Recent genome-wide association studies (GWAS) on the dietary habits of the Japanese population have shown that an effect rs671 allele was inversely associated with fish consumption, whereas it was directly associated with coffee consumption. Although meat is a major source of protein and fat in the diet, whether genetic factors that influence meat-eating habits in healthy populations are unknown. This study aimed to conduct a GWAS to find genetic variations that affect meat consumption in a Japanese population. We analysed GWAS data using 14 076 participants from the Japan Multi-Institutional Collaborative Cohort (J-MICC) study. We used a semi-quantitative food frequency questionnaire to estimate food intake that was validated previously. Association of the imputed variants with total meat consumption per 1000 kcal energy was performed by linear regression analysis with adjustments for age, sex, and principal component analysis components 1–10. We found that no genetic variant, including rs671, was associated with meat consumption. The previously reported single nucleotide polymorphisms that were associated with meat consumption in samples of European ancestry could not be replicated in our J-MICC data. In conclusion, significant genetic factors that affect meat consumption were not observed in a Japanese population.

Differences in individual eating habits may be influenced by genetic factors, in addition to cultural, social or environmental factors. Previous studies suggested that genetic variants within sweet taste receptor genes family were associated with sweet taste perception and the intake of sweet foods. The aim of this study was to conduct a genome-wide association study (GWAS) to find genetic variations that affect confection consumption in a Japanese population. We analysed GWAS data on confection consumption using 14 073 participants from the Japan Multi-Institutional Collaborative Cohort study. We used a semi-quantitative FFQ to estimate food intake that was validated previously. Association of the imputed variants with confection consumption was performed by linear regression analysis with adjustments for age, sex, total energy intake and principal component analysis components 1–3. Furthermore, the analysis was repeated adjusting for alcohol intake (g/d) in addition to the above-described variables. We found 418 SNP located in 12q24 that were associated with confection consumption. SNP with the ten lowest P-values were located on nine genes including at the BRAP, ACAD10 and aldehyde dehydrogenase 2 regions on 12q24.12-13. After adjustment for alcohol intake, no variant was associated with confections intake with genome-wide significance. In conclusion, we found a significant number of SNP located on 12q24 genes that were associated with confections intake before adjustment for alcohol intake. However, all of them lost statistical significance after adjustment for alcohol intake.

We evaluated the effects of long-term daily cows' milk (CM) administration on insulin resistance induced by a high-sucrose diet. F344 rats, aged 3 weeks, were divided into two groups according to diet (dextrin-fed v. sucrose-fed). These groups were further divided into two groups receiving either CM or artificial milk (AM; isoenergetic emulsion of egg white protein, maltose, lard and minerals). Rats were fed a sucrose- or dextrin-based diet for 7 weeks and orally administered CM or AM at 25 ml/kg following an 8 h fast on a daily basis. Insulin sensitivity was evaluated via postprandial changes in serum glucose and insulin, oral glucose tolerance tests, and fasting serum insulin and fructosamine concentrations. The sucrose-fed rats showed an overall decrease in insulin sensitivity, but postprandial insulin levels were lower in the CM-treated subgroup than in the AM-treated subgroup. Peak serum glucose and insulin concentrations were highest in the sucrose-fed rats, but CM administration reduced peak glucose and insulin values in comparison with AM administration. By area under the curve analysis, insulin levels after feeding and glucose loads were significantly lower in the CM-treated groups than in the AM-treated groups. The CM-treated groups also demonstrated lower fasting insulin and fructosamine levels than the AM-treated groups. Improved insulin sensitivity due to CM administration seemed to be associated with reduced duodenal GLUT2 mRNA levels and increased propionate production within the caecum.

Equol, a derivative of daidzein produced by enterobacteria, has greater activity as a phyto-oestrogen compared with daidzein. Difructose anhydride III (DFAIII) is a newly manufactured non-digestible disaccharide with unique fermentation properties. The present study evaluated the prebiotic effects of DFAIII on equol production and on plasma cholesterol concentrations related to the changes in equol production. We compared plasma equol concentrations at 10.00 and 18.00 hours and faecal isoflavone excretion in three groups of seven rats (male Wistar-ST strain, 6 weeks old) fed a basal diet or a DFAIII or fructooligosaccharide (15/g diet) diet containing 1g soya isoflavone/g diet for 20d. Equol concentrations in the DFAIII group were higher than in the control and fructooligosaccharides groups, especially in the later phase of the light period (18.00 hours) throughout the experiment. Daizein and genistein concentrations did not change between the diet groups. The faecal ratios of equol:daidzein were very high in all groups, but the ratios were higher in the DFAIII group than the control and fructooligosaccharide groups on day 3, and this tendency continued throughout the experiment. On day 20, the plasma total cholesterol concentration was lowest in the DFAIII group. Additionally, the cholesterol concentrations were inversely correlated to plasma equol concentration in all the rats. In conclusion, DFAIII efficiently enhanced plasma equol concentrations, which may be associated with an increase in equol production and a decrease in equol degradation by enterobacteria. Higher plasma equol concentrations may contribute to the hypocholesterolaemic effect of DFAIII feeding.

As the physiological roles of dietary lecithin have not yet been clearly defined, we examined the effects of lecithin on lipid absorption in male Wistar rats with a mesenteric lymph cannula. Lymphatic absorption was observed after the infusion of 1 ml emulsion containing 100 mg test oil emulsified with sodium taurocholate (10 g/l) in three separate experiments. Test oils (100 mg) were: soyabean oil (triacylglycerol (TG) source, SO) and soyabean oil + lecithin (75 mg soyabean oil+25 mg lecithin, LE) in Expt 1; SO, LE or soyabean oil + lysolecithin (75 mg soyabean oil plus 25 mg lysolecithin, LY) in Expt 2; hydrolysed soyabean oil (HSO) or HSO+lysolecithin (75 mg HSO+25 mg lysolecithin, HLY) in Expt 3. After LE and LY infusions, lymph flow and the lymphatic output of TG was higher than after SO infusion at 0-30 min and 0-90 min respectively (Expts 1 and 2). Lecithin-induced increases in lymph TG output remained constant when HSO was infused (Expt 3). There were no differences in the TG:phospholipid ratio in the lymph after infusion among the groups; nevertheless, the lymphatic output of TG was much higher after infusion with LE than with SO. Fatty acid was released more efficiently from SO than from LE and LY by in vitro digestion with rat bile–pancreatic juice. These present results demonstrate that a TG emulsion containing soyabean lecithin or its hydrolysates promote lymphatic TG output and suggest that the increases in TG absorption do not depend on TG digestion.