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Continuing education and the APD program

  1. Top of page
  2. Continuing education and the APD program
  3. Introduction
  4. Answers
  5. References

This quiz is an ideal activity for APD members to include in your CPD log, where it relates to personal learning goals. Record the time taken, to the nearest hour, to complete the quiz and any associated research.

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This quiz has been prepared by Lisa Yates, Adv APD and Liz Munn, APD, dietitians working for Nuts for Life—a health education initiative funded by the Australian Tree Nut Industry and with Australian Government matched funding for R&D activities through Horticulture Australia. Correspondence should be addressed to Lisa Yates, Program Manager, Nuts for Life at admin@nutsforlife.com.au

Introduction

  1. Top of page
  2. Continuing education and the APD program
  3. Introduction
  4. Answers
  5. References

Nuts have been widely consumed in many different cultures since prehistoric times.1 Nuts are nutrient dense and help improve the quality of the diet.2 Nuts were included in the modelling for the recent Australian foundation and total diets3 which suggests that for foundation diets, between 2 and 14 serves of nuts a week is required, where a serve is 30 g and is dependent on age, gender, energy needs, and if pregnant or lactating. However, when building total diets from the foundation diet, a 30 g serve daily can be included at all energy levels modelled.3

Australians' diets contain far fewer nuts than 30 g each day. While the 1995 National Nutrition survey results are dated, they found adults aged 19 years and over ate an average of 5 g of nuts per day, and children even less.4 A comparison5 of the 1995 children's figures with the 2007 Australian National Children's Nutrition and Physical Activity Survey6 concluded that consumption of all nuts had further fallen.

This continuing education quiz provides dietitians with updated knowledge on the health benefits of regular nut consumption and references for further reading. It aims to assist dietitians to understand how nuts can contribute positively to the nutrient profile of diets, with particular emphasis on clarifying their role in dietary advice addressing lifestyle-related disease.

  • 1
    Which of the following best reflects the findings of major observational studies on nut consumption and heart disease risk?
    • a. 
      Occasional nut consumption has no effect on heart disease risk.
    • b. 
      Regular consumption of nuts (about 30 g five times per week) can significantly reduce heart disease risk.
    • c. 
      The fat delivered by nuts increases heart disease risk, but only marginally.
    • d. 
      There is insufficient evidence that nuts can have any influence on cardiovascular disease.
  • 2
    Which of the following best reflects the results of meta-analyses on nut consumption and blood lipids?
    • a. 
      Around 30 g of nuts a day can reduce total and LDL blood cholesterol and triglycerides by 5–10%.
    • b. 
      Around two handfuls (∼60–70 g) of nuts a day can reduce total and LDL blood cholesterol and triglycerides by 7 and 10% respectively.
    • c. 
      Only a handful of almonds or walnuts can significantly lower blood cholesterol.
    • d. 
      Nuts have no positive effects on blood cholesterol levels.
  • 3
    Which of the following nutrients do nuts as a category contain?
    • a. 
      Monounsaturated and polyunsaturated fats, including the plant omega 3—alpha linolenic acid
    • b. 
      Antioxidant vitamin E
    • c. 
      Antioxidant minerals such as copper, manganese, selenium and zinc
    • d. 
      Fibre, plant sterols and the amino acid arginine
    • e. 
      Polyphenols such as resveratrol
    • f. 
      All of the above
  • 4
    Which of the following statements least reflect the current literature on nut consumption and diabetes?
    • a. 
      A study of over 84 000 women found that regular nut consumption can significantly reduce the risk of developing type-2 diabetes.
    • b. 
      Studies have shown that including nuts in meals containing carbohydrate can reduce postprandial blood glucose levels.
    • c. 
      Studies have shown nuts consumption can improve insulin resistance.
    • d. 
      Nuts should not be consumed as part of the diet for diabetes.
  • 5
    Which of the following statements about the role of nuts in weight management is correct?
    • a. 
      Studies show people who regularly eat a handful of nuts are more likely to have a lower body mass index (BMI).
    • b. 
      Nuts are high in fat which is readily absorbed and this explains why nuts are fattening.
    • c. 
      Eating nuts increases the appetite because they inhibit the satiety hormones in the gut.
    • d. 
      A recent study found that weight gain after 4 years was positively associated with nut consumption.
  • 6
    Which of the following nut allergy statements is correct?
    • a. 
      Women should not eat nuts during pregnancy and lactation as it will increase the risk of nut allergy in their child.
    • b. 
      Someone with an allergy to a specific nut can eat all the other nuts.
    • c. 
      Roasting nuts increases the allergenic potential of all nut types.
    • d. 
      They are all incorrect.

