Multivitamin/Mineral Supplementation: Energy, Subjective Outcomes, and Biological Biomarkers

Primary Reference: Dodd FL, Kennedy DO, Stevenson EJ, Veasey RC, Walker K, Reed S, Jackson PA, Haskell-Ramsay CF.

Nutr Metab (Lond). 2020;17:16. doi:10.1186/s12986-020-00435-1. Open Access, Springer Nature.

1. Background and Scientific Rationale

The B vitamins — including thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folate (B9), and cobalamin (B12) — function as obligate cofactors in the citric acid cycle and mitochondrial electron transport chain, the principal pathways of cellular ATP synthesis. Deficiencies in these cofactors impair energy substrate oxidation, reduce ATP throughput, and produce downstream functional changes including fatigue, reduced cognitive performance, and diminished physical capacity. Coenzyme Q10 (CoQ10) serves as an essential electron carrier within the mitochondrial inner membrane and is similarly required for efficient oxidative phosphorylation.

Subclinical micronutrient insufficiency — tissue-level depletion insufficient to produce clinical deficiency disease but sufficient to impair enzymatic function — is prevalent in developed populations and is generally not detected by standard clinical laboratory panels, which are designed to identify frank deficiency rather than suboptimal status. Homocysteine, a sulfur-containing amino acid, accumulates when B6, folate, and B12 are insufficient to drive normal one-carbon metabolism and remethylation pathways. Elevated homocysteine is established as an independent cardiovascular risk marker and is associated with cognitive decline in older adults.

The Dodd et al. (2020) study was designed to test whether a multivitamin/mineral (MVM) supplement containing high-dose water-soluble B vitamins and CoQ10 would produce measurable changes in energy metabolism, physical performance, cognitive performance, and subjective fatigue in healthy adults under controlled exercise and cognitive demand conditions.

2. Study Methodology — Dodd et al. (2020)

2.1 Design

Randomized, double-blind, placebo-controlled, parallel groups trial. Pre-registered on ClinicalTrials.gov (NCT03003442). Conducted in accordance with the Declaration of Helsinki and approved by the Northumbria University Department of Psychology Ethics Committee. Published open-access in Nutrition & Metabolism, Springer Nature, 2020.

2.2 Participants

82 healthy adults, ages 18–35, physically active (minimum twice weekly exercise), non-smokers, BMI under 30, caffeine intake below 500 mg/day, not currently supplementing with vitamins or minerals. A subset of 35 participants provided blood samples for biomarker analysis. Power calculation confirmed adequate sample size for detection of primary outcomes at p < 0.05 with 80% power.

2.3 Intervention

Participants received either Supradyn — a commercially available multivitamin/mineral containing three times the recommended daily allowance (3x RDA) of water-soluble B vitamins plus CoQ10 — or a visually matched placebo, administered as one tablet daily for 28 days. Treatment allocation was computer-generated and double-blinded. Compliance was verified by treatment diary and pill count.

2.4 Assessment Protocol

Participants attended four laboratory visits. Visit 1 served as screening and cognitive task familiarization. Visit 2 established individualized treadmill speeds at each target exercise intensity. Visit 3 (Day 1) and Visit 4 (Day 28) were identical assessment sessions conducted after a 10-hour fast: a single dose was administered, followed by a 45-minute absorption window, then a 30-minute incremental treadmill run at increasing intensities (60–85% of VO2 max), followed by the cognitive demand battery. The 24-hour dietary intake prior to each assessment session was standardized.

2.5 Outcome Measures

Domain	Objective Measure	Subjective Measure
Energy Metabolism	Indirect calorimetry: energy expenditure (kcal/min), CHO oxidation (g/min), fat oxidation (g/min), VO2 uptake, RER	VAS: mental tiredness, physical tiredness, mental stamina, physical stamina, concentration
Exercise Performance	Treadmill run at 60–85% VO2 max, incremental stages	Ratings of Perceived Exertion (RPE), Borg 6–20 scale
Cognitive Performance	Computerized cognitive demand battery: serial 3s and 7s subtractions; Rapid Visual Information Processing (RVIP)	Stress ratings (visual analogue scale)
Blood Biomarkers (n=35 subset)	Ferritin, B12, homocysteine, creatinine, CRP, IL-6, protein carbonyls, F2-isoprostanes, glutathione peroxidase	—

Biomarker data were collected only in the 35-participant subset. Findings from that subset should be interpreted with appropriate caution given the limited sample size.

