A study supported by the National Institute for Health Research (NIHR) Leicester Biomedical Research Centre (BRC) – a partnership between Leicester’s Hospitals, the University of Leicester and Loughborough University – and NIHR Applied Research Collaboration East Midlands (ARC EM) into the effects of a vegan diet in people with or at risk of developing type 2 diabetes has concluded that a plant-based lifestyle may help control blood glucose levels.
Researchers on the ‘Plant Your Health’ study looked at whether a vegan diet could reduce the production of TMAO as well as improve blood sugar control in the body, and therefore reduce the risk of symptoms of type 2 diabetes. TMAO (or trimethylamine N-oxide) is a molecule produced when food, particularly from animal sources, is broken down in the gut. Its presence is associated with an increased risk of heart disease, which is often linked to type 2 diabetes.
The study followed 23 individuals who either had or were at risk of developing type 2 diabetes, or whose weight was defined as clinically obese. Participants were given a full health check, including TMAO, blood sugar and cholesterol levels. They were then asked to swap their regular meals with like-for-like vegan equivalents over a period of eight weeks and encouraged to keep their physical activity the same.
The researchers found that on average TMAO levels in participants almost halved after just one week, and remained relatively steady at eight weeks. However, when participants switched back to their regular diets at the end of the study, TMAO levels had rebounded to their original levels four weeks later.
Blood glucose levels were also found to decrease at weeks one and eight.
Professor Tom Yates, a professor of physical activity and sedentary behaviour at the University of Leicester, and co-author on the study, said: “Recent research into the causes of type 2 diabetes has found a strong association between a molecule in the blood called TMAO and increased risk of heart disease. TMAO is produced as a byproduct of how certain foods are broken down in the gut and has been associated with an increase in the buildup of plaque in the arteries, which can lead to heart problems.
“Research has found that TMAO is particularly linked to animal products in the diet such as red meat, eggs and dairy. Due to the increased risk of patients with type 2 diabetes also developing heart disease, research suggests that there is a connection between diet, type 2 diabetes and heart functioning.”
Dr Stavroula Argyridou, a registered dietitian who conducted the research, said: “Our findings suggest that a vegan diet could be an effective strategy for reducing TMAO and blood sugar levels in individuals with or at high risk of type 2 diabetes.
“This means it could provide a suitable alternative to a conventional diet that is usually recommended for people with type 2 diabetes. We would need to widen participation to see if these initially promising results are replicated in larger groups of patients, over a longer period of time, and with a control group.”
Diabetes rates are on the increase across all age groups, largely due to lifestyle choices such as low levels of physical activity, or being overweight or obese as a result of consuming more energy than we use. Type 2 diabetes represents a serious clinical and financial burden to the NHS. £8.8bn is spent for the treatment of this disease and its complications. Financial estimation studies project an indirect cost of £20 billion in 2035/2036 to the NHS budget. Therefore a range of suitable treatments is needed to prevent, manage and treat the condition in growing numbers of people.
The paper, ‘Evaluation of an 8-week vegan diet on plasma Trimethylamine-N-Oxide and post-challenge glucose in adults with dysglycemia or obesity’ is published in the Journal of Nutrition on 30 March 2021.