Answers

  1. Top of page
  2. Continuing education and the APD program
  3. Introduction
  4. Answers
  5. References
  • 1
    b
    • Evidence from a number of observational studies7–11 has found that nut consumption may be protective against cardiovascular disease. In general, consuming 30 g of nuts at least five times a week appears to reduce the risk of developing heart disease by around 30–50% compared with those who eat nuts less than once a week or never eat nuts.7–11Table 1 summarises major studies that support this finding.

  • 2
    b
    • A meta analysis of 25 nut and cholesterol-lowering intervention trials found that around two handfuls of nuts (∼67 g) on average each day significantly reduced total and LDL cholesterol by 5 and 7%, respectively (P < 0.001), without affecting HDL levels and reduced triglycerides by 10% (P < 0.05).12 This is further supported by two other meta-analyses specifically on almonds13 and walnuts14 which also support eating at least a handful a day to significantly lower total and LDL cholesterol by around 5% (P= 0.05). Studies of almonds show evidence of a dose response across an intake range of 34–100 g/day, suggesting that a greater benefit may be obtained from a higher intake of nuts.15,16 Significant cholesterol lowering can also be achieved by a variety of nuts including hazelnuts, macadamias, pecans and pistachio.17–28 Preliminary research is also finding that nuts affect LDL particle size with a reduction in small LDL cholesterol.28,29

  • 3
    f
    • As a natural, whole food nuts are nutrient dense, containing a number of nutrients and phytochemicals which can maintain heart health through different mechanisms.30 It is a case of the sum being greater than the individual parts. Monounsaturated and polyunsaturated fats help regulate cholesterol production.31 Alpha linolenic acid may play a role in maintaining heart health.32 Vitamin E, copper, manganese, selenium and zinc are antioxidant vitamin and minerals30 while polyphenols such as resveratrol have antioxidant and anti-inflammatory functions.33 Dietary fibre and plant sterols help lower cholesterol re-absorption in the gut,34,35 and the amino acid arginine improves endothelial function.36 Together, these may reduce the risk of atherosclerosis and heart disease.30

  • 4
    d
    • Nut consumption has positive effects on postprandial blood glucose and insulin resistance.37 Studies have found that including nuts can reduce the rise in blood glucose levels following a meal containing carbohydrate.38–40 Nut consumption may also improve insulin resistance.41 A study of ∼84 000 women found that those who ate ∼30 g serve of nuts, five or more times per week, had a 27% lower risk of developing diabetes compared with those who never or rarely ate nuts.42

  • 5
    a
    • Observational evidence shows that those who eat a small serve of nuts (∼30 g) 2–5 times a week do not weigh more than people who consume nuts less than once a week or never eat nuts.7–10,43,44 There is a trend towards frequent nut consumers having a lower BMI than non-consumers and that eating nuts regularly may reduce the risk of weight gain and developing obesity.44Table 2 summarises major studies that support this finding. A recent study published in the New England Journal of Medicine found that weight gain after 4 years was negatively associated with nut consumption.45

    • While nuts are high in fat, nut consumers excrete more fat. As a whole food with fibre, the digestion and absorption of the energy in nuts appears incomplete. Up to 15% of the energy in nuts is not absorbed.46–49 The fat and energy content of nuts, analysed in the laboratory and labelled on packs, may not reflect true fat and energy absorption by the body. Nut consumption can reduce the appetite as the fat in nuts can increase satiety hormones such as cholecystokinin in the digestive system.46,47,50,51 It appears that the action of shelling nuts also reduces energy intake as study participants ate less nuts when they had to shell their own.52

