So What is Nutrition 1 The science of

So What is Nutrition? 1. The science of foods and their components (nutrients and other subjects), including the relation ship to health and disease; processes within the body (ingestion, disgestion, absorption, transport, disposal) and the social, economic, cultural and psychological implications of eating.

Definitions you need to know! • • • Essential vs. nonessential nutrients Organic vs inorganic foods Organic vs inorganic nutrients Macro vs micro nutrients Phytochemicals Antioxidants

Nutrients and Nourishment • The science of nutrition • Identifies amount of food we need • Recommends best food sources • Identifies components in food that are helpful or harmful – Helps us make better choices • Improves our health • Reduces our risk of disease • Increases our longevity

Nutrients and Nourishment • Why do we eat the way we do? – Food preferences • Enjoyment • Nourishment • Age © Andy Lim/Shutter. Stock, Inc.

Influences on Food Choices • Sensory influences and personal preferences – Taste, texture, and smell • Flavor • Classic tastes: sweet, sour, bitter, salty, and umami – Habits – Comfort/discomfort foods • Behavioral motives

Influences on Food Choices • Sensory influences – Advertising and promotion – Food and diet trends – Social factors – Nutrition and health beliefs Courtesy of the Milk Processor Education Program.

Influences on Food Choices • Environment – Where you live – How you live – Who you live with – Obesogenic environment • Living in an environment that promotes the overconsumption of calories and discourages physical activity and calorie expenditure

Influences of Food Choices • Environment – Economics • Where you live and the surrounding climate – Lifestyle • Foods prepared away from home – Availability • Poor access to nutritious foods

Influences of Food Choices – Cultural influences • Tradition or cultural background – Religion • Religious rites, symbols, and customs – Social-ecological model • Dietary Guidelines for Americans • Individual factors, environmental settings, various sectors of influence, and social and cultural elements of society

The American Diet Reproduced from US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans, 2010. 7 th ed. Washington, DC: US Government Printing Office; December 2010.

The American Diet Reproduced from US Department of Agriculture and US Department of Health and Human Services. Dietary Guidelines for Americans, 2010. 7 th ed. Washington, DC: US Government Printing Office; December 2010.

How healthful is the “American” diet? -Too little nutrient-dense foods • Nutrient density is a ratio of nutrient content (in grams) to the energy content (in Kcalories). Nutrient-dense food is opposite to energydense food (also called “empty calorie" food). Nutrient-dense foods provide substantial amounts of vitamins and minerals and relatively few calories. Fruits and vegetables are the nutrient-dense, while products containing added sugars, processed cereals, and alcohol are not. – Too much of the foods known to be harmful • Sodium, solid fat, saturated fat, and sugar Photo © Photo. Disc

Introducing the Nutrients • Nutrients – Functions • Normal growth and development • Maintaining cells and tissues • Fuel to do physical and metabolic work • Regulating body processes

Introducing the Nutrients • Nutrients – Essential nutrients • Body cannot make them, or cannot make enough – Six classes of nutrients • • • Carbohydrates Lipids (fats and oils) Proteins Vitamins Minerals Water

Introducing the Nutrients • Definition of nutrients – Absence from the diet results in a specific change in health – Putting the chemical back in the diet will reverse the change in health – Not only chemicals in food • Phytochemicals • Antioxidants

Introducing the Nutrients • Classifications of nutrients – Macronutrients • Carbohydrates, lipids, and proteins – Micronutrients • Vitamins and minerals – Organic (contain carbon) • Carbohydrates, lipids, proteins, and vitamins – Inorganic • Minerals and water

Introducing the Nutrients • Nutrients and energy – Energy • The capacity to do work – Energy sources • Carbohydrates, lipids, protein – Measure of energy • Kilocalorie – 1, 000 calories = 1 kilocalorie

Introducing the Nutrients • Energy in foods – Measured in kilocalories (kcal)

Introducing the Nutrients • Energy in foods – When is a kilocalorie a calorie? • Calorie • Kilocalorie – Specific measurement or unit of energy in food – General term for energy in food

Introducing the Nutrients • How can we calculate the energy available from foods? – Example 30 g carb × 4 kcal/g = 156 kcalories 10 g protein × 4 kcal/g = 40 kcalories 16 g fat × 9 kcal/g = 144 kcalories TOTAL = 340 kcalories

Introducing the Nutrients • Be food smart – Calculating the percent of calories in food To limit fat intake to 20– 35% of total energy intake: 2, 000 kcal food × 0. 35 = 700 kcal from fat/9 kcal/g = 77. 8 g of fat allowed per day

Diet and Health • Disease – Acute • Short-lived illnesses – Chronic • Diseases with a slow onset and long duration

Diet and Health

Diet and Health • Obesity: public health crisis – More than two-thirds of U. S. adults are overweight or obese – Increases health risks • Coronary heart disease • Cancer • Diabetes • Hypertension • Metabolic syndrome

Diet and Health • Obesity – Factors that influence obesity • Behavior – Calorie imbalance • Environment – Barriers to or opportunities for an active lifestyle • Genetics – Role of heredity

Applying the Scientific Process to Nutrition • Scientific process – Test hypothesis • Common study designs – Epidemiological studies – Animal studies – Cell culture studies – Case control studies – Clinical trials • Randomized • Double-blind • Placebo-controlled

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”