Vitamin A

50–90% of US adults are deficient in vitamin A; important for immune function and vision

Why It Matters for Longevity

50–90% of US adults are deficient in vitamin A; important for immune function and vision Essential for immune cell development, epithelial integrity, and vision (component of rhodopsin in retinal cells). Alzheimer's disease patients have lower levels of vitamin A; deficiency may contribute to Alzheimer's disease Vitamin A supports neurogenesis and has neuroprotective antioxidant effects; deficiency may accelerate brain aging. Systematic review (PMID 24849546) confirms Alzheimer's patients have significantly lower serum retinol and beta-carotene than controls, consistent with the book's claim (PubMed) Vitamin A (retinoic acid) activates RAR/RXR nuclear receptors (PMID 18400720) that regulate over 500 genes involved in immune function, cell differentiation, and apoptosis — longevity-relevant pathways (PubMed)

How to Use It

Pairs well with olive oil, salmon, sweet potato. Use as a nutrient in your daily meals according to the Longevity Diet guidelines.

What to Pair It With

Synergies

• Vitamin E (synergy): Both fat-soluble vitamins commonly deficient in US adults per the book; taken together in a multivitamin maximizes fat-soluble vitamin coverage - Vitamin D (synergy): Vitamin A and D share nuclear receptor partners (RXR); balanced intake of both optimizes immune regulation and gene expression - Olive Oil (synergy): Dietary fat is essential for absorption of fat-soluble vitamin A; olive oil is the Longevity Diet's primary fat vehicle

Flavor Profile

Category: micronutrient / supplement.

The Science

• PubMed: Systematic review (PMID 24849546) confirms Alzheimer's patients have significantly lower serum retinol and beta-carotene than controls, consistent with the book's claim - PubMed: Vitamin A (retinoic acid) activates RAR/RXR nuclear receptors (PMID 18400720) that regulate over 500 genes involved in immune function, cell differentiation, and apoptosis — longevity-relevant pathways - Examine.com: Preformed retinol (animal sources) is immediately bioavailable; beta-carotene from plants converts at variable rates (1–28%); combining both sources is recommended for adequate status - Book claim (high confidence): 50–90% of US adults are deficient in vitamin A; important for immune function and vision - Book claim (medium confidence): Alzheimer's disease patients have lower levels of vitamin A; deficiency may contribute to Alzheimer's disease

Key Nutrients