  • 6
    d
    • According to the Australasian Society of Clinical Immunology and Allergy, there is no evidence to suggest that women should make any dietary restrictions during pregnancy and lactation to reduce the risk of their children developing food allergies.53 Due to the risk of cross contact between different nut varieties in food manufacturing plants, it is a good idea to recommend nut allergic patients to avoid all nuts unless they are able to source the non-allergic nuts direct from the grower or a company that only sells that one nut variety. Processing does not change the allergenic potential of every nut variety but may dampen it in some nuts such as hazelnuts and pistachios.54–57

Table 1.  Effect of nut consumption on risk of coronary heart disease—epidemiological evidence
StudyNumber of subjects (sex)End pointsNut consumption frequencyRelative risk(a)P for trend
  • (a)

     Multivariate adjusted.

  • CHD, coronary heart disease; CVD, cardiovascular disease; MI, myocardial infarction.

  • Source: Nuts for Life—Eat Nuts Protect Your Health literature review summary 2011, http://www.nutsforlife.com.au

Nurses Health8Study86 016 (F)Total CHDAlmost never1.00 
≥5 serves/week0.65 (0.47–0.89)0.0009
Fatal CHDAlmost never1.00 
≥5 serves/week0.61 (0.35–1.05)0.007
Non-fatal MIAlmost never1.00 
≥5 serves/week0.68 (0.47–1.00)0.04
Californian Seventh-Day Adventist Health Study726 473 (M/F)Non-fatal MI<1 serve/week1.00 
≥5 serves/week0.49 (0.28–0.85)<0.005
Fatal CHD<1 serve/week1.00 
≥5 serves/week0.52 (0.36–0.76)<0.001
Physicians Health Study1021 454 (M)Sudden CHD death<1/month1.00 
≥2 serves/week0.53 (0.30–0.92)0.01
Fatal CHD<1/month1.00 
≥2 serves/week0.70 (0.50–0.98)0.06
Iowa Women's Health Study9 12-year follow-up34 111 (F)Fatal CHD<1 serve/month1.00 
≥2 serves/week0.81 (0.60–1.11)0.24
Iowa Women's Health Study11 15-year follow-up31 778 (F)Fatal CHD<1 serve/week1.03 (0.84–1.26) 
≥5 serves/week0.71 (0.55–0.91)0.02
Fatal CVD<1 serve/week1.00 (0.86–1.17) 
≥5 serves/week0.72 (0.60–0.88)0.0008
Table 2.  Effect of nut consumption on body weight
StudyNumber of subjects (sex)Nut consumption frequencyBMI (kg/m2)Trends
  1. Note: P-values for changes in BMI were not reported, and results are trends only (except for references 7 and 44).

  2. BMI, body mass index.

  3. Source: Nuts for Life—Eat Nuts Manage Your Weight literature review summary 2011, http://www.nutsforlife.com.au

Nurses' Health Study883 818 (F)Almost never24.8BMI decreased with increasing nut consumption
≥5 serves/week23.4
Iowa Women's Health Study934 111 (F)<1 serve/month27.1BMI decreased with increasing nut consumption
>5 serves/week26.2
California Seventh-Day Adventist Health Study731 208 (M/F)<1 serve/monthFigures not givenStatistically significant decrease in BMI with increasing nut consumption
≥5 serves/week
Physicians' Health Study1021 454 (M)Rarely/never24.9No association between nut consumption and BMI
≥2 serves/week24.7
The Sun Study438 865 (M/F)Rarely/never23.6No association between nut consumption and BMI
≥2 serves/week22.6
Nurses' Health Study II4451 188 (F)Rarely/never24.4Statistically significant lower risk of weight gain and obesity with nut consumption
≥2 serves/week23.8

