Maize contains the vitamin niacin, but not in a form the body can absorb.

For people in sub-Saharan Africa, where white corn is a staple food, substituting this biotech variety could help them meet their daily recommended intake of vitamin A and folate.

"One cup of broccoli has your daily intake of vitamin c," she said. Replace the nutritionally vacuous iceberg lettuce with baby spinach in tacos or mix sweet potatoes in your regular mashed potatoes.