Potential Benefits of Spices in Moderating Blood Pressure

Singletary, Keith, W., PHD

Objectives
This narrative review provides a summary of human studies evaluating the effects of select spices on glucose homeostasis and highlights areas for future research. This narrative review is intended to be a descriptive study of the scientific literature on the effects of spice interventions on hyperglycemia in humans so as to clarify the current state of knowledge and identify knowledge gaps for the reader, rather than to suggest guidelines for clinical decision-making and policy development.

Methods
Spices selected for evaluation in this narrative review were those for which meta-analyses examined their effects from at least 2 to 3 randomized controlled trials (RCTs). Evidence from umbrella reviews also was included.

Results
The search identified meta-analyses satisfying the search criteria that examined the following spices: black seed, cardamom, cinnamon, fenugreek, garlic, ginger, ginseng, onion, red pepper, saffron, sesame, sumac, and turmeric. For the meta-analyses included in this review, there was considerable variability in the quality of the RCTs. Publication bias determined by the Begg and Egger methods usually was concluded to be low for most RCTs assessed. Taken together, these issues of disparities in trial procedures and quality prevent drawing strong evidence-based conclusions and contribute uncertainty concerning recommendations that can be provided about spice intake and improvements in high blood pressure.

Conclusions
For several of the spices administered to humans, outcomes reported from these meta-analyses were mixed, and little evidence of improved BP was apparent; however, there is promising evidence that select spices may be appropriate adjuncts in the management of high blood pressure. Future research that addresses several issues can increase the robustness of evidence relating to the intake of spices for decreasing elevated blood pressure.

Reference
Singletary, K.W. Potential Benefits of Spices in Moderating Blood Pressure. Nutrition Today. Volume X, Number X, X/X 2025. DOI: X