D-sorbitol 6-phosphate + NAD(+) = beta-D-fructose 6-phosphate + H(+) + NADH Carbohydrate metabolism; D-sorbitol degradation; D-fructose 6-phosphate from D-sorbitol 6-phosphate: step 1/1. Homotetramer. Belongs to the short-chain dehydrogenases/reductases (SDR) family.