Nutrition Basics Quiz

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Questions and Answers

What is the recommended daily intake percentage of carbohydrates for maintaining a balanced diet?

  • 10–20%
  • 45–65% (correct)
  • 70–80%
  • 25–35%

Which type of carbohydrates should be prioritized in a diet?

  • Refined sugars
  • Artificial sweeteners
  • Simple carbohydrates
  • Complex carbohydrates (correct)

What is a common dietary source of saturated fats?

  • Fish
  • Coconut (correct)
  • Avocados
  • Olive oil

Which of the following fatty acids is an omega-3 fatty acid that the liver cannot synthesize?

<p>Linolenic acid (B)</p> Signup and view all the answers

What role does the liver play in cholesterol levels in the body?

<p>It synthesizes about 85% of blood cholesterol. (B)</p> Signup and view all the answers

What is the primary role of vitamins in the body?

<p>To facilitate the use of macronutrients. (A)</p> Signup and view all the answers

Which vitamin can be synthesized in the body instead of requiring external intake?

<p>Vitamin D (D)</p> Signup and view all the answers

What distinguishes water-soluble vitamins from fat-soluble vitamins?

<p>Water-soluble vitamins are absorbed with water and not stored significantly. (D)</p> Signup and view all the answers

Which of the following statements about antioxidants is true?

<p>Vitamins A, C, and E function as antioxidants by neutralizing free radicals. (D)</p> Signup and view all the answers

What is a consequence of excessive intake of fat-soluble vitamins?

<p>It can cause health problems due to their ability to be stored in the body. (B)</p> Signup and view all the answers

Which vitamin is primarily associated with coenzyme functions in amino acid metabolism?

<p>Vitamin B6 (C)</p> Signup and view all the answers

What is the primary source of Vitamin B9?

<p>Green vegetables and legumes (B)</p> Signup and view all the answers

Which vitamin deficiency can lead to symptoms such as irritability, convulsions, and anemia?

<p>Vitamin B6 (C)</p> Signup and view all the answers

Which vitamin is known for its role in collagen synthesis?

<p>Vitamin C (B)</p> Signup and view all the answers

What is a common symptom of biotin (Vitamin B7) deficiency?

<p>Scaly skin inflammation (A)</p> Signup and view all the answers

Which vitamin can mask a deficiency of Vitamin B12?

<p>Vitamin B9 (D)</p> Signup and view all the answers

What type of foods primarily provide Vitamin B12?

<p>Meats, eggs, and dairy products (D)</p> Signup and view all the answers

What deficiency is characterized by symptoms such as gastrointestinal upset and delayed wound healing?

<p>Vitamin C (C)</p> Signup and view all the answers

What is the desirable total cholesterol level for adults, measured in mg/dl of blood?

<p>200 mg/dl or lower (C)</p> Signup and view all the answers

What is a significant consequence of high LDL levels (≥160 mg/dl)?

<p>Cholesterol deposits in artery walls (B)</p> Signup and view all the answers

Which dietary fatty acids are associated with increasing blood cholesterol levels?

<p>Trans fats (D)</p> Signup and view all the answers

How does the liver regulate cholesterol production in relation to dietary intake?

<p>It has a basal production rate regardless of dietary intake (D)</p> Signup and view all the answers

What recent finding has emerged regarding HDL levels and cardiovascular disease?

<p>High HDL levels do not consistently protect against CV disease (D)</p> Signup and view all the answers

What effect do unsaturated omega-3 fatty acids have on platelets?

<p>They prevent spontaneous clotting. (A)</p> Signup and view all the answers

Which body shape is associated with higher levels of cholesterol and LDLs?

<p>Apple shape (B)</p> Signup and view all the answers

Which lifestyle factor is known to lower HDL levels?

<p>Cigarette smoking (A)</p> Signup and view all the answers

What is now believed to be a more accurate indicator of the need for treatment in cardiovascular disease?

<p>Non-HDL cholesterol levels (D)</p> Signup and view all the answers

What medication is commonly prescribed to lower LDL cholesterol levels?

<p>Statins (B)</p> Signup and view all the answers

What primarily occurs during the fed state after eating?

