Iron content in different types of beans
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Iron Content in Different Types of Beans
Iron Content in Fava Beans, Common Beans, and Tepary Beans
Fava beans show a wide range of iron content, from 1.8 to 21.3 mg per 100 grams on a dry weight basis, depending on the specific cultivar. However, only some cultivars provide iron in a form that is easily absorbed by the body, which is important for diets relying on legumes as a main iron source .
Common beans (Phaseolus vulgaris) also display significant variation in iron content. Studies of large collections of common bean varieties report iron concentrations ranging from 34 to 89 mg/kg (equivalent to 3.4 to 8.9 mg/100g), with an average around 5.5 mg/100g . Other research on landraces and commercial varieties found iron content between 58.7 and 144.2 µg/g (5.87 to 14.42 mg/100g) . Biofortified common beans, bred specifically for higher iron, can reach up to 7.3 mg/100g, but the difference compared to non-biofortified beans is often small and may not translate into higher iron absorption 257.
Tepary beans (Phaseolus acutifolius), especially white varieties, have iron content ranging from 29.8 to 78.47 µg/g (2.98 to 7.85 mg/100g). Pinto beans, by comparison, have lower iron concentrations, averaging about 3.36 mg/100g. White tepary beans not only have higher iron content but also better iron bioavailability than black or pinto beans .
Iron Content in Biofortified vs. Non-Biofortified Beans
Biofortified beans are developed to contain more iron, but studies show that the actual increase in iron content is often modest. In East Africa, both biofortified and non-biofortified beans had similar iron concentrations, averaging about 7.1 mg/100g, and there was no significant difference in iron bioavailability between them . Other studies confirm that while some biofortified varieties have higher iron than traditional types, the improvement in iron absorption is not always significant 457.
Factors Affecting Iron Bioavailability in Beans
The amount of iron in beans is not the only factor that matters; how much iron the body can absorb (bioavailability) is also important. Compounds like phytic acid and polyphenols, which are present in beans, can reduce iron absorption. For example, white tepary beans have lower levels of these inhibitors, resulting in higher iron bioavailability compared to other bean types 36. Similarly, common bean varieties with lower polyphenol content, such as white beans, tend to have better iron bioavailability .
Genetic and Environmental Influences on Iron Content
There is substantial genetic variability in iron content among different bean types and cultivars, which means that breeding programs can select for higher iron levels. However, environmental factors such as soil and climate also influence the final iron content in the beans. Some cultivars are more stable in their iron content across different environments, while others show more variation 8910.
Conclusion
Iron content in beans varies widely depending on the species, variety, and growing conditions. Fava beans, common beans, and tepary beans all offer significant amounts of iron, but the actual amount and its bioavailability depend on the specific type and cultivar. While biofortified beans can have higher iron content, the difference is often small, and factors like phytic acid and polyphenols can limit how much iron the body absorbs. Selecting bean varieties with both high iron content and good bioavailability is key for improving dietary iron intake from beans 12345678+2 MORE.
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