Low dietary fiber and high protein intakes associated with newly diagnosed diabetes in a remote aboriginal community

Measurement of diet quality among First Nations peoples in Canada and associations with health: a scoping review

BACKGROUND

Given the increasing number and the diversity of dietary quality indices used for research, and the differences between settings, there is a need to identify valid indices of dietary quality in different contexts and populations and to identify their associations with health-related outcomes.

OBJECTIVES

The primary objective of this scoping review is to identify the tools used in determining dietary quality among First Nations and to describe the changes in diet. The second objective is to describe the associations identified in studies that have measured the relationship between health and dietary quality among First Nations; and the third objective is to identify factors associated with diet quality.

METHODS

PubMed, Embase, CINAHL, Global Health, and Web of Science were searched from inception to June 2021 and updated in February 2022. Articles were included if the research subjects were First Nations, or if articles reported disaggregated subset data for First Nations. Eligible studies focused on nutrition and diet and were published in English or French.

RESULTS

A total of 151 articles were included in the analysis. Studies used several indicators to measure if individuals adhered to dietary guidelines. Traditional food consumption was frequently used as an indicator of diet quality (n = 96). The consumption of store-bought foods was used as an indicator in 28 studies. Some studies used other diet quality indicators such as the Healthy Eating Index (n = 5) and ultra-processed food "NOVA" classification (n = 6). A trend for decreasing traditional food intake over time was apparent, alongside an increase in store-bought food intake. This trend was accompanied with declining health status, including the increased prevalence of overweight and obesity, diabetes, metabolic diseases, and dental caries.

CONCLUSION

This scoping review showed that diet quality among First Nations is improved when traditional foods are consumed. Reduced diet quality was associated with increased risk of noncommunicable diseases.

The V-shaped curve relationship between fasting plasma glucose and human serum albumin in a large health checkup population in China

BACKGROUND

This study aimed to investigate the relationship between fasting plasma glucose (FPG) and human serum albumin (HSA) in a large health checkup population in China.

METHODS

In this cross-sectional health checkup study, we enrolled a population of 284,635 subjects from Wuhu between 2011 and 2016. All participants completed the physical examination, blood biochemical examination, and blood routine examination.

RESULTS

The prevalence of diabetes in men and women was 6.11% and 2.98%, respectively. The average level of HSA and FPG was significantly higher in men than in women (48.44 ± 3.25 vs. 47.14 ± 3.22, P < 0.0001; 5.50 ± 1.26 vs. 5.26 ± 0.94, P < 0.0001). There were significant differences in blood biochemistry and blood routine values by gender. After adjusting for confounding factors, the results showed that FPG and HSA were a V-shaped curve, and the threshold value of HSA was 40.7 mmol/L. FPG and HSA still showed a V-shaped curve after stratification by gender and age. In the male group, FPG decreased with HSA when HSA<42.3 mmol/L, and increased when HSA ≥ 42.3 mmol/L. In the female group, FPG decreased with HSA when HSA<35.7 mmol/L, and increased when HSA ≥ 35.7 mmol/L. In the age<65 group, FPG decreased with HSA when HSA<37.5 mmol/L, and increased when HSA ≥ 37.5 mmol/L. In the age ≥ 65 group, FPG decreased with HSA when HSA<43.2 mmol/L, and increased when HSA ≥ 43.2 mmol/L.

CONCLUSIONS

A V-shape relationship exists between fasting plasma glucose and human serum albumin among the Chinese health checkup population studied.

Dietary Patterns and Type 2 Diabetes Mellitus in a First Nations Community

BACKGROUND

Type 2 diabetes mellitus is a growing concern worldwide, particularly in Indigenous communities, which have undergone a marked nutrition transition characterized by reduced intakes of traditional foods and increased intakes of market foods. Few studies have assessed the relationships between differing dietary patterns and risk for type 2 diabetes in Indigenous communities in Canada. The objective of the study was to characterize dietary patterns using factor analysis (FA) and to relate these patterns to the incidence of type 2 diabetes after 10 years of follow up in a First Nations community in Ontario, Canada.

METHODS

We conducted a prospective analysis of 492 participants in the SLHDP who did not have diabetes at baseline (1993 to 1995) and were followed for 10 years. A food-frequency questionnaire was administered, and FA was used to identify patterns of food consumption. Multivariate logistic regression analyses determined associations of food patterns with incident type 2 diabetes, adjusting for sociodemographic and lifestyle confounders.

RESULTS

At follow up, 86 participants had developed incident type 2 diabetes. FA revealed 3 prominent dietary patterns: Balanced Market Foods, Beef and Processed Foods and Traditional Foods. After adjustment for age, sex, waist circumference, interleukin-6 and adiponectin, the Beef and Processed Foods pattern was associated with increased risk for incident type 2 diabetes (OR=1.38; 95% CI 1.02, 1.86). In contrast, the Balanced Market Foods and Traditional Foods Patterns were not significantly associated with type 2 diabetes.

CONCLUSIONS

Dietary interventions should encourage reduced consumption of unhealthful market foods, in combination with improvements in local food environments so as to increase access to healthful foods and reduce food insecurity in Indigenous communities.

High protein and cholesterol intakes associated with emergence of glucose intolerance in a low-risk Canadian Inuit population

Objective

The rate of type 2 diabetes mellitus among Inuit is 12·2 % in individuals over 50 years of age, similar to the Canadian prevalence. Given marked dietary transitions in the Arctic, we evaluated the dietary and other correlates of not previously diagnosed glucose intolerance, defined as type 2 diabetes mellitus, impaired fasting glucose or impaired glucose tolerance.

Design

Cross-sectional analyses were limited to adults with a completed 2 h oral glucose tolerance test and without pre-existing diabetes. Anthropometric assessments, health and medication usage questionnaires and a 24 h dietary recall were administered.

Setting

Canadian International Polar Year Inuit Health Survey (2007–2008).

Subjects

Inuit adults (n 777).

