1. Introduction
obesity, infection, flatulence
OBESITY, ADVERSE EVENTS, INFECTION, SECONDARY, HEAT
Soybean products have nutrients, dietary fiber, and phytoalexins beneficial for cardiovascular and overall health. Despite their high consumption in Asian populations, their safety in Western diets is debated. We conducted a dose-escalating clinical trial of the safety and tolerability of soybean products in eight older adults (70–85 years) with obesity. Whole green soybean pods grown under controlled conditions were processed to flour (WGS) at the United States Department of Agriculture using common cooking techniques such as slicing and heat treatment. WGS incorporated into food products was consumed at 10 g, 20 g, and 30 g/day for one week at each dose. The gastrointestinal outcomes, clinical biomarkers, and adverse events were evaluated. We explored the stimulation of phytoalexin (glyceollin) production in live viable soybean seeds (LSS-G). We compared the compositions of WGS and LSS-G with commercial soybean flour and its fermented and enzymatically hydrolyzed forms. We found that although 30 g WSG was well-tolerated, and it made participants feel full. Our processing produced glyceollins (267 µg/g) in LSS-G. Processing soybean flour decreased the iron content, but reduced the oligosaccharides, which could attenuate flatulence. Providing soybean flour at <30 g/day may be prudent for overall health and to prevent the exclusion of other food groups and nutrients in older adults with obesity.Plants produce an array of secondary metabolites that are non-essential for basic metabolic processes, but have evolved to bestow a selective advantage against microbial or predatory attacks. These compounds are functionally defined as phytoalexins, which are synthesized de novo by the plant in response to stress, and phytoanticipins, which are pre-formed infection inhibitors. Phytoalexins are toxic to microbes but have biological activities that confer health benefits on other species [We investigated the concept of injuring plant cells by slicing whole green soybean pods to induce stress, and found that it stimulated the production of glyceollins when subsequently incubated [Soybeans needed to be harvested at a particular reproductive stage and processed within 24 h of harvesting for glyceollin production by our processing method. Our facilities are located in Louisiana where the soybean harvesting period coincides with hurricane season, which poses many challenges for the production of glyceollin-enriched WGS. The 24-h time limitation for processing required a close proximity between the laboratory and harvesting site, which precluded obtaining fresh green soybeans from other growers. For the clinical trial reported in this paper, because of the seasonal limitations and Covid-19 restrictions from the United States Department of Agriculture (USDA), New Orleans, LA processing facility, incubation of the sliced WGS necessary for glyceollin synthesis was precluded [Soybean products and consequently isoflavones form part of the traditional diets in Asian cultures. Despite their high consumption in Asian populations, some debate about their safety in the Western diet still pervades the literature [