Kakšni So Stranski Učinki Soje?

2024 Avtor: Cecilia Ryder | [email protected]. Nazadnje spremenjeno: 2023-12-17 14:23

Soja je široko uživana stročnica. Je glavna sestavina azijske prehrane in se uporablja kot sestavina več predelanih živil. Beljakovine v soji (sojine beljakovine) lahko nadomestijo živalske beljakovine v vaši prehrani in se pridobijo po odstranitvi zunanje lupine soje in njihovih maščobnih kislin (1), (2).

Čeprav je soja bogata s hranili, kot so kalcij, železo, cink in aminokisline, lahko povzroči določene neželene učinke (3).

Če jih zaužijete preveč, lahko vplivajo na zdravila za uravnavanje ščitnice in povzročajo neravnovesje testosterona, alergije in širjenje raka.

Dolgotrajna uporaba sojinih izdelkov v presežkih bi lahko bila nevarna. V tem prispevku obravnavamo sojo in njene možne škodljive učinke. Nadaljujte z branjem.

Kazalo

• Kaj je glavno vprašanje pri soji?
• Kaj se zgodi, ko uživate sojo? Kaj povzroča škodljive učinke?
• Kakšni so škodljivi učinki soje (sojine beljakovine)?
• Katerih sojinih izdelkov se morate izogibati?
• Koliko soje je varno zaužiti na dan?
• Je prehranjevanje preveč soje škodljivo?

Kaj je glavno vprašanje pri soji?

Glavna težava soje je vsebnost izoflavona.

Soja je rezervoar fitoestrogenov (izoflavonov), ki so strukturno in funkcionalno podobni estrogenskemu hormonu v telesu (3). Izoflavoni so razred fitoestrogenov (imenovani tudi sojini proteini), ki jih najdemo v soji in sojinih izdelkih. Naslednja tabela naj vam predstavi vsebnost izoflavona v različnih sojinih živilih.

Nefermentirana sojina hrana	Vsebnost izoflavona (mg)
sojino mleko, 1 skodelica	6.
tofu (fižolova skuta), mehka, 3 unče	20.
soja, zrela, kuhana, ½ skodelica	55
soja, suho pražena, 1 oz.	40
edamame, kuhano, ½ skodelice	16.
sojin sir, 1 oz.	2.
sojin burger, 1 patty	5.
Fermentirana sojina hrana	Vsebnost izoflavona (mg)
miso, 3 oz.	37
natto, 3 oz.	70
tempeh, kuhan, 3 oz.	30.
sojina omaka, 1 žlica	0,02

Vir: Harvard THChan School of Public Health

Sojini fitoestrogeni so bili uporabljeni za kompenzacijo pomanjkanja estrogenskega hormona. Sojine beljakovine so del nadomestnega zdravljenja z estrogenom, ki ga dajejo ženskam v menopavzi (3).

Nekatere epidemiološke študije kažejo, da lahko prehranski vnos fitoestrogenov med drugimi simptomi zmanjša pojavnost kardiovaskularnih bolezni po menopavzi, osteoporoze in vročinskih vročin. Kontrastni podatki poročajo tudi o možnosti fitoestrogenov za preprečevanje raka dojk in prostate (3).

Vendar koristi soje niso jasne. Pravzaprav nekatere druge študije tudi navajajo, da sojine beljakovine lahko povzročijo potencialno škodo (3).

Kaj se zgodi, ko uživate sojo? Kaj povzroča škodljive učinke?

Ko zaužijete sojo (sojine beljakovine) v kakršni koli obliki, se sojini izoflavoni (fitoestrogeni) vežejo na estrogenske receptorje v telesu. Ti fitoestrogeni tekmujejo z naravnim estrogenom, da se vežejo na receptorje. Posledica tega je šibka estrogena ali antiestrogena aktivnost. Z drugimi besedami, sojini izoflavoni lahko naredijo naravni estrogen v telesu manj učinkovit (3), (4).

Takšne interakcije lahko pri deklicah povzročijo hormonsko neravnovesje in povzročijo spremembe, povezane s spolom. Pri moških lahko imajo tudi antiandrogene učinke. Moški lahko začnejo rasti dojke (ginekomastija) in se znižajo koncentracije sperme, ko so na visokosojini dieti (3).

