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Nutrient intakes of Greek forest workers and researchers do not meet all Reference Dietary Intakes
Nutrition Research 27 (2007) 321 – 326 www.elsevier.com/locate/nutres
Nutrient intakes of Greek forest workers and researchers do not meet all Reference Dietary Intakes Christos Gallis4, Panayota Panagopoulou Forest Research Institute, Vasilika, 57 006 Thessaloniki, Greece Received 9 February 2007; revised 6 April 2007; accepted 13 April 2007
Abstract In heavy work such as forest work, nutrient demand and energy expenditure are high. Therefore, adequate nutrient and energy intake of forest workers is of paramount importance. The objective of this cross-sectional study was to investigate the daily nutrient intake of forest workers and to determine if it meets the Reference Dietary Intakes (RDIs). A total of 21 forest workers and 21 researchers, who served as a control group, were enrolled. Nutrient intake was assessed on the basis of a 24-hour diet recall questionnaire, repeated for 3 consecutive weekdays. Daily nutrient intake was calculated using the NutriBase IV Clinical Edition Software package. Energy, protein, total lipids, saturated fatty acids, cholesterol, phosphorus, and sodium intake of forest workers was higher than the RDIs and significantly higher ( P b .05) than that of researchers. Most forest workers (90.47%) and researchers (95.32%) consumed less carbohydrate than the RDIs. Dietary fiber, riboflavin, vitamin E, vitamin D, and minerals intake was less than the RDI in both groups. Especially low was the daily intake of vitamin D and iodine in forest workers in comparison to RDIs and researchers. The results indicate that fundamental changes in daily nutrient intake for both groups are recommended. D 2007 Elsevier Inc. All rights reserved. Keywords:
Human; Nutrient intake; Greek; Forest workers; Researchers
1. Introduction Physically heavy work is still widespread among forest operators working in harvesting timber. To keep forestry workers in a good state of health and productivity, daily nutrition quality and quantity should be adequate and balanced [1]. Nutrition plays a major role in human health [2-6]. In forest work, which is heavy work, the nutrient demand and energy expenditure are high. Therefore, adequate nutrient and energy intake of forest workers is of paramount importance. If daily energy expenditure is higher than the energy intake, subsequently the energy balance becomes negative. Few quantitative studies, which are summarized in 4 Corresponding author. Tel.: +30 231 0 461 172x216; fax: +30 231 0 461 341. E-mail address: [email protected] (C. Gallis). 0271-5317/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.nutres.2007.04.005
an International Labor Office publication in 1989 [7], have assessed the daily energy intake of forest workers in different countries. According to the previously mentioned International Labor Office publication, in Finland (1960), an average daily energy intake of 4763 kcal per 24 hours was reported; in Canada (1973), daily meals provided 5500 kcal; and in the Netherlands (1972), a daily energy intake of 4260 kcal was calculated. In a study on German forest workers [8], it was reported that daily meals provided 4530 kcal on average. In Chile, during a case study of 57 forestry workers, a mean daily energy intake of 3519 kcal and an energy expenditure of 3541 kcal were recorded [9]. However, all this information has been collected mostly in Nordic countries, whereas such information for Mediterranean countries is sparse. Despite the known role of nutrition in human health worldwide, there are no current studies describing the daily
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Table 1 Anthropometric, demographic, and body composition characteristics of forest workers and researchers Variable Age (y) Weight (kg) Height (m) BMI (kg/m2) BMR (kcal)
Forest workers 42.3 F 11.1 78.2 F 18 1.80 F 0.1 24.13 F 3.00 1759 F 210
Researchers 51 F 6.6 89.9 F 11 1.74 F 0.05 29.69 F 3.4 1681.4 F 124
Values are means F standard deviation (n = 21).
nutrient intake of forest workers and researchers. This is also the case in Greece, where nutrient intake analysis of forest workers and researchers has not received any attention. In fact, forest work in Greece is characterized by heavy manual tasks on steep mountain slopes requiring high physical effort. Thus, it is essential to determine if workers have adequate daily nutrient intake meeting the Reference Dietary Intakes (RDIs). The objective of this study was to investigate the daily nutrient intake, by using a 24-hour recall assessment method, of forest workers and researchers and to determine if it meets the RDIs. 2. Methods and materials 2.1. Study population A sample of 21 male forest workers from the village of Sideronero in the Drama region of Northern Greece and 21 researchers from the National Agricultural Research Foundation’s Research Institutes of Thessaloniki (serving as a control group), matched for age and sex, was investigated (Table 1). They were randomly selected from a list of 53 male researchers and 120 forest workers.
