Antibacterial Compound

A naturally occurring or added substance that can inhibit the growth of certain bacteria. Some foods, like honey, contain natural compounds studied for this property.

Antioxidant

A compound that helps neutralise unstable molecules called free radicals in the body. Antioxidants are found naturally in many fruits, vegetables, and plant-based foods.

Beta-Carotene

A plant pigment that gives many fruits and vegetables their orange or yellow colour. The body converts it into vitamin A.

Beta-Glucan

A type of soluble fiber found in foods like oats and barley, commonly studied for its role in supporting healthy cholesterol levels.

Casein

The main protein found in milk and dairy products, known for being digested more slowly than whey protein.

Circadian Rhythm

The body’s internal 24-hour clock, which influences sleep, digestion, and energy levels throughout the day and night.

Collagen

A structural protein found throughout the body, including in skin, joints, and connective tissue.

Cross-Contamination

When harmful bacteria or allergens transfer from one food or surface to another, often during preparation or storage.

Energy Density

A measure of how many calories a food contains relative to its weight or volume. Foods with high water and fiber content, like vegetables, tend to have low energy density — see our guide on high volume, low calorie foods for more on how this works in practice.

Fermentation

A process where bacteria, yeast, or other microorganisms break down sugars in food, often used to make products like yogurt, kefir, or sourdough. Our kefir vs yogurt guide looks at how fermentation time affects the final product.

Fiber

A type of carbohydrate the body can’t fully digest. It comes in soluble and insoluble forms and supports digestion — our guide on how much fiber you really need daily covers recommended amounts.

FODMAP

Short for fermentable carbohydrates that can trigger digestive discomfort in sensitive individuals. Our guide on high fiber, low FODMAP foods explains where fiber and FODMAP content overlap.

Foodborne Illness

Illness caused by consuming food contaminated with harmful bacteria, viruses, or toxins.

Gingivitis

Mild inflammation of the gums, often related to plaque buildup and oral hygiene habits.

Glycemic Index

A ranking of how quickly a carbohydrate-containing food raises blood sugar levels compared to a reference food.

Glycogen

The body’s stored form of carbohydrate, mainly kept in the muscles and liver, used as an energy source during physical activity.

Gut Microbiome

The community of bacteria and other microorganisms living in the digestive system, which plays a role in digestion and overall gut health.

Halitosis

The general term for persistent bad breath, which can have several dietary, oral, or digestive causes.

Lactose

The natural sugar found in milk and dairy products. Some people have difficulty digesting it, known as lactose intolerance — see our list of cheeses that are easier to digest.

Legume

A category of plants whose seeds grow in pods, including beans, lentils, and peas, generally known for their protein and fiber content. Several legumes show up in our guide to foods naturally high in iron.

Lutein and Zeaxanthin

Plant pigments found in leafy greens and colourful vegetables, commonly discussed in relation to eye health.

Macronutrient

The three main categories of nutrients the body needs in larger amounts: protein, carbohydrates, and fats.

MCT (Medium-Chain Triglycerides)

A type of fat found in some oils, including coconut oil, that’s processed by the body somewhat differently than longer-chain fats.

Micronutrient

Vitamins and minerals the body needs in smaller amounts, but which still play essential roles in overall health — our guide on vitamin D foods for vegetarians looks at one commonly under-consumed example.

Nutrient Density

A way of describing how many vitamins, minerals, and other beneficial compounds a food provides relative to its calorie content. Related to the idea behind our high volume, low calorie foods guide.

Oral Microbiome

The community of bacteria naturally present in the mouth, which plays a role in dental and gum health.

Pasteurization

A heat treatment process used to reduce harmful bacteria in foods like milk, making them safer to consume — see our fortified milk overview for related background.

Phytic Acid

A naturally occurring compound in grains and legumes that can reduce how well the body absorbs certain minerals. Fermentation and soaking can help reduce its effect.

Plaque

A sticky film of bacteria that forms on teeth, which can contribute to gum irritation if not regularly removed.

Polyphenol

A group of naturally occurring plant compounds, including catechins, associated with antioxidant activity and found in foods like tea, fruits, and vegetables.

Prebiotic

A type of fiber that serves as food for beneficial bacteria in the gut, rather than being digested directly by the body.

Probiotic

Live bacteria and yeasts found in certain foods, like yogurt and kefir, that are commonly associated with supporting gut health — our kefir vs yogurt guide compares two common sources.

Protein Synthesis

The biological process by which the body builds new proteins, including muscle tissue, often discussed in relation to exercise and recovery.

Saturated Fat

A type of fat that’s typically solid at room temperature, found in foods like butter, coconut oil, and fatty meats.

Sorbitol

A naturally occurring sugar alcohol found in some fruits, including dried apricots, that can affect digestion in larger amounts—our dried apricot nutrition guide covers this in more detail.

Trans Fat

A type of fat, often created through partial hydrogenation, generally considered best avoided due to its association with negative cardiovascular effects.

Ultra-Processed Food

Food products that have undergone extensive industrial processing and typically contain a longer list of additives than minimally processed foods.