<p>Nutrients are stored and ATP synthesis is predominant. (B)</p> Signup and view all the answers

Which of the following is the major fuel for ATP synthesis during the fed state?

<p>Glucose (A)</p> Signup and view all the answers

How are monosaccharides like fructose and galactose processed after absorption?

<p>They are converted to glucose in the liver. (A)</p> Signup and view all the answers

What happens to excess dietary nutrients regardless of their source during the fed state?

<p>They are transformed to fat. (D)</p> Signup and view all the answers

Where is glycogen primarily stored in the body during the fed state?

<p>Liver and muscle tissue (C)</p> Signup and view all the answers

What is the role of very low-density lipoproteins (VLDLs) in the fed state?

<p>To package fats with proteins for transport. (B)</p> Signup and view all the answers

During the fed state, how does glucose enter the cells?

<p>It requires insulin for cell uptake. (B)</p> Signup and view all the answers

Which of the following statements is true about dietary amino acids in the fed state?

<p>They are used to remake degraded body proteins. (C)</p> Signup and view all the answers

Flashcards

Carbohydrate Dietary Requirement

45-65% of daily caloric intake, primarily from complex carbs (whole grains, vegetables) rather than simple sugars.

Simple Carbohydrates vs. Complex Carbs

Complex carbohydrates are preferred over simple carbohydrates (monosaccharides and disaccharides) in a healthy diet. Complex carbs are found in whole grains and vegetables.

Dietary Carbohydrates and Obesity

Large amounts of refined sugars increase risk of obesity and nutritional deficiencies because they provide "empty calories".

Carb Intake and Low-Income Groups

In low-income groups, carbohydrates often make up a larger portion of the diet due to cost compared to higher protein foods.

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Lipid Sources

Lipids, mainly triglycerides, come from saturated fats (meat, dairy), trans fats (hydrogenated oils), and unsaturated fats(seeds, nuts, vegetable oils).

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Essential Fatty Acids

Linoleic acid (omega-6) and linolenic acid (omega-3) are essential fatty acids that the body cannot produce and must obtain from the diet.

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Cholesterol Sources

Cholesterol is found in animal products like egg yolks, meats, organ meats, shellfish, and dairy, although the liver produces most of it.

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Vitamin B6 (pyridoxine)

A vitamin crucial for amino acid metabolism, a coenzyme in many reactions.

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Vitamin B7 (Biotin)

Coenzyme supporting fat, glycogen, and amino acid synthesis.

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Vitamin B9 (Folic Acid)

A coenzyme involved in nucleic acid and amino acid metabolism.

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Vitamin B12

Required for nucleic acid metabolism and red blood cell production.

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Vitamin C (Ascorbic Acid)

An antioxidant and crucial for collagen synthesis for healthy tissue.

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NAD⁺ and NADP⁺

Important coenzymes involved in many biochemical reactions.

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Oxidative Deamination

The process by which amino acids are converted into keto acids during energy production.

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Keto Acid Modification

The transformation of keto acids from amino acid oxidation into usable forms for energy production.

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Fed State

The period after eating when nutrients enter the bloodstream and are stored.

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Anabolism

The process of building up body tissues and storing nutrients.

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Catabolism

The process of breaking down tissues to provide energy.

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Glucose

The main energy source during the fed state.

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Glycogen

A storage form of glucose in the liver and muscles.

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VLDL

Very Low-Density Lipoproteins, which transport fat from the liver to other parts of the body.

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Vitamins

Organic compounds needed in small amounts for bodily functions, crucial for using energy from macronutrients, primarily carbs, protein, and fat.

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Coenzyme

A compound that works with an enzyme to start a chemical reaction.

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Water-soluble vitamins

Vitamins (B complex and C) dissolved in water absorbed with water/not stored in the body and excreted in urine

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Fat-soluble vitamins

Vitamins (A, D, E, and K) dissolved in fat absorbed with lipids/stored in the body, excess can be harmful.

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Vitamin D

Made in the skin when exposed to sunlight.

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Free radicals

Molecules with unpaired electrons that damage cells.

