Consumption of Nuts and Similar Dried Foods in Portugal and Level of Knowledge about their Chemical Composition and Health Effects

Document Type : Research Article


1 CERNAS Research Centre, Polytechnic Institute of Viseu, 3504-510 Viseu, Portugal

2 Department of Food Industry, Agrarian School of Viseu, 3500-606 Viseu, Portugal

3 Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal


Nuts are consumed worldwide and have valuable nutritional compositions. However, few studies exist about the consumers’ knowledge regarding nuts and similar dried fruits. This study aimed to investigate the knowledge on nuts composition (KNC) and health effects (KNHE) associated with nuts consumption and evaluate eating habits and preferences. A questionnaire survey was applied by direct interview to 300 Portuguese citizens, recruited by convenience. Anthropometric properties, behavioural and health aspects, knowledge about nuts composition and health effects, and consumption habits and preferences were evaluated and statistically analysed. Globally, the participants were not well informed on the chemical composition of nuts and about their effects on human health. Regarding age, the middle-aged adults showed a little higher level of KNC. However, no statistical differences were observed for KNC and KNHE across groups of Body Mass Index, physical exercise practice or balanced diet. Concerning eating habits and preferences, most participants (84%) like nuts, and usually consume them (58%). Among different nuts, the most consumed ones were peanuts and walnuts, followed by almonds and hazelnuts. A vast majority of participants (86%) preferred to eat the nuts in their simple form and consume them between meals. In conclusion, improvement of communication on nuts benefits to human health might be a way to increase their consumption. Our data can also help the nut industries to formulate a better strategy.


Alasalvar C, Salvadó JS, Ros E (2020) Bioactives and health benefits of nuts and dried fruits. Food Chemistry. 314, 126192. 10.1016/j.foodchem.2020.126192
Apostu M, Predescu C (2015) The Benefits of Implementing a Program for Information and Monitoring the Teenagers with Overweight Risk. Procedia - Social and Behavioral Sciences, 191, 2272–2274.
Bai W, Liu W, Guo J, Jia Q, Wang X, Li Z (2018) Investigation on consumer behavior of consumers in nut market. Marketing Week. 12, 94–95.
Beccia AL, Baek J, Jesdale WM, Austin SB, Forrester S, Curtin C, Lapane KL (2019) Risk of disordered eating at the intersection of gender and racial/ethnic identity among U.S. high school students. Eating Behaviors. 34, 101299.
Bitok E, Sabaté J (2018) Nuts and Cardiovascular Disease. Progress in Cardiovascular Diseases. 61(1), 33–37. 1016/j.pcad.2018.05.003
Borooah VK (2004) Gender bias among children in India in their diet and immunisation against disease. Social Science & Medicine. 58(9), 1719–1731. 9536(03)00342-3
Burlingame B, Dernini S (2010) Sustainable Diets and Biodiversity: Directions and Solutions for Policy, Research and Action. In Proceedings of the International Scientific Symposium. Presented at the Biodiversity and Sustainable Diets United Against Hunger, Rome, Italy: FAO - Food and Agriculture Organization of the United Nations.
Bvenura C, Sivakumar D (2017) The role of wild fruits and vegetables in delivering a balanced and healthy diet. Food Research International. 99, 15–30.
Campbell HM, Khan N, Cone C, Raisch DW (2011) Relationship between diet, exercise habits, and health status among patients with diabetes. Research in Social and Administrative Pharmacy. 7(2), 151–161.
Catalán L, AlvarezOrtí M, Pardo Giménez A, Gómez R, Rabadán A, Pardo JE (2017) Pistachio oil: A review on its chemical composition, extraction systems, and uses. European Journal of Lipid Science and Technology. 119(5), 1600126. /10.1002 /ejlt.201600126
Chatrabnous N, Yazdani N, Vahdati K (2018) Determination of nutritional value and oxidative stability of fresh walnut. Journal of Nuts. 9(1), 11-20.
Davis FB (1964) Educational Measurements Their Interpretation. USA: Wadsworth Pub. Co. Accessed 25 January 2015
DGDR (2001) Produtos Tradicionais Portugueses. Lisbon, Portugal: Direção Geral de Agricultura e Desenvolvimento Rural.
 Dongen EJI, Haveman-Nies A, Doets EL, Dorhout BG, de Groot LCPGM (2020) Effectiveness of a Diet and Resistance Exercise Intervention on Muscle Health in Older Adults: ProMuscle in Practice. Journal of the American Medical Directors Association.
