Why it matters
Performance depends on both training and micronutrient availability . Genetics can modulate the levels, transport, or utilization of certain vitamins, and therefore, the response to training and supplementation . Personalized training based on genetics isn’t magic, but it does help prioritize what to measure and who to supplement.
1) Vitamin D: strength, power and injuries
Genes of interest:
- VDR (vitamin D receptor; e.g., FokI/rs2228570)
- GC (DBP transporter protein; rs2282679)
- CYP2R1 (25-hydroxylase; rs10741657)
What the evidence says (athletes):
- Vitamin D deficiency is very common in athletes, especially in winter, indoors, and at high latitudes. Recent reviews in elite athletes (including para-athletes) report high and seasonal prevalence. ( SpringerLink )
- Regarding strength/power , meta-analyses in athletes show negligible or small effects of supplementation when there is no marked deficiency, with signs of benefit in specific measures (e.g., quadriceps contraction) in updated analyses. ( PMC )
- Variants in CYP2R1, GC, and VDR are associated with differences in 25(OH)D and, in athletic cohorts, have been linked to performance level (CrossFit® Total) and a higher risk of insufficiency (VDR FokI). ( PubMed )
How to apply it
- Measure 25(OH)D in preseason and winter (general target: 30–40 ng/mL, adjusting to local clinical guidelines).
- Prioritize screening/supplementation in those with deficiency or who carry genotypes associated with low levels (e.g., GC rs2282679 G, CYP2R1 rs10741657 G, VDR rs2228570 G), and in indoor growers. ( PubMed )
- The dose should be individualized (it usually ranges between 1000–4000 IU/day depending on baseline levels and professional supervision).
2) B complex (B12, folate, riboflavin, B6): one-carbon metabolism and fatigue
Genes of interest:
- MTHFR (C677T/rs1801133): affects methylation and homocysteine .
- TCN2 (776C>G/rs1801198): B12 (holotranscobalamin) transport.
- FUT2 (rs601338): B12 absorption/status (via intrinsic factor and microbiota).
What the evidence says (key to resilience/recovery):
- MTHFR 677TT elevates homocysteine; in athletes, differences in Hcy and associations with cardiovascular performance have been observed. ( PMC )
- Riboflavin (B2) significantly reduces homocysteine in 677TT (clinical trial), and even modulates DNA methylation in this genotype (mechanism evidence). ( AHA Journal )
- TCN2 776C>G is associated with lower holoTC and worse B12 status; meta-analysis and cohort studies confirm this. ( ScienceDirect )
- FUT2 rs601338 influences serum vitamin B12 (associations replicated in humans), with a higher risk if intake is low or vegetarian. ( PMC )
- Regarding performance , there are RCTs with B complex that report improvements in endurance and reductions in lactate/ammonia in healthy subjects, although not specifically in elite athletes; even so, it suggests a benefit if there were subclinical deficiencies. ( PubMed )
How to apply it
- Measure B12 (holoTC or MMA), folate, and homocysteine in endurance athletes, vegetarians/vegans, and/or those with risk genotypes (MTHFR TT, TCN2 GG, non-secretory FUT2). ( PMC )
- If MTHFR 677TT : ensure riboflavin (1.3–1.6 mg/day; in TT, more may be required under supervision) and dietary folate; monitor Hc after 8–12 weeks. ( AHA Review )
- If B12 is low or TCN2/FUT2 is at risk : prioritize foods rich in B12 or supplementation (cyanocobalamin or methylcobalamin), with holoTC/MMA reassessment.
3) Vitamin A (retinol) and vision/recovery
Genes of interest:
- BCMO1/BCO1 (p. ej., rs7501331; rs12934922): conversión de β-caroteno a retinol .
What the evidence says:
- Variants in BCMO1 reduce the conversion of provitamin A to retinol and explain some of the interindividual variability in vitamin A status. ( Oxford Academic )
- Practical relevance: In sports with low light conditions (night vision) or with diets rich in carotenoids but low in retinol, these genotypes could favor a suboptimal state if preformed retinol is not consumed. (Evidence on direct performance: limited ; it is a plausible hypothesis of applied interest). ( SAGE Journals )
How to apply it
- If visual symptoms are present or a diet low in retinol (e.g., vegan), assess vitamin A status and consider preformed sources (dairy/eggs/prudent supplementation) in carriers of low-conversion variants .
Practical rules for a high-performing team
- Smart measurements, not blind ones
- Pre-season and mid-season: 25(OH)D, B12 (holoTC or MMA), folate, homocysteine .
- Repeat after 8–12 weeks if there was an intervention.
- When to consider genotyping (reduced panel):
- History of recurrent or indoor vitamin D deficiency → VDR/GC/CYP2R1 . ( SpringerLink )
- High homocysteine despite adequate diet → MTHFR (and assess riboflavin). ( AHA Review )
- Low or borderline B12 , vegetarian/vegan → FUT2 and TCN2 . ( PMC )
- Supplement with discretion
- Supplementation is beneficial if it corrects a deficiency or insufficiency ; otherwise, the effects on performance are modest and inconsistent. ( British Journal of Sports Medicine )
- Adjust dosage to baseline levels , season , sun exposure , diet and genotype when available.
Quick guide (vitamin-gene-action)
| Vitamin | Gen/es | Risk/effect | What to measure | Priority action |
| D | VDR, GC, CYP2R1 | Low levels, greater insufficiency; possible differences in strength and injuries | 25(OH)D | Strategically positioned solar exposure + D3 adjusted to levels. ( SpringerLink ) |
| B12/folato/B2 | MTHFR 677C>T | ↑ Homocysteine (TT special) | Hcy, folate, B12 (holoTC/MMA) | Ensure riboflavin and folate; reassess Hcy. ( AHA Review ) |
| B12 (transport) | TCN2 776C>G | ↓ HoloTC/estatus B12 | HoloTC/MMA | Increase intake/supplement B12 and monitor. ( ScienceDirect ) |
| B12 (absorption) | FUT2 rs601338 | ↓ Serum B12 (higher risk in vegans/low intake) | B12, holoTC/MMA | Dietary education + supplementation according to levels. ( PMC ) |
| A (retinol) | BCMO1 | ↓ Conversion of carotenoids to retinol | Serum retinol (if suspected) | Secure sources of preformed retinol if necessary. ( Oxford Academic ) |
Limitations and best practices
- Evidence in elite athletes regarding the “gene × vitamin × performance” relationship remains heterogeneous ; it prioritizes measuring and correcting deficiencies rather than genotyping the entire squad. ( British Journal of Sports Medicine )
- Genotyping complements, but does not replace , laboratory testing or dietary assessment.
- Avoid megadoses without indication; follow guidelines, review interactions and WADA lists for compound products.
Key bibliography:
- Vitamin D in athletes: prevalence and effect on strength/power.
Meta-analysis 2023–2024: Frontiers in Nutrition; update with quadriceps signal. ( PMC )
High prevalence in elite/para-sport. ( SpringerLink ) - Vitamin D (VDR/GC/CYP2R1) Genetics in Athletes:
A Review/Studies in Athletes and CrossFit®. ( PubMed ) - MTHFR and riboflavin (B2):
ACE: riboflavin ↓ homocysteine at 677TT; methylation RCT. ( AHA Journal ) - B12: TCN2 and FUT2
Meta-analysis/human studies on B12 transport/absorption and status. ( ScienceDirect ) - BCMO1 and vitamin A
variants that reduce the conversion of β-carotene to retinol. ( Oxford Academic )
- Date: 11/11/25
- Photo: Pixabay
- Note: The Nutrigenomics Institute is not responsible for the opinions expressed in this article.