The forest workers were self-employed in timber harvesting, a rather energy-intensive job in steep mountain forests characterized by vigorous physical activity [10]. The level of their education was of that of elementary school. In contrast, the researchers’ group was characterized by sedentary physical activities, holding a PhD degree, mostly spending daily working time in office, and computer work [10]. Only male forest workers and researchers participated because no female work professionally in timber-harvesting operations in Greece. The study was carried out in the summer of 2004. Each subject was interviewed individually in a private one-on-one interview. All the interviews were performed by the first author. Approval to implement the study protocol was obtained from the Forest Research Institute Scientific Committee and for human subject use from the local Ethics Committee of Drama Regional Authority. 2.2. Anthropometry and body composition Body weight, height, and body mass index (BMI; kg/m2) were measured. To estimate basic energy needs of the participants, the basal metabolic rate (BMR) was calculated using bioelectrical impedance analysis (MALTRON BF900) (Table 1) according to the European guidelines for bioelectrical impedance analysis [11]. 2.3. Nutrient intake calculation procedure Nutrient intake was assessed on the basis of a 24-hour diet recall questionnaire [12-18], repeated for 3 consecutive weekdays [7,13,14], using a semistructured diary. Individual interviews of each participant were conducted to record the nutrient intake of the previous day. The interviews were
Table 2 Energy and macronutrient daily intakes and percentage of RDI of the forest workers and researchers Nutrients Energy intake (kcal) Protein (g) Calories from protein % calories from protein Carbohydrate (g) Calories from carbohydrates % calories from carbohydrates Total lipid (fat) (g) Calories from fat % calories from fat Fatty acids, saturated (g) Fatty acids, monounsaturated (g) Fatty acids, polyunsaturated (g) Fatty acids, total trans (g) Omega-3 (g) Omega-6 (g) Cholesterol (mg) Fiber, total dietary (g) Water (g) Alcohol (g)
Mean F SD Forest workers 2705.97 F 1089.714 101.37 F 39.024 400.95 F 152.864 15.26 F 3.31 223.06 F 109.44 881.49 F 429.01 31.59 F 6.404 128.08 F 57.564 139.44 F 509.114 42.40 F 7.23 35.53 F 20.45 56.46 F 23.584 10.57 F 4.054 0.35 F 0.85 1.68 F 1.014 6.99 F 2.634 330.98 F 145.034 19.95 F 19.32 2238.72 F 1999.194 41.11 F 35.864
Percentage of RDI Researchers 1857.98 F 542.75 70.01 F 17.02 276.56 F 66.93 15.38 F 3.21 178.59 F 73.59 703.82 F 284.81 37.11 F 9.14 93.15 F 33.44 827.89 F 297.74 44.69 F 7.64 8.60 F 8.76 39.38 F 16.79 8.64 F 2.74 0.33 F 1.02 0.74 F 0.46 5.47 F 2.47 237.19 F 94.36 15.43 F 10.93 1244.5 F 691.66 7.18 F 6.74
Forest workers 113.88 F 0.504 112.85 F 0.414
Researchers 83.71 F 0.30 83.47 F 0.24
61.95 F 0.31
54.00 F 0.25
192.70 F 0.904
51.10 F 0.63
160.97 F 0.98
138.83 F 0.51
139.16 F 0.634 79.99 F 0.70 73.34 F 0.634
106.74 F 0.47 70.95 F 0.54 43.02 F 0.25
4 Denotes statistically significant difference from researchers at P V .05 as determined by unpaired t test (n = 21).
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Table 3 Vitamin daily intakes and percentage of RDI of the forest workers and researchers Vitamin Vitamin A (IU) Thiamine (mg) Riboflavin (mg) Niacin (mg) Pantothenic acid (mg) Vitamin B6 (mg) Folate (lg) Folic acid (lg) Vitamin B12 (lg) Vitamin C (mg) Vitamin D (IU) Vitamin E (IU)
Mean F SD Forest workers 4700.89 F 4614.89 0.90 F 0.39 1,39 F 0.54 21.81 F 10.074 4.20 F 4.16 2.07 F 1.304 247.66 F 231.65 2 8.21 F 42.31 9.07 F 5.144 126.64 F 130.22 47.10 F 62.63 13.91 F 6.38
Percentage of RDI Researchers 6479.99 F 10953.06 0.75 F 0.33 1.30 F 0.43 11.99 F 4.34 2.81 F 1.29 1.27 F 0.39 201.60 F 89.33 34.58 F 39.50 3.26 F 2.29 103.50 F 65.58 28.96 F 26.36 12.97 F 8.72
Forest workers 94.01 F 0.92 64.31 F 0.27 86.61 F 0.35 123.69 F 0.594
Researchers 129.59 F 2.19 58.51 F 0.29 86.43 F 0.31 72.50 F 0.26
103.29 F 0.654 123.83 F 1.15
63.49 F 0.19 100.83 F 0.44
453.53 F 211.09 F 23.56 F 93.39 F
163.03 172.50 14.48 87.09
2.574 2.17 0.31 0.42
F F F F
1.14 1.09 1.13 0.58
4 Denotes statistically significant difference from researchers at P V .05 as determined by unpaired t test (n = 21).
structured to assist the participants in recalling all foods and beverages consumed throughout the day. Participants who received vitamin and mineral supplements were excluded. In the diaries, days were segmented into 6 eating occasions, namely breakfast, between breakfast and lunch, lunch, between lunch and dinner, dinner, after dinner, and any snack eaten throughout the day. Information on the type, including brand names, and amount of food consumed was collected. After completion, food models were used to quantify portions [19,20]. For each subject, separately, the nutrient intake was calculated using the NutriBase IV Clinical Edition Software package [21], which also contains the United States Department of Agriculture Nutrient Database for Standard References. Nutribase IV software was used because no local software exists. The software also calculated the calories derived from protein, carbohydrates, and total lipids as the percentage of the daily RDI for each subject. The percentage contribution of dietary fibers and alcohol to total energy intake was calculated by application of the general Atwater energy conversion factors 2-7, respectively [22].
