Myth: Soy, especially soy milk, causes feminisation and hormonal manipulation in men as well as hormonal imbalances in women.
Justification: Soy contains plant compunds that are called isoflavones. Since these mildly imitate the function of estrogen, they are called phytoestrogens.
Many people worry that the consumption of soy products such as Edamame, Tofu, Tempeh, Soy Milk, Miso / Natto or even Soy Protein Isolate can cause an increase in estrogen levels leading to
Gynecomastia (man boobs)
A bloated face
An overall more feminine appearance
A weaker jawline
I am going to debunk these claims one by one, then explain why you should even incorporate some more soy into your diet.
Gynecomastia (man boobs)
- There is
no study out there backing the claim that moderate soy intake causes feminisation or less testosterone
- When consuming
2-3 servings of soy (equivalent to 80-120 mg isoflavones/day),
testosterone stays the same
- Gynecomastia claims come from two separate reports where people consumed 12-14 servings of soy per day for MONTHS on end (around 560-840 mg isoflavones per day)
Bloated face
- This claim comes from the association soy = estrogen
- The isoflavones in soy are weak and selective, meaning they cannot flood your body with estrogen and cause bloating
- In fact, many soy foods are
low in sodium and rich in potassium, reducing facial puffiness (see below)
A more feminine appearance
- This is a claim which originates from meme culture
- The „soy boy“ look consisting of a slouchy posture, a soft face and a skinny-fat build likely comes from a
lack of lifting, poor nutrition and low protein intake
- Soy protein is in fact a complete protein with similar qualities to whey
A weaker jawline
- There is no evidence that soy may weaken bones structure, reduce androgenic features or lessen facial masculinity
- There are little to no hormonal shifts due to soy in healthy people, but if there are any in you, that’s likely a you problem
-> I would recommend seeing a doctor
Others: Isoflavones are not hormone disrupters. They simply are weak mimics of estrogen. They do not impact Thyroid function if you maintain a healthy iodine level. Soy acts protective for breast and prostate cancer.
For ideal aesthetics, you can consume 1-3 servings of soy in a day
(Think 1 cup of soy milk, 100 g tofu, etc etc)
Why soy is not evil:
Soy is
low in sodium but high in protein and in potassium. It performs well when compared with other potassium sources and even is a
relatively cheap way to access potassium.
Let’s compare:
Soy milk: 250-400 mg potassium (1 cup)
Coconut water: 600 mg potassium (1 cup)
Banana: 420-450 mg potassium (1 medium)
Avocado: 975 mg potassium (1 medium)
While soy milk can obviously not compete with stronger potassium rich foods like avocado or banana, it is a cheaper alternative to drinking coconut water all the time as prices for 1L soy milk vary between 1,5 and 2,5€ and 1L coconut water often costs 4€+.
Benefits of potassium:
1.
Reduces water retention (bloating) through balancing sodium levels in the body -> promotes sodium flushing
2. Supports health through cell hydration for
hydrated skin
3. Promotes
muscle function through improving muscle contraction and nerve function-> benefit for workout performance and body aesthetics
4.
Improves circulation through maintaining healthy blood pressure and vascular function, can support better oxygen and nutrient delivery to skin and hair
Benefits of soy:
-
Improves elasticity and hydration of skin and may even
reduce acne through
mild DHT-blocking from the phytoestrogens
- Can
reduce hair thinning via hormonal modulation (again, DHT-blocking, especially effective in DHT-sensitive people -> see my other thread for more information on DHT)
- Soy protein contains
all 9 essential AAs, making it a full protein that supports the building and maintenance of lean muscle
-
Low sodium forms can reduce bloating (Edamame, tofu, soy milk), this does not account for highly modified products such as soy protein powder
- Fermented soy
improves your microbiome, which is crucial for
gut health, visible in form of healthy skin, improved digestion, better mood
-> Products like soy milk also have low greenhouse gas emissions and consume very little water during production!!
Bottom line:
- Soy is a cheap source of protein and potassium which is also low in sodium
- For men, it may
reduce DHT, potentially
helping with acne or hair loss
- For women, it may support
clearer skin and balanced hormones
Just like everything else, soy too should be consumed in moderation. There won’t be ANY problems with soy consumption AT ALL unless you consume INSANE amounts of soy (Think 10 blocks of tofu a day, which I doubt you consume unless you’re vegan, which would be a discussion of its own) for MONTHS on end. Please, for the love of god stop relying on „bp tiktok“ or meme culture for information and education.
SOY WILL NOT TURN YOU INTO A FEMBOY (sorry)
Sources:
Harvard T.H. Chan School of Public Health:
https://www.hsph.harvard.edu/nutritionsource/soy
NIH – National Center for Complementary and Integrative Health (NCCIH)
https://www.nccih.nih.gov/health/soy
Journal of the American College of Nutrition (Meta-Analysis, 2021):
https://doi.org/10.1080/07315724.2020.1812163