Preveliko odmerjanje izoflavona v daljšem obdobju lahko pri ženskah spodbudi endometrij (maternico) in dojke. Zato se vsem, ki so se zdravili zaradi raka dojke, običajno priporoča, da se izogibajo sojinim beljakovinam (3).

Fitoestrogeni lahko vplivajo na več fizioloških in patoloških procesov v telesu. Veliki odmerki sojinih izolatov lahko povzročijo škodljive učinke na razmnoževanje, kožo, prenovo kosti, kardiovaskularni sistem, živčni sistem, imunski sistem in metabolizem.

Oglejmo si podrobno škodljive učinke soje (sojine beljakovine).

Kakšni so škodljivi učinki soje (sojine beljakovine)?

1. Lahko posega v regulacijo ščitnice

Sojina hrana lahko poveča tveganje za razvoj hipotiroidizma pri ljudeh z oslabljenim delovanjem ščitnice. Takšni posamezniki lahko razvijejo golšo in avtoimunsko bolezen ščitnice. To tveganje se še poveča, če je posameznikov vnos joda nizek (5).

Ugotovljeno je bilo, da sojini izoflavoni zavirajo delovanje encima, imenovanega ščitnična peroksidaza. Ta encim je potreben za sintezo ščitničnega hormona. To je razlog, da se lahko soočate s tveganjem za hipotiroidizem, če jeste veliko sojinih beljakovin (6).

Sojini izdelki vplivajo tudi na absorpcijo levotiroksina (L-tiroksin), zdravila za zdravljenje pomanjkanja ščitničnega hormona (7). Ker se zdi, da sojine beljakovine spreminjajo razpoložljivost zdravil, vam morda odsvetujejo uživanje sojinih beljakovin, če imate neravnovesje ščitnice.

Zdi se, da le visok vnos sojinih izoflavonov ne povečuje tveganja za hipotiroidizem, razen če je skupaj z neustreznim uživanjem prehranskega joda. Zato je vpliv sojinih beljakovin na ščitnico sporen. V zvezi s tem je potrebnih več raziskav.

2. Lahko povzroči neravnovesje testosterona

Študija je bila izvedena na 12 moških, ki so štiri tedne dnevno uživali 56 g izolata sojinih beljakovin. Posledično se je njihova raven testosterona v serumu zmanjšala za 19% (8). Čeprav so bili podatki nedosledni, je bilo ugotovljeno, da sojini proteini znižujejo raven testosterona v serumu pri zdravih moških.

Sojine beljakovine naj bi škodljivo vplivale na reproduktivno funkcijo moških. Vendar v zvezi s tem ni posebnih študij. Nekatere študije na živalih dejansko navajajo, da sojini izoflavoni na moške nimajo feminizirajočih učinkov (9).

Most of the observations are based on lab and animal studies. Hence, the relationship between soy isoflavones and testosterone is inconclusive (10).

3. May Elicit Hypersensitivity (Allergy)

Soy products can cause allergies or hypersensitivity in children and adults. Often, soy allergy starts in infancy, with reaction to soy-Soy products that can cause allergies or hypersensitivity in children and adults. Often, soy allergy starts in infancy with a reaction to soy-based infant formula. However, most children outgrow soy allergy (11).

Generally, soy allergy is uncomfortable but not severe. An allergic reaction to soy is rarely frightening or lethal. Symptoms of soy allergy may include tingling in the mouth, eczema or itchy skin, wheezing, diarrhea, stomach ache, vomiting, and skin redness (flushing) (12).

If you experience any of these symptoms, you may have a soy allergy. Get tested to confirm the allergy. If tested positive, you may be advised against having soy products/isoflavones.

4. May Increase The Risk Of Cancer Proliferation

Soy isoflavones (one of them being genistein) may stimulate the proliferation of cancer cells in your body. This is especially true in the case of estrogen-dependent breast cancer, as soy isoflavones tend to have estrogenic effects (13).

As per animal studies, genistein may deregulate the cell cycle and trigger tumor development. It acts by triggering the estrogen receptors (14).

Contrarily, human studies show an inverse relationship between cancer and isoflavones. Soy intake was also found to reduce the incidence and death rate caused due to breast cancer. This could be because of the anti-estrogenic effect exerted by phytoestrogens (13).

The amount and source of soy isoflavones also greatly impact breast cancer risk (14).