2.4. Statistical methods Descriptive statistics are expressed as mean values and standard deviations (mean F SD) [23]. Comparison of mean values between forest workers and researchers was conducted using the unpaired t test to define differences between the 2 groups. All analyses were performed using the statistical package SPSS [23]. Statistical significance was set at P V .05.
3. Results and discussion This study, which treats the nutrient intake and energy expenditure in a demanding energy occupation such as forest work, revealed significant nutrient deviations from the RDI recommendations. Forest workers had unexpectedly lower daily intake than the RDIs in carbohydrates, fibers, iodine, water, and part of vitamins such as A, D, E, thiamine, and riboflavin (Tables 2-4). They had higher than recommended daily intake of protein, total lipids, saturated fatty acids, cholesterol, niacin, vitamin B6, total folate, vitamin B12, and
Table 4 Mineral daily intakes and percentage of RDI for forest workers and researchers Nutrient Calcium (mg) Chromium (lg) Copper (mg) Fluoride (mg) Iodine (lg) Iron (mg) Magnesium (mg) Manganese (mg) Molybdenum (lg) Phosphorus (mg) Potassium (mg) Selenium (lg) Sodium (mg) Zinc (mg)
Mean F SD Forest workers 705.71 F 472.40 10.62 F 7.814 0.97 F 0.59 0.11 F 0.104 14.50 F 16.574 9.01 F 5.56 248.38 F 215.15 2.40 F 2.534 0.21 F 0.97 1076.61 F 495.104 2954.76 F 2447.10 61.86 F 27.234 3738.22 F 4228.88 7.24 F 3.92
Percentage of RDIs Researchers 695.45 F 235.76 5.21 F 3.58 0.76 F 0.41 0.04 F 0.02 6.13 F 5.85 7.97 F 4.08 166.63 F 61.29 1.33 F 0.72 0.29 F 1.01 817.81 F 226.25 2272.03 F 1225.35 43.98 F 15.94 2401.10 F 693.04 6.63 F 2.76
4 Denotes statistically significant difference ( P b .05) from the researchers (n = 21).
Forest workers 88.22 F 0.59
Researchers 86.93 F 0.29
9.66 F 0.114 90.10 F 0.55 70.96 F 0.60
4.08 F 0.03 79.701 F 0.40 47.61 F 0.17
134.59 F 0.614
102.22 F 0.28
88.38 F 0.384 163.96 F 1.75 48.23 F 0.26
62.83 F 0.22 109.52 F 0.35 44.22 F 0.18
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vitamin C (Tables 2 and 3). The total lipids intake was indeed high, but the quality of lipids was of high value because it resulted from the content in polyunsaturated fatty acid (PUFA) (Table 2). It is notable that the daily intake of sodium highly exceeded the RDI (Table 4). Regarding the total energy in calories, it was found that the forest workers had a higher intake than the RDI (Table 2). In the control group consisting of researchers, lower energy, protein, carbohydrate, fiber, and water intake than the RDIs as well as lower than those of forest workers were found (Table 2). Differences in BMI and BMR between the 2 groups were observed, with forest workers having lower BMI and higher BMR than researchers. Basal metabolic rate of forest workers was calculated at 1759 kcal/d. This represents the amount of energy expended while at rest in a neutrally temperate environment in the postabsorptive state [24]. In this study, the energy intake of forest workers was calculated to be 2705.97 kcal/d. This intake meets and exceeds the requirements for light work but not the needs for very active, heavy work such as that of forest workers performed in our study. Moreover, it is lower than that calculated by Apud et al [7] for Chilean forest workers, which was 3432 kcal during weekdays. According to the Food and Agriculture Organization [10], for very active forest workers, the energy expenditure per hour of work is 240 kcal. The average working hours of forest workers in our study were about 9 hours per day; thus, the energy expenditure during work is estimated at 2160 kcal. It means that the total energy intake needed to cover the BMR requirements and the energy for work is estimated at 3919 kcal. Thus, the deficiency in energy is estimated at 1193 kcal. On the other hand, the group of researchers in our study does light office work and their energy requirements are not as high as for forest workers. The BMR was calculated at 1681.4 kcal. Their energy intake was calculated at 1857.98 kcal, which is below the daily recommended intake for light work [10]. Forest workers meet the RDIs for protein intake, with 101.37 g/d, which is in agreement with that reported for Chilean forest workers’ intake of 109.7 g/d [7], whereas researchers had a lower protein intake (70.01 g/d) compared to the RDIs. However, 30% of the forest workers and 66% of the researchers reported consuming less protein than the RDIs. The percentage of daily intake of carbohydrates was considerably lower than the RDIs for both groups. Consequently, the daily energy intake derived from carbohydrates was only 31.59% and 37.11% for forest workers and researchers, respectively. However, in a traditional Greek menu, carbohydrates contribute 41% to the daily energy intake [25]. This insufficient carbohydrates intake may cause inability of energy supply from glucose, and this may lead to protein catabolism. This condition may have significant implications for the worker in a heavy occupation such as harvesting timber.