3. Results — Dodd et al. (2020)

3.1 Objective Findings — Energy Metabolism

Energy expenditure during the cognitive demand battery was significantly elevated in the MVM group relative to placebo across both Day 1 and Day 28 (p = 0.036, 0.044, and 0.035 for each of three repetitions). This effect was observed across both sexes. In male participants specifically, energy expenditure during incremental treadmill exercise was significantly higher in the MVM group at 10 minutes (p = 0.040), 20 minutes (p = 0.057, trend), and 30 minutes (p = 0.001) across both assessment days. Carbohydrate oxidation during exercise was also significantly elevated in males at 30 minutes (p = 0.015). The authors described this carbohydrate oxidation finding in males as novel — not previously demonstrated in the literature at the time of publication.

3.2 Subjective Findings — Tiredness, Perceived Exertion, and Stress

Measure	Finding	p-value
Mental tiredness — overall (Day 1)	Significantly lower in MVM group	p = 0.013
Mental tiredness — overall (Day 28)	Further reduction; greater effect than Day 1	p = 0.005
Mental tiredness — females, exercise	Lower at every time point: pre, 10, 20, 30 min	p = 0.001–0.036
Mental tiredness — males, exercise	Lower at 10 min of exercise	p = 0.049
Physical tiredness — females	Attenuated rise following 30 min exercise	p = 0.012
Ratings of Perceived Exertion	Lower in MVM group at 10 min exercise, both sexes; trend at 20 min	p = 0.030
Stress — females, cognitive tasks	Significantly reduced after each repetition	p = 0.002–0.046

The Day 1 to Day 28 trajectory for mental tiredness is a noteworthy finding. Effects were statistically significant on Day 1 — following a single dose — and were larger on Day 28. This pattern is consistent with cumulative micronutrient repletion over time and does not support the interpretation that effects require a full loading period before onset.

3.3 Biomarker Findings (n=35 Subset)

Blood samples were collected at rest, post-exercise, post-cognitive battery, and at 24 and 48 hours post-exercise. The following findings were observed in the biomarker subset:

• Ferritin was significantly higher in the MVM group on Day 28 compared to placebo (p = 0.03), confirming measurable tissue-level iron repletion by the four-week assessment point. Baseline iron status was not fully characterized; a number of female participants appeared to present with marginal iron insufficiency at enrollment.
• Homocysteine showed a non-significant downward trend in the MVM group. The authors attributed the lack of significance to the young, healthy participant population, which had relatively low baseline homocysteine levels with limited room for change.
• CRP, IL-6, protein carbonyls, F2-isoprostanes, and glutathione peroxidase showed no significant between-group differences. The authors noted that the healthy baseline status of participants and the nature of the exercise protocol may have limited the capacity to detect changes in inflammatory and oxidative stress markers.

The biomarker findings should be interpreted conservatively. The subset sample (n=35) was underpowered for most biomarker endpoints. Absence of significant findings does not establish absence of effect; it reflects the study’s limited power in that subgroup.

3.4 Blinding Verification

Treatment guess analysis confirmed blinding integrity. 62% of placebo participants and 73% of MVM participants believed they had received placebo — a non-significant difference (p = 0.267). Results were not attributable to expectation bias.

4. Strengths and Limitations — Dodd et al. (2020)

Strengths

• Randomized, double-blind, placebo-controlled design with confirmed blinding integrity.
• Pre-registered on ClinicalTrials.gov with pre-specified primary outcomes.
• Objective metabolic assessment via indirect calorimetry — laboratory-grade, not self-report.
• Both acute (Day 1) and chronic (Day 28) assessments conducted in the same participants, enabling within-subject temporal comparison.
• Both sexes included; sex analyzed as an independent variable.
• Blood biomarker collection in a subset, providing biological corroboration of subjective findings.

