats, the beneficial polyunsaturated fats found in fish such as salmon or tuna. Although the omega-3 fats in canola are not the same ones found in fish oils, they can be converted into the fish type fats in the human body. Research has shown healthy increases of some fish type fats when people consume canola oil. Research is ongoing into engineering the exact fish type omega-3 fats into canola. The genes that produce these healthy fats are found in the marine algae food of fish. This type of omega-3 enhanced canola is still a few years away.
The advent of Bt corn, with its built-in insect protection, has allowed farmers to reduce the amount of organophosphate insecticides by millions of pounds each year. An added bonus of this engineered insect resistance is a dramatic reduction in fungal toxins on the corn. Bt corn has up to 90 percent reductions in these nasty fungal toxins. Clearly this engineered crop is good for the environment and healthy for the consumer.
This article has dealt with some of the nutritional enhancements of food crops in the developed world. But it must be remembered that most nutritional problems in the developing world are a direct result of not enough food. Disease, rot, and poor yields, combined with ever increasing population are a larger problem for peoples of the developing world. The biotechnology sector of our economy is also hard at work trying to address some of these problems.
Robert Wager
Malaspina University College
Originally published in The Globe and Mail October 17, 2003