References

  1. Top of page
  2. Continuing education and the APD program
  3. Introduction
  4. Answers
  5. References
  • 1
    Salas-Salvadó J, Casas-Agustench P, Salas-Huetos A. Cultural and historical aspects of Mediterranean nuts with emphasis on their attributed healthy and nutritional properties. Nutr Metab Cardiovasc Dis 2011; 1 (Suppl.): S16.
  • 2
    O'Neil CE, Keast DR, Fulgoni VL 3rd, Nicklas TA. Tree nut consumption improves nutrient intake and diet quality in US adults: an analysis of National Health and Nutrition Examination Survey (NHANES) 1999–2004. Asia Pac J Clin Nutr 2010; 19: 14250.
  • 3
    NHMRC. A new food guidance system for Australia—foundation and total diets. Revised draft report for Public Consultation By the Dietitians Association of Australia. Released May 2010. (Available from: http://www.nhmrc.gov.au/_files_nhmrc/file/guidelines/consult/consultations/draft_foundation_total_diets_public_consult.pdf, accessed May 2010).
  • 4
    Australian Bureau of Statistics. National nutrition survey: foods eaten, Australia 1995. 1999. (Available from: http://www.ausstats.abs.gov.au/ausstats/subscriber.nsf/0/CA25687100069892CA256888001CD460/$File/48040_1995.pdf, accessed 9 November 2011.
  • 5
    Rangan AM, Kwan JS, Louie JC, Flood VM, Gill TP. Changes in core food intake among Australian children between 1995 and 2007. Eur J Clin Nutr 2011; 65: 120110.
  • 6
    Australian Commonwealth Department of Health and Ageing, Australian Commonwealth Scientific and Research Organisation, University of South Australia. The 2007 National Children's Nutrition and Physical Activity Survey. Australian Social Science Data Archive. Canberra, Australia: The Australian National University, 2009.
  • 7
    Fraser GE, Sabaté J, Beeson WL, Strahan TM. A possible protective effect of nut consumption on risk of coronary heart disease. The Adventist Health Study. Arch Intern Med 1992; 152: 141624.
  • 8
    Hu FB, Stampfer MJ, Manson JE et al. Frequent nut consumption and risk of coronary heart disease in women: prospective cohort study. BMJ 1998; 317 (7169): 13415.
  • 9
    Ellsworth JL, Kushi LH, Folsom AR. 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: 3727.
  • 10
    Albert CM, Gaziano JM, Willett WC, Manson JE. Nut consumption and decreased risk of sudden cardiac death in the Physician's Health Study. Arch Intern Med 2002; 162: 13827.
  • 11
    Blomhoff R, Carlsen MH, Andersen LF, Jacobs DR Jr. Health benefits of nuts: potential role of antioxidants. Brit J Nutr 2007; 96 (Suppl. S2): S5260.
  • 12
    Sabaté J, Oda K, Ros E. Nut consumption and blood lipid levels: a pooled analysis of 25 intervention trials. Arch Intern Med 2010; 170: 8217.
  • 13
    Phung OJ, Makanji SS, White CM, Coleman CI. Almonds have a neutral effect on serum lipid profiles: a meta-analysis of randomized trials. J Am Diet Assoc 2009; 109: 86573. (Letter to the Editor J Am Diet Assoc 2009; 109 (9): 1521–2.)
  • 14
    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: 5663.
  • 15
    Jenkins DJ, Kendall CW, Marchie A et al. Dose response of almonds on coronary heart disease risk factors: blood lipids, oxidized low-density lipoproteins, lipoprotein(a), homocysteine, and pulmonary nitric oxide: a randomized, controlled, crossover trial. Circulation 2002; 106: 132732.
  • 16
    Sabate J, Haddad E, Tanzman JS, Jambazian P, Rajaram S. Serum lipid response to the graduated enrichment of a Step I diet with almonds: a randomized feeding trial. Am J Clin Nutr 2003; 77: 137984.
  • 17
    Garg ML, Blake RJ, Wills RB, Clayton EH. Macadamia nut consumption modulates favourably risk factors for coronary artery disease in hypercholesterolemic subjects. Lipids 2007; 42: 5837.
  • 18
    Garg ML, Blake RJ, Wills RB. Macadamia nut consumption lowers plasma total and LDL cholesterol levels in hypercholesterolemic men. J Nutr 2003; 133: 106063.
  • 19
    Curb JD, Wergowske G, Dobbs JC, Abbott RD, Huang B. Serum lipid effects of a high-monounsaturated fat diet based on macadamia nuts. Arch Intern Med 2000; 160: 11548.
  • 20
    Hudthagosol C, Haddad EH, McCArthy K, Wang P, Oda K, Sabaté J. Pecans acutely increase plasma postprandial antioxidant capacity and catechins and decrease LDL oxidation in humans. J Nutr 2011; 141: 5662.