Limitations

• Participant pool was healthy, young (18–35), and physically active. Effects in older, less active, or nutritionally depleted populations are not established by this study and may differ in magnitude or character.
• Baseline nutritional status was not comprehensively characterized prior to randomization. The extent to which observed effects reflect deficiency correction versus pharmacological action in replete individuals cannot be determined.
• Biomarker subsample was small (n=35), limiting statistical power for most biological endpoints.
• Menstrual cycle phase was not controlled for in female participants, potentially introducing metabolic variability in that group.
• Cognitive outcomes were not pre-specified as primary endpoints and may have been underpowered.
• The supplement formulation (Supradyn 3x RDA + CoQ10) was a specific commercial product; generalizability to other formulations requires separate investigation.

5. Evidence from Biomarker-Based Multivitamin Research

The Dodd study represents one point in a broader body of literature that has measured blood-level biological outcomes following multivitamin/mineral supplementation. The studies below were selected for their use of objective biological endpoints, controlled designs, and relevance to nutrient repletion research. This section distinguishes between studies measuring blood nutrient status directly, those measuring downstream functional biomarkers, and those examining inflammatory and oxidative stress markers.

5.1 Isakov et al. (2018) — Multivitamin/Mineral/Phytonutrient Supplementation and Blood Nutrient Status

Study design: Randomized, double-blind, placebo-controlled, parallel groups trial. 120 healthy adults, ages 40–70, recruited in Russia. 56-day (8-week) intervention. (Nutrients 2018;10(2):120. doi:10.3390/nu10020120)

Biological measures: β-carotene, α-tocopherol, vitamin C, vitamin B6, vitamin B12, RBC folate, zinc, selenium measured at baseline, Day 28, and Day 56. Quercetin measured at baseline and Day 56. Homocysteine, hs-CRP, oxidized LDL, GGT, uric acid, and full lipid profile measured at baseline and Day 56.

Findings: Supplementation significantly increased circulating quercetin (p = 0.005), vitamin C (p = 0.001), RBC folate (p = 0.003), and partially prevented decline in vitamin B6 and B12 status. Serum homocysteine was significantly reduced (−3.97 ± 10.09 µmol/L) and GGT was significantly reduced (−1.68 ± 14.53 U/L) following 56 days of supplementation. hs-CRP, oxidized LDL, and lipid profile showed no significant changes.

Limitations: Baseline nutrient deficiency status was heterogeneous across this older adult population. The study population was from Russia, where dietary patterns and baseline micronutrient status may differ from Western populations. The absence of CRP change is consistent with a healthy population without significant baseline inflammation.

Relevance: Demonstrates that 8 weeks of multivitamin/mineral supplementation produces measurable blood-level changes in B vitamins, folate, and homocysteine in healthy adults aged 40–70. RBC folate is a more reliable indicator of tissue folate status than serum folate, and its significant increase confirms cellular-level repletion. The homocysteine reduction has clinical relevance given established associations between elevated homocysteine and cardiovascular and cognitive risk.

5.2 Harris, MacPherson & Pipingas (2015) — Blood Biomarkers Following 16-Week Multivitamin Supplementation in Older Adults

Study design: Randomized, double-blind, placebo-controlled trial. 116 healthy adults, ages 55–65 (68 women, 48 men), supplemented for 16 weeks with sex-specific formula multivitamins. Assessments at baseline and post-supplementation. (Nutrients 2015;7(5):3796–3812. doi:10.3390/nu7053796)

Biological measures: Pyridoxal 5′-phosphate (active B6), serum B12, RBC folate, serum homocysteine, hs-CRP, fibrinogen, plasma protein carbonyls, full lipid profile, kidney and liver function tests (AST, ALT).

Findings: Both groups showed significant increases in B6 and B12. In men: homocysteine was significantly reduced; total cholesterol and LDL were significantly reduced; protein carbonyls showed a marginal reduction trend (oxidative stress). In women: CRP was significantly reduced. Minor increases in ALT and AST remained within the clinical reference range and were considered non-significant. No cognitive improvements were detected on computerized tasks despite biomarker changes.

Limitations: Different formulas for men and women limit direct comparisons between sexes. No comprehensive baseline nutritional status assessment. Cognitive battery may have been insufficiently sensitive to detect subtle effects within the 16-week window in this age group.

