Nutrients Worth Knowing: A Quick-Reference Glossary

Antioxidants

Compounds that neutralize unstable molecules called free radicals, which can damage cells over time. Found naturally in many fruits, vegetables, and whole grains. Vitamins C and E, as well as beta-carotene, are well-known examples.

Electrolytes

Minerals — primarily sodium, potassium, magnesium, and calcium — that carry an electrical charge and help regulate fluid balance, nerve signaling, and muscle function. They are lost through sweat and must be replenished through food and fluids.

Probiotics

Live microorganisms that, when consumed in adequate amounts, may confer a health benefit on the host. They are found in fermented foods like yogurt, kefir, and sauerkraut, and are associated with supporting gut microbiome balance.

Omega-3 Fatty Acids

A family of polyunsaturated fats essential to human health that the body cannot produce on its own. The main dietary forms are ALA (from plants like flaxseed), and EPA and DHA (from fatty fish and algae). Research consistently associates adequate intake with cardiovascular and brain health.

Macronutrients

The three major nutrient categories — carbohydrates, proteins, and fats — that provide the body with energy (measured in calories). All three are needed in relatively large quantities compared to micronutrients.

Micronutrients

Vitamins and minerals required by the body in small amounts to support growth, metabolism, and overall health. Unlike macronutrients, they provide no calories but are critical for hundreds of biological processes.

Dietary Fiber

The indigestible portion of plant foods that passes through the digestive system largely intact. Soluble fiber dissolves in water and may help lower blood cholesterol and glucose levels; insoluble fiber adds bulk to stool and supports digestive regularity.

Glycemic Index (GI)

A scale from 0 to 100 that ranks how quickly a carbohydrate-containing food raises blood glucose levels compared to pure glucose. High-GI foods cause rapid spikes; low-GI foods produce a slower, more gradual rise.

Prebiotics

Non-digestible food components — primarily specific types of fiber — that selectively feed beneficial bacteria in the gut. Common sources include onions, garlic, bananas, and oats.

Phytonutrients

Naturally occurring compounds produced by plants that may support human health, though most are not classified as essential nutrients. Examples include flavonoids in berries and lycopene in tomatoes.

Bioavailability

The proportion of a nutrient that is actually absorbed and used by the body. A food can be rich in a nutrient on paper but have low bioavailability due to the form it is in or what it is eaten alongside.

Daily Value (DV)

A reference amount set by the U.S. Food and Drug Administration (FDA) used on Nutrition Facts labels to indicate how much of a nutrient a serving of food contributes relative to a general daily target. Based on a 2,000-calorie diet.