Soy Consumption Linked to Digestive and Thyroid Risks.

In 2007, Begoña Cerdá and a team studied six volunteers whose fecal samples were incubated with ellagic acid, a soy polyphenol. They found gut bacteria turned it into urolithin, a compound tied to gut inflammation and potential cancer risk in animal studies, with 30-50% more urolithin production in some people, suggesting soy may harm gut health in certain individuals.

In 2019, Luyao Ma and colleagues reviewed animal and human studies on soy isoflavones, like genistein, and their impact on thyroid function. In rats, high doses caused thyroid enlargement and 30-40% lower thyroid hormone levels, risking hypothyroidism, especially in females. Human data showed similar risks for those with low iodine, with 20-25% higher hypothyroidism odds in regular soy consumers.

Limit soy intake, especially if you have thyroid issues or low iodine, and opt for whole milk instead.