Relevance: Provides direct evidence that multivitamin supplementation in adults over 55 produces significant and measurable changes in blood B vitamins, homocysteine, CRP, and oxidative stress markers. Biomarker improvements in the absence of detected cognitive changes illustrates the temporal dissociation between biological repletion and functional outcome measurement — a methodologically important observation for nutritional intervention design.

5.3 B Vitamin Supplementation and Homocysteine — Meta-Analytic Evidence

Evidence base: A meta-analysis of 19 randomized controlled trials (n = 47,921 participants) evaluating B vitamin supplementation on plasma homocysteine and cardiovascular outcomes found that B vitamin supplementation significantly reduced homocysteine levels across all included trials. A significant protective effect on stroke risk was observed; no significant effects on myocardial infarction, coronary heart disease, or all-cause mortality were detected. (Huang T et al. Clin Nutr. 2012;31(4):448–454.)

Biological mechanism: Homocysteine accumulates when one-carbon metabolism is impaired by insufficient B6, folate (B9), or B12. Supplementation with these vitamins restores remethylation and transsulfuration pathway activity, reducing circulating homocysteine. This is one of the more mechanistically well-established nutrient-biomarker relationships in nutritional biochemistry.

Relevance: Establishes homocysteine reduction as a consistent, replicable biological endpoint for B vitamin supplementation across large populations. Given that homocysteine is elevated in a substantial proportion of healthy middle-aged and older adults — particularly those with marginal B12 or folate status — its reduction represents a meaningful biological outcome in nutritional intervention research.

5.4 MultiVeg Study — Raschke et al. (2026): Biomarker Changes in Vegan Adults

Study design: Randomized, double-blind, placebo-controlled trial. 72 vegan adults, ages 19–57, Germany. 4-month multinutrient supplementation including B12, B2 (riboflavin), omega-3, vitamin D3, vitamin E, and choline. Biomarker assessment at baseline and 4 months. (Eur J Nutr. 2026. doi:10.1007/s00394-025-03814-7)

Biological measures: Serum vitamin B12, holotranscobalamin (active B12), flavin adenine dinucleotide (FAD, functional riboflavin), methylmalonic acid (MMA), homocysteine, folate, retinol-binding protein, β-carotene, choline, osteocalcin. The combined B12 status indicator (cB12) was calculated as a composite functional measure.

Findings: Significant between-group differences were observed for FAD (functional riboflavin), serum B12, holotranscobalamin, and the composite cB12 indicator. No significant differences were observed for MMA, homocysteine, folate, vitamin A markers, or choline.

Limitations: Population was specifically vegan, limiting generalizability to omnivorous populations. Baseline B12 deficiency was prevalent, making this more a deficiency-correction study than a subthreshold repletion study. MMA’s lack of change despite B12 increases may reflect the extended time required for functional cellular normalization.

Relevance: Demonstrates that holotranscobalamin and FAD — functional markers of active B12 and riboflavin, respectively — are sensitive to supplementation where serum measures alone may not fully capture cellular status. This underscores the importance of functional biomarker selection in nutritional research design.

6. What Was Not Measured

Across the Dodd study and the broader multivitamin trial literature, several biological measurements that would strengthen mechanistic interpretation and clinical applicability were not assessed. The following are factual observations about measurement gaps, not criticisms of individual study designs, which are often constrained by feasibility and cost.

6.1 Functional Intracellular Nutrient Status

Serum levels of vitamins and minerals reflect circulating transport pools and do not reliably indicate intracellular or tissue-level sufficiency. The following functional markers were generally absent from the reviewed studies: red blood cell (RBC) magnesium, which is a more reliable indicator of total body magnesium status than serum magnesium; RBC folate, which reflects tissue folate stores over a longer period than serum folate (included in Isakov et al. but not Dodd); methylmalonic acid (MMA), a functional marker of cellular B12 status that rises when B12-dependent enzymatic activity is impaired, even when serum B12 is within the normal range; and zinc-to-copper ratio, which is functionally relevant to antioxidant enzyme activity (copper-zinc superoxide dismutase) and immune function.

