Alison McAfee

Red meat consumption: an overview of the risks and benefits.

Red meat is long established as an important dietary source of protein and essential nutrients including iron, zinc and vitamin B12, yet recent reports that its consumption may increase the risk of cardiovascular disease (CVD) and colon cancer have led to a negative perception of the role of red meat in health. The aim of this paper is to review existing literature for both the risks and benefits of red meat consumption, focusing on case-control and prospective studies. Despite many studies reporting an association between red meat and the risk of CVD and colon cancer, several methodological limitations and inconsistencies were identified which may impact on the validity of their findings. Overall, there is no strong evidence to support the recent conclusion from the World Cancer Research Fund (WCRF) report that red meat has a convincing role to play in colon cancer. A substantial amount of evidence supports the role of lean red meat as a positive moderator of lipid profiles with recent studies identifying it as a dietary source of the anti-inflammatory long chain (LC) n-3 PUFAs and conjugated linoleic acid (CLA). In conclusion, moderate consumption of lean red meat as part of a balanced diet is unlikely to increase risk for CVD or colon cancer, but may positively influence nutrient intakes and fatty acid profiles, thereby impacting positively on long-term health.

Red meat from animals offered a grass diet increases plasma and platelet n-3 PUFA in healthy consumers.

Red meat from grass-fed animals, compared with concentrate-fed animals, contains increased concentrations of long-chain (LC) n-3 PUFA. However, the effects of red meat consumption from grass-fed animals on consumer blood concentrations of LC n-3 PUFA are unknown. The aim of the present study was to compare the effects on plasma and platelet LC n-3 PUFA status of consuming red meat produced from either grass-fed animals or concentrate-fed animals. A randomised, double-blinded, dietary intervention study was carried out for 4 weeks on healthy subjects who replaced their habitual red meat intake with three portions per week of red meat (beef and lamb) from animals offered a finishing diet of either grass or concentrate (n 20 consumers). Plasma and platelet fatty acid composition, dietary intake, blood pressure, and serum lipids and lipoproteins were analysed at baseline and post-intervention. Dietary intakes of total n-3 PUFA, as well as plasma and platelet concentrations of LC n-3 PUFA, were significantly higher in those subjects who consumed red meat from grass-fed animals compared with those who consumed red meat from concentrate-fed animals (P < 0·05). No significant differences in concentrations of serum cholesterol, TAG or blood pressure were observed between groups. Consuming red meat from grass-fed animals compared with concentrate-fed animals as part of the habitual diet can significantly increase consumer plasma and platelet LC n-3 PUFA status. As a result, red meat from grass-fed animals may contribute to dietary intakes of LC n-3 PUFA in populations where red meat is habitually consumed.

Associations of Prenatal Mercury Exposure From Maternal Fish Consumption and Polyunsaturated Fatty Acids With Child Neurodevelopment: A Prospective Cohort Study in Italy

Background Mercury is a neurotoxin, and limited prenatal exposure to it can affect long-term child neurodevelopment. However, results of epidemiologic studies of such exposure have been inconsistent. We examined the association of prenatal mercury exposure from maternal fish consumption with child neurodevelopment in northern Italy. Methods A population-based cohort of 606 children and their mothers was studied from pregnancy to age 18 months. Mercury levels were measured in maternal hair and blood during pregnancy and in umbilical cord blood and breast milk. Levels of polyunsaturated fatty acids (PUFAs) were measured in maternal serum. Maternal and child intakes of fish were assessed by using a food frequency questionnaire. The Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) was used to evaluate child neurodevelopment. Multivariate linear regression was used to examine the association of mercury exposure with BSID-III scores, after controlling for maternal fish intake, PUFAs during pregnancy, and several other confounders. Results Mean weekly fish intake during pregnancy was less than 2 servings. Mercury concentrations in biological samples were low (mean, 1061 ng/g in hair) and moderately correlated with fish intake, particularly of carnivorous species. Maternal ω-3 PUFA concentrations were poorly correlated with fish intake. Maternal intelligence quotient (IQ) and child intake of fish were significantly associated with neurodevelopment scores. In multivariate models, the level of Hg exposure was not associated with neurodevelopmental performance at 18 months. Conclusions In this Italian population, neurodevelopment at 18 months was associated with child intake of fresh fish and maternal IQ rather than with mercury exposure. The expected beneficial effect of maternal fish intake (from maternal ω-3 PUFAs) was not found.

