2a. Nutrigenomics Flashcards
What is nutrigenomics?
The study of the interaction between nutrition and genes
Especially in regard to the prevention or treatment of disease
What can nutrigenomics offer?
Personalised nutrition and lifestyle plans
What is DNA made up of?
2 paired nucleotide chains (the double helix)
What is a nucleotide made up of?
Deoxyribose (sugar)
Phosphate group
One of 4 bases - adenine, cytosine, thymine, guanine
How are nucleotides organised?
Into codons
What are codons?
Sequence of 3 nucleotides that code for a specific amino acid
What happens when the translation of a protein is not coded correctly?
It makes a different protein
Why is it important that methionine is coded correctly?
Required for methylation
Switching genes on and off
What does low methionine increase the risk of?
Cancerous cell changes
What does SNP stand for?
Single nucleotide polymorphism
What is a SNP?
Differences in the single base in the sequence of a gene (codon)
What can a SNP result in?
A change in enzyme or protein function
What is a wild type variant?
No variant
Normal/stable
What is a heterozygous variant?
Single variation on one side of the chromosome pair
What can a heterozygous variant indicate?
A potential change of function
What is a homozygous variant?
Variation on both sides of the chromosome pair
What can a homozygous variant indicate?
A greater change of function
In what areas of nutrition can information about genetics be useful?
Methylation
Detoxification
Vitamin conversion/receptor function
Neurotransmitter/hormone synthesis and metabolism
What does the BCO1 gene do?
Codes for the enzyme that converts beta carotene to retinol (vit A)
What processes can be impacted with a SNP on the BCO1 gene?
Reduction in enzyme activity
Lower rate of beta-carotene to retinol conversion
How might a SNP on the BCO1 gene manifest itself?
Impaired night vision
Frequent infections
Skin conditions e.g. acne
How can a SNP on the BCO1 gene be supported?
Increase intake of pre-formed vit A from food e.g liver, fish oils
Supplementation - especially if plant-based
What does the VDR gene do?
Codes for the vit D receptor
What processes can be impacted with a SNP on the VDR receptor?
Absorption, conversion and/or transportation of vit D to receptor
How can a SNP on the VDR receptor manifest itself?
Rickets/osteomalacia
Osteoporosis
Immune dysfunction
How can a SNP on the VDR receptor be supported?
Ensure optimal vit D levels with regular testing
Sun exposure
Food - oily fish, eggs
Supplementation
What does the SLC23A1 gene code for?
Production of the transporter which supports vit C absorption and distribution
How does a SNP on the SLC23A1 gene manifest itself?
Higher demand for vit C
How can a SNP on the SLC23A1 gene be supported?
Optimise dietary intake of vit C - fresh fruit/veg - peppers, kiwi, berries, citrus, tomatoes, cruciferous veg
Supplementation - liposomal
Reduce stress (if applicable)
Stop smoking (if applicable)
What other mineral could be impacted by a SNP on the SLC23A1 gene?
Fe absorption
(reduced conversion from Fe3+ to Fe2+)
What does the FADS1 gene code for?
Delta 5 desaturase
What does the FADS2 gene code for?
Delta 6 desaturase
What process can be impacted with a SNP on FADS1 gene?
Increase of high dietary O6 to inflammatory AA
(doesn’t convert to EPA/DHA)
What process can be impacted with a SNP on FADS2 gene?
Lower levels of GLA, AA and EPA
How can SNPs on FADS1 and FADS2 be supported?
EPA/DHA/ALA from fish oils, algae, flaxseed
What does the TNF gene code for?
Production of the pro-inflammatory cytokine
How can a SNP on the TNF gene manifest itself?
Increased inflammation
Increased risk of asthma, RA, psoriasis, cancer
How can a SNP on the TNF gene be supported?
Reducing pro-inflammatory foods
Increasing anti-inflammatory foods
Curcumin
Green tea
SMASH fish
What is methylation?
