Vegetable Selection and Impact on Type 2 Diabetes
According to research presented by Dr. Anne Cathrine Thorup at the Aarhus University Hospital in Denmark, proper vegetable selection can can impact diabetes by reducing BMI, total body fat mass, HbA1c levels, and fasting glucose levels.
Type 2 diabetes mellitus is becoming a significant issue of concern. The number of cases has increased in prevalence around the world. The number of people with diabetes in 2015 was 415 million individuals, and the number is still expected to increase by 50% in 2040. Diet has been associated with the development of diabetes, and diet modification has been shown to aid in disease prevention and management. The Nordic diet consists of a high intake of fruits and vegetables, particularly root vegetables, cabbages, kale, berries, legumes, potatoes, nuts, fish, and livestock from game. Nutritionists and scientists have accepted the health benefits of root vegetables and cabbages in reducing type 2 diabetes, cardiovascular disease, and cancer. The benefits are exerted through phytochemicals found in root crops and cabbages. Modern consumers have developed a preference for more sweet-tasting vegetables at the expense of phytochemical content.
This trial sought to determine the difference between bitter and strong-tasting vegetables and their impact on patients with type 2 diabetes. Dr. Thorup and her colleagues submitted this research to the Journal of Nutrients to examine and summarize the benefits in this patient population. The study was a randomized controlled, parallel-designed trial over three months. A total of 92 people were enrolled in the study; however, 82 people completed the study. Eligible patients included those who had type 2 diabetes or were on an oral diabetic medication, 30 to 70 years of age, HbA1c between 5.5 and 7.3, and BMI of 23 to 40. Exclusion criteria included treatment with certain drugs, participation in other clinical trials, cardiovascular, liver, thyroid, or kidney disease, a disease that prevents diet restriction, substance abuse, pregnancy, and blood pressure higher than 160/110. Participants were randomized to one of three groups. In group A, participants consumed a basic Nordic diet, 120 grams daily of mild and sweet-tasting (MST) root vegetables and cabbages. In group B, participants consumed 500 grams daily of MST root vegetables and cabbages. In group C, participants consumed 500 grams of bitter and strong-tasting (BST) root vegetables and cabbages. The primary outcome of this trial was a change in insulin sensitivity. The secondary outcome was a change in glucose, HbA1c, insulin, lipids, blood pressure, and body composition. Participants were assessed two weeks before the beginning of the study and at weeks 0 and 12 to determine baseline characteristics. These characteristics were evaluated by ANOVA testing. Each difference determined between the groups was assessed by a t-test. In each case, statistical significance was indicated with a p-value of < 0.05. The minimum number of participants required to allow for 80% power was 23.
The results from this study showed that overall, the Nordic diet causes health improvements. However, BST vegetables had the most significant effect on insulin sensitivity, lipids, blood pressure, and body fat. With regard to the primary outcome, they observed a significant reduction in the oral glucose tolerance test, which evaluated insulin sensitivity. With regard to secondary outcomes, this study, although not designed to study weight loss, was noted as the participants losing a large amount of weight. Clinically, blood pressure was also reduced in both vegetable groups as well. It should be noted that this could be due to loss of weight that occurred in both groups due to a healthy diet, regardless of taste.
In conclusion, more studies should be done to determine how diet and vegetable selection can impact those with type 2 diabetes and other comorbidities. This study helped give more information on the positive effects of a high daily intake of root vegetables and cabbages on glucose and insulin in patients with type 2 diabetes. According to Thorup, “BST shows a more effective dietary strategy in treating and preventing type 2 diabetes compared to MST.” Strengths of this include examining an extensive range of outcomes, its methodical design, and randomization. Limitations of this study include it being a smaller trial. A larger study could be done to thoroughly examine the preventative potential of this diet and others.
- The number of people with diabetes in 2015 was 415 million individuals, and the number is still expected to increase by 50% in 2040.
- Diet has been associated with the development of diabetes, and diet modification has been shown to aid in disease prevention and management.
- Bitter and strong-tasting vegetables had the most significant effect on insulin sensitivity, lipids, blood pressure, and body fat.
References for “Vegetable Selection and Impact on Type 2 Diabetes”:
Thorup, Anne Cathrine, et al. “Strong and Bitter Vegetables from Traditional Cultivars and Cropping Methods Improve the Health Status of Type 2 Diabetics: A Randomized Control Trial.” Nutrients, vol. 13, no. 6, 2021, p. 1813., link
American Diabetes Association. “Diagnosis and classification of diabetes mellitus.” Diabetes care37.Supplement 1 (2014): S81-S90.
Drewnowski, Adam, and Carmen Gomez-Carneros. “Bitter taste, phytonutrients, and the consumer: a review.” The American journal of clinical nutrition 72.6 (2000): 1424-1435.
Kmeone Kingdom, MPH, PharmD Candidate, South College School of Pharmacy