The stakes of the question are considerable. Insulin resistance, in which the body’s tissues respond poorly to normal circulating insulin, affects an estimated 15.5 to 46.5 percent of adults worldwide, and recent NHANES data indicate that roughly 40 percent of American adults aged 18 to 44 show the condition even in the absence of overt diabetes. Because insulin resistance sits upstream of type 2 diabetes, cardiovascular disease, hypertension, polycystic ovarian syndrome, and nonalcoholic fatty liver disease, any cheap and safe dietary tool that could improve insulin sensitivity would carry enormous public health value. That promise is precisely what drew researchers to glucomannan, whose viscosity is reportedly five times greater than that of fibers like beta-glucan and guar gum.

The new analysis, registered prospectively in the PROSPERO database, followed the PRISMA 2020 framework and searched Scopus, Web of Science, and PubMed up to March 2025. From 289 initial records, the team winnowed the literature down to eleven eligible randomized controlled trials published between 1984 and 2023, conducted in the United States, Canada, China, Slovenia, Brazil, Thailand, and Taiwan. Participants fell into three broad groups: people with type 2 diabetes, people with overweight or obesity, and people with insulin resistance syndrome. Trials ranged from as few as 11 participants to as many as 80, with durations spanning 3 to 12 weeks and glucomannan doses typically between 3,000 and 10,000 milligrams per day, sometimes delivered as enriched biscuits or gummy candy rather than capsules.

Methodologically, the review was unusually thorough for a nutrition meta-analysis. The authors used the Cochrane ROB 2 tool to grade each trial’s risk of bias, applied the GRADE framework to rate the certainty of evidence for each outcome, and ran leave-one-out sensitivity analyses to test whether any single study was propping up the pooled results. They also performed meta-regression and fractional polynomial modeling to probe whether effects scaled with dose or duration, and used Egger’s regression test and funnel plots to detect publication bias. Only one of the eleven trials, a Chinese study of obese adults, was judged to have a low overall risk of bias; three were rated high risk and the remainder raised some concerns.

The headline finding concerned fasting blood glucose. Across seven pooled effect sizes, glucomannan supplementation lowered fasting glucose by a weighted mean of 7.02 milligrams per deciliter compared with controls, a result that just crossed the threshold of statistical significance. The proposed mechanism is rooted in the fiber’s extraordinary viscosity: by forming a gel in the stomach, glucomannan delays gastric emptying and slows the absorption of carbohydrates into the bloodstream, flattening the post-meal glucose spikes that chronically stress insulin-producing cells. Fermentation of the fiber by gut microbiota, which yields short-chain fatty acids, may also contribute to improved metabolic signaling.

Yet the glucose result comes with heavy caveats that the authors themselves emphasize. The pooled estimate carried substantial heterogeneity, and removing a single trial, a Taiwanese crossover study in older adults with type 2 diabetes, caused the effect to vanish entirely. More strikingly, when the researchers reran the analysis under an alternative statistical assumption about the correlation between baseline and final measurements in crossover trials, the fasting glucose benefit lost its significance altogether. The GRADE assessment downgraded the certainty of evidence for fasting glucose to low, alongside similarly low or very low ratings for most other outcomes.

The broader cardiometabolic picture was largely one of null results. Body weight showed no significant change across nine pooled effect sizes, and neither did body mass index, body fat percentage, fasting insulin, triglycerides, total cholesterol, LDL cholesterol, or HDL cholesterol. Blood pressure outcomes were similarly flat overall, though subgroup analyses hinted at context-dependent effects: significant systolic reductions appeared in Canadian trials, crossover designs, participants over 50, and doses above 3,000 milligrams per day, while some subgroups, including male-only trials and studies in the United States, paradoxically showed increases. The authors stress that these subgroup findings, drawn from small numbers of studies, should be treated as exploratory hypothesis-generating observations rather than clinical guidance.

The dose–response analysis added a further layer of nuance. Meta-regression found no significant linear relationship between glucomannan dosage or supplementation duration and changes in weight or any lipid parameter, and fractional polynomial modeling detected no meaningful non-linear dose effects. The single exception was total cholesterol, which showed a significant non-linear relationship with intervention duration. Subgroup patterns suggested that higher doses above 3,000 milligrams per day and shorter trials of four weeks or less were associated with cholesterol reductions, but the authors caution against reading these patterns as dosing recommendations given the fragility of the underlying data.

