Cognitive performance, mood and satiety following ingestion of beverages imparting different glycaemic responses: a randomised double-blind crossover trial.

BACKGROUND/OBJECTIVE: The relationship between postprandial glycaemic responses and cognitive performance, mood and satiety are inconsistent. The objective of this study is to compare the effects of different glycaemic responses, induced by beverages with different glycaemic index (GI) (sucrose and isomaltulose), and a non-glycaemic control (sucralose), on cognition, mood and satiety. SUBJECTS/METHODS: In this double-blinded, randomised crossover trial, healthy adults (n = 55) received sucrose (GI 65), isomaltulose (GI 32) and sucralose (non-caloric negative control) drinks on separate occasions. The Complex Figure test, the Word Recall test, Trail Making Test Part B and the Stroop test were administered 60 min after beverages ingestion. Mood and satiety were tested along with cognitive performance. RESULTS: Comparing between isomaltulose and sucrose, there were no significant differences in the mean (95% CI) for the following: Complex Figure: immediate recall -0.6 (-1.7, 0.5), delayed recall -0.8 (-1.9, 0.3); Word recall: immediate recall 0.2 (-0.7, 1.1), delayed recall 0.5 (-0.4, 1.4); Trail Making: completing time -2.4 (-7.5, 2.7) s; Stroop: time used for correct congruent responses -9 (-31, 14) ms and correct incongruent responses -18 (-42, 6) ms. No differences among beverages were found in the mood and satiety scores with exception that participants felt more energetic 60 min after isomaltulose ingestion (p = 0.028 for difference with sucrose) and hungrier 30 min after isomaltulose ingestion (p = 0.036 for difference with sucrose; p = 0.022 for difference with sucralose). CONCLUSION: Under these study conditions there is no convincing evidence for an effect of glycaemic response on cognitive performance, mood or satiety.

Macronutrients and Human Health for the 21st Century.

Fat, protein and carbohydrate are essential macronutrients. Various organisations have made recommendations as to the energy contribution that each of these components makes to our overall diet. The extent of food refining and the ability of food systems to support future populations may also impact on how macronutrients contribute to our diet. In this Special Issue, we are calling for manuscripts from all disciplines to provide a broad-ranging discussion on macronutrients and health from personal, public and planetary perspectives.

The effect on satiety of ingesting isosweet and isoenergetic sucrose- and isomaltulose-sweetened beverages: a randomised crossover trial.

Generating feelings of satiety may be important in maintaining weight control. It has been hypothesised that the circulating concentration of glucose is a major determinant of satiety, yet the relationship between postprandial glycaemia and satiety is inconclusive. Our aim was to assess satiety following ingestion of beverages differing in glycaemic index (GI) containing either 50 g of sucrose (GI 65) or isomaltulose (PalatinoseTM) (GI 32). The beverages were matched for sweetness using a triangle sensory test. Seventy-seven participants were randomised to the order in which they received each beverage, 2 weeks apart. A standard lunch was given at 12.00 hours. Satiety was measured using 100-mm visual analogue scales (VAS) administered at 14.00 hours (baseline) and at 30, 60, 90, 120, 150 and 180 min after ingesting the beverage. Weighed diet records were kept from 17.00 to 24.00 hours. Mean differences for isomaltulose compared with sucrose AUC VAS were 'How hungry do you feel?' 109 (95 % CI -443, 661) mm × min; 'How satisfied do you feel?' 29 (95 % CI -569, 627) mm × min; 'How full do you feel?' -91 (95 % CI -725, 544) mm × min and 'How much do you think you can eat?' 300 (95 % CI -318, 919) mm × min. There was no between-treatment difference in satiety question responses or in dietary energy intake -291 (95 % CI -845, 267) kJ over the remainder of the day. In this experiment, feelings of satiety were independent of the GI of the test beverages. Any differences in satiety found between foods chosen on the basis of GI could be attributable to food properties other than the glycaemic-inducing potential of the food.

The effect of postprandial glycaemia on cognitive function: a randomised crossover trial.

