Frederick J. Veldman

Consumer acceptance of yellow, provitamin A-biofortified maize in KwaZulu-Natal

Abstract Objectives: To assess the acceptance of popular maize food products (phutu, thin porridge and samp), prepared with yellow, provitamin A-biofortified maize varieties, in 212 subjects between the ages of three and 55 years, from rural KwaZulu-Natal. Design: A cross-sectional study. Method: Preschool, primary school and secondary school subjects were randomly selected from two primary schools and one secondary school, respectively, while adult subjects constituted a convenience sample. Pre- and primary school children completed a paired preference test. Secondary school and adult subjects completed a five-point facial hedonic and a preference ranking test. Focus group discussions were conducted using adult subjects. Results: Preschool children preferred yellow maize to white maize food products: phutu (81% vs. 19%; p-value < 0.001), thin porridge (75% vs. 25%; p-value < 0.001) and samp (73% vs. 27%; p-value < 0.001). There was no statistically significant difference in preference for white and yellow maize by primary school children. Secondary school and adult subjects preferred white maize to yellow maize. Focus group discussions confirmed the preference for white maize by the adults. Conclusion: The study findings suggest that yellow, provitamin A-biofortified maize has the potential to succeed as a new strategy of dealing with the serious problem of vitamin A deficiency, especially among children of preschool age. However, in older groups, this strategy is unlikely to be successful, unless other strategies are implemented, including intensive nutrition education programmes on the nutritional benefits of the maize, targeting the market price at which yellow maize is sold, increasing its availability in local grocery stores, and improving its sensory properties through breeding.

Diet and haemostasis: time for nutrition science to get more involved.

Abnormal haemostasis, and specifically a pre-thrombotic state characterized by hypercoagulability, increased platelet aggregation and impaired fibrinolysis, is associated with increased atheroma and thrombosis. The recent literature clearly indicates that diet may prevent or be used to treat some abnormal haemostatic states. There are reports on effects of energy intake and expenditure, alcohol consumption, intakes of total fat, different fatty acids, fish oil, NSP and vitamins on markers of coagulation, platelet function and fibrinolysis. Some of the confusion and controversy in this field has arisen because the wrong markers of haemostasis have been measured in dietary trials. Moreover, many of the studies have lacked good dietary control. It is suggested that more sensitive, functional markers of the balance between the different facets of the haemostatic system should be measured. It is also important to test hypotheses developed from known observations and to propose mechanisms of action of the various dietary factors, based on our improved understanding of the haemostatic system.

Provitamin A carotenoids in biofortified maize and their retention during processing and preparation of South African maize foods

Provitamin A-biofortified maize may contribute to alleviating vitamin A deficiency (VAD), in developing countries. However, processing the maize into food products may reduce its provitamin A content. The aims of this study were to determine the composition of provitamin A carotenoids in biofortified maize varieties as well as to assess their retention during processing of popular maize foods consumed in KwaZulu-Natal, South Africa. The non-provitamin A carotenoid, zeaxanthin and the provitamin A carotenoids, β-cryptoxanthin, and trans and cis isomers of β-carotene, and other unidentified trans and cis isomers of β-carotene were detected in varying concentrations in the maize. Milling provitamin A-biofortified maize into mealie meal resulted in a higher retention of carotenoids compared to milling into samp. The highest retention of provitamin A carotenoids was observed in cooked phutu and cooked samp, whilst cooking into thin porridge resulted in the lowest retention of provitamin A carotenoids. In phutu, 96.6 ± 20.3% β-cryptoxanthin and 95.5 ± 13.6% of the β-carotene were retained after cooking. In samp, 91.9 ± 12.0% β-cryptoxanthin and 100.1 ± 8.8% β-carotene; and in thin porridge, 65.8 ± 4.6% β-cryptoxanthin and 74.7 ± 3.0% β-carotene were retained after cooking. This study demonstrates that provitamin A retention in maize is affected by the cooking method (and hence cooked food form) and therefore cooking methods that result in a good retention of provitamin A need to be identified and recommended.

Possible Mechanisms through Which Dietary Pectin Influences Fibrin Network Architecture in Hypercholesterolaemic Subjects