How do these results square with earlier reviews? A 2008 meta-analysis by Sood and colleagues reported significant improvements in weight, glucose, triglycerides, and cholesterol, while more recent analyses found lipid benefits in general adult populations. The discrepancies likely reflect differences in study populations and inclusion criteria. The new review is the first to focus exclusively on adults with insulin resistance–related conditions across the spectrum, rather than narrowing to type 2 diabetes or obesity alone, and its stricter risk-of-bias standards may have tempered earlier optimism. Notably, its null weight finding echoes a 2014 analysis in people with overweight and obesity that also found no significant effect of glucomannan on body weight.

The authors conclude that glucomannan may serve as a useful adjunct for glycemic control in insulin-resistant individuals, but that its broader cardiometabolic benefits appear inconsistent and context-dependent. With significant publication bias detected for systolic blood pressure and HDL cholesterol, low-to-very-low certainty across most outcomes, and sensitivity analyses revealing instability in several pooled estimates, the evidence base remains thin. The researchers call for large, well-designed randomized trials to clarify the optimal dose, duration, and patient populations most likely to benefit, and to illuminate the mechanisms behind the fiber’s modest glucose-lowering effect. Until then, the konjac root’s reputation as a metabolic multitool appears to rest, at best, on a single fragile number.

Subject of Research: Effects of glucomannan supplementation on cardiometabolic parameters in adults with insulin resistance-related conditions

Article Title: Effects of Glucomannan on Cardiometabolic Parameters in Adults With Insulin Resistance‐Related Conditions: A Systematic Review and Dose–Response Meta‐Analysis

Article References: Jazinaki, M. S., Rafiei, H., Bahari, H., & Pahlavani, N. (2026). Effects of Glucomannan on Cardiometabolic Parameters in Adults With Insulin Resistance‐Related Conditions: A Systematic Review and Dose–Response Meta‐Analysis. Food Science & Nutrition, 14(10), Article e72460. https://doi.org/10.1002/fsn3.72460

Image Credits: AI Generated

DOI: 10.1002/fsn3.72460

Keywords: glucomannan, konjac root, insulin resistance, fasting blood glucose, meta-analysis, dietary fiber, type 2 diabetes, obesity, lipid profile, blood pressure, cardiometabolic health, systematic review

Mitochondria, the energy-producing organelles in every plant cell, carry their own small genomes, separate from the DNA in the nucleus and the chloroplast. In animals, these genomes are compact and predictable, but in plants they are famously unruly: enormous in size, structurally fluid, and prone to recombination that can reshape them from one generation to the next. That instability is precisely why plant mitochondrial genomes fascinate evolutionary biologists, and why they matter commercially, since they carry genes involved in fertility and other agronomically critical traits. Yet for all the attention paid to konjac chloroplasts and nuclear markers, the mitochondrial genomes of A. muelleri and A. krausei had never been sequenced and characterized, leaving a conspicuous gap in the genetic resources available to breeders and biologists working with the genus.

The team, led by corresponding authors Lifang Li and Lei Yu of the Yunnan Key Laboratory of Konjac Biology at Kunming University, sequenced the genomes, assembled them, and annotated their full complement of genes, then placed the two species in comparative and phylogenetic context against close relatives in the arum family. The scale of the assembled molecules alone is striking. The mitochondrial genome of A. muelleri measures 592,591 base pairs, while that of A. krausei reaches 593,535 base pairs, both arranged as circular molecules. To put those numbers in perspective, the entire human mitochondrial genome fits into fewer than 17,000 base pairs; the konjac mitochondrial genomes are roughly thirty-five times larger, a vivid illustration of how extravagantly plant mitochondrial DNA can expand over evolutionary time.

