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Which amino acid is low in legumes such as beans?
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Amino acid
The structure and function of amino acids.
Legumes such as beans are considered incomplete protein sources because they are low in the essential amino acid methionine.1
While legumes are high in lysine, they lack sufficient quantities of methionine to meet human protein requirements on their own. To address this, these foods are often paired with grains, which have complementary strengths and weaknesses; for example, combining beans with rice provides a more complete amino acid profile.1