What is the difference? Navy beans are the only ones listed as an avoid for A blood types.

White:

http://www.dadamo.com/typebase4/depictor5.pl?451

Navy:

http://www.dadamo.com/typebase4/depictor5.pl?265

Great Northern:

http://www.dadamo.com/typebase4/depictor5.pl?268

The beans I've seen labelled as white beans are the same as the beans labelled northern beans.  Navy beans are clearly smaller, and have more flavor.

Yes, I bought a package of dried great northerns and in in small letters it said white beans.

I just cooked up a pack of Great Northerns this afternoon for Memorial day and seasoned them with kale, onion and chunks of goat (totally unplanned mix). I'm waiting to see if the scale moves downward a notch tomorrow morning, given the Northern's reputation for Diabetes prevention in A's.    

Even if it doesn't, I feel nice and full and wonder about how to make it into a
nice pate.

Quoted from TJ

The beans I've seen labelled as white beans are the same as the beans labelled northern beans.  Navy beans are clearly smaller, and have more flavor.

Interesting. In the stores near me, the ones labeled "small white beans" in one brand look identical to the ones labeled "navy beans" in another brand. I'm not quite sure exactly which kind it is if it's only labeled "white beans" so I don't buy them. I stick with the ones labeled "great northern beans" since they're beneficial or neutral for my whole family. If they said "white beans" in small print I wouldn't worry, since they're white and they're beans.

It's not that I only buy great northern beans; just that those are the only kinds of "white bean" I buy. I also get kidney beans for DS and black beans for us Os and lentils for those of us with SWAMI who can eat them.

Quoted from Seraffa

I just cooked up a pack of Great Northerns this afternoon for Memorial day and seasoned them with kale, onion and chunks of goat (totally unplanned mix). I'm waiting to see if the scale moves downward a notch tomorrow morning, given the Northern's reputation for Diabetes prevention in A's.    

Even if it doesn't, I feel nice and full and wonder about how to make it into a
nice pate.

I take  drained great northern beans, put them into a mini food processor, add about 1/4-1/3
cup of EVOO, two chopped garlic cloves, the juice of one lemon, a handful of chopped cilantro and sea salt to taste...Blend till smooth...Great for dipping with celery or carrot sticks...for
putting on top of rice cakes with some cultured vegetables...Or sometimes I "butter" my toast
with this spread and then add a few slices of turkey, soy cheese or rice cheese...
Delish!  

Thanks for all the replies, but what I'm asking is if anyone knows if there's a difference between them?

Cannellini beans are large and have that traditional kidney shape. With a slightly nutty taste and mild earthiness, they have a relatively thin skin and tender, creamy flesh. They hold their shape well and are one of the best white beans for salads and ragouts.

Great Northern beans are smaller than cannellinis and and suitable for any number of uses: salads, soups, stews, ragouts, purees. Their texture is slightly grainy, with a nutty, dense flavor. Popular in North America, Great Northerns look like white baby lima beans.

Navy beans are small and oval and cook relatively quickly (which, as Aliza Green notes in The Bean Bible, has made them popular with commercial baked bean manufacturers). Known as Boston beans, the white coco, pea beans or alubias chicas, Navy beans are perfect for dishes that don't need the full bean shape to shine: purees, soups, stews and baked beans.

It's great to know the differences between the three and it's worth paying more attention to them when you're using dried beans. Truthfully though, when we use canned white beans, we use these three almost interchangeably.

More info
http://www.wisegeek.com/what-are-white-beans.htm

I read somewhere online that a great northern bean is actually the inner seed of a mature green bean.

We also need to be careful which one we're buying when the similar beans have different values on BTD/GTD/SWAMI. For me and the other Os in the house, navy beans are an avoid while cannellini and great northern beans are beneficial or neutral. My B son can eat navy beans, but he can also eat the other two kinds of white beans, so I don't bother with navy beans at all.

If the package just says "white beans" I don't chance it.