🌿 Folk Prescriptions

Spinach and tofu soup is a traditional home-style dish cherished for its light, refreshing taste. However, modern medical studies indicate that spinach and tofu should not be consumed together. Although no such dietary combinations have been widely reported, potential harm may exist and cannot always be measured by visible signs.
[Keywords]
Tofu is high in nutrition, inorganic salts, low in fat and calories. Its rich protein content helps build strength and increase satiety, making it suitable for vegetarians and those with simple obesity. It can also reduce blood lead levels. Tofu contains substantial phytoestrogens, aiding women in achieving a shapely figure and alleviating menopausal symptoms.
Spinach contains 1.6–2.9 mg iron per 100 grams, 2.4 g protein (equivalent to two eggs per pound), 3 mg vitamin A (more than carrots), 0.06 mg vitamin B1, 0.16 mg vitamin B2, 31.4 mg vitamin C (three times that of tomatoes). Its red roots contain vitamin K, lacking in most fruits and vegetables, helping prevent bleeding tendencies in skin and internal organs. Spinach is also rich in enzymes. According to Traditional Chinese Medicine, spinach is sweet and cooling, aiding in clearing heat toxins from the gastrointestinal tract, nourishing blood, stopping bleeding, collecting yin, and moisturizing dryness. Thus, it helps prevent constipation and promotes radiant appearance. Antioxidant tests abroad show that consuming about 30 grams of fresh raw spinach provides benefits equivalent to taking 1.25 grams of vitamin C or drinking 270 grams of red wine. Spinach is thus praised as one of the "Top Ten Beauty and Skin-Friendly Foods."
[Nutritional Analysis]
Spinach is highly nutritious, earning the nickname "King of Vegetables." However, it contains a lot of oxalic acid (about 300 mg per 100 grams). Tofu contains significant amounts of magnesium chloride and calcium sulfate. When both enter the body simultaneously, they form insoluble calcium oxalate, causing calcium loss and potentially forming kidney stones. Therefore, avoid eating spinach and tofu together. Actually, spinach does not have the highest iron content, nor does it effectively replenish blood. Only 10% of iron in spinach is absorbed in the gut; the remaining 90% binds with oxalic acid into insoluble compounds, making it hard to absorb and possibly impairing iron absorption. Thus, eating spinach alone should not be excessive.
[Correct Pairings]
When calcium-to-oxalic acid ratio is 1:2, stone formation is most likely. By adjusting food pairings to disrupt this ratio, stone formation can be prevented—for example, pairing spinach with calcium-rich foods like sesame seeds, milk, or fish.
Protein quality in food depends on the types, quantities, and ratios of amino acids. Although tofu has high protein content, its low methionine (a human essential amino acid) content reduces its overall nutritional value. However, combining tofu with methionine-rich animal or plant foods can offset this weakness—for instance, adding minced meat to tofu or coating tofu with eggs before frying.
Although tofu is rich in calcium, its absorption rate is low when consumed alone. But when cooked with foods high in vitamin D, calcium absorption increases by over 20 times—for example, fish head with tofu, which is not only light and delicious but also highly nutritious.
Tofu contains various saponins, which inhibit lipid peroxidation, suppress fat absorption, and promote fat breakdown. However, saponins also increase iodine excretion, potentially causing iodine deficiency. Therefore, regular tofu consumers should increase iodine intake. Kelp is rich in iodine; pairing tofu with kelp allows for mutual benefits.