The effect on cognitive test scores of generating differences in postprandial glycaemia using test foods or beverages has been inconsistent. Methodological issues may account for some of the variable results requiring further investigation using strong study designs into the relationship between glycaemia and cognitive functioning. The objective of this study was to determine the effects of postprandial glycaemia on cognitive function by examining cognition after consumption of foods that differ only by the rate of digestion of available carbohydrate in a population of young adults. In a double-blind, randomised, crossover trial, sixty-five participants received trifle sweetened either with a higher-glycaemic index (GI) sugar (sucrose; GI 65) or a lower-GI sugar (isomaltulose; GI 34). Cognitive tests were completed prior to trifle consumption, and 60 and 120 min after. There was no between-trifle difference at 60 min in performance on free word recall (0·0 (95 % CI -0·6, 0·5)), short delay word recall (0·0 (95 % CI -0·5, 0·5)), long delay word recall (0·0 (95 % CI -0·6, 0·6)), letter-number sequence recall (0·3 (95 % CI - 0·2, 0·7)) and visuo-spatial recall (-0·2 (95 % CI -0·6, 0·2)) tests. At 120 min, no difference was detected in any of these tests. The participants performed 7·7 (95 % CI 0·5,14·9) s faster in Reitan's trail-making test B 60 min after the higher-GI trifle than the lower-GI trifle (P = 0·037). Our findings of a null effect on memory are generally consistent with other works in which blinding and robust control for confounding have been used.

Development and Evaluation of an Internet-Based Diabetes Nutrition Education Resource.

Nutritional education for pre- and type 2 diabetes empowers individuals to make positive dietary and lifestyle choices. As the world migrates to digital devices, opportunities arise for education resources to reach a broad spectrum of society. This study aimed to develop and test the effectiveness of an electronic nutritional education resource for people with pre- and type 2 diabetes within the multi-ethnic New Zealand population. A needs assessment was conducted via ethnic-specific discussion groups (n = 29), followed by a population-based online survey (n = 448). An educational resource, including an educational video and pre- and post-questionnaires, was developed and tested online among 156 participants (17 with pre- and type 2 diabetes, 118 interested lay public and 21 health professionals). There was a strong desire to learn nutrition through simple, visual, practical, and culturally appropriate online educational resources. After interacting with the educational resource, the accuracy of identifying foods that increase blood glucose concentration improved by 17.4% (p = 0.013) in people with pre- and type 2 diabetes, 12.8% (p = 0.003) in health professionals, and 16.3% (p < 0.001) in interested lay public. There was an improvement among ethnic minority participants of 14.1% (p = 0.003). Most participants expressed intentions to make positive dietary and lifestyle choices. The electronic nutrition education resource was found to be an effective means for delivering education. It has potential to bridge the gap between the limited supply of healthcare resources and the increasing demand for diabetes nutrition education.

Subjective Satiety Following Meals Incorporating Rice, Pasta and Potato.

The satiating capacity of carbohydrate staples eaten alone is dependent upon the energy density of the food but relative satiety when starchy staples are incorporated into mixed meals is uncertain. Our aim was to assess the satiating effects of three carbohydrate staples; jasmine rice, penne pasta, and Agria potato, each consumed within a standard mixed meal. Cooked portions of each staple containing 45 g carbohydrate were combined with 200 g of meat sauce and 200 g of mixed vegetables in three mixed meals. The quantities of staple providing 45 g carbohydrate were: Rice, 142 g; pasta, 138 g and potato 337 g. Participants (n = 14) consumed each of the mixed meals in random order on separate days. Satiety was assessed with using visual analogue scales at baseline and for 3 h post meal. In an area-under-the-curve comparison, participants felt less hungry (mean (SD)) following potato 263 (230) than following rice 374 (237) or pasta 444 (254) mm∙min, and felt fuller, more satisfied, and wanted to eat less following the potato compared with the rice and pasta meals (p for all <0.01). The superior satiating effect of potato compared with rice and pasta in a mixed meal was consistent with its lower energy density.

The Timing of Activity after Eating Affects the Glycaemic Response of Healthy Adults: A Randomised Controlled Trial.

