BackgroundThe effects of alpha-linolenic acid (ALA) on cardiovascular risk factors considerably vary between published reports. Therefore, we investigated the effects of 12-week supplementation with flaxseed oil (FO), which is a rich source of ALA, on cardiovascular risk factors such as serum small dense low-density lipoprotein (sd-LDL) concentrations.MethodsIn a randomized, double blind, crossover study, 15 subjects ingested 10 g of FO or corn oil (CO), containing 5.49 g and 0.09 g of ALA, respectively, once daily with dinner. Blood samples were collected at 0, 4 and 12 weeks, and were used for analysis of serum lipid, lipid-related proteins, serum fatty acids and serum sd-LDL cholesterol. Differences during the test period were identified using a repeated-measures analysis of variance (ANOVA) for within-group effects. Group differences were identified using paired t-test at each blood sampling time point.ResultsALA and eicosapentaenoic acid concentrations were significantly higher in the FO period at 4 and 12 weeks than in the CO period. No significant differences in docosahexaenoic acid concentrations were observed between two periods, and cholesteryl ester transfer protein and apolipoprotein B concentrations were significantly lower in the FO period than in the CO period at 12 weeks. FO supplementation was associated with a significant decrease in sd-LDL concentrations at 4 and 12 weeks, and CO supplementation had no effect. Moreover, sd-LDL concentrations were significantly lower in the FO period than in the CO period at 4 weeks. Among subjects with triglyceride (TG) concentrations of >100 mg/dl, FO supplementation markedly reduced sd-LDL concentrations at 4 and 12 weeks compared with baseline. Sd-LDL concentrations significantly differed between the periods at both 4 and 12 weeks.ConclusionThis study indicates that the FO, which is a rich source of ALA, leads to lower sd-LDL cholesterol concentrations.

We previously suggested that the consumption of natto and viscous vegetables as part of a Japanese-style meal based on white rice (WR) reduced postprandial glucose and insulin levels in healthy subjects. The aim of the present study was to assess whether a single breakfast of natto and viscous vegetables or the same breakfast consumed for 2 weeks could improve glucose control, insulin sensitivity, lipid metabolism and oxidative stress in overweight subjects with impaired glucose tolerance (IGT). A total of eleven free-living subjects with IGT followed a randomised, crossover breakfast intervention for 2 weeks. The test meal included boiled WR with natto (viscous fermented soyabeans), Japanese yam and okra. The control meal included WR with non-viscous boiled soyabeans, potatoes and broccoli. Both meals contained comparable amounts of carbohydrate, fat, protein and fibre. The test meal reduced acute glucose and insulin responses compared to the control meal in the study participants. Insulin sensitivity was assessed using the composite insulin sensitivity index (CISI) after both the test and control meal periods. The test meal resulted in improvements in CISI compared to the baseline, whereas no significant changes were observed after the control meal period. Serum levels of both total and LDL-cholesterol were assessed before and after the test meal period and found to decrease significantly. There was also a tendency towards reduced serum malondialdehyde-modified LDL and N 1 -carboxymethyllysine. No differences were observed in the measures of chronic glycaemic control. Thus, we conclude that a breakfast of natto and viscous vegetables consumed for 2 weeks improves insulin sensitivity, serum lipid and oxidative stress.Key words: Natto and viscous vegetable: Postprandial hyperglycaemia: Insulin sensitivity: Lipid metabolism: Oxidative stress Glycaemic index (GI) is an approach to classify carbohydrate foods by comparing the glycaemic effect of carbohydrate weight in individual foods (1) . In a meta-analysis of randomised controlled trials, diets with a lower GI were associated with a modest improvement in HbA1c in individuals with diabetes (2) .Postprandial hyperglycaemia is not only associated with impaired glucose tolerance (IGT) but also with hyperlipidaemia and oxidative stress, both of which increase the risk of CVD (3,4) . There is, however, considerable debate regarding the optimum and specific diet composition for preventing postprandial hyperglycaemia (5) .In Japan, many naturally viscous foods such as some types of potatoes, vegetables, mushrooms and seaweeds are cooked and eaten. They contain viscous polysaccharides such as mannan, pectin, alginic acid and galactan. Natto, a traditional and popular Japanese food made by fermenting boiled soyabeans with Bacillus natto (6) , has viscous properties. We have previously demonstrated that the consumption of natto and viscous vegetables combined with white rice (WR) suppressed postprandial hyperglycaemia and hyperinsulinaemia in healthy young subjects...

The energy values in Table 2 in the paper by Taniguchi-Fukatsu et al.(1) were incorrectly given. The correct values are given here. The authors apologise for this error.

The energy values in Table 2 in the paper by Taniguchi-Fukatsu et al.(1) were incorrectly given. The correct values are given here.The authors apologise for this error.