The intake of tubers among tuber consumers in rural and urban areas across the five Brazilian macroregions is presented in Table 1. Fifty-five percent (18,901 people) of the total Brazilian population consumed at least one tuber containing food during the two-day survey period. Across all Brazil, rural and urban areas contained 58 and 54% tuber consumers, respectively. Tuber consumers in rural areas across Brazil ate significantly more tubers (mean: 127 g/day) as part of their diets than those in urban areas (mean: 96 g/day). Fifty-one percent of people in the Southeast consumed tubers compared to 55% in the Northeast macroregion. Of all macroregions, the highest tuber consumption among tuber consumers was noted in the North (mean: 112 g/day), followed by the South (mean: 109 g/day). Tuber intakes in these regions were significantly (P < 0.001) higher than in the Southeast and Central-West. The lowest intakes of tubers across all macroregions were found in the Central-West (mean: 88 g/day) and the Southeast (98 g/day). The tuber consumption in these regions was significantly (P < 0.001) lower than in the North and South. Differences in the tuber intakes between urban and rural areas were found across all macroregions, with significantly higher (P < 0.001) intakes noted in rural areas. Specifically, the North rural area consumed the highest amounts of tubers (mean: 156 g/day), while the Central-West urban area consumed the lowest amounts of tubers (mean: 84 g/day).
Table 1
Intake of tubers in Brazil according to regional and sociodemographic characteristics.
Regions | Number of Tuber Consumers | Intake by Tuber Consumers (g/day) | Prevalence of tuber consumers (%) |
| | Median | Mean | SD | |
All Brazil | | 18,901 | 78 | 101 | 102 | 54.7 |
Female | | 10,070 | 72 | 95*** | 93 | 54.7 |
Male | | 8,831 | 80 | 108*** | 110 | 54.7 |
10–12 years | | 1,182 | 66 | 93***b | 103 | 54.1 |
13–18 years | | 2,415 | 72 | 99ab | 107 | 50.7 |
19–34 years | | 6,073 | 80 | 103**a | 103 | 54.2 |
35–49 years | | 4,646 | 80 | 102***a | 100 | 57.1 |
50–65 years | | 3,045 | 75 | 102** a | 103 | 56.8 |
66 + years | | 1,540 | 80 | 100**a | 93 | 52.2 |
Rural | | 4,807 | 95 | 127*** | 127 | 58.1 |
Urban | | 14,094 | 74 | 96*** | 95 | 54 |
Income − 1st quintile$ | | 3,251 | 80 | 108***a | 110 | 51.7 |
Income − 2nd quintile$ | | 3,537 | 80 | 109ab | 112 | 51.1 |
Income − 3rd quintile$ | | 3,905 | 80 | 101ab | 97 | 52.8 |
Income − 4th quintile$ | | 4,087 | 80 | 104**b | 110 | 55.9 |
Income − 5th quintile$ | | 4,121 | 71 | 91***c | 87 | 59 |
North | | 3,404 | 80 | 112***b | 115 | 73.1 |
Rural | | 1,137 | 102 | 156*** | 154 | 80.3 |
Urban | | 2,267 | 71 | 92*** | 87 | 70.4 |
Northeast | | 6,872 | 70 | 102***bc | 107 | 54.6 |
Rural | | 1,737 | 80 | 118*** | 130 | 57.7 |
Urban | | 5,135 | 66 | 95*** | 95 | 53.4 |
Southeast | | 3,889 | 80 | 98***c | 93 | 51.4 |
Rural | | 754 | 95 | 117*** | 100 | 48.2 |
Urban | | 3,135 | 80 | 96*** | 92 | 51.7 |
South | | 2,332 | 88 | 109***a | 105 | 55.8 |
Rural | | 602 | 102 | 135*** | 112 | 60.5 |
Urban | | 1,730 | 84 | 104*** | 103 | 54.9 |
Central-West | | 2,404 | 53 | 88***d | 103 | 54.3 |
Rural | | 577 | 80 | 119*** | 121 | 46.1 |
Urban | | 1,827 | 51 | 84*** | 101 | 55.4 |
Significant differences (**P < 0.01; ***P < 0.001) between genders and age and income groups across all tuber consumers in Brazil/macroregions, as well as urban and rural areas within macroregions; Means that do not share the same letter are significantly different to each other; SE: standard deviation; $ Household monthly income (R$). |
Differences in mean consumption between genders and age groups across all tuber consumers in Brazil were observed. Male consumers were significantly (P < 0.001) associated with increased intake of tubers. In relation to age, consumers 10–12 years were significantly (P < 0.01) associated with lower intake values when compared to the consumers aged 19 years onwards. Tuber consumption of individuals aged 13–18 years did not significantly differ from other groups. Differences in mean intakes between income groups across all tuber consumers in Brazil were found. The highest (108 g/day) and lowest (91 g/day) mean daily intakes of tubers were noted amongst consumers from first- and fifth-income quintiles (P < 0.001) (the first quintile being lowest vs. fifth quintile being highest income group).
