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Definition

Edit 1:

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Nutrigenomics has been defined as the application of high-throughput genomic tools in nutrition studies and research.[1]< plagiarism

In a Nature Reviews Genetics paper, nutrigenomics is defined an emerging field of research that expands upon the existing field of nutritional science using genomic based data. [1] Certain advances in the field such as microarrays, and high throughput sequencing allow for expansive analysis of the genome and in-vivo experiments in knockout mice are major sources of genomic based data. [1]This type of genomic data collection can be applied to view the effects that certain nutrients or foods may have on large portions or different locales of the genome rather than one specific location.[2]

Edit 2: Nutrigenomics involves the characterization of gene products and the physiological function and interactions of these products. This includes how nutrients impact the production and action of specific gene products and how these proteins in turn affect the response to nutrients.[3]-plagiarism

Nutrigenomics is also defined as a field that examines "effect of nutrients on genome, proteome, metabolome and explains the relationship between these specific nutrients and nutrient-regimes on human health."[3] In other words, a nutrigenomics approach is a holistic one that examines the effect of nutrients at all levels, from gene expression to metabolic pathways. [3]

Edit 3: The term "high throughput tools" in nutrigenomics refers to genetic tools that enable millions of genetic screening tests to be conducted at a single time.[4] When such high throughput screening is applied in nutrition research, it allows the examination of how nutrients affect the thousands of genes present in the human genome. -unecessary, just link to another wikipedia article

Background

Edit 4: Throughout the 20th century, nutritional science focused on finding vitamins and minerals, defining their use and preventing the deficiency diseases that they caused. As the nutrition related health problems of the developed world shifted to overnutrition, obesity and type two diabetes, the focus of modern medicine and of nutritional science changed accordingly.-plagiarism (7)

Edit 5: To address the increasing incidence of these diet-related-diseases, the role of diet and nutrition has been and continues to be extensively studied. To prevent the development of disease, nutrition research is investigating how nutrition can optimize and maintain cellular, tissue, organ and whole body homeostasis. This requires understanding how nutrients act at the molecular level. This involves a multitude of nutrient-related interactions at the gene, protein and metabolic levels. As a result, nutrition research has shifted from epidemiology and physiology to molecular biology and genetics and nutrigenomics was born.- plagiarism[3]

Nutritional science originally emerged as a field that studied individuals lacking certain nutrients and the subsequent effects[3], such as the disease scurvy which results from a lack of vitamin C. As other diseases closely related to diet,(but not deficiency) such as Obesity, became more prevalent, nutritional science expanded to cover these topics as well. [3] Nutritional research typically focuses on preventative measure, trying to identify what nutrients or foods will raise or lower risks of diseases and damage to the human body.

Edit 6: The emergence and development of nutrigenomics has been possible due to powerful developments in genetic research. Inter-individual differences in genetics, or genetic variability, which have an effect on metabolism and on phenotypes were recognized early in nutrition research, and such phenotypes were described. With the progress in genetics, biochemical disorders with a high nutritional relevance were linked to a genetic origin. Genetic disorders which cause pathological effects were described. -plagiarized, nutritional genomics, http://www.researchjournal.co.in/upload/assignments/2_90-92-7.pdf

Nutrigenomics emerged as a possible way to fix gaps in the current field of nutritional science. The development of technology to analyze the genome such as different types of sequencing and different microarrays suggest a new way to reinforce current theories or hypotheses. Existing information from genetic research directs emerging research in nutrigenomics. Individuals within the same population or even the same family have genetic variability.[2] There is a lack of consistent relationships between certain foods and nutrients and increased disease risk, most likely due to this type of variation. [5] Nutrigenomics is highly personalized because it looks at biomarkers within each individual.[5] One group of researchers suggest that current technology can be used to build an ideal diet/intake of certain nutrients, or a 'nutriome.' [6]A 'nutriome' would ensure proper function of all pathways involved in genome maintenance. [6]

edit 6 contd: Such genetic disorders include the polymorphism in the gene for the hormone Leptin which results in gross obesity. Other gene polymorphisms were described with consequences for human nutrition. The folate metabolism is a good example, where common polymorphisms (C677T and A1298C) exists for the gene that encodes the methylene-tetrahydro-folate reductase (MTHFR). (no source given, deleted, replaced with prader willi)