Results

Glucose intolerance was associated with older age and adiposity. Percentage of energy from protein above the Acceptable Macronutrient Distribution Range of 35 %, compared with intake within the range, was associated with increased odds of glucose intolerance (OR=1·98; 95 % CI 1·09, 3·61) in multivariable analyses. Further, cholesterol intake in the highest three quartiles combined (median exposures of 207, 416 and 778 mg/d, respectively) compared with the lowest quartile (median intake of 81 mg/d) was associated with glucose intolerance (OR=2·15; 95 % CI 1·23, 3·78) in multivariable analyses. Past-day traditional food consumption was borderline protective of glucose intolerance (P=0·054) and high fibre intake was not significantly protective (P=0·08).

Conclusions

The results contribute to the existing literature on high protein and cholesterol intakes as they may relate to diabetes risk.

Quality of diet is associated with insulin resistance in the Cree (Eeyouch) indigenous population of northern Québec

BACKGROUND AND AIMS

Indigenous people worldwide have a greater disease burden than their non-aboriginal counterparts with health challenges that include increased obesity and higher prevalence of diabetes. We investigate the relationships of dietary patterns with nutritional biomarkers, selected environmental contaminants and measures of insulin resistance in the Cree (Eeyouch) of northern Québec Canada.

METHODS AND RESULTS

The cross-sectional 'Nituuchischaayihitaau Aschii: A Multi-Community Environment-and-Health Study in Eeyou Istchee' recruited 835 adult participants (≥18 y) from 7 communities in the James Bay region of northern Québec. The three dietary patterns identified by principal component analysis (PCA) were: inland and coastal patterns with loadings on traditional foods, and a junk food pattern with high-fat and high-sugar foods. We investigated dietary patterns scores (in quantiles) in relation with nutritional biomarkers, environmental contaminants, anthropometry, blood pressure, fasting plasma glucose and insulin, and insulin resistance. Homeostatic model assessment (HOMA-IR) was used as surrogate markers of insulin resistance. ANCOVA ascertained relationships between dietary patterns relationship and outcomes. Greater scores for the traditional patterns were associated with higher levels of n-3 fatty acids, mercury and polychlorinated biphenyls (PCBs) (P trend <0.001). Higher scores for the junk food pattern were associated with lower levels of PCBs and Vitamin D, but higher fasting plasma insulin and HOMA-IR.

CONCLUSION

Our results suggest that poor diet quality accompanied greater insulin resistance. Impacts of diet quality on insulin resistance, as a sign of metabolism perturbation, deserve more attention in this indigenous population with high rates of obesity and diabetes.

How is nutrition transition affecting dietary adequacy in Eeyouch (Cree) adults of Northern Quebec, Canada?

Rapid development, including the building of hydroelectric projects and roads in remote areas of Northern Quebec, Canada, has led to concerns about the contamination of traditional foods (TF) and a transition to a diet characterized by increased commercial food intake. A cross-sectional study of 850 Cree adults, aged ≥19 years, from 7 of the 9 Eeyouch communities was conducted during the spring and summer seasons of 2005-2008. Anthropometric measures were collected. TF and dietary intake were assessed using food-frequency questionnaires (FFQs) and 24-h recalls. Obesity was high, with 77% of the women and 64% of the men classified as obese. Past-year TF consumption was 100%, and 41% of participants reported eating TF on the 24-h recall. TF intake as reported on both the FFQs and the 24-h recalls was higher in individuals aged >50 years of age and in men, relative to younger adults and women, respectively. TF consumption increased protein, vitamin D, iron, and magnesium in all individuals, and energy, cholesterol, magnesium, sodium, and zinc in men aged 19-50 years; it decreased vitamin C in men and women aged ≥51 years. Participants reported drinking a mean daily 0.78 ± 1.34 cans of soft drinks or other high-sugar beverages per day or 5.28% ± 8.92% of total energy. It is important to identify behaviours that are contributing to obesity and its health consequences in this population and to find culturally appropriate ways to promote the consumption of TF and to reduce the consumption of energy-dense and nutrient-poor beverages and food items.

The association between serum albumin levels and metabolic syndrome in a rural population of Korea

OBJECTIVES

A positive association between serum albumin levels and metabolic syndrome has been reported in observation studies, but it has not been established in the Korean population. The purpose of this study was to evaluate the association between serum albumin levels and the presence of metabolic syndrome among a sample of apparently healthy Korean adults.

METHODS

This cross-sectional study analyzed data of 3189 community-dwelling people (1189 men and 2000 women) who were aged 40 to 87 years and were living in a rural area in Korea. Serum albumin levels were classified into quartile groups for each sex. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III guidelines with an adjusted waist circumference cut-off value (≥90 cm for men and ≥85 cm for women). An independent association between serum albumin levels and metabolic syndrome was assessed by multiple logistic regression analysis.

RESULTS

Higher serum albumin levels were associated with increased prevalence of metabolic syndrome. The odds ratio (95% confidence interval) of the prevalence of metabolic syndrome for the highest versus the lowest serum albumin quartiles was 2.81 (1.91 to 4.14) in men and 1.96 (1.52 to 2.52) in women, after adjusting for age, smoking status, alcohol consumption, and physical activity. When each metabolic abnormality was analyzed separately, higher serum albumin levels were significantly associated with hypertriglyceridemia and hyperglycemia in both sexes, and with abdominal obesity in men.

CONCLUSIONS

These results suggest that higher serum albumin levels are positively associated with an increased risk of metabolic syndrome in Korean adults.

