Influence of fat and carbohydrate proportions on the metabolic profile in patients with type 2 diabetes: a meta-analysis

Effect of consumption of dried California mission figs on lipid concentrations

BACKGROUND

Figs are a rich source of soluble fiber. We evaluated the effect of consuming dried California Mission figs on serum lipids in hyperlipidemic adults.

METHODS

In a crossover trial men and women aged 30-75 years with elevated low-density lipoprotein cholesterol (100-189 mg/dl) were randomized to add dried California Mission figs (120 g/day) to their usual diet for 5 weeks or eat their usual diet for 5 weeks, then crossed over to the other condition for another 5 weeks. Six 24-hour dietary recalls were obtained.

RESULTS

Low- and high-density lipoprotein cholesterol and triglyceride concentrations did not differ between usual and figs-added diets (Bonferroni-corrected p > 0.017), while total cholesterol tended to increase with fig consumption (p = 0.02). Total cholesterol increased in participants (n = 41) randomized to usual followed by figs-added diet (p = 0.01), but remained unchanged in subjects (n = 42) who started with figs-added followed by usual diet (p = 0.4). During the figs-added diet, soluble fiber intake was 12.6 ± 3.7 versus 8.2 ± 4.1 g/day in the usual diet (p < 0.0001). Sugar intake increased from 23.4 ± 6.5 to 32.2 ± 6.3% of kcal in the figs-added diet (p < 0.0001). Body weight did not change (p = 0.08).

CONCLUSIONS

Daily consumption of figs did not reduce low-density lipoprotein cholesterol. Triglyceride concentrations were not significantly changed despite an increase in sugar intake.

Reduced or modified dietary fat for preventing cardiovascular disease

BACKGROUND

Reduction and modification of dietary fats have differing effects on cardiovascular risk factors (such as serum cholesterol), but their effects on important health outcomes are less clear.

OBJECTIVES

To assess the effect of reduction and/or modification of dietary fats on mortality, cardiovascular mortality, cardiovascular morbidity and individual outcomes including myocardial infarction, stroke and cancer diagnoses in randomised clinical trials of at least 6 months duration.

SEARCH STRATEGY

For this review update, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE, were searched through to June 2010. References of Included studies and reviews were also checked.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised with appropriate control group, 2) intention to reduce or modify fat or cholesterol intake (excluding exclusively omega-3 fat interventions), 3) not multi factorial, 4) adult humans with or without cardiovascular disease, 5) intervention at least six months, 6) mortality or cardiovascular morbidity data available.

DATA COLLECTION AND ANALYSIS

Participant numbers experiencing health outcomes in each arm were extracted independently in duplicate and random effects meta-analyses, meta-regression, sub-grouping, sensitivity analyses and funnel plots were performed.

MAIN RESULTS

This updated review suggested that reducing saturated fat by reducing and/or modifying dietary fat reduced the risk of cardiovascular events by 14% (RR 0.86, 95% CI 0.77 to 0.96, 24 comparisons, 65,508 participants of whom 7% had a cardiovascular event, I(2) 50%). Subgrouping suggested that this reduction in cardiovascular events was seen in studies of fat modification (not reduction - which related directly to the degree of effect on serum total and LDL cholesterol and triglycerides), of at least two years duration and in studies of men (not of women). There were no clear effects of dietary fat changes on total mortality (RR 0.98, 95% CI 0.93 to 1.04, 71,790 participants) or cardiovascular mortality (RR 0.94, 95% CI 0.85 to 1.04, 65,978 participants). This did not alter with sub-grouping or sensitivity analysis.Few studies compared reduced with modified fat diets, so direct comparison was not possible.

AUTHORS' CONCLUSIONS

The findings are suggestive of a small but potentially important reduction in cardiovascular risk on modification of dietary fat, but not reduction of total fat, in longer trials. Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates. The ideal type of unsaturated fat is unclear.

Nutrition therapy and the management of obesity and diabetes: an update

Diabetes and obesity have each become a national health crisis in recent years. The number of people who have diabetes and prediabetes continues to grow with a predicted number of 336 million people worldwide with type 2 diabetes by 2030. The prevalence of diabetes has risen in parallel with the increased prevalence of obesity. The optimal nutrition therapy for the treatment of both diabetes and obesity remains controversial. Health care practitioners are no longer solely prescribing the conventional low-fat, higher-carbohydrate diet approach that was used for over a decade. Lower-carbohydrate, higher-fat, or higher-protein diets are now being viewed as equally or sometimes more effective treatment plans for diabetes and obesity. In addition, there are other aspects of diet beyond macronutrient composition that are currently being investigated. This article will summarize research conducted over the past 2 years examining medical nutrition therapy for diabetes and obesity. It will also describe the unique challenges that come with treating this patient population.

The evidence for medical nutrition therapy for type 1 and type 2 diabetes in adults

This article reviews the evidence and nutrition practice recommendations from the American Dietetic Association's nutrition practice guidelines for type 1 and type 2 diabetes in adults. The research literature was reviewed to answer nutrition practice questions and resulted in 29 recommendations. Here, we present the recommendations and provide a comprehensive and systematic review of the evidence associated with their development. Major nutrition therapy factors reviewed are carbohydrate (intake, sucrose, non-nutritive sweeteners, glycemic index, and fiber), protein intake, cardiovascular disease, and weight management. Contributing factors to nutrition therapy reviewed are physical activity and glucose monitoring. Based on individualized nutrition therapy client/patient goals and lifestyle changes the client/patient is willing and able to make, registered dietitians can select appropriate interventions based on key recommendations that include consistency in day-to-day carbohydrate intake, adjusting insulin doses to match carbohydrate intake, substitution of sucrose-containing foods, usual protein intake, cardioprotective nutrition interventions, weight management strategies, regular physical activity, and use of self-monitored blood glucose data. The evidence is strong that medical nutrition therapy provided by registered dietitians is an effective and essential therapy in the management of diabetes.