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Antioxidant vitamins

Vitamins (A, C, E) along with Selenium protect against cell damages caused by free radicals.

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Vitamin B12 absorption

Requires intrinsic factor for proper absorption from the stomach.

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Balanced Diet

A diet that includes a variety of foods from all major food groups in appropriate quantity to meet the nutritional needs of the body.

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Desirable Total Cholesterol Level

Less than 200 mg/dL for adults.

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High LDL Cholesterol

Levels 160 mg/dL or higher are considered bad, linked to artery-clogging deposits.

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High HDL Cholesterol

Traditionally viewed as good because it carries cholesterol for removal, but recent research is unclear.

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Liver Cholesterol Production

The liver makes cholesterol naturally, regardless of diet.

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Dietary Saturated Fats and Cholesterol

Saturated fats promote cholesterol production and hinder its removal from the body.

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Dietary Unsaturated Fats and Cholesterol

Unsaturated fats encourage cholesterol excretion and conversion to bile salts.

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Trans Fats and Cholesterol

Trans fats significantly raise LDL and lower HDL, the worst effect on cholesterol levels.

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Cholesterol and CVD

High total cholesterol is linked to atherosclerosis, a major risk for cardiovascular disease.

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Omega-3 Fatty Acids

Unsaturated fats, often found in cold-water fish, that can help prevent blood clots and lower blood pressure by reducing platelet stickiness.

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HDL Levels & Smoking

Cigarette smoking tends to decrease High-Density Lipoprotein (HDL) levels, a crucial type of cholesterol.

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Exercise & Estrogens on Cholesterol

Regular aerobic exercise and estrogens can lower Low-Density Lipoprotein (LDL) and increase HDL, contributing to better cholesterol management.

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Body Shape & Cholesterol

Body shape, specifically 'apples' (upper body fat) and 'pears' (lower body fat) , can influence cholesterol and LDL levels differently.

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Non-HDL Cholesterol

A newer measure of cholesterol that considers various cholesterol types and often is a more accurate predictor of heart disease risk, especially better than just total cholesterol/HDL.

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Statins & Cholesterol

Statins are drugs that help lower LDL cholesterol, widely used to treat high cholesterol and prevent cardiovascular disease.

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Cholesterol & Heart Disease Risk

While high cholesterol and LDL/HDL ratios were previously considered prime risk factors for heart disease, assessment of other factors and more accurate indicators of heart disease risk exist.

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Study Notes

Chapter 24: Nutrition, Metabolism, and Energy Balance

  • Video: Why This Matters (Career Connection)
    • Understanding body's nutrient conversion to energy helps advise patients on diets for peak performance.

Part 1 - Nutrients

  • Nutrient: substance in food needed for growth, maintenance, and repair.

  • Five categories.

  • Three macronutrients form most of our diet: carbohydrates, lipids, and proteins.

  • Two micronutrients (vitamins and minerals) are important but needed in smaller amounts.

  • Most nutrients act as metabolic fuel, some build molecules and cells.

  • Water accounts for ~60% of food volume.

  • ~40 molecules are essential nutrients.

  • Cells (especially liver cells) have the ability to convert one type of molecule to another, adapting to varied food intakes.

  • Energy value: measured in kilocalories (kcal).

    • One kcal raises 1 kg of water by 1°C.
    • 1 kcal = one Calorie (C).
    • Carbohydrates and proteins have 4 kcal/g, lipids have almost 9 kcal/g.
  • USDA's MyPlate: guidelines represented as portions on a dinner plate.

    • Includes fruits, vegetables, grains, protein, and dairy.
  • Basic dietary principles:

    • Eat only what is needed.
    • Eat plenty of fruits, vegetables, and whole grains.
    • Avoid junk food,

Part 2 - Metabolism

  • Metabolism: sum of all biochemical reactions in the body involving nutrients.
    • Substances are constantly built (anabolism) and broken down (catabolism).
    • Even at rest, the body uses energy for essential activities like breathing and nutrient absorption.