  • 21
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  • 22
    Morgan WA, Clayshulte BJ. Pecans lower low-density lipoprotein cholesterol in people with normal lipid levels. J Am Diet Assoc 2000; 100 (3): 31218.
  • 23
    Sari I, Baltaci Y, Bagci C et al. Effect of pistachio diet on lipid parameters, endothelial function, inflammation, and oxidative status: a prospective study. Nutrition 2010; 26: 399404.
  • 24
    Kay CD, Gebauer SK, West SG, Kris-Etherton PM. Pistachios increase serum antioxidants and lower serum oxidized-LDL in hypercholesterolemic adults. J Nutr 2010; 140: 10938.
  • 25
    Sheridan MJ, Cooper JN, Erario M, Cheifetz CE. Pistachio nut consumption and serum lipid levels. J Am Coll Nutr 2007; 26: 1418.
  • 26
    Mercanligil SM, Arslan P, Alasalvar C et al. Effects of hazelnut-enriched diet on plasma cholesterol and lipoprotein profiles in hypercholesterolemic adult men. Eur J Clin Nutr 2007; 61: 21220.
  • 27
    Tey SL, Brown RC, Chisholm AW, Delahunty CM, Gray AR, Williams SM. Effects of different forms of hazelnuts on blood lipids and α-tocopherol concentrations in mildly hypercholesterolemic individuals. Eur J Clin Nutr 2011; 65: 11724.
  • 28
    Yücesan FB, Orem A, Kural BV, Orem C, Turan I. Hazelnut consumption decreases the susceptibility of LDL to oxidation, plasma oxidized LDL level and increases the ratio of large/small LDL in normolipidemic healthy subjects. Anadolu Kardiyol Derg 2010; 10: 2835.
  • 29
    Almario RU, Vonghavaravat V, Wong R, Kasim-Karakas SE. Effects of walnut consumption on plasma fatty acids and lipoproteins in combined hyperlipidemia. Am J Clin Nutr 2001; 74: 729.
  • 30
    Ros E. Nuts and novel biomarkers of cardiovascular disease. Am J Clin Nutr 2009; 89 (5): 1649S56S.
  • 31
    Mozaffarian D. Effects of dietary fats versus carbohydrates on coronary heart disease: a review of the evidence. Curr Atheroscler Rep 2005; 7 (6): 43545.
  • 32
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  • 33
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  • 34
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  • 35
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  • 36
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  • 37
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  • 38
    Jenkins DJ, Kendall CW, Josse AR et al. Almonds decrease postprandial glycemia, insulinemia, and oxidative damage in healthy individuals. J Nutr 2006; 136: 298792.
  • 39
    Josse AR, Kendall CW, Augustin LS, Ellis PR, Jenkins DJ. Almonds and postprandial glycemia—a dose-response study. Metabolism 2007; 56: 4004.
  • 40
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  • 41
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  • 42
    Jiang R, Manson JE, Stampfer MJ, Liu S, Willett WC, Hu FB. Nut and peanut butter consumption and risk of type 2 diabetes in women. JAMA 2002; 288: 255460.
  • 43
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  • 44
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  • 45
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  • 46
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  • 47
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  • 48
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  • 49
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  • 50
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  • 51
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  • 52
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  • 53
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  • 54
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  • 55
    Hansen KS, Ballmer-Weber BK, Lüttkopf D et al. Roasted hazelnuts—allergenic activity evaluated by double-blind, placebo-controlled food challenge. Allergy 2003; 58: 1328.
  • 56
    Roux KH, Teuber SS, Robotham JM, Sathe SK. Detection and stability of the major almond allergen in foods. J Agric Food Chem 2001; 49 (5): 21316.
  • 57
    Noorbakhsh R, Mortazavi SA, Sankian M et al. Influence of processing on the allergenic properties of pistachio nut assessed in vitro. J Agric Food Chem 2010; 58 (18): 102315.