Answer:

Soy protein can contain plant estrogens (phytoestrogens), known as isoflavones. Whey protein (which is made from cow's milk) can also contain these isoflavones (due to soy in cow feed) as well the hormone estradiol (an estrogen) that is naturally found in cow milk. However, as explained in our Protein Powders Review, amounts of estrogens or phytoestrogens in whey protein powders are very small and unlikely to be of any significance. Higher concentrations of phytoestrogens are found in soy protein powders but, as also explained in the Review, these are lower than the amounts in soy flour and levels vary considerably based on how the soy protein was extracted.

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3 Comments

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Laura17767
April 17, 2019

Is it possible that whey protein isolate powder can make you bloated or even gain weight?

ConsumerLab.com
April 22, 2019

Hi Laura - Whey protein can cause gas and bloating (see the Concerns and Cautions section of the Protein Powders, Shakes and Drinks Review: https://www.consumerlab.com/reviews/Protein_Powders_Shakes_Drinks_Sports/NutritionDrinks/#concerns). It’s possible that whey protein could contribute to weight gain if you are consuming, overall, more total calories during the course of the day than you need. Also keep in mind in mind that the liquid you mix the protein powder with can add extra sugar, fat and calories – see the chart in the Review for carbohydrates, fats and proteins found in liquids commonly mixed with powders: https://www.consumerlab.com/reviews/Protein_Powders_Shakes_Drinks_Sports/NutritionDrinks/#mixing.

LYNN17762
April 17, 2019

Soy products cause me to have more frequent episodes of epilepsy. A little is OK, but not a cup of soy milk or tofu. The type of epilepsy I have causes me to have a feeling of deja vu, an unpleasant feeling, a wave that "breaks" over me from head to toe, and a tired feeling afterwards. I'm totally aware and functional through these brief, about 2 minutes, episodes. When I went through menopause it fluctuated in frequency more than usual,then became very infrequent post-menopause. Soy definitely has estrogens that can harm.

Pat17761
April 17, 2019

Where can estrogen be found in foods?

ConsumerLab.com
April 17, 2019

Hi Pat - As noted above, products made from cow's milk that contain some fat, most likely contain some estrogen. Products made from soy contain isoflavones. See the chart "Getting Isoflavones from Foods" in the Menopause Supplements Review for amounts found in common soy-based foods: https://www.consumerlab.com/reviews/soy-isoflavones_red-clover_black-cohosh_supplements/phytoestrogens/#food.

Pat17765
April 17, 2019

thank you so much1

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