Low-carbohydrate and high-fat intake among adult patients with poorly controlled type 2 diabetes mellitus

Association of dietary intake with body mass index and glycemic profile among newly diagnosed patients with type 2 diabetes mellitus

INTRODUCTION

Dietary intake plays an important role in determining body mass index (BMI) and glycemic profile in patients with type 2 diabetes mellitus (T2DM). Our aim was to describe habitual dietary intake and its associations with BMI and glycemic profile in a cohort of patients with newly diagnosed T2DM in Sri Lanka.

METHODS

A cross-sectional study was carried out among 158 patients with newly diagnosed T2DM in Galle, Sri Lanka. Data on demographic, lifestyle, and family history of diabetes mellitus, and clinical measures were collected. The dietary information was collected using a 24-h dietary recall.

RESULTS

Among the total number of study subjects, only 12.0%, 5.7% and 1.3% met the recommended daily consumption value of protein, fat, and fiber, respectively, whereas 99.4% of subjects had taken carbohydrates that exceeded the recommended consumption. There was a positive association between carbohydrate intake and BMI (0.004, [0.002], p = .048) and carbohydrate intake and glycated hemoglobin (HbA1C ) (0.001, [0.000], p = .049). Fat intake showed positive associations with BMI (0.029, [0.011], p = .006) and HbA1C (0.005, [0.002], p = .050). Protein intake showed a positive association with HbA1C (0.006, [0.003], p = .023). The aforementioned associations were observed after adjusting for demographic, lifestyle, and history of diabetes among the first-degree family members. The carbohydrate intake was positively associated with BMI (0.010, [0.003], p = .003) and HbA1C (0.001, [0.000], p = .050) with further adjustment in nutrient intake (except when used as an independent variable). Furthermore, the fat intake was associated with BMI (0.031, [0.011], p = .004) and HbA1C (0.005 [0.002], p = .050) with additional adjustments.

CONCLUSIONS

The diet of the majority of newly diagnosed T2DM patients in this cohort consisted of a higher carbohydrate intake than the recommended level. However, they did not meet the recommended daily intake of protein, fat, and fiber. Both carbohydrate and fat intake were significantly and positively associated with BMI and HbA1C in patients with newly diagnosed T2DM.

Dietary intake and physical activity in Japanese patients with type 2 diabetes: the Japan Diabetes Complication and its Prevention prospective study (JDCP study 8)

Medical nutrition therapy and exercise therapy are the cornerstones of treatment for patients with type 2 diabetes; however, there has not been a nationwide study on the actual dietary intake and physical activity status of patients since the 2000s. We aimed to clarify this in Japanese patients with type 2 diabetes using data from the Japan Diabetes Complication and its Prevention prospective (JDCP), a nationwide study launched in 2007. A total of 1992 patients with type 2 diabetes, aged 40-75 years, completed either the Brief-type, self-administered Diet History Questionnaire (1643 patients) or International Physical Activity Questionnaire (1834 patients), and their data were analyzed in this study. Mean daily energy intake for all participants was 1686.8 kcal/day, and the mean proportions of carbohydrate, protein, and fat comprising total energy intake were 60.2, 16.2, and 23.6%, respectively. The patients in this study had similar energy and nutrient intake status to patients in the 1996 Japan Diabetes Complications Study; however, Japanese patients still had higher carbohydrate and lower fat consumption than patients with diabetes in Western countries. The physical activity questionnaire reported that 31.0% of patients did not have exercise habits; this was particularly noticeable in female patients and patients under the age of 65. BMI increased from 22.7 to 24.1 kg/m² in men and 23.2 to 24.8 kg/m² in women from 1996 to 2007, respectively. Further research is required to investigate how dietary intake and physical activity associates with the risk of developing complications in type 2 diabetes patients.

A single exposure to eucalyptus smoke sensitizes rats to the postprandial cardiovascular effects of a high carbohydrate oral load

OBJECTIVE

Previous studies have shown that air pollution exposure primes the body to heightened responses to everyday stressors of the cardiovascular system. The purpose of this study was to examine the utility of postprandial responses to a high carbohydrate oral load, a cardiometabolic stressor long used to predict cardiovascular risk, in assessing the impacts of exposure to eucalyptus smoke (ES), a contributor to wildland fire air pollution in the Western coast of the United States.

