Greens with high iron
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High-Iron Green Leafy Vegetables: Nutritional Insights
Iron Content in Green Leafy Vegetables
Green leafy vegetables (GLVs) are recognized for their nutritional benefits, particularly their iron content. A study conducted in Muak Lek, Thailand, analyzed six popular GLVs: Holy basil, Sweet basil, Amaranthus spinosus, Lettuce, Chinese kale, and Coccinia. Among these, Coccinia pot liquor exhibited the highest iron concentration at 21.41 ppm, while cooked Lettuce had the lowest at 0.235 ppm. The study highlighted that consuming cooked GLVs along with their pot liquor maximizes iron intake .
Impact of Cooking Utensils on Iron Bioavailability
The method of cooking and the type of utensils used can significantly influence the iron content in GLVs. Research has shown that cooking GLVs in iron utensils increases both the total and bioavailable iron content. For instance, the total iron content in greens cooked in iron utensils ranged from 9.7 to 17.5 mg/100 g, compared to 3 to 13 mg/100 g in fresh greens. This increase is attributed to the leaching of iron from the utensils into the food .
Bioavailability of Iron in Different Vegetables
The bioavailability of iron from GLVs varies significantly. A study using an in vitro digestion/Caco-2 cell model found that Savoy cabbage had the highest bioavailable iron, likely due to the presence of low molecular weight fractions containing glucose, fructose, organic acids, and amino acids, which enhance iron absorption . Similarly, another study indicated that Moringa had the best iron bioaccessibility among several dark green leafy vegetables, attributed to its high levels of iron absorption enhancers like β-carotene and ascorbic acid .
Influence of Cooking Ingredients on Iron Bioavailability
In Cameroon, the addition of ingredients such as tomatoes, peanuts, melon seeds, and soybean seeds during the cooking of GLVs was found to affect iron bioavailability. For example, Vernonia amygdalina cooked with soybean had the highest iron content (128.28 mg/100g), while Amaranthus hybridus cooked with tomatoes showed the highest iron bioavailability (28.09%). The study concluded that the bioavailability of iron is positively correlated with vitamin C and negatively with phytates .
Nutritional Composition and Iron Bioaccessibility
The nutritional composition of GLVs, including their iron content, can be influenced by various factors. For instance, a study on collard greens demonstrated that increasing the iron concentration in the nutrient solution used for growing the plants enhanced the iron content in the leaves without affecting yield. This biofortification approach improved the nutritional quality of the leaves .
Conclusion
Green leafy vegetables are a valuable source of dietary iron, with their iron content and bioavailability influenced by factors such as cooking methods, utensils, and additional ingredients. Consuming GLVs with high iron content, such as Coccinia and Moringa, and using cooking techniques that enhance iron bioavailability, like cooking in iron utensils or adding vitamin C-rich ingredients, can significantly improve iron intake. These insights are crucial for addressing iron deficiency and improving overall nutritional health.
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