Duduzile Buthelezi NM, Tesfay SZ., Ncama K, Magwaza LS (2019) Destructive and non-destructive techniques used for quality evaluation of nuts: A review. Scientia Horticulturae. 247, 138–146. https://doi. org/10.1016/j.scienta.2018.12.008
Eslami O, Shidfar F, Dehnad A (2019) Inverse association of long-term nut consumption with weight gain and risk of overweight/obesity: a systematic review. Nutrition Research. 68, 1–8.
Fitzpatrick KM, Shi X, Willis D, Niemeier J (2018) Obesity and place: Chronic disease in the 500 largest U.S. cities. Obesity Research & Clinical Practice. 12(5), 421–425.
Gaio V, Antunes L, Namorado S, Barreto M, Gil A, Kyslaya I, Rodrigues AP, Santos A, Bøhler L, Castilho E, Vargas P, Carmo I, Nunes B, Dias CM (2018) Prevalence of overweight and obesity in Portugal: Results from the First Portuguese Health Examination Survey (INSEF 2015). Obesity Research & Clinical Practice. 12(1), 40–50.
Ghazzawi HA, Akash KAIM (2019) Consumption practices, preferences and barriers of nuts intake amongst university of Jordan students. Clinical Nutrition Experimental, 24, 45–53. /j.yclnex.2019.01.001
Gibbs HD, Ellerbeck EF, Gajewski B, Zhang C, Sullivan DK (2018) The Nutrition Literacy Assessment Instrument is a Valid and Reliable Measure of Nutrition Literacy in Adults with Chronic Disease. Journal of Nutrition Education and Behavior. 50(3), 247–257.
Gomez-Pinilla F (2008) The influences of diet and exercise on mental health through hormesis. Ageing Research Reviews. 7(1), 49–62.
Guiné Rde PF (2019) Study of Consumer Acceptance by Means of Questionnaire Survey Towards Newly Developed Yogurts with Functional Ingredients. Current Nutrition & Food Science. 15(3), 243–256.
Hair JFH, Black WC, Babin BJ, Anderson RE (2009) Multivariate Data Analysis (7 edition.). s.l.: Prentice Hall.
Halloran DR, Marshall NE, Kunovich RM, Caughey AB (2012) Obesity trends and perinatal outcomes in black and white teenagers. American Journal of Obstetrics and Gynecology. 207(6), 492.e1-492.e7.
Hazrati S, Govahi M, Ebadi MT, Habibzadeh F (2020) Comparison and evaluation of oil content, composition and antioxidant properties of Pistacia atlantica and Pistacia khinjuk grown as wild. International Journal of Horticultural Science and Technology. 7(2), 165-74
Hong L, Yao L, Xie P, Li W (2020) An empirical study on consumer purchase intention for nuts and influencing factors—Survey based on consumers from Zhejiang. Food Control. 117, 107343. /10.1016/j. foodcont.2020.107343
 Ibarrola-Jurado N, Bulló M, Guasch-Ferré M, Ros E, Martínez-González MA, Corella D, Fiol M, Wärnberg J, Estruch R, Román P, Arós F, Vinyoles E, Serra-Majem L, Pintó X, Covas MI, Basora J, Salas-Salvadó J (2013) Cross-sectional assessment of nut consumption and obesity, metabolic syndrome and other cardiometabolic risk factors: the PREDIMED study. PloS One. 8(2), e57367. /10.1371 /journal.pone.0057367
Jahanbani R, Ghaffari SM, Salami M, Vahdati K, Sepehri H,  Namazi Sarvestani N, Sheibani N, Moosavi-Movahedi AA (2016) Antioxidant and anticancer activities of walnut (Juglans regia L.) protein hydrolysates using different proteases. Plant Foods and Human Nutrition. 71: 402-409.
Jahanbani R, Ghaffari SM, Vahdati K, Salami M, Khalesi MR, Sheibani N, Moosavi-Movahedi AA (2018) Kinetics study of protein hydrolysis and inhibition of angiotensin converting enzyme by peptides hydrolysate extracted from walnut. International Journal of Peptide Research and Therapeutics. 24(1):77-85.
Kodad O., Estopañán G., Juan T., Company RSI, Sindic M (2016) Genotype and year variability of the chemical composition of walnut oil of Moroccan seedlings from the high Atlas Mountains. Grasas y Aceites. 67(1), 116. /10. 3989/gya.0256151
Lee J, Callaghan T, Ory M, Zhao H, Bolin J (2020) Difference in the risk of depressive symptoms associated with physical activity in persons with diabetes: Across age, gender, and race/ethnicity. Journal of Affective Disorders.  269, 108–116. /10.1016/j.jad.2020.03.035
Li Q, Cai L, Cui W, Wang G, He J, Golden AR  (2018) Economic burden of obesity and four obesity-related chronic diseases in rural Yunnan Province, China. Public Health. 164, 91–98.
