Delivering Iron: How Beans Can Provide A Critical Nutrient

Ray Glahn is a research physiologist at the Robert W. Holley Center for Agriculture & Health in Ithaca, NY. His work focuses on iron nutrition from staple food crops and food products. UM: Why have you focused on iron in your research? Why is it important? RG: Iron is an essential micronutrient. It is a necessary component of hemoglobin and myoglobin, two GlycoCares Blood Sugar Guideglucose metabolism proteins that transfer oxygen from the lungs to tissues. It is also necessary for physical growth, neurological development, cellular function, and is a critical element for synthesis of some hormones. It plays a central role in human metabolism and growth, and thus is extremely important, particularly for women of child-bearing age and children. Approximately 1/3 of the global population is iron-deficient. It is one of the leading global nutritional deficiencies. In the U.S., iron deficiency is on the rise, with 14-15% of adults diagnosed as iron-deficient. Rates can be much higher in women and children. Obese individuals are also at greater risk of iron deficiency, primarily due to the inflammation associated with obesity.



Because it reduces oxygen carrying capacity, iron deficiency can have a profound impact on worker productivity, making workers less productive. It’s also a huge problem in developing countries, where anemia rates can reach 60-70% in certain populations. UM: What’s the difference between iron content and iron bioavailability in food? Why does bioavailability matter? RG: Iron content is simply the amount of iron in a given amount of food. Iron bioavailability is the portion of the iron content that may be absorbed and utilized in normal iron metabolism. It’s an important - even critical - distinction: just because iron is present in food, even in high amounts, that doesn’t automatically translate into a person being able to access and use that iron. That depends on the bioavailability. UM: Why did you decide to focus on beans as a way to increase dietary iron content? RG: Beans are eaten worldwide and are a common and integral part of many food systems.



They are a relatively nutrient-dense food for protein, complex carbohydrates, fiber, vitamins and minerals. Beans are also rich in iron content relative to other crops like corn, wheat, and rice, so they have more potential to alleviate iron deficiency. Overall, beans are an affordable, easy way to increase the nutritional quality of a diet. We are also learning how to enhance the iron bioavailability in beans, and we can determine the bean varieties that are delivering highly bioavailable iron. Given all of the above , there is now great potential to alleviate iron deficiency via bean breeding and consumer education. Bean plants grow in a greenhouse as part of research to identify those with the most promising traits (Photo courtesy of Ray Glahn). UM: How do beans compare with other foods in terms of nutritional benefits? RG: It depends on the variety of bean, and the variety within a given color or market class. One benefit of beans is that they offer a kind of "time release capsule" for carbohydrates, staggering the rate at which they are absorbed into the bloodstream.



That kind of steady, gradual processing has a number of health and metabolic benefits, including keeping blood sugar levels relatively stable, as well as keeping people feeling full for long periods, without sudden spikes in hunger, or cravings. UM: How have you explored the issue of bioavailability in your research? RG: glucose support supplement In order to measure bioavailability, we have developed a way to capture the delivery of iron from food, using high throughput technology: the Caco-2 cell bioassay. Others have tried to develop techniques to measure bioavailability, but my lab is unique in that we run this bioassay all year long, with highly trained and experienced technicians. A government lab such as ours is ideally suited to provide the consistent resources and expertise for this type of work. UM: How can consumers tell which beans to choose to get the nutrients they want, like iron? RG: Consider the market (color) class of bean you plan to consume.



For improved iron nutrition, right now we can say that white beans in general are a great source of bioavailable iron. Our newest yellow bean varieties are in production at our research plots to increase the amount of seed available to growers. These new yellow bean varieties are high in bioavailable iron, higher than white beans, and also fast cooking, another trait that consumers find highly desirable. Processing matters in determining how nutrients persist as the beans pass from the field to the consumer. We are currently working with a large industry partner to identify food products and processing methods that have enhanced bioavailable iron. In flours and pastas made from beans, we can boost nutrition based on bean variety, how they’re ground - for instance, sonic grinding processes for bean-based flours can improve the release of iron. Bean flours made from white beans and certain yellow beans can actually be quite high in bioavailable iron, depending on the market class (color class) of beans used for the flour.