Tofu & Health
                                                     

Tofu reduces risk of cancer
Since roundabout 2000 years tofu has been eaten in East Asia. Modern research has proven that regular tofu consumption correlates with a reduced risk of breast and prostate cancer. In Japan approx. 80 % less cases of breast cancer are reported than in western countries. Asian women show comparably higher phytoestrogen excretions in urine, longer menstrual periods and lower levels of estrogen in plasma. This is regarded as a result of high intake of soy (in average Japanese eat tofu 2 times a week). Phytoestrogenes block receptors for endogene produced estrogen (body own) and reduce therefore their effect. An increased body own estrogen level holds a higher risk of breast cancer. The sooner tofu consumption has begun the more efficient is the minimization of the cancer risk.

Tofu protects the heart
Epidemiological studies have shown that soy protein helps preventing coronary heart diseases through the reduction of LDL (low lipo protein) cholesterol levels. The analysis of 38 clinical studies showed in 34 cases a reduction of the LDL-cholesterol levels. The levels were reduced for 12.9% in average. On top of this isoflavones from soy prevents the oxidation of the LDL-cholesterol that is made responsible for instituting blockage of the arteries. Arteriosclerosis increases the risk of coronary heart disease, heart attack and thrombosis.

Tofu preserves the bone mass
In many cases it could be proved that consumption of soy protein leads to a reduced excretion of calcium from bones and in addition to that calcium restore is positively effected. One hand tofu has high levels of the mineral complex potassium, calcium and magnesium that increases the storage of calcium in bones. Other hand the soy protein includes low levels of sulfuric amino acids that have negative effects on the body calcium level. For that reason increased animal based protein intake rich in sulfur containing amino acids lead to an increased excretion of calcium (the surplus of sulfuric compounds can only be excreted in the kidneys together with calcium).

Isoflavones/Phytoestrogen
Isoflavones occur in soy beans as genistein, Daidzein and Glycitein. Because of their structural similarity to body own estrogen they are called phytoestrogens too (phyto indicates the plant source).
Further information please find under Tofu reduces risk of cancer.

Isoflavones per 100g Tofu

Source: USDA Nutrient Database for Standard Reference, Release 13 (Nov. 1999)

Tofu rich in iron
100 g tofu has approx. 2,5 mg iron. Fundamentally the bioavailability of non-haem-iron (iron from plant sources) is lower than haem-iron (iron from animal sources). But several food combinations like vitamin C containing foods like lemon and other citrus fruits improve the iron bioavailability in tofu. So to speak a few squirts of lemon enhance the iron in tofu.

Tofu and menopause
The reduction of the estrogen level leads to the typical menopausal troubles like hot flushes and sweats. These troubles during menopause can be reduced with estrogen hormone therapies, but with the higher risk of estrogen linked cancers.
On the contrary many studies have shown the positive impact of soy protein on blood lipids, lipoproteins (cholesterol) and menopausal troubles without any changes in breast and womb tissue.
Please find below the sources, which give a reference for above information

Sources

• N Engl J Med. 333: 276-282, 1995 - Meta-analysis of the effects of soy protein intake on serum lipids.

• 3rd International Symposium on the Role of Soy in Preventing and Treating Chronic Disease vom 31. Oktober bis 3. November 1999 in Washington DC, USA

• Am J Clin Nutr 1999 Sep; 70 (3): 439-450 - Legumes and Soybeans: overview of their nutritional and health effects.

• J Ren Nutr 2000 Apr; 10(2: 63-8) - Soyfoods, soybean isoflavones, and bone health

• Public Health Nutr 1999 Dec; 2(4): 489-504 - Health potential of soy isoflavones for menopausal woman

• Nutr Review 1997 Apr; 55(4): 102-110 - Interactions of iron with other nutrients

• USDA Nutrient Database for Standard Reference, Release 13 (Nov.1999)

• Adv Exp Med Biol 1998; 442:495-9- The effect of dietary sulphur-containing amino acids on calcium exretion