Clams / Shellfish

No food on earth matches clams for vitamin B12 -- 100g of cooked clams delivers over 4,000% of your daily requirement in a single serving.

Why It Matters for Longevity

Vitamin B12 deficiency is quietly common, particularly among older adults (10-30% of those over 60 have impaired absorption) and anyone reducing animal products. Deficiency drives elevated homocysteine -- a well-established independent risk factor for cardiovascular disease, cognitive decline, and osteoporotic fractures. Clams solve this problem more efficiently than any supplement.

Beyond B12, shellfish are a concentrated source of heme iron (28 mg/100g, 155% DV), which is absorbed 2-3 times more efficiently than plant-based non-heme iron. They also deliver selenium (116% DV per 100g), a cofactor for glutathione peroxidase, one of the body's primary antioxidant defense enzymes. A systematic review (Watanabe et al., 2014) confirmed bivalve mollusks as the most bioavailable dietary source of B12, with absorption rates superior to synthetic supplements.

Shellfish consumption is inversely associated with cardiovascular disease risk (Rimm et al., 2018), likely through the combined action of omega-3 fatty acids, B12-mediated homocysteine reduction, and mineral cofactors for antioxidant enzymes. The calorie density is remarkably low -- roughly 148 kcal per 100g cooked -- making shellfish one of the most nutrient-dense foods per calorie available.

How to Use It

Steam clams in white wine and garlic (the Italian vongole method) to preserve nutrients. Canned clams retain most of their B12 content and are a practical option. Two servings per week is sufficient to maintain robust B12 status. Mussels and oysters offer similar benefits if clams are unavailable.

What to Pair It With

Flavor Profile

Briny and sweet with a pronounced umami depth and mineral undertone. The aroma is clean and oceanic with a faint iodine note. Texture ranges from tender to pleasantly chewy depending on species and cooking time. Overcooking turns them rubbery -- pull them the moment shells open.

The Science

• Cooked clams provide 98.9 mcg B12 per 100g, the highest of any food (USDA FoodData Central)
• Bivalve mollusks confirmed as most bioavailable dietary B12 source (Watanabe et al., 2014)
• Shellfish consumption inversely associated with cardiovascular disease risk (Rimm et al., 2018)
• B12 deficiency linked to elevated homocysteine, cognitive decline, and cardiovascular risk
• Heme iron from shellfish absorbed 2-3x more efficiently than plant non-heme iron

Key Nutrients