One of the most widespread diseases in the world, diabetes mellitus is a metabolic disorder that can have serious health consequences. A balanced vegan/vegetarian diet can reduce the risk of diabetes and is consistent with the principles of medical nutrition therapy.
What is diabetes?
Diabetes mellitus type 2 is caused by insulin resistance, which reduces the sensitivity of cells to insulin and leads to them absorbing less sugar (glucose), resulting in chronically elevated blood-sugar levels.1 A healthy person’s pancreas produces the hormone insulin when blood-sugar levels rise due to food intake. Ingested food is broken down into simple sugars (glucose) after which insulin stimulates the delivery of glucose to the cells, where it is metabolised. About 90% of diabetics suffer from type 2 diabetes. Type 1 diabetes, on the other hand, is an autoimmune disease in which there is a lack of insulin because the immune system destroys the insulin-producing beta cells.2 3
Incidence of diabetes
According to World Health Organization estimates, diabetes affected about 8.5% of the world’s adult population in 2014. In 2019, about 1.5 million deaths worldwide were attributed to diabetes.4 Yet type 2 diabetes is often curable with a healthy lifestyle and a diet based on the principles of medical nutrition therapy.5
Causes of diabetes
The risk of developing type 2 diabetes is determined by a combination of genetic and metabolic factors. Obesity, an unhealthy diet, lack of exercise, and smoking can all increase the risk of becoming diabetic.6 More than 80% of people who develop obesity also develop type 2 diabetes.7 Due to diabetics’ insulin resistance, their bodies no longer respond adequately to insulin, which leads to a rise in their blood-sugar levels. The pancreas tries to counteract this by producing more insulin – an overproduction that can lead to beta-cell fatigue. When the beta-cells are exhausted or fail, they can no longer produce enough insulin to transport glucose out of the bloodstream. Age is a key risk factor for type 2 diabetes, while childbirth is a risk factor for gestational diabetes.8
Typical symptoms of diabetes
Diabetes often develops gradually and the warning signs are not always clear. A typical symptom of diabetes is increased thirst, which is caused by excess glucose in the bloodstream, which draws fluid from body tissue. Another symptom is a strong urge to urinate. Diabetics are also often exhausted because sugar is missing from their muscle and organ cells, causing a lack of energy. The lack of glucose in the cells, which serves as fuel, means that diabetics tire more quickly and are constantly hungry. Weight loss is another symptom of diabetes. Since people afflicted with the disease cannot metabolise glucose into energy, the body uses up reserves stored in fat and muscle mass. Blurred vision, poor wound healing, or constant infections can also indicate diabetes.9
Diabetes diagnosis in the doctor’s office
If you think you might be diabetic, you should see a doctor. A diagnosis can be made by testing the fasting blood-glucose level. Values below 100 mg/dl are considered normal. A blood-sugar level of 100 to 125 mg/dl indicates the preliminary stage of type 2 diabetes. At this stage, also called prediabetes, diabetes can be prevented with a healthy lifestyle. A bloodtest result of 126 mg/dl or more confirms the diagnosis of diabetes.10
Diabetes risks and long-term damage
Having diabetes increases the risk of cardiovascular diseases such as heart attacks or strokes by a factor of two to three. As a result of the reduced blood flow, nerve damage can occur, usually starting in the hands and feet. It can manifest as numbness, pain, or a burning sensation. Poorly controlled blood sugar can even lead to a loss of feeling in the extremities. Poor blood circulation means that even minor injuries heal poorly and can lead to serious infections, which in turn can make amputations necessary. Digestive problems and kidney damage, as well as hearing and skin problems, are some of the late-stage effects of untreated or poorly treated diabetes.11
Prevention and therapy: diet for diabetes
In order to minimise the risk of diabetes, one should choose a diet that contains little saturated fat and sugar, and a lot of dietary fibre. With an increased intake of dietary fibre, carbohydrates are absorbed more slowly into the blood, allowing blood-sugar levels to rise more slowly. High-fibre fruit and vegetables should therefore be consumed daily. In addition, wholegrain bread, wholemeal pasta, etc. are preferable to white-flour products. Several studies show that a high consumption of wholegrain products can reduce the risk of type 2 diabetes and ensure a lower and slower rise in blood-sugar levels. A healthy weight and sufficient exercise can prevent this metabolic disease while at the same time lowering blood-sugar levels.12 13 14
Depending on the severity of the diabetes, it might need to be treated with medication. Patients generally inject themselves with insulin to regulate their blood sugar. There are short-acting and long-acting insulin preparations. If the body is given insulin, it makes sense to check blood-sugar levels several times a day, since exercise, diet, alcohol, illness, and other medications can all affect blood-sugar levels.15
The food plate is endorsed by various nutrition societies and national governments and provides a simple guide to making healthy food choices. The composition of the plate corresponds to current scientific knowledge regarding the health effects of what we eat and drink. In the following article, ProVeg discusses the vegan version of the food plate.