Edit 7: It was realized however, that there are possibly thousands of other gene polymorphisms which may result in minor deviations in nutritional biochemistry, where only marginal or additive effects would result from these deviations. The tools to study the physiological impact were not available at the time and are only now becoming available enabling the development of nutrigenomics. Such tools include those that measure the transcriptome - DNA microarray, Exon array, Tiling arrays, single nucleotide polymorphism arrays and genotyping. Tools that measure the proteome are less developed. These include methods based on gel electrophoresis, chromatography and mass spectrometry. Finally the tools that measure the metabolome are also less developed and include methods based on nuclear magnetic resonance imaging and mass spectrometry often in combination with gas and liquid chromatography. (Repetitive and no sourcing, reworded and cited)

Research has already provided evidence identifying potential genetic origins of metabolic disorders or compromised phenotypes.[2] Disorders that scientists previously thought to be heritable, can be identified as genetic disorders with set pathological effects.[2] For example, Prader-Willi syndrome, a disease whose most distinguishing factor is insatiable appetite, has been specifically linked to an epigenetic pattern in which the paternal copy in the chromosomal region is erroneously deleted, and the maternal loci is inactivated by over methylation. [7] Yet, although certain disorders may be linked to certain single nucleotide polymorphisms (SNPs) or other localized patterns, variation within a population may yield many more polymorphisms.[8] Each may have a negligible effect by itself, yet the cumulative effects may be significant.[8] Now, with advances that have been made, these small changes and additive effects are possible to study. [8] Small epigenetic changes such as methylation patterns or phosphorylation can be determined.

Rationale and Aims

Edit 8: In nutrigenomics, nutrients are seen as signals that tell a specific cell in the body about the diet. The nutrients are detected by a sensor system in the cell. Such a sensory system works like sensory ecology whereby the cell obtains information through the signal, the nutrient, about its environment, which is the diet. The sensory system that interprets information from nutrients about the dietary environment include transcription factors together with many additional proteins. Once the nutrient interacts with such a sensory system, it changes gene expression and metabolite production in accordance with the level of nutrient it senses. As a result, different diets should elicit different patterns of gene expression and metabolite production. Nutrigenomics seeks to describe the patterns of these effects which have been referred to as dietary signatures. Such dietary signatures are examined in specific cells, tissues and organisms and in this way the manner by which nutrition influences homeostasis is investigated. Genes which are affected by differing levels of nutrients need first to be identified and then their regulation is studied. Differences in this regulation as a result of differences in genes between individuals are also studied.[2] It is hoped that by building up knowledge in this area, nutrigenomics will promote an increased understanding of how nutrition influences metabolic pathways and homeostatic control, which will then be used to prevent the development of chronic diet related diseases such as obesity and type two diabetes. Part of the approach of nutrigenomics involves finding markers of the early phase of diet related diseases; this is the phase at which intervention with nutrition can return the patient to health. As nutrigenomics seeks to understand the effect of different genetic predispositions in the development of such diseases, once a marker has been found and measured in an individual, the extent to which they are susceptible to the development of that disease will be quantified and personalized dietary recommendation can be given for that person. Plagiarism. The aims of nutrigenomics also includes being able to demonstrate the effect of bioactive food compounds on health and the effect of health foods on health, which should lead to the development of functional foods that will keep people healthy according to their individual needs. Nutrigenomics is a rapidly emerging science still in its beginning stages. It is uncertain whether the tools to study gene expression and metabolite production have been developed to the point as to enable efficient and reliable measurements. Also once such research has been achieved, it will need to be integrated together to produce results and dietary recommendations. All of these technologies are still in the process of development.Plagiarism from [2]

Cell signaling is an important component of regulation of gene expression and metabolism, relying on both internal and external signals to ensure the body is maintaining homeostasis. Individual nutrients can each be considered signals, with the summation of their effects being the diet.[2] The effort of nutrigenomics is to identify this "dietary signature", or pattern of effects ranging from effects at the cellular level to entire body systems.[2] However it is often hard to monitor the diet of an individual, and current protocols should be improved[9]. The desired outcome from this type of research is to identify genetic factors for chronic diseases and conditions, whether it be a certain gene itself or an epigenetic marker, and how foods influence it. Nutrigenomics looks mainly to be a way of identifying individuals predisposed for conditions and preventing onset. [2] First, genes with regulation influenced must be identified, and then more focused studies may emerge.[2]

In addition, nutrigenomics also looks to identify certain compounds that are bioactive, and other foods that are of particular benefit to health.[2] This knowledge can be personalized to produce specific diet plans and functional foods to both prevent predisposed conditions and maximize health. [2]

(Adding a subsection to application... about Nutrigenomics and) Cancer

[edit]

