Forskning i jod av dr. Sebastiano Venturi

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(Introduksjon til denne tråden er skrevet av Anisa.)

"Kjertelen monterer 4 stk. Jodatomer på Thyrosinet og så har vi et T4 molekyl. Dette T4 bruker ikke kroppen til noe, men det er utgangspunktet til T3. Alle friske som har et fungerende kjertelsystem MÅ ha Jod til denne prosessen. Dette er imidlertid det eneste i kroppen som bruker jod.

Det vil si at hvis du IKKE har et fungerende kjertelsystem og spiser ferdig konstruerte T4 thyroxiner, så den Jod som evetuellt finnes i ditt legeme vil ikke bli brukt til noe som helst og bare hoper seg opp til inga nytte og skaper problemer istedenfor."

Lad os høre, hvad "videnskaben" siger til påstanden om at jod er kun for de friske, med sunde og velfungerende skjoldbruskkirtler, mens alle vi andre skal undgå jod, så det ikke "hoper seg opp til inga nytte og skaper problemer istedenfor".

Mere "videnskabeligt" end tidsskriftet Current Chemical Biology kan det næsten ikke blive, og netop i indledningen til Volume 5, Number 3, September 211 læser vi bl.a. følgende (her maskinoversat til norsk):

"De fleste studier av jod-metabolisme hos mennesker og dyr har fokusert på dets rolle i skjoldbruskkjertelens funksjon. Offentlig folkehelsepolitikk ble etablert for å forsyne jod-mangelfulle populasjoner med den nødvendige mengden av dette elementet for å utrydde jodmangelsykdommer, primært kretinismen. Imidlertid indikerer betydelige beviser på at jod kan også være innblandet i fysiologien av andre organer.

Hos mennesker er den totale mengden av jod i kroppen mellom 30 til 50 mg, og mindre enn 30% av det er til stede i skjoldbruskkjertelen og dens hormoner. Omtrent 60% av total jod er ikke-hormonelt og konsentreres i de øvrige vev og organer"...

... til hvad nytte mon, snupper resten af kroppen hele 60% af det daglige jod, mens skjoldbruskkirtlen og thyreoidea-hormoner i kirtlen og i blodbanen nøjes med kun 40%? Så er det godt, at vi har en jod-klog italiener til at besvare det spørgsmål.


Forskning i jod av dr. Sebastiano Venturi

Source: https://sites.google.com/site/iodinestudies/

Ikke mange ved, at den italienske læge Sebastiano Venturi er en af verdens førende forskere i jod, blandt medicinsk-videnskabelige jod-kapaciteter som dr. Guy E. Abraham, farmaceuten phD dr. Jorge Flechas, dr. David Brownstein m.fl. Dr. Venturi har været den første videnskabsmand, der observeret ligheder mellem krybdyrenes stofskifte og sygdommen hypothyreose (lavt stofskifte), relateret til, og ubrydeligt forbundet med jod.

For alle der er blevet følelsesmæssigt, mentalt og intellektuelt udmarvet af den "moderne" reality-kultur, overfyldt til randen med tanketomme ansigter fulde af "mascara, blekede tenner, sillikon i pupper eller lepper, hold-in og push-up", tillige rigeligt krydret med tidens hipsters skønheds-karikaturer.... kan interessen for dr. Venturis jod-forskning - for det rette sind og intellekt - blive en ganske overraskende interessant, og opbyggende oplevelse...

Dr. Sebastiano Venturi er født d. 2. maj 1947 i Italien, i byen Pennabilli beliggende tæt på den gamle republik San Marino, i provinsen Pesaro e Urbino. Efter almindelig skolegang i fødebyen Pennabilli flyttede han til Bologna. I 1972 dimitterede han med udmærkelse i medicin og kirurgi fra Bologna Universitet. Fra 1972 til 1987 arbejdede dr. Venturi som læge ved flere hospitaler i Italien, herunder i National Health Service i Institut for Hygiejne & Sygdomsforebyggelse, og i Afrika.

Fra 1989 til 2002 arbejdede dr. Venturi indenfor medicinsk forskning ved Endokrinologisk Fakultet på Pisa University hos prof. Aldo Pinchera. I årene 2004-2007 var dr. Venturi lektor ved "Thyroid Club" årsmøder på Bologna og Urbino og Perugia Universiteter. Dr. Venturi er forfatter til over 70 internationale og nationale videnskabelige publikationer, to monografier (1978 og 2012), fem bog-kapitler (1987, 1990, 2006, 2010, 2011), og to bøger (1978, 1985). Dr. Venturis Curriculum Vitae kan læses her.