There is scant information on how a time lag between the cessation of eating and commencement of physical activity affects postprandial glycaemia. Starting at baseline (t = 0), participants ingested white bread containing 50 g of available carbohydrates within 10 min. Using two crossover conditions, we tested the effect over 2 h on postprandial glycaemia of participants undertaking light activity at 15 or 45 min following baseline and compared it with a sedentary control condition. The activity involved cycling on a stationary ergometer for 10 min at 40 revolutions per min with zero resistance. Seventy-eight healthy adults were randomized to the 15 or 45 min activity arm and then randomised to the order in which they undertook the active and sedentary conditions. Cycling 45 min after baseline changed the course of the blood glucose response (likelihood ratio chi square = 31.47, p < 0.01) and reduced mean blood glucose by 0.44 mmol/L (95% confidence interval 0.14 to 0.74) at 60 min when compared with the sedentary control. No differences in postprandial blood glucose response were observed when cycling started 15 min after baseline compared with the sedentary control. Undertaking activity after waiting for 30 min following eating might be optimal in modifying the glycaemic response.

The Comparative Effect on Satiety and Subsequent Energy Intake of Ingesting Sucrose or Isomaltulose Sweetened Trifle: A Randomized Crossover Trial.

The effect that blood glucose concentration has on feelings of satiety is unclear. Our aims were to assess satiety and subsequent energy intake following the ingestion of trifle sweetened with sucrose or isomaltulose whilst measuring plasma glucose concentration to confirm glycemic differences between trifles. Seventy-seven healthy adults participated in a double-blind crossover trial where trifle sweetened with sucrose or isomaltulose was consumed on separate days with a two-week washout. Blood was sampled at the baseline, 1 and 2 h postprandially, and satiety assessed using visual analogue scales (VAS). Weighed diet records were taken on test days. A statistically significant difference in blood glucose concentration between trifles was found at 60 min following consumption, with the isomaltulose trifle having a 0.69 mmol/L (95% confidence interval: -1.07, -0.31) lower concentration when compared with the sucrose trifle. Mean satiety response by area-under-the-curve (AUC) was not significantly different between trifles. Mean (SD) appetite scores for the sucrose and isomaltulose trifles were 4493 (2393) and 4527 (2590) mm·min, respectively, with a between trifle difference of -9 (95% CI: -589, 572) mm·min. Mean (SD) energy intake for the remainder of the day following trifle consumption was 3894 kJ (1950 kJ) and 3530 kJ (1926 kJ) after the sucrose and isomaltulose trifles, respectively, and was not significantly different (p = 0.133). The differing glycemic response to trifle was not related to satiety or to subsequent energy intake.

Relevance of the Glycemic Index and Glycemic Load for Body Weight, Diabetes, and Cardiovascular Disease.

Despite initial enthusiasm, the relationship between glycemic index (GI) and glycemic response (GR) and disease prevention remains unclear. This review examines evidence from randomized, controlled trials and observational studies in humans for short-term (e.g., satiety) and long-term (e.g., weight, cardiovascular disease, and type 2 diabetes) health effects associated with different types of GI diets. A systematic PubMed search was conducted of studies published between 2006 and 2018 with key words glycemic index, glycemic load, diabetes, cardiovascular disease, body weight, satiety, and obesity. Criteria for inclusion for observational studies and randomized intervention studies were set. The search yielded 445 articles, of which 73 met inclusion criteria. Results suggest an equivocal relationship between GI/GR and disease outcome. The strongest intervention studies typically find little relationship among GI/GR and physiological measures of disease risk. Even for observational studies, the relationship between GI/GR and disease outcomes is limited. Thus, it is unlikely that the GI of a food or diet is linked to disease risk or health outcomes. Other measures of dietary quality, such as fiber or whole grains may be more likely to predict health outcomes. Interest in food patterns as predictors of health benefits may be more fruitful for research to inform dietary guidance.

Carbohydrate Knowledge and Expectations of Nutritional Support among Five Ethnic Groups Living in New Zealand with Pre- and Type 2 Diabetes: A Qualitative Study.

