Wednesday, 14 December 2011

Genetically Modified Foods: Unanswered Questions

Genetic modification (GM) is a process commonly discussed but rarely defined. Without a clear definition of GM, how can we critically assess the benefits and costs of GM for human health and the health of the planet? At the very least, GM technology has increased our vocabulary. Nowadays, Transgenic, Genetic Engineering, Recombinant DNA, and Biotechnology are widely used in agricultural and political discourse. But, has this new lexicon led to a better understanding of how, why, and for whose benefit are we modifying our foods?

Starting with its most general definition, GM means altering an organism’s genetic make-up. GM is often synonymous with genetic engineering - a process whereby genes from one life form are transferred into the genes of another life form (a.k.a Recombinant DNA technology). If we understand GM as genetic engineering, the first commercially grown GM crop was tobacco. GM tobacco contained genes from other plants that were resistant to the common tobacco virus. GM crops were also created to prevent rotting. The “Flavr Savr” GM tomato was created in the 90’s to slow the ripening process to prevent it from pre-mature softening.

GM technology was revolutionized in the late 90’s. The creation of herbicide and insect resistant plants was made possible by inserting genes from other organisms into food crops. You may have heard of examples of these GM plants such as Bt Cotton and HT Alfalfa. Bt refers to the bacterium, Bacillus thuringiensis and a Bt crop contains a gene taken from this bacterium that confers insect resistance. HT means “herbicide tolerant” and an HT crop means it contains a gene that gives it immunity to a chemical weed killer. HT crops can survive spraying with weed killing chemicals, and thus HT crops are ideally used to maximize agricultural output. 

What distinguishes GM through engineering from human’s long history of domesticating plants?

Some have argued that GM through engineering is a continuum of the natural processes of plant modification in human history. This makes sense if we remember that indigenous peoples’ sustained efforts to cultivate multiple varieties of forest plants have resulted in the domestication of numerous foods we continue to eat. But, can we now equate the processes of domestication, trade, and exchange of wild plant varieties with the engineering of life forms by moving certain desirable genes into plants? 

Plant modification is part of human existence on earth. But, it is hard to assess the social and ecological impacts of gene-modification without an understanding of the bigger picture. Why are we manipulating plants? Who is doing the manipulation? What sectors of society benefit from the GM technology? Who are these new technologies excluding? Presently, we know that most GM crops being used have been modified to maximize agricultural profits. Very few initiatives to increase nutritional content of plants through genetic modification have reached marginalized peoples. To my knowledge, Golden Rice – a plant engineered to aid vitamin A production (critical for vision) and to be used where people are vitamin A deficient - was proposed in 2000 but has not yet reached the market.

Also, we know very little about how the successes of GM initiatives have been measured? For example, when the use GM crops are reported to have increased farmer’s yields, what are we comparing these numbers to? Are we improving crop yields compared to industrial monoculture or compared to long-standing traditions of organic and agro-ecological farming methods? Before we uncritically accept the widespread use of GM crops, these questions need to be addressed.

Different approaches to GM crops by country:


Stone, G. D. (2010). The Anthropology of Genetically Modified Crops Annu. Rev. Anthropol. , 39 (1), 381-400 : 10.1146/annurev.anthro.012809.105058

Tuesday, 6 December 2011

Tropical Forest Foods: Sharing Manioc’s Story

Manioc Plant (

Sharing food is sharing a story. No matter where in the world I find myself, every food has its own tale to tell. Food stories often involve where and with whom we shared the ‘best’ meal. But, many stories about food remain untold. This weekend, in preparation for a farewell dinner before I head off to Costa Rica, I uncovered manioc’s food story.

Manioc Roots (

The edible part of the manioc plant we find in supermarkets (Manihot esculenta) is a large root. Similar to the sweet potato, this is a storage root also called a tuber. The roots of manioc are harvested from plants 1- 5 meters tall; these shrubs belong to the Euphorbiaceae family of plants. In the tropics, manioc plants are typically found in people’s gardens and cultivated for small-scale use. 

Manioc (also known as cassava, yuca, or mandioca), may not be well known in Canada or the United States, but it is a dietary staple for people living in the tropics. In fact, next to wheat and rice, manioc contributes more to the diet of people living in the tropics than any other food.

