Meta-Analysis of Omega N-3 Supplements - Literature review Example

Evidence Based Practice Literature Review Strategy Association between methylmercury exposure from omega n-3 supplements fish consumption in prenatal / fetus and child development. Contents Page Evidence Based Practice 1 1 Literature Review Strategy 1 Association between methylmercury exposure from omega n-3 supplements / fish consumption in prenatal / fetus and child development. 1 Meta-Analysis of omega n-3 supplements/fish consumption and methylmercury exposure in prenatal mothers/fetus and child development. 4 References 12 Appendix A 15 Search term keywords used 15 Abstract Studies regarding the recommended intake of fish or omega n-3 fatty acids have provided conflicting recommendations based upon the condition of the individual. While most people are recommended to eat anywhere between 1 and 4 fish meals per week, pregnant or lactating mothers are recommended to take only half that amount if they desire a healthy pregnancy and infant. This prompts the question why is it recommended that children from birth to teenage years, while they’re still developing, eat twice the amount of fish recommended for the prenatal fetus and infant? A careful review of the available literature exposes some of the difficulties discovered in finding an answer to this question. Meta-Analysis of omega n-3 supplements/fish consumption and methylmercury exposure in prenatal mothers/fetus and child development. Intake of omega n-3 (VLCn3 PUFAs) could be associated to construction and functional development of cognitive, sensory, perceptual, and motor neural systems. Docosahexaenoic acid (DHA), an omega n-3, is crucial for the growth and functional development of the brain in infants. DHA is also required for preservation of the normal brain function in adults. The addition of rich DHA in the diet can improve the individual’s learning capability, while insufficient DHA is linked with insufficiency in learning. DHA is drawn into the brain in preference to other fatty acids and the speed at which DHA is assimilated in the brain is exceptionally fast, therefore requiring constant replenishment. In addition, the visual perception of healthy, full-term, formula-fed infants is amplified when their formula contains DHA. Throughout the last 50 years, infants have been given formula diets that are deficient in DHA and other omega-3 fatty acids. DHA deficiencies are associated with foetal alcohol syndrome, attention deficit hyperactivity disorder, cystic fibrosis, phenylketonuria, unipolar depression, aggressive hostility, and adrenoleukodystrophy. Low levels of DHA in the brain are connected with cognitive decline during aging and with onset of sporadic Alzheimer disease (Martinez 1996). Reports have been generated over the last few years, regarding supplements of omega n-3 fish oil, and the effects that it may have on children of school age to improve their behaviour, mental capacity and studying performance amid concerns of poor diet amongst the younger generation (Poulter, 2006). This subject has evoked a lot of interest in the media from ministers to health care professionals, parents and school authorities (Poulter 2006). The vast amount of research by the scientific community is still argumentative as to whether chemical pollution has any long lasting effects on the development in health as it relates to the supplementation of omega n-3 fish oil (Claudio et al, 2000). The developing brain is exceptionally susceptible to permanent damage by exposure to ecological and environmental substances at some stage of development, which leads to vulnerability. Such chemicals as mercury, lead, and polychlorinated biphenyls (PCBs) have been comprehensively studied and understanding is developing of their impairment of cognitive development at certain levels of exposure, presently experienced by a considerable section of the general populace (Stein et al, 2002). The object of this systematic review will look into the safety aspects of giving developing brains of young children omega n-3 fish (very long chained omega n-3 polyunsaturated fatty acids (VLCn3 PUFAs)) oil as a supplement to their diets, or the consumption of fish in the course of trepidation of chemical pollution. It will also discuss the susceptibility and genetic predisposition from parent to foetus during the developmental stage of pregnancy and the effects of exposure from methylmercury. Intended Audience The audience for this review is aimed at those individuals within the health care community, particularly complementary practitioners (GP’s, Nurses), whose responsibilities include providing advice concerning immediate health care, nutrition and medication. The reason for this is because these individuals are generally accepted as the first port of call when the general public is made aware, through such outlets as the general media or governmental publications, of new health recommendations. Because much of this type of information conduit is incomplete and does not provide for audience interaction, the general public must be able to find complete information elsewhere as well as a means of getting case-specific questions answered, which is typically the GP or nurse. In addition, it is often the GP or the nurse who first informs a woman of her pregnancy and the best means of ensuring a healthy baby through proper care and nutrition. It is