Here's my point though
Good sources of vitamin A are milk, eggs, liver, fortified cereals, darkly colored orange or green vegetables (such as carrots, sweet potatoes, pumpkin, and kale), and orange fruits such as cantaloupe, apricots, peaches, papayas, and mangos.
We "all know" carrots are good for vision. But no more so than lots of other foods are, many of which are more appetizing.
So why do we all know about carrots? Because of a government propaganda effort.
No, they didn't make up something out of whole cloth. The best propaganda is always close enough to the truth that people of good faith can at least take it seriously.
In this case, the point she was making was that scientists tried to isolate the nutrient in carrots that was good for vision, and they focused on beta carotene. And of course they were wrong, ha ha! It was the whole food that was effective.
Except that's not it either. Even the whole food isn't exceptionally good for vision. At best it can alleviate a deficiency that might cause problems. No study has suggested that vitamin A, or beta carotene, or whole carrots, actually improves vision for people who don't have any problems.
So if someone does have vitamin A deficiency, eating carrots can help. That fact doesn't make carrots the poster child for eating whole foods instead of the supplements the government would have you take instead.
The switch from butter to margarine ... cholesterol causes heart disease ... red meat will make you fat ... eat less meat and more grains ... Any one of these would be a better example.