NHM 454 - Final Exam

Modules 4, 5, & 6

Why is dietary fiber considered a functional food?

Because it provides health benefits beyond basic nutrition by resisting digestion in the upper GI tract and being fermented into bioactive compounds in the colon.

What are the three major short-chain fatty acids (SCFAs)?

• Acetate

• Propionate

• Butyrate

Which SCFA is the primary energy source for colonocytes?

Butyrate

Name four major functions of SCFAs.

• Fuel colon cells

• Anti-inflammatory effects

• Lower colon pH

• Improve gut barrier integrity

What happens to dietary fiber in the colon?

Gut microbes ferment it into SCFAs, which nourish beneficial bacteria and influence immune and metabolic health.

Besides producing SCFAs, what else can fiber bind?

• Bile acids

• Cholesterol

• Estrogen

• Heavy metals

• Toxic metabolites

Why does soluble fiber lower LDL cholesterol?

It binds bile acids, increasing their excretion, forcing the liver to use cholesterol to make new bile acids.

What is the difference between soluble and insoluble fiber?

Soluble:

• Fermentable

• Produces SCFAs

• Forms gel

• Lowers cholesterol

Insoluble:

• Adds stool bulk

• Speeds GI transit

• Less fermentable

What is resistant starch?

Starch resistant to digestion in the small intestine that is fermented in the colon into SCFAs.

Why are resistant starches beneficial?

• Lower glycemic response

• Increase SCFA production

• Improve gut health

What does FODMAP stand for?

Fermentable
Oligosaccharides
Disaccharides
Monosaccharides
And
Polyols

Why are FODMAPs restricted in IBS?

They are poorly absorbed, highly fermentable carbohydrates that increase gas and water in the intestine, worsening IBS symptoms.

What is oxidation?

Loss of electrons, hydrogen, or gain of oxygen.

What is reduction?

Gain of electrons, hydrogen, or loss of oxygen.

What is a free radical?

An atom or molecule with an unpaired electron that is highly reactive.

What are reactive oxygen species (ROS)?

Oxygen-containing reactive molecules that can damage lipids, proteins, and DNA when produced in excess.

What is oxidative stress?

When ROS production exceeds antioxidant defenses.

Name three endogenous antioxidant enzymes.

• Superoxide dismutase (SOD)

• Catalase

• Glutathione peroxidase (GPx)

Name four sources of endogenous ROS.

• Mitochondria

• Peroxisomes

• Cytochrome P450

• Phagocytic immune cells

Name three exogenous ROS sources.

• Smoking

• UV radiation

• Pollution/drugs

List four consequences of oxidative stress.

• DNA damage

• LDL oxidation

• Inflammation

• Endothelial dysfunction

Primary antioxidants do what?

Donate hydrogen/electrons to stop free radical chain reactions.

Secondary antioxidants do what?

Regenerate primary antioxidants and chelate metals.

Tertiary antioxidants do what?

Repair or remove oxidatively damaged molecules.

Why do whole foods often outperform isolated antioxidant supplements?

Antioxidants work synergistically within the food matrix and alongside endogenous antioxidant systems.

Define a functional food.

A whole, fortified, enriched, or enhanced food that provides health benefits beyond basic nutrition when consumed regularly.

What is NOT considered a functional food?

Pills or dietary supplements.

Define dietary supplement.

A pill, capsule, tablet, or liquid intended to supplement the diet but not replace food.

What is the food matrix?

The complex interaction of nutrients and non-nutrients within whole foods that affects bioavailability and bioactivity.

What did the 6-A-Day Study demonstrate?

Whole fruits and vegetables reduced oxidative stress more effectively than vitamin/mineral supplements containing the same nutrients.

What is the goal of organic agriculture?

Produce food while minimizing harm to ecosystems, animals, and humans.

Organic farming limits the use of what?

• Synthetic pesticides

• Synthetic fertilizers

Organic livestock cannot receive what?

• Growth hormones

• Routine antibiotics

USDA labeling: What does "100% Organic" mean?

Every ingredient is certified organic.

USDA labeling: What does "Organic" mean?

At least 95% organic ingredients.

USDA labeling: What does "Made with Organic" mean?

At least 70% organic ingredients.

Why might organic plants contain more phytochemicals?

Greater environmental stress stimulates production of protective secondary metabolites.

IBS Study (Soy isoflavones & Vitamin D): What was the study design?

Randomized clinical trial.

IBS Study (Soy isoflavones & Vitamin D): What is the intervention/independent variables?

• Soy isoflavones

• Cholecalciferol (Vitamin D)

IBS Study (Soy isoflavones & Vitamin D): What are the dependent variables?

• Inflammatory markers

• Gut permeability

• Antioxidant capacity

IBS Study (Soy isoflavones & Vitamin D): What are the main findings'?

Reduced:

• Inflammation

• Gut permeability

No improvement:

• Antioxidant capacity

IBS Study (Soy isoflavones & Vitamin D): Why is reducing gut permeability important?

It strengthens intestinal barrier function and may reduce IBS symptoms.

Maternal Vitamin A study: What question was this study asking?

Does maternal vitamin A intake influence vitamin A stores in offspring?

Maternal Vitamin A study: Which organ stores the most vitamin A?

Liver

Maternal Vitamin A study: What was the study design?

Controlled animal experiment using rats.

Maternal Vitamin A study: What was the independent variable?

Maternal vitamin A intake level.

Three treatment groups:

• Low vitamin A

• Medium vitamin A

• Adequate vitamin A

Maternal Vitamin A study: Low maternal vitamin A caused what?

• Poor pup growth

• Reduced organ growth

• Lower vitamin A stores

Maternal Vitamin A study: What were the dependent variables?

• Vitamin A concentration in offspring tissues

• Growth of pups

• Organ weights

• Maternal vitamin A stores

Maternal Vitamin A study: What were the main findings?

• Greater vitamin A accumulation in offspring tissues

• Better growth and organ development

EGCG & Lactobacillus Fermentum study: What is a synbiotic?

A combination of probiotics and compounds that enhance their function (traditionally probiotics + prebiotics; this study evaluated probiotic plus phytochemical synergy).

EGCG & Lactobacillus Fermentum study: What was the study design?

Controlled animal study in aging mice.

EGCG & Lactobacillus Fermentum study: What is the intervention/independent variables?

• EGCG supplementation

• Lactobacillus fermentum supplementation

Researchers evaluated them together as a synbiotic intervention.

EGCG & Lactobacillus Fermentum study:

• Immune function

• Cellular immune responses

• Antioxidant capacity

• Indicators of aging-related health

EGCG & Lactobacillus Fermentum study: What are the main findings?

• Improved immune responses

• Increased antioxidant capacity

• Benefits observed across generations

EGCG & Oral Cancer study: What was EGCG's effect on normal vs cancer cells?

Selective pro-oxidant activity:

• Killed cancer cells

• Spared normal cells

EGCG & Oral Cancer study: What was the study design?

Laboratory cell culture study (in vitro).

EGCG & Oral Cancer study: What was the independent variable?

Exposure to EGCG ((−)-epigallocatechin-3-gallate).

EGCG & Oral Cancer study: What were the dependent variables?

• Oxidative stress levels

• Cell survival

• Cell death

• SIRT3 signaling activity

EGCG & Oral Cancer study: What signaling pathway was involved?

SIRT3 signaling.

EGCG & Oral Cancer study: Why is this important?

It suggests EGCG may selectively induce oxidative stress in cancer cells while protecting healthy cells.

EGCG & Oral Cancer study: What were the main findings?

EGCG exerted pro-oxidative effects in cancer cells while having less damaging effects in normal cells.