November 23, 2014

New Genes for Your Potatoes

by David Warmflash

Over the years, we’ve gone to great lengths to make fried potato foods healthier. Potato chip makers don’t fry them in animal shortening anymore, for example, and many companies have given up using vegetable shortening (made from partially hydrogenated vegetable oils) because of the trans fatty acids. In high-end food stores, chips and fries prepared with olive oil, canola oil, high omega-3 content, and reduced salt are big sellers. All of these efforts really do make fried potato foods better for the blood vessels in your heart and brain, the health of which is related directly to two of the main causes of death: heart disease and stroke. But none of this protects you from a chemical compound that builds up in potatoes due to heating: acrylamide.

Known for its utility as an industrial chemical building block, acrylamide is not something you want in your diet. Derived from the amino acid asparagine, which occurs naturally in various vegetables, particularly in common types of potatoes, acrylamide is toxic. Its levels start to build up when the asparagine-high foods are heated above 120˚ C. This can happen during baking or broiling, but more easily during frying, and thus studies have found fairly high acrylamide levels in potato chips, French fries, and similar products. While the United States Food and Drug Administration regulates levels of acrylamide allowed in materials that contact food, so far the levels of acrylamide in food itself are not regulated.

Laboratory studies on rodents suggest a possible causative association between acrylamide and cancer. As for how this translates to humans, scientists are particularly concerned about cancer of the oropharynx (mouth and throat), esophagus, colon, kidney, ovary, and breast, and human studies are now in progress. Searching for definitive evidence is fairly complex, due to confounding factors, particularly smoking. Thus, studies so far are fairly inconclusive regarding dietary acrylamide.

The prospect of a probable carcinogen produced by a crop that is so common in foods has prompted a company called Simplot to develop a potato engineered to produce dramatically lower levels of acrylamide than standard potatoes when heated to high temperature. Known as the “Innate Potato”, it was approved earlier this month by the US Department of Agriculture (USDA). Now, it’s being publicized as a “cancer-reducing” GMO potato that also resists bruising. In the wake of the initial excitement, one of Simplot’s largest buyers (McDonalds) sounded interested. More recently, however, the fast food chain decided against buying the new potato.

The prospect of lowering levels of a carcinogen in fried potato foods may eventually lead other big potato users to make the move that McDonalds has rejected. In the meantime, however, groups opposed to genetic engineering of food crops are mobilizing to fight the new Simplot potato. They are saying that calling this new genetically modified crop “anti-cancer” is premature. They’re right in the sense that since we don’t have clear evidence at this point that dietary acrylamide causes any human cancer. Even so, given the choice, latkes, fries, and chip lovers might prefer the much lower acrylamide levels that the genetically modified potatoes offer.

By selecting the most desirable varieties, and mixing seeds in different ways, humans have been modifying the food supply genetically for something like 12,000 years. The difference with genetic engineering is that technology enables selection, or control, of one specific gene at a time, and plants can be equipped with genes not just from other plants, but from virtually any other type of organism. To engineer the new potato, genetic engineers employed a technique called RNA interference. Rather than inserting genes from other organisms, small molecules called micro-RNAs were used by the potato scientists to modify the synthesis of proteins natural to the potato. This allowed for gene products with less asparagine.

Genetically modified organisms (GMOs) are found most commonly in corn and soy food products. Since corn and soy are used in so many processed foods, GMOs are consumed widely, but publically they are both criticized as promoted as a single category (i.e. GMO food vs. non-GMO food) rather than on a case-by-case basis (as they are evaluated by the USDA). The development of a particular GMO whose main selling point is that (at least hypothetically) it may reduce health issues may ultimately lead to a paradigm change in the public discourse involving GMO issues. While it’s unlikely that you’ll soon be seeing new high tech potato chips proudly displaying low acrylamide/high GMO credentials at your favorite health-food store, it is possible that the discussion from GMO opponents and proponents alike will become more nuanced in the years to come, as the features of particular genes and GMOs are emphasized.

In the meantime, Simplot is emphasizing the other main advantages of the new potato, namely the high resistance to bruising. Additionally, the Innate potato requires reduced amounts of water and pesticides to grow it compared with conventional potatoes, and leads to reduced carbon dioxide emissions. That reduced carbon footprint could be particularly attractive to those concerned not only about the health of individuals, but of our entire planetary environment.


David Warmflash

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David is an astrobiologist and science writer. He received his M.D. from Tel Aviv University Sackler School of Medicine, and has done post doctoral work at Brandeis University, the University of Pennsylvania, and the Johnson Space Center, where he was part of the NASA's first cohort of astrobiology training fellows. He has been involved in science outreach for more than a decade and since 2002 has collaborated with The Planetary Society on studying the effects of the space environment on small organisms.

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