B Vitamins
Deficiencies in B vitamins have been implicated in brain aging and dementias; Alzheimer's disease patients have lower levels of folate and vitamin B12.
Why It Matters for Longevity
Deficiencies in B vitamins have been implicated in brain aging and dementias; Alzheimer's disease patients have lower levels of folate and vitamin B12. B vitamins are essential for neuronal function, myelin sheath maintenance, and homocysteine metabolism; deficiency may accelerate brain degeneration by elevating homocysteine, a neurotoxic amino acid.. B vitamin supplementation was found largely ineffective for dementia prevention except in countries where food is not fortified with folate. In countries with mandatory folate fortification, baseline B-vitamin status is often adequate, so supplementation provides marginal additional benefit.. High-dose B-vitamin supplementation (folic acid, B6, B12) slowed brain atrophy rate by ~30% over 2 years in older adults with mild cognitive impairment and elevated homocysteine, suggesting a protective role against neurodegeneration. (Smith et al., PLoS ONE (2010) — PMID 20838622) B-vitamin treatment specifically reduced atrophy in brain regions most affected by Alzheimer's disease (medial temporal lobe), with greater benefit in those with higher baseline homocysteine, reinforcing the brain-aging connection. (Douaud et al., PNAS (2013) — PMID 23690582)
How to Use It
Pairs well with fortified cereal, legumes, leafy greens. Use as a nutrient in your daily meals according to the Longevity Diet guidelines.
What to Pair It With
| Ingredient | Why | Tradition |
|---|---|---|
| fortified cereal | See synergies | The Longevity Diet |
| legumes | See synergies | The Longevity Diet |
| leafy greens | See synergies | General nutrition |
Synergies
- Vitamin-D (complement): Both nutrients support neurological health; combined deficiency further increases dementia risk. - Omega-3 (synergy): Omega-3 fatty acids and B vitamins together more effectively slow brain atrophy than either alone, as shown in the VITACOG trial. - Leafy-Greens (complement): Dark leafy greens are among the richest dietary sources of folate, making them a key food vehicle for B9 intake.
Flavor Profile
Category: micronutrient.
The Science
- Smith et al., PLoS ONE (2010) — PMID 20838622: High-dose B-vitamin supplementation (folic acid, B6, B12) slowed brain atrophy rate by ~30% over 2 years in older adults with mild cognitive impairment and elevated homocysteine, suggesting a protective role against neurodegeneration. - Douaud et al., PNAS (2013) — PMID 23690582: B-vitamin treatment specifically reduced atrophy in brain regions most affected by Alzheimer's disease (medial temporal lobe), with greater benefit in those with higher baseline homocysteine, reinforcing the brain-aging connection. - Clarke et al., BMJ (2014) — PMID 25525286: Meta-analysis of 11 trials found that B-vitamin supplementation lowered homocysteine and significantly reduced stroke risk by ~7%, supporting cardiovascular longevity benefits beyond cognitive effects. - Book claim (medium confidence): Deficiencies in B vitamins have been implicated in brain aging and dementias; Alzheimer's disease patients have lower le - Book claim (medium confidence): B vitamin supplementation was found largely ineffective for dementia prevention except in countries where food is not fo
Key Nutrients
| Nutrient | Per 100g | Notes |
|---|---|---|
| Folate (B9) | Varies by food source; dark leafy greens ~194 mcg | Synthetic folic acid is ~85% bioavailable; food folate ~50%; absorption reduced by alcohol and some medications. |
| Vitamin B12 (cobalamin) | Clams ~98 mcg; fortified cereals ~6 mcg per serving | Requires intrinsic factor for absorption; bioavailability declines with age due to reduced gastric acid; vegans at high risk of deficiency. |
| Vitamin B6 (pyridoxine) | Chickpeas ~1.1 mg; salmon ~0.9 mg | Bioavailability from plant foods ~75% vs ~83% from animal foods; can be destroyed by heat processing. |