Developmental origins of type 2 diabetes in aboriginal youth in Canada: it is more than diet and exercise

Type 2 diabetes mellitus (T2DM) is classically viewed as a disease of adults caused by poor nutrition, physical inactivity, and obesity. However, with increasing awareness of the heterogeneity of T2DM, new risk factors are being identified that add complexity. Some of these new risk factors have been identified in Canadian people with Aboriginal Oji-Cree heritage, a group that demonstrates one of the highest rates of T2DM in the world. This high prevalence may be due to the rapid change, over the past 50 years, away from their traditional way of life on the land. Another environmental change is the increased rate of pregnancies complicated by obesity, gestational diabetes, or T2DM, resulting in more children being exposed to an abnormal intrauterine environment. Furthermore, the Oji-Cree of central Canada possesses the unique HNF-1α G319S polymorphism associated with reduced insulin secretion. We propose that intrauterine exposure to maternal obesity and T2DM, associated with the HNF-1α G319S polymorphism, results in fetal programming that accelerates the progression of early-onset T2DM. This paper describes the evolution of T2DM in children with a focus on the Oji-Cree people over the past 25 years and the unique prenatal and postnatal gene-environment interaction causing early-onset T2DM.

Effects of supplemented isoenergetic diets differing in cereal fiber and protein content on insulin sensitivity in overweight humans

BACKGROUND

Despite their beneficial effects on weight loss and blood lipids, high-protein (HP) diets have been shown to increase insulin resistance and diabetes risk, whereas high-cereal-fiber (HCF) diets have shown the opposite effects on these outcomes.

OBJECTIVE

We compared the effects of isoenergetic HP and HCF diets and a diet with moderate increases in both cereal fibers and dietary protein (Mix diet) on insulin sensitivity, as measured by using euglycemic-hyperinsulinemic clamps with infusion of [6,6-(2)H(2)]glucose.

DESIGN

We randomly assigned 111 overweight adults with features of the metabolic syndrome to 1 of 4 two-phased, 18-wk isoenergetic diets by group-matching. Per 3-d food protocols, the percentages of energy derived from protein and carbohydrates and the intake of cereal fiber per day, respectively, were as follows-after 6 wk: 17%, 52%, and 14 g (control); 17%, 52%, and 43 g (HCF); 28%, 43%, and 13 g (HP); 23%, 44%, and 26 g (Mix); after 18 wk: 17%, 51%, and 15 g (control); 17%, 51%, and 41 g (HCF); 26%, 45%, and 14 g (HP); and 22%, 46%, and 26 g (Mix). Eighty-four participants completed the study successfully and were included in the final analyses. Adherence was supported by the provision of tailored dietary supplements twice daily in all groups.

RESULTS

Insulin sensitivity expressed as an M value was 25% higher after 6 wk of the HCF diet than after 6 wk of the HP diet (subgroup analysis: 4.61 ± 0.38 compared with 3.71 ± 0.36 mg · kg(-1) · min(-1), P = 0.008; treatment × time interaction: P = 0.005). Effects were attenuated after 18 wk (treatment × time interaction: P = 0.054), which was likely explained by lower adherence to the HP diet. HP intake was associated with a tendency to increased protein expression in adipose tissue of the translation initiation factor serine-kinase-6-1, which is known to mediate amino acid-induced insulin resistance. Biomarkers of protein intake indicated interference of cereal fibers with dietary protein absorption.

CONCLUSION

Greater changes in insulin sensitivity after intake of an isoenergetic HCF than after intake of an HP diet might help to explain the diverse effects of these diets on diabetes risk. This trial is registered at clinicaltrials.gov as NCT00579657.

Development and use of FFQ among adults in diverse settings across the globe

In nutritional epidemiology, development of valid dietary assessment instruments specific to populations in diverse settings is of paramount importance. Such instruments are essential when trying to characterise dietary patterns and intake, investigate diet-disease associations, inform and evaluate nutrition interventions, assess nutrient-gene interactions, conduct cross-country comparison studies and monitor nutrition transitions. The FFQ is a relatively inexpensive tool for measuring long-term dietary intake for large populations and for allowing researchers to track dietary changes over time. However, FFQ must be population specific to capture the local diet and available foods. Collecting 24-h dietary recalls and utilising community feedback to build the FFQ ensures that a culturally appropriate instrument is developed. This article presents several examples describing FFQ development and utilisation in different settings globally. In the Canadian Arctic, FFQ were developed and utilised to inform and evaluate a community-based intervention programme, characterise the diet and track dietary changes occurring among Inuit and Inuvialuit, populations experiencing rising rates of chronic disease and likely to be extremely vulnerable to the potential effects of climate change. Another example is an FFQ developed to assess sodium intake and evaluate a sodium reduction trial in a high-risk population in Barbados. An example is provided from Brazil, where an FFQ was developed to assess associations between diet, heterocyclic aromatic amines and colorectal adenoma among Japanese Brazilians and to conduct cross-country comparisons. These and other case studies highlight the diversity in dietary intake between populations and the need for FFQ to be developed to capture this diversity.

Dietary intake and development of a quantitative food-frequency questionnaire for a lifestyle intervention to reduce the risk of chronic diseases in Canadian First Nations in north-western Ontario

Objectives

To characterise the diet of First Nations in north-western Ontario, highlight foods for a lifestyle intervention and develop a quantitative food-frequency questionnaire (QFFQ).

Design

Cross-sectional survey using single 24 h dietary recalls.

Setting

Eight remote and semi-remote First Nations reserves in north-western Ontario.

Subjects

129 First Nations (Oji-Cree and Ojibway) men and women aged between 18 and 80 years.

Results

The greatest contributors to energy were breads, pasta dishes and chips (contributing over 20 % to total energy intake). ‘Added fats’ such as butter and margarine added to breads and vegetables made up the single largest source of total fat intake (8·4 %). The largest contributors to sugar were sugar itself, soda and other sweetened beverages (contributing over 45 % combined). The mean number of servings consumed of fruits, vegetables and dairy products were much lower than recommended. The mean daily meat intake was more than twice that recommended. A 119-item QFFQ was developed including seven bread items, five soups or stews, 24 meat- or fish-based dishes, eight rice or pasta dishes, nine fruits and 14 vegetables. Frequency of consumption was assessed by eight categories ranging from ‘Never or less than one time in one month’ to ‘two or more times a day’.