Despite availability of diabetes and nutrition information for people with pre- and type 2 diabetes, the uptake and understanding of these resources may differ among ethnic groups. Our objective was to explore dietary knowledge and diabetes experiences amongst Maori, European, Pacific Island, Indian and East Asian people living in New Zealand with a focus on carbohydrate-containing foods. A registered diabetes dietitian led ethnic-specific discussions in groups involving 29 people with pre- or type 2 diabetes. Discussions were audio-recorded, fully transcribed and coded independently by two investigators. Themes were developed using deductive and inductive techniques. Five themes emerged: knowledge, concerns, achievements, simplicity and self-determination. Nutritional knowledge was lacking and a greater awareness of trustworthy dietary resources was needed. There were concerns about diabetes complications and appropriate carbohydrate-containing foods and portions. Contrary to this, people felt proud when achieving dietary goals and grateful for support from health care providers and family. Participants were willing to engage in self-care if advice from health professionals was given in plain language, and in a culturally appropriate manner. Given the desire to take an active role in diabetes self-management and willingness to use electronic devices, an ethnic-specific nutrition education resource could be a valuable tool.

Postprandial Glycaemic, Hormonal and Satiety Responses to Rice and Kiwifruit Preloads in Chinese Adults: A Randomised Controlled Crossover Trial.

Controlling postprandial glycaemia helps to prevent and manage non-communicable diseases. One strategy in controlling glycaemia may be to consume meals in two parts; a preload, followed by the remainder of the meal. Our aim was to test preloading a rice meal given for breakfast and lunch on different days, either by splitting the meal (rice preload followed by rice meal) or by using kiwifruit as a preload compared with consuming the rice meal in one sitting. Primary outcomes were glycaemic and insulinaemic responses with secondary outcomes of other hormonal responses, subjective satiety, and subsequent energy intake. Following breakfast, postprandial glycaemic peak concentration was 0.9 (95% CI: 0.2, 1.6) mmol/L lower for the kiwifruit preload compared with the rice meal eaten in one sitting. Following lunch, glycaemic peak concentrations were 1.0 (0.7, 1.4) and 1.1 (0.5, 1.7) mmol/L lower for the rice-split and kiwifruit preload compared with the rice meal alone, respectively. Postprandial insulinaemia area-under-the-curve was 1385 (87, 2684) mU/L·min less for the kiwifruit preload compared with the rice-split. There were no differences among treatments for subsequent energy intake. Meal splitting is useful for lowering postprandial glycaemia, and replacing part of a meal with kiwifruit may help with insulin efficiency without detriment to subsequent energy intake.

The effects of apples and apple juice on acute plasma uric acid concentration: a randomized controlled trial.

Background: The consumption of large amounts of fructose from added sugars results in the hepatic production and export of uric acid into the circulation. Objective: Our aim was to test whether fructose present in fruit is of sufficient quantity or in a form that will increase uric acid concentration. Design: Seventy-three participants were randomly assigned to 1 of 3 groups to ingest small (205 g) and large (410 g) servings of apple segments, small (170 mL) and large (340 mL) servings of apple juice, or a glucose and a fructose control beverage. Within each group, participants ingested both treatments in a crossover design. The fructose control and the large servings of apple and juice contained 26.7 g fructose. Test foods were ingested within 10 min. Blood samples were taken at baseline and at 30 and 60 min after intake. Results: Plasma uric acid concentrations increased after the intake of all fructose-containing treatments and decreased after the glucose beverage. The mean (95% CI) increase in uric acid at 30 min was 15 µmol/L (10, 21 µmol/L) for the fructose control and 19 µmol/L (8, 30 µmol/L) and 17 µmol/L (9, 24 µmol/L) for the large servings of apple and apple juice, respectively. There was no difference in change in uric acid between baseline and 30 min when comparing the apple (3 µmol/L; 95% CI: -8, 14 µmol/L) and apple juice (-7 µmol/L; 95% CI: -18, 5 µmol/L) with the fructose control. Blood pressure taken 70 min after ingestion was unaffected by any treatment (P > 0.05). There was no difference in change in satiety scores between the fructose and glucose control beverages (P > 0.05). Participants felt more satiated 30 min after ingesting whole apple than after apple juice. The glycemic response reflected the amount of glucose in each treatment. Conclusions: The body acutely responds to fructose regardless of source. Longer-term studies are required to assess how small and transient increases in plasma uric acid contribute to health. This trial was registered with the Australian New Zealand Clinical Trials Registry at https://www.anzctr.org.au/trial/registration/trialreview.aspx?id=367974 as ACTRN12615000215527.

Glycated albumin is stable in plasma when exposed to common laboratory conditions and comparable when drawn from venous or capillary sites.

