Nutritional Genomics (Introduction) PDF

Nutritional Genomics By: Dr. Hamid Jan Bin Jan Mohamed  Learning outcomes To identify different areas in nutritional sciences To understand the role of the different areas in nutritional genomics To understand what is meant by nutritional genomics To identify examples of nut...

Nutritional Genomics By: Dr. Hamid Jan Bin Jan Mohamed  Learning outcomes To identify different areas in nutritional sciences To understand the role of the different areas in nutritional genomics To understand what is meant by nutritional genomics To identify examples of nutritional genomics knowledge To discuss the prospect of nutritional genomics  Nutritional sciences CLINICAL NUTRITION - Nutrition and health - Nutrition and disease COMMUNITY - Diet therapy NUTRITION NUTRITIONAL - Food choices - Food & nutrition policy SCIENCES - Nutritional epidemiology MOLECULAR - Nutritional education NUTRITION & intervention - Food security - Nutritional biochemistry - Nutritional proteomics - Nutritional genomics = Diet-gene interaction The cell and the gene DNA Deoxyribonucleic acid (DNA). Molecule that carries genetic information. Complementary base pairs: – Adenine (A)-Thymine (T) – Guanine (G)-Cytosine (C) Each DNA molecule consists of two strands in the shape of double helix  Gene…..not ‘JIN’ Piece of DNA with sequences of base pairs encoding specific protein. From gene to protein DNA--mRNA--Protein RNA transmits genetic information from DNA to proteins. Eg: GAC TTC (in DNA) CUG AAG (in mRNA) Leu Lys (amino acid)  Diet-gene interactions Nutritional genomics: A field of study focusing on the interactions between nutrients and the genome. It is divided into two terms: 1) Nutrigenetics – effects of individual genetic variation on response to diet. 2) Nutrigenomics – effect of diet/specific nutrient on the gene. Nutrigenetics & Nutrigenomics Nutrigenomic s Nutrigenetics Molecular nutrition  Nutrigenetics Genetic Polymorphism: – Complete gene variation from individual to individual. – Ethnicity, hair or eye colour, blood type. Single Nucleotide Polymorphisms (SNP) – defined as a difference in a single nucleotide from the generally accepted gene sequence. – Are the commonest form of genetic variability and relate to a single nucleotide substitution in a DNA sequence. – Eg.: ACG could be replaced by AGG causing lack of amino acid synthesis or the production of a wrong amino acid  Nutrigenetics and folate A SNP was identified that influences the dietary folate requirement The affected gene codes for a key enzyme methylenetertahydrofolate reductase (MTHFR) MTHFR 677CT causing C677T polymorphism It is a single nucleotide change at position 677 – cytosine (C) replaced by thymine (T) – Hence, protein sequence alanine (ala) replaced by valine (val) at position 222 of amino acid sequence  Homocysteine metabolism Tetrahydrofolate Methionine  Vit. B 12 5-methytetrahydrofolate Homocysteine  MTHFR  CVD 5,10-methylenetetrahydrofolate DNA methylation  Examples of known SNPs Cellular process Gene with known Nutrition/Health impact polymorphisms Folate metabolism MTHFR, cystathione Risk of neural tube defect, betasynthase, methionine CVD, cancer synthase Iron homeostasis HFE gene, transferrin Iron overload (HH), receptor gene anaemia Bone health Vit. D receptor, oestrogen Osteoporosis, Negative receptor, type 1 collagen effect on bone metabolism Lipid metabolism Apolipoprotein (AIV, B, Blood cholesterol and C3, E), LDL receptor, CVD lipoprotein lipase Obesity β 2- and β3- Increased body fat Adrenoreceptors Genetics and Obesity Genetics and Obesity  Nutrigenomics Diet and gene expression – Direct effect on DNA DNA structure – Carcinogens/free radicals DNA damage mutations – Changes in DNA sequence Epigenetics – methylation, histone modification – does not involve changes to DNA sequence – Folate is essential for DNA methylation Application Increased understanding of the link between diet and disease – change in dietary guideline – personalised diet/lifestyle change – better public healthy strategy to reduce the incidence of disease Challenges Knowledge – lack of knowledge and conflicting findings Prevalence and severity – Low prevalence of mutations – Low penetrance Ethics of gene testing Ethics? MyCellf ® Program A combined analysis of nineteen genes that may play an important role in how your body manages bone health, heart health, antioxidant and detoxification function, insulin sensitivity and inflammation. Perfect for those who want a complete snapshot of their overall health profile and recommendations for achieving optimal health without a specific disease focus. Price: $269.00 (RM 940.00)  Conclusions Human are complex and so too are their diets. Hence, a multidiscipline approach should be practiced. Public health nutrition, underpinned by nutritional genomics, may be more effective in diesease prevention and management. What do you think? I am hungry… need to eat…I want ‘roti canai’ and ‘teh tarik’… yum..yum ob/ob