Cod with Noodles & Spinach
Cod pan-fried with Sriracha, spinach wilted in a wok with garlic and onion, whole wheat noodles stirred through. 552 calories and 35 grams of protein in fifteen minutes.
Researchers at Chalmers University tested exactly this amount of cod protein — 35 grams — and found it boosted iron absorption from plant foods by 2.7 times compared to eating those same foods without fish. This bowl pairs that cod with 196 grams of spinach and whole wheat noodles, both loaded with non-heme iron. The fish helps your body catch what the plants put on the plate.
Ingredients
- cod fillet (frozen) 1 fillet
- garlic 1 clove
- onion 0.5
- noodles, whole wheat 3 ounces
- Sriracha sauce 1 teaspoon
- olive oil 1 tablespoon
- spinach 7 ounces
Method
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Defrost the fish according to the instructions.
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Slice the garlic and cut the onion into thin wedges.
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Cook the noodles according to the package instructions.
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Rub the fish with salt and half of the Sriracha. Heat half of the oil in a frying pan and cook the cod fillet for 6–8 minutes, turning it after 3 minutes, until browned and just cooked through.
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Heat the remaining oil in a wok and gently stir-fry the onion, garlic and the rest of the Sriracha until softened. Add the spinach a handful at a time, allowing it to wilt while stirring.
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Stir the noodles into the spinach and season with a bit of salt, if needed.
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Serve the fish with the spicy spinach and noodles.
Add that splash of soy sauce from the recipe suggestion. A clinical trial found that traditionally fermented soy sauce tripled non-heme iron absorption from a grain-based meal. The fermentation creates compounds called Shoyu polysaccharides that keep iron soluble in your gut, stacking with the cod protein’s own iron-boosting effect on the spinach and noodles.
Worried about spinach oxalates locking away the iron? A study in 13 women tested this directly with stable iron isotopes. Adding potassium oxalate to a meal had zero effect on iron absorption. The researchers found that spinach’s slightly lower absorption compared to kale came from its calcium and polyphenol content, not oxalates.
Chalmers University of Technology, 2022 · DOIWhy This Works
Behind this recipe
Does frozen cod have the same iron-boosting effect as fresh?
The iron-absorption enhancement comes from cod’s muscle protein, specifically the cysteine-containing peptides that form during digestion. Freezing preserves muscle protein structure. The Chalmers study extracted its cod protein from frozen Atlantic cod co-products, so the effect was demonstrated with frozen fish. Your frozen fillet works.
Can I use a different fish instead of cod?
The mechanism behind the iron boost is called the meat-fish-poultry factor. It works through muscle protein peptides, not something unique to cod. The Chalmers study tested cod specifically, but earlier research by Hurrell et al. showed that extracted heme-free beef protein enhanced iron absorption to the same extent as whole muscle tissue. Any fish with a similar muscle protein profile should work. The key is that the protein source is animal muscle, not plant-based.
Why add the spinach a handful at a time?
Spinach loses about 90% of its volume when it wilts. Adding 196 grams all at once would overflow the wok and cool it down too fast, steaming the leaves instead of stir-frying them. Handful by handful keeps the wok hot so each batch wilts quickly in the oil, which also means better contact between the olive oil and the spinach’s fat-soluble carotenoids.
Is the Sriracha doing anything beyond adding heat?
Capsaicin, the compound that makes Sriracha spicy, has been shown in research to increase beta-carotene levels by 44% through enhanced bile secretion and changes in intestinal absorption surface area. In this recipe, the Sriracha is stir-fried directly with the spinach in Step 5, so the capsaicin and the spinach’s beta-carotene enter the gut together.