MATERIALS AND METHODS

Three-month-old male Sprague Dawley rats were exposed once (1 h) to filtered air (FA) or ES (700 µg/m³ fine particulate matter), generated by burning eucalyptus in a tube furnace. Rats were then fasted for six hours the following morning, and subsequently administered an oral gavage of either water or a HC suspension (70 kcal% from carbohydrate), mimicking a HC meal. Two hours post gavage, cardiovascular ultrasound, cardiac pressure-volume (PV), and baroreceptor sensitivity assessments were made, and pulmonary and systemic markers assessed.

RESULTS

ES inhalation alone increased serum interleukin (IL)-4 and nasal airway levels of gamma glutamyl transferase. HC gavage alone increased blood glucose, blood pressure, and serum IL-6 and IL-13 compared to water vehicle. By contrast, only ES-exposed and HC-challenged animals had increased PV loop measures of cardiac output, ejection fraction %, dP/dt _max, dP/dt _min, and stroke work compared to ES exposure alone and/or HC challenge alone.

DISCUSSION AND CONCLUSIONS

Exposure to a model wildfire air pollution source modifies cardiovascular responses to HC challenge, suggesting air pollution sensitizes the body to systemic triggers.

Dietary Protein and Fat Intake Affects Diabetes Risk with CDKAL1 Genetic Variants in Korean Adults

Cyclin-dependent kinase 5 regulatory subunit-associated protein 1-like 1 (CDKAL1) is one of the strongest diabetes loci identified to date; evidence suggests that it plays an important role in insulin secretion. Dietary factors that affect insulin demand might enhance the risk of diabetes associated with CDKAL1 variants. Our aim was to examine the interactions between dietary protein and fat intake and CDKAL1 genetic variants in relation to the risk of diabetes in Korean adults. Single nucleotide polymorphisms (SNPs) were selected with a genome-wide association study (GWAS) for diabetes after adjustment for age, gender, and examination site. Using data from the Health Examinees (HEXA) Study of the Korean Genome and Epidemiology Study (KoGES), 3988 middle-aged Korean adults between 40–76 years of age (2034 men and 1954 women) were included in the study. Finally, rs7756992 located within the CDKAL1 gene region was selected from GWAS (p-value < 5 × 10⁻⁸). Multivariable logistic regression models were used to evaluate the interactions between genotypes and dietary protein and fat intake in relation to diabetes risk after adjustment for age, gender, BMI, waist circumference, physical activity, smoking status, drinking habits, and examination site. Significant interactions between CDKAL1 rs7756992 and dietary protein and fat intake for the risk of diabetes were observed in men (p-value < 0.05). In women, significant interactions between dietary protein and fat intake and CDKAL1 variants (rs7756992) were associated with increased risk of diabetes (p-value < 0.05). Dietary protein and fat intake interacted differently with CDKAL1 variants in relation to the risk of diabetes in Korean adults of both genders. These findings indicate that CDKAL1 variants play a significant role in diabetes and that dietary protein and fat intake could affect these associations.

Dietary survey in Japanese patients with type 2 diabetes and the influence of dietary carbohydrate on glycated hemoglobin: The Sleep and Food Registry in Kanagawa study

AIMS/INTRODUCTION

The present study investigated the relationship between the macronutrient energy ratio, dietary carbohydrate and glycated hemoglobin levels in Japanese patients with type 2 diabetes, to generate a potential optimal dietary intake of macronutrients for such patients.

MATERIALS AND METHODS

In total, 3,032 patients participating in the Sleep and Food Registry in Kanagawa study were evaluated. Their diets were assessed for macronutrient content through a brief self-administered dietary history questionnaire. Relevant biochemical assays were carried out.

RESULTS

The mean energy intake (±standard deviation) was 1,711 ± 645 kcal/day. The proportion of energy supplied by protein, fat and carbohydrate were 16.3, 26.8 and 52.3%, respectively. Total fiber intake was 12.6 ± 5.7 g/day. The high glycated hemoglobin (HbA1c) group (HbA1c >8%) had significantly lower protein and higher carbohydrate intake than the low HbA1c group (HbA1c <6.5%). Higher HbA1c levels were positively correlated with unfavorable metabolic factors, including elevated body mass index and excess carbohydrate intake, and negatively correlated with age, protein intake and fiber intake. Multiple regression analysis showed a significant association between HbA1c and carbohydrate intake after adjusting for sex, age and body mass index (0.104, P < 0.0001). Additionally, patients within the uppermost tertile for the percentage of total energy intake from carbohydrate (>60%) were most likely to have high HbA1c levels. HbA1c was significantly correlated with carbohydrate (%E) in all age groups and in patients taking one or two antidiabetic drugs.

