One of the first things that a low real income produces is malnutrition.

Here are some of the world's most nutrient-dense foods:

Salmon, Kale, Seaweed, Garlic, Shellfish, Potatoes, Liver, Sardines, Blueberries, Egg Yolks, Dark Chocolate

https://www.healthline.com/nutrition/11-most-nutrient-dense-foods-on-the-planet