6.2 Mitochondrial and Cellular Energy Markers

No reviewed study directly measured mitochondrial function, ATP production capacity, or cellular respiratory chain activity. Indirect calorimetry in Dodd et al. provides a systemic-level proxy for metabolic fuel utilization but does not measure intracellular ATP throughput, mitochondrial membrane potential, or oxidative phosphorylation efficiency. Direct measurement of these parameters in peripheral blood mononuclear cells or skeletal muscle biopsies would provide more mechanistically precise evidence for B vitamin-driven mitochondrial effects.

6.3 Cardiovascular and Autonomic Measures

None of the reviewed studies assessed endothelial function (e.g., flow-mediated dilation), heart rate variability (HRV), or longitudinal blood pressure trends. These measures are relevant to the broader cardiovascular effects of B vitamin-mediated homocysteine reduction and CoQ10’s role in cardiac energy metabolism. Daily blood pressure and heart rate recording — as included in the Solprana pilot protocol — represents an observational advance on the static cardiovascular assessments used in most multivitamin trials.

6.4 One-Carbon Metabolism Pathway Markers

The methylation cycle depends on adequate B6, folate, B12, and riboflavin. Beyond homocysteine, markers such as S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and the SAM:SAH ratio provide a more complete picture of methylation capacity and are sensitive to marginal B vitamin insufficiency. These were not assessed in any of the reviewed studies.

6.5 Inflammatory Resolution Markers

The reviewed studies measured primary inflammatory markers (CRP, IL-6) but did not assess resolution-phase lipid mediators such as resolvins or protectins, which are derived from omega-3 fatty acids and play a role in the active downregulation of inflammation. Additionally, NLRP3 inflammasome activity and advanced glycation end-products (AGEs) were not evaluated. In healthy populations, CRP and IL-6 are typically at floor levels, which may explain the consistent absence of significant findings for these markers across studies enrolling non-inflammatory populations.

7. Methodological Implications for Future Nutritional Research

7.1 Baseline Nutrient Status as a Critical Variable

Across the reviewed studies, baseline nutritional status was generally not comprehensively characterized prior to randomization. This represents a significant methodological gap. The magnitude of biological response to micronutrient supplementation is directly related to the degree of preexisting insufficiency: individuals with marginal or deficient baseline status are expected to exhibit larger biological and functional responses than those with replete status. Failure to stratify by baseline status creates heterogeneous study populations in which responders and non-responders are pooled, attenuating observed mean effects and reducing statistical power.

Future study designs would benefit from pre-supplementation assessment of at minimum: serum B12, holotranscobalamin, RBC folate, MMA, pyridoxal 5′-phosphate (active B6), serum ferritin, 25-hydroxyvitamin D, serum magnesium, and plasma homocysteine. These measures collectively characterize the micronutrient status profile relevant to energy metabolism and cardiovascular function.

7.2 Responder versus Non-Responder Variability

Population-averaged results in nutritional intervention trials may conceal meaningful responder subgroups. Genetic polymorphisms affecting nutrient metabolism — most notably MTHFR C677T and A1298C, which impair folate metabolism and elevate homocysteine — create biologically distinct subpopulations with differing responses to standard supplementation. Individuals with MTHFR polymorphisms benefit specifically from methylfolate (5-MTHF) supplementation rather than folic acid, as they lack sufficient enzymatic capacity to convert the synthetic form. Stratification by relevant genetic markers would allow responder subgroup analysis and improve clinical applicability of findings.

7.3 Limitations of Averaging Heterogeneous Populations

The practice of reporting mean group differences in nutritional trials is statistically appropriate but can be clinically misleading when the population is biologically heterogeneous with respect to baseline status, age, sex, genetics, gut microbiome composition, and medication use. The Dodd study’s identification of sex-differentiated effects — with males showing greater objective metabolic changes and females showing greater subjective fatigue and stress reductions — illustrates this point at a gross level. Finer biological stratification would likely reveal additional sources of inter-individual variation. Study designs should pre-specify subgroup analyses based on clinically meaningful biological variables.

7.4 Integration of Subjective and Objective Outcomes

A consistent pattern in the reviewed literature is the detection of objective biomarker changes in the absence of corresponding functional or cognitive improvements, and the detection of subjective improvements in the absence of corresponding biomarker changes. These dissociations do not indicate measurement failure; they reflect the complexity of the relationship between cellular nutrient status, biological intermediate markers, and perceived functional outcomes. Study designs that combine subjective rating scales, objective metabolic or physiological measures, and blood biomarkers — across multiple time points — provide the most complete picture of supplementation effects and are best positioned to characterize the temporal sequence from biological repletion to functional change.

