The importance of different forest management systems for people's dietary quality in Tanzania.

Context: A large body of literature has shown that forests provide nutritious foods in many low- and middle-income countries. Yet, there is limited evidence on the contributions from different types of forest and tree systems. Objectives: Here, we focus on individual trees and smaller forest patches outside established forest reserves as well as different forest management systems. Methods: We do so by combining novel high-resolution data on tree cover with 24-h dietary recall surveys from 465 women in Tanzania. Results: We show that people with more unclassified tree cover (i.e., individual trees and small forest patches) in their nearby surroundings have more adequate protein, iron, zinc, and vitamin A intakes. We also find that having a nearby forest under Participatory Forest Management (PFM) system is associated with higher adequacy levels of energy, iron, zinc and vitamin A. By contrast, tree cover within other types of forest (e.g., Government Forest Reserves and Government Forest Plantations) is not positively associated with people's dietary quality. Conclusions: Our key finding is that having individual trees, smaller forest patches and/or forest under PFM in close proximity is more beneficial for people's diets than other types of established forests. Our results highlight the nutritional importance of trees outside established forests and question the often-assumed benefits of forests if these are made inaccessible by social barriers (e.g., legislation). Finally, our results emphasize the need to distinguish between different forest management systems when studying forest-diet linkages. Supplementary Information: The online version contains supplementary material available at 10.1007/s10980-024-01961-6.

Feeding frequency and nutrient content of foods commonly consumed in the Iringa and Morogoro regions in Tanzania.

Information on the nutrient content of foods commonly consumed (especially indigenous ones) in rural communities of Tanzania is limited. A study was conducted to determine the nutrient content of foods commonly consumed in the Iringa and Morogoro regions. A survey was carried out in six representative villages to identify the types of foods and to determine the frequency of their consumption. Representative samples of the raw foods were collected from local markets and brought to the laboratory for analyses. Determination of protein was done by the micro-Kjeldahl method, fat by Soxhlet extraction and moisture by an oven-drying method. The mineral content was determined by atomic absorption spectrophotometer. The results showed that there is a wide range of foods commonly consumed in the two regions, especially legumes and vegetables. The frequency of consumption depended mainly on the season, whereby during the dry season the frequency of consumption was two to three meals per day and in the rainy season was one to two meals per day. Foods rich in fats were nuts and oil seeds, while good sources of protein included legumes, nuts and oil seeds especially pumpkin seeds, which contained 34.36 g/100 g edible portion. Indigenous vegetables such as mnavu (Solunum nigrum), twangabilidiga, mlenda (Corchorusolitarus) and mkochwe were rich in iron and calcium, with values as high as 24.78 mg iron in twangalibidiga and 812.41 mg calcium/100 g edible portion in mkunungu. Magnesium was highest in mtosi (288.58 mg) and copper was highest in mkunungu (0.49 mg). Mkochwe contained the highest amount of manganese. This study shows that foods locally produced in these regions are rich in nutrients, especially micronutrients, and therefore if consumed in adequate amounts may help to prevent dietary-related disorders.

Prevalence of anaemia in pregnant women during the last trimester.

Anaemia is a very common condition during pregnancy. This is particularly so in developing countries where the level of intake of iron rich foods is low; malaria and other intestinal parasites are common. This study was conducted to determine the prevalence of anaemia and the type of anaemia existing in pregnant women in Morogoro municipality. The effect of anaemia on infant birth weight was also examined. Twenty randomly selected pregnant women in their last trimester of pregnancy were studied. The subjects were recruited from the three maternal and child health clinics in the municipality. The subjects were not taking iron, folate or vitamin B12 supplements at the time of the study. Blood samples were collected from subjects during their routine visit to maternal and child health clinics. A series of determinations was conducted to determine haemoglobin concentration (Hb); packed cell volume (PCV); red blood cells count (RBC); serum iron (SI); and total iron binding capacity (TIBC). The effect of anaemia on the weight of new born babies was examined by calculating the correlation coefficient of birth weight and haematological indexes. The mean values (SD) of haematological indexes were as follows: Hb 8.7 +/- 1.5 g/dl; PCV 30.4 +/- 5.1%; RBC 2.5 +/- 0.6 x 10(2)/l; mean corpuscular haemoglobin concentration (MCHC) 28.9 +/- 4 g/dl; mean corpuscular volume (MCV) 151.5 +/- 120 fl and mean corpuscular haemoglobin (MCH) 35.2 +/- 7.9 pg. The results have shown that 95% of the subjects were anaemic at the time of the study. All subjects were suffering from iron, folate and vitamin B 12 deficiencies. This suggests that all subjects had a combination of microcytic and megaloblastic anaemia. The results have also shown that there was a positive correlation (r = 0.76; P = 0.01) between Hb concentration and weight of the infants at birth. Subjects who had Hb concentration of below 7.4 g/dl delivered infants that were weighing below 2500 g (mean birth weight of 2160 +/- 228 g). For those who had an Hb concentration of above 9.5 g/dl delivered infants weighing more than 3000 g (mean 3142 +/- 329 g). The mean birth weight of the infants born to anaemic subjects (Hb < 7.9 g/dl) was significantly lower compared to that of infants born to non-anaemic subjects. This observation suggests that anaemia had a significant influence on the birth weight of the infant. This could also be an indication of poor food security in general. Major causes of anaemia were identified as being poor dietary intake of iron rich foods and probably poor utilisation due to diseases such as malaria. All women had basic knowledge on anaemia. Most of the information was obtained from maternal and child health clinics (76%), schools (15%) and radio programmes (4%). However, despite their awareness on anaemia, the women were still anaemic. The main reason was lack of economic access to appropriate foods.