BACKGROUND: Circulating glycated albumin is a marker of blood glucose reflecting the previous 2 weeks. However, the effects of storage conditions and draw site on glycated albumin values are not fully understood. METHODS: Fifteen plasma samples from people with type 2 diabetes were assessed during repeated freeze-thaw rounds for 10 cycles. A further 15 samples were stored at 4°C and assessed over 3 days. Another 40 samples drawn concurrently from capillary and venous sites had their glycated albumin content compared. RESULTS: Glycated albumin concentration did not alter over 10 freeze-thaw cycles (P=.856), or after 72 hours at 4°C (P=.962). Capillary and venous samples did not differ in their percentage of glycated albumin (P=.379), although lower concentrations of albumin and glycated albumin (g/dL) were observed in the capillary sample (P<.001). CONCLUSION: Glycated albumin in plasma appears relatively stable when exposed to common laboratory conditions, reducing a potential confounder to its use as a marker of blood glucose control. The glycated albumin (%) in samples from capillary and venous sites was comparable, suggesting the potential of rapid or portable assessment devices that require a finger prick.

The sensitivity and specificity of thyroglobulin concentration using repeated measures of urinary iodine excretion.

PURPOSE: Iodine deficiency affects 30% of populations worldwide. The amount of thyroglobulin (Tg) in blood increases in iodine deficiency and also in iodine excess. Tg is considered as a sensitive index of iodine status in groups of children and adults, but its usefulness for individuals is unknown. The aim of this study was to determine the diagnostic performance of Tg as an index of iodine status in individual adults. METHODS: Adults aged 18-40 years (n = 151) provided five spot urine samples for the measurement of urinary iodine concentration expressed as µg/L (UIC), µg/g of creatinine (I:Cre), and µg/day (estimated UIE); the mean of the five samples was used as the reference standard. Participants also provided a blood sample for the determination of Tg, thyroid-stimulating hormone (TSH), and free thyroxine (FT4). RESULTS: The median of UIC, I:Cre, estimated UIE, and Tg was 72 (range 16-350) µg/L, 90 (range 33-371) µg/g, 129 (range 41-646) µg/day, and 16.4 (range 0.8-178.9) µg/L, respectively. Using Tg cut-offs of >10, >11, >13, and >15 µg/L, the sensitivity and specificity for UIC, I:Cre, and estimated UIE ranged from 52 to 79% and 20-48%, respectively, below the acceptable value of ≥80%. Furthermore, receiver-operating characteristic (ROC) curves for Tg using the three measurements of urinary iodine were situated close to the chance line and the area under the curve ranged from 0.49 to 0.52. CONCLUSIONS: The results from this cross-sectional study indicate that Tg has low sensitivity and specificity to repeated measures of urinary iodine excretion. Further studies are still needed to investigate the usefulness of Tg as a biomarker of individual iodine status.

Glycated albumin is associated with body mass index in euglycemic adults but is not predictive of postprandial blood glucose response.

BACKGROUND: The level of glycated albumin in circulation is an indicator of blood glucose control over the preceding 2 weeks. It is not known if the level of glycated albumin in circulation relates to an individual's postprandial blood glucose response. METHODS: Eighty-four euglycemic young adults (21.1 [3.9] years, BMI 23.9 [4.0] kg/m2 ) primarily of European descent underwent a fasted meal test of 50 g carbohydrate from white bread. Capillary blood was then sampled at regular intervals over 2 hours. Correlations were sought between glycated albumin, fasted and 2-hour post-load blood glucose measurements, incremental area under the blood glucose curve, glycemic range, body mass index (BMI), and C-reactive protein (CRP). RESULTS: When adjusted for age and sex, glycated albumin was inversely correlated with BMI (r=-.25, P=.027). No significant correlations existed for glycated albumin and postprandial markers of blood glucose control. BMI and CRP values correlate in this population (r=.30, P=.009). CONCLUSIONS: Glycated albumin in circulation is not related to postprandial blood glucose response in young euglycemic adults. Glycated albumin is lower in euglycemic adults with higher BMI values. Contrary to research with older adults or those with impaired glucose control, glycated albumin did not correlate to CRP.

Advice to walk after meals is more effective for lowering postprandial glycaemia in type 2 diabetes mellitus than advice that does not specify timing: a randomised crossover study.

