Diabetes is defined as “a serious life-long health condition that occurs when the body’s ability to respond to the hormone insulin is impaired, resulting in abnormal carbohydrate metabolism and elevated levels of blood sugar.
By this definition and with the assertion that it is a lifelong condition, it would suggest that there is no cure, however in the time before diabetes becomes symptomatic, there is a long period where blood sugar levels are raised but full diabetes is not diagnosed. 70% of people with this condition, known as pre-diabetes go on to develop full type 2 diabetes but progressing from pre-diabetes to diabetes isn’t inevitable (1). Halting the progression of diabetes and becoming part of the 30% is a cure of types and moving into the 30% has been shown to be perfectly possible with the right diet and lifestyle choices.
Being active and doing exercise has been shown to increase the insulin sensitivity of cells, reversing some of the effects of diabetes. Moderate, high intensity, high intensity interval training and strength training have all independently been shown to reduce insulin resistance and the levels of blood sugar in pre-diabetic adults (2,3,4,5,6,7). And, you don’t even have to rush around or join a gym, a ten to fifteen minute stroll after main meals has been shown to lower postprandial blood sugar and have a greater effect on blood levels than exercise at other times (8), curbing blood sugar spikes for up to twelve hours (9).
Not everyone who develops full type 2 diabetes is overweight but the majority are. Losing weight does improve risk (10) and the more you lose the better (11). Excess visceral fat, which is fat around the middle of the body, is particularly bad (12,13,14,15). This is because this includes fat around and within body organs. Scientists have identified that losing just 1gram of fat from around or within your pancreas can radically change diabetic symptoms and return insulin secretion to normal levels (16). When looking to lose weight, there maybe particular benefit in concentrating on portion size. Controlling portion size and being careful to limit the amount you eat at any one time lowers blood sugar and insulin levels (17).
This is an area where research is improving all the time and there is increasing evidence that some foods or the nutrients within them actually help the body control blood sugar and insulin levels. The list of foods is extensive, ranging from cinnamon (18) to salmon (19) but there are a number of themes that are easy to follow. The first is to eat more fibre. The latest UK Diet and Nutrition Survey published in 2016 showed that fibre intake is far below recommended levels in all age groups (20). Increasing fibre is one reason why we all should increase fruit and vegetable consumption. Studies in a wide variety of people have shown increasing fibre helps reduce blood glucose and insulin response. Fibre slows the speed with which sugar is absorbed (21) and also supports beneficial gut microflora, which in turn improve carbohydrate metabolism and energy storage, lowering blood sugar (22). Gut microflora are also the reason for the strong links between yoghurt consumption and low diabetes risk. Eating any fermented dairy products, which boost beneficial gut microflora, has been shown to modulate sugar metabolism and improve symptoms (23). The other big group of foods that are beneficial are ones containing high levels of polyphenols. Polyphenols are natural phytonutrients found in plants. Pretty much all foods nicknamed ‘functional’ or ‘super-foods’ contain high levels of polyphenols and diets high in polyphenols have been shown to protect against diabetes (24). Coffee and tea contain polyphenols and both (but particularly coffee) have been linked with lower diabetes risk (25). The green tea polyphenol epigallocatechin gallate (EGCG) has been shown to reduce blood sugar release from the liver and increase insulin sensitivity and anthocyanins found in all dark blue/purple fruits and vegetables (blueberry, blackcurrant, cherry, plum, aubergine, red cabbage) have been found to transform the effect of a high sugar meal and also lower overall risk (26).
Michael Pollan, author of “In defence of Food: An Eaters Manifesto “ and a Professor at University of California is widely quoted for his assertion that the answer to health is to “eat food, not too much, mostly plants”. When it comes to diabetes prevention and ‘cure’, he may have a very good point.
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(1) Nathan et al 2007. Impaired Fasting Glucose and Impaired Glucose Tolerance – Implications for care. Diabetes Care 30(3):753-759
(2) Renders et al 2014. Effects of exercise intensity on postprandial improvement in glucose disposal and insulin sensitivity in prediabetic adults. J Clin Endocrinol Metabolism 99(1):220-228.
