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Weight velocity of 34 Egyptian infants aged two to thirteen months was examined before, during, and after 43 diarrheal episodes. The study was conducted in Bolaq El Dakrour, a poor neighborhood in metropolitan Cairo, during the summer of 1990. Weight measurements, food intake, morbidity, and socio-demographic-economic-sanitary data were collected. Diarrhea was reported according to mothers' definitions. A local reference population was constructed based on the criteria that: infants were from the same neighborhood, of the same age and sex, and were reported diarrhea-free when study infants were reported sick. Weight velocity during diarrheal episodes was 16 g/d lower than before illness and 15 g/d lower than reference infants. One-month post-illness weight velocity was similar to pre-illness weight velocity, with no evidence of catch-up growth. Illness severity indices, namely the number of symptoms or illnesses experienced, number of stools/day, and presence of blood in stool were strong predictors of velocity during and one-month post-illness. Breastfeeding had a positive influence on weight velocity during illness. Consumption of rice, macaroni and vegetables was negatively associated with weight velocity during and one month after illness. Weight gain in the month following the episode was positively associated with a higher level of formal education and occupation of fathers, negatively with the presence of adults above 50 years of age in the household, and a greater age difference between the parents. Percent of time sick with fever had a negative impact on long-term weight velocity. Thus in this population, the effect of diarrhea on weight gain velocity is transient, catch-up growth does not occur, and infants fed solid food suffer the most weight loss. Thus, it is possible that effective nutritional intervention will reduce growth faltering.

Factors that influence exclusive breastfeeding in Namibia are important, especially in light of the implementation of the Baby and Mother Friendly Initiative. Infant feeding practices, especially breastfeeding, are important public health issues, particularly in the prevention of HIV transmission from mother to child. This thesis determined the prevalence of exclusive breastfeeding and measures the association of demographic and service-related factors on exclusive and non-exclusive breastfeeding practices.

Docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6) are deposited in large amounts in membrane phospholipids of the developing central nervous system (CNS). High levels of 22:6n-3 are found in synaptic terminals and retina, and are important for normal visual development and function. 20:4n-6 and22:6n-3 are supplied in human milk. In contrast, infants fed formula rely completely on endogenous synthesis of 20:4n-6 and 22:6n-3 from linoleic (18:2n-6) and a-linolenic (18:3n-3) acid, respectively. Levels of 22:6n-3 in the blood lipids of infants fed formula are lower than in infants fed human milk. Concern over the supply of 22:6n-3 led to clinical trials in which premature infants were fed formulas containing fish oils as a source of 22:6n-3. Piglets, which have a similar lipid metabolism and perinatal timing of the brain growth spurt to humans, have a lower percentage of 22:6n-3 in blood, liver and CNS tissues when fed formula with 30% of fatty acids as18:2n-6 and 0.8% 18:3n-3, compared to sow milk. It was hypothesized that the low blood and tissue 22:6n-3 in formula-fed piglets was due to inappropriate quantities and/or ratios of dietary 18:2n-6 and 18:3n-3 limiting the synthesis of 22:6n-3. Thus, the main objectives of this thesis were to determine. (1) if 22:6n-3 is an essential dietary nutrient for the term gestation piglet, (2) if appropriate quantities and ratios of 18:2n-6 and 18:3n-3 in formula will support CNS membrane accretion of 20:4n-6 and 22:6n-3, comparable to piglets fed varying amounts of 22:6n-3 in natural milk, and (3) if lower blood phospholipid 22:6n-3 consistently reflects reduced 22:6n-3 in the CNS. Initial studies (Experiment I) showed that formula with 4% 18:3n-3 supported a similar percentage of22:6n-3 in piglet liver and CNS membrane lipids to sow milk, but was associated with lower brain weight. Deposition of 22:6n-3 in brain was influenced by the formula 18:3n-3 content. The 18:2n-6:18:3n-3 ratio (22:1and 37:1) seemed to be important, however, when formulas contained 1% 18:3n-3. Low levels of fish oil in formula, similar to those used in clinical trials, were effective in supplying 22:6n-3 to the developing piglet brain (Experiment II). The efficacy of 18:3n-3 in supporting the deposition of 22:6n-3 in the brain was estimated to be at least 20% that of dietary 20:5n-3 plus 22:6n-3. With increasing dietary fish oil, however, levels of eicosapentaenoic acid (20:5n-3) increased and 20:4n-6decreased in plasma, liver and retina, but not brain (Experiment III). This suggests regulatory mechanisms may exist to maintain relatively constant levels of 20:4n-6 and 20:5n-3 in brain. Milk 22:6n-3 varies with maternal intake of 22:6n-3. The effect of milk 22:6n-3 content was studied in piglets fed milk with 0.1% or 1.5% 22:6n-3 obtained from sows fed usual pig diets containing vegetable fats without or with fish oil, respectively (Experiment IV). Consumption of 1.5 vs 0.1% 22:6n-3 from sow milk resulted in 300% higher 22:6n-3 in liver and blood phospholipids and 11% higher 22:6n-3 in cerebrum of nursing piglets. Despite similar milk 20:4n-6, the % 20:4n-6 in tissues other than the brain was lower in piglets fed high22:6n-3 sow milk. Thus, high intakes of n-3 fatty acids decrease 20:4n-6 in piglet liver and blood lipids. The blood phospholipid % 22:6n-3 in piglets fed formulas containing 18:2n-6 and 18:3n-3 but not their long-chain derivatives, was lower than in piglets fed 22:6n-3 in natural milk, consistent with published findings in formula-fed infants. However, in contrast to circulating lipids, formulas with 4% 18:3n-3 maintained similar levels of 22:6n-3in the piglet CNS compared to milk. These studies show that blood phospholipid 22:6n-3 and 20:4n-6 are not specific indices of effects in CNS lipids. This thesis has shown (1) 22:6n-3 is not essential in the diet of the term piglet, if adequate 18:3n-3 is given, (2) fish oils are an effective source of 22:6n-3 for deposition in the developing brain, (3) high dietary n-3fatty acids interfere with 20:4n-6 metabolism, and (4) blood lipid 20:4n-6 and 22:6n-3 do not accurately reflect CNS fatty acids.

