ORCID Profile
0000-0003-4829-0054
Current Organisation
North-West University
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Publisher: Oxford University Press (OUP)
Date: 29-03-2018
Abstract: Light physical activity is known to reduce atrial fibrillation risk, whereas moderate to vigorous physical activity may result in an increased risk. However, the question of what volume of physical activity can be considered beneficial remains poorly understood. The scope of the present work was to examine the relation between physical activity volume and atrial fibrillation risk. A comprehensive systematic review was performed following the PRISMA guidelines. A non-linear meta-regression considering the amount of energy spent in physical activity was carried out. The first derivative of the non-linear relation between physical activity and atrial fibrillation risk was evaluated to determine the volume of physical activity that carried the minimum atrial fibrillation risk. The dose–response analysis of the relation between physical activity and atrial fibrillation risk showed that physical activity at volumes of 5–20 metabolic equivalents per week (MET-h/week) was associated with significant reduction in atrial fibrillation risk (relative risk for 19 MET-h/week = 0.92 (0.87, 0.98). By comparison, physical activity volumes exceeding 20 MET-h/week were unrelated to atrial fibrillation risk (relative risk for 21 MET-h/week = 0.95 (0.88, 1.02). These data show a J-shaped relation between physical activity volume and atrial fibrillation risk. Physical activity at volumes of up to 20 MET-h/week is associated with reduced atrial fibrillation risk, whereas volumes exceeding 20 MET-h/week show no relation with risk.
Publisher: Elsevier BV
Date: 2005
DOI: 10.1016/J.NUT.2004.09.010
Abstract: First, we wanted to dispel the myth that avocados are fattening and therefore should be avoided in energy-restricted diets. Second, we examined the effects of avocados, a rich source of monounsaturated fatty acids, as part of an energy-restricted diet on weight loss, serum lipids, fibrinogen, and vascular function in overweight and obese subjects. Sixty-one free-living volunteers (13 men and 48 women), with body mass index of 32 +/- 3.9 kg/m(2) (mean +/- standard deviation) participated in this randomized, controlled, parallel study. Subjects were paired and randomly assigned to one of two groups. The experimental group consumed 200 g/d of avocado (30.6 g of fat), which substituted for 30 g of other mixed dietary fats such as margarine or oil, and the control group excluded avocado from their energy-restricted diet for 6 wk. Seven-day isoenergetic menus were planned according to mean energy requirements of both sexes to provide total energy intakes consisting of 30% fat, 55% carbohydrates, and 15% protein. Anthropometric measurements, physical activity, blood pressure, and arterial compliance were measured with standard methods at the beginning and end of the intervention. Fasting blood s les were drawn at the beginning and end of the intervention. Fifty-five subjects completed the study. The compliance rate to avocado intake in the experimental group was 94.6%. The percentage of plasma oleic acid increased significantly with the consumption of avocado in the experimental group, whereas a decrease was seen in the percentage of myristic acid from baseline to the end of the intervention in both groups but was significant only in the experimental group. Anthropometric measurements (body mass, body mass index, and percentage of body fat) decreased significantly in both groups during the study (P < 0.001), and the change was similar in both groups. Serum lipid concentrations (total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triacylglycerols), fibrinogen, blood pressure, and arterial compliance did not change significantly within or between groups. The consumption of 200 g/d of avocado within an energy-restricted diet does not compromise weight loss when substituted for 30 g of mixed dietary fat. Serum lipid concentrations, plasma fibrinogen, arterial compliance, and systolic and diastolic blood pressures were not affected by weight loss or avocado intake.
Publisher: Wiley
Date: 12-2008
DOI: 10.1002/AJIM.20635
Publisher: Cambridge University Press (CUP)
Date: 04-07-2013
DOI: 10.1017/S000711451300189X
Abstract: Little is known about the effects of combined micronutrient and sugar consumption on growth and cognition. In the present study, we investigated the effects of micronutrients and sugar, alone and in combination, in a beverage on growth and cognition in schoolchildren. In a 2 × 2 factorial design, children ( n 414, 6–11 years) were randomly allocated to consume beverages containing (1) micronutrients with sugar, (2) micronutrients with a non-nutritive sweetener, (3) no micronutrients with sugar or (4) no micronutrients with a non-nutritive sweetener for 8·5 months. Growth was assessed and cognition was tested using the Kaufman Assessment Battery for Children version II (KABC-II) subtests and the Hopkins Verbal Learning Test (HVLT). Micronutrients decreased the OR for Fe deficiency at the endpoint (OR 0·19 95 % CI 0·07, 0·53). Micronutrients increased KABC Atlantis (intervention effect: 0·76 95 % CI 0·10, 1·42) and HVLT Discrimination Index (1·00 95 % CI 0·01, 2·00) scores. Sugar increased KABC Atlantis (0·71 95 % CI 0·05, 1·37) and Rover (0·72 95 % CI 0·08, 1·35) scores and HVLT Recall 3 (0·94 95 % CI 0·15, 1·72). Significant micronutrient × sugar interaction effects on the Atlantis, Number recall, Rover and Discrimination Index scores indicated that micronutrients and sugar in combination attenuated the beneficial effects of micronutrients or sugar alone. Micronutrients or sugar alone had a lowering effect on weight-for-age z -scores relative to controls (micronutrients − 0·08 95 % CI − 0·15, − 0·01 sugar − 0·07 95 % CI − 0·14, − 0·002), but in combination, this effect was attenuated. The beverages with micronutrients or added sugar alone had a beneficial effect on cognition, which was attenuated when provided in combination.
