Nutrition Lecture Notes: Carbohydrates, Lipids, and Proteins (Vocabulary)

Vocabulary flashcards covering key concepts from carbohydrates, lipids, and proteins in the nutrition notes.

Carbohydrates

The body's preferred energy source; composed of carbon, hydrogen, and oxygen (CHO); metabolized to ATP to provide energy for the body, especially the brain and nervous system.

CHO

Abbreviation for carbohydrates; literally carbon with water (carbon with H2O).

Monosaccharides

Single sugar units; include glucose, fructose, and galactose; all share the formula C6H12O6.

Glucose

Blood sugar; a primary monosaccharide found in fruits, vegetables, and sweeteners; major energy source for the body.

Fructose

The sweetest monosaccharide; occurs naturally in fruits and honey.

Galactose

A monosaccharide found primarily in milk and dairy products.

Disaccharides

Two monosaccharides joined together; examples include maltose, sucrose, and lactose.

Maltose

A disaccharide consisting of glucose + glucose; found in barley.

Sucrose

A disaccharide of fructose + glucose; common table sugar found in fruits and vegetables.

Lactose

A disaccharide of galactose + glucose; the main carbohydrate in milk.

Dehydration synthesis

The chemical process that joins two monosaccharides with the release of a water molecule.

High Fructose Corn Syrup (HFCS)

A sweetener made by converting corn starch to glucose, then some glucose to fructose; common HFCS forms include HFCS-42 and HFCS-55.

HFCS-42

A form of high fructose corn syrup with about 42% fructose.

HFCS-55

A form of high fructose corn syrup with about 55% fructose.

Polysaccharides

Many monosaccharides linked together; examples include starch, glycogen, and fiber.

Starch

The storage form of glucose in plants; found in grains, legumes, and root vegetables; includes amylose and amylopectin.

Amylose

A type of starch with a largely linear chain of glucose molecules.

Amylopectin

A highly branched form of starch.

Glycogen

The storage form of glucose in animals (including humans); stored in muscles and liver; not obtained from food.

Fiber

Structural components of plants that human enzymes cannot digest (cellulose).

Cellulose

A type of dietary fiber; the main structural component of plant cell walls.

Soluble fiber

Fibers that dissolve in water, form gels, and are fermented by colon bacteria; sources include oats, legumes, citrus, chia, and flax; can help lower blood glucose and may protect against diabetes.

Insoluble fiber

Fibers that do not dissolve in water; sources include whole grains, vegetables, and fruit skins; promote bowel movements and digestive health.

Lactose intolerance

Inability to digest lactose due to low lactase enzyme activity; lactose remains in the colon and is fermented by bacteria, causing gas, bloating, cramping, and diarrhea.

Lactase

Enzyme produced in the small intestine responsible for digesting lactose; activity is highest at birth and declines with age.

Lactase persistence

Genetically determined ability to digest lactose into adulthood; arose with dairy consumption in human history.

Lactose intolerance management

Dietary adjustments to tolerate lactose (e.g., limiting dairy, choosing lower-lactose options, lactase supplements, or dairy-free alternatives).

Dairy-free options

Non-dairy milks and products (soy, almond, rice, hemp milks) used to avoid lactose.

Lactase supplements

Lactase enzyme tablets or drops used to help digest lactose when consuming dairy.

Kefir and yogurt with live cultures

Fermented dairy products with live microbes that can improve lactose tolerance for some individuals.

Organic, grass-fed, raw milk

Alternative dairy options discussed for potential health considerations, though milk naturally contains hormones.

Lipid

Organic substances insoluble in water; the main types in nutrition are triglycerides, phospholipids, and sterols.

Triglycerides

Primary form of fat in foods and in the body's storage fat; consists of three fatty acids attached to glycerol.

Fatty acids

Organic acids with a carbon chain, a carboxyl (COOH) group at one end, and a methyl (CH3) group at the other; most have even numbers of carbons.

Chain length classification (fatty acids)

Short (4 carbons), medium (6–10 carbons), and long (12–24 carbons); shorter chains are softer at room temperature.

Saturated fatty acids

Fatty acids with the maximum number of hydrogen atoms (single bonds between carbons); typically solid at room temperature.

Monounsaturated fatty acids (MUFA)

Fatty acids with one double bond.

Polyunsaturated fatty acids (PUFA)

Fatty acids with two or more double bonds.

Essential fatty acids

Fats the body cannot synthesize; two types are alpha-linolenic acid (ALA, omega-3) and linoleic acid (LA, omega-6).

Omega-3 fatty acids

First double bond occurs after the third carbon from the methyl end; includes ALA, EPA, and DHA; EPA/DHA can be made from ALA and are also found in fatty fish.

Omega-6 fatty acids

First double bond occurs after the sixth carbon from the methyl end; includes linoleic acid (LA) and arachidonic acid (ARA); GLA is another omega-6.

ARA

Arachidonic acid, an omega-6 fatty acid.

GLA

Gamma-linolenic acid, an omega-6 fatty acid.

Trans fats

Fats with trans double bonds; natural trans fats occur in small amounts in ruminant animals; artificial trans fats are created by hydrogenation and are linked to negative health effects.

Hydrogenation

Process that converts liquid oils into solid fats by adding hydrogen, creating trans fats.

Partially hydrogenated oils

Processed fats often containing artificial trans fats; are a common source of trans fats in foods.

Health concerns of artificial trans fats

Linked to increased insulin resistance, higher LDL cholesterol, lower HDL cholesterol, inflammation, and vascular damage.

FDA and trans fats

The FDA banned artificial trans fats in 2018, though trace amounts may remain in some products.

Phospholipids

Lipids that are important in cell membranes and emulsification; they enable water and fat to mix; liver makes them, and they are found in foods like eggs and soy lecithin.

lecithin

A phospholipid found in foods (e.g., soy lecithin) used as an emulsifier.

Sterols

Sterols have a four-ring carbon structure; cholesterol is the most important sterol and is found only in animal products.

Cholesterol

A sterol essential for cell membranes, myelin sheaths, and synthesis of vitamin D, bile acids, and certain hormones; the liver produces most cholesterol, with some coming from the diet.

Proteins

Large, complex molecules that perform structural, enzymatic, transport, hormonal, immune, acid-base balance, and limited energy roles.

Amino acids

Organic compounds with a central carbon, hydrogen, an amino group (NH2), a carboxyl group (COOH), and a side chain (R); linked by peptide bonds to form proteins.

Essential amino acids

Nine amino acids that cannot be synthesized by the body and must be obtained from food: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine.

Nonessential amino acids

Eleven amino acids that can be synthesized by the body: alanine, arginine, asparagine, aspartate, cysteine, glutamate, glutamine, glycine, proline, serine, tyrosine.

Complete proteins

Proteins that contain all essential amino acids in adequate amounts (typically animal products).

Incomplete proteins

Proteins lacking one or more essential amino acids (typical of many plant foods).

Protein complementation

Combining different plant-based foods to provide all essential amino acids (e.g., rice and beans; peanut butter and whole grain bread).

Protein structure levels

Four levels: primary (amino acid sequence), secondary (folding patterns), tertiary (3D folding), and quaternary (multiple chains).