Vegetable was very dull, typically comprising mainly some staple product made from rice, rye, barley, wheat, millet or maize. The addition of vegetable matter provided some variety to the diet. The staple diet of the Aztecs in Central America was maize and they cultivated tomatoes, avocados, beans, peppers, pumpkins, squashes, peanuts, and amaranth seeds to supplement their tortillas and porridge. In Peru, the Incas subsisted on maize in the lowlands and potatoes at higher altitudes. They also used seeds from quinoa, supplementing their diet with peppers, tomatoes, and avocados. In Ancient China, rice was the staple crop in the south and
Vegetable juice noted "a lack of human data and contradictory findings hampered conclusions". Another study has found that drinking vegetable juice reduces risks of Alzheimer's Disease by 76%. However, the British Nutrition Foundation holds that although vegetable juice counts as a serving, it can only count as one serving, regardless of the amount of juice drunk. Additionally, A 2007 Japanese study showed that although Japanese commercial juices had nutritional benefits, they were insufficient as a primary mode of vegetable consumption. Many popular vegetable juices, particularly ones with high tomato content, are high in sodium, and therefore consumption of them for health must