Ch 2 - Evaluating Nutrition Info

case study - Pellagra

common disease in early 1900s in prisons, orphanages, mental institutions

• Joseph Goldberger discovered cause was dietary deficiency among poor, prisoners, orphans, etc

  • 1. fed better foods to patients and were cured

  • 2. clinical study

  • 3. 1916 → “filth party” (fed secretions of pellagra patients to ppl; did not get sick)

• not believed until 1937 (Dr. Elvehjem’s team isolated niacin (vit B3) from liver extracts; showed it cured pellagra-like disease in dogs)

  • Nixtamalization = process for prep of corn or other grain; grain soaked in alkaline (limewater) solution

    • benefit → nutritional value increased (helps tryptophan in corn be absorbed by humans) = prevent niacin deficiency (pellagra)

past nutrition facts/practices

based on

• intuition

• common sense

• conventional wisdom

• anecdote

scientific method

1. make observations that generate questions

2. formulate hypotheses to explain events

3. review current scientific literature (published studies) that relate to the questions

4. design studies, perform tests, and collect data (facts)

5. analyze data and draw conclusions based on the results

6. share results w/ peers (report findings)

7. conduct more research, the results of which may confirm or refute previous findings

experiment

a systematic way to test a hypothesis

• often tested on cells (“in vitro”) or in small amounts (“in vivo”)

• small rodents often used

• animal research first, human research last → safety and ethical concerns

• humans don’t make best subjects

  • population variability and cooperation

experimentation

most have two groups

• treatment group → receives treatment

• control group → doesn’t receive treatment; human subjects may receive placebo

  • placebo → fake treatment (sham pill, injection, medical procedure)

experimental (intervention)

gains info a/b health conditions that may have resulted from specific dietary practices

• experimental vs control groups

• challenges

  • ethics

  • large groups

  • human variation

  • participation commitment

observational (epidemiological)

most epidemiological research observational (human experimentation has severe ethical challenges)

• examples

  • case-control study

  • cohort study

• limits → correlation vs causation

case-control study

comparison between individuals w/ a health condition to individuals w/ similar characteristics w/o the condition

• example of epidemiological research

cohort study

study that measures variable in a group of ppl over time

• example of epidemiological research

reasons for conflicting scientific results

1. parameters were different

2. science is constantly evolving

3. research bias

4. media communication

evidence-based

anecdotes

personal accounts or individual experiences used to illustrate, contextualize, or generate hypotheses

• red flag in nutrition info online

control groups

don’t receive treatment; human subjects may receive placebo

epidemiology

study of the occurrence, distribution, and causes of health problems in populations

correlation

statistical measure that describes size and direction of relationship between two or more variables

• cannot determine causation

positive correlation

statistical relationship between two variables that move in same direction

• as one variable increases/decreases, other variable also increases/decreases

negative correlation

statistical relationship where two variables move in opposite directions

• as one variable increases, other variable decreases

pseudoscience

sounds scientific, but is BS

• ex: “enzymatic therapy”, “colloidal extract; metabolism killer”

quackery

promotion of useless medical treatments

SIFT

tool for using internet wisely

• S - stop

• I - investigate the source

• F - find better coverage

• T - trace claims, quotes, and media to original context

conventional medicine

follows evidence-based results; info that is based on results of scientific studies; FDA and medical establishments follow this

complementary and alternative medicine (CAM)

• use of supplements to treat disease or promote good health

• chiropractic manipulations

• acupuncture

• homeopathy and naturopathy

• massage therapy

integrative medicine

practice of using CAM along w/ conventional medicine

drug

a substance, natural or man-made, that alters body functions

• FDA responsible for ensuring safety and efficacy of medications and other health-related products

dietary supplements

regulated as “food”, not drugs

• includes

  • nutrient pills (ex: multivitamin/mineral products)

  • protein powders

  • herbal extracts (ex: teas)

  • energy bars (ex: protein)

• bypasses strict FDA regulations imposed on drugs

regulation of dietary supplements

bypasses strict FDA regulations imposed on drugs (don’t have to submit evidence to support health claims)

• regulation to some extent

  • safety, labels, and claims allowed

  • only gets involved in regulation of supplements after they reach marketplace

  • recalls only after reports of serious adverse health affects

reasons for taking supplements

• boost nutrient intakes

• prevent some diseases

• obtain more energy

• treat existing ailments

• doctor prescribes (e.g., prenatal vitamins)

common non-nutrient supplements

• coenzyme Q-10

  • claims → increase exercise tolerance, prevents heart disease and cancer, reverses signs of aging

  • major research needed to determine benefits

  • not FDA approved

• green tea

  • claims → prevents/treats cancer, promotes weight loss, reduces blood cholesterol levels

  • useful for genital warts, lack of evidence for others

  • associated w/ liver problems in some cases and caffeine content effects