Study Shows High-Iron Beans Improve Women’s Physical Performance


by HarvestPlus | March 4, 2020

This post originally appeared on the HarvestPlus website. HarvestPlus leads A4NH work on biofortification.

In a study with potential significance for global nutrition strategies, iron-deficient women in Rwanda who consumed high-iron “biofortified” beans experienced not only improved iron status but also improved ability to conduct everyday physical tasks.

The study, recently published in the Journal of Nutrition, is the first piece of research to show that a solely food-based nutrition intervention (as opposed to taking supplements) produced an improvement in subjects’ “work efficiency”—that is, the amount of energy needed to perform light-to-moderate physical work such as walking, cleaning and other household chores.

Iron deficiency is the most common type of micronutrient deficiency; it is the leading cause of anemia and is known to cause fatigue and impair physical performance—such as a person's degree of physical endurance and work efficiency. In sub-Saharan Africa, 37 percent of women are anemic and nearly one in three cases are caused by iron deficiency.

Iron-biofortified beans, currently available in 14 countries, are developed through conventional plant breeding to contain up to twice the amount of iron as other common bean varieties. When eaten twice daily, these beans can provide up to 80 percent of daily iron needs.

Learn how iron beans gained ground in Rwanda

The Rwanda study included 125 female college students ages 18 to 26 who had depleted iron stores but were otherwise healthy; the subjects were randomly assigned to either a group that received iron-biofortified beans or one that received non-biofortified beans.

The women in both groups received two meals a day over the following 18 weeks. Those who ate iron-biofortified beans, and whose hemoglobin (a measure of anemia) or iron status improved, exhibited a significant reduction in the energy needed to perform light physical work.

“This is the first study to show an effect of a food-based intervention on moderate levels of physical work capacity,” said Jere D. Haas, Emeritus Professor of Nutrition, Cornell University, and senior author of the study. He noted that previous studies involving iron supplements had shown that improving iron status in iron-deficient adults can improve their ability to perform heavy work.

“This [latest] study compliments our previous research in Rwanda that showed that consumption of iron-biofortified beans resulting in improved iron status, also improved cognitive and brain function in the same adult women,” Haas added.

“Common beans are an important source of multiple nutrients and health-promoting phytochemicals in several low- and middle-income countries where iron deficiency remains a public health problem,” said Erick Boy, Head of Nutrition at HarvestPlus. “This study confirms that not only can biofortified beans effectively build up young women’s iron stores to ensure healthy future pregnancies, but also that regular consumption can help women derive greater productivity from paid physical work (e.g., in agriculture), and they will not get physically fatigued as easily.”

HarvestPlus, in collaboration with multiple partners, promotes high-iron beans and several other biofortified staple crops in countries worldwide. By the end of 2018, 1 in 5 bean growers in Rwanda grew these naturally nutritious beans, which are also high yielding, disease resistant, and heat and drought tolerant. Biofortified crops deliver nutrition to smallholder farming families and others who are at high risk of micronutrient deficiencies and are not easily reached by  fortification and supplementation initiatives.

Special Note: HarvestPlus would like to acknowledge Sarah V. Luna, the principal author on this study, who passed away tragically on May 20, 2019. She diligently contributed to the laboratory and field work, data analysis, and the initial draft of the article. This posthumous publication is an homage to her lifelong commitment to excellence in academia and service to others. 


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