This week, scientists from the UK have published a study describing how they genetically engineered a purple tomato enriched with antioxidants that could provide potent health benefits (see the links for a picture). This reminded me instantly of a paper I wrote back in college for a Science and Politics class about the irresponsibility of the Greenpeace campaign against genetically modified food. In my research, I came across a picture from their campaign of a fetus growing in a tomato (hint: this is completely ignorant and inflammatory). Since that was some time ago, I was worried I might not be able to find it to share with you, but luckily, Google remembers all things. So genetically modified foods – friend or foe? Or perhaps we could start with a little game called genetically modified food… fact or fiction?
Question 1: Genetically modified tomatoes have genes, while normal tomatoes do not. True or false?
FALSE! As we’ve discussed earlier in a post about model organisms, ALL living things have genes encoded in their DNA. Some of you might scoff at this question, but according to a 2004 study by the Food Policy Institute, nearly 1/4 of Americans thought normal tomatoes didn’t have genes (see links below for a PDF of the report).
Question 2: A tomato genetically modified with a catfish gene would probably taste fishy. True or false?
Again, false, though the study showed that more than 1/4 of Americans believed it was true. In fact, tomatoes and catfish actually already share some of the same genes, as do most living things, because fundamentally we need to do many of the same processes. And scientists don’t transfer just any genes – they look for ones that specifically convey one trait that they are interested in. In the case of the tomato study, which we’ll get to in a minute, they transferred two specific genes from snapdragons that helped to produce extra antioxidants.
Question 3: Genetic modification of our food source is a very recent technology.
Also false! Farmers have been using genetic modification since the beginning of time in the form of selective breeding. If one cow has a trait that you like, you’d want to mate that cow as many times as possible to try to produce lots of offspring with the trait. On the other hand, if another cow has an undesirable property, you might not want to mate it at all. The end result is the same – you are selecting for a gene or set of genes that is desirable – it’s just that you’re doing it within a species.
Okay, let’s get back to these purple antioxidant tomatoes. Why bother to mess around with this?
Well, antioxidants have a lot of health benefits. They are able to produce an antioxidant called anthocyanin in these tomatoes, and it has been shown to provide a variety of health benefits, such as protection against certain degenerative diseases, cancers and other aging-related risks.
In order to get enough anthocyanins and other antioxidants in our diets, we need to eat at least 5 servings of fruits and vegetables per day, but studies show that less than 25% of Americans eat enough. There are many social and economic reasons for this, and scientists hope to enrich these types of compounds in some fruits and vegetables, in order to make it easier for people to reach this goal.
So how did they make the tomatoes produce more antioxidants?
Scientists knew that tomatoes had a gene that produced anthocyanins in the skin of the tomato, so they wanted to see if they could turn it on in the meat of the tomato also, in order to increase the overall levels in the fruit (yes, tomatoes are a fruit).
They knew that there were two genes in snapdragon plants that were responsible for turning on the gene that produces anthocyanins, so they decided to transfer the genes into a commercial strain of tomatoes.
And it turned on the gene?
Yep. They were able to show that these tomatoes produced three times as many anthocyanins. Not only that, but they fed them to a strain of mice that was prone to developing cancer and found that they increased the average lifespan from 146 to 182 days. That may not seem like a lot, but it’s a ~25% increase – that equates to someone who would have died of cancer at, say, age 60 actually living to be around 75 years old.
Could they help people who are prone to cancers, too?
Maybe. The mice were given these tomatoes as 10% of their total diet, which is a whole lot, especially when you look at people, who are a lot larger. So it’s unclear how much of a benefit they would provide to humans in the context of a normal, balanced diet, but it’s true that some antioxidants are better than none.
So when can I pick these up at my local grocery store?
No time soon! These tomatoes would have to go through vigorous testing in order to prove that they’re safe for humans to eat. Introducing the genes that increase anthocyanin production could also have unintended side effects. The types of studies necessary to get approval are time-consuming and expensive, so they would likely only happen if a company showed interest.
Genetically modified tomatoes (and food, for that matter)… good or bad?
Tough question. It’s probably too early to know. Proponents argue that it allows us to tackle the problem of world hunger by adding nutritional and environmental benefits like antioxidants and protective pesticides respectively. Opponents argue that tampering with Mother Nature could lead to unintended consequences, causing environmental and public health problems. Reality is probably somewhere in the middle. The important thing is that we approach these problems scientifically and take great pains to understand exactly what we’re doing to these organisms, and as a result, the environment and ourselves. The good news is that there are a lot of regulations in place to make sure that the science is responsible, while still allowing room for innovation. Of course it is important to have a good understanding of any potential consequences, but when conducted responsibly, this type of research has the potential to do a lot of good for a lot of people.
THE BOTTOM LINE
Scientists have found a way to use genetic modification to enrich tomatoes in antioxidants, which could provide us with numerous health benefits. You won’t be seeing these in stores any time soon, though, because there’s a lot of testing that would need to be done first to make sure they’re safe for human consumption.
Food Policy Institute Report – A summary of national surveys conducted by the Institute on attitudes towards genetically modified food.
5 A Day Website – See statistics about fruit and vegetable consumption from your area
Pictures of the purple tomatoes – A media release from the John Innes Centre in the UK, where the study was conducted
Washington Post Article – On the study and why we won’t be seeing purple tomatoes in the grocery stores any time soon
PubMed Abstract – Describing the original study
Image borrowed from Greenpeace