A dietary supplement is a manufactured product intended to supplement one’s diet by taking a pill, capsule, tablet, powder or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in order to increase the quantity of their consumption. The class of nutrient compounds includes vitamins, minerals, fiber, fatty acids and amino acids. Dietary supplements can also contain substances that have not been confirmed as being essential to life, but are marketed as having a beneficial biological effect, such as plant pigments or polyphenols. Animals can also be a source of supplement ingredients, such as collagen from chickens or fish for example. These are also sold individually and in combination, and may be combined with nutrient ingredients. In the United States and Canada, dietary supplements are considered a subset of foods, and are regulated accordingly.