important, therefore, for the GP and nurse to understand completely the various aspects of omega n-3 supplementation or an increase of fish in a pregnant woman’s diet. By understanding the benefits as well as the risks, the GP and the nurse has a greater ability to appropriately advise pregnant patients regarding these specific health issues. This understanding also assists in the proper care and treatment of young children, including the development of appropriate diet and the identification of any specific defects, deficits or dangers that might be presented through omega n-3 supplementation or environmental pollution. Types of Evidence To provide the best possible evidence for the benefits and risk factors of increased natural consumption of omega n-3 fish oils or the addition of chemically or naturally produced supplements to diet, this study will concentrate on examining available literature from a variety of field studies and researches. This type of evidence provides real-world scenarios as well as lab-tested and controlled studies that will give the target audience an idea not only of the various debates currently held, but also provide them with a solid base of information from which they can conduct their own further research. Particularly relevant to the investigation are studies that have been conducted in the Faroe Islands as well as the Seychelles Child Development study. As a supplement to this information, attention will be given to the various other potential risks to children’s health including possible environmental exposure or exposure through vaccine or dental amalgams. This will done as an effort to fully examine whether the findings in the studies regarding omega n-3 fish oil presents a greater or lesser risk than other living conditions. By assessing the quality of the evidence, the acceptability of such research and the variety of their designs, it will be possible to debate the probability that there could be or may not be any concern in regard to contamination of omega n-3 fish oil and human health. The results presented in this research is intended to provide conclusive proof for or against the use of omega n-3 fish oils as a necessary supplement to children’s or pregnant women’s diets. This will enable the audience to make appropriate decisions when providing advice to patients regarding this subject. A secondary objective is to provide knowledge of the companies and organizations conducting and sponsoring this research so practitioners may know where to go for more information as well as to demonstrate the broader community/corporate/governmental concern associated with this topic. Types of Evidence In 2004, Dr. Carrie Ruxton wrote an article for the nursing standard in which she gave indications that omega n-3 fatty acids played a fundamental role in human development that was essential for proper brain development and cognitive function. She continues her report to say that superlative levels of the intake of omega n-3 by the general populace could also reduce heart disease, behavioral problems in children, depression and inflammatory conditions. These claims have made supplementation seem eminently desirable with little regard to the possible risks. These conclusions are somewhat supported in the publication of the following daily recommendations of fish oils given by the Scientific Advisory Committee on Nutrition (SACN) (2004), in which it is proposed that 1-4 fish oil meals should be consumed during each week. There is also significant support coming from studies conducted in the Faroe Islands in which it is shown that diets rich in omega-3 fatty acids tend to increase birth weight and may lower the risks of certain complications of pregnancy (Olsen et al, 1986; Olsen, 1993). Birth weights are thought to be increased either because of prolonged pregnancies (Olsen et al, 1986) or by the tendency of high fish diets to increase the fetal growth rate (Anderson, Anderson & Fuchs, 1986; Olsen, Olsen & Erische, 1990). Complications of pregnancy that may be reduced by the intake of marine oils include preterm delivery, intrauterine growth retardation, preeclampsia and gestational hypertension (Olsen et al, 2000). Somewhat contradictory, though, is the recommendation in the SACN (2004) report that lactating or pregnant mothers should reduce the amount of fish consumption to 1-2 meals weekly in order to evade high levels during intake of contaminates such as dioxins, polychlorinated biphenyls (PCBs) and heavy metals (mercury). The danger of methylmercury is further illustrated in Choi (1989). In this study regarding cerebral palsy, it was observed that “miniscule doses of mercury that had produced no signs or symptoms within the initial exposure could nevertheless result in the development of cerebral palsy and progressive mental retardation years later.” The study (Choi, 1989) also indicated that the nervous system looked to be fundamentally susceptible to abnormal development in early teenage years. A longitudinal study being conducted in the Seychelles Islands, in which the diet of all residents consists of large proportions of fish, has also revealed few, if any, significant adverse effects of high fish consumption upon the developing fetus (Myers et al, 1997). However, the reports available to date indicate that results are not yet complete and analysis may be misleading. There could be some developmental