4 March 2014

Massive decline in food crop diversity threatens global food security

by Will Parker

A detailed new study into global food supplies confirms for the first time what experts have long suspected: human diets around the world have grown ever more similar and the trend shows no signs of slowing, with major consequences for human nutrition and food supply reliability.

"More people are consuming more calories, protein and fat, and they rely increasingly on a short list of major food crops, like wheat, maize and soybean, along with meat and dairy products, for most of their food," said study lead author Colin Khoury, a scientist working within the Consultative Group on International Agricultural Research (CGIAR) Consortium. "These foods are critical for combating world hunger, but relying on a global diet of such limited diversity obligates us to bolster the nutritional quality of the major crops, as consumption of other nutritious grains and vegetables declines."

Appearing in the Proceedings of the National Academy of Sciences, the new research suggests that our growing reliance on a handful of food crops may also accelerate the worldwide rise in obesity, heart disease, and diabetes.

Khoury says that the crops now predominant in diets around the world include several that were already quite important a half-century ago - such as wheat, rice, maize and potato. But the emerging "standard global food supply" described in the study also consists of energy-dense foods that have risen to global fame more recently, like soybean, sunflower oil, and palm oil. Wheat is a major staple in 98 percent of countries and rice in 91 percent; soybean has become significant to 74 percent of countries.

In contrast, many crops of considerable regional importance - including cereals like sorghum, millets and rye, as well as root crops such as sweet potato, cassava and yam - have lost significant ground. Many other locally significant grain and vegetable crops have suffered the same fate. For example, a nutritious tuber crop known as Oca, once grown widely in the Andean highlands, has declined significantly in this region both in cultivation and consumption.

"Another danger of a more homogeneous global food basket is that it makes agriculture more vulnerable to major threats like drought, insect pests and diseases, which are likely to become worse in many parts of the world as a result of climate change," explained co-researcher Luigi Guarino. "As the global population rises and the pressure increases on our global food system, so does our dependence on the global crops and production systems that feed us. The price of failure of any of these crops will become very high."

As Khoury and Guarino examined current trends in food consumption, they documented a curious paradox: as the human diet has become less diverse at the global level over the last 50 years, many countries, particularly in Africa and Asia, have actually widened their menu of major staple crops, while changing to more globalized diets.

"In East and Southeast Asia, several major foods - like wheat and potato - have gained importance alongside longstanding staples, like rice," Khoury noted. "But this expansion of major staple foods has come at the expense of the many diverse minor foods that used to figure importantly in people's diets."

The dietary changes documented in the study are driven by powerful social and economic forces. Rising incomes in developing countries have enabled more consumers to include larger quantities of animal products, oils and sugars in their diets. Moreover, urbanization in these countries has encouraged greater consumption of processed and fast foods. Related developments, including trade liberalization, improved commodity transport, multinational food industries, and food safety standardization have further reinforced these trends.

"Countries experiencing rapid dietary change are also quickly seeing rises in the associated diseases of overabundance," says Khoury. "But hopeful trends are also apparent, as in Northern Europe, where evidence suggests that consumers are tending to buy more cereals and vegetables and less meat, oil and sugar."

The researchers single out five actions that are needed to foster diversity in food production and consumption and thus improve nutrition and food security:

The new study, relying on data from the Food and Agriculture Organization of the United Nations, encompassed more than 50 crops and over 150 countries (accounting for 98 percent of the world's population) for the period 1961-2009. "International agencies have hammered away in recent years with the message that agriculture must produce more food for over 9 billion people by 2050," said co-researcher Andy Jarvis. "Just as important is the message that we need a more diverse global food system. This is the best way, not only to combat hunger, malnutrition, and over-nutrition, but also to protect global food supplies."

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Source: Consultative Group on International Agricultural Research