A grain is a tiny, hard, dry seed extracted for human or animal use, with or without an associated hull or fruit covering. A grain crop is a plant that produces grains. Cereals and legumes are the two primary categories of commercial grain crops.
Dry grains, unlike other staple foods like starchy fruits and tubers, are more resilient once collected. Grains are highly adapted to industrial agriculture due to their resilience, as they can be mechanically harvested, transported by rail or ship, stored for extended periods in silos, processed for flour, or pressed for oil. Maize, rice, soybeans, wheat, and other grains have substantial global commodity markets, while tubers, vegetables, and other crops do not.
Many nutrients, including fiber, B vitamins (thiamin, riboflavin, niacin, and folate), and minerals, are found in grains (iron, magnesium, and selenium). People who consume whole grains as part of a balanced diet have a lower chance of developing certain chronic diseases.
Whole grains are unmilled and contain the complete grain kernel; milling produces a finer texture but eliminates fiber, iron, and B vitamins.