Conclusion

We were able to highlight foods for intervention to improve dietary intake based on the major sources of energy, fat and sugar and the low consumption of fruit and vegetable items. The QFFQ is being used to evaluate a diet and lifestyle intervention in First Nations in north-western Ontario.

Determining the relationship between dietary carbohydrate intake and insulin resistance

Insulin resistance underlies type 2 diabetes, CVD and the metabolic syndrome, driven by changes in diet, lifestyle, energy over–consumption and obesity. Nutritional recommendations for insulin resistance remain an area of controversy, particularly the quantity and types of dietary carbohydrate. The present review gives an overview of insulin resistance, its relationship to impaired insulin secretion and the metabolic syndrome, research methodologies used to measure insulin action and the epidemiological and intervention studies on the relationship between dietary carbohydrate and insulin resistance. Epidemiological studies provide little evidence to suggest that total dietary carbohydrate predicts risk of type 2 diabetes, and high–carbohydrate, high–fibre diets with low–glycaemic index (GI) may even contribute to diabetes prevention. Despite inherent limitations associated with techniques used to measure insulin resistance and dietary assessment, most intervention studies reveal an increase in glucose tolerance or insulin sensitivity with high–carbohydrate, low–fat diets in non–diabetic and diabetic individuals. When energy is restricted the source or reduced content of carbohydrate does not appear to be as important as fat for body weight. Thus, low energy intake is key to weight loss and augmentation of insulin sensitivity. Given this, widespread adoption of popular low–carbohydrate high–fat diets highlights the necessity to evaluate dietary interventions regarding safety and metabolic effects. While current evidence supports FAO/WHO recommendations to maintain a high–carbohydrate diet with low–GI foods, the relationships between carbohydrate and insulin sensitivity remains an important research area. Emerging technologies should further enhance understanding of gene–diet interactions in insulin resistance, providing useful information for future nutrition policy decisions.

Long term nutritional intake and the risk for non-alcoholic fatty liver disease (NAFLD): a population based study

BACKGROUND/AIMS

Weight loss is considered therapeutic for patients with NAFLD. However, there is no epidemiological evidence that dietary habits are associated with NAFLD. Dietary patterns associated with primary NAFLD were investigated.

METHODS

A cross-sectional study of a sub-sample (n=375) of the Israeli National Health and Nutrition Survey. Exclusion criteria were any known etiology for secondary NAFLD. Participants underwent an abdominal ultrasound, biochemical tests, dietary and anthropometric evaluations. A semi-quantitative food-frequency questionnaire was administered.

RESULTS

After exclusion, 349 volunteers (52.7% male, mean age 50.7+/-10.4, 30.9% primary NAFLD) were included. The NAFLD group consumed almost twice the amount of soft drinks (P=0.03) and 27% more meat (P<0.001). In contrast, the NAFLD group consumed somewhat less fish rich in omega-3 (P=0.056). Adjusting for age, gender, BMI and total calories, intake of soft drinks and meat was significantly associated with an increased risk for NAFLD (OR=1.45, 1.13-1.85 95% CI and OR=1.37, 1.04-1.83 95% CI, respectively).

CONCLUSIONS

NAFLD patients have a higher intake of soft drinks and meat and a tendency towards a lower intake of fish rich in omega-3. Moreover, a higher intake of soft drinks and meat is associated with an increased risk of NAFLD, independently of age, gender, BMI and total calories.

Type 2 diabetes and impaired glucose tolerance in aboriginal populations: a global perspective

OBJECTIVE

To perform a systematic review of the prevalence of type 2 diabetes and impaired glucose tolerance (IGT) in aboriginal populations worldwide.

RESEARCH DESIGN AND METHODS

A Medline search from 1966 to 2005 was conducted. Studies were selected if they utilized accepted diagnostic criteria for type 2 diabetes. Year of study, sample size, response rate, age range, and prevalence of type 2 diabetes and IGT were documented.

RESULTS

Forty-two studies were selected, comprising 59 populations. Although the majority demonstrated a several-fold elevation of type 2 diabetes prevalence as compared to non-aboriginal populations, this was not a universal finding; a small number of populations studied actually had a low prevalence of type 2 diabetes and IGT. Lower prevalences were found in rural compared with urban populations. Interestingly, we were also able to document an inverse relationship between the ratio of IGT/type 2 diabetes and type 2 diabetes prevalence. These data are consistent with the hypothesis that those populations with the very highest rates of type 2 diabetes appear to have progressed past the prediabetes stages in the natural history of this metabolic disorder.

CONCLUSIONS

Type 2 diabetes and IGT prevalence rates vary widely amongst the world's aboriginal populations. Despite very different histories and cultures, the consequences of rapid changes in nutrition and exercise appear to have very similar metabolic consequences on aboriginal populations, the magnitude of which may be determined by the strength of the genetic susceptibility.

Resistance training and dietary protein: effects on glucose tolerance and contents of skeletal muscle insulin signaling proteins in older persons

BACKGROUND

Resistance training (RT) and dietary protein independently influence indexes of whole-body glucose control, though their synergistic effects have not yet been documented.

OBJECTIVE

This study assessed the influence of dietary protein intake on RT-induced changes in systemic glucose tolerance and the contents of skeletal muscle insulin signaling proteins in healthy older persons.

DESIGN

Thirty-six older men and women (age: 61 +/- 1 y) performed RT (3 times/wk for 12 wk) and consumed either 0.9 g protein . kg(-1) . d(-1) [lower-protein (LP) group; approximately 112% of the Recommended Dietary Allowance (RDA)] or 1.2 g protein . kg(-1) . d(-1) [higher-protein (HP) group; approximately 150% of the RDA]; the HP group consumed more total, egg, and dairy proteins.

RESULTS

After RT, body weight was unchanged; whole-body protein and water masses increased, and fat mass decreased with no significantly different responses observed between the LP and HP groups. The RT-induced improvement in oral glucose tolerance (decreased area under the curve, AUC) was not significantly different between the groups (LP: -28%; HP: -25%). The insulin (-21%) and C-peptide (-14%) AUCs decreased in the LP group but did not change significantly in the HP group. Skeletal muscle insulin receptor, insulin receptor substrate-1, and Akt contents were unchanged, and the amount of atypical protein kinase C zeta/lambda (aPKC zeta/lambda), a protein involved with insulin signaling, increased 56% with RT, independent of protein intake.