Abstract It is suspected that not only fibrinogen concentration but also the quality of fibrin networks may contribute to cardiovascular risk. Evidence is accumulating that a “prudent” diet may protect against diseases associated with raised clotting factors. The effect of diet on fibrinogen is, however, still controversial. In a previous study performed in our laboratory, it was shown that dietary pectin influences fibrin network architecture in hypercholesterolaemic men without causing any changes in fibrinogen concentration. To elucidate the possible mechanisms, it was necessary to study the possibility that pectin may itself have indirect effects on fibrin network architecture. Pectin is fermented in the gastrointestinal tract to acetate, propionate, and butyrate. In humans, only acetate reaches the circulation beyond the liver. This investigation primarily examined the possibility that pectin may, through acetate, influence fibrin network architecture in vivo. The effects of pectin and acetate supplementation in hypercholesterolaemic subjects were compared. Furthermore, this study also aimed at describing the possible in vitro effects of acetate on fibrin network architecture. Two groups of 10 male hyperlipidaemic volunteers each received a pectin (15 g/day) or acetate (6.8 g/day) supplement for 4 weeks. Acetate supplementation did not cause a significant change in plasma fibrinogen levels. As in the pectin group, significant differences were found in the characteristics of fibrin networks developed in plasma after 4 weeks of acetate supplementation. Fibrin networks were more permeable (from 213±76 to 307±81×10 11 cm 2 ), had lower tensile strength (from 23±3 to 32± 9% compaction), and were more lyseable (from 252±11 to 130±15 minutes). These results strongly suggest that the effect of pectin on network architecture could partially be mediated by acetate. Progressive amounts of acetate were used in vitro to investigate the possibility that acetate may be directly responsible for changes that occurred in fibrin network architecture in the plasma medium. Results indicated that acetate influenced fibrin network architecture directly. From the results, it seems highly possible that acetate may be responsible in part for the beneficial effects of pectin supplementation in vivo. It is evident that pectin or acetate supplementation can be useful during the treatment or prevention of some clinical manifestations, especially those associated with raised total cholesterol and possibly also plasma fibrinogen.

Lecithin has no effect on serum lipoprotein, plasma fibrinogen and macro molecular protein complex levels in hyperlipidaemic men in a double-blind controlled study

Objective: To examine the effects of lecithin on serum lipoprotein, plasma fibrinogen and macro molecular protein complex (MPC) levels.Subjects and study design: Twenty free living hyperlipidaemic men participated in this double-blind study which controlled for possible indirect effects. The subjects were randomly assigned to one of three treatments: frozen yoghurt or frozen yoghurt with 20 g soya bean lecithin or frozen yoghurt with 17 g sunflower oil. Sunflower oil was used to control for the increased energy and linoleic acid intake from lecithin. Yoghurt served as the ‘vehicle’ for the lecithin and sunflower oil and yoghurt alone was given to one group to control for possible effects due to the yoghurt ‘vehicle’, as well as other environmental influences. Variables were measured with standard methods twice at baseline and after 2 and 4 weeks of treatment.Results: Plasma linoleic acid levels increased significantly with lecithin and sunflower oil treatments indicating that compliance to the treatments were obtained. Lecithin treatment did not have significant effects on serum total cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol, apolipoprotein A, apolipoprotein B or lipoprotein (a) levels. Plasma fibrinogen and MPC levels were also not affected by lecithin therapy. Sunflower oil treatment resulted in significant increased body weight, serum TC and decreased MPC levels.Conclusion: Lecithin treatment had no independent effects on serum lipoprotein, plasma fibrinogen or MPC levels in hyperlipidaemic men.Sponsorship: Drybean Producers Organisation (South Africa); Chempure cc (South Africa); SACCA, Pty. Ltd. (South Africa).

The metabolic profiles of HIV-infected and non-infected women in Mangaung, South Africa

Abstract Objective: To determine the biochemical nutritional status of HIV-infected women in Mangaung. Design: Cross-sectional. Setting: The community of Mangaung, Free State, South Africa. Subjects: A representative group of 500 black women (25–44 years) was selected randomly to participate. Outcome measures: Biochemical analyses were performed for total lymphocytes, serum protein, serum albumin, plasma fibrinogen, serum insulin, serum glucose, serum triglycerides and serum cholesterol using standard methodology. Values were compared to standard references, and between HIV-infected and HIV-uninfected women. Results: After screening for eligibility, 488 women qualified. Sixty-one per cent of the younger women (25–34 years) and 38% of the older women (35–44 years) were HIV-infected. HIV-infected women had significantly lower median blood values for total lymphocytes (p = 0.0001 and p = 0.02 for younger and older group respectively) and serum albumin (p = 0.0001 for both age groups), but significantly higher median concentrations of serum protein (p = 0.0001 for both age groups) than uninfected women. Plasma fibrinogen and serum insulin concentrations were significantly lower in HIV-infected younger women than in their uninfected counterparts (p = 0.002 for both parameters). Older HIV-infected women had significantly lower total serum cholesterol values (p = 0.01) than older HIV-uninfected women. Serum glucose and serum triglycerides did not differ significantly between HIV-infected and HIV-uninfected women. Conclusions: The results indicate a possible impact of HIV infection on serum protein and serum albumin, which may adversely affect biochemical nutritional status and the course of HIV progression. Future research into the causes and possible treatment of metabolic changes in women in this community should be prioritised.

