Soy Products for Weight Loss

I didn't notice that soy products are healthy until I developed Diabetes and high cholesterol in the US. In Japan, we eat a lot of soy products every day. Tofu in the miso soup. Tofu and miso are soy products. We eat Nato, fermented soybeans in our breakfast. Edamame is a salt-boilded baby soybean. We dip some food in soy sauce. We flavor some food with miso or soy sauce. Some people drink soy milk.

Soybeans are excellent source of protein, unsaturated fat, vitamins, and minerals, isoflavones, and fibers. One cup of soybeans provides 57.2% of the Daily Value for protein, less than 300 calories, only 2.2 grams of saturated fat, and 41.2 % of the DV for omega-3.

Soybeans are also the most abundant source of isoflavones in food. Clinical studies suggest that soy protein or isoflavones may improve metabolic parameter. A meta-analysis of 38 trials as well as more recent reports demonstrated a significant reduction in plasma concentrations of total and LDL cholesterol (bad cholesterol) in humans exposed to soy proteins. In addition, postmenopausal Japanese women treated for 24 weeks with isoflavones exhibited a lower fat mass. Obese patients treated with soy protein isolates for 12 weeks had lower body weight and BMI, with decreased cholesterol and LDL levels in the blood.Additionally, a 6-month clinical trail was conducted with isoflavones on blood glucose, insulin, and lipid profiles in postmenopausal Taiwanese women. The study revealed that during fasting both glucose and insulin levels were significantly reduced by soy isoflavones. However, a significant number of studies reported an absence of beneficial effects of soy. These discrepancies are probably due to the variety of experimental designs and exposition protocols, the capacity of individuals to produce equol which is a product metabolized from daidzein, a type of isoflavone by bacterial flora in the intestines which only about 30-50% of people have and the genetic susceptibility. Most rodent studies showed an improvement in total cholesterol and/or triglyceride levels after consumption of dietary soy, soy protein isolates, isoflavones or genistein (one of the predominant isoflavones in soy). Only one study shows an absence of effects on total cholesterol and triglyceride after consumption of soy protein isolates.

Isoflavones are structurally similar to estradiol and mimic its effects. Due to the possible estrogen-like effects, it is concerned that it may promote or propagate estrogen-sensitive cancers. This concern is based on in vitro and rodent data which suggest that genistein can stimulate tumor cell proliferation and growth in mice having deficient immune systems. However, a recent nested case-control study and meta-analysis of numerous epidemiological studies show an inverse correlation between genistein intake and breast cancer risk. Furthermore, clinical studies in osteopenic and osteoporotic postmenopausal women support the breast and uterine safety of purified naturally derived genistein administrated for up to 3 years.

Therefore, soy products are safe and have strong health promoting effects.

As a note, soy sauce and soybean oil don't contain isoflavones.