Liu X, Zhang D, Liu Y, Sun X, Han C, Wang B, Ren Y, Zhou J , Zhao Y, Shi Y, Hu D, Zhang M (2017) Dose-Response Association Between Physical Activity and Incident Hypertension: A Systematic Review and Meta-Analysis of Cohort Studies. Hypertension (Dallas, Tex.: 1979). 69(5), 813–820. https: //doi. org/10.1161/HYPERTENSIONAHA.116.08994
Looze M, Elgar FJ, Currie C, Kolip P, Stevens GWJM (2019) Gender Inequality and Sex Differences in Physical Fighting, Physical Activity, and Injury Among Adolescents Across 36 Countries. Journal of Adolescent Health. 64(5), 657–663.
Malan H, Watson TD, Slusser W, Glik D, Rowat AC, Prelip M (2020) Challenges, Opportunities, and Motivators for Developing and Applying Food Literacy in a University Setting: A Qualitative Study. Journal of the Academy of Nutrition and Dietetics. 120(1), 33–44.
Maroco J, Garcia-Marques T (2006) Qual a fiabilidade do alfa de Cronbach? Questões antigas e soluções modernas? http:// Accessed 25 January 2015
May J (2018) Keystones affecting sub-Saharan Africa’s prospects for achieving food security through balanced diets. Food Research International. 104, 4–13.
Palumbo R, Adinolfi P, Annarumma C, Catinello G, Tonelli M, Troiano E, Vezzosi S, Manna R  (2019) Unravelling the food literacy puzzle: Evidence from Italy. Food Policy. 83, 104–115. foodpol. 2018. 12.004
Paola CE, Paola D, Anna DCG, Antonietta A, Fernando PM (2009) An Excessive Attention for Food Calories is a Risk Factor of Eating Disorders in Teenagers: Studies Issues “Make Peace with Food.” Journal of Nutrition Education and Behavior, 41(4, Supplement), S17. /10. 1016/j.jneb.2009.03.148
Pharr JR, Coughenour CA, Bungum TJ (2018) An assessment of the relationship of physical activity, obesity, and chronic diseases/conditions between active/obese and sedentary/ normal weight American women in a national sample. Public Health. 156, 117–123. https: //doi. org/10. 1016/j.puhe.2017.12.013
Pinstrup-Andersen P (2007) Agricultural research and policy for better health and nutrition in developing countries: a food systems approach. Agricultural Economics. 37(s1), 187–198. 1574- 0862.2007.00244.x
Powell HS, Greenberg DL (2019) Screening for unhealthy diet and exercise habits: The electronic health record and a healthier population. Preventive Medicine Reports. 14, 100816. /10. 1016/j. pmedr.2019.01.020
Rabadán A, Álvarez-Ortí M, Pardo JE (2019) A comparison of the effect of genotype and weather conditions on the nutritional composition of most important commercial nuts. Scientia Horticulturae. 244, 218–224.
Robbins KS, Shin EC, Shewfelt RL, Eitenmiller RR, Pegg RB (2011) Update on the healthful lipid constituents of commercially important tree nuts. Journal of Agricultural and Food Chemistry. 59(22), 12083–12092.
Robert MC (2019) Food Allergens: Seafood, Tree Nuts, Peanuts. In L. Melton, F. Shahidi, & P. Varelis (Eds.), Encyclopedia of Food Chemistry  Oxford: Academic Press. pp. 640–647.
Roncero JM, Álvarez-Ortí M, Pardo-Giménez A, Gómez R, Rabadán A, Pardo JE (2016) Virgin almond oil: Extraction methods and composition. Grasas y Aceites. 67(3), e143.
Roozban MR, Mohamadi N and Vahdati K (2005) Fat content and fatty acid composition of four Iranian pistachio varieties grown in Iran. Acta Horticulturae. 726, 573-577.
Ros E (2016) Nuts: Health Effects. In B. Caballero PM Finglas, Toldrá F (Eds.), Encyclopedia of Food and Health.  Oxford: Academic Press. https://doi. org/10.1016/B978 -0-12-384947-2.00496-7. pp. 111–118.
Ros Emilio (2017) Eat Nuts, Live Longer. Journal of the American College of Cardiology. 70(20), 2533–2535.
Rosselli M, Ermini E, Tosi B, Boddi M, Stefani L, Toncelli L, Modesti PA (2020) Gender differences in barriers to physical activity among adolescents. Nutrition, Metabolism and Cardiovascular Diseases. https://doi. org/10.1016/j.numecd.2020.05.005
Sarikhani S, Vahdati K, Ligterink W (2021) Biochemical properties of superior persian walnut genotypes originated from southwest of Iran. International Journal of Horticultural Science and Technology. 8(1), 13-24.