Venom of a six-eyed crab spider, Sicarius testaceus (Purcell, 1908), causes necrotic and haemorrhagic lesions in the rabbit

By employing haematological, histological and isotope studies on rabbit, it was shown that envenomation by the South African crab spider, Sicarius testaceus, results in tissue necrosis and a marked increase in the permeability of the blood vessels in the vicinity of envenomation. The venom also acts systemically, which results in petechial bleeding of some viscera, thrombocytopaenia and elevated fibrinogen levels. Rabbit envenomation by this species results in a dramatic drop of the platelet count, without haemolytic anaemia. Should these parameters be the same in humans, they may serve as a yardstick to distinguish presumptive S. testaceus envenomation from that of Loxosceles.

The variety, popularity and nutritional quality of tuck shop items available for sale to primary school learners in Pietermaritzburg, South Africa

Abstract Objectives: To determine the variety, popularity and nutritional quality of the food and beverages sold to primary school pupils. Method: A cross-sectional tuck shop survey. Nutritional analyses were conducted using the South African Medical Research Council Foodfinder 3 for Windows® software. Eleven mixed-race, well-resourced, government primary schools were studied in Pietermaritzburg, South Africa. Subjects included tuck shop managers from each school. Results: Savoury pies were the most popular lunch item for all learners for both breaks (n = 5, 45%, and n = 3, 27.3%), selling the most number of units (43) per day at eight schools (72.7%). Iced popsicles were sold at almost every school, ranked as the cheapest beverage, and also sold the most number of units (40.7). Healthy beverages sold included canned fruit juice and water, while healthy snacks consisted of dried fruit, fruit salad, bananas, yoghurt and health muffins. The average healthy snack contained almost half the kilojoules of the unhealthy counterpart (465kJ vs. 806kJ). Nutritional analyses of the healthy lunch options revealed total fat contents that exceeded the Dietary Reference Intake and South African recommended limits. Perceived barriers to stocking healthy items included cost and refrigeration restrictions. Conclusion: School tucks shops are selling products that encourage an unhealthy lifestyle, thereby promoting the obesity epidemic. Extensive consultation is required among dietitians, school principals and privatised tuck shop managers to overcome barriers to stocking healthy food in tuck shops.

Nutritional, immune, micronutrient and health status of HIV-infected children in care centres in Mangaung

Abstract Aim: To assess the nutritional, immune, micronutrient and health status of antiretroviral-naïve HIV-infected children. Method: A cross-sectional descriptive study was undertaken between September 2004 and March 2006 amongst HIV-infected children of which none received antiretroviral therapy, in care centres in Mangaung, Free State. Results: The study included 37 clinically stable and food-secure HIV-infected children. Their median age was 5.4 years (range 1.2–10.2 years). Fifteen children (41%) were underweight, 30 (81%) were stunted and one (3%) was wasted. The most commonly observed clinical features were lymphadenopathy (84%), skin rashes (51%), hepatomegaly (32%) and pallor (41%). Eight per cent of children had features of TB, while 19% had a lower respiratory tract infection. The median viral load of the group (n = 35) was 117 000 copies/ml, the median CD4+ cell count was 477 cells/mm3 and the median CD4 percentage was 22.5%. A significant negative correlation could be demonstrated between viral load and nutritional indicators. Children had deficient serum levels relative to normal reference values for glutathione (91% of children), albumin (78%), vitamin A (63%), vitamin D (44%), zinc (38%) and vitamin E (13%). Sixty per cent of the children were anaemic and 30% were iron deficient. Conclusion: A high prevalence of acute and chronic malnutrition and micronutrient deficiencies occurred among HIV-infected children residing in care centres. The study highlights the need to investigate early initiation of antiretroviral therapy and nutrition interventions, including aggressive supplementation, in order to improve the prognosis of these children.

Cry, the beloved bottle: infant-feeding knowledge and the practices of mothers and caregivers in an urban township outside Bloemfontein, Free State province

Abstract Objectives: To investigate knowledge of and practices regarding bottle-feeding preparation, as well as the nutrient content and microbial safety of bottles that are prepared by mothers and caregivers for infants aged 0-24 months. Design: Cross-sectional descriptive survey. Setting: Urban township, Mangaung, outside Bloemfontein. Subjects: A sample of 189 mothers or caregivers of healthy infants aged 0-24 months, who were exclusively formula fed or mixed fed with breast milk and infant formula or cow’s milk, were randomly selected in a household survey. Outcome measures: An interviewer-administered questionnaire and/or observed practices were used for data collection. Bottle-feed samples were also collected and analysed for nutrient and microbial content. Results: Mother and caregiver knowledge on infant feeding was poor. An acceptable method for preparing a bottle feed in five steps was evaluated. Only 4.2% of the total sample applied all five steps. A total of 84.5% (n = 160) of all the collected feeds was contaminated with E coli. A lower level of maternal education was associated with a greater likelihood of feed contamination. The predominant source of bottle-feeding preparation information was clinic staff (28%). Conclusion: The findings were indicative of a lack of knowledge, and possibly resource limitations, to facilitate safe bottle-feeding practices. Acknowledgement of clinic staff as a source of infant-feeding information highlights the role of healthcare workers as facilitators of appropriate infant-feeding practices.