Looks like you have all the info you need on the difference (i.e., we don't really eat yams in this country but two types of sweet potatoes - the orange ones are marketed as "yams"). I prefer the orange variety but because they're quite a bit moister than the white sweet potatoes you might want to do further research before using them interchangably in baking or pastas/gnocchi, etc. -- I just don't know.
I looked on the Dole 5-A-Day website, here's how they break out the nutrional stats. Very surprising to me, as I would have thought the yam had more vitamin A, but check out the numbers!
For one half cup, cooked:
weight: 100g calories: 76 Fiber 2.5g Vit A: 15740 Vit C: 13 Potas: 230 Folate: 6
weight: 68g calories: 79 Fiber: 2.7 Vit A: 83 Vit C: 8 Potas: 456 Folate: 11
Hope that helps!
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