My mother in law always told us this, God bless her.
My Mother (RIP 5/2/11) was a big proponent of margarine in the 50s & 60s, but we kids wouldn’t eat it on anything. After 40yrs, both her neck carotid arteries clotted-up and she suffered 6 very minor TIAs, and they had to be surgically bypassed. We tried for years to wean her off that garbage, but she loved it, and I blame it partially for killing her.