Are tinned marrowfat peas good for you?
Mostly, yes, with one real gap. Marrowfat peas are peas left to mature and dry in the field rather than picked young and green, which is why they cook up starchy and floury, and why they are what mushy peas are made from.
Against frozen garden peas, per 100 g:
| Tinned marrowfat, drained | Frozen garden peas, boiled | |
|---|---|---|
| Protein | 6.9 g | 5.5 g |
| Fibre | 5.0 g | 5.5 g |
| Vitamin C | trace | 12 mg |
| Sodium | 160 mg | 4 mg |
| Energy | 87 kcal | 70 kcal |
Source: CoFID 2021, codes 13-562 and 13-536.
Protein and fibre: as good as frozen peas. Slightly more protein, about the same fibre. 100 g gives a sixth of the 30 g of fibre a day the NHS recommends.
Vitamin C: effectively none. Drying and canning take it out, where freezing keeps most of it. On a long-life diet vitamin C is the gap that actually matters, so do not count these as your green vegetable. See vitamins and a long-life diet.
Salt: a little. 160 mg of sodium is about 0.4 g of salt. The NHS calls a food low in salt at 0.3 g per 100 g or less, and high above 1.5 g, so they sit at the low end of the middle: nothing like tinned meat, but more than a pea from the freezer.
The short version: good protein and fibre for a tin, a little salt, no vitamin C.
Cooking with them
Simmered for a while they break down into a thick, savoury purée without any help, which makes them a soup base as much as a vegetable. Heated briefly they hold their shape. They take mint, vinegar, butter and smoked or salty meat particularly well, which is the logic behind ham and pea soup and marrowfat pea fritters.