CONCLUSION

These results support the hypothesis that older persons who consume adequate or moderately high amounts of dietary protein can use RT to improve body composition, oral glucose tolerance, and skeletal muscle aPKC zeta/lambda content without a change in body weight.

Integrating conventional science and aboriginal perspectives on diabetes using fuzzy cognitive maps

There is concern among Aboriginal communities in Canada that conventional approaches to the treatment of diabetes are ineffective in part because they fail to recognize the local Aboriginal perspective on the causal determinants of diabetes. While this shortcoming has been recognized, there have been no explicit attempts to practically define these perspectives and prescribe how conventional health management might be altered to incorporate them. In part, this may be due to difficulties in communicating Aboriginal perspectives in a manner which permits incorporation into conventional science-based frameworks. Here we use fuzzy cognitive mapping (FCM) as a technique to represent and compare Canadian Aboriginal and conventional science perspectives on the determinants of diabetes as contained in published articles drawn from a search of Medline and PubMed (1966-2005). The FCM allows for a detailed description of the complex system of culture, spirituality and balance at the root of the Aboriginal view. It also highlights how, for these less tangible factors, it is possible to identify more concrete stressors and outcomes which are amenable to management and monitoring. This preliminary comparison of conventional and Aboriginal views also demonstrates the potential for FCM as a technique to extract, compare and integrate perspectives of different knowledge systems into health management and policy development.

Short-term effects of severe dietary carbohydrate-restriction advice in Type 2 diabetes--a randomized controlled trial

OBJECTIVE

This study sought to examine the effects of a 3-month programme of dietary advice to restrict carbohydrate intake compared with reduced-portion, low-fat advice in obese subjects with poorly controlled Type 2 diabetes.

RESEARCH DESIGN AND METHODS

One hundred and two patients with Type 2 diabetes were recruited across three centres and randomly allocated to receive group education and individual dietary advice. Weight, glycaemic control, lipids and blood pressure were assessed at baseline and 3 months. Dietary quality was assessed at the end of study.

RESULTS

Weight loss was greater in the low-carbohydrate (LC) group (-3.55 +/- 0.63, mean +/- sem) vs. -0.92 +/- 0.40 kg, P = 0.001) and cholesterol : high-density lipoprotein (HDL) ratio improved (-0.48 +/- 0.11 vs. -0.10 +/- 0.10, P = 0.01). However, relative saturated fat intake was greater (13.9 +/- 0.71 vs. 11.0 +/- 0.47% of dietary intake, P < 0.001), although absolute intakes were moderate.

CONCLUSIONS

Carbohydrate restriction was an effective method of achieving short-term weight loss compared with standard advice, but this was at the expense of an increase in relative saturated fat intake.

Anthropometric characteristics, dietary patterns and risk of type 2 diabetes mellitus in Vietnam

OBJECTIVE

To determine the impact of anthropometric characteristics and dietary patterns on Type 2 diabetes mellitus in Vietnam.

METHODS

Data from 144 subjects (9m/39f newly diagnosed diabetics; 18m/78f control subjects) were analyzed in this case-control study. Height, weight, waist and hip circumferences and percent body fat were measured. Dietary intakes were assessed by 24-hour recall on three non-consecutive weekdays. Fasting blood samples were collected for the analysis of plasma glucose, fructosamine, protein and lipid concentrations.

RESULTS

Although the body mass index (BMI, kg/m(2)) was similar between diabetic and control subjects, diabetic subjects had significantly greater percent body fat (31.1 +/- 5.8% vs. 27.7 +/- 6.2%) and waist-hip ratios (WHR, 0.91 +/- 0.07 vs. 0.86 +/- 0.08). Diabetic subjects had higher intakes of protein (p < 0.01), especially animal protein (p < 0.001), and consumed more meat (p < 0.01) than control subjects. Percent body fat and WHR were positively associated with diabetes (odds ratios [OR] 1.53 [95%CI 1.29-1.79] and 1.09 [95% CI 0.89-1.58], respectively) as were protein intake (OR 1.21 [95% CI 1.12-1.31]) and animal protein intake (OR 1.18 [95% CI 1.10-1.26]).

CONCLUSIONS

This study indicates that percent body fat and WHR are risk factors associated with diabetes even when the BMI is normal. Evolving dietary patterns with increasingly more protein and meat consumption may also contribute to the deterioration of glucose metabolism among Vietnamese people.

Synergism between mutant HNF1A and the metabolic syndrome in Oji-Cree Type 2 diabetes

AIMS

To determine the prevalence of the metabolic syndrome in the Sandy Lake Oji-Cree and to examine its interaction with HNF1A in association with impaired glucose tolerance and Type 2 diabetes.

METHODS

Using data collected from the Sandy Lake Health and Diabetes Project (1993-1995), the presence or absence of the metabolic syndrome was determined in 515 Oji-Cree subjects, > or = 18 years of age. In the original study, fasting plasma analytes were measured, a 75-g oral glucose tolerance test was administered, and subjects were genotyped for HNF1A G319S.

RESULTS

The unadjusted prevalence of the metabolic syndrome in the Oji-Cree adults was 29.9%. The adjusted odds ratio (OR) and 95% confidence interval for Type 2 diabetes among subjects who carried the HNF1A G319S mutation and had the modified metabolic syndrome (excluding hyperglycaemia) was 20.3 (6.94, 59.6). Adjusted ORs for Type 2 diabetes for subjects with either the HNF1A G319S mutation alone or the modified metabolic syndrome alone were 5.56 (2.85, 10.9) and 4.84 (2.53, 9.27), respectively. The risk of having impaired glucose tolerance was not influenced by the presence of either factor.