A comparative study of diet in good and poor glycemic control groups in elderly patients with type 2 diabetes mellitus

BACKGROUND

Identification of dietary patterns is important for glycemic management in elderly patients with type 2 diabetes mellitus (T2DM).

METHODS

Elderly T2DM patients (> 65 years of age, n = 48) were categorized based on their concentration of glycated hemoglobin (HbA(1c)). Subjects with HbA(1c) levels below 7% were placed in the good control (GC) group and those with HbA(1c) levels equal to or above 8% were placed in the poor control (PC) group. Anthropometric data, blood parameters, and dietary intake records were compared between the groups. Statistical analysis included Student's t-test, chi-square test, and Pearson correlation coefficient test.

RESULTS

Anthropometric data, including body mass index (24.7 ± 2.9 kg/m(2)), did not differ between the GC and PC groups. Significant abnormalities in blood glucose levels (P < 0.01), lean body mass (P < 0.01), and plasma protein and albumin levels (P < 0.05, P < 0.01) were found in the PC group. In contrast to the GC group, the PC group depended on carbohydrate (P = 0.014) rather than protein (P = 0.013) or fat (P = 0.005) as a major source of energy, and had a lower index of nutritional quality for nutrients such as protein (P = 0.001), and all vitamins and minerals (P < 0.001, 0.01, or 0.05 for individual nutrients), except vitamin C, in their usual diet. Negative correlations between HbA(1c) levels and protein (r = -0.338, P < 0.05) or fat (r = -0.385, P < 0.01) intakes were also found.

CONCLUSIONS

Healthcare professionals should encourage elderly diabetic patients to consume a balanced diet to maintain good glycemic control.

Using the glycemic index in diabetes management

Consider carbohydrate quality to achieve blood glucose control.

The role of diet and lifestyle in primary, secondary, and tertiary diabetes prevention: a review of meta-analyses

Prevention of diabetes is crucial to lowering disease incidence, and thus minimizing the individual, familial, and public health burden. The purpose of this review is to gather current information from meta-analyses on dietary and lifestyle practices concerning reduction of risk to develop type 2 diabetes. Low glycemic index dietary patterns reduce both fasting blood glucose and glycated proteins independent of carbohydrate consumption. Diets rich in whole-grain, cereal high fiber products, and non-oil-seed pulses are beneficial. Whereas, frequent meat consumption has been shown to increase risk. Regarding non-alcoholic beverages, 4 cups/day of filtered coffee or tea are associated with a reduced diabetes risk. In contrast, the consumption of alcoholic beverages should not exceed 1-3 drinks/day. Intake of vitamin E, carotenoids, and magnesium can be increased to counteract diabetes risk. Obesity is the most important factor accounting for more than half of new diabetes' cases; even modest weight loss has a favorable effect in preventing the appearance of diabetes. Also, physical exercise with or without diet contributes to a healthier lifestyle, and is important for lowering risk. Finally, there is a positive association between smoking and risk to develop type 2 diabetes. As far as secondary and tertiary prevention is concerned, for persons already diagnosed with diabetes, there is limited evidence of the effectiveness of diet or lifestyle modification on glycemic control, but further studies are necessary.

Dietary strategies for patients with type 2 diabetes in the era of multi-approaches; review and results from the Dietary Intervention Randomized Controlled Trial (DIRECT)

Dietary intervention is recognized as a key component in prevention and management of type 2 diabetes (T2DM) and the debate persists: which dietary strategy is most effective. In the Dietary Intervention Randomized Controlled Trial (DIRECT) 322 moderately obese participants were randomized for 2 years to one of three diet groups: low-fat, Mediterranean and low-carbohydrate. Differential effects were observed in the sub-group of patients with T2DM at 24 months: participants randomized to the Mediterranean diet, which had the highest intake of dietary fibers and unsaturated to saturated fat ratio, achieved greater significant improvements in fasting plasma glucose and insulin levels. Patients who were randomized to the low-carbohydrate diet, which had the minimal intake of carbohydrates, achieved a significant reduction of hemoglobin A1C. Although improvements were observed in all groups, the low-fat diet was likely to be less beneficial in terms of glycemic control and lipid metabolism. Interpretation of results from different studies on dietary strategies may be complex since there is often no consistency in diet compositions, calorie restriction, intensity of intervention, dietary assessment or extent of adherence in the trial. Nevertheless, it seems that low fat restricted calorie diets are effective for weight loss and are associated with some metabolic benefits; however, some recent trials have shown that low carbohydrate diets are as efficient in inducing weight loss and in some metabolic measures such as serum triglycerides and HDL-cholesterol may be even superior to low fat diets. When addressing the issue of diet quality rather than quantity applying the glycemic index may have some added benefits. Furthermore special features of the Mediterranean diet have apparent additional favorable effects for patients with T2DM.