Indigenous people have practiced manioc cultivation for millennia. The manioc domestication process began in South America somewhere between 5,000 and 10,000 years ago. Much later, around 400 years ago, manioc was introduced into West Africa.
Edible Manioc Roots 

There are many different manioc varieties and indigenous peoples in Latin America may manage the cultivation of 100 or more varieties at a time (here in North America we likely only see one of these varieties). Some varieties of manioc are bitter and some are sweet. The bitter varieties are toxic for human consumption if eaten raw because they contain cyanide. Indigenous peoples have devised various systems to detoxify these bitter varieties of manioc. One such system involves the roots (tubers) being peeled, grated (like you would grate cheese), and the pulp placed into cylinder shaped containers. These cylinder containers are hung with a heavy weight attached to the base. The weight attached to the containers serves to compress the manioc pulp and expel any toxic juices. Once the toxic juice is removed, the manioc pulp can be washed and roasted, and prepared in many different dishes. In Brazil, for example, manioc pulp is made into flour (farinha) and used to make bread or tapioca. In Ghana, manioc is made into a paste (fufu) and served with many dishes, much like rice elsewhere. In many countries manioc is also fermented and used to make beer.

One of the reason’s manioc is an attractive food source is that it is easy to grow. It tolerates drought and infertile soils, recovers quickly from pest damage, and can be planted at any time of the year. While living in Costa Rica, I was always surprised with manioc’s heartiness when I found manioc plants in unexpected places, such as abandoned fields or roadsides.

Although manioc is high in calories, it is low in protein, vitamins A and E, iron and zinc. Considering manioc’s role in meeting the needs of many people, it may not be a surprise for me to tell you that research is underway to modify the nutritional content of these plants. This research is funded by the Bill & Melinda Gates Foundation and Monsanto, and is an attempt to genetically engineered manioc varieties that are relatively high in iron and zinc.

Monsanto’s support was not provided without certain conditions. This corporation reserved the right to charge farmers for the use of these improved varieties if their income exceeds $10,000 a year.

Nutritional improvement, such as genetic engineering, is one way to address hunger, nutrition, and food security. Another is to work with people to understand some of the root causes of malnutrition, poverty, and food ‘insecurity’. As outsiders, often our perspectives of these problems are different from those of the people eating and growing plants. In planning my research, I received some wise guiding words from my Bribri (an indigenous group) colleague in Costa Rica. He expressed to me, in reference to studying how people use plants, how important it was to talk to people that use plants before making assumptions regarding what is needed to improve people’s lives. All too often, outsiders go into research with preconceived notions that indigenous people are poor and malnourished. In the case of many Bribri people, my colleague expressed this was not the case. Rather, tropical forests provide them with ample nutritious foods. More pertinent problems for the Bribri concern their rights to access plant resources in the face of rapid changes in land-use planning and property rights (e.g., intellectual property rights). This is a grave reminder that support for genetic engineering on rural people’s crops should not be granted without the guarantee that access and rights to these resources will not be lost in the process.

For those interested in trying manioc, it can be used as an alternative to potatoes or grain. In fact, 80 % of manioc’s total dry weight is edible (compared to only 35% for grain). And, even though manioc is highly perishable if left unprocessed, manioc products, such as flour and breads, can be stored a year or more. If you want to try manioc but don’t have an idea of how to prepare it, I suggest you start with fried manioc. Here is my Costa Rican recipe for yuca frita with chimichurri salsa.

Fried Manioc Recipe (serves 4):

1 – 2 manioc roots
butter and/or oil


Using a sharp knife, cut the manioc roots in half or in three parts. Peel the waxy thick brown skin off and rinse the white inside of the root. Chop this white root into rectangle-sized pieces, a little thicker than the size of carrot or celery sticks. I boil these sticks until you can stab them easily with a fork. Drain and set aside. Heat a pan of oil at medium heat and fry the boiled manioc sticks until golden brown. If you wish to use butter add this near the beginning of the frying process. Eat the fried manioc with chimichurri or dip these manioc fries into any of your favorite salsas.

Chimichurri (Salsa):

1 tomato
1 white onion
1 cucumber
1 juicy lime


Dice tomato, onion, and cucumber. Add a handful of cilantro and the juice of one lime. Add salt and pepper to taste. 

Nassar, N., & Ortiz, R. (2010). Breeding Cassava to Feed the Poor Scientific American, 302 (5), 78-84 DOI: 10.1038/scientificamerican0510-78

Heckler, S., & Zent, S. (2008). Piaroa Manioc Varietals: Hyperdiversity or Social Currency? Human Ecology, 36 (5), 679-697 DOI: 10.1007/s10745-008-9193-2