The daily total lipid intake exceeded the RDIs for both groups, with forest workers having almost double the daily intake at 192.7% of RDI. Their contribution to the total energy intake was slightly higher than that of a traditional Greek menu for both groups. It was 42.45% and 44.69% for forest workers and researchers, respectively, whereas the contribution of total lipids to daily energy intake was 40.3% [24]. This may be due to the extensive use of olive oil for salads, for frying, and preparing main meals. The daily PUFA intake of 10.57 and 8.64 g for forest workers and researchers, respectively, was higher than proposed by the Scientific Committee for Food of the European Commission, which for adults is on average 3.3 g/d [26]. Along with high dietary intakes of PUFA, it is important to ensure that the intake of vitamin E is adequate because an increased intake of PUFA raises the need for vitamin E to prevent unwanted oxidation. There is no general agreement about what the ratio in milligrams of a-tocopherol equivalents per gram of PUFA should be, but about 0.4 seems adequate in a normal diet [25,24]. The ratio in milligrams of a-tocopherol per gram of PUFA was 0.8 for forest researchers and 1.0 for researchers, indicating that the diets were balanced for all nutrients. Taking into consideration the RDI guidelines and the daily fiber intake of a traditional Greek menu, accounting for about 29.8 g [24], it was found that both groups had lower intake, that is, 19.95 and 15.4 g for forest workers and researchers, respectively. Alcohol intake was high in forest workers (41.11 g/d), contributing about 8.37% of the total energy intake and more than 3 times higher than that of the 14 g of the traditional Greek menu [24]. This energy contribution of alcohol is higher than the 1.3% reported for Chilean forest workers [9,27] and lower that the 14% in German forest workers [8]. Despite alcohol being a high-energy macromolecule, alcoholic beverages have little nutritional value [28], usually replace the carbohydrate part of the meal [29], and alter lipid metabolism by inhibiting lipolysis [30]. Vitamin C for both forest workers and researchers exceeded the RDIs at 211.09% and 172.5%, respectively. This may due to the sufficient daily intake of fruits. Vitamin A intake for researchers was higher than the RDI, whereas forest workers had an intake 6% lower than the RDIs. Vitamin D intake was lower than the RDIs for both groups, meeting only 23.56% and 14.48% of the RDIs for forest workers and researchers, respectively. This may be a possible factor for vitamin D deficiency. This is more pronounced for researchers because in comparison with forest workers, they do not expose themselves very much to sunlight by working in an office. Deficient or insufficient serum vitamin D levels are associated in adults with osteomalacia [31], which leads to muscular weakness in addition to weak bones, and other diseases as well [32,33]. Sodium intake of forest workers and researchers exceeded the guidelines for daily sodium intake (less than
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2300 mg) recommended by the American Heart Association and United States Department of Health and Human Services to prevent or delay the onset of high blood pressure and to eliminate hypertension [34,35], a leading cause of death in developed countries [36]. A Finnish study reported a statistically significant direct association of increased sodium intake with coronary heart disease, cardiovascular and all-cause mortality, independently of other cardiovascular risk factors, including blood pressure [37]. It is worth mentioning here that the 24-hour dietary recall method may underestimate the actual sodium intake. This is supported by the study of Cohen et al [38], who reported that in their study with 24-hour dietary recall, the mean sodium intake was 18% lower than the measured sodium by 24-hour urinary excretion. Although the Mediterranean diet is characterized by consumption of fish, a source of iodine, iodine daily intake was extremely insufficient in both groups. This may cause various health problems [39]. Adults need iodine in amounts of 150 lg/d [40], whereas that estimated in our study was at 9.66 lg for forest workers and 4.08 lg for researchers. In conclusion, it is necessary to redress nutrient deficiencies and to prevent the appearance of negative health effects among forest workers. This may be realized by improving the daily nutrient intake. Increasing their energy and carbohydrate intake by improving and enriching their daily diet appropriately is essential. As for researchers, their sedentary working conditions, along with the high total lipid intake—including cholesterol and saturated fatty acids—and increased BMI, calls for an immediate change of daily diet. References [1] ILO. Occupational safety and health in forestry. Geneva7 International Labour Office, Sectoral activities programme, Forestry and Wood Industries Committee, Report III; 1991. [2] Donalson MS. Nutrition and cancer: a review of the evidence for an anti-cancer diet. J Nutr 2004;3:1 - 21. [3] Howe GR, Aronson KJ, Enrique B, Castelleto R, Cornee J, Duffy S, et al. The relationship between dietary fat intake and risk of colorectal cancer: evidence from the combined analysis of 13 case-control studies. Cancer Causes Control 1997;8:215 - 28. [4] Karpanen H, Mervaala E. Sodium intake and hypertension. Prog Cardiovasc Dis 2006;49(2):59 - 75. [5] Bazzano LA, Serdula MK, Liu S. Dietary intake of fruits and vegetables and the risk of cardiovascular disease. Curr Atheroscler Rep 2003;5(6):492 - 9. [6] Hung HC, Joshipura KJ, Jiang R, Hu FB, Hunter D, Smith-Warner SA, et al. Fruit and vegetable intake and risk of major chronic disease. J Natl Cancer Inst 2004;96(21):1577 - 84. [7] Apud E, Bostrand L, Mobbs ID, Bernt-Strehle A. Guide-lines on ergonomic study in forestry. Geneva7 International Labour Office; 1989. [8] Wirths W. Research on energy and nutrient requirements and on nutrient supply of workers with different energy expenditure. In: Debry G, Bleyer R, editors. Alimentation et travail. Paris7 Maison et cie; 1972. [9] Apud E. A human biological field study of Chilean forestry workers. Doctoral thesis, Loughborough University, U.K., 1983.