Size, however, is only the headline figure. The GC content, the proportion of the genome composed of the bases guanine and cytosine, came out at 45.90 percent for A. muelleri and 46.05 percent for A. krausei, values that sit within the range typical of flowering plant mitochondria and hint at broadly similar compositional pressures across the two species. More revealing is the gene inventory. A. muelleri carries 59 genes and A. krausei carries 62, with 55 genes shared between them. That core of 55 conserved genes represents the essential functional machinery of the mitochondrion, including the components of the respiratory chain and the ribosomal and transfer RNAs needed to build its proteins, while the differences between the two species illustrate how gene content can drift even between closely related plants.

Beneath the gene counts, the researchers dug into the fine texture of the two genomes, and it is here that the study becomes a treasure map for future work. They identified 28 high-frequency codons, codons used more often than expected, in both species, a signature of the shared translational preferences of the two mitochondrial systems. They also catalogued repetitive elements, the raw material of mitochondrial genome rearrangement: 91 dispersed repeats in A. muelleri against 125 in A. krausei, and 141 versus 148 simple sequence repeats, short tandemly repeated motifs that serve as convenient molecular markers for population studies and cultivar identification. Perhaps most intriguingly, the two species differ dramatically in one particular respect: the team found 43 RNA editing sites in A. muelleri but 220 in A. krausei, a fivefold difference that suggests the two species manage the post-transcriptional correction of their mitochondrial transcripts in notably different ways.

RNA editing is one of the stranger quirks of plant mitochondria. After a gene is transcribed from DNA into RNA, specific letters in the transcript are chemically altered, often converting a C to a U, so that the final protein differs from what the gene sequence alone would predict. Many of these edits are essential, restoring start codons or fixing amino acids that would otherwise render a protein nonfunctional. The stark contrast between 43 editing sites in one species and 220 in its close relative raises questions the study leaves open for future investigation: whether the difference reflects genuinely divergent editing machineries, different analytical sensitivities, or evolutionary turnover in the editing landscape itself. Either way, the catalogued sites provide a concrete dataset for anyone probing how konjac mitochondria maintain the integrity of their proteins.

To understand how these genomes fit into the broader evolutionary picture, the researchers compared the coding sequences of mitochondrial genomes from eight species across the Araceae family, identifying 33 shared sequences that could be aligned across the group. They then applied a classic evolutionary yardstick, the ratio of non-synonymous to synonymous substitution rates, known as Ka/Ks. Non-synonymous substitutions change the amino acid sequence of a protein, while synonymous ones do not; when the ratio of the former to the latter falls below 1, it signals that natural selection is actively weeding out protein-altering changes, preserving function. For most of the shared protein-coding genes, the Ka/Ks ratios were indeed below 1, indicating that these genes have been under purifying selection and that their protein functions have remained remarkably conserved across the family’s evolution. In other words, even as the mitochondrial genomes ballooned in size and shuffled their structures, the proteins they encode have stayed stubbornly faithful to their ancient roles.

The phylogenetic analysis, built on this comparative data, delivered a clear verdict on relationships within the genus: A. muelleri is closely related to both A. krausei and A. albus. That placement matters for more than taxonomy. Konjac breeders seeking to improve glucomannan yield, disease resistance, or tuber traits rely on knowing which species are genetically compatible and which traits can be moved between them. A well-resolved tree anchored in organellar genome data gives breeders and conservationists alike a firmer framework for choosing parents in crossing programs and for prioritizing which wild relatives to preserve as genetic resources.

The practical significance of the work extends beyond the laboratory. Amorphophallus tubers are rich in glucomannan, the soluble dietary fiber that gives konjac foods their characteristic texture and that is increasingly studied for its effects on satiety, blood sugar, and cholesterol. Yunnan Province, where the research team is based, is a center of konjac cultivation and of the wild diversity of the genus, and the study’s funding, which includes support from the Yunnan Provincial Science and Technology Department and the National Natural Science Foundation of China, reflects the region’s investment in konjac biology. Complete mitochondrial genomes add a new class of molecular markers, from the simple sequence repeats to the species-specific gene complements, that can be used to authenticate cultivars, trace germplasm, and monitor genetic diversity in breeding programs, all of which help protect a crop whose supply chains depend on a relatively narrow genetic base.

