- BCO1 – encodes the BCO1 enzyme. Four common changes in BCO1 affect the activity of the enzyme and influence the availability of active vitamin A. Individuals that are slow converters (decreased BCO1 activity) are at risk of vitamin A deficiency, and it is important for these people to consume more animal-sourced vitamin A (retinol form).
- NBPF3 – encodes a protein of unknown function. A variation in NBPF3 increases the risk of vitamin B6 deficiency
- FUT2 – encodes part of a complex involved in host-microbe interactions. A variation in FUT2 distinguishes between “secretors” and “non-secretors”. Individuals with the “non-secretor” variant are protected from infection with H. pylori and are less likely to suffer from vitamin B12 deficiency.
- SLC23A1 – encodes a transporter that is important for maintaining healthy vitamin C levels. A variation in SLC23A1 reduces the absorption and distribution of vitamin C and increase the risk of deficiency.
- CYP2R1 – encodes an enzyme responsible for part of the conversion process of vitamin D into physiologically active calcitriol. Variants of CYP2R1 are associated with reduced enzyme activity and reduced levels of active vitamin D.
- GC – encodes a binding protein that is required to transport active vitamin D around the body and into the cells. Variations of GC reduce the efficiency of vitamin D transport and cellular uptake.
- APOA5 – encodes an apolipoprotein that helps control plasma triglyceride levels, high-density lipoprotein (HDL) maturation, cholesterol metabolism, and the transport of vitamin E into the cells. A genetic variant of APOA5 has been shown to influence vitamin E levels.
- MTHFD1 – encodes an important enzyme in the metabolism of folate, and variants in MTHFD1 have been linked to folate-related disorders.
- MTHFR – encodes an enzyme required for the activation of folate. Changes in MTHFR lead to lower levels of active folate circulating in the body.
- TMPRSS6 – encodes part of the signalling pathway that controls iron absorption from the diet and iron release from stores within the body. Variants in TMPRSS6 disrupt this pathway and can increase the risk of iron deficiency.
- TF – encodes transferrin, the transporter of iron around the body. One particular variant of TF is associated with increased transferrin but less efficient binding to iron, so less iron is transported around the body, increasing the risk of iron deficiency.
- NOS3 – encodes an enzyme required for the production of nitric oxide, a signalling molecule that plays a protective role in the cardiovascular system. A variant in NOS3 influences triglyceride levels and how effectively individuals respond to omega-3 supplementation.