CONCLUSIONS

The dietary carbohydrate:energy ratio has a positive correlation with HbA1c, suggesting that avoiding excessive carbohydrate intake (>60%) might help foster glycemic control.

Diets along with interval training regimes improves inflammatory & anti-inflammatory condition in obesity with type 2 diabetes subjects

Background

Different physical activities and diets change the regulation of inflammations in both type 2 diabetes (T2D) patients and obese individuals, but the effect of both (Physical activity and diet) on pro/anti-inflammations has remained unknown. We investigated pro/anti-inflammations control, cardiovascular function, and total physiological parameters before and after 24 weeks of low volume high intensity interval training (HIIT) on a cycle ergometer along with four dietary regimes in obesity with T2D patients.

Methods

33 non-active obesity T2D patients (BMI ≥ 30) midges (47 yrs. ± 5) were volunteered to participate and randomly divided into three experimental(n = 11) [(1) LCD = low Carbohydrate Diet, (2) LFD = Low Fat Diet and (3) HFD = High Fat Diet)] and one control (n = 9) [ND = normal diet] groups. The whole groups performed underwent 8-week dietary regimes and then performed 3 days/weeks (3 set 10 × 60 s) HIIT on a cycle ergometer for 12 weeks, which followed by a 4-week diet period again. Also, prior to and after 8 weeks diet-12 weeks High Intensity Interval Training (HIIT) and 4 weeks diet 2-h oral glucose tolerance test (OGTT), resting blood pressure, incremental maximal oxygen uptake (VO2peak) cycle ergometer test and blood sample was collected from the subjects in order to measure pro/anti-inflammatory cytokines (IL-6, TNF-α, leptin, resistin, adiponectin, and FGF21).

Results

After 24 weeks of intervention, the results indicated that the highest improvement in the percentage of changes in glucose happened in LCD (-34.76), insulin in ND (+16.43), cholesterol in LCD (-33.35), LDL in LFD (-9.14), HDL in LCD (+41.81), TG in LCD (-40.71), weight in LCD (-12.49) and HOMA-IR in HFD (-6.82). The results also indicated that after 24 weeks of HIIT and diet interventions, highest benefit percentage change IL-6, resistin and leptin occurred in LCD (-32.10, -28.29 and - 53.92, respectively), TNF-α, FGF21 and adiponectin in LFD (-48.06, +55.30 and + 42.32, respectively). However, these changes were observed in other groups.

Conclusions

These results demonstrated that HIIT along with low carbohydrate regimes improves overall cardiovascular parameters and reduce pro-inflammatory markers and increase anti-inflammatory markers in type 2 diabetic patients. Additionally, as with HIIT along with low carbohydrate, HIIT coupled with low fat would improve inflammation markers, though these effects were less significant. These findings suggest that HIIT along with low carbohydrate is a beneficial exercise and dietary strategy in T2D patients.

Is the Proportion of Carbohydrate Intake Associated with the Incidence of Diabetes Complications?-An Analysis of the Japan Diabetes Complications Study

The appropriate proportions of macronutritional intake have been controversial in medical nutritional therapy for diabetes, and evidence of the effects of carbohydrate consumption on diabetes complications in prospective settings is sparse. We investigated the relationships between proportions of carbohydrate intake as the % of total energy and diabetes complications in a nationwide cohort of Japanese patients with type 2 diabetes aged 40–70 years with hemoglobin A1c ≥6.5%. The analysis was of 1516 responders to a baseline dietary survey assessed by the Food Frequency Questionnaire based on food groups. Primary outcomes were times to overt nephropathy, diabetic retinopathy, and cardiovascular disease (CVD) after 8 years. Hazard ratios (HRs) for proportions of carbohydrate intake were estimated by Cox regression adjusted for confounders. High carbohydrate intake was significantly related to higher intakes of grain, fruits, and sweets/snacks and lower intakes of soybean and soy products, vegetables, seaweed, meat and processed meat, fish and processed fish, eggs, milk and dairy products, oil, and alcoholic beverages. During the eight-year follow-up, there were 81, 275, and 129 events of overt nephropathy, diabetic retinopathy, and CVD, respectively. After adjustment for confounders, HRs for complications in patients with carbohydrate intake in the second or third tertiles (51.0%–56.4% and ≥56.5%, respectively) compared with carbohydrate intake in the first tertile (<50.9%, referent) were analyzed. No significant associations were shown in the second and third tertiles relative to first tertile (overt nephropathy: 1.05 (95% Confidence Interval, 0.54–2.06) and 0.98 (0.40–2.44); diabetic retinopathy: 1.30 (0.90–1.88) and 1.30 (0.78–2.15); and CVD: 0.95 (0.55–1.63) and 1.37 (0.69–2.72)). By exploring potentially nonlinear relationships, trends for the incidence of diabetes complications according to proportions of carbohydrate intake were not clearly shown. Findings suggested that proportions of carbohydrate intake were not associated with the incidence of diabetes complications among type 2 diabetes patients in Japan.

