This Levitas Academy paper provides a comprehensive review of the mechanisms and
biochemical pathways through which B vitamins contribute to cellular function, metabolic health,
and disease prevention. Each B vitamin is examined in terms of its physiological roles,
pathways of action, and influence on aging and chronic disease. The paper explores their
distinct roles in one-carbon metabolism, DNA repair, mitochondrial function, immune modulation,
and neural health, emphasizing how adequate intake supports longevity and mitigates risks of
age-related illnesses.
1. Vitamin B1 (Thiamine)
Pathways of Function: Thiamine acts as a cofactor for enzymes in the pentose
phosphate pathway and the tricarboxylic acid (TCA) cycle, particularly for pyruvate
dehydrogenase, which converts pyruvate to acetyl-CoA. This process is critical in ATP
production for high-energy-demanding tissues, such as the brain and muscles.
Neurological Impact: Thiamine deficiency disrupts ATP synthesis, leading to neuronal
death and conditions like Wernicke-Korsakoff syndrome. The vitamin’s role in
neuroprotection highlights its importance for cognitive health and longevity (Selhub,
2000).
2. Vitamin B2 (Riboflavin)
Electron Transport Chain (ETC): Riboflavin is integral to cellular energy production, as it
forms FAD and FMN, cofactors essential for electron transfer in mitochondrial oxidative
phosphorylation. These coenzymes enable the reduction and oxidation reactions that
produce ATP, directly influencing cellular energy levels and antioxidant capacity.
Antioxidant and Homocysteine Management: Riboflavin also aids in glutathione
recycling, a powerful cellular antioxidant. Through its role in homocysteine metabolism, it
helps maintain vascular health and prevent oxidative damage in tissues (Gruber, 2016).
3. Vitamin B3 (Niacin)
NAD+ Pathway: Niacin is essential for NAD+ synthesis, a cofactor in over 500 enzymatic
reactions, including DNA repair and sirtuin activation. Sirtuins, particularly SIRT1, are
critical for cellular repair and longevity, modulating gene expression to enhance
mitochondrial function and metabolic resilience under oxidative stress.
Neurodegeneration Prevention: Studies show that increasing NAD+ via B3
supplementation may protect against neurodegeneration by stabilizing mitochondrial membranes, particularly in age-related diseases such as glaucoma (Williams et al.,
2017).
4. Vitamin B5 (Pantothenic Acid)
Coenzyme A (CoA) Synthesis: B5 is a precursor for CoA, a cofactor involved in fatty
acid synthesis and beta-oxidation within mitochondria. CoA is vital for the formation of
acetyl-CoA, enabling energy production and synthesis of steroid hormones.
Stress Adaptation: By supporting adrenal hormone synthesis, B5 plays a critical role in
cortisol production, helping the body manage stress. Its influence on CoA pathways thus
supports both metabolic and endocrine resilience (Depeint et al., 2006).
5. Vitamin B6 (Pyridoxine)
Amino Acid Metabolism and Neurotransmitter Synthesis: B6 is crucial for
transamination and decarboxylation reactions in amino acid metabolism. It acts as a
cofactor for enzymes producing neurotransmitters like serotonin, dopamine, and GABA,
thus influencing mood regulation and cognitive function.
Anti-inflammatory Pathways: Pyridoxine modulates the kynurenine pathway, reducing
neurotoxic intermediates and supporting immune homeostasis. It also impacts the
sphingosine-1-phosphate pathway, which influences inflammatory response, playing a
role in cardiovascular and cancer prevention (Ueland et al., 2017).
6. Vitamin B7 (Biotin)
Gene Regulation and Metabolic Roles: Biotin functions as a cofactor for carboxylases
involved in gluconeogenesis, fatty acid synthesis, and amino acid metabolism. It also
regulates gene expression by modifying histones, impacting DNA structure and function.
Support for Skin, Hair, and Nail Health: Its influence on keratin infrastructure promotes
skin, hair, and nail health. Biotin deficiency is rare but can lead to dermatological issues,
underscoring its role in maintaining cellular structural integrity (Fenech, 2017).
7. Vitamin B9 (Folate)
One-Carbon Metabolism: Folate, converted into tetrahydrofolate (THF), is essential for
transferring one-carbon units in DNA synthesis and repair, especially in thymidine and
purine production. This role is vital for cellular proliferation and genome stability.
Epigenetic Influence: Folate’s involvement in methylation is significant for gene
expression and epigenetic regulation, impacting neurodevelopment and reducing
homocysteine levels to protect cardiovascular health (Porter et al., 2016).
8. Vitamin B12 (Cobalamin)
Methylation and Myelin Formation: B12 is crucial for methylation, acting as a
coenzyme for methionine synthase, which converts homocysteine to methionine.
Methionine is further converted to S-adenosylmethionine (SAM), a universal methyl donor
crucial for DNA methylation, neurotransmitter synthesis, and myelin formation.
Neuroprotection and Hematological Health: B12 is essential in protecting neural health
and supporting erythropoiesis (red blood cell formation), mitigating risks of
neurodegenerative diseases and anemia. Low B12 is linked to increased homocysteine
levels and cognitive decline (Lyon et al., 2020).
Conclusion
B vitamins perform diverse and interlinked roles in biochemical pathways essential for cellular
function, metabolism, and disease prevention. Their involvement in one-carbon metabolism,
oxidative phosphorylation, neurotransmitter synthesis, and anti-inflammatory pathways provides
comprehensive support for physiological resilience, particularly in aging. Ensuring optimal intake
of each B vitamin can significantly influence longevity, immune resilience, and the prevention of
age-related diseases.
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