The process of adding a methyl group to a substrate
What processes is methylation involved in?
Detoxification
Energy production e.g. CoQ10, ATP
Myelination and neurotransmitter production
Immune function e.g. inflammation, immune cell synthesis
What dietary co-factors are required for methylation?
B2, 6, 9, 12
Choline
Betaine
Zn
What is the master methyl donor?
SAMe
What factors can disrupt methylation?
Insufficient substrates e.g. B9, methionine
Lack of dietary co-factors
SNPs affecting enzyme activity
Drugs e.g. OCP, metformin
Increased demand e.g. stress, inflammation
Toxin exposure e.g. alfatoxin (fungi), BPAs, heavy metals (mercury/lead)
What can impaired methylation contribute to?
CV disease
Cancer
Infertility/miscarriages
Chronic fatigue
Neurological disease
How can we test for poor methylation?
Genetic testing for methylation SNPs
Homocysteine testing
What are the steps that convert folate to methylfolate? (folate cycle)
Eat folate foods - DHF - THF - 5,10 Methylene THF - 5-MTHF
What does the MTHFR gene code for?
Enzyme methylenetetrahydrofolate reductase that converts folate into a methylated form
What process can be impaired by a SNP on the MTHFR gene?
Reduced activity of the MTHFR enzyme
How can a SNP on the MTHFR gene be supported?
Optimise dietary folate
Consider methylated folate supplement
Optimise B2 to support MTHFR gene
What are the steps that convert methionine to homocysteine?
Eat protein foods - Methionine - SAMe - SAH - Homocysteine
What genes are needed to convert homocysteine back to methionine?
MTR
MTRR
What process can be impacted by a SNP on the MTR gene?
Decreased enzyme activity to convert homocysteine back to methionine
What processes can be impacted by a SNP on the MTRR gene?
Reduced conversion of B12 to its methylated form
How can SNPs to the MTR and MTRR genes be supported?
Supplementation of methylated folate and B12
Which 3 genes are important for SAMe production?
MTHFR
MTR
MTRR
What is SAMe reliant on?
Methylfolate
(the active form on folate/B9)
(the folate and methionine cycles working efficiently)
What is SAMe formed from?
Methionine
What is transsulphuration?
Conversion of homocysteine to cystathionine
What is cystathionine?
A substrate for glutathione synthesis
Which gene is needed to convert homocysteine to cystathionine?
CBS
What processes are impacted with a SNP on the CBS gene?
Reduced conversion of homocysteine to cystathionine
Reduced SAMe
Faster conversion to ammonia (urea cycle)
How can a SNP on the CBS gene be supported?
Increase Zn, choline, TMG
Neutralise ammonia with reduced animal protein, and probiotics to reduce bacterial production
Limit sulphur containing foods e.g. eggs, onion
Which neurotransmitters is MTHFR essential for the synthesis of?
Serotonin
Dopamine
Adrenaline
Noradrenaline
Which gene is needed to break down serotonin, dopamine, adrenaline and noradrenaline?
COMT
Which hormone does COMT convert?
Active oestrogen to less active oestrogen
What process can be impacted by a SNP on the COMT gene?
Reduced conversion of active oestrogen to less active = increased risk of breast cancer etc
How can a SNP on the COMT gene be supported?
Choline, betaine, B9 and B12 rich foods (to support production of SAMe)
Avoid oestrogen disruptors e.g. plastics, anti-perspirants, dairy products
What is the eNOS gene responsible for?
Generating NO from arginine
What processes are impacted by a SNP on the eNOS gene?
Reduced eNOS activity and lower NO
What is the implication of reduced eNOS activity and lower NO?
Slower ammonia detoxification
Increase in free radicals
Increased CV disease risk
How can a SNP on the eNOS gene be supported?
Increase AO (rainbow foods)
Reduce intake of ammonia generating foods e.g. animal protein
Support NO production with beetroot juice or celery
