I could not find any credible sources indicating that flax seeds (also known as linseed) loose significant nutritional benefits after been smashed, crushed or ground.

This article from Mayo Clinic in fact indicates that since the seeds tend to pass undigested, it is better to grind them:

Most nutrition experts recommend ground flaxseed because your body is better able to digest it. Whole flaxseed may pass through your intestine undigested, which means you won't get all the health benefits.

I could not find any credible sources indicating that flax seeds (also known as linseed) lose significant nutritional benefits after they've been smashed, crushed or ground.

This article from Mayo Clinic in fact indicates that since the seeds tend to pass undigested, it is better to grind them:

Most nutrition experts recommend ground flaxseed because your body is better able to digest it. Whole flaxseed may pass through your intestine undigested, which means you won't get all the health benefits.