Nutrigenomics may be able to supplement current oncology. There is a wealth of information about processes that occur within genome maintenance that prevent cell abnormalities linked to cancer and certain nutrients that play a role as cofactors.[10] Genome damage caused by micronutrient deficiency may be just as severe as damage owed to exposure to certain environmental carcinogens.[10] If these micronutrients can be identified, with concrete evidence, the risk for cancer in some individuals could be significantly reduced. One such micronutrient may be folate. In one experiment, folate was given to cells in different concentrations and those with less folate exhibited as much damage to their chromosomes as they would have exhibited with a heavy amount of radiation. [10]

Nutrigenomics can be used to develop new, alternative treatments that target the altered cancer cell metabolism. [9] The alternative way of energy production in cancer cell metabolism, the Warburg effect, in which glycolysis and lactic acid fermentation are the main means of energy production opposed to oxidative reduction. Certain nutrients may provide ways to starve or inhibit this type of metabolism. Polyunsaturated fatty acids (PUFA) which affect gene expression related to inflammation and other nutrients that have displayed potential in repressing cancer cell metabolism.[9] Another practical application of nutrigenomics to cancer may be identifying nutrient that is a cofactor of a compromised pathway where consuming a surplus of could potentially reduce the compromised pathway’s negative consequences.[10] A nutrigenomics approach could provide a safe, holistic model to mitigate tumor growth in place of existing cancer treatments that often have harsh side effects and are not always effective.[9]

Ethics[edit | edit source]

[edit]

To put nutrigenomics into practice, genetic testing is required as the test results act as the reference for diagnosis. Edit 9:

As the subject is recently commercialized by companies which sell direct to customer (DTC) genetic tests, as well as being applied by related professionals (such as dietetic practitioners), there has been increased awareness in the use of this information. (DTC should be addressed in a subcategory)

Genetic testing has been met with many concerns surrounding ethics and regulations. These concerns inherently become a part of, if not augmented by Nutrigenomics, a field that looks to provide highly personalized information.

Adding in subsection about consent

[edit]

One of the major concerns regarding genetic tests would be privacy issue. To preform any type of genetic testing, consent is need directly by the individual who provides the sample. However, if an individual has results that indirectly tie family members to it, by identifying information about a genetic predisposition or condition, information about that family member has been inadvertently revealed.[11] Thus, this type of genetic testing would require consent from a network of individuals. For some sets of the population such as mentally impaired adult or children, it is not possible to obtain direct consent.[11]'The best interest' of the patient must be determined by close family members, care takers and professionals, leaving room for discrepency.[11] Tissue samples obtained from patients, particularly those who are deceased are also a source of controversy.[11] There is no established ethical code to suggest if data from these patients should be allowed to be published, or if they should remain only as sources of validation for lab techniques. There also exists no regulation for releasing information about heritable condition to family members. The stances on how to approach these situations are arbitrary and regulation provides few guidelines to direct them.

Edit 10: Privacy

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One of the major concerns regarding genetic tests would be privacy issue. There are concerns on who has the right to have access to test results. Abuse of these tests could result in discrimination. For example, genetic information might be used by insurance companies to risk rate their clients.

Edit 11: Medical claims[edit | edit source]

One of the possible ethical concerns arise would be private companies providing unverified information regarding test results. For example, there are concerns on test-providing companies making unproven medical claims, as well as selling unnecessary or over-priced supplements. Interpretations on genetic test results needs to be handled very carefully. Misinterpretation could possibly mislead patients and hence false medical claims are made. Misleading and/or inaccurate information may as well undermine customers' ability to make informed decisions.

Validity of nutrigenomic tests[edit | edit source]

[edit]

Nutrigenomics is the study of interactions between a person's genetics and nutrition. In order to make accurate interpretations of genetic test results, sufficient genetic and nutritional knowledge is necessary for the practitioner. However, there are currently no regulations limiting who can perform these tests. As well, nutrigenomics is not currently a licensed profession. Therefore, there are concerns regarding the validity of consultation provided by private companies on genetic test results. In other words, there are concerns about how well the companies (who sell this services, and therefore have a profit motive) interpret test results.

Condense the above two topics because of overlap, change.

