Plate Nº 86 · recorded October 10, 2026
Health & Medicine ResearchReported finding
Black and Green Rice Digest More Slowly Than White Rice, Study Finds
Hokkaido University scientists found 196 lipid molecules in 56 japonica rice cultivars. Black and green varieties digested more slowly than white rice in lab tests, suggesting gentler blood sugar responses.
By Priya Raman4 min read745 words
In brief
- Researchers identified 196 lipid molecules across 56 japonica rice cultivars, published in Food Research International in 2026.
- FAHMFAs, a potentially beneficial lipid class, were detected in rice for the first time.
- In lab digestion tests, black and green rice broke down more slowly than white rice, suggesting a gentler blood sugar rise.
- Japonica rice makes up about 15% of global rice consumption; starch forms over 85% of the grain.
Black and green Japanese rice may raise blood sugar more gradually than ordinary white rice, according to a study published in Food Research International in 2026. Researchers at Hokkaido University also found that these colorful varieties contain unusual fats never before detected in rice, including one class identified in the grain for the first time.
The team, led by Associate Professor Siddabasave Gowda, analyzed 56 cultivars of japonica rice — the short- to medium-grain type that turns soft and slightly sticky when cooked and accounts for roughly 15% of rice consumption worldwide. Their samples included brown, red, green, and black varieties collected from across Japan.
The results point to two potential health advantages packed into the same grain: distinctive lipids with previously observed anti-inflammatory and metabolic benefits, and a starch structure that breaks down slowly during digestion.
What did the researchers actually find?
Using liquid chromatography and mass spectrometry — techniques that separate and identify molecules at very fine detail — the scientists mapped the fats present in japonica rice. They identified 196 different lipid molecules spanning five major groups.
That number matters because rice fat has long been overlooked. More than 85% of the rice people eat consists of starch, with protein at around 10% and fat at roughly 2%. Because lipids make up such a small share, they have received far less scientific attention than starch, even though they influence nutrition, flavor, and grain quality.
"Although lipids make up only a small proportion of rice, they are critical in determining its nutritional value," Gowda explains. "They help maintain cell membrane integrity, store energy, and support essential signaling processes in the body."
Among the 196 molecules, two groups stood out in black and green rice specifically:
- FAHMFAs (fatty acid esters of hydroxy medium-chain fatty acids) — detected in rice for the first time in this study.
- LNAPEs (N-acyl-lysophosphatidylethanolamines) — another potentially beneficial lipid class.
In certain biological systems, these types of lipids have previously been linked to anti-inflammatory activity and improved metabolic health. Pigmented varieties, especially black and green rice, scored higher on the researchers' health-promotion index thanks to these distinctive lipid profiles.
How did they test the blood sugar effect?
The researchers did not feed rice to human volunteers. Instead, they recreated key steps of human digestion in the laboratory. They cooked selected rice samples, treated them with digestive enzymes, and measured how quickly the starch in each sample broke down. That rate offers an indication of how fast a given variety might raise blood sugar after a meal.
Black and green japonica rice digested more slowly than typical white rice. Slower starch breakdown means glucose enters the bloodstream more gradually, avoiding the sharp spikes associated with white rice.
The study, published in Food Research International (volume 223, article 117895), suggests this property could make pigmented rice useful in developing foods intended to support heart health, improve blood sugar management, and reduce the risk of lifestyle-related conditions such as type 2 diabetes.
How solid are these results?
The findings come with clear caveats. The digestion experiments took place in the lab, not in people, so real-world blood sugar responses remain to be confirmed in human trials. The link between FAHMFAs, LNAPEs, and health benefits also draws on earlier research in other biological systems rather than on direct measurements in rice eaters. The lipid analysis itself, however, rests on a large sample of 56 cultivars and established analytical methods.
The work forms part of a broader effort by the same group to identify unknown bioactive lipids in Japanese foods using advanced analytical techniques.
"Our research group has discovered novel bioactive lipids in Japanese dietary fish, herbal teas, and seaweeds," Gowda adds, "helping to shed light on Japan's underexplored lipid-rich food resources."
What could change for consumers?
If follow-up studies confirm the results, the findings could help shoppers compare pigmented rice varieties on more than color alone. Gowda sees two practical outcomes: better-informed consumer choices and new product development.
"People may be interested in learning about the health benefits of different pigmented rice varieties and, based on this knowledge, choosing the type that best suits their needs," he says. "We also hope our findings will support the development of new 'functional' rice products to better manage diabetes and other lifestyle-related diseases."
For now, the study offers a detailed chemical map of rice fat — and an early signal that black and green varieties deserve a closer look.
via global.hokudai.ac.jp (Original)
More from Priya Raman
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Senior reporter covering industry trends and analytics at SciBeat.
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