The intake of specific tuber types among tuber consumers in rural and urban areas across all Brazilian macroregions is shown in Table 2. Mandioca and potato were the most prevalent tubers in Brazil (59 and 43%, respectively). Consumption of mandioca was more prevalent amongst consumers in rural than in urban areas (76 and 55%, respectively). There were twice as many potato consumers in urban than in rural areas (47 and 24%, respectively). Sweet potato and yam were the least commonly consumed tubers in Brazil (3.8 and 3.5%, respectively). Sweet potato consumption was lower in urban areas than in rural areas (3.3 and 6.2%, respectively), while yams consumption was less disparate (3.3 and 3.5%, respectively). However, among consumers of each type, the highest daily intake across all of Brazil was noted for sweet potato, followed by potato and yam (mean: 156, 95, and 84 g/day, respectively).
Table 2
Intake of tuber types in rural and urban areas across Brazilian macroregions.
Region | Mandioca | Potato | Sweet Potato | Carrot | Yam | Beet |
| % consuming | g/day among consumers | % consuming | g/day among consumers | % consuming | g/day among consumers | % consuming | g/day among consumers | % consuming | g/day among consumers | % consuming | g/day among consumers |
All Brazil | 59 | 77 | 43 | 95 | 3.8 | 156 | 11 | 30 | 3.5 | 84 | 4.6 | 50 |
Rural | 76 | 110*** | 24 | 99*** | 6.2 | 191 | 5.6 | 34 | 3.3 | 90 | 2.4 | 57 |
Urban | 55 | 67*** | 47 | 95*** | 3.3 | 141 | 12 | 29 | 3.5 | 83 | 5.1 | 49 |
North | 94 | 104***a | 14 | 80***c | 0.5 | 114**ab | 3.7 | 25***c | 0.6 | 108 | 1.1 | 56**ab |
Rural | 96 | 154*** | 8 | 79*** | 0.2 | 117 | 1 | 21 | 1.5 | 98 | 0.6 | 99 |
Urban | 93 | 82*** | 16 | 80*** | 0.6 | 114 | 4.9 | 25 | 0.2 | 135 | 1.3 | 47 |
Northeast | 83 | 81***b | 16 | 73***c | 8 | 180**a | 3 | 24***c | 7.8 | 84 | 1.3 | 103**a |
Rural | 88 | 99*** | 7.5 | 68 | 9.4 | 222 | 1.3 | 33 | 4.2 | 94 | 0.3 | 156 |
Urban | 81 | 73*** | 19 | 74 | 7.5 | 159 | 3.6 | 22 | 9.2 | 82 | 1.7 | 99 |
Southeast | 42 | 55***d | 63 | 99***a | 1.6 | 123**ab | 15 | 32***a | 3 | 84 | 5.9 | 42**b |
Rural | 54 | 80*** | 55 | 108** | 3.4 | 99 | 9.1 | 47 | 5.5 | 75 | 4.2 | 45 |
Urban | 41 | 52*** | 64 | 98** | 1.4 | 127 | 15 | 30 | 2.8 | 85 | 6 | 42 |
South | 34 | 84***c | 62 | 103***a | 4.6 | 128**b | 21 | 30***ab | 0.1 | 66 | 8.4 | 42**b |
Rural | 44 | 123*** | 56 | 109 | 7.8 | 134 | 19 | 28 | 0 | 0 | 8.1 | 48 |
Urban | 32 | 74*** | 64 | 102 | 3.9 | 126 | 22 | 30 | 0.1 | 66 | 8.4 | 40 |
Central-West | 68 | 72***c | 35 | 76***b | 2.9 | 93**b | 13 | 27***b | 0.9 | 82 | 7.3 | 65**ab |
Rural | 76 | 114*** | 28 | 72 | 2.1 | 120 | 10 | 24 | 3.3 | 118 | 4.9 | 69 |
Urban | 67 | 67*** | 36 | 77 | 3 | 91 | 14 | 28 | 0.6 | 60 | 7.6 | 64 |