(3) Ryan et al 2014. Aerobic exercise and weight loss reduce vascular markets of inflammation and improve insulin sensitivity in obese women. J Am Geriatric Soc 62(4):607-614
(4) Lanai et al 2015. Short-term HIIT and Fat max training increase aerobic and metabolic fitness in men with class II and III Obesity. Obesity 23(10):1987-94
(5) Geirsdottir et al 2012. Effect of 12-week resistance exercise program on body composition, muscle strength, physical function and Glucose metabolism in healthy, insulin-resistant and diabetic elderly Icelanders. J Gerontol A Biol Sci Med Sci 67(11):1259-1265
(6) Eikenberg et al 2016. Prediabetes Phenotype Influences Improvements in Glucose Homeostasis with resistance training. PLoS One 11(2):e0148009.doi:10.1371/Journal.pone.0148009.
(7) Malin et al 2013. Pancreatic β-cell function increases in a linear dose-response manner following exercise training in adults with prediabetes. Am J Physiol Endocrinol Metabolism 305(10):E1248-54 doi:10.1152/ajpendo.00260.2013
(8) Reynolds et al 2016. Advice to walk after meals is more effective for lowering postprandial glycaemia in type 2 diabetes mellitus than advice that does not specify timing : a randomised crossover study. Diabetologia 59(12):2572-2578
(9) DiPietro et al 2013. Three 15-minute Bouts of Moderate Post Meal Walking Significantly Improves 24h Glycemic Control in Older People at Risk for Impaired Glucose Tolerance. Diabetes Care 36(10):3262-3268
(10) Maruthur et al 2013. Early response to preventive strategies in the diabetes prevention program. J Gen Intern Med 28(12):1629-1636
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(12) Neeland et al 2012. Dysfunctional adiposity and the risk of prediabetes and type 2 diabetes in obese adults. JAMA 308(11):1150-1059
(13) Jung et al 2016. Visceral Fat Mass Has Stronger Associations with Diabetes and Prediabetes than Other Anthropometric Obesity Indicators among Korean Adults. Yonsei Med 57(3): 674-680
(14) Item & Konrad 2012. Visceral fat and metabolic inflammation:the portal theory revisited. Obes Rev 13(sup2):30-39
(15) Kim et al 2014. A protein profile of visceralapipose tissues linked to early pathogenesis of type 2 diabetes mellitus. Mol Cell Proteomics 13(3):811-22
(16) Stevens et al 2015. Weight loss decreases excess pancreatic triacylglycerol specifically in type 2 diabetes. Diabetes Care doi:10.2337/dc15-0750
(17) Melanson et al 2012. Body Composition, dietary composition and components of metabolic syndrome in overweight and obese adults after a 12 week trial on dietary treatments focused on portion control, energy density or glycemic index.
(18) Allen et al 2013. Cinnamon use in type 2 diabetes: an updated systematic review and meta-analysis. Ann Farm Med 11(5):452-459
(19) Niinisto et al 2017. Fatty Acid status in infancy associated with the risk of type 1 diabetes-associated autoimmunity. Diabetologia 60(7):1223-1233.
(21) Weickert & Pfeiffer 2008. Metabolic effect of dietary fibre consumption and prevention of diabetes. J Nutr 138(3):439-42
(22) Cani and Delzenne 2007. Gut microflora as a target for energy and metabolic homeostasis. Current Opinion in Clin Nutr and Met Care 10:729-734.
(23) Salad-Salvado et al 2017. Yogurt and diabetes: overview of recent observational studies. J Nutr doi :10.3945/in.117.248229
(24) Xiao and Hogger 2015. Dietary polyphenols and type 2 diabetes:current insights and future perspectives. Current Med Chem 22(1):23-38.
(25) Muley et al 2012. Coffee to reduce risk of type 2 diabetes? A systematic review. Current Diabetes Rev 8(3):162-8.
(26) Guy & Ling 2015. The update of anthocynins on obesity and type 2 diabetes:experimental evidence and clinical perspectives. Rev Endocrinol Metab Disord 16(1):1-13.