Should we be dropping soy from the menu?

Debunking myths about soy intake on thyroid function

- CHESHIRE QUE, RND, RN, RD

Have you been diagnosed with hypothyroidism or an underactive thyroid gland? Were you told to avoid soy and soy product's like tofu and taho? What is the basis for this recommendation? Where did this connection between the thyroid gland and soy intake come from?

Soy’s reputation has been demonized for decades. Being called an endocrine disruptor and accused of wreaking havoc with not only the thyroid hormone balance, but also said to be a risk factor for breast cancer. These are all myths. Recent studies have shown that advising individuals against the consumption of wholesome sources of soy is outdated. The basis for that kind of advice is based on animal and laboratory studies, not human trials.

In 2021, researchers Mark Messina and colleagues conducted a technical review of the observational and clinical data to examine the association between soy or isoflavone intake and endocrine-related endpoints. After analyzing 229 observational studies, 157 clinical studies, and 32 systematic reviews and meta-analyses, their team concluded that the available evidence gathered and reviewed indicated that intake of soy has no adverse effect on the function of the thyroid gland.