For years advocates of agricultural biotechnology have promised a future in which foods will be genetically engineered to give more nutrition and prevent chronic diseases, in which crops will be modified to thrive in salty soil or hot or dry climates and in which consumers will benefit directly from science’s ability to tweak other characteristics of plants.
So far, however, that has generally not happened and the main beneficiaries of agricultural biotechnology remain farmers battling pests and weeds that threaten staple crops such as soyabeans, corn and cotton, as well as companies that develop and produce genetically modified seeds.
Consumers recently were reminded of what might be available in the future.
Researchers at the British-government-sponsored John Innes Centre announced they had developed a purple tomato that has high levels of beneficial anthocyanins — antioxidants known to neutralise potentially harmful oxygen molecules, or free radicals, in the body and reduce the risk of heart disease and cancer. The genes for the purple tomato came from snapdragons.
The creators of the purple tomato, a team led by Cathie Martin, tested their fruit in cancer-susceptible mice and found that the animals on a diet of 10 per cent powdered purple tomatoes in their pellets lived significantly longer than those eating powdered normal red tomatoes. Her findings were published in the journal Nature Biotechnology.
This advance does not mean that extra-healthful purple tomatoes will be on the market anytime soon — that would require much more testing in animals and humans and, perhaps a bigger hurdle, finding a company that wants to develop, market and sell them.
But Martin said the tomatoes are important because they are a promising example of a genetically modified food “that offers a potential benefit for all consumers”.
That is because the anthocyanins — which are also found in many berries and in red cabbage — would be delivered at high levels in a product that is widely and frequently consumed.
“The goal is to improve diets by putting important compounds such as anthocyanins in foods everyone eats,” Martin said.
Researchers are genetically modifying many other foods to make them more nutritious or to carry extra health benefits.
These include staples such as rice, cassava and bananas, and vegetable oils engineered to have higher levels of healthful omega-3 fatty acids.
Some are working on engineering ingredients in beer and white wine to boost levels of the antioxidant resveratrol, a heart-healthy compound found especially in red wine.
Unlike the explosion in biotechnology to protect crops from insects and weeds, these modified consumer products are in the relatively early stages of development, and there is seldom much money supporting their research.
What is more, they often require the introduction of two or more new genes into the existing plant or, as in the case of the purple tomato, the insertion of a “transcription factor” that controls the activity of numerous genes.
The health risks of this broader-brush genetic engineering have been far less studied than those that involve modifying or inserting a single gene.
Nonetheless advocates of food biotechnology say the promise is there. “The issue of food availability is becoming increasingly important and we know that genetically modified crops can help,” said Michael Wach, managing director for science and regulatory affairs at the Biotechnology Industry Organisation.
“With research into developing crops that can resist drought or poor soil, the importance of biotechnology to agriculture can only grow.”
Margaret Mellon, a food specialist with the Union of Concerned Scientists, disagrees. She generally views genetically modified crops as a problem.
Although biotechnology could help increase the yields of staple crops and make them more resistant to climatic stress, she said, foods modified for nutritional benefits have fared poorly.
“Biotech firms always used the promise of consumer-friendly, extra-healthy foods to fend off criticism of their pesticide- and herbicide-control products, which often were not terribly popular with the public,” she said.
“It doesn’t look exactly promising that we will get any of that kind of benefit anytime soon. Genetically engineering fruits and vegetables for nutritional benefits has proven more difficult than the industry expected.”
And even if vegetables and fruits can be genetically modified to contain an abundance of a beneficial compound, she asked, do we really want them?
Martin, the creator of the purple tomato, said conventionally grown fruits, vegetables and berries can supply the nutrients and minerals that people need.
But nutrition experts say that would require eating five servings a day, she said, and “eating one tomato instead certainly would be easier and more likely to happen”.
