Because you can study not just the effects of the supplement, but also what kind of microbes are contributing to the types of odors. This study actually seems relatively decent I think.
Edit: Abstract from sci-hub copy.
The aim of this study was to evaluate the effects of proanthocyanidin-rich extracts from grape seeds on human fecal flora and fecal odor. Proanthocyanidin-rich extract containing 38.5% proanthocyanidin was administered to nine healthy adults at a dose of 0.5 g:day (0.19
g:day as proanthocyanidin) for 2 weeks, and proanthocyanidin-rich extract containing 89.3% proanthocyanidin was administered to eight
elderly inpatients at a dose of 0.43 g:day (0.38 g:day as proanthocyanidin) for 2 weeks. Green tea extract and:or champignon extract, both of which have been found to have a deodorant effect on fecal odor, were administered in a similar manner as controls. In healthy
adults, marked decreases in fecal odor and concentrations of methyl mercaptan and hydrogen sulfide in feces were observed during
proanthocyanidin-rich extract intake, but the effects of green tea extract and champignon extract were weak. After 2 weeks of proanthocyanidin-rich extract intake, the number of Bifidobacterium had increased signifcantly (pB0.05), whereas the number of Enterobacteriaceae tended to decrease (p¾0.121). The level of putrefactive substances, including ammonia, phenol, p-cresol, 4-ethylphe- nol, indole, and skatols tended to decrease after proanthocyanidin-rich extract intake, and fecal pH also tended to decrease. Nurses and
hospital aides performed organoleptic evaluations that showed less fecal odor in elderly inpatients with proanthocyanidin-rich extract
intake than with champignon extract intake. In an in ×itro study, the proanthocyanidin-rich extract reduced methyl mercaptan and
hydrogen sulfide release from the feces of healthy adults, and also reduced methyl mercaptan release from methyl mercaptan solution. The absorptive ability of methyl mercaptan was stronger in procyanidin oligomers larger than decamer than procyanidin dimer to tetramer. These results suggest that proanthocyanidin-rich extract from grape seed intake induces a reduction in the level of putrefactive products
in the intestine, which may be linked to the modest change in the numbers of Bifidobacterium and Enterobacteriaceae. They also suggest
that the strong deodorant effect of proanthocyanidins on fecal odor is due to the decrease of putrefactive products and the absorption
of malodorous compounds from feces by the larger molecular procyanidin oligomers in the proanthocyanidins. Key words: proanthocyanidin, grape seed extract, polyphenol, fecal ora, fecal odor.
Gut microbiota: PAs can improve the diversity of gut microbes, and can increase the abundance of beneficial bacteria while decreasing the abundance of harmful bacteria.
Fecal odor: PAs can reduce the level of putrefactive substances in the feces, which can reduce fecal odor.
Fecal pH: PAs can decrease fecal pH.
Antimicrobial activity: PAs can have an antimicrobial effect on potentially pathogenic bacteria.
Prebiotic effect: PAs can have a prebiotic effect on beneficial bacteria.
Looks like I'm buying some seeded grapes for science!
I'm not into Academia. But I'm aware of this issue. But I never understood why anyone will work (review) for free an article that is being used for a company for making money.
It's literally working for free so other people get paid. Why?
Because if no one reviews the articles then anyone could publish junk. In highly technical fields the only people qualified to tell if something is BS science are the experts in the field, so they review and make sure the article has some merit.
That's not to say the reviewing process is perfect, but it does at least help to filter some amount of bs.
Obviously the one submitting the papers should not pay to influence the reviewers. Instead, it is the publishers obligation, who uses the service of the reviewers, to pay them. Just pay them the same amount if you don’t want to influence any of them & make the amount open and transparent.