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Nutrient intakes of Greek forest workers and researchers do not meet all Reference Dietary Intakes Christos Gallis4, Panayota Panagopoulou Forest Research Institute, Vasilika, 57 006 Thessaloniki, Greece Received 9 February 2007; revised 6 April 2007; accepted 13 April 2007
Abstract In heavy work such as forest work, nutrient demand and energy expenditure are high. Therefore, adequate nutrient and energy intake of forest workers is of paramount importance. The objective of this cross-sectional study was to investigate the daily nutrient intake of forest workers and to determine if it meets the Reference Dietary Intakes (RDIs). A total of 21 forest workers and 21 researchers, who served as a control group, were enrolled. Nutrient intake was assessed on the basis of a 24-hour diet recall questionnaire, repeated for 3 consecutive weekdays. Daily nutrient intake was calculated using the NutriBase IV Clinical Edition Software package. Energy, protein, total lipids, saturated fatty acids, cholesterol, phosphorus, and sodium intake of forest workers was higher than the RDIs and significantly higher ( P b .05) than that of researchers. Most forest workers (90.47%) and researchers (95.32%) consumed less carbohydrate than the RDIs. Dietary fiber, riboflavin, vitamin E, vitamin D, and minerals intake was less than the RDI in both groups. Especially low was the daily intake of vitamin D and iodine in forest workers in comparison to RDIs and researchers. The results indicate that fundamental changes in daily nutrient intake for both groups are recommended. D 2007 Elsevier Inc. All rights reserved. Keywords:
Human; Nutrient intake; Greek; Forest workers; Researchers
1. Introduction Physically heavy work is still widespread among forest operators working in harvesting timber. To keep forestry workers in a good state of health and productivity, daily nutrition quality and quantity should be adequate and balanced [1]. Nutrition plays a major role in human health [2-6]. In forest work, which is heavy work, the nutrient demand and energy expenditure are high. Therefore, adequate nutrient and energy intake of forest workers is of paramount importance. If daily energy expenditure is higher than the energy intake, subsequently the energy balance becomes negative. Few quantitative studies, which are summarized in 4 Corresponding author. Tel.: +30 231 0 461 172x216; fax: +30 231 0 461 341. E-mail address: [email protected] (C. Gallis). 0271-5317/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.nutres.2007.04.005
an International Labor Office publication in 1989 [7], have assessed the daily energy intake of forest workers in different countries. According to the previously mentioned International Labor Office publication, in Finland (1960), an average daily energy intake of 4763 kcal per 24 hours was reported; in Canada (1973), daily meals provided 5500 kcal; and in the Netherlands (1972), a daily energy intake of 4260 kcal was calculated. In a study on German forest workers [8], it was reported that daily meals provided 4530 kcal on average. In Chile, during a case study of 57 forestry workers, a mean daily energy intake of 3519 kcal and an energy expenditure of 3541 kcal were recorded [9]. However, all this information has been collected mostly in Nordic countries, whereas such information for Mediterranean countries is sparse. Despite the known role of nutrition in human health worldwide, there are no current studies describing the daily
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Table 1 Anthropometric, demographic, and body composition characteristics of forest workers and researchers Variable Age (y) Weight (kg) Height (m) BMI (kg/m2) BMR (kcal)
Forest workers 42.3 F 11.1 78.2 F 18 1.80 F 0.1 24.13 F 3.00 1759 F 210
Researchers 51 F 6.6 89.9 F 11 1.74 F 0.05 29.69 F 3.4 1681.4 F 124
Values are means F standard deviation (n = 21).
nutrient intake of forest workers and researchers. This is also the case in Greece, where nutrient intake analysis of forest workers and researchers has not received any attention. In fact, forest work in Greece is characterized by heavy manual tasks on steep mountain slopes requiring high physical effort. Thus, it is essential to determine if workers have adequate daily nutrient intake meeting the Reference Dietary Intakes (RDIs). The objective of this study was to investigate the daily nutrient intake, by using a 24-hour recall assessment method, of forest workers and researchers and to determine if it meets the RDIs. 2. Methods and materials 2.1. Study population A sample of 21 male forest workers from the village of Sideronero in the Drama region of Northern Greece and 21 researchers from the National Agricultural Research Foundation’s Research Institutes of Thessaloniki (serving as a control group), matched for age and sex, was investigated (Table 1). They were randomly selected from a list of 53 male researchers and 120 forest workers.
