Nutritional Genomics Flashcards
The relationship between our nutrition status and our genetic makeup.
Nutritional Genomics
How an individual’s genetics affects utilization and response to dietary component
Nutrigenetics
How dietary components affect expression of genetic information.
Nutrigenomics
Affects absorption, metabolism, utilization of a nutrient. Can increase or decrease disease risk.
Genetic variant
Major protein that makes up high density lipoprotein (HDL)
Apo A-1
When there is a polymorphism on the genes that express Apo A-1, it changes how the individual responds to …
Dietary fat
- MUFAs stabilize HDL
PUFAs decrease HDL levels -75% of population
Homozygous G (GG)
PUFAs increase HDL levels
Homozygous A (AA) & Heterozygous (GA)
Where is Apo E protein present? (4)
- Chylomicrons
- Chylomicron remnants
- VLDL
- HDL
What are the 3 main alleles that code for the Apo E protein?
- E2
- E3
- E4
Results in lower than average cholesterol
E2
What allele that codes for Apo E protein that results in: increased risk of diabetes, decreased protective effects of moderate drinking, & increased health risks with smoking.
E4
What is the enzyme responsible for methionine formation from homocysteine?
MTHFR: methyl-tetrahydrofolate reductase
C677T & A1298C both are enzyme MTHFR variants and have been investigated in relation to …
Cancer susceptibility
The C677 C->T variant occurs in 8 - 15% of the population and results in a reduction of what?
MTHFR activity
Has “normal” MTHFR activity
Homozygous (CC)
45% reduction in MTHFR activity
Heterozygous (CT)
70% decrease of MTHFR activity
Homozygous for the MTHFR T variant (TT)
Persons with the TT genotype have low levels of _____ & ________ in the blood.
Folate & Vitamin B12
The TT genotype results in increased …
homocysteine
Nutrigenomics is also known as …
Epigenetics
Set factors that affect gene expression & influenced by dietary/ lifestyle factors; factors outside genetics alone
Epigenetics
What is an example of epigenetic modification?
DNA Methylation
List the dietary factors influencing methylation.
- Alcohol - Methionine
- Arsenic - Pholyphenols
- Betanine - Selenium
- Choline - Vitamin A
- Fiber - Vitamin B6
- Folate - Vitamin B12
- Genestein - Zinc
What does alcohol decrease?
DNA methylation
Alcohol inhibits ____ ___ conversion to DHF, used to bring ____ ___ in to the ____ cycle.
Folic acid; folate cycle
Decrease in DNA methylation inhibits _______ _______, which uses folate/B12 to convert homocysteine to methionine.
Methionine synthase
Decrease in DNA methylation by alcohol inhibits …, which uses ATP to convert methionine to SAM.
Methionine adenosyl transferase
Decreases in DNA methylation due to alcohol inhibits …, which transfers methyl group to form SAM to DNA.
DNA methyl transferase
What term denotes compounds that help catalyze the breakdown of fat molecules in the body?
Lipotropes
Dietary methyl donors and cofactors that play key roles in 1-carbon metabolism.
Lipotropic nutrients
List 4 lipotropic nutrients.
- Methionine
- Choline
- Folate
- Betaine
Dietary lipotropes influence the availability of …
SAM
Dietary lipotropes influence the availability of SAM which may influence … (2 things)
- genomic DNA methylation patterns
- the expression of multiple cancer-related genes
Methylation in maternal diet can modify what of the offspring?
Phenotype
What is the result when the agouti mouse’s diet is very low in DNA Methylation?
An overweight offspring with a light-colored coat
What is the result when the agouti mouse’s diet is very high in DNA Methylation?
A normal weight offspring with a dark coat
In mice with the same genotype modified epigenotype in utero results in …
different phenotype
In Nutrigenomics recommendations are based upon an individual’s …
genetic makeup