CONCLUSIONS

The risk of Type 2 diabetes was similar (approximately five-fold increased) for subjects with either the presence of the modified metabolic syndrome or the private HNF1A G319S mutation. Interestingly, when present in combination, the two independent risk factors appeared to act synergistically to confer an even greater increased risk of Type 2 diabetes.

A pilot school-based healthy eating and physical activity intervention improves diet, food knowledge, and self-efficacy for native Canadian children

The Sandy Lake school-based diabetes prevention program is a culturally appropriate intervention for Ojibway-Cree students in the 3rd, 4th, and 5th grades. This paper reports the results of the program in changing dietary intake behaviors and related psychosocial factors. Physical activity results are not included. The study was a pretest/post-test, single-sample design conducted during the 1998-1999 school year. A total of 122 students completed all 4 measurements (anthropometry, 24-h dietary recall, and 2 questionnaires), at baseline and follow-up. There were significant increases (P < 0.0001) in dietary intention, dietary preference, knowledge, and dietary self-efficacy, and in the curriculum knowledge scale between baseline and follow-up. Intervention exposure was significantly associated with being in the highest category for knowledge about foods that were low in dietary fat [Medium Exposure odds ratio (OR): 3.4; P < 0.05; High Exposure OR: 6.4; P < 0.05], being in the highest category for dietary self-efficacy (Medium Exposure OR: 3.7; P < 0.05; High Exposure OR: 3.9; P < 0.1), being in the highest category for knowledge about curriculum concepts (Medium Exposure OR: 3.4; P < 0.05; High Exposure OR: 9.4: P < 0.01), and for having met the age + 5 g dietary fiber intake/d (Medium Exposure OR: 2.9; P < 0.1; High Exposure OR: 11.0; P < 0.01). Exposure to the intervention was not associated with dietary intent or the percentage of energy from dietary fat. This program was associated with improved knowledge and the psychosocial factors related to healthy eating and dietary fiber intake of students in a remote First Nations community.

Genetic and physiological insights into the metabolic syndrome

The metabolic syndrome (MetS) is a common phenotype that is clinically defined by threshold values applied to measures of central obesity, dysglycemia, dyslipidemia, and/or elevated blood pressure, which must be present concurrently in any one of a variety of combinations. Insulin resistance, although not a defining component of the MetS, is nonetheless considered to be a core feature. MetS is important because it is rapidly growing in prevalence and is strongly related to the development of cardiovascular disease. To define etiology, pathogenesis and expression of MetS, we have studied patients, specifically Canadian families and communities. One example is familial partial lipodystrophy (FPLD), a rare monogenic form of insulin resistance caused by mutations in either LMNA, encoding nuclear lamin A/C (subtype FPLD2), or in PPARG, encoding peroxisomal proliferator-activated receptor-gamma (subtype FPLD3). Because it evolves slowly and recapitulates key clinical and biochemical attributes, FPLD seems to be a useful monogenic model of MetS. A second example is the disparate MetS prevalence between two Canadian aboriginal groups that is mirrored by disparate prevalence of diabetes and cardiovascular disease. Careful phenotypic evaluation of such special cases of human MetS by using a wide range of diagnostic methods, an approach called "phenomics," may help uncover early presymptomatic disease biomarkers, which in turn might reveal new pathways and targets for interventions for MetS, diabetes, and atherosclerosis.

Effects of a low-fat vegan diet and a Step II diet on macro- and micronutrient intakes in overweight postmenopausal women

OBJECTIVE

This study investigated the nutrient intake of overweight postmenopausal women assigned to a low-fat vegan diet or a Step II diet.

METHODS

Fifty-nine overweight (body mass index, 26 to 44 kg/m2) postmenopausal women were randomly assigned to a self-selected low-fat vegan or a National Cholesterol Education Program Step II diet in a 14-wk controlled trial on weight loss and metabolism. Nutrient intake, which was measured per 1000 kcal, was the main outcome measure. Statistical analyses included within-group and between-group t tests examining changes associated with each diet.

RESULTS

Consumption of a low-fat vegan diet was associated with greater decreases in fat, saturated fat, protein, and cholesterol intakes and greater increases in carbohydrate, fiber, beta-carotene, and total vitamin A intakes than was a Step II diet. The low-fat vegan group also increased thiamin, vitamin B6, and magnesium intakes more than the Step II group, and both groups increased folic acid, vitamin C, and potassium intakes. If considering only food sources of micronutrients, the low-fat vegan group decreased vitamin D, vitamin B12, calcium, selenium, phosphorous, and zinc intakes compared with baseline. However, with incidental supplements included, decreases were evident only in phosphorous and selenium intakes. No micronutrient decreases were found in the Step II group.

CONCLUSIONS

Individuals on a low-fat vegan or Step II diet should take steps to meet the recommended intakes of vitamin D, vitamin K, folic acid, calcium, magnesium, and zinc. Individuals on a low-fat vegan diet should also ensure adequate intakes of vitamin B12, phosphorous, and selenium.

Nutrition and prevention of type 2 diabetes

In recent years, the prevalence of type 2 diabetes has increased alarmingly worldwide, giving diabetes the dimension of an epidemic. Striking parallel increases in the prevalence of obesity reflect the importance of body fatness as a contributing factor to diabetes incidence. Moreover, it has been estimated that up to 75% of the risk of type 2 diabetes is attributable to obesity. Recent clinical trials and observational epidemiologic studies demonstrate the efficacy of lifestyle changes, including decreased energy intake, decreased fat intake, and weight loss, as well as regular participation in physical activity, in improving insulin sensitivity (SI) and reducing the risk of diabetes. This review evaluates evidence of the effect of diet on insulin resistance, insulin secretion, and glucose tolerance, and reflects on directions for future work toward primary prevention of type 2 diabetes.

Associations of dietary fiber with glucose metabolism in nondiabetic relatives of subjects with type 2 diabetes: the Botnia Dietary Study

OBJECTIVE

To study cross-sectional associations of dietary fiber intake with insulin resistance, insulin secretion, and glucose tolerance in a population at high risk for type 2 diabetes.

