Because they did not, that's ridiculous. Just correlation. Their symptoms sound very similar to vasovagal syncope, which is a fairly regular occurrence in young healthy people that perhaps skip breakfast and then get their blood drawn / experience nausea / many other causes. They generally recover fine with no intervention other than some rest and getting a meal.
The article even says explicitly:
> While her symptoms are not directly linked to vitamin D deficiency
The article even says explicitly:
> While her symptoms are not directly linked to vitamin D deficiency