Energy and nutrient intakes of Sri Lankan patients with type 2 diabetes mellitus: a cross-sectional survey

Background

Sri Lanka has a high prevalence of type 2 diabetes mellitus. Energy and macronutrient intakes of diabetic patients have not been previously studied in this population. We aimed to clarify the energy and nutrient intakes among a group of type 2 diabetic patients attending a tertiary care diabetes facility in Sri Lanka.

Methods

Nutritional and energy intake of 123 randomly selected patients with type 2 diabetes, aged 30–74 years was assessed using a 24-h dietary recall.

Results

The mean energy intake for all participants was 1438 (SD 412) Kcal/day. The mean proportions of total carbohydrate, protein and fat comprising total energy intake were 68.1, 11.5 and 20.2 % respectively. The mean carbohydrate intake of 249.7 g/day comprised 50 % of rice. The mean daily protein, fat and dietary fibre intake was 42.5, 33 and 18.1 g respectively with a major contribution from plant sources. There was no significant difference in energy and nutrient intakes among the male and female participants.

Conclusion

The present study provides the first pilot data on the energy and macronutrient intakes of diabetes patients in Sri Lanka. We clarified that these patients consumed an energy restricted, high-carbohydrate low fat diet compared to western diabetic patients. A larger nationwide dietary survey is recommended to confirm our findings.

Dietary intake in Japanese patients with type 2 diabetes: Analysis from Japan Diabetes Complications Study

AIMS/INTRODUCTION

Though there are many differences in dietary habits and in the metabolic basis between Western and Asian people, the actual dietary intake in Asian patients with diabetes has not been investigated in a nationwide setting, unlike in Western countries. We aimed to clarify dietary intake among Japanese individuals with type 2 diabetes, and identify differences in dietary intake between Japanese and Western diabetic patients.

MATERIALS AND METHODS

Nutritional and food intakes were surveyed and analyzed in 1,516 patients with type 2 diabetes aged 40-70 years from outpatient clinics in 59 university and general hospitals using the food frequency questionnaire based on food groups (FFQg).

RESULTS

Mean energy intake for all participants was 1737 ± 412 kcal/day, and mean proportions of total protein, fat, and carbohydrate comprising total energy intake were 15.7, 27.6 and 53.6%, respectively. They consumed a 'low-fat energy-restricted diet' compared with Western diabetic patients, and the proportion of fat consumption was within the suggested range that has been traditionally recommended in Western countries. As a protein source, consumption of fish (100 g) and soybean products (71 g) was larger than that of meat (50 g) and eggs (29 g). These results imply that dietary content and food patterns among Japanese patients with type 2 diabetes are quite close to those reported as suitable for prevention of obesity, type 2 diabetes, cardiovascular disease, and total mortality in Europe and America.

CONCLUSIONS

A large difference was shown between dietary intake by Japanese and Western patients. These differences are important to establish ethnic-specific medical nutrition therapy for diabetes.