For the wider scientific community, the study is a reminder of how much fundamental biology remains hidden inside familiar crops. Two species grown and processed for centuries have only now had one of their three genomes read in full, and the reading has already surfaced surprises: genomes approaching six hundred thousand base pairs, a fivefold difference in RNA editing between close relatives, and dozens of repeats poised to drive future rearrangements. The newly assembled mitochondrial blueprints of A. muelleri and A. krausei now stand as a foundation for research into the molecular diversity, genetic evolution, and cultivation of the konjac plants, and they set the stage for the next round of questions, from the mechanisms behind their RNA editing disparity to the structural dynamics that shape the largest genomes in their cells. For a genus that quietly underpins a global food and health industry, that is a significant step out of the genomic dark.

Subject of Research: Complete mitochondrial genome assembly and comparative analysis of two Amorphophallus species

Article Title: Characterization and comparative analysis of the complete mitochondrial genomes of two Amorphophallus species (Araceae)

Article References: Shi, H., Yang, M., Qi, Y., Gao, P., Zhao, Y., Guo, J., Huang, F., Liu, J., Zhao, J., Li, L., & Yu, L. (2026). Characterization and comparative analysis of the complete mitochondrial genomes of two Amorphophallus species (Araceae). BMC Genomics. https://doi.org/10.1186/s12864-026-13344-z

Image Credits: AI Generated

DOI: 10.1186/s12864-026-13344-z

Keywords: Amorphophallus, mitochondrial genome, konjac, Araceae, genomics, RNA editing, purifying selection, phylogenetics, simple sequence repeats, glucomannan, genome assembly, plant evolution

Researchers led by Syaharuddin Alrif, Rahim Darma, Muhammad Hasbi, and Reza Asra applied a multidimensional sustainability assessment, adapted from a fisheries evaluation technique called RAPFISH, to the emerging konjac agrifood system in Sidenreng Rappang, one of the first areas in South Sulawesi to cultivate the crop commercially. Their approach, which they call RAP-Konjac, scored 27 attributes across five dimensions: economic, social, environmental, technological, and institutional. Thirty-two key informants, including twelve smallholder farmers, six local collectors, processing representatives, extension officers, academic researchers, and regional planners, provided structured scores on a five-point scale, with risk-based attributes such as export dependency reverse-coded so that higher values always meant more sustainable conditions.

The choice of study area was deliberate. Sidenreng Rappang had roughly 164 hectares of konjac under cultivation involving about 30 farmer groups and 600 farmers, and two districts, Pitu Riase and Watang Sidenreng, accounted for approximately 141 hectares, or 86 percent of the regency’s identified konjac area. Pitu Riase serves as the principal production center, while Watang Sidenreng hosts a processing factory capable of handling 40 to 70 tons of fresh tubers daily, along with aggregation, marketing, and logistics functions. Together they offered a complete window into the value chain, from field to factory gate.

The analytical machinery behind the assessment is elegant in its transparency. Multidimensional scaling transforms the ordinal attribute scores into positions within an ordination space, generating a sustainability index on a 0-to-100 scale for each dimension. Stress statistics below 0.20 and coefficients of determination above 0.80 confirmed that the ordinations fit the data well; in this study, stress values ranged from 0.145 to 0.165 and R-squared values from 0.924 to 0.933. Monte Carlo simulations, which rerun the analysis under random scoring perturbations, shifted the indices by no more than 1.39 points, meaning the results were robust to the inevitable uncertainty in expert judgment.

The headline number looks reassuring. Averaged across the five dimensions, the konjac system scored 57.41, placing it firmly in the moderately sustainable category. But the researchers’ central insight is that this aggregate figure conceals a striking asymmetry. The environmental dimension scored 67.73, the strongest of the five, while the technological dimension scored just 48.80, the only one classified as less sustainable. The 18.93-point gap between the best and worst dimensions reveals a system whose ecological foundation has developed far faster than its capacity to convert that potential into stable quality, local value addition, and resilient market participation.

