Human Nutrition and Balanced Diets

Human Nutrition, Digestion, Malnutrition, and Traditional Foods

• Nutrition can be classified as either autotrophic or heterotrophic.
• Autotrophs produce their own food, while heterotrophs obtain food from other sources.
• A balanced diet includes a variety of fruits, vegetables, whole grains, dairy/alternatives, beans, pulses, fish, eggs, meat, and other proteins.
• Unsaturated oils and spreads should be consumed in moderation.
• Drink plenty of fluids (at least 6 to 8 glasses of water daily).
• Foods high in fat, salt, and sugar should be consumed less frequently and in small amounts.
• A portion size is a standard amount of food.
• Fruit and vegetable portions should comprise over a third of daily meals.

Balanced Diets

• Eating a wide variety of foods in the correct proportions is essential for good health.
• People should aim to eat at least 5 portions of fruit and vegetables every day.
• Meals should primarily consist of high-fiber starchy foods.
• Dairy or dairy alternatives (soy alternatives) are important.
• Protein sources like beans, pulses, fish, eggs, and meat are necessary.
• Unsaturated fats should be used in moderation.

Healthy Eating Plate

• The plate model provides a visual guide for a balanced diet.
• The plate emphasizes whole grains, plentiful fruits and vegetables, and lean proteins.
• Healthy oils and plenty of water/non-sugary beverages round out the model.

Food Tests

• Different food tests can identify specific nutrients in different foods
• These tests utilize various chemical processes to discern different foods and ascertain the present nutrients within them.

Functions of the Digestive System

• Ingestion is the process of taking food into the body.
• Digestion is the breakdown of food into smaller molecules.
• Absorption is the uptake of these smaller molecules into the bloodstream.
• Assimilation is the use of absorbed nutrients by the body.
• Elimination/egestion is the removal of undigested material from the body.
• Mechanical digestion involves physically breaking down food (chewing).
• Chemical digestion involves using enzymes to break down food.

Different Diets

• Specific dietary requirements include vegetarian, vegan, pregnancy, and religious-based diets (Halal, Kosher).
• Intolerances like dairy, fish, shellfish, allergies to nuts and gluten in addition to various other food allergies need to be carefully considered when following these diets.

Molecules for Life

• Organic compounds contain carbon and hydrogen (and sometimes oxygen or nitrogen)
• Inorganic compounds are not predominantly made of carbon and hydrogen
• Monomers are small molecules (building blocks), while Polymers are long-chain molecules composed of monomers
• Hydrolysis breaks down polymers with the aid of water.
• Condensation reactions combine monomers to form polymers, and water is produced.

Carbohydrates

• Carbohydrates are composed of carbon, hydrogen and oxygen.
• Monosaccharides (simple sugars) like glucose, fructose, and galactose.

• Disaccharides (formed from two monosaccharides)

• Polysaccharides (complex carbohydrates).
• Polysaccharides like starch, cellulose, and glycogen.

Proteins

• Proteins are composed of carbon, hydrogen, oxygen, and nitrogen.

• Amino acids are the monomers (building blocks) of proteins.

• Proteins have varied structures and roles: enzymes, hormones, etc.

Lipids

• Lipids are composed of carbon, hydrogen, and oxygen.

• Glycerol and fatty acids are the monomers (building blocks).
• Lipids are a key source of energy, and they are insoluble in water but soluble in alcohol, unlike carbohydrates.
• Lipids can be saturated or unsaturated.

Organs of the Digestive System & Functions

• Mouth: Ingestion, mechanical and chemical digestion (saliva).
• Esophagus: Transport of food to the stomach.
• Stomach: Mechanical and chemical digestion (Chyme formation).
• Small Intestine: Digestion and absorption of nutrients.
• Large Intestine: Absorption of water; elimination.
• Liver: Production of bile; detoxification.
• Gall Bladder: Storage and release of bile.
• Pancreas: Production of digestive enzymes; control of blood sugar.
• Rectum: Temporary storage of solid waste.
• Anus: Elimination of solid waste.

Control of Sugar

• Glucose is a simple sugar and glycogen is a complex carbohydrate.
• Insulin and Glucagon are hormones that regulate blood glucose levels.
• The pancreas produces insulin to lower blood glucose and Glucagon to raise it.
• Glycogen is stored in the liver and muscles.

Diabetes (Type 1 and Type 2)

• Type I often occurs in childhood and requires insulin injections
• Type II is less severe, often develops in adulthood, and can be managed with lifestyle changes.

Other Problems Associated with Nutrition

• Inability to cook or eat
• Anorexia
• Food intolerance
• Poor digestion
• Impaired food absorption
• Altered metabolic requirements