Seasonal variation of birth weight distribution in Morogoro, Tanzania.

The data of 19,783 full term singleton babies were examined to determine the effect of seasonal variation on birth weight. The mean birth weight was found to be 3020 +/- 502 g. Out of these births, 2354 (11.9%) babies weighed less than 2500 g. Birth weight and percentage low birth weight showed variation with season. Mean birth weight was low during the rainy season and high during the dry season, a period immediately after harvest. This observation suggests that mean birth weight varies with season, which in turn determines the level of energy expenditure and food availability. The study has also shown that there is a rapid response of birth weight to changing conditions of food intake and energy expenditure rather than a slow rise or fall in birth weight in response to gradual changes of conditions as is generally believed. Additionally, the study has shown that birth weight does not only respond to the conditions prevailing during the last few months of pregnancy, but also to the conditions existing just before delivery. This observation would have significant implications in food supplementation programmes for pregnant women.

PIP: Low birth weight (LBW) has been defined as a birth weight below 2500 g. Birth weight is increasingly being used as an indicator of socioeconomic development, with comparative studies of different ethnic groups under various socioeconomic conditions having found birth weight to be largely affected by the socioeconomic setting and little by ethnic grouping. The occurrence of LBW is a reflection of maternal stress during pregnancy. Maternal nutrition is one of the most important factors influencing pregnancy and the state of the newborn baby. Studies have shown maternal weight gain to be the most important predictor of infant birth weight. In most developing countries, however, the outcome of pregnancy is determined by the availability of food which also determines the level of energy intake and energy expenditure; both are highly dependent upon the rainfall pattern in a given area. This paper reports findings from a study exploring the influence of seasonal variation upon the distribution of birth weight in the town of Morogoro, Tanzania. The author examined data for 19,783 full-term singleton babies to determine the effect of seasonal variation on birth weight. Mean birth weight was found to be 3020 +or- 502 g, and 2354 of the babies were of LBW. Mean birth weight was lowest during the rainy season and highest during the dry season, a period immediately after harvest. Birth weight responded rapidly to changing conditions of food intake and energy expenditure rather than the generally expected slow rise or fall in birth weight in response to gradual changes in conditions. The study also found that birth weight does not only respond to prevailing conditions during the last few months of pregnancy, but also to existing conditions just prior to delivery. This latter finding has significant implications for food supplementation programs for pregnant women.

Thermic effect of food in man: effect of meal composition, and energy content.

The effect of meal composition and energy content on the thermic effect of food (TEF) was investigated in sixteen adult, non-obese female subjects. Each subject consumed four different test meals, each meal on a different day. Meals were of high-carbohydrate-low-fat (HCLF) with 0.70, 0.19 and 0.11 of the energy content from carbohydrate, fat and protein respectively, and low-carbohydrate-high-fat (LCHF) with 0.24, 0.65 and 0.11 of the energy content from carbohydrate, fat and protein respectively. The energy contents of the test meals for each composition were 2520 kJ (600 kcal) and 5040 kJ (1200 kcal). The basal metabolic rate (BMR) and the postprandial metabolic rate (PP-MR) were measured by open-circuit indirect calorimetry using the Douglas bag technique while the subjects were in the supine position. The mean BMR value was 3.63 (SE 0.07) kJ/min (0.87 kcal/min (SE 0.017)). The 5 h-TEF value for the 2520 kJ (600 kcal) HCLF meal was 228 (SE 11.8) kJ (54 kcal (SE 2.8)) and for the LCHF meal was 228 (SE 9.6) kJ (54 kcal (SE 2.3)). The corresponding values for the 5040 kJ (1200 kcal) meals were 356 (SE 20.4) kJ (85 kcal (SE 4.9)) and 340 (SE 15.8) kJ (81 kcal (SE 3.8)). There was no significant (P = 0.49) effect of meal composition on TEF, but the energy content of the meals had a significant (P less than 0.001) effect on TEF. In all subjects and for all meals, PP-MR had not returned to premeal level 5 h after a meal, indicating that the TEF values measured underestimate total TEF. The present study suggests that TEF is significantly influenced by the energy content of a meal but not by meal composition.

Effect of meal frequency on the thermic effect of food in women.

The effect of meal frequency on the thermic effect of food (TEF), also referred to as dietary induced thermogenesis (DIT), was investigated in eighteen non-obese female subjects. Their metabolic rate before and after consuming the test meal was measured by open circuit indirect calorimetry using the Douglas bag technique, while the subjects were in the resting state (lying down). Eight subjects consumed a high carbohydrate-low fat (HCLF) meal providing 70, 19 and 11 per cent of the energy content from carbohydrate, fat and protein, respectively, and ten other subjects consumed a low carbohydrate-high fat (LCHF) meal providing 24, 65 and 11 per cent of the energy from carbohydrate, fat and protein, respectively. On two separate occasions, each subject consumed the appropriate diet either as one large meal containing 5040 kJ (1200 kcal) or as two smaller meals each containing 2520 kJ (600 kcal). TEF values were calculated for 6 h after the test meal and the mean values after consuming the HCLF meal were 377.0 +/- 30.0 kJ (90 +/- 7.2 kcal) and 381.0 +/- 26.5 kJ (91.0 +/- 6.3 kcal) for the one meal and the two meals, respectively. The mean TEF values for the subjects who consumed the LCHF meal wre 356.0 +/- 23.0 kJ (85.0 +/- 5.5 kcal) and 340 +/- 15.9 kJ (81.0 +/- 3.8 kcal) for the one meal and the two meals, respectively. No significant differences were found between the two feeding regimens (HCLF, P = 0.94; LCHF, P = 0.64) as well as between the compositions (P = 0.57). Thus, meal frequency and meal composition did not seem to influence the TEF.