High-intensity physical activity modulates diet effects on cerebrospinal amyloid-β levels in normal aging and mild cognitive impairment

We previously showed that amyloid-β 1-42 (Aβ(42)) levels in cerebrospinal fluid (CSF) were markedly altered in response to a 4-week dietary intervention in normal aging and mild cognitive impairment (MCI). Here, we re-examined the data to assess whether diet-induced effects on CSF Aβ(42) were modulated by high intensity physical activity (hi-PA). Normal older adults (n = 18, mean age = 68.6 ± 7.4 y) and adults with amnestic MCI (n = 23, mean age = 68.0 ± 6.5 y) received a low saturated fat/low glycemic index (LOW) diet or a high saturated fat/high glycemic index (HIGH) diet, and CSF levels of Aβ(42), tau, and IL-8 were measured at baseline and week 4. Pre-study activity levels were assessed using a 7-d questionnaire, and weekly duration of hi-PA was quantified. At baseline, increased hi-PA in normals predicted lower CSF levels of tau (r = -0.54, p = 0.020) and IL-8 (r = -0.70, p = 0.025). Diet-induced effects on CSF Aβ(42) during the intervention study were modulated by hi-PA, and the nature of this effect differed for normals and MCI (ANOVA, p = 0.039). That is, for normal adults, increased hi-PA attenuated the effects of the HIGH diet on CSF Aβ(42) whereas in MCI, increased hi-PA potentiated the effects of the LOW diet. Our results suggest that normal adults who engage in hi-PA are less vulnerable to the pathological effects of an unhealthy diet, while in MCI, the benefit of a healthy diet on Aβ modulation is greatest when paired with hi-PA. Exercise may thus interact with diet to alter pathological processes that ultimately modify risk of Alzheimer's disease.

Total energy intake may be more associated with glycemic control compared to each proportion of macronutrients in the korean diabetic population

BACKGROUND

Major macronutrients for energy intake vary among countries and cultures. Carbohydrates, including rice, are the major component of daily energy intake in Korea. The aim of this study was to examine the association of daily energy intake or each proportion of macronutrients, especially carbohydrates, with glycemic control in diabetic Koreans.

METHODS

A total of 334 individuals with diabetes (175 men, age 57.4±0.8 years; 159 women, age 60.9±0.9 years) who participated in the 2005 Korean National Health and Nutrition Examination Survey were examined. Glycemic control was categorized based on concentration of glycated hemoglobin (HbA1c; HbA1c ≤6.5%; 6.6% to 8.0%; ≥8.1%). Dietary intake was assessed by using a 24-recall item questionnaire.

RESULTS

High total energy intake was associated with poor glycemic control (HbA1c ≤6.5%, 1,824±75 kcal; 6.6% to 8.0%, 1,990±57 kcal; ≥8.1%, 2,144±73 kcal; P value for trend=0.002). Each proportion of protein, fat, or carbohydrate was not associated with glycemic control. Even after adjusting for several parameters, the association of daily energy intake with glycemic control still persisted.

CONCLUSION

Total energy intake may be more closely related to glycemic control than each proportionof macronutrients in Korean diabetics.

Optimal energy distribution of carbohydrate intake for Japanese elderly patients with type 2 diabetes: the Japanese Elderly Intervention Trial

AIM

In diet therapy for diabetes, optimal energy intake and the energy distribution of macronutrients (protein : fat : carbohydrate [PFC] energy ratio) are important. We aimed to clarify the correlation between the PFC energy ratio and metabolic parameters including glycated hemoglobin A1c (HbA1c) and triglycerides in Japanese elderly patients with type 2 diabetes mellitus aged 65 years or older.

METHODS

Participants were 1173 diabetic patients aged 65 years or older with serum HbA1c level of >/=7.4% enrolled in the Japanese Elderly Diabetes Intervention Trial (J-EDIT). The participants were divided into four groups by the percentage of total energy intake (%E) of carbohydrate (C1: less than 55%E, C2: 55%E or more and less than 60%E, C3: 60%E or more and less than 65%E, and C4: 65%E or more). Relations of %E of carbohydrate to HbA1c and other metabolic parameters, energy intake and nutritional intake were examined. Furthermore, the subjects were divided into four categories by HbA1c levels by quartile method (Q1: less than 7.90%, Q2: 7.90% or more and less than 8.30%, Q3: 8.30% or more and less than 8.80%, Q4: 8.80% or more). Relations of HbA1c to other metabolic parameters, energy intake and nutritional intake were examined.

