jod som gift
Giftigheten hos jod är ett faktiskt problem eftersom det gör det svårt att använda jod för vattenrening där det verkligen skulle behövas -- vid rening av det dagliga dricksvatten för den bofasta befolkningen i stora delar av tredje världen. Då rör det sig om kontinuerligt bruk under människors hela livstid och man måste dessutom ta hänsyn till gravida, spädbarn, folk med sköldkörtelbesvär o.s.v.
Själv tycker jag det verkar okej att använda jod för min egen del -- det viktigaste motargumentet är att det tar så lång tid för att få bort t.ex. giardia -- men alla väljer sin försiktighetsnivå. Som stöd för Edra Egna Upplysta Val har jag därför plockat fram tre summeringar från nätet som verkar hyfsat välgrundade. Kolla i första hand råden från
"The Pharmaceutical Journal" längst ner, de är mest rakt på sak.
Så här tycker "Medicine for Mountaineering", 3rd Ed.:
"Ingested iodine is absorbed as iodide, and an average adult requires 150 to 200 micrograms per day. Daily consumption of one to two liters of water disin>fected with 8 mg/L of iodine would provide 30 to 80 times that amount, but such quantities would not affect most individuals with normal thyroid function. Almost all patients who have developed iodide goiter after consuming excess iodide have consumed far larger amounts for six months to more than 5 years."
(cit från
http://www.pcta.org/plan/water_toxic.shtml )
Följande Abstract från en artikel om jodens farlighet i "Environmental Helth Perspectives Volume 108" från förra året manar till en bedömning från fall till fall:
"Iodine is an effective, simple, and cost-efficient means of water disinfection for people who vacation, travel, or work in areas where municipal water treatment is not reliable. However, there is considerable controversy about the maximum safe iodine dose and duration of use when iodine is ingested in excess of the recommended daily dietary amount. The major health effect of concern with excess iodine ingestion is thyroid disorders, primarily hypothyroidism with or without iodine-induced goiter. A review of the human trials on the safety of iodine ingestion indicates that neither the maximum recommended dietary dose (2 mg/day) nor the maximum recommended duration of use (3 weeks) has a firm basis. Rather than a clear threshold response level or a linear and temporal dose-response relationship between iodine intake and thyroid function, there appears to be marked individual sensitivity, often resulting from unmasking of underlying thyroid disease. The use of iodine for water disinfection requires a risk-benefit decision based on iodine's benefit as a disinfectant and the changes it induces in thyroid physiology. By using appropriate disinfection techniques and monitoring thyroid function, most people can use iodine for water treatment over a prolonged period of time."
(cit från
http://ehpnet1.niehs.nih.gov/docs/2000/108p679-684backer/abstract.html )
Följande summering av faror med jod kommer från
"The Pharmaceutical Journal" Vol 264 No 7080 p134-139
January 22, 2000:
* An excessive iodine intake could lead to effects on the thyroid. Goitre formation has been reported where iodinated water has been used exclusively for some months. The most recent of such reports occurred among peace corps workers whose purifier was yielding water with a concentration of iodine at 10mg/L.18 The goitre does resolve quite rapidly once iodine consumption is reduced. Furthermore, there are no reports of a clinical hyperthyroidism through this practice. It is unlikely that most travellers would use iodinated water exclusively for any length of time, but most products do carry a warning stating that they should not be used continuously for more than a few weeks.
* Because of the theoretical effects on the thyroid, iodination is best avoided in pregnancy and in young children.
* Those people with an allergy to iodine should obviously avoid this method of purification."
(cit från
http://www.pharmj.com/Editorial/20000122/education/travelmedicine3.html )
[Ändrat av rydstedt 2001-05-30 kl 21:41]