The forest workers were self-employed in timber harvesting, a rather energy-intensive job in steep mountain forests characterized by vigorous physical activity [10]. The level of their education was of that of elementary school. In contrast, the researchers’ group was characterized by sedentary physical activities, holding a PhD degree, mostly spending daily working time in office, and computer work [10]. Only male forest workers and researchers participated because no female work professionally in timber-harvesting operations in Greece. The study was carried out in the summer of 2004. Each subject was interviewed individually in a private one-on-one interview. All the interviews were performed by the first author. Approval to implement the study protocol was obtained from the Forest Research Institute Scientific Committee and for human subject use from the local Ethics Committee of Drama Regional Authority. 2.2. Anthropometry and body composition Body weight, height, and body mass index (BMI; kg/m2) were measured. To estimate basic energy needs of the participants, the basal metabolic rate (BMR) was calculated using bioelectrical impedance analysis (MALTRON BF900) (Table 1) according to the European guidelines for bioelectrical impedance analysis [11]. 2.3. Nutrient intake calculation procedure Nutrient intake was assessed on the basis of a 24-hour diet recall questionnaire [12-18], repeated for 3 consecutive weekdays [7,13,14], using a semistructured diary. Individual interviews of each participant were conducted to record the nutrient intake of the previous day. The interviews were
Table 2 Energy and macronutrient daily intakes and percentage of RDI of the forest workers and researchers Nutrients Energy intake (kcal) Protein (g) Calories from protein % calories from protein Carbohydrate (g) Calories from carbohydrates % calories from carbohydrates Total lipid (fat) (g) Calories from fat % calories from fat Fatty acids, saturated (g) Fatty acids, monounsaturated (g) Fatty acids, polyunsaturated (g) Fatty acids, total trans (g) Omega-3 (g) Omega-6 (g) Cholesterol (mg) Fiber, total dietary (g) Water (g) Alcohol (g)
Mean F SD Forest workers 2705.97 F 1089.714 101.37 F 39.024 400.95 F 152.864 15.26 F 3.31 223.06 F 109.44 881.49 F 429.01 31.59 F 6.404 128.08 F 57.564 139.44 F 509.114 42.40 F 7.23 35.53 F 20.45 56.46 F 23.584 10.57 F 4.054 0.35 F 0.85 1.68 F 1.014 6.99 F 2.634 330.98 F 145.034 19.95 F 19.32 2238.72 F 1999.194 41.11 F 35.864
Percentage of RDI Researchers 1857.98 F 542.75 70.01 F 17.02 276.56 F 66.93 15.38 F 3.21 178.59 F 73.59 703.82 F 284.81 37.11 F 9.14 93.15 F 33.44 827.89 F 297.74 44.69 F 7.64 8.60 F 8.76 39.38 F 16.79 8.64 F 2.74 0.33 F 1.02 0.74 F 0.46 5.47 F 2.47 237.19 F 94.36 15.43 F 10.93 1244.5 F 691.66 7.18 F 6.74
Forest workers 113.88 F 0.504 112.85 F 0.414
Researchers 83.71 F 0.30 83.47 F 0.24
61.95 F 0.31
54.00 F 0.25
192.70 F 0.904
51.10 F 0.63
160.97 F 0.98
138.83 F 0.51
139.16 F 0.634 79.99 F 0.70 73.34 F 0.634
106.74 F 0.47 70.95 F 0.54 43.02 F 0.25
4 Denotes statistically significant difference from researchers at P V .05 as determined by unpaired t test (n = 21).
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Table 3 Vitamin daily intakes and percentage of RDI of the forest workers and researchers Vitamin Vitamin A (IU) Thiamine (mg) Riboflavin (mg) Niacin (mg) Pantothenic acid (mg) Vitamin B6 (mg) Folate (lg) Folic acid (lg) Vitamin B12 (lg) Vitamin C (mg) Vitamin D (IU) Vitamin E (IU)
Mean F SD Forest workers 4700.89 F 4614.89 0.90 F 0.39 1,39 F 0.54 21.81 F 10.074 4.20 F 4.16 2.07 F 1.304 247.66 F 231.65 2 8.21 F 42.31 9.07 F 5.144 126.64 F 130.22 47.10 F 62.63 13.91 F 6.38
Percentage of RDI Researchers 6479.99 F 10953.06 0.75 F 0.33 1.30 F 0.43 11.99 F 4.34 2.81 F 1.29 1.27 F 0.39 201.60 F 89.33 34.58 F 39.50 3.26 F 2.29 103.50 F 65.58 28.96 F 26.36 12.97 F 8.72
Forest workers 94.01 F 0.92 64.31 F 0.27 86.61 F 0.35 123.69 F 0.594
Researchers 129.59 F 2.19 58.51 F 0.29 86.43 F 0.31 72.50 F 0.26
103.29 F 0.654 123.83 F 1.15
63.49 F 0.19 100.83 F 0.44
453.53 F 211.09 F 23.56 F 93.39 F
163.03 172.50 14.48 87.09
2.574 2.17 0.31 0.42
F F F F
1.14 1.09 1.13 0.58
4 Denotes statistically significant difference from researchers at P V .05 as determined by unpaired t test (n = 21).
structured to assist the participants in recalling all foods and beverages consumed throughout the day. Participants who received vitamin and mineral supplements were excluded. In the diaries, days were segmented into 6 eating occasions, namely breakfast, between breakfast and lunch, lunch, between lunch and dinner, dinner, after dinner, and any snack eaten throughout the day. Information on the type, including brand names, and amount of food consumed was collected. After completion, food models were used to quantify portions [19,20]. For each subject, separately, the nutrient intake was calculated using the NutriBase IV Clinical Edition Software package [21], which also contains the United States Department of Agriculture Nutrient Database for Standard References. Nutribase IV software was used because no local software exists. The software also calculated the calories derived from protein, carbohydrates, and total lipids as the percentage of the daily RDI for each subject. The percentage contribution of dietary fibers and alcohol to total energy intake was calculated by application of the general Atwater energy conversion factors 2-7, respectively [22].