Regular meat consumption can increase diabetes risk
More and more studies point to the link between regular meat consumption and an increased risk of developing type 2 diabetes.16 17 18 An Oxford University study of over 474,000 people found that daily consumption of 70 grams of unprocessed red meat (such as beef or pork) and processed meat (such as bacon, sausages, or ham) increased the risk of developing type 2 diabetes by 30%. Daily consumption of 30 grams of poultry meat increased the risk by 17%. The influence of other lifestyle factors was taken into account in this calculation.19 A review evaluating 28 studies – all of which examine the connection between meat consumption and type 2 diabetes risk – came to similar conclusions.20
Preventing diabetes with a vegan-vegetarian diet
The benefits of a wholefood vegan/vegetarian diet in preventing type 2 diabetes are now well established. An evaluation of the Adventist Health Study, which included over 96,000 participants, showed that the incidence of type 2 diabetes increased gradually with the consumption of animal-based products and that vegans, followed by vegetarians, were less likely to be affected by diabetes.21 The so-called Rotterdam Study, with over 6,700 participants, investigated the influence of a plant-based diet on the risk of type 2 diabetes compared to an animal-based diet. It concluded that a more plant-based diet can reduce the risk of insulin resistance, prediabetes, and type 2 diabetes.22 Various other studies have come to similar conclusions, with the vegan groups always having the lowest risk of developing diabetes.23
Vegans eat exclusively plant-based food. In other words, they do not eat animals or animal-based products. But there is much more to a vegan way of life than diet. Whether it’s caring for animals, the environment, or one’s own health, there is a multitude of reasons to choose a vegan lifestyle. ProVeg explains more about vegan diets.
Treating diabetes with a vegan-vegetarian diet
The benefits of treating type 2 diabetes with a wholefood, plant-based diet have already been confirmed in numerous studies.24 2006 saw the publication of the results of one of the first large randomised clinical trials to treat diabetics with a vegan diet. The study participants were randomly assigned to receive either a low-fat vegan diet or a diet based on the American Diabetes Association (ADA) guidelines, which emphasises a low-fat mixed diet. After 22 weeks, 43% of the vegan group and 26% of the ADA group were able to reduce their diabetes medication. In addition, the body weight of the vegan group was reduced by an average of 6.5 kg, while that of the ADA group decreased by only 3.1 kg.25 26
An academic overview study found that diabetics can lower their HbA1c levels with a vegetarian or vegan diet.27 HbA1c is a laboratory value used to determine the development of blood-glucose levels over the previous 8-12 weeks. It is particularly important for diabetics to be able to draw conclusions about the quality of their blood-glucose regulation. The higher the percentage, the higher the blood-glucose levels, which need to be kept low.28
Other benefits of a plant-based diet in the prevention and treatment of diabetes
A plant-based diet consisting mainly of vegetables, fruits, legumes, and whole grains, as well as nuts and seeds, is considered to be particularly advantageous for the prevention and treatment of type 2 diabetes. Such a diet contains only small amounts of saturated fatty acids and is rich in unsaturated fatty acids, which help to lower blood sugar levels.29 In addition to olive and canola oil, particularly good sources of omega-3 fatty acids include walnuts, hemp seeds, and flaxseeds, as well as the oils made from them. Furthermore, fibre intake is higher in a purely plant-based diet than in other diets, and is associated with lower blood-glucose levels and improved insulin sensitivity.30 31 In addition, fibre keeps you feeling full for a long time and thus helps with weight management.32 In addition to fruit and vegetables, good sources of dietary fibre include whole grains such as wheat, oats, rye, and spelt, and legumes such as lentils, peas, beans, and lupins.
