4.5 Personal Health, Nutrition & Disease
Key Takeaways
- The six essential nutrient classes are carbohydrates, proteins, fats, vitamins, minerals, and water; fats provide the most concentrated energy at 9 kcal per gram, while carbohydrates are the body's preferred quick-energy source.
- Communicable diseases are caused by pathogens (viruses, bacteria, fungi, and parasites) that spread between hosts, whereas noncommunicable diseases such as asthma, type 2 diabetes, and heart disease cannot be caught from other people.
- The body defends itself through three lines of defense: physical and chemical barriers, the innate inflammatory response, and the adaptive immune response of antibody-producing lymphocytes.
- Vaccines expose the immune system to weakened or inactive antigens so it produces antibodies and memory cells without causing the full disease; antibiotics kill bacteria but have no effect on viruses.
- Handwashing with soap is the single most effective everyday practice for preventing the spread of communicable disease.
Nutrition: The Six Essential Nutrient Classes
Personal health is a required strand of the Praxis 5005 Life Science content area. Elementary teachers must understand basic nutrition, how infectious and chronic diseases differ, and how the immune system protects the body.
Food provides nutrients—substances the body cannot make in sufficient amounts and must obtain from the diet. The six essential nutrient classes are:
| Nutrient Class | Primary Functions | Energy Yield | Key Food Sources |
|---|---|---|---|
| Carbohydrates | The body's preferred quick-energy fuel; fiber aids digestion | 4 kcal/g | Whole grains, fruits, vegetables, beans |
| Proteins | Build and repair muscles, skin, enzymes, and antibodies | 4 kcal/g | Meat, fish, eggs, dairy, beans, nuts |
| Fats (Lipids) | Concentrated energy storage; insulation; build cell membranes; absorb fat-soluble vitamins A, D, E, and K | 9 kcal/g | Oils, nuts, seeds, fish, dairy |
| Vitamins | Regulate chemical reactions and body processes (organic micronutrients) | 0 | Fruits, vegetables, dairy, fortified grains |
| Minerals | Build structures and regulate fluids (inorganic micronutrients) | 0 | Dairy (calcium), red meat and beans (iron), bananas (potassium) |
| Water | Medium for nearly all chemical reactions; transports materials; regulates body temperature | 0 | Drinking water, milk, juicy fruits |
Classic deficiency examples that appear on exams: insufficient iron causes anemia (too little hemoglobin to carry oxygen); insufficient vitamin D and calcium weakens bones (rickets in children); insufficient vitamin C causes scurvy (poor wound healing and bleeding gums).
Balanced Eating: MyPlate
The USDA's MyPlate guide recommends filling half the plate with fruits and vegetables, about a quarter with grains (preferably whole grains), and a quarter with lean protein, plus a serving of dairy. Children should limit added sugars, sodium, and saturated fats.
Communicable vs. Noncommunicable Disease
Disease is any condition that interferes with the normal functioning of the body. The Praxis 5005 expects teachers to distinguish the two major categories:
- Communicable (infectious) diseases are caused by pathogens—disease-causing agents—and can spread from one host to another. The pathogen types are:
- Viruses: non-living particles of genetic material inside a protein coat that hijack living cells to reproduce (common cold, influenza, chickenpox, measles, COVID-19). Viruses cannot be treated with antibiotics.
- Bacteria: single-celled prokaryotes; most are harmless or helpful, but some cause disease (strep throat, tuberculosis, some food poisoning). Bacterial infections can be treated with antibiotics.
- Fungi: cause infections such as athlete's foot and ringworm.
- Parasites: organisms that live on or inside a host, such as head lice or the malaria-causing protist.
- Noncommunicable diseases are NOT caused by pathogens and cannot be caught from other people. They arise from genetics, lifestyle, or environmental factors: asthma, allergies, type 2 diabetes, heart disease, and cancer.
How Communicable Diseases Spread
Pathogens travel through direct contact (touching), indirect contact (shared toys, doorknobs, drinking cups), airborne droplets from coughs and sneezes, contaminated food and water, and vectors—animals that carry pathogens between hosts, such as mosquitoes (malaria, West Nile virus) and ticks (Lyme disease).
The Immune System, Vaccines, and Antibiotics
The body defends itself with three lines of defense:
- First line — barriers: intact skin blocks entry; mucus traps pathogens in the nose and airways; cilia sweep trapped particles upward; stomach acid kills swallowed microbes; tears and saliva contain protective enzymes.
- Second line — innate (general) response: inflammation brings extra blood, heat, and white blood cells to an injury (causing redness and swelling); phagocytes are white blood cells that engulf and digest invaders; fever raises body temperature to slow pathogen growth.
- Third line — adaptive (specific) immune response: white blood cells called lymphocytes target one specific pathogen. B cells produce antibodies—proteins that bind to a pathogen's unique surface molecules (antigens) and mark it for destruction. T cells attack infected body cells. After the infection is cleared, memory cells remain, giving long-term immunity to that pathogen.
Vaccines
A vaccine introduces a weakened, killed, or partial form of a pathogen (its antigens) so the immune system produces antibodies and memory cells without the person suffering the full disease. When a large share of a community is vaccinated, herd immunity slows the spread of disease and protects people who cannot be vaccinated.
Antibiotics and Resistance
Antibiotics (such as penicillin) kill bacteria or stop their reproduction, but they have no effect on viruses. Taking antibiotics for a cold or flu neither helps the patient nor prevents spread—and overuse breeds antibiotic-resistant bacteria through natural selection, a growing public-health threat.
Substance Abuse Prevention (Elementary Level)
Health education also covers how common substances affect the body:
- Tobacco and nicotine are addictive; smoking damages the lungs and heart and is a leading cause of cancer.
- Alcohol slows the nervous system and is especially harmful to the developing brains and livers of children and teens.
- Medicines help when used exactly as directed but can be dangerous when misused; elementary programs teach that only trusted adults should give medicine.
- Classroom prevention focuses on refusal skills, healthy alternatives (exercise, sleep, good nutrition), and talking with trusted adults.
Classroom Application & Common Misconceptions
- Glitter germ handshake: A drop of lotion plus glitter on one student's palm spreads through handshakes and shared pencils, modeling indirect-contact transmission; students then test which handwashing method (quick water rinse vs. soap with 20 seconds of scrubbing) removes the most 'germs.'
- Bread and hands experiment: Students press unwashed, rinsed, and soap-washed hands onto separate slices of bread and observe mold growth over a week.
- MyPlate collage: Students cut out grocery-store pictures and assemble balanced meals, defending their nutrient choices.
Misconceptions to Correct
- Misconception: 'Antibiotics cure colds and the flu.' Correction: Colds and flu are caused by viruses; antibiotics work only against bacteria.
- Misconception: 'All bacteria are germs that make you sick.' Correction: Most bacteria are harmless or beneficial—gut bacteria aid digestion, and others make yogurt, cheese, and compost.
- Misconception: 'Vaccines give you the disease they prevent.' Correction: Vaccines contain weakened, killed, or partial pathogens that cannot cause the full disease; a sore arm or mild fever is the immune system building memory cells.
A student stays home from school with the common cold. Which statement about treating the cold is scientifically accurate?
How does a vaccine protect a child against a communicable disease such as measles?
Which nutrient class provides the most concentrated source of energy per gram (9 kcal/g) and is essential for absorbing the fat-soluble vitamins A, D, E, and K?