Soy-based diet

The mean dietary intake of soy isoflavones in Asian populations consuming soy-based diets ranges from 20-40 mg isoflavones/day, with upper percentile consumer intakes of 70 mg/day (corresponding to around 1 mg/kg body weight). In the six month intervention studies in Western postmenopausal women, the effective dose for improved BMD was around 80-90 mg/day, while in the one year, randomized, double-blind, placebo controlled clinical trial, the effective dose was 54 mg/day. Overall, the dietary recommendation is to consume 50 mg isoflavones/day in combination with standard nutritional requirements for calcium and vitamin D. 

J (1986) Effect of long-term feeding of soy-based diets on the pancreas of Cebus monkeys. Adv Exp Med Biol. 199 223-37. 

Three cohort studies have been performed, one in European women, and two in oriental women eating a traditional soy-based diet. The study in European women, performed by Kardinaal et al. (1998), failed to show a correlation between change in forearm bone mineral density and urinary excretion of isoflavonoids. Excretion of enterolactone, a marker of intake of grain and berries, was found to correlate positively with bone mineral density. This may be explained with the difficulty of correlating bone mineral density -a multifactorial variable, influenced by diet only on long-term basis - with excretion of phytoestrogens that only quantify the last 24 to 48 hours of phytoestrogen intake. 

Animal diet may influence in vivo imaging. Thus mice must be kept under standard alimentary condition previously tested to be sure that there are no confounding modulations of reporter expression due to the feed. For instance, alfalfa derivatives present in soy-based diets may increase abdominal autofluorescence (7). 

Isofiavones have also been found in mothers milk following consumption of roasted soyabeans or if eating a traditional Chinese diet. The possibility that feeding of soy-based infant milk could be harmful has been noted by Turner and... 

An inverse correlation between thyroid cancer risk and phytoestrogens was recently proposed as a result of a multi-ethnic population-based case control study conducted in the San Francisco Bay Area (Hom-Ross et al., 2002). In this study, dietary habits and phytoestrogen consumption were assessed by a food-frequency questionnaire and by a nutrient database. The outcome of the study was that soy-based foods and alfalfa sprouts were associated with a reduction of thyroid cancer risk, whereas a Western diet did not influence cancer risk. No difference was observed between American and Asian women or between pre- and postmenopausal women. Furthermore, among the few compounds examined, the isoflavones genistein and daidzein and the lignan secoisolariciresinol were the phytoestrogens most frequently associated with risk reduction (Horn-Ross et al., 2002). 

The study was designed to compare the effects of feeding a mixed, vegetable-based soy protein diet with a diet containing chicken. 

Various constituents in plant foods can impede Ca absorption. Plant-based diets can be high in oxalate and phytate, which are recognized as inhibitors of Ca absorption. In fact, Ca absorption is considered to be inversely proportional to oxalic acid content of the food (Weaver et al, 1999). Phytic acid poses Ca absorption problems for those species imable to endogenously synthesize phytase (e.g., humans, birds, and pigs). The Ca in CCM is chelated with the citrate and malate anions, which may make CCM less reactive than other sources of Ca toward food components known to interact with Ca " cations. For example, Lihono et al (1997a) reported data suggesting that the Ca in CCM may be less likely to complex with phytates than other Ca salts. Qn this basis, CCM may be more appropriate for the fortification of soy or other phytic acid-containing products. 

CCM is considered to ameliorate the interfering effect of phytates consumed by animals, and as a result enhance Ca absorption and bioavailability. A study in chicks by Lihono et ah (1997a) directly investigated this possibility in food derived from soy beans. The effects of microbially derived phytase enzyme treatments on the bioavailability of Ca from soy-based foods fed to young male broiler chickens were examined in two separate experiments. In experiment one, the effect of phytase was tested when day-old chicks were fed com/soybean-meal-based diets, with or without 0.12% added phytase, that also included Ca from CCM (at levels 0%, 0.1%, 0.2%, and 0.3% to provide total Ca of 0.45%, 0.55%, 0.65%, and 0.75%, respectively) or Ca from CaCOs (at the 1% level, which... 

Consumption of soy is common in children and soy-based formulae were introduced in infant nutrition about 80 years ago. Since the 1970s, use of soy-based formulae became common, and in 1980s, U.S. consumption was around 25% of that of cows milk-based formulae (NDA Opinion 2004). Soy is often introduced into the diet from an early age, often as a standard milk formula in healthy children and in children with suspected or proven cows milk allergy as a hypoallergenic substitute. However, this practice is now discouraged since a significant number of children with cows ... 

If formula diets are not used, then the type of protein used is important due to considerations of biological value and digestibility. Milk, animal proteins, egg, certain legumes, and soy products are appropriate, rich sources. If lactose intolerance is encountered, then milk should be replaced with soy-based feeds or an alternative. Fish and vegetable oils are good sources of fats as they provide generous amounts of essential fatty acids and long-chain unsaturated fatty acids. 

The bioassay was used to determine the bioavailability of zinc in milk-base and soy-base infant formulas (7). The results are shown in Figure 2 and Table 1. The low zinc basal diet contained (%) spray dried egg white powder, 20 com oil, 10 non-nutritive fibre, 3 starch, 25 biotin, 0.0004 vitamin mixture, 1 salt mixture, excluding zinc, 4 dextrose, 37. 

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