2.4. Statistical methods Descriptive statistics are expressed as mean values and standard deviations (mean F SD) [23]. Comparison of mean values between forest workers and researchers was conducted using the unpaired t test to define differences between the 2 groups. All analyses were performed using the statistical package SPSS [23]. Statistical significance was set at P V .05.
3. Results and discussion This study, which treats the nutrient intake and energy expenditure in a demanding energy occupation such as forest work, revealed significant nutrient deviations from the RDI recommendations. Forest workers had unexpectedly lower daily intake than the RDIs in carbohydrates, fibers, iodine, water, and part of vitamins such as A, D, E, thiamine, and riboflavin (Tables 2-4). They had higher than recommended daily intake of protein, total lipids, saturated fatty acids, cholesterol, niacin, vitamin B6, total folate, vitamin B12, and
Table 4 Mineral daily intakes and percentage of RDI for forest workers and researchers Nutrient Calcium (mg) Chromium (lg) Copper (mg) Fluoride (mg) Iodine (lg) Iron (mg) Magnesium (mg) Manganese (mg) Molybdenum (lg) Phosphorus (mg) Potassium (mg) Selenium (lg) Sodium (mg) Zinc (mg)
Mean F SD Forest workers 705.71 F 472.40 10.62 F 7.814 0.97 F 0.59 0.11 F 0.104 14.50 F 16.574 9.01 F 5.56 248.38 F 215.15 2.40 F 2.534 0.21 F 0.97 1076.61 F 495.104 2954.76 F 2447.10 61.86 F 27.234 3738.22 F 4228.88 7.24 F 3.92
Percentage of RDIs Researchers 695.45 F 235.76 5.21 F 3.58 0.76 F 0.41 0.04 F 0.02 6.13 F 5.85 7.97 F 4.08 166.63 F 61.29 1.33 F 0.72 0.29 F 1.01 817.81 F 226.25 2272.03 F 1225.35 43.98 F 15.94 2401.10 F 693.04 6.63 F 2.76
4 Denotes statistically significant difference ( P b .05) from the researchers (n = 21).
Forest workers 88.22 F 0.59
Researchers 86.93 F 0.29
9.66 F 0.114 90.10 F 0.55 70.96 F 0.60
4.08 F 0.03 79.701 F 0.40 47.61 F 0.17
134.59 F 0.614
102.22 F 0.28
88.38 F 0.384 163.96 F 1.75 48.23 F 0.26
62.83 F 0.22 109.52 F 0.35 44.22 F 0.18
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vitamin C (Tables 2 and 3). The total lipids intake was indeed high, but the quality of lipids was of high value because it resulted from the content in polyunsaturated fatty acid (PUFA) (Table 2). It is notable that the daily intake of sodium highly exceeded the RDI (Table 4). Regarding the total energy in calories, it was found that the forest workers had a higher intake than the RDI (Table 2). In the control group consisting of researchers, lower energy, protein, carbohydrate, fiber, and water intake than the RDIs as well as lower than those of forest workers were found (Table 2). Differences in BMI and BMR between the 2 groups were observed, with forest workers having lower BMI and higher BMR than researchers. Basal metabolic rate of forest workers was calculated at 1759 kcal/d. This represents the amount of energy expended while at rest in a neutrally temperate environment in the postabsorptive state [24]. In this study, the energy intake of forest workers was calculated to be 2705.97 kcal/d. This intake meets and exceeds the requirements for light work but not the needs for very active, heavy work such as that of forest workers performed in our study. Moreover, it is lower than that calculated by Apud et al [7] for Chilean forest workers, which was 3432 kcal during weekdays. According to the Food and Agriculture Organization [10], for very active forest workers, the energy expenditure per hour of work is 240 kcal. The average working hours of forest workers in our study were about 9 hours per day; thus, the energy expenditure during work is estimated at 2160 kcal. It means that the total energy intake needed to cover the BMR requirements and the energy for work is estimated at 3919 kcal. Thus, the deficiency in energy is estimated at 1193 kcal. On the other hand, the group of researchers in our study does light office work and their energy requirements are not as high as for forest workers. The BMR was calculated at 1681.4 kcal. Their energy intake was calculated at 1857.98 kcal, which is below the daily recommended intake for light work [10]. Forest workers meet the RDIs for protein intake, with 101.37 g/d, which is in agreement with that reported for Chilean forest workers’ intake of 109.7 g/d [7], whereas researchers had a lower protein intake (70.01 g/d) compared to the RDIs. However, 30% of the forest workers and 66% of the researchers reported consuming less protein than the RDIs. The percentage of daily intake of carbohydrates was considerably lower than the RDIs for both groups. Consequently, the daily energy intake derived from carbohydrates was only 31.59% and 37.11% for forest workers and researchers, respectively. However, in a traditional Greek menu, carbohydrates contribute 41% to the daily energy intake [25]. This insufficient carbohydrates intake may cause inability of energy supply from glucose, and this may lead to protein catabolism. This condition may have significant implications for the worker in a heavy occupation such as harvesting timber.