Publisher: MDPI AG
Date: 25-12-2018
Abstract: Recent studies have highlighted the potential protective role of omega-3 polyunsaturated fatty acids (n-3 PUFA) in asthma. This study aimed at determining the association between seafood intake, serum PUFA composition and clinical endpoints of asthma in adults. A cross-sectional study of 642 subjects used the European Committee Respiratory Health Survey (ECRHS) questionnaire, skin prick tests, spirometry and methacholine challenge tests following ATS guidelines. Sera was analysed for n-3 and n-6 PUFA composition. Subjects had a mean age of 34 years, were largely female (65%) and 51% were current smokers. While 99% reported fish consumption, rock lobster, mussels, squid and abalone were also consumed less frequently. The prevalence of asthma symptoms was 11%, current asthma (ECRHS definition) was 8% and non-specific bronchial hyperresponsiveness (NSBH) was much higher (26%) In adjusted models the n-3 PUFAs 20:5 (EPA) and 22:5 (DPA) were significantly associated with a decreased risk of having NSBH. Total n-3 PUFA composition was associated with decreased NSBH risk (OR = 0.92), while high n-6 PUFA composition was associated with an increased risk (OR = 1.14).
Publisher: MDPI AG
Date: 06-09-2019
DOI: 10.3390/FOODS8090394
Abstract: Nutritional transition in Africa is linked with increased blood pressure (BP). We examined 10-year fatty acid status and longitudinal associations between in idual long-chain polyunsaturated fatty acids (PUFA), BP and status of hypertension (≥140/90 mmHg and/or medication use) in black South Africans. We included 300 adults ( years) participating in the Prospective Urban Rural Epidemiology study, and analysed data from three consecutive examinations (2005, 2010 and 2015 study years). Fatty acids in plasma phospholipids were analysed by gas chromatography-mass spectrometry. We applied sequential linear mixed models for continuous outcomes and generalized mixed models for the hypertension outcome, in the complete s le and separately in urban and rural subjects. Mean baseline systolic/diastolic BP was 137/89 mmHg. Ten-year hypertension status increased among rural (48.6% to 68.6%, p = 0.001) and tended to decrease among urban subjects (67.5% to 61.9%, p = 0.253). Regardless of urbanisation, n-6 PUFA increased and eicosapentaenoic acid (EPA, C20:5 n-3) decreased over the 10-years. Subjects in the highest tertile of arachidonic acid (C20:4 n-6) had 3.81 mmHg lower systolic (95% confidence interval (CI): −7.07, −0.54) and 3.82 mmHg lower diastolic BP (DBP) (95% CI: −5.70, −1.95) compared to the reference tertile, irrespective of lifestyle and clinical confounders. Similarly, osbond acid (C22:5 n-6) was inversely associated with DBP. Over the 10-years, subjects in the highest EPA tertile presented with +2.92 and +1.94 mmHg higher SBP and DBP, respectively, and with 1.46 higher odds of being hypertensive. In black South African adults, in idual plasma n-6 PUFA were inversely associated with BP, whereas EPA was adversely associated with hypertension, supporting implementation of dietary fat quality in national cardiovascular primary prevention strategies.
Publisher: Wiley
Date: 23-10-2009
DOI: 10.1007/S11745-009-3359-6
Abstract: Conjugated linoleic acid (CLA) is a popular supplement believed to enhance immune function, body composition and insulin sensitivity, but results of scientific studies investigating its effects are conflicting. The isomer- and tissue-specific effects of CLA may explain these conflicting results. Therefore, this study quantified the incorporation of the c9t11 and t10c12 CLA isomers into adipose tissue and skeletal muscle in response to supplementation in healthy, regularly-exercising, non-obese persons. The CLA group (n = 14) ingested 3.9 g per day CLA (50:50 t9c11:c10t12) and the placebo group (n = 11) 3.9 g per day high-oleic-acid sunflower oil for 12 weeks. Following supplementation, the t10c12 isomer was incorporated into adipose tissue triacylglycerol (P < 0.001), and the c9t11 isomer tended to increase in skeletal muscle phospholipids (P = 0.056). Therefore, human adipose tissue and skeletal muscle are enriched with CLA in an isomer-specific manner.
No related grants have been discovered for Cornelius Smuts.