Dr. Venturis ekspertområder:

• Jod som antioxidant;
• Struma;
• Neuropsykologiske patologier;
• Kretinisme;
• Jodmetabolisme;
• Immunitet;
• Forebyggelse af jodmangel;
• Autoimmun Atrofisk Gasrtritis;
• Mavekræft;
• Brystkræft;
• Spytkirtler;
• Oral sundhed;
• Biokemisk evolution af liv på Jorden.

Indenfor disse emner, inviteres dr. Venturi til at reviewe artikler publiceret i følgende tidsskrifter:

• Clinical Chemistry and Laboratory Medicin,
• International Journal of Cancer,
• Acta oncologica,
• Tumor Biology, Thyroid,
• Surgery Today,
• European Journal of Nutrition,
• Endocrine-Related Cancer,
• Nature,
• Aquacultur,
• Journal of Pediatric Biochemistry,
• Clinical Nutrition.

Ressources:

• Dr. Sebastiano Venturi. Iodinestudies
• Sebastiano Venturi - Academia.edu
• Sebastiano Venturi - Publications - ResearchGate
• Sebastiano Venturi - Google Scholar Citations
• Sebastiano Venturi - YouTube
• Sebastiano Venturi - Slideshare.net

Dr. Venturi er sandsynligvis den nulevende forsker der ved mest om betydningen af mineralet Jod, og hans ekspertområde spænder vidt fra viden om den rolle jod har spillet indenfor opståen af liv på vores planet, og til den rolle som jod og jodmangel har spillet, og fortsat spiller både medicinsk, socialt og økonomisk på planeten Jorden, i generationerne siden 1950-erne. Dr. Venturi er medlem af The Italian Thyroid Association (AIT).

Dr. Venturis hjemmeside er enkel, nogen vil endda driste sig til at kalde den "primitiv" eller "lavteknologisk". Den er i hvert fald ikke "moderne". Hvis man ønsker at nyde det sidste nye indenfor det ypperligste webdesign, skal man styre udenom dr. Venturis hjemmeside. Ønsker man derimod at få indblik i jod, jod-historie og jod-kundskab på højeste niveau - kommer man ikke til at surfe forgæves på dr. Venturis hjemmeside.

Herunder følger en "klikbar" liste med links til dr. Venturis vigtigste artikler. Foreløbig tæller listen 28 henvisninger. Den bliver opdateret efterhånden som der evt. dukker flere op, skrevet på, eller oversat til engelsk. Enjoy.

1. Indledning
2. Iodine and Evolution (Iodo ed Evoluzione)
3. Evolutionary significance of iodine.
4. Environmental iodine deficiency: a challenge to the evolution of terrestial life?
5. Evolution of dietary antioxidants: role of iodine.
6. Evolution of dietary antioxidant defences.
7. Iodine, thymus and immunity.
8. Role of iodine in delayed immune response.
9. Iodine in evolution of salivary glands and in oral health. (1)
   Iodine in evolution of salivary glands and in oral health. (2)
10. Thyroid hormone, iodine and human brain evolution.
11. Iodide, antioxidant function and omega-6 and omega-3 fatty acids: a new hypothesis of a biochemical cooperation?
12. Selenium and iodide: ancient antioxidants of cellular membrane lipids?
13. Iodine, PUFAs and iodolipids in health and diseases: an evolutionary perspective. (1)
    Iodine, PUFAs and iodolipids in health and diseases: an evolutionary perspective. (2)
14. Is there a role for iodine in breast diseases?
15. Does iodide in the gastric mucosa have an ancient antioxidant role? 1998
16. Role of iodine in evolution and carcinogenesis of thyroid, breast and stomach.
17. Dietary Iodine and Gastric Cancer
18. Iodide, thyroid and stomach carcinogenesis: evolutionary story of a primitive antioxidant?
19. Syndrome thyro-gastric. Study on the relation between alimentary iodine deficiency and gastric cancer
20. A new hypothesis: iodine and gastric cancer
21. Iodine, Helicobacter Pylori, Stomach Cancer & Evolution.
22. Iodine, Evolution and Gastric Carcinogenesis.
23. Clinical picture of endemic cretinism in central Apennines .
    Iodine Deficiency in the Population of Montefeltro, A Territory in Central Italy Inside the Regions of Emilia-Romagna, Tuscany and Marche.
24. Audiological and neuropsychological development study in a sample of school children from a low-iodine area of the Central Apennines that is endemic for cretinism.
    An iodine-deficient area with endemic cretinism in the Central Apennines: studies of neuropsychological development in schoolchildren.
25. Humoral thyroid autoimmunity is not involved in the pathogenesis of myxedematous endemic cretinism.
26. Extrathyroid Iodine Deficiency Disorders. What is the real iodine requirement?
27. Enigma of the function of iodide in primitive algae and in animal extrathyroidal organs: is it an ancient antioxidant?
    The enigma of the function of thyroxine in animal extrathyroidal organs and in primitive stomach.
28. Preliminary study on the relation between alimentary iodine deficiency and gastric cancer: specific prevention prospects (1985 Book in Italian)