Choline status and neurodevelopmental outcomes at 5 years of age in the Seychelles Child Development Nutrition Study

Choline is an essential nutrient that is found in many food sources and plays a critical role in the development of the central nervous system. Animal studies have shown that choline status pre- and postnatally can have long-lasting effects on attention and memory; however, effects in human subjects have not been well studied. The aim of the present study was to examine the association between plasma concentrations of free choline and its related metabolites in children and their neurodevelopment in the Seychelles Child Development Nutrition Study, an ongoing longitudinal study assessing the development of children born to mothers with high fish consumption during pregnancy. Plasma concentrations of free choline, betaine, dimethylglycine (DMG), methionine and homocysteine and specific measures of neurodevelopment were measured in 210 children aged 5 years. The childrens plasma free choline concentration (9·17 (sd 2·09) μmol/l) was moderately, but significantly, correlated with betaine (r 0·24; P= 0·0006), DMG (r 0·15; P= 0·03), methionine (r 0·24; P= 0·0005) and homocysteine (r 0·19; P= 0·006) concentrations. Adjusted multiple linear regression revealed that betaine concentrations were positively associated with Preschool Language Scale – total language scores (β = 0·066; P= 0·04), but no other associations were evident. We found no indication that free choline concentration or its metabolites, within the normal physiological range, are associated with neurodevelopmental outcomes in children at 5 years of age. As there is considerable animal evidence suggesting that choline status during development is associated with cognitive outcome, the issue deserves further study in other cohorts.

Prenatal exposure to dental amalgam in the Seychelles Child Development Nutrition Study: associations with neurodevelopmental outcomes at 9 and 30 months.

BACKGROUND Dental amalgam is approximately 50% metallic mercury and releases mercury vapor into the oral cavity, where it is inhaled and absorbed. Maternal amalgams expose the developing fetus to mercury vapor. Mercury vapor can be toxic, but uncertainty remains whether prenatal amalgam exposure is associated with neurodevelopmental consequences in offspring. OBJECTIVE To determine if prenatal mercury vapor exposure from maternal dental amalgam is associated with adverse effects to cognition and development in children. METHODS We prospectively determined dental amalgam status in a cohort of 300 pregnant women recruited in 2001 in the Republic of Seychelles to study the risks and benefits of fish consumption. The primary exposure measure was maternal amalgam surfaces present during gestation. Maternal occlusal points were a secondary measure. Outcomes were the childs mental (MDI) and psychomotor (PDI) developmental indices of the Bayley Scales of Infant Development-II (BSID-II) administered at 9 and 30 months. Complete exposure, outcome, and covariate data were available on a subset of 242 mother-child pairs. RESULTS The number of amalgam surfaces was not significantly (p>0.05) associated with either PDI or MDI scores. Similarly, secondary analysis with occlusal points showed no effect on the PDI or MDI scores for boys and girls combined. However, secondary analysis of the 9-month MDI was suggestive of an adverse association present only in girls. CONCLUSION We found no evidence of an association between our primary exposure metric, amalgam surfaces, and neurodevelopmental endpoints. Secondary analyses using occlusal points supported these findings, but suggested the possibility of an adverse association with the MDI for girls at 9 months. Given the continued widespread use of dental amalgam, we believe additional prospective studies to clarify this issue are a priority.

Intakes and adequacy of potentially important nutrients for cognitive development among 5-year-old children in the Seychelles Child Development and Nutrition Study