24.3 Metabolism as the Sum of Biochemical Reactions in the Body

  • Anabolism: reactions that build larger molecules/structures from smaller ones.
    • Example: protein synthesis from amino acids.
  • Catabolism: reactions that break down complex structures into simpler ones.
    • Example: protein hydrolysis to amino acids.
  • Three major stages in processing energy-containing nutrients:
    • Stage 1: digestion and absorption in the gastrointestinal tract.
    • Stage 2: in cytoplasm, nutrients are built into macromolecules (anabolism) or partially broken down (catabolism) with glycolysis as the main path.
    • Stage 3: in mitochondria, complete breakdown of stage 2 products (mostly converted to acetyl CoA). This uses oxygen and produces ATP, carbon dioxide, and water.

Cellular Respiration

  • Catabolic reactions involving glycolysis, citric acid cycle, and oxidative phosphorylation.
    • Convert chemical energy of nutrients (e.g., glucose) into usable energy (ATP).

Phosphorylation

  • Transfer of high-energy phosphate groups from ATP to another molecule.
  • Primes molecules for activity, motion, or work.

Oxidation-Reduction Reactions and the Role of Coenzymes

  • Many reactions in cells are oxidation reactions.
    • Oxidation involves either gaining oxygen or losing hydrogen atoms (with their electrons).
    • Oxidized substances lose electrons.
    • O2 is the final electron acceptor; it joins with removed H atoms to form H2O.
  • Dehydrogenases: catalyze removal of hydrogen atoms
  • Oxidases: catalyze the transfer of oxygen
  • NAD+ and FAD: important coenzymes in oxidative pathways.

ATP Synthesis

  • Two mechanisms capture energy to produce ATP:
    • Substrate-level phosphorylation: direct transfer of high-energy phosphate groups from a substrate to ADP, producing ATP.
    • Oxidative phosphorylation: more complex process; mostly produces ATP via an electron transport chain and chemiosmosis.

24.4 Carbohydrate Metabolism

  • Body converts carbohydrates to glucose, which enters cells via glucose transporters.
  • The process is enhanced by insulin.
  • Glucose is phosphorylated within the cell to prevent it from leaving.
  • Only in cells of the intestine, kidney, and liver is glucose released back in.
  • This keeps intracellular concentrations low, which facilitates continued glucose entry via facilitated diffusion.

Oxidation of Glucose

  • Glucose is catabolized through glycolysis, citric acid cycle, and oxidative phosphorylation.
    • Glycolysis: occurs in the cytosol, requires ten chemical steps, produces pyruvate molecules anaerobically, yields 2 ATP molecules, and 2 NADH+H+.
    • Citric acid cycle: occurs in the mitochondrial matrix, generates 2 molecules of CO2, 3 NADH + H+, 1 FADH2, and 1 ATP (as GTP).
    • Oxidative phosphorylation: process mostly occurs in mitochondria through electron transport chain and chemiosmosis. This generates 28 ATP per glucose.

Glycogenesis, Glycogenolysis, and Gluconeogenesis

  • Glycogenesis: The synthesis of glycogen, a large polysaccharide used to store carbohydrate in animals. Most active in liver and skeletal muscle.
  • Glycogenolysis: The breakdown of glycogen to release glucose. Active in liver and some kidney and intestinal cells, releasing glucose into the bloodstream.
  • Gluconeogenesis: The formation of new glucose molecules from noncarbohydrate sources like glycerol and amino acids. It is triggered by low blood glucose, and occurs primarily in the liver and some kidney and intestinal cells.

24.5 Lipid Metabolism

  • Fats are the most concentrated source of energy, yielding twice the energy as carbohydrate or protein.
  • Products of fat digestion are transported in lymph via chylomicrons and enter capillaries for various uses.
  • Glycerol: converted into glyceraldehyde-3-phosphate (a glycolysis intermediate), and eventually to acetyl CoA. Yields about 15 ATP.
  • Fatty acids: undergo beta oxidation in the mitochondria to break down into two-carbon fragments which are reduced, producing FADH2, and NADH+H+, which are used to produce ATP. Each fragment binds with coenzyme A to form acetyl CoA to enter the citric acid cycle.

