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Nuts and Heart Health

How do you halve your risk of developing heart disease? By eating a handful of nuts (30g) five or more times a week! Tree nuts such as almonds, Brazil nuts, cashews, chestnuts, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts are packed full of beneficial nutrients for heart health. Eating nuts regularly, as part of a diet low in saturated fat and a lifestyle that includes exercise, is one tasty prescription to help lower blood cholesterol levels and maintain a healthy heart. Here’s how…

Eat nuts regularly

Studies show enjoying a handful of nuts every day can significantly reduce your risk of developing heart disease or dying from it.1–5 Even those who eat nuts once a week have less heart disease than those who don’t eat any nuts.1 It seems frequent nut consumption is associated with lower levels of inflammatory markers,6, 7 which may partially explain the lower risk of both heart disease and diabetes.1–5, 8 In general you can achieve an 8.3% reduction in risk of death from coronary heart disease with each weekly serving of nuts.9 A daily handful of nuts also reduces mortality by 20% adding more years to your life.10, 11

Why nuts are so heart healthy

Nuts contain a variety of nutrients and other bioactive substances that contribute to lowering the risk of heart disease and controlling cholesterol:

Rich source of healthy fats12 Nuts are a healthy high-fat food in a fat-phobic world, but there’s no need to avoid all fats in the diet. Eating a variety of nuts will help provide the right balance of healthy fats in your daily eating plan. Healthy fats are monounsaturated or polyunsaturated fats which can help regulate blood cholesterol.13 Nuts high in monounsaturated fat include macadamias, hazelnuts, pecans, almonds, cashews and pistachios. Nuts high in polyunsaturated fat include walnuts, pine nuts and Brazil nuts.12

Contains plant omega-3s12 Plant omega-3s are a type of polyunsaturated fat found in walnut, pecans, hazelnuts and macadamias. These nuts are one of the few plant sources of omega-3s. This short chain omega-3, called alpha-linoleic acid (ALA), has heart health properties.14 Long chain omega-3s are mostly found in fish and seafood and are also required for heart health.

Regulates cholesterol – A meta analysis combining the results of 25 nut and cholesterol-lowering studies found that around two handfuls of nuts – 67g on average each day – significantly reduced total and LDL cholesterol by 5% and 7% respectively.15 This is supported by two other meta analyses specifically on almonds and walnuts which also support eating at least a handful a day to significantly lower total and LDL cholesterol.16, 17

Natural source of plant sterols12 These are substances which can help to lower cholesterol levels in the blood by reducing cholesterol re-absorption in the intestine.18 Mixed nuts in general contain around 126mg plant sterols per 100g.12

Reduces cholesterol oxidation – A traditional Mediterranean diet (TMD) including 30g per day of nuts has been shown to reduce LDL cholesterol oxidation when compared to a lower-fat diet.19–21 Oxidation of LDL cholesterol is a key step in atherosclerosis – the blocking and hardening of arteries. Another study found this effect particularly with almonds, Brazil nuts and pistachios.22

Reduces inflammation – Studies have shown that eating nuts has antiinflammatory effects.6, 7 Antioxidants and other phytochemicals play an important role in reducing inflammation. Chronic inflammation is thought to cause many chronic diseases such as heart disease and diabetes.6, 7, 23

Rich source of antioxidants and phytochemcials – Nuts contain a variety of antioxidants including vitamin E, selenium, copper, manganese plus phytochemicals such as flavonoids, resveratrol and ellagic acid.12, 24–26 These protective plant compounds maintain the health of blood vessels, reduce the risk of congested arteries and have an antiinflammatory action.24–27 Just like fruits and vegetables, the specific content of plant antioxidant compounds varies from nut to nut especially nuts with skins – so eating a variety of nuts is key.

A source of arginine12 Nuts contain arginine, an amino acid building block of protein which is converted to nitric oxide in the body. Nitric oxide causes blood vessels to relax and remain elastic. Hardening of the arteries and blood clotting can lead to heart disease.20, 28

Contains fibre12 All nuts contribute fibre to the diet. There are two types of fibre in foods – soluble and insoluble fibre. Soluble fibre helps reduce blood cholesterol by reducing cholesterol reabsorption in the intestine, excreting it from the body.29 Insoluble fibre helps maintain a healthy bowel function. Nuts with skins are particularly high in fibre.

Helps those with overweight and diabetes – Eating a daily serve of nuts as part of a healthy diet does not lead to weight gain as once thought. Nut protein, fat and fibre are thought to play a role in appetite control. Nuts are also good for those with pre-diabetes, insulin resistance and Type 2 Diabetes. Adding nuts to a meal with carbohydrates can slow the rise in blood glucose after the meal and improve insulin sensitivity.30

Part of a Mediterranean Diet – A daily handful of nuts was incorporated into the five year PREDIMED Mediterranean diet study which found benefits for heart health, Type 2 diabetes, metabolic syndrome, brain health among other conditions, in the 7500 older people studied.31


