Food Choices: Nutrients and Nourishment BIOL 103 Chapter 1

What is Nutrition? The science of foods (e.g. nutrients and other substances), including the relationships to health and disease; processes within the body (ingestion, digestion, absorption, transport, storage, functions, and disposal of end products); and the social, economic, cultural and their components, and psychological implications of eating.

Factors that Influence Food Choices 1.Sensory 2.Cognitive 3.Genetics 4.Environmental 5.Health status

Why do we eat the way we do? Sensory 1.Flavor/Taste 2.Texture 3.Appearance

Why do we eat the way we do? Cognitive 1.Learned food habits/food reward 2.Social factors 3.Comfort/discomfort foods Behavioral motives 4.Advertising 5.Nutrition and health beliefs

Why do we eat the way we do? Environment 1.Economics 1.Lifestyle 1.Availability 1.Cultural Influences 1.Religion

The American Diet “Meats and potatoes” Americans age 2 and older consume, on average, 2157 calories (based on 2000 calories diet) How healthful is the “American” diet? Too little: fruits, dairy, vegetables, whole grain foods Too much: saturated fat, sodium, and sugar

Nutrients Definition: Any substance that provides nourishment essential for growth and the maintenance of life. Essential vs. Non-essential nutrient – Essential nutrient: ______________________ – Non-essential: _________________________ How to determine if it is an nutrient?

The six classes of nutrients (Problem Set#1, Q2) 1.Carbohydrates 2.Proteins 3.Lipids (fat) 4.Vitamins 5.Minerals 6.Water Macronutrients vs. Micronutrients

General Functions of Nutrients (what do they do in our body) 1.Provide ____________ 2.Regulate ____________ processes 3.Build ______________ body structures

What does Organic mean? Organic or Inorganic? – What does it mean if food is organic, in science?

Carbohydrates Carbohydrates: “hydrate of carbon” – Made of sugar molecules Function: – ________________ for cells and tissues Dietary sources: starches and sugars found in grains, vegetables, legumes (dry beans and peas), fruits, dairy products

Lipids Lipids (fats, oils, cholesterol, phospholipids) – Made of: ______________ ______________________ Functions: 1.Energy storage as triglycerides 2.Carries fat-soluble vitamins 3.Provides structure for body cells Food sources: fats, oils, meat, dairy, some plants (avocado, coconut)

Proteins Made of: ____________ Functions: 1.Energy source 2.Structure for cells/tissues/body structures 3.Regulation of body processes Food sources: meats, dairy products, grains, legumes, vegetables.

Vitamins Made of: carbon, hydrogen, and any one or combo of the following (N, O, P, S, or other elements) Functions: 1.helps regulate body processes 2.help extract energy from carbs, fat, and proteins Food sources: meats, vegetables, grains, dairy, fats

Fat vs. Water-Soluble Vitamins Fat Soluble Vitamins – Stored in larger quantities Water Soluble Vitamins

Minerals Inorganic substances Functions: 1.Structure 2.Regulation Food sources: all food groups

Dietary Minerals – Macrominerals: Na, Cl, K, Ca, P, Mg – Microminerals or “trace minerals”: Fe, Zn, Cu, Mn, Mo, Se, I, Fl

Water Most important nutrient Functions: 1.Temperature control 2.Lubrication of joints 3.Transportation of nutrients and wastes Food sources: beverages, foods like fruits and vegetables.

Macronutrients

Macronutrients: From Food to Fuel

Energy in Food We eat nutrients so that we can gain energy – Energy: capacity to do work – Q: Which nutrients contain sources of potential energy? Kcal vs. Calories How do we measure energy in Nutrition? – Kilocalories (kcal) 1000 calories = 1 kilocalorie 1 kcal: the amount of energy/heat needed to raise the temperature of 1 kilogram (kg) of water by 1 degree Celsius.

Energy in Food Use calorie as a general term for energy and kilocalorie as a specific measurement or unit of that energy.

Problem Set #1, Q3 A) Jeff is eating a snack with 20g of carbohydrates, 5 grams of proteins, and 3 grams of fat. What is the total amount of available energy (in kcal) in his snack? (Note: you will need to show your work for full credit in an exam).

Problem Set #1, Q3 B) Determine the percentages of kilocalories of carbohydrate, protein, and fat in Jeff’s snack.

Many of the leading causes of death can be avoided by good diet and exercise

More than 2/3 of U.S. Adults are overweight/obese

Diet and Health Healthy: “a state of complete physical, mental, and social well-being AND not merely the absence of disease or infirmity.” (WHO) Disease – Acute: ____________________________ Examples: – Chronic: __________________________ Examples:

Diet and Health Factors that influence Obesity: 1.Behavior 1.Calorie imbalance 2.Sedentary lifestyle 2.Environment Barriers to or opportunities for an active lifestyle 3.Genetics Role of heredity

Diet and Health Physical Activity – Role in long-term weight management At least ____ mins/day of moderate activity – Weight-management At least ____ mins/day of moderate activity – What is moderate activity?

Common Study Designs used in Nutrition Research (PS#1, Q 4 and 5) 1.Cell culture studies: effect of nutrients on cells 1.Animal Studies: effect of nutrients on animals 1.Epidemiological studies: study of disease/death rates in population groups 1.Case Control Studies: disease vs. those without disease 1.Clinical/Intervention Trials: experimental vs. control group – Placebo-controlled

Junk Science

Evaluating Information on the Internet There are no rules for posting on the internet Consider the source Keep in mind the scientific method Be on the lookout for “junk science” – May distort facts through omission of details