Lipogenesis and Lipolysis

  • Lipogenesis: Synthesis of triglycerides; stimulated by high glucose levels.
  • Lipolysis: Breakdown of stored fat into glycerol and fatty acids; utilized when carbohydrate intake is insufficient.
  • The breakdown of fatty acids produces acetyl CoA that can be used in the citric acid cycle or in ketogenesis.

24.6 Amino Acids

  • Proteins have a limited life span and must be broken down and replaced.
    • Amino acids are recycled into new proteins or different N-containing compounds (like nucleotides).
    • Cells constantly take up dietary amino acids for tissue protein replacement at rates of ~100g per day.
  • If dietary amino acids are in excess, they are oxidized for energy or converted to fat or glycogen storage.
  • Deamination: removal of the amino group (-NH2). The resulting molecule is converted into pyruvate or a keto acid. Important molecule in these conversions is amino acid glutamate.
  • Three Degradation Events
  • Transamination: transfer of amine groups between molecules.
  • Oxidative deamination: removal of the amine group and its conversion to urea.
  • Keto acid modification: altering of keto acids so they can enter the citric acid cycle.

24.7 Energy Storage

  • Energy is stored in the fed state as glycogen and fat.
  • In the fasting state, energy is released through glycogenolysis and gluconeogenesis from the liver, and lipolysis and ketogenesis from adipose tissues.

24.8 The Liver

  • The liver carries out over 500 metabolic processes. – Carbohydrate metabolism (blood glucose homeostasis). – Fat metabolism (beta oxidation, fatty acid synthesis, lipoproteins, cholesterol). – Protein metabolism (urea synthesis, amino acid metabolism, protein synthesis).

24.9 Neural and Hormonal Control of Food Intake

  • For body weight to remain stable, energy intake must equal energy output.
  • Neural and hormonal factors regulate food intake to maintain energy balance.
  • Short-term regulation: (neural signals from digestive tract, nutrient signals in blood, gut hormones, and other hormones).
  • Long-term regulation: (hormone leptin, and/or other hormones).

Obesity

  • Body mass index (BMI) is a measure used to determine obesity.
    • The clinically defined BMI range for obesity is >30.
  • Obesity is associated with chronic diseases (e.g., inflammation, insulin resistance, type 2 diabetes mellitus, cardiovascular disease, and some types of cancers, etc.).

24.10 Thyroxine and Basal Metabolic Rate

  • Basal metabolic rate (BMR): rate of energy output for essential activities in a fasting, relaxed state at a normal temperature
  • Metabolic rate is affected by several things: – Age and gender – Body temperature – Stress   – Thyroxine hormone levels.

24.11 The Hypothalamus and Thermoregulation

  • The hypothalamus is the primary regulatory center for thermoregulation.
  • Receives afferent sensory input from peripheral and central thermoreceptors and initiates appropriate heat-promoting or heat-loss mechanisms.

Mechanisms of Heat Exchange

  • Body uses four mechanisms of heat transfer:
    • Radiation: loss of heat in the form of infrared waves.
    • Conduction: transfer of heat through direct contact.
    • Convection: transfer of heat via movement of fluids (air).
    • Evaporation: heat loss as water turns to vapor from skin. This is sensible (noticeable) or insensible (unnoticeable) depending on whether the rate of evaporative heat loss matches body's heat production.

Clinical-Homeostatic Imbalances

  • Hyperthermia: occurs when the body's heat loss mechanisms fail. This is a serious medical condition which can lead to heat stroke, which can cause multiple organ failure, including brain damage. Often happens after prolonged or extreme heat exposure.
  • Hypothermia: occurs when body temperature falls below normal and can lead to decreased cellular activities. This condition can lead to a decline in vital signs like blood pressure, respiration rate, and heart rate; and is a medical emergency. Can be caused by prolonged cold exposure.
  • Fever: a regulated increase in body temperature triggered by chemicals called pyrogens as a response to infection that promotes healing, inhibits bacterial growth, and enhances immune response.

Developmental Aspects of Nutrition

  • Good nutrition is essential for all phases of life, particularly during fetal development where sufficient calories, proteins, and vitamins are needed for brain growth.
  • In older adults, medication use can influence nutrient absorption and utilization.

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