References

  • Fraser GE, et al. A possible protective effect of nut consumption on risk of coronary heart disease. Arch Intern Med 1992;152:1416-24.
  • Hu FB, Stampfer MJ. Nut consumption and Risk of Coronary Heart Disease: A Review of Epidemiologic. Evidence Current Athero Reports 1999;1:205-210.
  • Ellsworth JL, et al. Frequent nut intake and risk of death from coronary heart disease and all causes in postmenopausal women: the Iowa Women’s Health Study. Nutr Metab Cardiovasc Dis 2001;11(6):372-7
  • Albert CM, et al. Nut consumption and decreased risk of sudden cardiac death in the Physician’s Health Study. Arch Intern Med 2002;162(12):1382-7.
  • Blomhoff R, et al. Health benefits of nuts: potential role of antioxidants. Brit J Nutr 2007;96(SupplS2):S52-S60.
  • Salas-Salvadó J, et al. The effect of nuts on inflammation. Asia Pac J Clin Nutr 2008;17(Suppl 1):333-6.
  • Casas-Agustench P, et al. Effects of one serving of mixed nuts on serum lipids, insulin resistance and inflammatory markers in patients with the metabolic syndrome. Nutr Metab Cardiovasc Dis 2011;21(2):126-35.
  • 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 Clin Nutr. 2014 Jul;100(1):278-88.
  • Sabaté J, Wien M. Nuts, blood lipids and cardiovascular disease. Asia Pac J Clin Nutr 2010;19(1):131-136.
  • Luu H, et al Prospective Evaluation of the Association of Nut/Peanut Consumption With Total and Cause-Specific Mortality. JAMA Intern Med. 2015 May;175(5):755-66
  • Bao Y, et al. Association of nut consumption with total and cause-specific mortality. N Engl J Med. 2013 Nov 21;369(21):2001-11.
  • Nuts for Life. 2016 Nutrient Composition of Tree Nuts. Sydney: Nuts for Life; 2016.
  • Hooper L, et al. Reduced or modified dietary fat for preventing cardiovascular disease. Cochrane Database Syst Rev. 2012 May 16;5:CD002137. doi: 10.1002/14651858.CD002137.pub3.
  • Pan A, et al. α-Linolenic acid and risk of cardiovascular disease: a systematic review and meta-analysis. Am J Clin Nutr. 2012 Dec;96(6):1262-73.
  • Sabaté, et al. Nut consumption and blood lipid levels: a pooled analysis of 25 intervention trials. Arch Intern Med 2010;170(9):821-7.
  • Phung OJ, et al. Almonds have a neutral effect on serum lipid profiles: A Meta-Analysis of randomized trials. JADA 2009;109(5): 865-873 (letter to the editor JADA 2009;109(9):1521-22.)
  • Banel DK, Hu FB. Effects of walnut consumption on blood lipids and other cardiovascular risk factors: a meta-analysis and systematic review. Am J Clin Nutr 2009;90(1):56-63.
  • Ras RT, et al. LDL-cholesterol-lowering effect of plant sterols and stanols across different dose ranges: a meta-analysis of randomised controlled studies. Br J Nutr. 2014 Jul;112(2):214-9.
  • Fito M, et al. Effect of a traditional Mediterranean diet on lipoprotein oxidation: a randomized controlled trial. Arch Intern Med 2007;167(11):1195-1203.
  • Ros E. Nuts and novel biomarkers of cardiovascular disease. Am J Clin Nutr 2009;89(5):1649S-56S.
  • 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;138(9):1746S-1751S.
  • López-Uriarte P, et al Nuts and oxidation: a systematic review. Nutr Rev 2009;67(9):497-508.
  • Sears B. Anti-inflammatory diets for obesity and diabetes. J Am Coll Nutr 2009;28 (Suppl):482S-491S.
  • Kris-Etherton PM et al. Nuts and their bioactive constituents: effects on serum lipids and other factors that affect disease risk. Am J Clin Nutr 1999;70(suppl):504S-511S.
  • Kornsteiner M, et al. Tocopherols and total phenolics in 10 different nut types. Food Chemistry 2005;98(2):381-387.
  • Gentile C, et al. Antioxidant activity of Sicilian pistachio (Pistacia vera L. var. Bronte) nut extract and its bioactive components. J Agric Food Chem 2007;55(3):643-8.
  • Xiao Z, et al. Flavonoids health benefits and their molecular mechanism. Mini Rev Med Chem 2011;Jan 11. [Epub ahead of print].
  • Blum A, Miller H. The effects of L-arginine on atherosclerosis and heart disease. Int J Cardiovasc Intervent
    1999;2(2):97-100.
  • Threapleton, DE et al. Dietary fibre intake and risk of cardiovascular disease: systematic review and meta-analysis. BMJ. 2013 Dec 19;347:f6879.
  • Nuts for Life. Nut Report – Nuts and the Big Fat Myth – the positive role for nuts in weight management. 2012. Nuts for Life https://www.nutsforlife.com.au/resources/literature-reviews-summaries/
  • Nuts for Life. PREDIMED – A five year Mediterranean and mixed nuts diet study from Spain. 2015 Nuts for Life
    https://www.nutsforlife.com.au/resources/literature-reviews-summaries/

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