As people around the world generally gain access to more food, their diets also are becoming more similar. And scientists express concern that a decline in dietary diversity could lead to increasing health problems. A report on the study, titled “Increasing homogeneity in global food supplies and the implications for food security,” is published in the journal Proceedings of the National Academy of Sciences.

The authors note that crops such as wheat, rice, corn, potatoes and soybeans have increasingly become the standards within the global food supply. Wheat is a major staple in 97 percent of countries and rice in 91 percent, while soybeans are gaining as a global staple food, as a significant portion of diets in 74 percent of countries.

Adoption of these crops, in many cases, comes at the expense of local or regional foods that historically played important nutritional roles for people around the world. The authors note that crops such as sorghum, millets, rye, sweet potato, cassava, yam and others have become less prominent in global diets.

Quoted in a news release, lead author Colin Khoury, a scientist at the Colombia-based International Center for Tropical Agriculture (CIAT), says "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. 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."

The researchers also express concern that increasing homogeneity in food production could make agriculture more vulnerable to threats such as drought, insect pests and diseases, which could be exacerbated by climate change.

Several factors have led to adoption of more Western-style diets around the world, according to the report. These include urbanization, trade liberalization, mechanized agriculture, extensive commodity transport systems, multinational food industries, food quality and safety standardization, mass media, labor changes, smaller family sizes, supermarkets, fast food, processed foods and human migration.

The research abstract and full article are available online from the Proceedings of the National Academy of Sciences.