Distribution of nutrigenomics' tests

[edit]

As the subject is recently commercialized by companies which sell direct to customer (DTC) genetic tests, as well as being applied by related professionals (such as dietetic practitioners), there has been increased awareness in the use of this information.[12]

Validity

[edit]

Nutrigenomics is still a new field. There are no set guidelines on how to interpret data from genetic testing. Without a validated way to produce accurate results, there exist concern about how valid results produced are. The Government Accountability Office (GAO) attempted to check the validity of numerous DTC tests by sending out information and samples of sham identities.[13] The information they recieved was varied and not medically verified, and two companies tried to market general supplements as 'individualized'.[13] The GAO study was also rudimentary, without taking into concern that differing environmental factors may affect results.[13]

One suggestion to try and minimize fraud is to channel distribution of genetic testing to healthcare professionals.[13]  [1]American College of Medical Genetics (ACMG) has taken a stance that healthcare professionals should be involved for proper implementation of information from genetic testing. [11] Healthcare professionals are not necessarily qualified to properly interpret and distribute this information as it is not currently required that they have an in-depth knowledge of genetics.[12] There are a sheer 45 genetic residencies in the US, with a low number of individuals who have completed training per year. [12] Practitioners often focus on acute medical conditions and do not spend much of their time making health recommendations to each patient.[12] It is suggested that nutritionists and genetic counselors may be the best choice to ensure proper distribution of genetic tests' results.[12]

Privacy

[edit]

One of the major concerns regarding genetic tests would be privacy issues. There are concerns regarding who has the right to have access to test results. Abuse of these tests could result in discrimination. For example, genetic information might be used by insurance companies to risk rate, or access how likely their clients are to be costly.[13] Other examples of privacy concerns include disclosure to the workplace that may led to discrimination in employment.[11] Social concerns exist as certain conditions may be stigmatized by the general population.

  1. ^ a b c Müller, M., & Kersten, S. (2003). Nutrigenomics: goals and strategies. Nature Reviews Genetics. 4(4): 315-322.
  2. ^ a b c d e f g h i j k l Aglave, B.A.; Mahajan, V.A.; Lokhande, M.O. (April–September 2009). "Nutritional Genomics" (PDF). International Journal of Medical Sciences. 2.1: 90–92.
  3. ^ a b c d e f Neeha, V. S., & Kinth, P. (2013). Nutrigenomics research: a review. Journal of Food Science and Technology. 50(3): 415–428.
  4. ^ Liu, B., & Qian, S. B. (2011). Translational regulation in nutrigenomics. Advances in Nutrition: An International Review Journal. 2(6): 511-519.
  5. ^ a b Ardekani, A.M., & Jabbari, S. (2009). Nutrigenomics and Cancer. Avicenna Journal of Med Biotechnology, 1(1), 9-17. 
  6. ^ a b Bull, C., & Fenech, M. (2008) Genome-health nutrigenomics and nutrigenetics: nutritional requirements or ‘nutriomes’ for chromosomal stability and telomere maintenance at the individual level. Proceedings of the Nutrition Society, 67, 146-156. doi:10.1017/S0029665108006988
  7. ^ Grant, S.F.A.; Xia, Q. (2013). "The genetics of human obesity". Ann N Y Acad Sci. 1281(1): 178–190. doi:10.1111/nyas.12020 – via NIH NCBI.
  8. ^ a b c Bisen, Prakash A.; Debnath, Mousumi; Prasad, Godavarthi B.K.S. (2010). Molecular Dianostics: Promises and Possibilities. Springer Science & Business Media. p. 26. ISBN 9048132614.
  9. ^ a b c d Kang, J.X. (2013). Nutrigenomics and Cancer Therapy. Journal of Nutrigenetics and Nutrigenomics, 6, I-II. doi:10.1159/000355340
  10. ^ a b c d Bull, C., & Fenech, M. (2008) Genome-health nutrigenomics and nutrigenetics: nutritional requirements or ‘nutriomes’ for chromosomal stability and telomere maintenance at the individual level. Proceedings of the Nutrition Society, 67, 146-156. doi:10.1017/S0029665108006988
  11. ^ a b c d e f Williams, J.; Skirton, H.; Masny, A. (2006). "Ethics, Policy and Educational Issues in Genetic Testing". Journal of Nursing Scholarship. 38(2): 119–125 – via Wiley Online Library.
  12. ^ a b c d e Ries, Nola M.; Castle, David (2008-11-30). "Nutrigenomics and Ethics Interface: Direct-to-Consumer Services and Commercial Aspects". OMICS: A Journal of Integrative Biology. 12 (4): 245–250. ISSN 1536-2310. doi:10.1089/omi.2008.0049.
  13. ^ a b c d e Castle, David; Ries, Nola M. (2007-09-01). "Ethical, legal and social issues in nutrigenomics: The challenges of regulating service delivery and building health professional capacity". Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis. Nutrigenomics. 622 (1–2): 138–143. doi:10.1016/j.mrfmmm.2007.03.017
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