RESULTS

The mean HbA1c levels in the four groups were C1: 8.40%, C2: 8.50%, C3: 8.41% and C4: 8.36% in men, and C1: 8.51%, C2: 8.47%, C3: 8.35% and C4: 8.52% in women, respectively. There were no significant differences and linear trend in HbA1c levels across groups. The mean triglyceride levels were in the range of 122-128 mg/dL in men from C1 to C3, although it was significantly higher in C4 (177 mg/dL). The mean triglyceride levels were in the range of 128-136 mg/dL in women from C1 to C3, although it was significantly higher in Q4 (150 mg/dL). Amounts of protein and fat intakes decreased with an increase of %E of carbohydrate, although amount of carbohydrate intake did not change significantly. As a result, %E of protein and fat, and energy intake decreased in both men and women with an increase in %E of carbohydrate. Among the four quartiles divided by HbA1c levels, there were no significant differences in energy intake and PFC energy ratio.

CONCLUSIONS

The present study suggests that, within the range studied, the carbohydrate energy ratio has no correlation with HbA1c levels. However, serum triglyceride levels increased and high-density lipoprotein cholesterol levels decreased significantly, with an increase of %E of carbohydrate in men, and the same tendencies were observed in women. Furthermore, in patients with 65%E or more of carbohydrate, serum triglyceride levels exceeded 150 mg/dL, which is the recommended treatment target for diabetic patients. These results suggest that the ideal %E of carbohydrate for Japanese elderly type 2 diabetes is less than 65. The lower limit of %E of carbohydrate could not be determined from the present study.

Cooking schools improve nutrient intake patterns of people with type 2 diabetes

OBJECTIVE

To determine whether cooking classes offered by the Cooperative Extension Service improved nutrient intake patterns in people with type 2 diabetes.

DESIGN

Quasi-experimental using pretest, posttest comparisons.

SETTING

Community locations including schools, churches, and senior centers.

PARTICIPANTS

One hundred seventeen people with type 2 diabetes, from diverse ethnic and socioeconomic backgrounds.

INTERVENTION

Series of classes for people with type 2 diabetes and their family members that incorporated Social Cognitive Theory tenets. The classes featured current nutrition recommendations for people with type 2 diabetes and hands-on cooking, where participants prepared and ate a meal together.

MAIN OUTCOME MEASURES

Three-day food records, completed prior to attending cooking schools and 1 month after, were used to measure changes in energy intake and selected nutrients.

ANALYSIS

Program efficacy was assessed using the Wilcoxon signed-rank test to compare differences between pre-training and post-training variables. ANCOVA was used to determine whether program efficacy was affected by sociodemographics.

RESULTS

Participants decreased (P < .05) intakes of energy, fat grams, percentage of calories from fat, saturated fat grams, cholesterol (mg), sodium (mg), and carbohydrate grams.

CONCLUSIONS AND IMPLICATIONS

Nutrition education incorporating hands-on cooking can improve nutrient intake in people with type 2 diabetes from diverse ethnic and socioeconomic backgrounds.

Lifestyle Interventions to Reduce Obesity and Diabetes

The majority of US adults are overweight or obese, which is a primary risk factor for type 2 diabetes and other chronic diseases. Recent advances in behavioral treatment of obesity have produced significant short- and long-term weight losses that reduce the risk of type 2 diabetes and cardiovascular disease. This article reviews key components of effective behavioral treatment interventions, including diet, exercise, and behavioral and psychosocial strategies. The authors review newer treatment modalities that may enhance dissemination (Internet, smartphone) and discuss applications to clinical practice. Practitioners face multiple barriers to effectively delivering lifestyle interventions in today’s health care setting but, nonetheless, remain powerful motivators in helping patients initiate and maintain weight loss efforts that reduce the risk of type 2 diabetes and other chronic diseases.

Low-carbohydrate diets: a matter of love or hate

Low-carbohydrate diets (LChD) have become very popular among the general population. These diets have been used to lose body weight and to ameliorate various abnormalities like diabetes, nonalcoholic fatty liver disease, polycystic ovary syndrome, narcolepsy, epilepsy, and others. Reports suggest that body weight reduction and glycemic control could be attained while following LChD. However, these advantages are more notably found in short periods of time consuming an LChD. Indeed, the safety and efficacy of the latter diets in the long term have not been sufficiently explored. In contrast to what has been proposed, other mentioned pathologies are not improved or are even worsened by carbohydrate restriction. Therefore, the aim of this review is to define the concept of LChD and to explain their clinical effects in the short and long term, their influence on metabolism, and the opinion of nutrition or health authorities. Finally, evincing the research gaps of LChD that are here exposed will later allow us to reach a consensus with regard to their utilization.

