A heart-healthy salmon is the number one, unbeatable choice for omega-3s. Halibut is another healthy option, as is cod. Buy thick fillets to give the veggies time to cook without drying out the fish.
Stir together 8 c (firmly packed) chopped spinach, 4 tsp olive oil, and ¼ tsp salt.
Tear 4 sheets of foil, each 14″ long. Place on a work surface.
Spoon one-quarter of spinach mixture on half of each sheet, leaving a margin of about 2″ on the 3 outer edges.
Add 2 teaspoons of the broth to each. Place a fish fillet on top. Sprinkle lightly with salt and black pepper.
Fold other halves of each sheet over fish. Fold over edges of long sides and flatten. Fold over twice more to seal. Repeat to seal other 2 edges of each foil packet.
Put packets in 1 layer on baking sheet and bake 18 minutes.
Cut tops of packets with knife (careful—steam burns), and spoon fish and spinach onto 4 plates.