Broccoli or Sulforaphane: Is It the Source or Dose That Matters?
AI Summary
This comprehensive review examines the current state of research on sulforaphane, a compound formed from glucoraphanin found in broccoli and broccoli sprouts. The researchers note that sulforaphane was first isolated from broccoli in the early 1990s and has since been the subject of over 3,000 publications demonstrating its protective properties in animal disease models. The review highlights that sulforaphane is formed through the action of myrosinase enzyme, which can be found either in plant tissue or in the human microbiome. The authors emphasize significant challenges in translating promising animal research to human applications, particularly regarding optimal dosing and administration methods. While over 50 clinical trials have examined sulforaphane's effects in humans, the review suggests more research is needed to understand underlying mechanisms and develop reliable biomarkers for measuring its activity in people. The authors conclude that substantial changes in research approach will be necessary to realize sulforaphane's potential public health benefits across diverse populations.
Key Findings
- Over 3,000 publications have documented sulforaphane's efficacy in animal disease models since its isolation from broccoli in the early 1990s
- More than 50 clinical trials have examined sulforaphane's pharmacokinetics, pharmacodynamics, and disease prevention effects in humans
- Sulforaphane is formed from glucoraphanin through myrosinase enzyme action, present in either plant tissue or human microbiome
- Significant challenges exist in translating animal research to clinical applications, particularly regarding dose selection and administration routes
Abstract
There is robust epidemiological evidence for the beneficial effects of broccoli consumption on health, many of them clearly mediated by the isothiocyanate sulforaphane. Present in the plant as its precursor, glucoraphanin, sulforaphane is formed through the actions of myrosinase, a β-thioglucosidase present in either the plant tissue or the mammalian microbiome. Since first isolated from broccoli and demonstrated to have cancer chemoprotective properties in rats in the early 1990s, over 3000 publications have described its efficacy in rodent disease models, underlying mechanisms of action or, to date, over 50 clinical trials examining pharmacokinetics, pharmacodynamics and disease mitigation. This review evaluates the current state of knowledge regarding the relationships between formulation (e.g., plants, sprouts, beverages, supplements), bioavailability and efficacy, and the doses of glucoraphanin and/or sulforaphane that have been used in pre-clinical and clinical studies. We pay special attention to the challenges for better integration of animal model and clinical studies, particularly with regard to selection of dose and route of administration. More effort is required to elucidate underlying mechanisms of action and to develop and validate biomarkers of pharmacodynamic action in humans. A sobering lesson is that changes in approach will be required to implement a public health paradigm for dispensing benefit across all spectrums of the global population.
Authors
Yoko Yagishita, Jed W Fahey, Albena T Dinkova-Kostova, Thomas W Kensler