Adding iodine to salt played a role in cognitive improvements: research (2013)

Role of Iodine and Public Health Impact

• Commenters highlight iodine deficiency as a major global cause of preventable cognitive impairment, especially in pregnancy, where iodine needs rise significantly.
• Iodine’s role is discussed mechanistically via thyroid hormones (T3/T4) guiding fetal brain development and neuronal migration; deficiencies can disrupt brain-cell placement and long-term cognition.
• The iodization of salt is framed as a textbook public-health success, comparable (in impact style) to sewers, vaccines, and, for some, fluoridated water and shoes.

Sources of Iodine and Changing Salt Use

• Many note that modern diets get iodine from seafood, dairy, and eggs, but levels depend heavily on soil/feed iodine.
• In the US, table salt is often iodized, but kosher, flaky, and “natural sea salt” typically are not. Fast-food chains and home cooks increasingly use non-iodized flake/kosher salt, raising concern about reduced iodine intake.
• Some struggle to find iodized flaky salt; others suggest simple iodine or multivitamin supplements, debating appropriate dosages and heavy-metal concerns in kelp-based products.
• There is mention that iodine content varies by brand, dissipates from open containers, and is partially lost during cooking.

International and Cultural Differences

• Several European countries (e.g., Norway, Germany, Finland) are cited as having inadequate iodine intake due to low iodized-salt coverage and declining milk/seafood consumption.
• Germany is contested: some recall no iodization; others cite data that ~70–80% of household salt sold is iodized (often also fluoridated).
• Japan and Korea are noted for high seaweed consumption; Japan reportedly bans iodized salt as an additive, with some subgroups experiencing excess-iodine thyroid issues. Korea’s seaweed soup is described as a de facto iodine source.

Sodium, Salt Design, and Health

• One line of discussion links high sodium intake to cardiovascular disease, arguing salt is both risk factor and useful iodine carrier.
• Others claim evidence against sodium is weak or confounded by overall diet and suggest that reformulations targeting “saltier-tasting” crystals may just shift hyperpalatability toward sugar and seed oils.
• There is side discussion about physiological mechanisms (osmolality, spikes vs totals) and the difficulty of conveying this nuance to the public.

Fluoridation, IQ, and Tradeoffs

• Fluoridated water is compared with iodized salt as a mass intervention, provoking more disagreement.
• Some cite recent meta-analyses and NTP reviews suggesting higher fluoride exposure (>1.5 mg/L) is associated with small IQ reductions in children, and argue the benefit-to-risk ratio is poor given availability of topical fluoride (toothpaste, mouthwash).
• Others counter that typical US levels (~0.7 mg/L) are below the thresholds where effects have been observed, that evidence at these levels is “insufficient,” and that much fluoride intake comes from food anyway.
• A few invoke fluorine chemistry to argue there is no plausible mechanism for cognitive effects at trace levels; critics respond that lack of a known mechanism should not be over-weighted against suggestive epidemiology.
• Some participants favor fluoridation for population-level dental benefits, especially for poorer communities; others oppose any involuntary exposure, preferring targeted toothpaste programs.

Chemistry and Conceptual Clarifications

• Several comments correct or refine the article’s phrasing that iodine is “something our bodies can’t synthesize”:
  • Iodine, as an element, cannot be synthesized by any organism; it is created in supernovae via nuclear processes.
  • Discussion distinguishes elements vs compounds and notes that many inorganic species (e.g., water, bicarbonate) are biologically synthesized, but not elements themselves.
• There is meta-debate about whether the article’s wording is misleading (by analogy with essential amino acids) or simply context-appropriate shorthand.
• Related tangents cover definitions of “organic” compounds, notation for chemical species (TeX, Unicode, InChI), and the limits of pedantry in popular science writing.

Other Related Public-Health and Environmental Factors

• Hookworm eradication in the American South is cited as another example where a simple intervention (deworming) measurably improved school attendance, cognition, and regional economic outcomes; one commenter notes hookworm’s partial resurgence.
• Bromide exposure is raised as an underappreciated factor: potassium iodate in bread was historically replaced with potassium bromate in the US, which can displace iodide in the thyroid and may increase cancer risk; California has banned bromate.
• Some note anecdotal reports of better tolerance of European bread (possibly linked to absence of bromated flour), while acknowledging potential confounders.