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Nuts and diabetes

Around 8% or 1 in 12 Australians aged 18 years and over have either diabetes or pre-diabetes1. Tree nuts such as almonds, Brazil nuts, cashews, chestnuts, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts have a wide variety of nutritional benefits which are not only important for those with diabetes, but also those wanting to reduce the risk of developing type 2 diabetes.

Got type 2 diabetes or at risk of it? Here’s why you should eat nuts regularly:

Reduce your risk of type 2 diabetes – Of the five large population studies to look for a link between eating nuts and a reduced risk of diabetes three found this positive link while two found no association at all.2–6 The largest study of almost 84,000 women found that eating nuts can reduce the risk of developing type 2 diabetes (T2D).2 Women who ate a 28g serve of nuts (a handful) five or more times per week had a 27% lower risk of diabetes compared to those who never or rarely ate nuts.2 The 4 year PREDIMED Mediterranean Diet study found those following the Med diet enriched with 30g of nuts a day reduced their risk of diabetes by 52% compared to a reduced fat diet and regardless of changes in body weight and physical activity.7 A recent meta analysis of 6 studies found a regular 30g handful of nuts reduce the risk of type 2 diabetes by 13%.8

Improve blood glucose levels – studies have found that including nuts in meals can reduce the rise in blood glucose levels following the meal.9–11 High blood glucose after eating is common in people with diabetes and contributes to diabetesrelated complications (involving damage to eyes, kidneys, nerves and blood vessels).12 In general the majority of research shows consuming nuts, in a healthy diet, will either help improve glycemic control or have a neutral effect.

Prevent heart disease – people with diabetes are more than twice as likely to die from cardiovascular disease than those with normal blood glucose.13 Studies have shown that eating a handful of nuts most days can reduce the risk of heart disease by 30–50%.14 This can be attributed to the healthy fats, dietary fibre, plant sterols, arginine and antioxidant vitamins and minerals (including vitamin E) nuts contain.15 One study found women with T2D who ate at least five serves of nuts per week reduced their risk of heart disease by almost half.16

Improve blood fats – people with diabetes are more likely to have abnormal blood fat levels, including higher ‘bad’ LDL cholesterol and triglycerides, and lower ‘good’ HDL cholesterol.17 High blood cholesterol is a risk factor for heart disease. Eating nuts regularly can improve blood fats, particularly by lowering LDL cholesterol.18 The majority of research studies in those with diabetes or metabolic syndrome found positive effects of nut consumption (29–108g/day) for at least one marker of cardiovascular risk compared to a control diet including blood cholesterol and triglycerides, blood pressure, lipid oxidation, inflammatory markers and endothelial function.

Lower blood pressure risk (BP) – an important Australian study of people with diabetes found that compared to those with normal blood glucose levels, people with diabetes were more than three times as likely to suffer from high BP.17 In another study young adults who were followed for 15 years found that those who ate the most nuts reduced their risk of developing high blood pressure by 15%.19

Control your weight – carrying extra weight is a major risk factor for T2D and can make managing your diabetes more difficult. A major Australian study also found that almost three times as many people with diabetes were obese compared to those with normal glucose levels.17 The good news? Eating nuts may help with weight management. A meta analysis of 33 studies has shown that diets enriched with nuts (30–100g/day) do not increase body weight, body mass index, or waist circumference in controlled clinical trials.20 Studies have found that incorporating nuts (28–108g/day) into the diet either leads to no weight gain or a small weight loss.21–23

Why are nuts so good for type 2 diabetes?

  • Low glycemic index (GI) – while not a high carbohydrate food, nuts have a GIlowering effect – they reduce the overall GI of a meal.9–11 A low-GI diet has been shown to reduce the risk of T2D and help in its management.24
  • Rich source of healthy fats – nuts contain mostly healthy monounsaturated and polyunsaturated fats, plus are low in saturated fat and trans fats.25 Replacing saturated and trans fats with unsaturated fats improves insulin sensitivity and reduces T2D risk.26–28
  • A good source of fibre – diets high in fibre may help manage diabetes and weight and can reduce the risk of developing type 2 diabetes.29
  • A natural source of plant sterols which can help to lower cholesterol levels by reducing cholesterol reabsorption in the intestine.30 31
  • High in potassium and low in sodium, providing benefits for blood pressure and heart health.29
  • A good source of arginine – this amino acid helps keep blood vessels elastic and helps prevent blood clotting.32 Hardening of the arteries and blood clotting can lead to heart disease.
  • A rich source of magnesium – a higher intake of magnesium is linked with a reduced risk of type 2 diabetes.33 34
  • High in vitamin E – an essential vitamin and antioxidant which can help protect against heart disease. Some studies suggest that vitamin E may protect against diabetes complications such as


