NANP Board Practice Exam

Many fruits and vegetables such as onions, apples, and oranges, contain an energy promoting antioxidant called quercetin. To which category of phytonutrients does quercetin belong?

1. Carotenoids

2. Flavonoids

3. Isoflavones

4. Saponins

The correct answer is: Flavonoids

Quercetin is indeed classified as a flavonoid, which is a subclass of polyphenolic compounds. Flavonoids are a large group of phytochemicals that are known for their antioxidant properties, which can help to protect against cellular damage and promote overall health. This category of phytonutrients is particularly abundant in many fruits and vegetables, contributing to their vibrant colors and health benefits. The other categories mentioned, like carotenoids, isoflavones, and saponins, have different structures and functions. Carotenoids are primarily known for their role in photosynthesis and for providing colors such as orange and red in many fruits and vegetables. Isoflavones are a specific type of flavonoid typically found in soy products and certain legumes, known for their phytoestrogenic effects. Saponins are a different class of compounds that often contribute to the foaminess of certain food items and have been linked to various health benefits, but they do not share the same characteristics as quercetin. Thus, quercetin is best categorized under flavonoids.