ProVeg tips for the prevention and treatment of diabetes
There are several dietary strategies that can be used to prevent or lower high blood sugar. A vegan/vegetarian diet has tremendous health benefits in both cases:
- A healthy body weight and sufficient exercise reduce the risk of diabetes, while also helping to regulate blood sugar in cases where the disease is already present.
- A wholefood, plant-based diet is particularly suitable for diabetics because it contains only small amounts of saturated fatty acids and instead provides valuable dietary fibre.
- Unsaturated and polyunsaturated fatty acids, which are found in walnuts, hemp seeds, and flax seeds, as well as the oils made from them, lower blood-sugar levels.
- Whole-grain products and legumes keep you feeling full for a long time and cause blood sugar to rise more slowly, so that blood-sugar levels remain generally constant.
- If you experience symptoms such as increased thirst or urination, weight loss, or frequent infections, or if you have multiple risk factors, you should see a doctor to determine whether you have diabetes.
These are general nutrition guidelines. If you have concerns about your diet, please talk to your doctor about seeing a dietitian. Discussing the use of supplements with a health professional will help to ensure that they are suitable for you. Never stop taking prescribed medications without first talking to your doctor.
|↑1||American Diabetes Association (2021): Understanding Insulin Resistance. Online at: https://www.diabetes.org/healthy-living/medication-treatments/insulin-resistance [08.06.2021]|
|↑2||International Diabetes Federation (2020): Type 2 diabetes. Online at: https://www.idf.org/aboutdiabetes/type-2-diabetes.html [08.06.2021]|
|↑3||Mayo Clinic (2021): Type 2 diabetes. Online at: https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/symptoms-causes/syc-20351193 [08.06.2021]|
|↑4, ↑11||World Health Organization (2021): Diabetes. Available at https://www.who.int/news-room/fact-sheets/detail/diabetes [08.06.2021]|
|↑5||American Diabetes Association (2021): Life doesn’t end with type 2 diabetes. Available at https://www.diabetes.org/diabetes/type-2 [08.06.2021]|
|↑6, ↑12||World Health Organization (2021): Diabetes. Available at https://www.who.int/news-room/fact-sheets/detail/diabetes [08.06.2021]|
|↑7||Apovian C.M., Okemah J., O’Neil P.M. (2019): Body Weight Considerations in the Management of Type 2 Diabetes. Adv Ther 36, 44–58. https://doi.org/10.1007/s12325-018-0824-8|
|↑8, ↑9, ↑13, ↑15||Mayo Clinic (2021): Type 2 diabetes. Online at: https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/symptoms-causes/syc-20351193 [08.06.2021]|
|↑10||American Diabetes Association (2021): Diagnosis. Available at https://www.diabetes.org/a1c/diagnosis [08.06.2021]|
|↑14||International Diabetes Federation (2020): Diabetes prevention. Available at https://www.idf.org/aboutdiabetes/prevention.html [08.06.2021]|
|↑16, ↑19||Papier K., Fensom G.K., Knuppel A. et al. (2021): Meat consumption and risk of 25 common conditions: outcome-wide analyses in 475,000 men and women in the UK Biobank study. BMC Med 19, 53 (2021). https://doi.org/10.1186/s12916-021-01922-9|
|↑17||Talaei M., Wang Y.L., Yuan Y.M., Pan A., Koh W.P. (2017): Meat, Dietary Heme Iron, and Risk of Type 2 Diabetes Mellitus: The Singapore Chinese Health Study, American Journal of Epidemiology, Volume 186, Issue 7, Pages 824–833, https://doi.org/10.1093/aje/kwx156|
