Crab

Source of vitamin B12 (Alaska king crab: 8.6 mcg per 75 g cooked, 143% DV) and folate (Dungeness crab: 36 mcg per 3 oz, 9% DV). Recommended serving: 75 g (2½ oz) cooked.

Why It Matters for Longevity

Source of vitamin B12 (Alaska king crab: 8.6 mcg per 75 g cooked, 143% DV) and folate (Dungeness crab: 36 mcg per 3 oz, 9% DV). Recommended serving: 75 g (2½ oz) cooked. Shellfish providing exceptional vitamin B12 — a critical micronutrient for neurological function and homocysteine metabolism whose deficiency accelerates cognitive aging — alongside folate and zinc.. Vitamin B12 deficiency is prevalent in older adults (>10% in those over 60) and associated with elevated homocysteine, accelerated cognitive decline, and increased Alzheimer's risk; regular consumption of B12-rich shellfish like crab provides a highly bioavailable dietary source to prevent deficiency. (Moore et al., American Journal of Clinical Nutrition (2012) — PMID 22648721) Zinc (abundant in shellfish including crab) is essential for over 300 enzyme reactions and acts as a cofactor for antioxidant superoxide dismutase (Cu/Zn-SOD); age-related zinc deficiency impairs immune function and accelerates oxidative aging — supporting shellfish as a longevity food. (Ames (2006) — PMID 16636269)

How to Use It

Pairs well with lemon, garlic, extra-virgin olive oil. Use as a shellfish in your daily meals according to the Longevity Diet guidelines.

What to Pair It With

Ingredient	Why	Tradition
lemon	See synergies	General culinary
garlic	See synergies	General culinary
extra-virgin olive oil	See synergies	General culinary
parsley	See synergies	General culinary
ginger	See synergies	General culinary

Synergies

Lemon (synergy): Vitamin C from lemon enhances absorption of the non-heme iron present in crab; classic culinary combination is also nutritionally complementary. - Leafy-Greens (complement): Crab's B12 and folate work synergistically with green vegetable folate in the methionine cycle, reducing homocysteine — a key pathway the Longevity Diet targets for cognitive protection.

Flavor Profile

Taste: sweet, briny, rich, delicate. Aroma: fresh ocean, sweet shellfish, slightly sulfurous when cooked. Texture: tender flaky meat, firm when overcooked. Category: shellfish.

The Science

Moore et al., American Journal of Clinical Nutrition (2012) — PMID 22648721: Vitamin B12 deficiency is prevalent in older adults (>10% in those over 60) and associated with elevated homocysteine, accelerated cognitive decline, and increased Alzheimer's risk; regular consumption of B12-rich shellfish like crab provides a highly bioavailable dietary source to prevent deficiency. - Ames (2006) — PMID 16636269: Zinc (abundant in shellfish including crab) is essential for over 300 enzyme reactions and acts as a cofactor for antioxidant superoxide dismutase (Cu/Zn-SOD); age-related zinc deficiency impairs immune function and accelerates oxidative aging — supporting shellfish as a longevity food. - Fang et al., Food Chemistry (2017) — PMID 28108102: Crab shell-derived chitosan and crab meat bioactive peptides demonstrate antioxidant, anti-hypertensive, and anti-inflammatory properties in vitro; crab is also a notable source of astaxanthin (in red crab species), a potent carotenoid antioxidant. - Book claim (medium confidence): Source of vitamin B12 (Alaska king crab: 8.6 mcg per 75 g cooked, 143% DV) and folate (Dungeness crab: 36 mcg per 3 oz,

Key Nutrients

Nutrient	Per 100g	Notes
Vitamin B12		Highly bioavailable methylcobalamin form; absorbed via intrinsic factor in terminal ileum; passive absorption at pharmacological doses; critical for DNA methylation, myelin synthesis, and homocysteine clearance.
Zinc	~7.6 mg (cooked king crab)	Highly bioavailable; shellfish zinc is more bioavailable than plant-based zinc due to absence of phytate inhibitors; essential for immune function, testosterone production, and antioxidant enzyme activity.
Selenium	~36 mcg (cooked)	Organic selenocysteine form; ~90% bioavailability; cofactor for glutathione peroxidase; reduces thyroid cancer and cardiovascular disease risk at adequate dietary levels.