Factors that influence exclusive breastfeeding in Namibia are important, especially in light of the implementation of the Baby and Mother Friendly Initiative. Infant feeding practices, especially breastfeeding, are important public health issues, particularly in the prevention of HIV transmission from mother to child. This thesis determined the prevalence of exclusive breastfeeding and measures the association of demographic and service-related factors on exclusive and non-exclusive breastfeeding practices.

A controlling maternal feeding style can have negative consequences for child weight and eating style (Ventura & Birch, 2008). Mothers who breastfeed during the first year exert lower levels of control over child feeding (Farrow & Blissett, 2008). Explanations for this relationship speculate that experience of breastfeeding reduces control as breastfeeding requires an infant-led approach (Taveras et al. 2004) or alternatively that maternal attitudes predict both initiation of breastfeeding and later maternal control (Farrow & Blissett, 2006a). The nature of this relationship is explored in this thesis. Mothers reported their intended and actual feeding style during milk feeds when pregnant and at six months postpartum using a modified version of the Child Feeding Questionnaire (Birch, Fisher, Grimm-Thomas, Markey, Sawyer, & Johnson. 2001). Maternal use of control in the form of scheduling and encouraging milk feeds was evident. A high level of control was associated with a shorter breastfeeding duration (p < 0.001). Control beliefs were present prenatally with intended breastfeeding duration inversely associated with intended control. Furthermore, attitudes towards the infant-led nature of breastfeeding were associated with both breastfeeding duration and control. Breastfed infants need to be fed to infant demand and amount consumed is immeasurable whilst formula feeding is open to maternal manipulation. A belief that breastfeeding was inconvenient was associated with scheduling feeds whilst concerns over milk intake and low confidence were associated with encouraging feeds. Whilst scheduling feeds was a stable behaviour predictive from prenatal intention, encouraging feeds was fluid and related to maternal experience. Concerns about infant size or feeding difficulties increased use of encouraging feeds. Maternal desire for control may therefore drive breastfeeding duration, explaining the association between breastfeeding and later feeding style. The findings have important implications for breastfeeding duration, early programming of appetite and bodyweight and later maternal feeding style.