7.5 Assessment Duration and Temporal Resolution

Most reviewed studies assessed outcomes at a single post-supplementation time point. Studies assessing both acute (single-dose) and chronic effects, as in Dodd et al., provide substantially more information about the timeline of biological response. Nutrient tissue saturation follows kinetics specific to each compound: water-soluble vitamins generally achieve new steady states within 2–4 weeks, while fat-soluble vitamins and minerals may require longer. Daily or weekly data collection — particularly for physiological measures such as blood pressure and heart rate — captures response trajectories that single-endpoint designs cannot characterize.

8. Summary of Referenced Studies

Study	Design	n / Age	Biological Measures	Primary Biological Findings
Dodd et al. (2020)	RCT, DB, PC	82 / 18–35	Indirect calorimetry; ferritin, B12, Hcy, CRP, IL-6, oxidative stress (n=35 subset)	Ferritin ↑ (p=0.03); Hcy trend ↓; CRP/IL-6 NS; energy expenditure ↑ objectively
Isakov et al. (2018)	RCT, DB, PC	120 / 40–70	RBC folate, B6, B12, Hcy, hs-CRP, ox-LDL, GGT, lipid panel	RBC folate, vitamin C ↑ sig; Hcy ↓ sig (p<0.05); GGT ↓; CRP/LDL NS
Harris et al. (2015)	RCT, DB, PC	116 / 55–65	B6, B12, RBC folate, Hcy, CRP, fibrinogen, protein carbonyls, lipid panel	B6, B12 ↑ both sexes; Hcy ↓ in men; CRP ↓ in women; LDL ↓ in men
Huang et al. (2012)	Meta-analysis (19 RCTs)	47,921	Plasma homocysteine	B vitamins consistently reduce Hcy; stroke risk reduced; MI/CVD mortality NS
Raschke et al. (2026)	RCT, DB, PC	72 / 19–57	B12, holotranscobalamin, FAD, MMA, Hcy, folate, cB12 composite	Active B12, FAD ↑ sig; MMA and Hcy NS; importance of functional markers demonstrated

DB = double-blind; PC = placebo-controlled; RCT = randomized controlled trial; Hcy = homocysteine; NS = not significant; RBC = red blood cell; FAD = flavin adenine dinucleotide (functional riboflavin marker).

9. References

1. Dodd FL, Kennedy DO, Stevenson EJ, Veasey RC, Walker K, Reed S, Jackson PA, Haskell-Ramsay CF. Acute and chronic effects of multivitamin/mineral supplementation on objective and subjective energy measures. Nutr Metab (Lond). 2020;17:16. doi:10.1186/s12986-020-00435-1.

2. Isakov VA, Bogdanova AA, Bessonov VV, Sentsova TB, Tutelyan VA, Lin Y, Kazlova V, Hong J, Velliquette RA. Effects of multivitamin, multimineral and phytonutrient supplementation on nutrient status and biomarkers of heart health risk in a Russian population: a randomized, double blind, placebo controlled study. Nutrients. 2018;10(2):120. doi:10.3390/nu10020120.

3. Harris E, MacPherson H, Pipingas A. Improved blood biomarkers but no cognitive effects from 16 weeks of multivitamin supplementation in healthy older adults. Nutrients. 2015;7(5):3796–3812. doi:10.3390/nu7053796.

4. Huang T, Chen Y, Yang B, Yang J, Wahlqvist ML, Li D. Meta-analysis of B vitamin supplementation on plasma homocysteine, cardiovascular and all-cause mortality. Clin Nutr. 2012;31(4):448–454. doi:10.1016/j.clnu.2011.12.001.

5. Raschke S, et al. Assessment of vitamin B12, riboflavin, and related biomarker status following 4 months of multinutrient supplementation in healthy vegans: a randomised, double-blind, placebo-controlled trial. Eur J Nutr. 2026. doi:10.1007/s00394-025-03814-7.