Seaweed
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.
Variants (2)
Nutrition · per ~85 g serving · ≈ ¾ cup chopped
- Riboflavin1.4 mg104% DV
- Vitamin B121.9 mcg80% DV
- Folate159.8 mcg40% DV
- Thiamin0.41 mg34% DV
- Vitamin E4.7 mg31% DV
- Vitamin C24.6 mg27% DV
- Niacin3.2 mg20% DV
- Vitamin A345.1 iu7% DV
- Iron56.4 mg313% DV
- Manganese5.0 mg217% DV
- Sodium3681.3 mg160% DV
- Magnesium588.2 mg140% DV
- Potassium2502.4 mg53% DV
- Copper0.40 mg44% DV
- Calcium254.2 mg20% DV
- Zinc2.2 mg20% DV
- Phosphorus221.0 mg18% DV
- Cholesterol28.1 mg
- Vitamin D2.6 iu
- Polyunsaturated Fat0.64 g
- Saturated Fat0.38 g
- Monounsaturated Fat0.09 g
- Carotenoids~5.1 mg
Score · 94/100
Vitamins & minerals packed in relative to calories — the single biggest driver of the score.
How much protein it delivers, by absolute grams and per calorie.
Dietary fiber for gut health, satiety and steadier blood sugar.
Fat quality — unsaturated vs saturated, and trans-fat free.
Polyphenols, flavonoids and other beneficial plant compounds for this food group.
Low sugar with a high fiber-to-carb ratio scores best — gentler on blood sugar.
- Iron369% DV
- Manganese256% DV
- Sodium188% DV
- Magnesium165% DV
- Riboflavin122% DV
Overview
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.
Health Benefits (5)
- Thyroid hormone support and metabolic optimizationstrongSeaweed'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.
- Anti-inflammatory and antioxidant protectionmoderateFucoidan 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.
- Cardiovascular disease risk reductionmoderateHigh 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.
- Gut microbiota diversity and metabolic endotoxemia reductionmoderateSeaweed'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.
- Bone mineral density preservationmoderateCombined 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.
Food Pairings
- ·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
Practical Tips
- ·Start with small portions (5-10g) and titrate upward to assess iodine tolerance; excessive seaweed consumption can suppress thyroid function in sensitive individuals
- ·Rinse dried seaweed briefly before use to reduce surface sodium while preserving iodine and minerals, or soak for 5 minutes if reducing sodium is priority
- ·Store dried seaweed in airtight containers away from light and humidity; most varieties maintain nutritional integrity for 6-12 months at room temperature
- ·Select organic or third-party tested varieties when possible, as seaweed bioaccumulates heavy metals from seawater; reputable suppliers test for cadmium and arsenic
- ·Consume seaweed varieties strategically: nori offers iodine and antioxidants; kombu provides maximum iodine and minerals; wakame balances nutrients; dulse offers iron with lower sodium
Optimal Timing
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
- · within 4 hours of thyroid medications
- · with calcium or iron supplements
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.
Systems supported
body systems this food feedsPathways supported
biochemical reactions enabled by this foodCompared to other vegetables
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.
What people ask about seaweed
What is seaweed?
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.
Is seaweed healthy?
Seaweed scores 94/100 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.
Is seaweed high in protein?
Moderately — it contributes meaningful protein. A 85 g serving provides about 13 g of protein (~26% of the 50 g daily value).
Is seaweed high in fiber?
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).
What vitamins and minerals are in seaweed?
In a 85 g serving, seaweed is highest in Iron (~313% DV), Manganese (~217% DV), Sodium (~160% DV), Magnesium (~140% DV), Riboflavin (~104% DV).
Is seaweed keto-friendly?
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).
When is the best time to eat seaweed?
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
How much seaweed should I eat?
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.
What pairs well with seaweed?
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.
Supplements that mirror Seaweed's nutrient profile
Encyclopedia entries that supply the same signature nutrients seaweed contributes. Click through to see clinical dose ranges, evidence quality, and bioavailable forms.
Signature nutrients in Seaweed
These are the nutrients seaweedcontributes 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.