Scientific Method Nutrition Science Textbook Observation Hypothesis Experiment … and that’s it…? Scientific Method

Scientific Method

Scientific Method

Step 1: Observation Accurate – what does it mean? Calorimeter lab – not very specific… Cashews contain a lot of energy, or Beans contain less energy than nuts, or Almonds contains more energy than cashews, or Foods yield more energy when oxidized in a bomb calorimeter, etc. Hypothesis explains the observation Step 1: Observation

Step 2: Hypothesis Plant growth may be affected by the color of light. Ultraviolet light may cause skin cancer. Step 2: Hypothesis

Causative & Correlative If leaf color change is related to temperature, then exposing plants to low temperatures will result in changes in leaf color. If skin cancer is related to ultraviolet light, then people with a high exposure to uv light will have a higher frequency of skin cancer. Step 2: Hypothesis

Complex relationships Correlative Can be a + or - correlation Complex relationships Interactions of many variables Step 2: Hypothesis

Step 3: Experiment Epidemiologic studies Intervention studies

Epidemiology Epi – upon, among Demos – people, district Logos – study, discourse The study of what is upon the people This term is now applied to study of animals and plants as well. Before: epidemic diseases Now: also health-related issues Step 3: Experiment

Epidemiology The science of study of patterns and effects of health conditions in defined populations. Public health studies  policy decision Clinical research  evidence-based medicine Basic research  develop methodology http://en.wikipedia.org/wiki/Epidemiology Step 3: Experiment

Epidemiologists rely on… Scientific disciplines like Biology to better understand disease processes, Statistics to make efficient use of the data and draw appropriate conclusions, Social sciences to better understand proximate and distal causes, and Engineering for exposure measurement. Step 3: Experiment

Many epidemiologists are physicians, or hold graduate degrees such as Master of Public Health (MPH) Master of Science of Epidemiology (MSc.) Doctorates include the Doctor of Public Health (DrPH) Doctor of Pharmacy (PharmD) Doctor of Philosophy (PhD) Doctor of Science (ScD) Doctor of Podiatric Medicine (DPM) Doctor of Veterinary Medicine (DVM) Doctor of Nursing Practice (DNP) Doctor of Physical Therapy (DPT) Doctor of Medicine (MD) Doctor of Osteopathy (DO). Step 3: Experiment

Intervention Studies Control and experiment groups Phenomena that could affect the results Placebo effect Hawthorne effect Researcher bias Preventive measure single- or double-blind study Placebo-controlled Random assignment Step 3: Experiment

The rest of the Scientific Method Step 4: data analysis Step 5: conclusion More: revise hypothesis, reproduce experiment, peer review, more experiments, etc. More: Analysis & Conclusion

Nutrition Claims How do you know which ones are believable? Source of info – primary source ex. peer-reviewed journals Researchers – professors or medical doc Funding Agencies – unbiased, have nothing to gain from the study Scientific method Public health organizations

Source of information Researcher credibility Who paid for the research? Evaluate experimental design Do public health organization agree?

Societal Health "A society is healthy when there is equal opportunity for all and access by all to the goods and services essential to full functioning as a citizen" (Russell 1973). existence of the rule of law the level of social capital equality in the distribution of wealth public accessibility of the decision-making process Gale Encyclopedia of Public Health, 2002

Societal Health How one interacts within social institutions How one gets along with others How people react to this individual Social health has also become relevant with the increasing evidence that those who are well integrated into their communities tend to live longer and recover faster from disease. Conversely, social isolation has been shown to be a risk factor for illness. Gale Encyclopedia of Public Health, 2002

Who Monitors Societal Health World Health Organization (WHO) Centers for Disease Control and Prevention (CDC)

Indicators of Societal Health Mortality rate: no. of deaths in a given population at a given period of time Infant mortality rate: same as above but for babies Morbidity rate = incidence + prevalence no. of sick ppl in a … same as above… Life expectancy: “maximum lifespan” Infectious and noninfectious diseases