milestones that have not been studied that are adversely affected by high doses of methylmercury and studies involving older children are necessary to determine any long-term effects. Evidence in other studies show that susceptibility to methylmercury from the prenatal stage through birth is real and damage is permanent. In these studies, methylmercury exposure was significantly associated with deficits in motor, attention, and verbal tests (Debes et al 2006). Susceptibility lowers the genetic predisposition and interferes with the duplication of the genetic template, therefore mercury is found to accumulate in the fetus at substantially higher levels, of up to 30 times more than the mothers (Verschaeve et al 1976). Mercury is so proficient in generating an autoimmune response that it is characteristically used in animal research studies involving autoimmune disease. Autoimmune disease is a result of genetic predisposition plus environmental exposure (Huggins & Levy, 1999). As this suggests, exposure to methylmercury can come from environmental factors such as immunisations, dental amalgams, ecological factors, work environments (chemicals), foods and water (Shipp et al 2000). Prosperous countries that have used thiomersal (thimerosal) in vaccines are now moving away from using it as a methylmercury preservative as a precautionary measure because of the unease about the potential undesirable effects of mercury in infants (Bingham 2005). Conclusion Available studies regarding the benefits and risks of methylmercury intake as it relates to healthy development of foetuses and infants demonstrate a decided lack of agreement regarding the immediate and long-term effects. Intake by pregnant and nursing mothers seems to provide significant immediate benefits for both a healthy pregnancy as well as a healthy infant as has been demonstrated through numerous studies conducted in the Faroe Islands and elsewhere. However, the long-term effects remain unclear. Studies such as the Seychelles Child Development study seem to indicate that there are no long-term effects, yet have not progressed to studying children beyond 5 ½ years old. Meanwhile, other studies have linked significant issues to prenatal exposure to methylmercury including cognitive, developmental and other skills. A portion of the problem could be in determining the source of the methylmercury. While the heaviest concentrations occur naturally in fish, other sources are known to exist including its use in immunization concentrations, dental work and environmental pollution. The anomalies noted in the literature could be the result of these alternate sources. References Andersen H.J., Andersen L.F. & Fuchs A.R. (1989). “Diet, Pre-eclampsia and Intrauterine Growth Retardation.” Lancet. Vol. 1, n. 8647, p. 1146. Bingham et al. (2005). Drug Safety. Vol. 28, I. 2, pp. 89-101. Choi, B.H. (1989). “The Effects of Methylmercury on the Developing Brain.” Progress in Neurobiology. Vol. 32, pp. 447-470. Claudio L., Kwa W.C., Russell A.L. & Wallinga D. (1 April 2000). “Testing Methods for Developmental Neurotoxicity of Environmental Chemicals.” Toxicology Applied Pharmacology. Vol. 164, N. 1, pp. 1-14. Debes F, Budtz-Jorgensen E., Weihe P., White R.F., Grandjean, P. (2006). “Impact of Prenatal Methylmercury Toxicity on Neurobehavioral Function at Age 14 Years.” Neurotoxicology and Teratology. Vol. 28, pp. 363-375. Huggins Hal A. & Levy Thomas E. (February 1999). Uninformed Consent: The Hidden Dangers in Dental Care. Hampton Roads Publishing Company. Martinez, Manuela. (1996). “Docosahexaenoic Acid Therapy in DHA-Deficient Patients with Disorders of Peroxisomal Biogenesis.” Lipids. Vol. 31, Suppl. 145-152. Myers G.J., Davidson P.W., Shamlaye C.F., Axtell C.D., Cernichiari E., Choisy O., Choi A., Cox C. & Clarkson T.W. (1997). “Effects of Prenatal Meythlmercury Exposure from a High Fish Diet on Developmental Milestones in the Seychelles Child Development Study.” Neurotoxicology. Vol. 18, N. 3, pp. 819-829. Olsen S.F., Hansen H.S., Sorensen T.I. et al. (1986). “Intake of Marine Fat, Rich in (n-3)-Polyunsaturated Fatty Acids, May Increase Birthweight by Prolonging Gestation.” Lancet. Vol. 2, N. 8503, pp. 367-369. Olsen S.F., Olsen J., Erische G. (1990). “Does Fish Consumption during Pregnancy Increase Fetal Growth? A study of the size of the newbord, placental weight and gestational age in relation to fish consumption during pregnancy.” International Journal of Epidemiology. Vol. 19, N. 4, pp. 971-977. Olsen S.F. (1993). “Consumption of Marine n-3 Fatty Acids During Pregnancy as a Possible Determinant of Birth Weight: A Review of the Current Epidemiologic Evidence.” [Review]. Epidemiological Review. Vol. 15, N. 2, pp. 399-413. Olsen S.F., Secher N.J., Tabor A., et al. (2000). “Randomised Clinical Trials of Fish Oil Supplementation in High Risk Pregnancies.” BJOG: An International Journal of Obstetrics and Gynaecology. V. 107, N. 3, pp. 382-395. Poulter, Sean. (12 June 2006). “Fish Oil Supplements Considered for Schoolchildren.” The Daily Mail. Available 23 January 2007 from Ruxton, Carrie. (2004). “Health Benefits of Omega-3 Fatty Acids.” Nursing Standard. Vol. 18, N. 48, pp. 38-42. 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Appendix A Search term keywords used Polychlorinated biphenyls (PCBs) Dioxins Heavy metals Contaminates Polyunsaturated fatty acids Chemical pollution Methyl mercury Read More