A clinical trial led by Osaka Metropolitan University has found that a spice commonly used in curry may have anti-obesity benefits.
Nigella sativa (black cumin) is a spice that boosts the flavour of curries such as korma and paneer.
It also has other uses, with its seeds long used as a medicinal plant in traditional medicine for their antioxidant and anti-inflammatory effects.
The new clinical trial suggests that they also have anti-obesity benefits.
To investigate these effects, a team led by Associate Professor Akiko Kojima-Yuasa of the Graduate School of Human Life and Ecology used cellular experiments and human clinical trials.
In the human clinical trial, participants who consumed 5 g of black cumin seed powder daily — roughly a tablespoon — for eight weeks showed significant reductions in blood triglycerides, LDL ('bad') cholesterol and total cholesterol levels.
In addition, HDL (‘good’) cholesterol levels increased.
Improvements in blood lipid profiles such as these are associated with a lower risk of heart problems and premature death.
The group also performed cellular experiments to understand the processes involved.
They found that black cumin seed extract inhibited adipogenesis — the formation and maturation of fat cells — by blocking both fat droplet accumulation and the differentiation process.
“This study strongly suggests that black cumin seeds are useful as a functional food for preventing obesity and lifestyle-related diseases,” Professor Kojima-Yuasa said.
“It was so gratifying to see black cumin comprehensively demonstrate actual, demonstrable blood lipid-lowering effects in a human trial.”
“We hope to perform longer-term and larger-scale clinical trials to investigate the effects of black cumin on metabolism,” she added.
“We are particularly interested in investigating its effects on insulin resistance in diabetes and inflammatory markers.”