Nutrition: an interdisciplinary science that studies factors that affect:

• food availability + choices

• the chemical + physiological processes

• involved in processing + delivering chemical components of foods to cells throughout our body

• how those chemicals affect our health every day

The substances we consume are broken down to fuel activity and to build + support the body's tissues.

Nutrition scientists study food + its components.

Nutrient: a component in food | a chemical substance required for growth + maintaining proper body functioning

• the body can produce many of its own nutrients

• vitamins and minerals must be supplied through what we eat + drink

• what you eat, the specific quantity, + the variety of nutrients in foods can promote health/increase your risk of disease.

• regulates numerous body processes

• supplies building blocks of key body structures (cell membranes, muscles, + bones)

• required for normal growth, development, reproduction, maintenance, + repair of cells

• critical role in maintaining homeostasis

  • the process by which the body maintains a stable internal environment in the face of external variability

  • regulates the balance of fluids, pH, + body temperature.

Macronutrients: needed in large quantities to stay healthy

• Carbohydrates

  • supply energy +/ a large portion of the structural components in our body

• Proteins

  • supply energy +/ a large portion of the structural components in our body

• Lipids

  • supply energy +/ a large portion of the structural components in our body

• Water

Micronutrients: needed in smaller amounts

• Vitamins

  • do not supply energy/calories

  • crucial to normal growth + development

• Minerals

  • do not supply energy/calories

  • crucial to normal growth + development

Phytochemicals (aka phytonutrients): chemicals in plants beneficial to human health

• found in vegetables, fruits, + whole grains

• give plants key properties such as color, aroma, + flavor

  • lycopene: gives tomatoes + watermelon their red color + reduce risk of cancer

• can promote health due to hormone-like actions/repair + prevent damage to cells

  • anthocyanins: give berries their blue/purple color + act as antioxidants.

Malnutrition: a state of inadequate/unbalanced nutrition

• undernutrition: lack of food/specific essential nutrients (nutrient deficiency)

• overnutrition: excess of essential nutrients

  • obesity: a condition characterized by excess body fat

    • overconsumption of too many calories along with too much solid fat, sugar, and sodium.

    • often associated with other health problems

      • slow progression (heart disease + type 2 diabetes)

    • relatively new public health concern. Historically, nutrition policy and research focused on making

Dietary Reference Intake (DRI) values: quantitative estimates of nutrient intakes to be used to plan + assess diets

• avoid nutrient deficiency + help optimize health, prevent disease, + avoid overconsuming nutrients

• Estimated Average Requirements (EARs): the average amount of a nutrient needed by people grouped by sex + age

  • meets the nutritional requirements of 50% of individuals within a group (not recommendations for individuals)

    • half of the population would be eating less than they need at this level of intake

  • used to assess nutrient adequacy of populations

• Recommended Dietary Allowances (RDAs): average daily amount of a particular nutrient that meets/exceeds the requirements of healthy individuals

  • decrease risks of chronic disease

  • it is not needed to meet the RDA daily

  • adequate, balanced, + varied diets allow the average daily intake to meet the dietary allowances over the course of several days

    • inadequate intake: bodies tap into nutrient storages to meet immediate needs

      • increasing nutrient absorption and/or decreasing excretion to maintain adequate supplies

• Adequate Intake (AI) value: used when there is insufficient evidence

  to generate EARs for a nutrient

  • based on best available data

• Chronic Disease Risk Reduction Intake (CDRR): characterizes nutrient intakes expected to reduce risk of developing chronic disease

• Tolerable Upper Intake Levels (ULs): safe limits of nutrients with the highest average daily amount of a nutrient consumed without risk of toxicity.

• Estimated Energy Requirement (EER): average amount of calories needed in order to maintain weight.

  • meets energy requirements of 50% of the population

  • exceeds the needs of nearly 50% of individuals

• Acceptable Macronutrient Distribution Ranges (AMDRs): healthy range of intakes for carbohydrates, protein, + total fat

  • expressed as a percentage of total calories

    • carbohydrate intake: 45% - 65%

    • protein intake: 10% - 35%

    • fat intake: 20% - 35%

The Scientific Method:

1. start with an observation + identifying a question/problem to investigate further.

2. come up with a testable hypothesis (a proposed explanation for an observation that can be tested through experimentation)

3. complete the experiment

4. publish findings in a scientific journal.

Elements of the scientific process:

• control group: contains no active properties

  • studies that look at the effect of medications, the control group receives a placebo

    • placebo effect (psychological phenomenon in which people feel better after receiving a treatment simply because of expectation that they will)

    • eliminating the placebo effect: people do not know what they are receiving

• Randomized Controlled Trials (RCTs): rigorously compare experimental interventions with controls

  • randomly assigns people to each category to offset potential bias

• Epidemiological + Animal Studies: explore + evaluate the role of diet + dietary components in health + disease