A Plain-Language Glossary of Nutrition Terms

Macronutrients

The three main categories of nutrients — carbohydrates, proteins, and fats — that the body uses in relatively large amounts for energy and basic functions. They are the primary building blocks tracked on nutrition labels.

Micronutrients

Vitamins and minerals the body requires in smaller amounts but that are essential for a wide range of biological processes, including immune function, bone health, and energy metabolism.

Antioxidants

Compounds — including certain vitamins like C and E — that help neutralize unstable molecules called free radicals in the body. Many plant-based foods are described as rich sources of antioxidants.

Glycemic Index (GI)

A scale that estimates how quickly a carbohydrate-containing food raises blood glucose levels compared to a reference food, typically pure glucose. It ranges from 0 to 100; higher values indicate faster blood sugar spikes.

Dietary Fiber

A type of carbohydrate found in plant foods that the body cannot fully digest. It supports digestive health, contributes to a feeling of fullness, and is associated with a range of long-term health benefits in research literature.

Saturated Fat

A type of fat that is solid at room temperature and found primarily in animal-based foods and some tropical oils. Health guidelines in the U.S. generally recommend limiting saturated fat intake, though research on its role continues to evolve.

Trans Fat

An artificially produced fat created through a process called partial hydrogenation. Trans fats have been largely phased out of the U.S. food supply following regulatory action, but the term still appears on older labels or in imported products.

Sodium

A mineral and electrolyte found naturally in many foods and commonly added as salt during processing. It plays a role in fluid balance and nerve function; most nutrition guidance focuses on awareness of total daily intake.

Daily Value (%DV)

A reference number on U.S. nutrition labels showing how much of a nutrient a single serving contributes toward a general daily intake benchmark. It is based on a 2,000-calorie reference diet and is a tool for comparison, not a personal target.

Whole Grain

A grain that retains all three original parts of the kernel — the bran, germ, and endosperm. Refined grains have had the bran and germ removed, which strips out some fiber and nutrients.

Probiotics

Live microorganisms — often bacteria — found in certain fermented foods and supplements that, when consumed in adequate amounts, may support gut microbial balance. Research on their health effects is ongoing.

Omega-3 Fatty Acids

A category of polyunsaturated fats found in fatty fish, flaxseeds, walnuts, and other foods. They are considered essential because the human body cannot produce them in sufficient quantities on its own.