Significant difference (**P < 0.01, ***P < 0.001) between macroregions/urban and rural areas within macroregions; Means that do not share the same letter are significantly different to each other; % of prevalence amongst consumers. |
On a macroregion level, the most commonly consumed tubers in the Northeast were mandioca (83%), potato (16%), and sweet potato (8%), while in the Southeast, the most popular tubers were potato (63%), mandioca (42%) and carrot (15%). The most commonly consumed tubers in the South, which is the third most populated region concentrating 15% of the Brazilian population [6], were potato (62%), mandioca (34%), and carrot (21%). The highest intakes of mandioca (mean:104 g/day) were observed in the North, while the highest intakes of potato were noted in the South (mean: 103 g/day). For sweet potato and beet, the highest consumption was found in the Northeast (mean:180 and 103 g/day, respectively). Lastly, the highest intakes of carrot were observed in the Southeast (mean: 32 g/day). Concerning differences in the consumption of tuber types among tuber consumers in rural and urban areas (Table 2), statistical analysis revealed that increased mandioca consumption was significantly (P < 0.001) associated with rural areas across all five macroregions. Moreover, potato intakes in the Southeast rural area were significantly (P < 0.01) higher than those in the urban areas.
Regional differences in the preparation methods of tubers are shown in Fig. 1. This analysis aimed to explore tuber consumption habits in terms of the preparation methods amongst consumers living across the Brazilian macroregions. Mandioca was consumed in cooked dishes either whole and in the form of flour or starch, with the highest proportion of mandioca flour being consumed in the North, followed by Northeast and Southeast. Potato, sweet potato, and yam were consumed in dishes that incorporate the whole tuber across all five macroregions. Beet was consumed whole and as a juice, with the highest proportion of juice being in the Northeast region, followed by North and Central-West. While carrot was primarily consumed as a whole, a small proportion of juice consumption was observed in the Northeast, Southeast, South, and Central-West.
Nutrient intake of tuber consumers and non-tuber consumers across Brazil is shown in Table 3. Differences in energy intake (kcal/day) were significantly (P < 0.001) associated with tuber consumption, where individuals that consumed tubers had 16% higher energy intake per day when compared to non-tuber consumers. The regression analysis adjusted by sociodemographic variables also identified small but significant differences among tuber and non-tuber consumers in nutrients intakes.
Table 3
Nutrient intake of tuber consumers and non-tuber consumers across Brazil.