Diet intervention and cerebrospinal fluid biomarkers in amnestic mild cognitive impairment

OBJECTIVE

To compare the effects of a 4-week high-saturated fat/high-glycemic index (HIGH) diet with a low-saturated fat/low-glycemic index (LOW) diet on insulin and lipid metabolism, cerebrospinal fluid (CSF) markers of Alzheimer disease, and cognition for healthy adults and adults with amnestic mild cognitive impairment (aMCI).

DESIGN

Randomized controlled trial.

SETTING

Veterans Affairs Medical Center clinical research unit.

PARTICIPANTS

Forty-nine older adults (20 healthy adults with a mean [SD] age of 69.3 [7.4] years and 29 adults with aMCI with a mean [SD] age of 67.6 [6.8] years).

INTERVENTION

Participants received the HIGH diet (fat, 45% [saturated fat, > 25%]; carbohydrates, 35%-40% [glycemic index, > 70]; and protein, 15%-20%) or the LOW diet (fat, 25%; [saturated fat, < 7%]; carbohydrates, 55%-60% [glycemic index, < 55]; and protein, 15%-20%) for 4 weeks. Cognitive tests, an oral glucose tolerance test, and lumbar puncture were conducted at baseline and during the fourth week of the diet.

MAIN OUTCOME MEASURES

The CSF concentrations of β-amyloid (Aβ42 and Aβ40), tau protein, insulin, F2-isoprostanes, and apolipoprotein E, plasma lipids and insulin, and measures of cognition.

RESULTS

For the aMCI group, the LOW diet increased CSF Aβ42 concentrations, contrary to the pathologic pattern of lowered CSF Aβ42 typically observed in Alzheimer disease. The LOW diet had the opposite effect for healthy adults, ie, decreasing CSF Aβ42, whereas the HIGH diet increased CSF Aβ42. The CSF apolipoprotein E concentration was increased by the LOW diet and decreased by the HIGH diet for both groups. For the aMCI group, the CSF insulin concentration increased with the LOW diet, but the HIGH diet lowered the CSF insulin concentration for healthy adults. The HIGH diet increased and the LOW diet decreased plasma lipids, insulin, and CSF F2-isoprostane concentrations. Delayed visual memory improved for both groups after completion of 4 weeks of the LOW diet.

CONCLUSION

Our results suggest that diet may be a powerful environmental factor that modulates Alzheimer disease risk through its effects on central nervous system concentrations of Aβ42, lipoproteins, oxidative stress, and insulin.

A low carbohydrate Mediterranean diet improves cardiovascular risk factors and diabetes control among overweight patients with type 2 diabetes mellitus: a 1-year prospective randomized intervention study

BACKGROUND

The appropriate dietary intervention for overweight persons with type 2 diabetes mellitus (DM2) is unclear. Trials comparing the effectiveness of diets are frequently limited by short follow-up times and high dropout rates.

AIM

The effects of a low carbohydrate Mediterranean (LCM), a traditional Mediterranean (TM), and the 2003 American Diabetic Association (ADA) diet were compared, on health parameters during a 12-month period.

METHODS

In this 12-month trial, 259 overweight diabetic patients (mean age 55 years, mean body mass index 31.4 kg/m(2)) were randomly assigned to one of the three diets. The primary end-points were reduction of fasting plasma glucose, HbA1c and triglyceride (TG) levels.

RESULTS

194 patients out of 259 (74.9%) completed follow-up. After 12 months, the mean weight loss for all patients was 8.3 kg: 7.7 kg for ADA, 7.4 kg for TM and 10.1 kg for LCM diets. The reduction in HbA1c was significantly greater in the LCM diet than in the ADA diet (-2.0 and -1.6%, respectively, p < 0.022). HDL cholesterol increased (0.1 mmol/l +/- 0.02) only on the LCM (p < 0.002). The reduction in serum TG was greater in the LCM (-1.3 mmol/l) and TM (-1.5 mmol/l) than in the ADA (-0.7 mmol/l), p = 0.001.

CONCLUSIONS

An intensive 12-month dietary intervention in a community-based setting was effective in improving most modifiable cardiovascular risk factors in all the dietary groups. Only the LCM improved HDL levels and was superior to both the ADA and TM in improving glycaemic control.

