Fruit form Influences Postprandial Glycemic Response in Elderly and Young Adults.

OBJECTIVES: This study compared the effects of consuming different forms (bite size, puree) and two fruit types (guava, papaya) on glycemic response (GR) in elderly and young adults. DESIGN: This study was conducted using a randomized, crossover design. PARTICIPANTS: Nineteen healthy participants (9 elderly, 10 young adults) were recruited from the general public in Singapore. INTERVENTION: Participants consumed glucose (reference food) on three occasions and test fruits (guava bites, guava puree, papaya bites, and papaya puree) on one occasion each. MEASUREMENTS: Blood glucose was analyzed prior to consuming the test food, at 15, 30, 45, 60, 90 and 120 minutes after food consumption. RESULTS: The incremental area under the blood glucose response curve (iAUC) over 120 minutes for all the treatments was significantly lower than glucose (all P < 0.001). All fruit forms and types studied were low glycemic index (GI) (guava bites: 29; papaya bites: 38; papaya puree: 42; guava puree: 47), albeit a significant difference in GI between the treatments was found (P = 0.003). Elderly exhibited significantly greater GR than young participants (P = 0.019). CONCLUSION: Although fruit form influences GR in the elderly and young adults, all fruit types and forms studied were found to be low GI. This study indicates that fruits are a valuable source of nutrient irrespective of the form of delivery in elderly and young adults. This study was registered at www.anzctr.org.au as ACTRN12614000655640.

Central adiposity-induced plasma-free amino acid alterations are associated with increased insulin resistance in healthy Singaporean adults.

BACKGROUND/OBJECTIVES: Recent metabolomics technique reveals a plasma-free amino acid (PFAA)-based metabolite signature that is suggestive of altered PFAAs being an early manifestation of obesity-related insulin resistance. However, the PFAA profiles within non-obese, but more insulin-resistant Asians are not well researched. Compared with Caucasians, Asian populations have more central adiposity, which is generally regarded as metabolically more adverse, but the underlying mechanisms remain unclear. In the present study, we examined whether PFAA profiling was at least one important factor mediating central adiposity and insulin resistance, and aid in cardiovascular risk assessment in healthy Asians with normal body weight. SUBJECT/METHODS: This was a cross-sectional study. A total of 190 healthy men (n=87 with a mean±s.d. body mass index (BMI) of 23.5±3.5 kg/m2) and women (n=103 with a mean±s.d. BMI of 21.4±3.7 kg/m2) residing in Singapore took part in this study. PFAA levels were measured by using an amino acid analyzer. Basic anthropometric measurements, fasting blood glucose, fasting serum insulin and lipid profiles were obtained using standard protocols. RESULTS: Seven out of 18 amino acids were significantly correlated with measures of obesity (for example, waist circumference; waist-to-hip ratio and BMI) in current participants. Among them, the plasma concentrations of five amino acids, including Phe, Tyr, Met, Ala and His were positively associated with waist-to-hip ratio. With the exception of His, which had no association with insulin resistance, Phe, Tyr, Met and Ala were significantly associated with hyperinsulinemia and insulin resistance (P<0.05). In contrast, no associations were observed between circulating BCAAs (that is, Val, Leu, Ile), measures of obesity and insulin resistance. However, significant inverse associations were observed between BCAAs and total cholesterol and high-density lipoprotein. CONCLUSIONS: We found that central adiposity was associated with alterations of specific amino acids. As a result, PFAAs may serve as metabolite predictors of hyperglycemia, hyperinsulinemia and dyslipidemia in healthy participants.

Effects of non-nutritive (artificial vs natural) sweeteners on 24-h glucose profiles.

Replacing nutritive sweetener with non-nutritive sweeteners (NNS) has the potential to improve glycaemic control. The objective of this study was to investigate the effects of consuming artificial NNS (that is, aspartame), natural NNS (that is, monk fruit and stevia), and sucrose-sweetened beverages on 24-h glucose profiles. Ten healthy males took part in this randomised, crossover study with the following four treatments: aspartame-, monk fruit-, stevia-, and sucrose- (65 g) sweetened beverages. Participants were asked to consume the test beverage as a preload mid-morning. Medtronic iPro2 continuous glucose monitoring system was used to measure mean 24-h glucose, incremental area under the curve (iAUC) and total area under the curve (AUC) for glucose, and 24-h glycaemic variability. Overall no significant differences were found in mean 24-h glucose, iAUC and total AUC for glucose, and 24-h glycaemic variability between the four test beverages. Twenty-four-hour glucose profiles did not differ between beverages sweetened with non-nutritive (artificial vs natural) and nutritive sweeteners. The simple exchange of a single serving of sucrose-sweetened beverage with NNS over a day appears to have minimal effect on 24-h glucose profiles in healthy males.

Effects of aspartame-, monk fruit-, stevia- and sucrose-sweetened beverages on postprandial glucose, insulin and energy intake.