|↑18||Barnard, Neal et al. (2014): Meat consumption as a risk factor for type 2 diabetes. Nutrients vol. 6,2 897-910. 21 Feb. 2014, doi:10.3390/nu6020897|
|↑20||Yang X, Li Y, Wang C, et al. (2020): Meat and fish intake and type 2 diabetes: dose–response meta-analysis of prospective cohort studies. Diabetes Metab. 2020 Oct;46(5):345-352. doi: 10.1016/j.diabet.2020.03.004. Epub 2020 Apr 14. PMID: 32302686.|
|↑21||Olfert M.D., Wattick R.A. (2018): Vegetarian Diets and the Risk of Diabetes. Curr Diab Rep. 2018;18(11):101. Published 2018 Sep 18. doi:10.1007/s11892-018-1070-9|
|↑22||Chen Z, Zuurmond MG, van der Schaft N, Nano J, Wijnhoven HAH, Ikram MA, Franco OH, Voortman T. (2018): Plant versus animal based diets and insulin resistance, prediabetes and type 2 diabetes: the Rotterdam Study. Eur J Epidemiol. 2018 Sep;33(9):883-893. doi: 10.1007/s10654-018-0414-8. Epub 2018 Jun 8. PMID: 29948369; PMCID: PMC6133017.|
|↑23||Lee, Y., Park, K. (2017): Adherence to a Vegetarian Diet and Diabetes Risk: A Systematic Review and Meta-Analysis of Observational Studies. Nutrients. 2017 Jun 14;9(6):603. doi: 10.3390/nu9060603. PMID: 28613258; PMCID: PMC5490582.|
|↑24||Olfert M.D., Wattick R.A.(2018): Vegetarian Diets and the Risk of Diabetes. Curr Diab Rep. 2018;18(11):101. Published 2018 Sep 18. doi:10.1007/s11892-018-1070-9|
|↑25||Barnard ND, Cohen J, Jenkins DJ, Turner-McGrievy G, Gloede L, Jaster B, Seidl K, Green AA, Talpers S (2006): A low-fat vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes. Diabetes Care. 2006 Aug; 29(8):1777-83.|
|↑26||McMacken M, Shah S. (2017): A plant-based diet for the prevention and treatment of type 2 diabetes. J Geriatr Cardiol. 2017;14(5):342-354. doi:10.11909/j.issn.1671-5411.2017.05.009|
|↑27||Yokoyama, Y., Barnard, N. D., Levin, S. M., Watanabe, M. (2014): Vegetarian diets and glycemic control in diabetes: a systematic review and meta-analysis. Cardiovasc Diagnosis Ther [Internet]. AME Publications; 2014 Oct [cited 2017 Oct 5];4(5):373–82. Online at: http://www.ncbi.nlm.nih.gov/pubmed/25414824 [09.06.2021]|
|↑28||American Diabetes Association (2021): Understanding A1C. Available at https://www.diabetes.org/a1c [09.06.2021]|
|↑29||Imamura, F., Micha, R., Wu, J. H. Y., de Oliveira Otto, M. C., Otite, F. O., Abioye, A. I. et al. (2016): Effects of saturated fat, polyunsaturated fat, monounsaturated fat, and carbohydrate on glucose-insulin homeostasis: a systematic review and meta-analysis of randomised controlled feeding trials. Ma RCW, editor. PLoS Med [Internet]. 2016 Jul 19 [cited 2017 Oct 9];13(7):e1002087. Online at: http://www.ncbi.nlm.nih.gov/pubmed/27434027 [08.05.2018]|
|↑30||Barnard, N. D., Katcher, H. I., Jenkins, D. J., Cohen, J., Turner-McGrievy, G. (2009): Vegetarian and vegan diets in type 2 diabetes management. Nutr Rev [Internet]. 2009 May [cited 2017 Oct 9];67(5):255–63. Online at: http://www.ncbi.nlm.nih.gov/pubmed/19386029 [08.05.2018]|
|↑31||Barnard, N. D., Katcher, H. I., Jenkins, D. J., Cohen, J., Turner-McGrievy, G. (2009): Vegetarian and vegan diets in type 2 diabetes management. Nutr Rev [Internet]. 2009 May [cited 2017 Oct 9];67(5):255–63. http://www.ncbi.nlm.nih.gov/pubmed/19386029|
|↑32||Lattimer, J. M., Haub, M. D. (2010): Effects of dietary fiber and its components on metabolic health. Nutrients [Internet]. 2010 Dec 15 [cited 2017 Sep 13];2(12):1266–89. Online at: http://www.ncbi.nlm.nih.gov/pubmed/22254008 [08.05.2018]|