AIMS/HYPOTHESIS: Regular physical activity is a cornerstone of diabetes management. We conducted a study to evaluate whether specifying the timing of walking in relation to meals enhances the benefits conferred by current physical activity guidelines. METHODS: A total of 41 adults with type 2 diabetes mellitus (mean ± SD age 60 ± 9.9 years; mean diabetes duration 10 years) participated in this randomised, crossover study. Randomisation was by a computer-generated protocol. For periods of 2 weeks, advice to walk 30 min each day was compared with advice to walk for 10 min after each main meal. Both sets of advice met current physical activity guidelines for people with type 2 diabetes mellitus. Physical activity was measured by accelerometry over the full intervention, and glycaemia was measured using continuous glucose monitoring in 5 min intervals over 7 days. The primary outcome of postprandial glycaemia was assessed during the 3 h after a meal by the incremental area under the blood glucose curve (iAUC). RESULTS: The iAUC was significantly lower when participants walked after meals compared with on a single daily occasion (ratio of geometric means 0.88, 95% CI 0.78, 0.99). The improvement was particularly striking after the evening meal (0.78, 95% CI 0.67, 0.91) when the most carbohydrate was consumed and sedentary behaviours were highest. One participant died during the 30 day washout period between interventions, but participation in this study was not judged to contribute to this unfortunate event. CONCLUSIONS/INTERPRETATION: The benefits relating to physical activity following meals suggest that current guidelines should be amended to specify post-meal activity, particularly when meals contain a substantial amount of carbohydrate. TRIAL REGISTRATION: ACTRN12613000832774 FUNDING: : This study was supported by grants from the University of Otago and the New Zealand Artificial Limb Service. Glycated albumin reagents were provided by Asahi Kasei.

Iodine Supplementation of Mildly Iodine-Deficient Adults Lowers Thyroglobulin: A Randomized Controlled Trial.

CONTEXT: An inverse relationship between thyroglobulin (Tg) and urinary iodine concentration (UIC) has been found in children, potentially making Tg a viable blood marker of iodine status. The application of Tg in adults is unknown. OBJECTIVE: The objective of the study was to determine the efficacy of Tg to assess iodine status in adults. DESIGN: This was a randomized, double-blind, placebo-controlled, clinical trial. SETTING: The study was conducted in Dunedin, New Zealand. PARTICIPANTS: Mildly iodine deficient adults (n = 112) aged 18­40 years participated in the study. INTERVENTION: Participants were supplemented with 150 µg of iodine as potassium iodate or placebo daily for 24 weeks. At baseline and 24 weeks, participants provided five casual urine samples for UIC determination; serum TSH and free T4 (FT4) was also measured. Tg was determined at baseline and 8, 16, and 24 weeks. MAIN OUTCOME MEASURES: A change in Tg concentration between the iodine-supplemented and placebo groups at 24 weeks. RESULTS: At baseline, the overall median UIC was 65 µg/L, confirming that participants were mildly iodine deficient (ie, median UIC between 50 and 99 µg/L). The overall median Tg was 16.6 µg/L; TSH and FT4 were within normal reference ranges. At 24 weeks, the median UIC of the placebo and supplemented groups was significantly different, 79 and 168 µg/L, respectively (P < .001). Tg in the iodine-supplemented group decreased by 12%, 20%, and 27% compared with the placebo group at 8 (P = .045), 16 (P < .001), and 24 weeks (P < .001); there were no significant changes in TSH and FT4. CONCLUSION: Improved iodine status as assessed by UIC was associated with a concomitant decrease in Tg concentration, demonstrating that Tg is a useful biomarker of iodine status in a group of adults.

The use of different reference foods in determining the glycemic index of starchy and non-starchy test foods.

