Eat less salt and die' indicates various scientific tenets. The author argues that hitherto injunctions on unhealthiness of salt and prescriptions to reduce dietary intake of salt are misguided. On the contrary, salt far from being unhealthy, is healthy and should not be controlled in the least. In order to most effectively evaluate Teitelbaum's argument, we need to assess various characteristics that primarily include the reliability and validity of the sources that he used per conclusion.
The study that Teitelbaum primarily leans on was one reported by the Journal of the American Medical Association and published May 4, 2011. Conducted by researchers at the University of Leuven in Belgium, Stolarz-Skrzypek et al. measured an impressively large sample of healthy individuals (n= 3.681) with range 20 to 60 and beyond. Urinary sodium levels indicate intake of salt. Tracking the health of these individuals for the next 8 years, the researchers discovered that those with the highest urinary sodium levels had, contrary to popular belief, the lowest risk of developing hear disease, compared to the high-salt people. The conclusions of the study, as Teitelbaum pointed out, contradict the prescriptions of the American Heart Association (AHA), which suggests that people should limit their salt intake to 1500 mg per day. Salt intake may be deleterious to people who suffer from congestive heart failure or high blood pressure, but cutting back may actually be detrimental for the body "the salt-needing body naturally triggers you to eat more salt when you try to cut back" (Teitelbaum, Psychology Today).
There are various characteristics that make this quantitative study reliable. Firstly an impressive sample of people was used. The larger the sample the more plausible the alleged significance (Breakwell et al.) specially if random selection (as in this case) was used. Secondly, the study was well-matched in age and sex and, thirdly, the study was a longitudinal one ascertaining that researchers allowed a feasible amount of time to elapse before concluding that massive consumption of salt did not result in serious illness. The researchers also made sure to select an equal number of participants from each of 6 subgroups by sex and age (20 to 60+). Also positive was the fact that the same participants were used throughout; that participants were repeatedly monitored; and that in all study phases, the same standardized measures were applied. These included tools to measure clinical and biochemical variables, questionnaires, and general monitoring to determine fatal and non-fatal outcomes. A 24-hour urine sample was collected from participants at baseline and, in 2008; another urine sample was collected from participants in two different locations. Blood pressure was also measured at baseline and follow-up with mercury sphygmomanometers. Surveys questioned medical history; smoking status; drinking habits; medication use including contraceptives and hormone replacement therapy; and educational levels. Venous blood samples collected blood glucose and serum total cholesterol measurement. Diabetes was also tested for by self-reported diagnosis, fasting glucose level, or use of antidiabatic agents.
The "International Classification of Disease" manual was used to code immediate and underlying causes of death for any of the participants, and information was also collected on 2856 participants on the incidence of nonfatal events via that same standardized questionnaire that was used at baseline. For the hypersensitive cohort, Chi-square and normal z test were used for descriptive statistics, whilst non-parametric statistics (e.g. Shapiro-Wilk) were used to assess inferential results. A multiple Cox regression analysis was used to assess correlation with the dependent variables being sex, age, blood pressure level, body mass index, alcohol intake, use of hypertensive drugs, urinary potassium excretion, educational attainment, smoking status, total cholesterol level, and diabetes. The study conformed to strict ethical requirements.
For the blood pressure cohort, researchers used the t test and the McNamara test with statistical methods including single and multiple linear regressions. Associations between blood pressure and explanatory variables were investigated, whilst accounting for family clusters and adjusting for co variables. In short, the many and intricate considerations and precautions that were involved with and included into consideration of the study, as well as its cross-sectional breadth and longitudinal monitoring, indicate internal and external validity and reliability of this study.
The shortfalls with this study are, however, several. Firstly, correlation is not cause. For all we know, some other factor may have been inherent in these people (perhaps their genes, specific age factor, or healthy characters for instance) that disabled intake of slat…