BACKGROUND: Substituting sweeteners with non-nutritive sweeteners (NNS) may aid in glycaemic control and body weight management. Limited studies have investigated energy compensation, glycaemic and insulinaemic responses to artificial and natural NNS. OBJECTIVES: This study compared the effects of consuming NNS (artificial versus natural) and sucrose (65 g) on energy intake, blood glucose and insulin responses. METHODS: Thirty healthy male subjects took part in this randomised, crossover study with four treatments: aspartame-, monk fruit-, stevia- and sucrose-sweetened beverages. On each test day, participants were asked to consume a standardised breakfast in the morning, and they were provided with test beverage as a preload in mid-morning and ad libitum lunch was provided an hour after test beverage consumption. Blood glucose and insulin concentrations were measured every 15 min within the first hour of preload consumption and every 30 min for the subsequent 2 h. Participants left the study site 3 h after preload consumption and completed a food diary for the rest of the day. RESULTS: Ad libitum lunch intake was significantly higher for the NNS treatments compared with sucrose (P=0.010). The energy 'saved' from replacing sucrose with NNS was fully compensated for at subsequent meals; hence, no difference in total daily energy intake was found between the treatments (P=0.831). The sucrose-sweetened beverage led to large spikes in blood glucose and insulin responses within the first hour, whereas these responses were higher for all three NNS beverages following the test lunch. Thus, there were no differences in total area under the curve (AUC) for glucose (P=0.960) and insulin (P=0.216) over 3 h between the four test beverages. CONCLUSIONS: The consumption of calorie-free beverages sweetened with artificial and natural NNS have minimal influences on total daily energy intake, postprandial glucose and insulin compared with a sucrose-sweetened beverage.

Current guidelines for nut consumption are achievable and sustainable: a hazelnut intervention.

Nuts are known for their hypocholesterolaemic properties; however, to achieve optimal health benefits, nuts must be consumed regularly and in sufficient quantity. It is therefore important to assess the acceptability of regular consumption of nuts. The present study examined the long-term effects of hazelnut consumption in three different forms on 'desire to consume' and 'overall liking'. A total of forty-eight participants took part in this randomised cross-over study with three dietary phases of 4 weeks: 30 g/d of whole, sliced and ground hazelnuts. 'Overall liking' was measured in a three-stage design: a pre- and post-exposure tasting session and daily evaluation over the exposure period. 'Desire to consume' hazelnuts was measured during the exposure period only. Ratings were measured on a 150 mm visual analogue scale. Mean ratings of 'desire to consume' were 92 (SD 35) mm for ground, 108 (SD 33) mm for sliced and 116 (SD 30) mm for whole hazelnuts. For 'overall liking', the mean ratings were 101 (SD 29) mm for ground, 110 (SD 32) mm for sliced and 118 (SD 30) mm for whole hazelnuts. Ground hazelnuts had significantly lower ratings than both sliced (P ≤ 0·034) and whole hazelnuts (P < 0·001), with no difference in ratings between sliced and whole hazelnuts (P ≥ 0·125). For each form of nut, ratings of 'overall liking' and 'desire to consume' were stable over the exposure period, indicating that not only did the participants like the nuts, but also they wished to continue eating them. Therefore, the guideline to consume nuts on a regular basis appears to be a sustainable behaviour to reduce CVD.

Effects of different forms of hazelnuts on blood lipids and α-tocopherol concentrations in mildly hypercholesterolemic individuals.

BACKGROUND/OBJECTIVES: Diets high in nuts reduce cholesterol, probably due to their favorable lipid profile and other bioactive substances. However, the physical form of the nut may be important as the cell wall of intact nuts may limit the hypocholesterolemic effect of nuts by reducing lipid bioavailability. Therefore, we investigated the effects on blood lipids of incorporating three different forms of hazelnuts (ground, sliced and whole) into the usual diet. SUBJECTS/METHODS: In a randomized crossover study with three phases, 48 mildly hypercholesterolemic participants were asked to consume 30 g of ground, sliced or whole hazelnuts for 4 weeks. Body weight, plasma total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triacylglycerol (TAG), apolipoprotein (apo) A1, apo B100 and α-tocopherol were measured at baseline and at the end of each dietary phase. RESULTS: There were no significant differences in any outcome variable between the different forms of nuts (all P ≥ 0.159). However, compared with baseline, mean values at the end of each hazelnut intervention were significantly higher for HDL-C (P = 0.023) and α-tocopherol (P = 0.005), and significantly lower for TC (P < 0.001), LDL-C (P < 0.001), TC:HDL-C ratio (P <0 .001), apo B100 (P = 0.002) and apo B100:apo A1 ratio (P < 0.001), with no significant difference in body weight (P = 0.813). CONCLUSIONS: The ingestion of three different forms of hazelnuts equally improved the lipoprotein profile and α-tocopherol concentrations in mildly hypercholesterolemic individuals. Hazelnuts can therefore be incorporated into the usual diet as a means of reducing cardiovascular disease risk.