References

  • Australian Bureau of Statistics 43640DO005_20112012 Australian Health Survey: Biomedical Results for Chronic Diseases, 2011-12 – Australia.www.abs.gov.au
  • Jiang R, et al. Nut and peanut butter consumption and risk of type 2 diabetes in women. JAMA 2002;288(20):2554–2560. Comment Parker ED, et al. Nut consumption and risk of type 2 diabetes. JAMA 2003;290(1):38-9.
  • Pan A, et al., Walnut consumption is associated with lower risk of type 2 diabetes in women. J Nutr. 2013;143(4):512-8.
  • Villegas R, et al. Legume and soy food intake and the incidence of type 2 diabetes in the Shanghai Women’s Health Study. Am J ClinNutr. 2008;87(1): 162-167.
  • Ibarrola-Jurado N, et al. Cross-sectional assessment of nut consumption and obesity, metabolic syndrome and other cardiometabolic risk factors: the PREDIMED study. PLoS One. 2013;8(2):e57367.
  • Kochar J, et al. Nut consumption and risk of type II diabetes in the Physicians’ Health Study. Eur J ClinNutr. 2010;64(1):75-9.
  • Salas-Salvado J, et al., Reduction in the incidence of type 2 diabetes with the Mediterranean diet: results of the PREDIMED-Reus nutrition intervention randomized trial.Diabetes Care. 2011;34(1):14-9.
  • Afshin A, et al. Consumption of nuts and legumes and risk of incident ischemic heart disease, stroke, and diabetes: a systematic review and meta-analysis. Am J ClinNutr.2014 Jul;100(1):278-88.
  • Jenkins DJ, et al. Almonds decrease postprandial glycemia, insulinemia, and oxidative damage in healthy individuals. J Nutr. 2006;136(12):2987-92.
  • Parham M, et al. Effects of pistachio nut supplementation on blood glucose in patients with type 2 diabetes: a randomized crossover trial. Rev Diabet Stud. 2014 Summer;11(2):190-6.
  • Kendall CW, et al. The glycemic effect of nut-enriched meals in healthy and diabetic subjects. NutrMetabCardiovasc Dis. 2011 Jun;21Suppl 1:S34-9.
  • Aryangat AV and J.E. Gerich. Type 2 diabetes: postprandial hyperglycemia and increased cardiovascular risk. Vasc Health Risk Manag. 2010;24;6:145-55.
  • Barr ELM, et al. Risk of cardiovascular and all-cause mortality in individuals with diabetes mellitus, impaired fasting glucose, and impaired glucose tolerance: The Australian Diabetes, Obesity, and Lifestyle Study (AusDiab). Circulation 2007;116(2):151-157.
  • Sabaté J, Wien M. Nuts, blood lipids and cardiovascular disease. Asia Pac J ClinNutr. 2010;19(1):131-6. 15. Kris-Etherton PM, et al. The role of tree nuts and peanuts in the prevention of coronary heart disease: multiple potential mechanisms. J Nutr. 2008 Sep;138(9):1746S-1751S.
  • Kris-Etherton PM, et al. The role of tree nuts and peanuts in the prevention of coronary heart disease: multiple
    potential mechanisms. J Nutr. 2008 Sep;138(9):1746S-1751S.
  • Li TY, et al. Regular consumption of nuts is associated with a lower risk of cardiovascular disease in women with type 2 diabetes. J Nutr. 2009;6:6.
  • Magliano DJ, et al. Glucose indices, health behaviors, and incidence of diabetes in Australia. Diabetes Care 2008; 31(2):267-272.
  • Sabate J, et al. Nut consumption and blood lipid levels: a pooled analysis of 25 intervention trials. Arch Intern Med. 2010; 170(9):821-7.
  • Steffen LM, et al. Associations of plant food, dairy product, and meat intakes with 15-y incidence of elevated blood pressure in young black and white adults: the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Am J ClinNutr. 2005; 82(6):1169-77.
  • Flores-Mateo G, et al Nut intake and adiposity: meta-analysis of clinical trials. Am J ClinNutr. 2013;Jun;97(6):1346–55.
  • Mattes R.D. and M.L. Dreher. Nuts and healthy body weight maintenance mechanisms. Asia Pac J ClinNutr. 2010;19(1):137–41.
  • Natoli, S. and P. McCoy, A review of the evidence: nuts and body weight. Asia Pac J ClinNutr. 2007;16(4):588-97.
  • Mattes RD, et al. Impact of peanuts and tree nuts on body weight and healthy weight loss in adults. J Nutr. 2008;138(9):1741S-1745S.
  • Thomas D, et al. Low glycaemic index, or low glycaemic load, diets for diabetes mellitus. Cochrane Database Syst Rev. 2009(1):CD006296.
  • Nuts for Life, 2016 Nutrient Composition of Tree Nuts. 2016; Nuts for Life: Sydney.
  • Riccardi, G et al. Dietary fat, insulin sensitivity and the metabolic syndrome. ClinNutr. 2004;23(4):447-56.
  • Riserus, U. Fatty acids and insulin sensitivity. CurrOpinClinNutrMetab Care. 2008;11(2):100-5.
  • Riserus, U et al. Dietary fats and prevention of type 2 diabetes. Prog Lipid Res. 2009;48(1):44-51.
  • NHMRC. Micronutrients and Dietary Fibre papers. Nutrient Reference Values for Australia and New Zealand 2006. Available at https://www.nrv.gov.au/disease/macronutrient_dietary.htm
  • Ostlund RE. Regulation of cholesterol absorption by phytosterols. CurrAtheroscler Rep. 2006; 8(6):487-91.
  • Ostlund RE. Phytosterols and cholesterol metabolism. CurrOpinLipidol. 2004;15(1):37-41.
  • Coates AM, et al. Edible nuts and metabolic health. CurrOpinLipidol. 2007;18(1):25-30.
  • Schulze MB, et al. Fiber and magnesium intake and incidence of type 2 diabetes: a prospective study and meta-analysis. Arch Intern Med. 2007;167(9):956-65.
  • Larsson SC, et al. Magnesium intake and risk of type 2 diabetes: a meta-analysis. J Intern Med. 2007;262(2):208-14.
  • Bursell SE, et al. High-dose vitamin E supplementation normalizes retinal blood flow and creatinine clearance in patients with type 1 diabetes. Diabetes Care 1999; 22(8):1245-1251
  • Tütüncü NB, et al. Reversal of defective nerve conduction with vitamin E supplementation in type 2 diabetes: a preliminary study. Diabetes Care 1998; 21(11):1915-1918.
  • Ceriello A, et al. Vitamin E reduction of protein glycosylation in diabetes. New prospect for prevention of diabetic complications? Diabetes Care 1991;14(1):68-72.

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