LONDON — The United States, Denmark, Norway, France and The Netherlands are the five most food-secure countries in the world, according to the Global Food Security Index (G.F.S.I.) released July 10 by the Economist Intelligence Unit (E.I.U.).

The index, which was developed by the E.I.U. and sponsored by E.I. du Pont de Nemours and Co., examined the core issues of food affordability, availability and quality across 105 developed and developing countries. The categories were further subdivided into a series of indicators that evaluate programs, policies or practices that influence food security.

The top five countries achieved their rankings due to a combination of “ample food supplies, high incomes, low spending on food relative to other outlays, and significant investment in agricultural research and development,” the E.I.U. said.

“The rapid rise of emerging marketing has increased demand for food of all kinds, but investment and productivity of new supplies haven’t always kept up,” said Leo Abruzzese, director of global forecasting for the E.I.U. “Filling the gaps in national food security networks requires a more careful understanding of where the weaknesses are and how to address them.”

The United States was the highest ranking country, with a score of 89.5 out of a possible 100, followed by Denmark at 88.1 and Norway at 88. The lowest scoring country in the survey was the Democratic Republic of Congo, at 18.4.

According to the E.I.U., of the top 10 richest nations as measured by gross domestic product per capita, only Australia finished in the top 10 for micronutrient availability. The United States had a micronutrient rank of 15, while Denmark and The Netherlands were tied at No. 23.

“Nearly all high-income countries have ample levels of vitamin A in their diets, but they are significantly lacking in iron from vegetables and vegetable products,” the E.I.U. said. “Developing countries have higher iron availability from vegetal sources, which is all non-animal products.”

Protein quality also correlates well with overall food security, the E.I.U. said. The indicator was calculated by assessing the presence of nine essential amino acids in the average national diet. According to the E.I.U., three Mediterranean countries — Israel, Greece and Portugal — fared best on the protein quality indicator. Latin American countries also fared well, particularly upper middle income countries.

Poor diet diversification, meanwhile, often indicates a lack of sufficient nutrients, the study showed. The E.I.U. said the problem is most acute in South Asia. In Bangladesh, for example, rice makes up 60% of food consumption, and nearly 50% of children were moderately or severely underweight in 2005. In Nepal, also one of the lowest ranked in this category, consumption is diversified more broadly across wheat, rice and maize, yet carbohydrates still make up 74% of overall caloric intake.

“Research has shown that successful interventions among the rural poor include a combination of crop diversification, use of indigenous food plants and promoting nutritional awareness in schools,” the E.I.U. said. “Diet diversity presents a different set of issues in emerging and advanced economies. Residents of wealthy countries, and increasingly of emerging ones, consume large quantities of processed foods that do not fill most nutritional needs. That economic development leads to a ‘nutrition transition’ — a shift in consumption patterns, work and leisure habits that often results in high-fat and sugar-rich diets and less exercise — has been known for some time. In some regions, the problem is accelerating.”