5. May Trigger Alzheimer’s Dementia

Traditionally, soy foods were used in cooking only after fermenting. This two-step routine would destroy most of the anti-nutrients in soy, such as isoflavones (like genistein and daidzein) and DNA-altering enzymes (like topoisomerases) (15).

When you eat unfermented, cooked/uncooked soy foods, these anti-nutrients may affect the vital systems of your body, including your brain (15).

These anti-nutrients in soy could have detrimental effects on many individuals. Soy isoflavones could increase the risk of Alzheimer’s dementia (15).

If you are dealing with dementia or have a family history of this condition, it is safe to reduce your soy consumption (15).

6. May Cause Infant Health Issues

Infant food formulas contain fair amounts of soy protein/isoflavones. Infants who are fed these formulas are exposed to 5.7–11.9 mg isoflavones/kg body weight during the first four months of life (16).

These kids are exposed to 6–11 times higher levels of isoflavones than adults. This could lead to disturbances in the reproductive health and endocrine function in the child. The major isoflavones, daidzein and genistein, preferentially bind to the estrogen receptors in the body (16).

However, these conclusions are based on animal studies. Human studies may give a different picture. Moreover, currently available soy-based formulas show no overt toxicities in healthy infants (16), (17). Hence, check with your pediatrician before giving soy-based formulas to your child.

7. Unsure Osteoprotective Effects

Soy protein has shown to conserve bone mineral density, particularly in postmenopausal women. In perimenopausal women, the soy isoflavones were shown to prevent bone loss from the lumbar spine. These compounds had no significant effect (neither positive nor negative) on bone formation and/or bone resorption (18).

In some cases, the mineral balance could be impaired with soy consumption. Soybeans contain (by weight) about 1–3% phytic acid (also called phytate). Phytic acid is an anti-nutrient that binds to minerals like zinc, iron, and calcium. Along with soy isoflavones, phytic acid also may decrease their bioavailability (18).

However, a major chunk of literature highlights the osteoprotective effect of soy protein. Further research is needed to determine the precise impact of soy protein/foods on bone density and other related diseases (19).

Most of the research on soybeans and soy protein is still unclear. While in some studies they seem to promote health, certain other studies tend to state the potential harm they may cause. However, this does not mean you have to totally be off soy. There are a few specific soy products you may want to avoid.

Which Soy Products Should You Avoid?

Moderation is important, and so is eating right. Choosing the right kind of soy products can protect you from the adverse effects mentioned above.

When given a choice between natural soy foods and soy protein isolate, go for the natural options. Avoid industrial soy foods if you have iodine deficiency or thyroid imbalance (15).

Whole soy foods are mostly fermented and cooked in a healthier manner. You can take tofu, edamame, soy milk, tempeh, miso, and natto a few times every week.

How Much Soy Is Safe To Eat In A Day?

According to the US FDA, daily consumption of 25 g of soy seems to be safe. This amount of soy could also help lower cholesterol levels (20).

It also is believed that the intake of 50 g of soy protein per day could help prevent heart disease, diabetes, and estrogen-dependent cancers. However, more research is warranted.

There is limited information on the excess intake of soy protein/soybeans. But we don’t recommend you take more than 25 grams per day.

Is Eating Too Much Soy Harmful?

There is little information about the toxicity of soy protein. In limited doses, soy protein may be helpful for women who are at a high risk of breast cancer (21).

Some studies reported very few drug-related adverse events, which were mild. In very few cases, high levels of soy isoflavones adversely affected blood pressure levels (22).

Hence, it is important you talk to your healthcare provider about a suitable dosage for you.

Conclusion

Soy protein could be the reason Asians have historically had lower rates of cardiovascular disease. Their menopausal symptoms and incidence of breast cancer, diabetes, and obesity are also lower than their Western counterparts (23).

There is substantial yet unclear evidence stating the adverse effects of soybeans and soy protein/foods. Soy isoflavones may disturb the hormonal balance, stimulate cancer proliferation, and trigger allergies.

Hence, choose your soy portions carefully. Pick fermented soy foods over protein or isoflavone isolates. Follow the instructions by your physician/nutritionist and stick to the recommended intake limit.

23 sources

Stylecraze ima stroge smernice za nabavo in se opira na strokovne študije, akademske raziskovalne ustanove in zdravniška združenja. Izogibamo se uporabi terciarnih referenc. Več o tem, kako zagotavljamo, da je naša vsebina natančna in aktualna, lahko preberete v naši uredniški politiki.

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