Effectiveness of medical nutrition therapy provided by dietitians in the management of non-insulin-dependent diabetes mellitus: a randomized, controlled clinical trial. Improved metabolic control by Ipomoea batatas (Caiapo) is associated with increased adiponectin and decreased fibrinogen levels in type 2 diabetic subjects. [Effectiveness of treatment with metformin in patients with type 2 diabetes mellitus poorly controlled with insulin treatment].
To assess the effect of medical nutrition therapy (MNT) provided by dietitians on medical and clinical outcomes for adults with non-insulin-dependent diabetes mellitus (NIDDM), and to compare MNT administered according to practice guidelines nutrition care (PGC) to MNT administered with basic nutrition care (BC).
                A prospective, randomized, controlled clinical trial of two levels of MNT on metabolic control in persons newly diagnosed with or currently under treatment for NIDDM was conducted at diabetes centers in three states (Minnesota, Florida, and Colorado). BC consisted of a single visit with a dietitian; PGC involved an initial visit with a dietitian followed by two visits during the first 6 weeks of the study period. Data were collected at entry to the study and at 3 and 6 months.
                Results are reported for 179 men and women aged 38 to 76 years: 85 assigned randomly to BC and 94 to PGC. This represents 72% of the 247 subjects enrolled. An additional 62 adults with NIDDM at one site who had no contact with a dietitian were identified as a nonrandom comparison group.
                Medical outcome measures included fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), and serum lipid levels. Clinical outcomes included weight, body mass index, waist-to-hip ratio, and changes in medical therapy.
                Initial analysis of the discrete variables was done using the chi 2 statistic with Yates' correction. Initial analysis of continuous variables was done by analysis of variance. The changes in variables between time periods were analyzed by paired t test, and comparisons between groups were analyzed using a t test for independent groups.
                At 6 months, PGC resulted in significant improvements in blood glucose control as indicated by FPG and HbA1c levels and BC resulted in significant improvements in HbA1c level. Participants assigned to the PGC group had a mean FPG level at 6 months that was 10.5% lower than the level at entry, and those in the BC group had a 5.3% lower value. Among subjects who had diabetes for longer than 6 months, those who received PGC had a significantly better HbA1c level at 3 months compared with those receiving BC. The comparison group showed no improvement in glycemic control over a comparable 6 months. PGC subjects had significant improvements in cholesterol values at 6 months, and subjects in both the PGC and the BC groups had significant weight loss.
                MNT provided by dietitians resulted in significant improvements in medical and clinical outcomes in both the BC and PGC groups and is beneficial to persons with NIDDM. Persons with a duration of diabetes longer than 6 months tended to do better with PGC than with BC. Because of the upward trend in glucose levels after 3 months, ongoing MNT by dietitians is important for long-term metabolic control. The extract of the white-skinned sweet potato Ipomoea batatas (Caiapo) has been shown to ameliorate glucose control by improving insulin sensitivity in patients with type 2 diabetes mellitus (T2DM). The present study was designed to further evaluate its mode of action on insulin sensitivity over an extended period of time as well as the effects on fibrinogen and other markers of low-grade inflammation.
                In this randomized trial, 27 patients with T2DM on diet only received 4 g of Caiapo daily for 5 months; 34 patients placebo. Before and after therapy, insulin sensitivity [oral glucose insulin sensitivity (OGIS), as glucose clearance from oral glucose tolerance test], parameters of diabetes control, lipids, plasma adiponectin, high-sensitivity C-reactive protein (hs-CRP) and fibrinogen were measured.
                Following Caiapo, we observed an increase in OGIS (293 +/- 15 vs. 321 +/- 12 ml/m(2)/min, p = 0.0072) and adiponectin (5.97 +/- 0.65 to 6.63 +/- 0.70 microg/ml, p = 0.013), while fibrinogen decreased from 3.83 +/- 0.16 to 3.64 +/- 0.18 mg/ml (p = 0.02). This was associated with an improvement in glycated haemoglobin (HbA1c: 6.46 +/- 0.12 vs. 6.25 +/- 0.11%, p = 0.008), fasting glucose (138 +/- 4 vs. 128 +/- 5 mg/dl, p = 0.039) and triglycerides (2.36 +/- 0.22 vs. 2.07 +/- 0.25 mmol/l, p = 0.032). Body weight, lipid levels and hs-CRP were not altered. No changes were observed in the placebo group except for HbA1c, which significantly increased from 6.25 +/- 0.10 to 6.50 +/- 0.12% (p = 0.0001).
                This study confirms the beneficial effects of Caiapo on glucose and HbA1c control in patients with T2DM after 5 months follow-up. Improvement of insulin sensitivity was accompanied by increased levels of adiponectin and a decrease in fibrinogen. Thus, Caiapo can be considered as natural insulin sensitizer with potential antiatherogenic properties. Combined treatment with insulin plus metformin could be a good alternative to improve the glycemic control in patients with type 2 diabetes mellitus poorly controlled with insulin therapy. We retrospectively studied 21 obese insulin-treated type 2 diabetic patients with deficient metabolic control (HbA1c 9.2 +/- 1.2%) who were treated with metformin for a minimum of 8 months. After 4 months of treatment, a significant decrease in the percentage of HbA1c was observed (delta HbA1c -1.07 +/- 1.12%; p < 0.01), with maintained values since then. Non changes in body weight or insulin requirement were noted. Our results suggest that the addition of metformin to insulin treatment is a safe and effective strategy for the improvement of glycemic control among obese type 2 diabetic patients.
There is insufficient evidence to recommend sweet potato for type 2 diabetes mellitus. Improvement in trial methodology as well as addressing the issues of standardization and the quality control of preparations of other varieties of sweet potato are required. For medical nutritional therapy, further observational trials and RCTs evaluating the effects of sweet potato are needed to guide any recommendations in clinical practice.