a Friend Q: I am a vegetarian, only through the beans and soy products to supplement protein. But someone told me, eating beans do not absorb iron, but also easily lead to anemia, is it true?
about beans and iron have been two very different views. Part of health experts think beans on iron useful, because one of iron was significantly higher than the number of cereals, even higher than some meat products. Another part of the experts said, beans among iron, zinc and other trace element content, although high, but very low absorption rate. If eating with attention to beans as the main source of protein for the vegetarian dangerous anemia is relatively large.
from food composition tables do not, the iron content of beans is indeed relatively high, even higher than some meat products. For example, the iron content of kidney beans can be as high as 100 grams each of 7 mg, and lean meat is 3.9 mg. However, research has long been proved that the beans were also contain a considerable number of factors hinder iron absorption, above all one of phytic acid and polyphenols. These two types of substances in the beans are important "anti-nutrient" ingredients, be able to slow down protein and starch digestion and absorption, can also reduce the absorption rate of minerals. 1984 Determination of a study found that black beans, lentils, mung beans and other food iron absorption rate was only 0.8% -1.9%.
study found that the phytic acid content of food higher, iron, zinc, calcium absorption rate lower. And many phenolic substances, even though a very good antioxidant properties, but hinder the absorption of minerals is its disadvantage. The study found that almost all kinds of polyphenols have hampered non-heme iron absorption role. In addition, the type of kidney beans which have a small amount of oxalic acid, it is common minerals hinder the absorption of plant components.
However, the beans in the phytic acid and polyphenol Although beans would greatly reduce the rate of iron absorption, but also questions will not necessarily be caused by anemia. This is because the following three reasons:
1 of phytic acid in beans and polyphenol these components only plant-derived foods the role of iron, but meat did not affect the heme iron. Meat in the form of iron to heme is sequestered status, can be successfully absorbed by the body. Therefore, as long as there is adequate dietary red meat, do not have to worry about iron deficiency problem. At present, residents of our country larger carnivorous, eating beans and happened because the risk of anemia is not too great. In contrast, male residents of hi meat substitute meat with some beans to reduce the intake of iron, but beneficial to the prevention of disease.
2 dietary vitamin C can greatly enhance iron absorption rate, so as long as the dietary intake of many rich vitamin C, food, and beans with fresh, you can very effectively offset the phytic acid and polyphenols on iron absorption effects. Other organic acids such as citric acid, malic acid, lactic acid, acetic acid, etc. will also promote iron absorption, so with fruits and vegetables and beans with iron absorption problem can be solved.
3 beans after some processing, you can significantly reduce the phytic acid components, effectively improve iron, zinc and other elements Bioavailability. The study found that soaking, germination, fermentation methods are valid. In particular, mold and yeast fermentation particularly good effect. A study found that first and then soak fermentation, beans can be removed in 88% of phytic acid. Say so, for the vegan, the酱豆腐, tempeh, miso, are very good sources of minerals.
so that the whole, in a non-vegetarian circumstances, both meat, and fruits and vegetables, because consumption iron deficiency happen beans unlikely. A lot of studies have proved this point. For animal foods for people with relatively adequate, especially obesity, high blood lipid groups, the intake of legumes, are able to receive many dietary fiber, antioxidant polyphenolic composition, have quite a wealth of B vitamins, slow digestion of starch and vegetable protein for the prevention of chronic diseases very helpful for the nutritional balance is deemed useful.
of vegan, the beans should be considered at the same time eating more fruits, vegetables, and giving priority to intake of fermented beans the categories of food in order to improve iron and other minerals plant utilization in order to avoid deficiency anemia and other questions. In addition to beans, have a lot of iron sources, such as hazelnut, almonds, black sesame and various nuts and oilseed products, as well as hawthorn, jujube, longans easier to absorb iron and other fruit.
Source:
Ann-Sofie Sandberg. Bioavailability of minerals in legumes. British Journal of Nutrition. 2002. 88: s281-285
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