Do Brassica Vegetables Affect Thyroid Function?-A Comprehensive Systematic Review.
AI Summary
This comprehensive systematic review examined the longstanding concern about whether brassica vegetables (including broccoli and broccoli sprouts) might negatively affect thyroid function. Researchers analyzed 123 studies including in vitro, animal, and human research to assess the impact of these vegetables and their compounds (glucosinolates and isothiocyanates) on thyroid health. The study investigated various thyroid markers including TSH, T3, T4 levels, iodine uptake, thyroid mass, and effects on thyroid cancer cells. The findings challenge previous assumptions about brassica vegetables being harmful to thyroid function. For individuals considering sulforaphane supplementation from broccoli sprouts, this research provides reassuring evidence that consuming these vegetables as part of a regular diet appears safe for thyroid health, particularly when adequate iodine intake is maintained. This is particularly relevant since concerns about thyroid effects have sometimes discouraged people from consuming these nutritionally valuable vegetables.
Key Findings
- Analysis of 123 studies cast doubt on previous assumptions that brassica plants have antithyroid effects in humans
- Including brassica vegetables in daily diet poses no adverse effects on thyroid function when accompanied by adequate iodine intake
- Researchers examined multiple thyroid markers including TSH, T3, T4 levels, iodine uptake, and thyroid mass across in vitro, animal, and human studies
Abstract
Brassica vegetables are widely consumed all over the world, especially in North America, Asia, and Europe. They are a rich source of sulfur compounds, such as glucosinolates (GLSs) and isothiocyanates (ITCs), which provide health benefits but are also suspected of having a goitrogenic effect. Adhering to PRISMA guidelines, we conducted a systematic review to assess the impact of dietary interventions on thyroid function, in terms of the potential risk for people with thyroid dysfunctions. We analyzed the results of 123 articles of in vitro, animal, and human studies, describing the impact of brassica plants and extracts on thyroid mass and histology, blood levels of TSH, T3, T4, iodine uptake, and the effect on thyroid cancer cells. We also presented the mechanisms of the goitrogenic potential of GLSs and ITCs, the limitations of the studies included, as well as further research directions. The vast majority of the results cast doubt on previous assumptions claiming that brassica plants have antithyroid effects in humans. Instead, they indicate that including brassica vegetables in the daily diet, particularly when accompanied by adequate iodine intake, poses no adverse effects on thyroid function.
Authors
Agnieszka Galanty, Marta Grudzińska, Wojciech Paździora, Piotr Służały, Paweł Paśko