Polymorphisms

Question 1

Single nucleotide polymorphisms (SNPs)

Answer 1

Differences in single bases in the sequence of a gene (a genetic variation in humans)

Each gene is identified by an rs (‘reference SNP’) number. e.g., rs1801133 is the MTHFR gene.

• Each SNP is further classified, by base change and position along from start of the gene e.g., rs1801133 C677T. C represents cytosine, changed to T (thymine) ― potentially changing the resulting amino acid and insufficient conversion of folate into methylfolate.
• Variants can be described as ‘wild type’ — usually ‘normal / stable’, ‘heterozygous’ — 1 chromosomal variant, usually indicating some potential change of function, or ‘homozygous’ — variants in both chromosomes, with greater change of function

Question 2

Nutrients (vitamin A)
Gene:

Answer 2

BCO1 gene (beta-carotene oxygenase 1) ― codes for the enzyme that converts beta-carotene to retinol.

Question 3

Nutrients (vitamin A)
SNPs

Answer 3

‒ BCO1 A379V TT alleles (= 32% reduction in enzyme activity).

‒ BCO1 R267S AT or TT plus BCO1 A379V CT or TT variant alleles (= 69% lower beta-carotene conversion)

Question 4

Nutrients (vitamin A)

Vitamin A deficiency symptoms

Answer 4

Impaired night vision, frequent infections, skin conditions (e.g., acne)

Question 5

Nutrients (vitamin A)

SNP recommendations

Answer 5

Increase preformed vitamin A from food (e.g., liver, fish oils) or supplements, especially if plant-based

Question 6

Nutrients (vitamin D):
Gene

Answer 6

VDR gene ― codes for the vitamin D receptor.

Question 7

Nutrients (vitamin D)
SNPs

Answer 7

At rs1544410, the A allele is associated with reduced bone density risk while the G allele is associated with a decreased risk of osteoporosis

Question 8

Nutrients (vitamin D)

Vitamin D deficiency symptoms:

Answer 8

Rickets and osteomalacia, osteoporosis, immune dysfunction (↑ infections, autoimmunity, allergies, asthma)

Question 9

Nutrients (vitamin D)

Recommendations

Answer 9

Ensure optimal vitamin D levels with regular testing, sun exposure, food sources (e.g., mushrooms, oily fish, eggs) and supplementation

Question 10

Nutrients (essential fatty acids):
Genes

Answer 10

Fatty acid desaturases are involved in EFA conversion. FADS 1 codes for Delta 5 Desaturase and FADS2 Delta 6 Desaturase

Question 11

Nutrients (essential fatty acids):
SNPs

Answer 11

There are complex relationships between SNPs and type of fat consumed. FADS1 rs174537 GG genotype may increase conversion of high dietary omega-6 to inflammatory AA, more so in African Americans. FADS2 rs174570 T allele is associated with lower GLA, AA, and EPA levels

Question 12

Nutrients (essential fatty acids):
Recommendations

Answer 12

EPA / DHA / ALA from fish oils / algae / flaxseed oils

Question 13

Inflammation
Gene

Answer 13

The TNF gene codes for the production of the pro-inflammatory cytokine (protein)

Question 14

Inflammation
SNP

Answer 14

At rs1800629 the A allele is associated with ↑ TNF and is associated with an ↑ risk of asthma, RA, psoriasis and cancer

Question 15

Inflammation
Recommendations

Answer 15

‒ Extra focus on ↓ pro-inflammatory foods (e.g., sugar, dairy, fried foods, high omega-6 foods), processed meats, alcohol.

‒ Increase anti-inflammatory foods / herbs ― turmeric, catechins (green tea), echinacea, omega-3 rich foods (‘SMASH’, flax).