Do you have a good study on the topic? In the fitness group I am a member, we do regular bloodwork and they have never seen such a thing in their 10 years of experience. On the contrary, most of the micronutrients/vitamins readings become (a lot) better after several months of the initial "uniform" diet. It includes all the veggies you can eat, though it's somewhat uniform and based on the season and market availability/price. Actually, in my first months being a member, I calculated that I received many thousands times more vitamins/minerals from food, compared to my previous years.

For example, I can eat more than half a kilo of kale in a day, over many days. This is like 20x the daily dose of vit K, 2.5x the daily dose of vit C, 1x the daily dose of vit A, etc. Then I'll rotate to kohlrabi for some time, then to cabbage, etc, etc.

Compared to my former pizza diet, this is insane. Indeed, thousands of times more micronutrients.