The technological weakness is not a deep collapse but a near-threshold constraint, sitting just below the 50-point boundary that separates less sustainable from moderately sustainable. That positioning matters for policy, because it suggests comparatively focused improvements in farmer-level post-harvest facilities, industrial downstream processing access, certified seed systems, logistics, and innovation support could shift the dimension into a stronger category. Without such improvements, farmers remain locked into selling fresh tubers, while actors with processing facilities capture most of the value added. Nationally, the scale of this mismatch is stark: of more than 700,000 tons of konjac produced in 2020 and 2021, only about 150,000 tons met export requirements, a gap attributed to product quality, processing capacity, and compliance with market standards.

To identify where intervention would matter most, the team performed a leverage analysis, removing each attribute in turn from the ordination and measuring how much the sustainability configuration shifted. Seven attributes exceeded the high-leverage threshold of a root mean square change of 10 or more. Supply chain efficiency scored 14.90 and export market dependency 14.89, followed almost identically by agricultural extension at 14.88 and partnership effectiveness at 14.66. Seed variety conservation (11.56) and pest and disease management (11.14) anchored the environmental dimension, while industrial downstream processing technology sat exactly at the 10.00 threshold. Notably, none of the five social attributes reached even the borderline range, suggesting that social factors function as long-term enablers rather than immediate leverage points.

Combining each dimension’s sustainability status with its leverage scores produced a clear policy priority ranking: technology first, then economic restructuring, institutional strengthening, ecological consolidation, and finally inclusive rural capacity building. The economic findings carry a particular warning. Heavy dependence on a narrow export market exposes farmers and processors to external demand shocks, shifting quality standards, and buyer concentration, while fragmented supply chains raise transaction costs and weaken farmers’ bargaining positions. The researchers argue that konjac development should not be managed solely as an export-oriented commodity opportunity; transparent pricing, clearer grading standards, domestic market development, and stronger buyer-farmer coordination are equally essential. Institutional support, especially commodity-specific extension services, is the glue that holds these improvements together, because konjac cultivation, drying, slicing, grading, and quality standards all demand specialized knowledge that many farmers currently lack.

The environmental story is more nuanced than the strong 67.73 score might suggest. The assessment covered locally observable management practices, erosion risk, pest management, seed conservation, and chemical input use, but it did not quantify water use, energy consumption, or greenhouse gas emissions, so the index reflects local environmental management rather than a complete life-cycle footprint. Even so, the high leverage of seed variety conservation and pest management signals a real vulnerability: as commercial cultivation expands, reliance on selected planting materials can erode genetic diversity and intensify disease pressure. Ecological suitability, the authors conclude, is a necessary foundation for konjac development but is nowhere near sufficient on its own for a sustainable transformation.

Perhaps the most transferable lesson of the study is methodological. A system can be classified as moderately sustainable overall while remaining poorly prepared for transformation in one or more of its enabling dimensions, a condition the researchers call asymmetric sustainability. By pairing dimension-specific indices with attribute-level leverage scores, RAP-Konjac turns stakeholder knowledge into a transparent, testable order of policy attention, an approach that could be applied to other konjac-producing regions and to other emerging bio-based commodities racing from forest edge to global market. The konjac boom in South Sulawesi is real, and its ecological footing is comparatively solid, but whether smallholder farmers capture a fair share of the glucomannan economy will depend on closing the technology gap before the raw-material export pathway hardens into permanence.

Subject of Research: Multidimensional sustainability assessment of Indonesia's emerging konjac (porang) agrifood system using RAPFISH-based multidimensional scaling in Sidenreng Rappang Regency

Article Title: Multidimensional sustainability assessment of Indonesia's emerging konjac agrifood system: A case study in Sidenreng Rappang

Article References: Alrif, S., Darma, R., Hasbi, M., & Asra, R. (2026). Multidimensional sustainability assessment of Indonesia's emerging konjac agrifood system: A case study in Sidenreng Rappang. Environmental and Sustainability Indicators, 32, Article 101555. https://doi.org/10.1016/j.indic.2026.101555

Image Credits: AI Generated

DOI: 10.1016/j.indic.2026.101555

Keywords: konjac, porang, glucomannan, sustainability assessment, RAPFISH, multidimensional scaling, agrifood system, Indonesia, South Sulawesi, smallholder farmers, value chain, transition readiness