BACKGROUND: Glycemic index (GI) is intended to be a property of food but some reports are suggestive that GI is influenced by participant characteristics when glucose is used as a reference. OBJECTIVE: To examine the influence of different reference foods on observed GI. DESIGN: The GIs of five varieties of rice and a sugary beverage (LoGiCane™) were tested in 31 European and 32 Chinese participants using glucose or jasmine rice as reference foods. The GIs of two ready-to-eat breakfast cereals (Kellogg's cornflakes and Sustain) were tested in 20 younger and 60 older people using glucose or Sustain as reference foods. RESULTS: The GIs of rice tended to be higher in the Chinese compared with the Europeans when glucose was used as a reference (jasmine 80 vs 68, P = 0.033; basmati 67 vs 57, P = 0.170; brown 78 vs 65, P = 0.054; Doongara 67 vs 55, P = 0.045; parboiled 72 vs 57, P = 0.011). There were no between-group differences in GI when jasmine rice was the reference. The GIs of breakfast cereals tended to be lower in younger compared with older groups (cornflakes 64 vs 81, P = 0.008; Sustain 56 vs 66, P = 0.054). There was no between-group difference in the GI of cornflakes when Sustain was the reference (cornflakes 115 vs 120, P = 0.64). There was no ethnic difference in GI when glucose was the reference for another sugary food (LoGiCane™ 60 vs 62; P = 0.69). CONCLUSIONS: A starchy reference may be more appropriate than a glucose beverage when attempting to derive universally applicable GI values of starchy foods. TRIAL REGISTRATION: The Chinese/European trial is registered with the Australian New Zealand Clinical Trials Registry as ACTRN12612000519853.

Cross-sectional dietary deficiencies among a prison population in Papua New Guinea.

BACKGROUND: To investigate the dietary adequacy of prisoners of Beon Prison, Madang, Papua New Guinea in response to a report of possible nutritional deficiency. METHODS: We undertook an observational, cross-sectional study. All 254 male inmates (May 2010) were eligible to answer a validated interview-based questionnaire; to have a comprehensive dietary assessment; and to provide blood for biochemical analysis (α-tocopherol, ß-carotene, lutein, thiamin, riboflavin, niacin, folate, homocysteine, zinc, ferritin, and vitamins A, B12 and C). Prison guards were invited to participate as a comparison group. RESULTS: 148 male prisoners (58.3%) and 13 male prison guards participated. Prison rations consisted of white rice fortified with thiamin, niacin, and iron, tinned tuna, tinned corned beef, water crackers, and black tea, with occasional intakes of fruit and vegetables. Some prisoners received supplementary food from weekend visitors. From assessment of the prisoners dietary data, median intakes of calcium (137 mg), potassium (677 mg), magnesium (182 mg), riboflavin (0.308 mg), vitamin A (54.1 µg), vitamin E (1.68 mg), vitamin C (5.7 mg) and folate (76.4 µg) were found to be below estimated average requirements (EAR). CONCLUSIONS: The prisoners diets are likely lacking in several micronutrients and recommendations for dietary change have been made to the prison authorities. Ongoing vigilance is required in prisons to ensure the basic human right of access to a nutritionally adequate diet is being observed.

Optic neuropathy among a prison population in Papua New Guinea.

PURPOSE: To estimate the prevalence of optic neuropathy (ON) among prisoners in a provincial prison in Papua New Guinea, and to explore risk factors for this condition among this population. METHODS: Cross-sectional observation study of 148 male prisoners aged ≥18 years using an interview-based questionnaire, assessment of visual and nervous system function, ocular examination, and blood analysis (α-tocopherol, ß-carotene, lutein, folate, homocysteine, holotranscobalamin II, riboflavin, selenium, thiamin, and vitamins A, B(12) and C). Likelihood of the presence of ON was based on ordered groups determined by weighted combination of optic nerve head appearance and visual dysfunction (acuity, field, color perception). Main outcome measures were prevalence and associations of ON. RESULTS: Sample prevalence of clinical ON was 10.4% (95% confidence interval [CI], 6.2-16.8). No cases were found of unexplained non-visual nervous system dysfunction, including peripheral neuropathy. Increasing age (p = 0.001), length of current (p = 0.002) and lifetime (p = 0.03) incarceration, and duration of smoking by current smokers (p = 0.001) were associated with increased ON likelihood. However, when age-controlled, the smoking duration association was not maintained (p = 0.6). Prisoners were folate deficient. Adjusting for age and duration of current incarceration, whole blood (p = 0.02) and red blood cell (p = 0.04) folate concentrations were inversely associated with ON likelihood. No association was found for any other assessed demographic, lifestyle or biochemical measure. CONCLUSIONS: A cluster of ON associated with folate deficiency has been identified. Recommendations for dietary change and micronutrient supplementation have been made.