OBJECTIVE To assess the nutritional adequacy of Seychellois children in relation to nutrients reported to be important for cognitive development. DESIGN Dietary intakes were assessed by 4 d weighed food diaries and analysed using dietary analysis software (WISP version 3·0; Tinuviel Software, UK). Individual nutrient intakes were adjusted to usual intakes and, in order to investigate adequacy, were compared with the UK Estimated Average Requirements for children aged 4-6 years. SETTING Children 5 years old were followed up as part of the Seychelles Child Development Nutrition Study (SCDNS), located in the high-fish-consuming population of Mahé, Republic of Seychelles. SUBJECTS Analysis was carried out on a sample of 229 children (118 boys, 111 girls). RESULTS Children consumed a diet of which fortified cereal and milk products contributed the most to nutrient intakes. The majority (≥80 %) of children met requirements for several nutrients important for child development including Fe, folate and Se. Adjusted dietary intakes of Cu, Zn, iodine, niacin and vitamin A were below the Estimated Average Requirement or Recommended Nutrient Intake. Mean adjusted energy intakes (boys 4769 kJ/d (1139·84 kcal/d), girls 4759 kJ/d (1137·43 kcal/d)) were lower than the estimated energy requirement (boys 5104 kJ/d (1220 kcal/d), girls 5042 kJ/d (1205 kcal/d)) for 88 % of boys and 86 % of girls. CONCLUSIONS Nutrition was adequate for most children within the SCDNS cohort. Low intakes of some nutrients (including Zn, niacin and vitamin A) could reflect nutritional database inaccuracies, but may require further investigation. The study provides valuable information on the adequacy of intakes of nutrients which could affect the growth and development of Seychellois children.

Red meat from animals offered a grass diet increases platelet n-3 PUFA in healthy consumers

Red meat produced from grass-fed animals, compared with that produced from concentrate-fed animals, contains increased concentrations of long chain (LC) n‐3 polyunsaturated fatty acids (PUFA) ( 1,2 ) . The LC n‐3 PUFA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are recommended in dietary quantities of ‡450mg/d for the prevention of cardiovascular disease (CVD) ( 3 ) . The aim of this study was to compare the effects of consuming red meat produced from either grass-fed animals, or concentrate-fed animals on platelet LC n‐3 PUFA status. A randomised, double-blind, dietary intervention study was carried out for 4 weeks on two groups of healthy male and female subjects, who replaced their habitual red meat intake with three portions per week of red meat produced from animals offered a finishing diet of either grass (n = 18 consumers) or concentrate (n = 20 consumers). Meat was sourced from beef cattle (n = 8) and lambs (n = 44) offered a finishing diet of strictly grass or concentrate for a period of 6 weeks prior to slaughter. The weekly meat portions for consumers included one sirloin steak (200 g), one portion of mince beef (250 g) and four lamb medallions (240 g). Dietary intake, blood pressure, platelet fatty acid composition and serum lipids and lipoproteins were analysed at baseline and post-intervention. Consumer platelet concentrations of EPA, docosapentaenoic acid (DPA), DHA and total LC n‐3 PUFA were significantly higher in those subjects who consumed red meat from grass-fed animals compared to those who consumed red meat from concentrate-fed animals (P <0.05). No significant differences in concentrations of serum cholesterol, triacylglycerols (TAG) or blood pressure were observed between groups. The consumption of red meat, in amounts below the weekly limit recommended by the World Cancer Research Fund ( 4 ) , from grass-fed animals compared to concentrate-fed animals significantly increased consumer platelet LC n‐3 PUFA status. Therefore, red meat from grass-fed animals may contribute appreciable amounts of dietary LC n‐3 PUFA in populations where red meat is habitually consumed, which in turn would be beneficial for human health. Further research is needed about on-farm conditions to optimise grass-fed meat on a financially feasible commercial basis.

Plasma total cysteine is a determinant of adiposity in healthy adolescents living in the Republic of Seychelles

A. J. McAfee, M. S. Mulhern, P. M. Ueland, E. M. McSorley, J. M. W. Wallace, G. E. Watson, G. E. Myers, E. van Wijngaarden, C. Shamlaye, P. W. Davidson and J. J. Strain Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, BT52 1SA, UK, Section for Pharmacology, Institute of Medicine, University of Bergen, Bergen, Norway, University of Rochester, School of Medicine and Dentistry, NY, USA and Ministry of Health, Victoria, Mahe, Republic of Seychelles

Plasma phospholipid fatty acid status of 5-year-old children in the Seychelles Child Development Nutrition Study

A. J. McAfee, M. S. Barnes, J. J. Strain, P. W. Davidson, M. P. Bonham, E. M. McSorley, S. W. Thurston, J. M. W. Wallace, C. F. Shamlaye, G. Watson, G. J. Myers and T. W. Clarkson Northern Ireland Centre for Food and Health, University of Ulster, Coleraine, BT52 1SA, UK, School of Medicine and Dentistry, University of Rochester, USA, Ministry of Health, Seychelles and Cornell University, USA and The Johns Hopkins Bloomberg School of Public Health, USA