Residue from soybean oil production alleviates menopause – 12/05/2023 – Balance

Almost everyone has heard the saying that “eating soy is good for women’s health”. In recent decades, several studies have been carried out based on the observation that Eastern women, whose diet is rich in soy, presented few (or none) of the symptoms related to menopause reported by Western women: hot flashes, insomnia, irritability and depression, among others. .

Thus, soybeans were the target towards which the scientific community turned in the search for explanations for the phenomenon.

“Soy isoflavones are important sources of bioactive compounds and belong to a class of phytoestrogens, that is, substances similar to estrogen, which can provide health benefits. However, they are poorly absorbable by the gastrointestinal tract, as they are normally found in glycosylated form [ligada à glicose]”, says Gabriela Alves Macedo, professor at the Faculty of Food Engineering at the State University of Campinas (FEA-Unicamp).

“In order for them to exert their effects on health, they must be metabolized by the microorganisms of the intestinal microbiota, forming isoflavones, aglycones [sem glicose] and its bioactive secondary metabolites, such as equol, which has a structure very similar to that of estrogen” explains Macedo.

First author of an article published in the magazine Foods, Macedo recalls that the drop in estrogen production observed during menopause is responsible for several physiological and behavioral changes in women. Therefore, it is estimated that so-called phytoestrogens, such as equol, can minimize the undesirable symptoms of menopause.

“It turns out that not every woman can metabolize soy isoflavones, because not everyone has an intestinal microbiota capable of doing so. So, with the help of colleagues, I have been trying to obtain a product that already contains equol and, therefore, can benefit women who cannot metabolize isoflavones.”

In the recently published work, the team mimicked the human microbiota in order to understand how the isoflavones contained in soy extract are metabolized by microorganisms. According to Macedo, it is also possible to obtain this extract from the residue from the manufacture of soybean oil, called okara.

“It is possible to extract both protein and phenolic compounds. As a food engineer, I always think about the possibility of using waste. In our country, I see no other source more promising than soy for obtaining the extract on an industrial scale, although all vegetables rich in isoflavones can eventually generate equol.”

The work was supported by Fapesp through a postdoctoral scholarship granted to Cintia Rabelo and Paiva Caria, second author of the article.

Mimicry

The team produced the soy extract in order to obtain the most interesting initial isoflavone concentration for the experiment.

“The industrial process for obtaining the soy extract used in drinks found in supermarkets is inefficient from the point of view of extracting phenolics. It focuses on protein, because these drinks aim to serve as a source of non-animal protein.”

To mimic the metabolization of isoflavones contained in the extract and obtain equol, the group used different processes.

“In the first, we apply enzymes [uma mistura de moléculas, entre as quais a beta-glicosidase] to remove glucose from glycosylated isoflavones. In this case, we carried out a subsequent measurement to verify whether, just by using the enzyme, it would be possible to obtain any metabolite of interest, in addition to quantifying the glycosylated isoflavones and aglycones at the end of the process.”

A second strategy was to ferment the extract with a mix of lactobacilli. The group inoculated the extract with lactic acid bacteria in anaerobiosis [sem oxigênio] and analyzed isoflavones before and after fermentation.

In the third process, the group combined the use of the enzyme and probiotics. “After the action of the enzyme, I inoculated the probiotic mix. The idea, in this case, was to facilitate the work of the lactobacilli, doing half the way with the enzyme in an attempt to speed up the process and obtain more metabolites at the end. We found that, in fact, this combined process works better: the samples that went through it showed greater antioxidant capacity, more isoflavone transformation metabolites and better conversion of glycosylated isoflavones into aglycones. The combination of both treatments showed a synergistic effect on soy-based products .”

According to Macedo, the group was concerned with testing processes that could be replicated at an industrial level. Therefore, he worked with an enzyme and a mix of commercial probiotics. “We have to develop things that make sense from a technological point of view.”

Effect and contraindication

The researcher reiterates that, because equol is a compound very similar to estrogen, the estrogen receptors in the ovary, uterus and breast cannot identify the difference and perceive the substance as if it were the hormone.

As a result, the body does not react to the lack of estrogen [sintomas da menopausa]because you think he is present.

“This is the idea behind obtaining compounds that mimic estrogen. They also exist in mulberry leaves, yams and other vegetables. But I don’t know if they are more bioavailable in these sources or if they also need some type of transformation to to be absorbed by the body.”

According to her, according to existing knowledge on the subject, the principle of action of phytoestrogen is the same as that of hormone replacement therapy, although, obviously, in much lower concentrations.

“There are already products on the market with soy extract or milk, including some indicated for menopausal symptoms, but they do not work for everyone. As each person has a different microbiota, the idea is to design a product already with phytoestrogen, without depending of the metabolization of each individual’s microbiota, and thus reduce symptoms in general.”

However, women who have breast or ovarian cancer and are estrogen responsive (in which cases the tumor uses the hormone to grow) cannot take hormone replacement therapy and, therefore, should not ingest these extracts rich in phytoestrogen.

“There are also some types of prostate cancer that are responsive to estrogen. People affected by these diseases will not be able to consume the products we are looking for.”

Next steps

Macedo also explains that equol is a molecule with the ability to form two forms: R-equol and S-equol. “Only one of them is absorbed by the body. But, in the process of obtaining the metabolite, we were unable to separate them. So, we went two ways: through chromatography we were able to identify equol and differentiate it from other metabolites of interest, but we do not have how to know which of the two molecular forms is present, as the concentration is very low. So, we have carried out in vitro studies with human cancer cells to test the estrogenic effect of the extracts obtained.”

The team treats the cells with soy extracts that have already been processed by enzymes and fermentation: if they multiply even more, it means that the extract has an estrogenic effect.

“In this work published in Foods, which is not our first on the subject, data from tests on cells were missing, which we intend to publish now”, he adds.

Despite this, according to the engineer, through simulated in vitro digestion it was possible to prove that the body “keeps” both the antioxidant effect and the benefits provided by isoflavones.

“Our goal was to find out which process was most efficient in the biotransformation of isoflavones. And also whether it would be good enough to guarantee the availability of the resulting material for absorption by the body. Theoretically, if we can simulate these digestions well, there is an absorption effect and the metabolite circulates in the blood. So, I believe we are close to our goal. I want to obtain a food-grade product that also benefits those who cannot metabolize isoflavones, but who also suffer from the symptoms of menopause.”

The article Bioaccessibility Evaluation of Soymilk Isoflavones with Biotransformation Processing can be accessed at www.mdpi.com/2304-8158/12/18/3401.