Schoenaker DAJM, Mishra GD, Callaway LK, Soedamah-Muthu SS (2016) The Role of Energy, Nutrients, Foods, and Dietary Patterns in the Development of Gestational Diabetes Mellitus: A Systematic Review of Observational Studies. Diabetes Care. 39(1), 16–23.
Segura R, Javierre C, Lizarraga MA, Ros E (2006) Other relevant components of nuts: phytosterols, folate and minerals. British Journal of Nutrition. 96(S2), S36–S44.
Soon JM (2018) ‘No nuts please’: Food allergen management in takeaways. Food Control. 91, 349–356. /10.1016/j. foodcont.2018.04.024
Souza RGM, Schincaglia RM, Pimentel GD, Mota JF (2017) Nuts and Human Health Outcomes: A Systematic Review. Nutrients. 9(12).
Stringhini S, Carmeli C, Jokela M, Avendaño M, Muennig P, Guida F, Ricceri F, d'Errico A, Barros H, Bochud M, Chadeu-Hyam M, Clavel-Chapelon F, Costa G, Delpierre C, Fraga S, Goldberg M, Giles GG, Krogh V, Kelly-Irving M, Layte R, Lasserre AM, Marmot MG, Preisig M, Shipley MJ, Vollenweider P, Zins M, kawachi I, Steptoe A, Mackenbach J, Vineis P, Kivimäki M (2017) Socioeconomic status and the 25 × 25 risk factors as determinants of premature mortality: a multicohort study and meta-analysis of 1·7 million men and women. The Lancet. 389(10075), 1229–1237. https://doi. org/10. 1016/ S0140 -6736(16)32380-7
Sze-Tao KWC, Sathe SK (2000) Walnuts (Juglans regia L): proximate composition, protein solubility, protein amino acid composition and protein in vitro digestibility. Journal of the Science of Food and Agriculture. 80(9), 1393–1401.<1393::AID-JSFA653>3.0.CO;2-F
Tan SY, Dhillon J, Mattes RD (2014) A review of the effects of nuts on appetite, food intake, metabolism, and body weight. The American Journal of Clinical Nutrition. 100(suppl_1), 412S-422S. https:// 10.3945/ajcn.113.071456
Thomas H, Azevedo Perry E, Slack J, Samra HR, Manowiec E, Petermann L, Manafò E, Kirkpatrick SI (2019) Complexities in Conceptualizing and Measuring Food Literacy. Journal of the Academy of Nutrition and Dietetics. 119(4), 563–573.
Travassos GF, Antônio da Cunha D, Coelho AB (2020) The Environmental Impact Of Brazilian Adults’ Diet. Journal of Cleaner Production. 122622.
Tuomela J, Kaprio J, Sipilä PN, Silventoinen K, Wang X, Ollikainen M, Piirtola M (2019) Accuracy of self-reported anthropometric measures — Findings from the Finnish Twin Study. Obesity Research & Clinical Practice. 13(6), 522–528. /10.1016/ j.orcp.2019.10.006
Vale PL (2019) Frutos secos | Celeiro. Accessed 2 March 2019
Vahdati K, Sarikhani Khorami S, Arab MM (2018) Walnut: a potential multipurpose nut crop for reclaiming deteriorated lands and environment. Acta Horticulturae 1190, 95-100.
Vargova V, Singh RB, Fedacko J, Pella D, Pella D, Wilczynska A, Mojto V (2019) Chapter 20 - Effects of Nuts Consumption on Cardiometabolic Diseases and Cancer. In R. B. Singh, R. R. Watson, & T. Takahashi (Eds.), The Role of Functional Food Security in Global Health  Academic Press. pp. 347–364.
WHO (2010) Global recommendations on physical activity for health. World Health Organization.
WHO (2019, December 29) Body mass index - BMI. Accessed 29 December 2019
Wills W, Backett-Milburn K, Gregory S, Lawton J (2006) Young teenagers’ perceptions of their own and others’ bodies: A qualitative study of obese, overweight and ‘normal’ weight young people in Scotland. Social Science & Medicine. 62(2), 396–406. /10.1016/j.socscimed.2005.06.014.
Witte RS, Witte JS (2017) Statistics (11th ed.). Wiley Publishing, New Jersey, United States of America, 496 pp.
Yada S, Lapsley K, Huang G (2011) A review of composition studies of cultivated almonds: Macronutrients and micronutrients. Journal of Food Composition and Analysis. 24(4), 469–480. https://doi. org/10.1016/j. jfca. 2011.01.007