Dietary fibre has been shown to have important health implications in the prevention of risks of chronic diseases. The objective of the present study was to determine the potential health benefits of legumes as a good source of dietary fibre. Six to ten local legumes were studied as follows: cowpeas, mung beans, pole sitao, chickpeas, green peas, groundnuts, pigeon peas, kidney beans, lima beans and soyabeans. The following studies were conducted: (a) mineral availability, in vitro; (b) glycaemic index (GI) in non-diabetic and diabetic human subjects; (c) the cholesterollowering effect in human subjects with moderately raised serum cholesterol levels. The highest Fe availability among legumes was for lima beans (9·5 (SEM 0·1)) while for Zn and Ca, the highest availability was for kidney beans (49·3 (SEM 4·5)) and pigeon peas (75·1 (SEM 7·1)), respectively. Groundnuts have the lowest Fe (1·3 (SEM 1·1)), Zn (7·9 (SEM 1·3)) and Ca (14·6 (SEM 2·8)) availability. Legumes are low-GI foods (, 55), ranging from 6 (chickpeas) to 13 (mung beans). Kidney beans showed significant reductions for both total (6 %) and LDL-cholesterol (9 %), and groundnuts for total cholesterol (7 %; P,0·05). We conclude that mineral availability from legumes differs and may be attributed to their mineral content, mineral -mineral interaction and from their phytic and tannic acid content; legumes are considered low-GI foods and have shown potential hypocholesterolaemic effects. The above studies can be a scientific basis for considering legumes as functional foods.

No abstract

A combination of dietary and host-related factors determines iron and zinc absorption, and several in vitro methods have been developed as preliminary screening tools for assessing bioavailability. An expert committee has reviewed evidence for their usefulness and reached a consensus. Dialyzability (with and without simulated digestion) gives some useful information but cannot predict the correct magnitude of response and may sometimes predict the wrong direction of response. Caco-2 cell systems (with and without simulated digestion) have been developed for iron availability, but the magnitude of different effects does not always agree with results obtained in human volunteers, and the data for zinc are too limited to draw conclusions about the validity of the method. Caco-2 methodologies vary significantly between laboratories and require experienced technicians and good quality cell culture facilities to obtain reproducible results. Algorithms can provide semi-quantitative information enabling diets to be classified as high, moderate, or low bioavailability. While in vitro methods can be used to generate ideas and develop hypotheses, they cannot be used alone for important decisions concerning food fortification policy, selection of varieties for plant breeding programs, or for new product development in the food industry. Ultimately human studies are required for such determinations.

Brown rice is a good source of dietary fibre (DF) and contains higher vitamins/minerals than milled rice. The study determined the effect of amylose content (AC) and DF on glucose response (GR) from different varieties of milled and brown rice. Milled and brown rice were used as test foods. They were fed to 9-10 human volunteers containing 50 g available carbohydrate after an overnight fast. GR and the glycemic index (GI) were determined. Results found that Sinandomeng with the lowest AC had a high GI = 75, while PSBRc10 with the highest AC had a low GI = 50. Sinandomeng with a low DF had GI = 75, while its brown rice had GI = 55. Brown rice (IR64) with 23% AC and DF of 2.5 g/100 g had low GI = 51. In conclusion, the GR and GI of the different varieties of cooked milled and brown rice varied depending on its AC and DF contents.

Summary Reliably generating rice varieties with low glycaemic index ( GI ) is an important nutritional intervention given the high rates of Type II diabetes incidences in Asia where rice is staple diet. We integrated a genome‐wide association study ( GWAS ) with a transcriptome‐wide association study ( TWAS ) to determine the genetic basis of the GI in rice. GWAS utilized 305 re‐sequenced diverse indica panel comprising ~2.4 million single nucleotide polymorphisms ( SNP s) enriched in genic regions. A novel association signal was detected at a synonymous SNP in exon 2 of LOC _Os05g03600 for intermediate‐to‐high GI phenotypic variation. Another major hotspot region was predicted for contributing intermediate‐to‐high GI variation, involves 26 genes on chromosome 6 ( GI 6.1). These set of genes included GBSSI , two hydrolase genes, genes involved in signalling and chromatin modification. The TWAS and methylome sequencing data revealed cis ‐acting functionally relevant genetic variants with differential methylation patterns in the hot spot GI 6.1 region, narrowing the target to 13 genes. Conversely, the promoter region of GBSSI and its alternative splicing allele (G allele of Wx a ) explained the intermediate‐to‐high GI variation. A SNP (C˃T) at exon‐10 was also highlighted in the preceding analyses to influence final viscosity ( FV ) , which is independent of amylose content/ GI . The low GI line with GC haplotype confirmed soft texture, while other two low GI lines with GT haplotype were characterized as hard and cohesive. The low GI lines were further confirmed through clinical in vivo studies. Gene regulatory network analysis highlighted the role of the non‐starch polysaccharide pathway in lowering GI .