Nutrient (unit) | Mean Intakes (SE) | │Δ Mean Intakes│(%) |
| Tuber Consumers N = 18,901 | Non-Tuber Consumers N = 14,603 | |
Energy (kcal/day) | 1848 (0.003) | 1600 (0.003) | 248 (15.5)*** |
Macronutrients | | | |
Protein (g/day) | 83.3 (0.003) | 75.5 (0.004) | 7.8 (10.3)*** |
Protein (g/1000 kcal) | 45.4 (0.002) | 47.4 (0.002) | 2 (4.2)*** |
Total Fat (g/day) | 57.5 (0.004) | 50.1 (0.004) | 7.4 (14.8)*** |
Total Fat (g/1000 kcal) | 30.8 (0.002) | 30.9 (0.002) | 0.09 (0.3) |
Carbohydrates (g/day) | 247 (0.003) | 209 (0.003) | 37.2 (17.7)*** |
Carbohydrates (g/1000 kcal) | 134 (0.001) | 132 (0.001) | 2.3 (1.7)*** |
Total Fiber (g/day) | 21.1 (0.004) | 18.4 (0.004) | 2.7 (14.6)*** |
Total Fiber (g/1000 kcal) | 11.7 (0.003) | 11.8 (0.003) | 0.07 (0.6)*** |
Micronutrients | | | |
Calcium (mg/1000 kcal) | 277 (0.004) | 285 (0.004) | 8.3 (2.9)*** |
Magnesium (mg/1000 kcal) | 139 (0.002) | 140 (0.003) | 0.7 (0.5) |
Manganese (mg/1000 kcal) | 2.94 (0.030) | 3.06 (0.034) | 0.12 (3.8)** |
Phosphorus (mg/1000 kcal) | 551 (0.002) | 563 (0.002) | 12.8 (2.3)*** |
Iron (mg/1000 kcal) | 6.27 (0.002) | 6.68 (0.003) | 0.41 (6.1)*** |
Sodium (g/1000 kcal) | 0.83 (0.005) | 0.89 (0.005) | 0.05 (6)*** |
Potassium (mg/1000 kcal) | 1357 (0.002) | 1339 (0.002) | 17.9 (1.3)*** |
Copper (mg/1000 kcal) | 0.75 (0.012) | 0.73 (0.013) | 0.01 (2) |
Zinc (mg/1000 kcal) | 6.18 (0.003) | 6.56 (0.003) | 0.37 (5.7)*** |
Selenium (µg/1000 kcal) | 50.7 (0.004) | 51.6 (0.005) | 0.88 (1.7)** |
Retinol (µg/1000 kcal) | 224 (0.026) | 215 (0.029) | 8.3 (3.9) |
Thiamin (vitamin B1) (mg/1000 kcal) | 0.64 (0.002) | 0.67 (0.002) | 0.03 (3.9)*** |
Riboflavin (vitamin B2) (mg/1000 kcal) | 0.89 (0.003) | 0.97 (0.003) | 0.09 (9)*** |
Niacin (vitamin B3) (mg/1000 kcal) | 8.31 (0.003) | 8.44 (0.004) | 0.13 (1.5) |
Pyridoxine (vitamin B6) (mg/1000 kcal) | 0.84 (0.002) | 0.83 (0.003) | 0.01 (1.1)*** |
Cobalamine (vitamin B12) (µg/1000 kcal) | 3.23 (0.015) | 3.14 (0.017) | 0.09 (2.7)** |
Folate (dietary equivalent) (µg/1000 kcal) | 149 (0.004) | 162 (0.004) | 12.8 (7.9)*** |
Vitamin D (calciferol) (µg/1000 kcal) | 1.91 (0.008) | 1.96 (0.009) | 0.05 (2.8)*** |
Vitamin E (total Alpha-tocopherol) (mg/1000 kcal) | 2.28 (0.003) | 2.27 (0.003) | 0.01 (0.5) |
Vitamin C (mg/1000 kcal) | 100 (0.027) | 109 (0.031) | 9 (8.3)** |
£Means were adjusted for age, gender, region, rural/urban area, and income; **P < 0.01, ***P < 0.001; SE: standard error; Absolute Δ (Difference) Mean Intakes = │Tuber Consumers – Non-Tuber Consumers│ (% Difference). |
The diet of those who include tubers contained higher intakes of all macronutrients (protein, carbohydrates, fiber, and fat). The macronutrient differences were mostly attributed to higher energy intake. Among tuber consumers, the energy-adjusted mean protein intake was 4% lower (P < 0.001), while the consumption of carbohydrates and fiber was 2% and 0.6% higher (P < 0.001) compared to non-consumers. There was no statistically significant difference in energy-adjusted fat intakes between both consumer types. The micronutrient density of the tuber containing diet was significantly (P < 0.01) altered within the Brazilian population, apart from magnesium, copper, retinol, niacin, and alpha-tocopherol remaining unchanged (P < 0.1). In particular, the tuber containing diet was found to be less dense in terms of riboflavin (9%), folate (8%), vitamin C (8%), iron (6%), sodium (6%), and zinc (6%) when compared to the diet of non-tuber consumers.