Docosahexaenoic acid (22:6n-3) and arachidonic acid (20:4n-6) are deposited in large amounts in membrane phospholipids of the developing central nervous system (CNS). High levels of 22:6n-3 are found in synaptic terminals and retina, and are important for normal visual development and function. 20:4n-6 and22:6n-3 are supplied in human milk. In contrast, infants fed formula rely completely on endogenous synthesis of 20:4n-6 and 22:6n-3 from linoleic (18:2n-6) and a-linolenic (18:3n-3) acid, respectively. Levels of 22:6n-3 in the blood lipids of infants fed formula are lower than in infants fed human milk. Concern over the supply of 22:6n-3 led to clinical trials in which premature infants were fed formulas containing fish oils as a source of 22:6n-3. Piglets, which have a similar lipid metabolism and perinatal timing of the brain growth spurt to humans, have a lower percentage of 22:6n-3 in blood, liver and CNS tissues when fed formula with 30% of fatty acids as18:2n-6 and 0.8% 18:3n-3, compared to sow milk. It was hypothesized that the low blood and tissue 22:6n-3 in formula-fed piglets was due to inappropriate quantities and/or ratios of dietary 18:2n-6 and 18:3n-3 limiting the synthesis of 22:6n-3. Thus, the main objectives of this thesis were to determine. (1) if 22:6n-3 is an essential dietary nutrient for the term gestation piglet, (2) if appropriate quantities and ratios of 18:2n-6 and 18:3n-3 in formula will support CNS membrane accretion of 20:4n-6 and 22:6n-3, comparable to piglets fed varying amounts of 22:6n-3 in natural milk, and (3) if lower blood phospholipid 22:6n-3 consistently reflects reduced 22:6n-3 in the CNS. Initial studies (Experiment I) showed that formula with 4% 18:3n-3 supported a similar percentage of22:6n-3 in piglet liver and CNS membrane lipids to sow milk, but was associated with lower brain weight. Deposition of 22:6n-3 in brain was influenced by the formula 18:3n-3 content. The 18:2n-6:18:3n-3 ratio (22:1and 37:1) seemed to be important, however, when formulas contained 1% 18:3n-3. Low levels of fish oil in formula, similar to those used in clinical trials, were effective in supplying 22:6n-3 to the developing piglet brain (Experiment II). The efficacy of 18:3n-3 in supporting the deposition of 22:6n-3 in the brain was estimated to be at least 20% that of dietary 20:5n-3 plus 22:6n-3. With increasing dietary fish oil, however, levels of eicosapentaenoic acid (20:5n-3) increased and 20:4n-6decreased in plasma, liver and retina, but not brain (Experiment III). This suggests regulatory mechanisms may exist to maintain relatively constant levels of 20:4n-6 and 20:5n-3 in brain. Milk 22:6n-3 varies with maternal intake of 22:6n-3. The effect of milk 22:6n-3 content was studied in piglets fed milk with 0.1% or 1.5% 22:6n-3 obtained from sows fed usual pig diets containing vegetable fats without or with fish oil, respectively (Experiment IV). Consumption of 1.5 vs 0.1% 22:6n-3 from sow milk resulted in 300% higher 22:6n-3 in liver and blood phospholipids and 11% higher 22:6n-3 in cerebrum of nursing piglets. Despite similar milk 20:4n-6, the % 20:4n-6 in tissues other than the brain was lower in piglets fed high22:6n-3 sow milk. Thus, high intakes of n-3 fatty acids decrease 20:4n-6 in piglet liver and blood lipids. The blood phospholipid % 22:6n-3 in piglets fed formulas containing 18:2n-6 and 18:3n-3 but not their long-chain derivatives, was lower than in piglets fed 22:6n-3 in natural milk, consistent with published findings in formula-fed infants. However, in contrast to circulating lipids, formulas with 4% 18:3n-3 maintained similar levels of 22:6n-3in the piglet CNS compared to milk. These studies show that blood phospholipid 22:6n-3 and 20:4n-6 are not specific indices of effects in CNS lipids. This thesis has shown (1) 22:6n-3 is not essential in the diet of the term piglet, if adequate 18:3n-3 is given, (2) fish oils are an effective source of 22:6n-3 for deposition in the developing brain, (3) high dietary n-3fatty acids interfere with 20:4n-6 metabolism, and (4) blood lipid 20:4n-6 and 22:6n-3 do not accurately reflect CNS fatty acids. / Land and Food Systems, Faculty of / Graduate

In early Infancy, limited ingestion of vitamin E, especially the α-tocopherol form, and/or a high, intake of polyunsaturated fatty acids are reflected as a low serum tocopherol level. This vitamin E deficiency state is probably responsible for the development of an anemia characterized by abnormal erythrocyte hemolysis. Edema and skin changes may also be present. In order to ascertain the tocopherol status of infant formulas available in Canada, thirty-six representative formulas were chemically analyzed for vitamin E and polyunsaturated fatty acid contents. For the tocopherol analysis, a combination of the Emmerie-Engel procedure and two-dimensional thin-layer chromatography was used. An alkaline isomerization technique was chosen for the polyunsaturated fatty acid analysis. The vitamin E status of the various formulas was assessed in relation to three criteria of tocopherol adequacy - the α-tocopherol-to-PUFA ratio, the α-tocopherol content, and the level of International Units of vitamin E. With the exception of one formula which was supplemented with vitamin E, the twenty-one formulas based on fresh or modified cow's milk often contained insufficient tocopherol to meet the various criteria of adequacy. A large per cent of the vitamin E content in these formulas was present as α-tocopherol. The polyunsaturated fatty acid content was relatively low. In general, the fifteen proprietary formulas had much higher levels of vitamin E and polyunsaturated fatty acids than the formulas based on fresh or modified cow's milk. For many of the proprietary products, α-tocopherol constituted only a small part of the vitamin E content. Four of the proprietary formulas (including three which had been fortified with vitamin E) contained sufficient amounts of vitamin E to satisfy the three standards of adequacy. On the basis of the chemical analysis results, it is recommended that all infant formulas be supplemented with sufficient amounts of vitamin E. to meet the various criteria of adequacy. In this way, the risk of vitamin E deficiency in early childhood should be minimal. The present study is also concerned with past, present, and future trends in infant feeding practices. In the 1960's, the ready-to-feed hospital feeding systems, which are usually based on a proprietary preparation,were introduced in Canada. A survey conducted among Canadian hospitals indicated that the use of such systems has become widespread. At the same time, the popularity of the hospital-prepared formula system has declined. Consequently, the use of modified cow's milk formulas has declined in Canadian hospitals. However, such formulas are frequently used for home-feeding of infants. No definite trends were noted in the frequency of breast-feeding. / Land and Food Systems, Faculty of / Graduate

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