Low-carbohydrate diet versus caloric restriction: effects on weight loss, hormones, and colon tumor growth in obese mice

Our objective was to compare the effects of a low-carbohydrate diet to a high-carbohydrate/calorie-restricted diet on weight loss, hormones, and transplanted colon tumor growth. Eighty male C57BL/6 mice consumed a diet-induced obesity regimen (DIO) ad libitum for 7 weeks. From Weeks 8 to 14, the mice consumed a 1) DIO diet ad libitum (HF); 2) low-carbohydrate diet ad libitum (LC); 3) high-carbohydrate diet ad libitum (HC); or 4) HC calorie restricted diet (HC-CR). MC38 cells were injected at Week 15. At the time of injection, the HC-CR group displayed the lowest body weight (25.5 +/- 0.57 g), serum insulin-like growth factor I (IGF-I; 135 +/- 56.0 ng/ml), and leptin (1.0 +/- 0.3 ng/ml) levels. This group also exhibited the longest time to palpable tumor (20.1 +/- 0.9 days). Compared to the HF group, the HC group exhibited lower body weight (39.4 +/- 1.4 vs. 32.9 +/- 0.7 g, respectively), IGF-I (604 +/- 44.2 vs. 243.4 +/- 88.9 ng/ml, respectively), and leptin (15.6 +/- 2.2 vs. 7.0 +/- 0.7 ng/ml, respectively) levels but similar tumor growth. IGF-I levels were lower in the LC group (320.0 +/- 39.9 ng/ml) than the HF group, but tumor growth did not differ. These data suggest LC diets do not slow colon tumor growth in obese mice.

A randomized clinical trial comparing low-glycemic index versus ADA dietary education among individuals with type 2 diabetes

OBJECTIVE

We compared the effects of a low glycemic index (GI) diet with the American Diabetes Association (ADA) diet on glycosylated hemoglobin (HbA1c) among individuals with type 2 diabetes.

METHODS

Forty individuals with poorly controlled type 2 diabetes were randomized to a low-GI or an ADA diet. The intervention, consisting of eight educational sessions (monthly for the first 6 mo and then at months 8 and 10), focused on a low-GI or an ADA diet. Data on demographics, diet, physical activity, psychosocial factors, and diabetes medication use were assessed at baseline and 6 and 12 mo. Generalized linear mixed models were used to compare the two groups on HbA1c, diabetic medication use, blood lipids, weight, diet, and physical activity.

RESULTS

Participants (53% female, mean age 53.5 y) were predominantly white with a mean body mass index of 35.8 kg/m(2). Although both interventions achieved similar reductions in mean HbA1c at 6 mo and 12 mo, the low-GI diet group was less likely to add or increase dosage of diabetic medications (odds ratio 0.26, P = 0.01). Improvements in high-density lipoprotein cholesterol, triacylglycerols, and weight loss were similar between groups.

CONCLUSION

Compared with the ADA diet, the low-GI diet achieved equivalent control of HbA1c using less diabetic medication. Despite its limited size, this trial suggests that a low-GI diet is a viable alternative to the ADA diet. Findings should be evaluated in a larger randomized controlled trial.

Rhythm of the beta-cell oscillator is not governed by a single regulator: multiple systems contribute to oscillatory behavior

Pulsatile insulin output, paralleled by oscillations in intracellular Ca(2+), reflect oscillating metabolism within beta-cells in response to secretory fuels. Here we question whether oscillatory periodicity is conserved or varied from stimulation to stimulation, whether glycolysis is essential for the manifestation of an oscillatory response, and if an environment of nutrient oversupply affects oscillatory regularity. We have determined that a beta-cell oscillatory Ca(2+) pattern is independent of the type of applied secretory fuel (glucose, methyl-pyruvate, or alpha-ketoisocaproate). In addition, single cells respond with the same pattern when repeatedly stimulated, regardless of the type of stimulatory fuel. Presence of substimulatory glucose is not necessary to obtain an oscillatory responses to methyl-pyruvate or alpha-ketoisocaproate. Glucose-6-phosphate, as a measure of glycolytic flux, is not detectable under these conditions. These data suggest that multiple systems, rather than a single enzyme component, can contribute to the beta-cell oscillatory behavior. Prolonged exposure to high levels of palmitate impaired oscillatory regularity in the individual beta-cells. This supports the hypothesis that a high-fat environment might contribute to loss of regular oscillatory pattern in diabetic subjects, acting, at least in part, at the level of the single beta-cell.