scored 91/100
Seaweed is a nutrient-dense marine vegetable exceptionally rich in iodine, minerals, and fiber, offering unique bioactive compounds that support thyroid function and metabolic health.
8.1 g net carbs after fiber.
Representative amounts for this food, not measured for this item. Real content varies widely by variety, ripeness and storage.
These are the scored components, not a sum: the published score also reflects normalisation across the catalog, so the parts above will not add to 91.
Less a 2.0 anti-nutrient penalty (high sodium).
Seaweed encompasses edible macroalgae species harvested from oceans worldwide, with origins in Asian cuisines spanning thousands of years. This food is nutritionally exceptional for longevity due to its extraordinary micronutrient density: it provides more bioavailable iodine per gram than virtually any other food source, critical for thyroid hormone synthesis and metabolic regulation. Seaweed delivers substantial amounts of magnesium (692mg/100g), potassium, and calcium—minerals essential for cardiovascular health, bone density, and nerve function. Its high fiber content (36.7g/100g) supports gut microbiota diversity and metabolic health. Seaweed also contains unique bioactive compounds including fucoidan (a sulfated polysaccharide) and fucoxanthin (a carotenoid), both documented in research for anti-inflammatory and potential metabolic benefits. The iron content is notably high, though plant-based iron requires adequate vitamin C for optimal absorption. One important consideration: seaweed's naturally elevated sodium and iodine levels require mindful consumption—excessive intake can stress thyroid function in iodine-sensitive individuals. Different varieties (nori, kombu, wakame, dulse) offer varied nutrient profiles, allowing strategic selection based on individual health goals.
Seaweed's exceptional iodine bioavailability enables adequate thyroid peroxidase function, which is essential for T3 and T4 synthesis. Proper thyroid function directly regulates basal metabolic rate and energy homeostasis critical for longevity.
Fucoidan and other polysaccharides in seaweed inhibit pro-inflammatory cytokine production and activate natural killer cells, while fucoxanthin and other carotenoids neutralize reactive oxygen species that accelerate aging.
High potassium (2944mg/100g) and magnesium content support vasodilation and reduce arterial stiffness; fucoxanthin may improve lipid profiles and endothelial function, key factors in cardiovascular longevity.
Seaweed's 36.7g/100g fiber—particularly soluble fibers and unique polysaccharides—selectively feed beneficial Bacteroides and Faecalibacterium species, reducing lipopolysaccharide translocation associated with aging-related inflammation.
Combined magnesium, calcium, and potassium work synergistically to reduce bone resorption; seaweed's alkalizing effect reduces urinary calcium loss, important for postmenopausal women and aging populations.
Consuming seaweed at midday optimizes mineral absorption when stomach acid and digestive secretions are peak; timing away from other iodine supplementation prevents excessive intake; allows full day of metabolic benefit without interfering with evening cortisol patterns
Breaks a fast
Seaweed is best consumed with meals containing fat and vitamin C for optimal micronutrient bioavailability. Individuals on thyroid medication should maintain consistent iodine intake and monitor TSH levels if adding seaweed regularly.
Per 100 g of the default form. Bars show how much higher or lower seaweed is than the average across 137 peer foods in this category. Green means a favorable direction; amber means the opposite.
Seaweed is classified as a vegetable. Seaweed is a nutrient-dense marine vegetable exceptionally rich in iodine, minerals, and fiber, offering unique bioactive compounds that support thyroid function and metabolic health.
Seaweed scores 91/100 in Formulate, making it an exceptional choice. Its strongest contributions come from Iron, Manganese, Sodium. The score blends nutrient density, fiber, healthy fats, protein quality, bioactive compounds, and glycemic impact.
Moderately — it contributes meaningful protein. A 85 g serving provides about 13 g of protein (~26% of the 50 g daily value).
Yes — it's a high-fiber food. A 85 g serving provides about 31.2 g of fiber (~111% of the 28 g daily value).
In a 85 g serving, seaweed is highest in Iron (~313% DV), Manganese (~217% DV), Sodium (~160% DV), Magnesium (~140% DV), Vitamin A (~138% DV).
Sometimes — it depends on your daily carb budget. A 85 g serving has about 8.1 g of net carbs (39.3 g total minus 31.2 g fiber).
Best in the midday. Consuming seaweed at midday optimizes mineral absorption when stomach acid and digestive secretions are peak; timing away from other iodine supplementation prevents excessive intake; allows full day of metabolic benefit without interfering with evening cortisol patterns
A typical serving is around 85 g (~220 kcal), based on the FDA's Reference Amount Customarily Consumed for this food category. There's no fixed daily target — most adults benefit from rotating seaweed alongside several other vegetable sources.
Seaweed pairs nicely with: Pair with citrus (lemon, orange) because vitamin C dramatically enhances non-heme iron absorption from seaweed, increasing bioavailability by up to 6-fold; Pair with fatty fish (salmon, mackerel) because fat-soluble carotenoids (fucoxanthin) require dietary lipids for intestinal absorption and transport to tissues; Pair with cruciferous vegetables (broccoli, kale) because both support detoxification pathways and provide sulfur compounds that optimize iodine metabolism; Pair with fermented foods (miso, tempeh) because pre-existing probiotics enhance polysaccharide fermentation and increase short-chain fatty acid production.
High sodium.
Encyclopedia entries that supply the same signature nutrients seaweed contributes. Click through to see clinical dose ranges, evidence quality, and bioavailable forms.
These are the nutrients seaweed contributes meaningfully toward (≥10% DV per 100 g serving). Click one to see what it does in the body, which supplements concentrate it, and which other foods are top sources.