RESEARCH DESIGN AND METHODS

The subjects consisted of 248 male and 304 female adult nondiabetic relatives of patients with type 2 diabetes. Dietary intake was measured by means of two 3-day food records. Associations of total, water-insoluble, and water-soluble fiber with measures of glucose metabolism based on an oral glucose tolerance test, were analyzed by multiple linear regression analysis adjusting for sex, age, length of education, physical activity, BMI, waist-to-hip ratio, systolic blood pressure, and serum triglyceride and HDL cholesterol concentrations. The homeostasis model assessment insulin resistance index, the incremental 30-min serum insulin concentration divided by the incremental 30-min glucose concentration, and fasting and 2-h glucose concentrations were the outcome variables.

RESULTS

The dietary intake of total as well as water-insoluble and water-soluble fiber was inversely associated with insulin resistance: -0.17 (0.07), P = 0.012; -0.15 (0.07), P = 0.024; and -0.14 (0.07), P = 0.049 [regression coefficients (SE)]. Fiber variables were unrelated to insulin secretion and plasma glucose concentrations.

CONCLUSIONS

The results support evidence that a high intake of dietary fiber is associated with enhanced insulin sensitivity and therefore may have a role in the prevention of type 2 diabetes.

Genes, environment and Oji-Cree type 2 diabetes

The prevalence of type 2 diabetes in Canadian Oji-Cree is among the highest in the world. Our research has uncovered genetic determinants of Oji-Cree type 2 diabetes and related metabolic traits. The most important genetic discovery by far was the private G319S mutation in transcription factor HNF-1alpha, encoded by the HNF1A gene. HNF1A G319S was discovered by candidate gene sequencing and would have been missed using the currently favored strategy of genome-wide scanning. G319S was associated with increased odds of having type 2 diabetes across the whole study sample and in all subgroups, including adolescent Oji-Cree. Furthermore, G319S had specificity and positive predictive value of 97% and 95%, respectively, for developing type 2 diabetes by age 50. The protein bearing the G319S mutation had impaired function in vitro. Sigmoidal modeling showed that each dose of the G319S allele accelerated the median age of diabetes onset by about 7 yr. This approach also showed that environment more strongly accelerated the median age-of-onset of Oji-Cree diabetes onset than did G319S, which could have implications for intervention strategies to reduce the burden of this epidemic. There is also evidence for genetic determination of related metabolic traits in the Oji-Cree.

High-complex carbohydrate or lente carbohydrate foods?

Current dietary guidelines of the American Diabetes Association emphasize the importance of minimizing risk factors for cardiovascular disease while maximizing diabetes control. Potential advantages are seen for increased monounsaturated fat intake, but only the quantity rather than the quality of the carbohydrate is considered important. However, review of the carbohydrate issue suggests that many cultures now at high risk of diabetes originally consumed starchy staples higher in fiber and with a lower glycemic index than eaten currently. Furthermore, diets high in cereal fiber have been associated with improved glycemic control, and low glycemic index diets resulted in reduction in glycosylated proteins in type 1 and 2 diabetes. Finally, large cohort studies have demonstrated beneficial effects of cereal fiber and low glycemic index carbohydrate foods in reducing the risk both for diabetes and cardiovascular disease. The effect of insoluble cereal fiber is not readily explained, but a low glycemic index may result from a slower rate of carbohydrate absorption. Increased meal frequency as a model for reducing the rate of carbohydrate absorption has been shown to reduce day-long glucose and insulin levels in type 2 diabetes and reduce serum lipids in nondiabetic subjects. Therefore, there appears to be a potential role for low glycemic index, high-cereal fiber foods for prevention and treatment of diabetes. Both the nature of the dietary fat and the carbohydrate should be considered as potentially modifiable factors that together with weight control and exercise may play a role in diabetes and cardiovascular disease prevention and treatment.

Racial disparities in access to simultaneous pancreas-kidney transplantation in the United States

The purpose of our study is to assess the extent of racial differences in the access to simultaneous pancreas-kidney (SPK) transplantation and evaluate the potential influence of socioeconomic factors on access to transplantation. We performed a retrospective analysis of the US Renal Data System and United Network for Organ Sharing data on all patients with end-stage renal disease (ESRD) due to diabetes mellitus from 1988 to 1996 (n = 562, 814), including all dialysis, wait list, and transplant patients. Racial differences in incidence, prevalence, insurance coverage, employment status, and transplantation rates were calculated. Caucasians had the highest prevalence of ESRD caused by type 1 diabetes (73%), followed by blacks (22%), Hispanics (3%), Native Americans (2%), and others (<1%). Both blacks and Native Americans increased their annual incidence of ESRD caused by insulin-dependent diabetes mellitus by 10% compared with only a 3.5% increase in Caucasians, whereas incidence rates increased annually by almost 8% for both blacks and Native Americans compared with a 3% increase for Caucasians. However, Caucasians received 92% of all SPK transplants, whereas all other racial groups combined received a disproportionate minority of the remaining transplants. Lack of private insurance and unemployment status were associated with annual changes in both incidence of ESRD caused by type 1 diabetes and SPK transplant rates. In conclusion, we observed striking racial disparities for access to SPK transplantation in the United States today, which may be related to employment status, access to private insurance, and subsequent health care. Our preliminary data support current efforts to encourage Medicare and Medicaid coverage for all patients requiring SPK transplantation regardless of racial or financial status.

Overweight among children and adolescents in a Native Canadian community: prevalence and associated factors

BACKGROUND

The prevalence of pediatric obesity in North America is increasing. Native American children are at especially high risk.

OBJECTIVES

The objective was to evaluate the prevalence of pediatric overweight and associated behavioral factors in a Native Canadian community with high rates of adult obesity and type 2 diabetes mellitus.

