Just because it looks like spinach doesn't mean you're getting it's full nutritional value — it's estimated that it takes 80 cups of spinach grown today to equal 1 cup grown 50 years ago. A Rutgers University study showed that it takes 19 ears of corn to have the same nutritional value of 1 ear of corn grown in 1940. The main culprit in this disturbing nutritional trend is soil depletion: Modern intensive agricultural methods have stripped increasing amounts of nutrients from the soil in which the food we eat grows.
Even if you're including vegetables and/or fruits as a large portion of your meals, how do you know you're actually getting vitamins and minerals from them?
Organically grown fruits and vegetables are definitely more nutrient dense, but they also don't approach their full nutritional value, especially if they're not locally grown. The vitamin C in broccoli breaks down a week after it's picked. In addition, all those antioxidants that fruits and vegetables supposedly have ~ antioxidants form in the final days when ripening occurs. But to have it be ripe in the stores, it has to be picked early, so you lose out on getting most of those nutrients. And so we start out with a mineral and trace mineral deficiency, and an antioxidant deficiency. So what do you do? Get to know where your food is from. Buy from farmers markets if you can, or buy organic if that's not available. Or make this the year you plant a veggie garden!