Dagens slogan: "Jod er ikke helse, men helse uden jod varer ikke længe!"

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Iodine and Evolution.

Iodine and Evolution
Venturi S
Published in Italian online: February 8, 2004

SUMMARY
The authors report their hypothesis on the antioxidant role of iodine in the evolution of life on the earth. Iodine is the most electron rich of the essential elements in the animal diet, and as iodide (I-) enters in the cells by an iodide transporter. Iodide, which acts as primitive electron donor by peroxidase enzymes, seems to have an ancestral antioxidant function in all iodide-concentrating cells from primitive marine algae to more recent terrestrial vertebrates.

Thyroxine and iodothyronines seem also to have an antioxidant activity, by deiodinase enzymes, which are donors of iodides and indirectly of electrons. Thyroid cells phylogenetically derived from primitive gastroenteric cells, which during evolution, migrated and specialized in uptake and storage iodine-compounds in the new follicle, as reservoir of iodine, for a better adaptation of modern vertebrates to iodine deficient terrestrial environment.

INTRODUCTION
Iodine (I) is the most electron rich of the essential elements in the animal diet, and as iodide (I-) enters in the cells. Inorganic iodide is necessary for all living cells, but only the vertebrates have a thyroid gland and its iodinated hormones. In humans, the total amount of iodine is about 25-50 mg and about 60-70 % of total iodine is non-hormonal which is concentrated in non-follicular extrathyroidal tissues, where its biological role is still unknown. Sodium iodide symporter (NIS) of iodide pump, which was in 1996 genetically characterised and cloned (1, 2), is a transmembrane protein which actively transports iodide into the cells.

Extrathyroidal NIS, more primitive than the thyroidal one, have a lower affinity for iodide and does not respond to more evolute TSH (Thyrotropin). We believe that the mechanism of iodide-pump (and NIS) is very ancient in the cells, and for this reason, there is a rather surprising lack of specificity for the anions. The pump is not able to distinguish iodide from other anions of similar atomic or molecular size, which may act as pseudo-iodides: thiocyanate, cyanate, nitrate, pertechnetate, perchlorate, etc. On the contrary, this pump is partially able to defend itself and the cell from toxic I-excess (Wolff-Chaikoff effect) (3, 4).

IODINE AND EVOLUTION
Over three billion years ago, blue-green algae (Cyanobacteria), which are the most primitive oxygenic photosynthetic organisms, ancestors of multicellular eukaryotic algae that contain the highest amount of iodine (1-4 % of dry weight) and peroxidase enzymes, were the first living cells to produce poisonous oxygen in the atmosphere (5, 6, 7). Therefore algal cells required a protective antioxidant action in which iodides with peroxidase seem to have had this specific role (8, 9, 10).

In fact iodides are greatly present and available in sea-waters, where algal phytoplankton, the basis of marine food-chain, acts as a biological accumulator of iodides, selenium (and n-3 fatty acids). The sea is rich in iodine, about 60 micrograms (ug) per litre, since this is where most of the iodine removed and washed away from the soil accumulated by the glaciations ages.


Read more / les mer... (Sites.google.com The link is to the English summary, as well as the Italian article complete with pictures and diagrams.)

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Evolutionary significance of iodine.

Evolutionary significance of iodine.
Chapter of book published in Current Chemical Biology: Volume 5, 3 Issues, 2011

Abstract: The significance of inorganic and organic forms of iodine in the evolution of plants and animals is reviewed. Iodine is one of the most electron-rich atoms in the diet of marine and terrestrial organisms, and it enters cells via iodide transporters. Iodide, which acts as a primitive electron donor through peroxidase enzymes, has an ancestral antioxidant function in all iodide-concentrating cells from primitive marine algae to more recent terrestrial vertebrates. Similarly, thyroxine and iodothyronines show antioxidant activities through deiodinase enzymes.