The daily total lipid intake exceeded the RDIs for both groups, with forest workers having almost double the daily intake at 192.7% of RDI. Their contribution to the total energy intake was slightly higher than that of a traditional Greek menu for both groups. It was 42.45% and 44.69% for forest workers and researchers, respectively, whereas the contribution of total lipids to daily energy intake was 40.3% [24]. This may be due to the extensive use of olive oil for salads, for frying, and preparing main meals. The daily PUFA intake of 10.57 and 8.64 g for forest workers and researchers, respectively, was higher than proposed by the Scientific Committee for Food of the European Commission, which for adults is on average 3.3 g/d [26]. Along with high dietary intakes of PUFA, it is important to ensure that the intake of vitamin E is adequate because an increased intake of PUFA raises the need for vitamin E to prevent unwanted oxidation. There is no general agreement about what the ratio in milligrams of a-tocopherol equivalents per gram of PUFA should be, but about 0.4 seems adequate in a normal diet [25,24]. The ratio in milligrams of a-tocopherol per gram of PUFA was 0.8 for forest researchers and 1.0 for researchers, indicating that the diets were balanced for all nutrients. Taking into consideration the RDI guidelines and the daily fiber intake of a traditional Greek menu, accounting for about 29.8 g [24], it was found that both groups had lower intake, that is, 19.95 and 15.4 g for forest workers and researchers, respectively. Alcohol intake was high in forest workers (41.11 g/d), contributing about 8.37% of the total energy intake and more than 3 times higher than that of the 14 g of the traditional Greek menu [24]. This energy contribution of alcohol is higher than the 1.3% reported for Chilean forest workers [9,27] and lower that the 14% in German forest workers [8]. Despite alcohol being a high-energy macromolecule, alcoholic beverages have little nutritional value [28], usually replace the carbohydrate part of the meal [29], and alter lipid metabolism by inhibiting lipolysis [30]. Vitamin C for both forest workers and researchers exceeded the RDIs at 211.09% and 172.5%, respectively. This may due to the sufficient daily intake of fruits. Vitamin A intake for researchers was higher than the RDI, whereas forest workers had an intake 6% lower than the RDIs. Vitamin D intake was lower than the RDIs for both groups, meeting only 23.56% and 14.48% of the RDIs for forest workers and researchers, respectively. This may be a possible factor for vitamin D deficiency. This is more pronounced for researchers because in comparison with forest workers, they do not expose themselves very much to sunlight by working in an office. Deficient or insufficient serum vitamin D levels are associated in adults with osteomalacia [31], which leads to muscular weakness in addition to weak bones, and other diseases as well [32,33]. Sodium intake of forest workers and researchers exceeded the guidelines for daily sodium intake (less than
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2300 mg) recommended by the American Heart Association and United States Department of Health and Human Services to prevent or delay the onset of high blood pressure and to eliminate hypertension [34,35], a leading cause of death in developed countries [36]. A Finnish study reported a statistically significant direct association of increased sodium intake with coronary heart disease, cardiovascular and all-cause mortality, independently of other cardiovascular risk factors, including blood pressure [37]. It is worth mentioning here that the 24-hour dietary recall method may underestimate the actual sodium intake. This is supported by the study of Cohen et al [38], who reported that in their study with 24-hour dietary recall, the mean sodium intake was 18% lower than the measured sodium by 24-hour urinary excretion. Although the Mediterranean diet is characterized by consumption of fish, a source of iodine, iodine daily intake was extremely insufficient in both groups. This may cause various health problems [39]. Adults need iodine in amounts of 150 lg/d [40], whereas that estimated in our study was at 9.66 lg for forest workers and 4.08 lg for researchers. In conclusion, it is necessary to redress nutrient deficiencies and to prevent the appearance of negative health effects among forest workers. This may be realized by improving the daily nutrient intake. Increasing their energy and carbohydrate intake by improving and enriching their daily diet appropriately is essential. As for researchers, their sedentary working conditions, along with the high total lipid intake—including cholesterol and saturated fatty acids—and increased BMI, calls for an immediate change of daily diet. References [1] ILO. Occupational safety and health in forestry. Geneva7 International Labour Office, Sectoral activities programme, Forestry and Wood Industries Committee, Report III; 1991. [2] Donalson MS. Nutrition and cancer: a review of the evidence for an anti-cancer diet. J Nutr 2004;3:1 - 21. [3] Howe GR, Aronson KJ, Enrique B, Castelleto R, Cornee J, Duffy S, et al. The relationship between dietary fat intake and risk of colorectal cancer: evidence from the combined analysis of 13 case-control studies. Cancer Causes Control 1997;8:215 - 28. [4] Karpanen H, Mervaala E. Sodium intake and hypertension. Prog Cardiovasc Dis 2006;49(2):59 - 75. [5] Bazzano LA, Serdula MK, Liu S. Dietary intake of fruits and vegetables and the risk of cardiovascular disease. Curr Atheroscler Rep 2003;5(6):492 - 9. [6] Hung HC, Joshipura KJ, Jiang R, Hu FB, Hunter D, Smith-Warner SA, et al. Fruit and vegetable intake and risk of major chronic disease. J Natl Cancer Inst 2004;96(21):1577 - 84. [7] Apud E, Bostrand L, Mobbs ID, Bernt-Strehle A. Guide-lines on ergonomic study in forestry. Geneva7 International Labour Office; 1989. [8] Wirths W. Research on energy and nutrient requirements and on nutrient supply of workers with different energy expenditure. In: Debry G, Bleyer R, editors. Alimentation et travail. Paris7 Maison et cie; 1972. [9] Apud E. A human biological field study of Chilean forestry workers. Doctoral thesis, Loughborough University, U.K., 1983.
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