DESIGN

Height and weight were measured in 445 children and adolescents aged 2-19 y. Fitness level, television viewing, body image concepts, and dietary intake were assessed in 242 subjects aged 10-19 y. Overweight was defined as a body mass index > or =85th percentile value for age- and sex-specific reference data from the third National Health and Nutrition Examination Survey (NHANES III). Multiple logistic regression was used to examine factors associated with overweight, with adjustment for age and sex.

RESULTS

The overall prevalence of overweight in subjects aged 2-19 y was significantly higher than NHANES III reference data [boys: 27. 7% (95% CI: 21.8, 34.5); girls: 33.7% (95% CI: 27.9, 40.1)]. In the subset aged 10-19 y, > or =5 h television viewing/d was associated with a significantly higher risk of overweight than was < or =2 h/d [odds ratio (OR) = 2.52; 95% CI: 1.06, 5.98]. Subjects in the third and fourth quartiles of fitness had a substantially lower risk of overweight than did those in the first quartile [third quartile compared with first quartile: OR = 0.24 (95% CI: 0.09, 0.66); fourth quartile compared with first quartile: OR = 0.13 (95% CI: 0.03, 0. 48)]. Fiber consumption on the previous day was associated with a decreased risk of overweight (OR = 0.69; 95% CI: 0.47, 0.99 for each 0.77 g/MJ increase in fiber intake).

CONCLUSIONS

Pediatric overweight is a harbinger of future diabetes risk and indicates a need for programs targeting primary prevention of obesity in children and adolescents.

Genetic prediction of atherosclerosis: lessons from studies in native Canadian populations

The Oji-Cree from Northern Ontario have a very high prevalence of cardiovascular disease and diabetes mellitus, whereas the Inuit from Nunavut have a very low prevalence of these diseases. There are significant differences between Oji-Cree, Inuit and white subjects with respect to the frequencies of putative 'deleterious alleles' of several candidate genes in diabetes and atherosclerosis. Specifically, compared to whites, both Oji-Cree and Inuit have an excess of 'deleterious alleles' from 12 candidate genes in atherosclerosis and/or diabetes. However, it would appear that these differences in genetic architecture are not sufficient to account for the wide disparity in disease prevalence between the two aboriginal groups. It is very likely that environmental lifestyle factors, such as maintenance of a traditional diet and an increased level of activity, can override an apparent background of genetic susceptibility to these diseases in native people. Full understanding of the genetic component will require more effort because of confounding factors such as small genetic effects, non-mendelian inheritance, gene-gene interactions and gene-environment interactions. However, even before there is a full understanding of the identity of the all the genes involved, and of how their products might contribute to disease susceptibility in an individual or a community, there would be some justification to recommend an intervention strategy at this point in time. Such an intervention strategy would stress a return to a more traditional diet and lifestyle in order to avert and reverse these disease phenotypes in Canadian aboriginal communities.

Variation by body mass index and age in waist-to-hip ratio associations with glycemic status in an aboriginal population at risk for type 2 diabetes in British Columbia, Canada

BACKGROUND

It is unclear whether obesity and age modify or confound relations between abdominal adiposity and metabolic risk factors for type 2 diabetes.

OBJECTIVE

Our objective was assess the consistency of relations between abdominal adiposity and glycemic variables across discrete categories of obesity and age.

DESIGN

We performed a stratified analysis of prevalence data from a rural screening initiative in British Columbia, Canada. Subjects were Salishan Indians, all healthy relatives of individuals with type 2 diabetes [n = 151; age: 18-80 y; body mass index (BMI, in kg/m2): 17.0-48.2]. We measured waist-to-hip ratio (WHR) (2 categories); insulin, glycated hemoglobin (Hb A1c), and 2-h glucose concentrations (2 categories); and BMI (4 categories). BMI and age-specific odds ratios (ORs) and 95% CIs were calculated.

RESULTS

WHR-glycemic variable relations were not consistent across BMI and age strata. Risks associated with high WHR were: for persons with BMIs from 25 to 29, elevated insulin (OR: 6.71; 95% CI: 1.41, 34.11) and Hb A1c (OR: 16.23; 95% CI: 2.04, 101.73) concentrations; for persons aged 18-34 y, elevated insulin concentrations [OR: indeterminate (+infinity); 95% CI: 1.89, +infinity]; and, for persons aged 35-49 y, elevated Hb A1c (OR: +infinity; 95% CI: 3.17, +infinity) and 2-h glucose (OR: 9.15; 95% CI: 1.74, 59.91) concentrations.

CONCLUSIONS

WHR discriminates risk of type 2 diabetes in overweight but not obese individuals. Abdominal adiposity is associated with elevated insulin concentrations in younger age groups and with impaired glucose control in middle-aged groups, suggesting metabolic staging by age on a continuum from insulin resistance to impaired glucose tolerance.

Specific patterns of food consumption and preparation are associated with diabetes and obesity in a Native Canadian community

We examined the relationship between usual patterns of food intake, fattiness of food preparation and consumption, and diabetes and obesity status in a Native Canadian reserve in northwestern Ontario. Patterns of intake were estimated using a 34-item food frequency instrument. Scales and scores were developed using factor analysis procedures and were tested for reliability using coefficient alpha. Impaired glucose tolerance (IGT) and diabetes status was determined by administering a 75-g glucose tolerance test. A number of the food groups appear to have a protective effect in regard to IGT and diabetes, including vegetables [odds ratio (OR) = 0.41, confidence interval (CI) = 0.18-0.91], breakfast foods (OR = 0.41, CI = 0.18-0. 93) and hot meal foods (OR = 0.29, CI = 0.11-0.78). Most of these foods are relatively high in fiber and low in fat. High consumption of junk foods and the bread and butter group was associated with substantial increases in risk for diabetes (OR = 2.40, CI = 1.13-5. 10; OR = 2.22, CI = 1.22-4.41, respectively). These foods tend to be high in simple sugars, low in fiber and high in fat. More fatty methods of food preparation are also associated with increased risk for diabetes in this population (OR = 2.58, CI = 1.11-6.02). This information has been incorporated into an ongoing community-based diabetes prevention program in the community.