Soups
Tofu, Spirulina Seaweed & Fish-Head Soup
Traditionally used to nourish mother and baby during pregnancy
Why people make this soup
When you are pregnant, getting enough iodine matters — research has linked low iodine intake to impaired fetal brain development. Traditional Chinese food therapy has long turned to seaweed as a natural source of iodine, and spirulina seaweed in particular also brings calcium and folate into the pot. Paired with tofu for gentle, plant-based protein and a pan-seared fish head for sweetness and richness, this soup has been recommended in Cantonese households for generations to help nourish both mother and growing baby.
Who it suits / who should be cautious
- Well suited to: pregnant women, students facing heavy mental workloads, older adults, and those with a warmer constitution who enjoy light, nourishing soups.
- Seaweed is slightly cooling in nature; the ginger and fish head balance this, making the overall soup relatively neutral.
- Pregnant individuals with thyroid conditions should check with their doctor before consuming seaweed regularly, as iodine intake needs careful management in those cases.
Why these ingredients (the food-therapy logic)
- Spirulina seaweed (luo xuan hai zao): Traditionally considered to nourish and cool; contains iodine, calcium, folate, and alpha-linolenic acid, which are associated with healthy cholesterol balance and heart protection.
- Tofu (dou fu): Classically described as beneficial to the middle burner — gentle on the stomach, provides protein and calcium without being heavy.
- Fresh ginger (sheng jiang): Warms and harmonizes; counters the cooling nature of seaweed and helps settle the stomach during pregnancy.
- Fish head (yu tou): Rich in collagen and omega-3 fatty acids; pan-searing before simmering draws out a naturally sweet, milky broth.
Ingredients (3–4 bowls)
| Ingredient | Amount | Notes |
|---|---|---|
| Spirulina seaweed | 1 tablespoon | Rinse briefly before use |
| Firm tofu | 2 blocks | Cut into cubes |
| Fresh ginger | 2 slices | Lightly crushed |
| Large fish head | 1 (grass carp or bighead carp) | Cleaned; pan-sear before adding to pot |
| Water | 7 bowls (~1.75 L) |
Method
- Clean and dry the fish head. In a little oil, pan-fry both sides over medium heat until golden and fragrant.
- Give the tofu and spirulina seaweed a quick rinse.
- Add all ingredients — fish head, tofu, seaweed, and ginger — to a pot with 7 bowls of water.
- Bring to a boil, then reduce to a gentle simmer. Cook for 1 hour.
- Serve the soup along with the tofu and seaweed; eat as much of the solid ingredients as you like.
Bro Niu’s tips
This soup is naturally sweet and delicious — old and young alike enjoy it. If you cannot find spirulina seaweed, Japanese kombu (kun bu) or dried nori (zi cai) both work and are available at most Asian supermarkets. Regular consumption is traditionally associated with supporting memory and circulation. If you prefer to skip fish, lean pork is a fine substitute.
Community questions answered (selected)
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Q (Daisy): Is seaweed a cold ingredient? How many times a week is this soup suitable during pregnancy? Bro Niu: Seaweed is slightly cooling, but combined with ginger, fish head, and tofu the overall nature becomes quite moderate. Pregnant women tend to benefit from cooling and nourishing foods, so this soup is appropriate — about 1 to 2 times per week is fine.
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Q (Mandy): Can I use Japanese kombu instead of the spirulina seaweed? Bro Niu: Yes, Japanese kombu works perfectly.
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Q (namnam): Can I replace the fish with another protein? Bro Niu: Yes, lean pork works well as a substitute.
Published January 6, 2016 · Adapted and translated for Nourilo from a traditional home-kitchen recipe. Approx. 3 min read.