About 500-600 million years ago, in parallel with the evolution of the primitive brain in marine animals, thyroid cells originated from the primitive gut in vertebrates, migrated, and specialized in the uptake and storage of iodo-compounds in a novel follicular “thyroidal” structure, an adaptation that enabled the transition from the iodine-rich ocean to the iodine-deficient terrestrial environment.

Keywords: Antioxidants, evolution, iodine, iodide, thyroxine.


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Environmental iodine deficiency: a challenge to the evolution of terrestial life?

Environmental iodine deficiency: a challenge to the evolution of terrestial life?
Sebastiano Venturi, Francesco M. Donati, Alessandro Venturi and Mattia Venturi
Published in "Thyroid", 2000 Aug;10 (8):727-9.

Iodine is the heaviest and richest in electrons among essential elements required in the diet. Inorganic iodides are necessary for all living vegetal and animal cells, but only the Vertebrates have the thyroid gland and its iodinated hormones. In humans the total amount of iodine is about 30-50 mg and less than 30 % is present in thyroid gland and in its hormones. About 60-80 % of total iodine is non-hormonal and it is concentrated in extrathyroidal tissues, but its biological role is still unknown. Recently we have hypothesized that iodide might have an ancestral antioxidant function in all iodide-concentrating cells from primitive Algae to more recent Vertebrates (1-7). Into these cells iodide acts as an electron donor in the presence of H2O2 and peroxidase (8), the remaining iodine readily iodinates the tyrosine and (more slowly) the histidine or some specific lipid (9), and so, neutralizes its own high oxidant power.

IODINE, THYROXINE AND THYROID EVOLUTION

Over three billion years ago, blue-green algae (Cyanobacteria), which are the most primitive oxygenic photosynthetic organisms, ancestors of multicellular eukaryotic algae, that contain the highest amount of iodine, were the first living cells to produce oxygen, which was toxic at that time, in the terrestrial atmosphere. So, algal cells required a protective antioxidant action in which iodides might have had this specific role. In fact iodides are greatly present and available in sea-waters, where algal phytoplankton acts as a biological accumulator of iodides. Recently our hypothesis of the ancestral antioxidant action of iodides has experimentally been confirmed in some algae by an important study carried out by Kupper et al.(10). Since about 700 million years ago thyroxine (T4) is present in fibrous exoskeletal scleroproteins of the lowest invertebrates (Porifera and Anthozoa)(11), without showing any hormonal action. When some primitive marine vertebrates started to emerge from the iodine-rich sea and transferred to iodine-deficient fresh water and finally land, their diet became iodine deficient and also harboured vegetal iodide-competitors such as nitrates, nitrites, thiocyanates and some glycosides (12). Hence these animals needed an efficient thyroid gland as reservoir of iodine. Therefore....

Keywords: antioxidant, evolution, iodide, iodine deficiency, selenium, thyroid

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Evolution of dietary antioxidants: role of iodine.

Evolution of dietary antioxidants: role of iodine.
Venturi S, Venturi M
Lecture. Feb 6, 2007


The authors review the role of inorganic and organic forms of iodine as an antioxidant in evolution of plants and animals.

Iodine is one of the most abundant electron-rich essential element in the diet of marine and terrestrial organisms. It is transported from the diet to the cells via iodide transporters. Iodide, which acts as a primitive electron-donor through peroxidase enzymes, seems to have an ancestral antioxidant function in all iodide-concentrating cells from primitive marine algae to more recent terrestrial vertebrates. Thyroxine and iodothyronines have an antioxidant activity too and, through deiodinase enzymes, are donors of iodides and indirectly of electrons.

Thyroid cells phylogenetically derived from primitive gastroenteric cells, which during evolution of vertebrates migrated and specialized in uptake and storage of iodo-compounds in a new follicular “thyroidal” structure, for a better adaptation to iodine-deficient terrestrial environment. Finally, some animal and human chronic diseases, such as cancer and cardiovascular diseases, favored by dietary antioxidant deficiency, are briefly discussed.

Keywords: antioxidants, antioxidant evolution, evolution, iodine, iodide, thyroxine

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Read more / les mer... (Word.doc from Iodineresearch.com)

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Evolution of dietary antioxidant defences.

