Effects of total and green vegetable intakes on glycated hemoglobin A1c and triglycerides in elderly patients with type2 diabetes mellitus: The Japanese Elderly Intervention Trial

Abstract

Aim: Many reports have shown that vegetable intake is effective in inhibiting the onset and progression of diabetes mellitus, although the amount of vegetable intake required to be effective remains as unclear. The present study therefore aimed to clarify the relationship between the amount of vegetable intake and glycated hemoglobin A1c (HbA1c) and other metabolic parameters using male Japanese type2 diabetic patients aged 65years or older as subjects. Method: Participants were 417 male type2 diabetic patients aged 65years or older enrolled in the Japanese Elderly Diabetes Intervention Trial. Dietary intakes were measured by using the Food Frequency Questionnaires method. The patients were divided into five groups by their daily total vegetable intake (A1: ~100g, A2: 100~150g, A3: 150~200g, A4: 200~300g, A5: 300g~), and compared HbA1c and other metabolic parameters. Furthermore, the relationship between daily green vegetable intake and HbA1c and other metabolic parameters were examined among five groups divided by quintile methods. Results: There were significant decreases in HbA1c, triglycerides and waist circumference with an increase of total vegetable intake. A significant decrease of HbA1c levels was observed in patients with a daily total vegetable intake of 150g or more. Furthermore, there was a significant decrease of serum triglyceride levels in patients with a total vegetable intake of 200g or more. HbA1c levels showed a decreasing tendency with the increase of green vegetable intake, and HbA1c levels in the Q1 group (green vegetable intake: less than 40g) was significantly higher than those in the other four groups (anovaP=0.025). In addition, there were significant decreases of body mass index, triglyceride levels and waist circumference with the increase of green vegetable intake. Triglyceride levels decreased significantly from the Q3 group (green vegetable intake: 70g or more) to the Q5 group (green vegetable intake: 130g or more; anovaP=0.016). In the group with a lower intake of total vegetables and green vegetables, the protein energy ratio decreased significantly. As a result, the fat energy ratio and energy intake tended to increase with the decrease of total and green vegetable intakes. Furthermore, intake of grains, sweets and alcoholic beverages increased with the decrease of total vegetable intake. In contrast, intake of nuts, potatoes, sugar, legumes, fruit, seaweed and fish increased with the increase of total vegetable intake Conclusions: Daily total vegetable intake of 200g or more, and green vegetable intake of 70g or more correlated with improved control of HbA1c and triglyceride levels in elderly type2 diabetes patients through achieving a well-balanced diet. © 2012 Japan Geriatrics Society.