Evolution of dietary antioxidant defences.
Venturi S. and Venturi M.
European Epi-Marker, 2007 Vol.11, 3 :1-12

SUMMARY. The evolution of oxygen-producing cells was probably one of the most significant events in the history of life. Protective endogenous antioxidant enzymes and exogenous dietary antioxidants (as Selenium, Iodine, etc.) helped to prevent oxidative stress. Iodide, which acts as a primitive electron-donor through peroxidase enzymes, seems to have an ancestral antioxidant function in all iodide-concentrating cells from primitive marine algae to more recent terrestrial vertebrates. When about 500 million years ago plants and animals began to transfer from the sea to rivers and land, environmental iodine-deficiency was a challenge to the evolution of terrestrial life. New endogenous antioxidants appeared in plants as ascorbic acid, polyfenols, carotenoids, flavonoids. A few of these appeared recently, about 200-50 million years ago in fruits and flowers of angiosperm plants. In the wide range of antioxidants, we hypothesise an “evolutionary hierarchy”, where the most ancient antioxidants might be more essential than the modern ones in the developing stages of animal and human organisms.

Keywords: antioxidants, ascorbic acid, carotenoids, flavonoids, evolution, iodine, selenium

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Iodine, thymus and immunity.

Iodine, thymus and immunity.
Venturi S, Venturi M
Nutrition, 2009; 25 (9) : 977-9

The United Nations nutrition policy papers [1,2], Food and Nutrition Board and Institute of Medicine [3], Dunn [4], Dunn and Delange [5] of the International Council for the Control of Iodine Deficiency Disorders reported that extrathyroidal iodine has an important action on the immune system. The high iodide concentration of thymus provides the anatomic rationale for this role of iodine in the immune system [6,7] (Fig. 1)

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Role of iodine in delayed immune response.

In this letter to the Israel Journal of Medical Sciences, the authors explain that in order to study the relationship between iodine intake and immune response they studied a population of 607 children, aged 6 to 10 years, living in an area where goitre was endemic. 48% of these children had a goitre. 215 of the children took Lugol’s solution (2 drops per week) for 8 months, and the remaining 392 did not. Immune response was assessed by means of skin testing with tetanus toxoid. If the diameter of the induration was at least 5 mm the response was classed as positive. Diameter of induration was significantly larger among those who had taken iodine than in those who did not. The authors conclude that adequate iodine intake is necessary for a normal delayed immune response.


Role of iodine in delayed immune response. [Iodine and delayed immunity].
[Article in Italian]
Marani L, Venturi S.
Minerva Med. 1986 May 7;77(19):805-9.

Abstract. Iodine was and is sometimes used therapeutically in various pathologies where the immune mechanism is known to play a dominant role. It has in fact been administered to patients with tubercular granulomatous, lepromatous, syphilitic and mycotic lesions where it facilitates cure. This effect does not depend on iodine's action on the micro-organism responsible. Iodine may also be used in Villanova-Panol Panniculitis, in erythema nodosum, in nodular vasculitis, erythema multiforme and Sweet's syndrome.

Oral iodine is also very effective in the lymphatic-cutaneous form of sporotrichosis. In order to establish a relationship between dietary iodine and immune response, 607 infants residing in an area of endemic goitre were studied: 215 were given Lugol solution (2 drops a week for about 8 months) and 392 not.

The immune response was assessed by the skin test method using tetanic toxoid and a clear correlation was shown between this and lymphocyte stimulation and monocytic chemotaxis tests. The test was considered positive when an infiltration of at least 5 mm in diameter was shown after 48 hours (in the U.S. 80% of paediatric cases aged 2-10 years old were positive).

A significant difference was noted in the average diameter of the infiltrations after the tetanic toxoid skin test in the two groups considered (P less than 0.001). The results appear to indicate that an adequate iodine intake is necessary for normal retarded immune response. The molecular mechanism by which iodine increases immune response is still to be decided.

Source: Pubmed (Full text article not yet found)

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Iodine in evolution of salivary glands and in oral health.
Iodine in evolution of salivary glands and in oral health. (2)

Iodine in evolution of salivary glands and in oral health. (2005)
S. Venturi and M. Venturi
Lecture held at the “Thyroid Club” Annual Meeting of Bologna University, Febr.16, 2005

INTRODUCTION. Iodine (I) is the richest in electrons of the required elements in the animal diet, and as iodide (I-) enters into the cells. Inorganic iodide is necessary for all living animal cells, but only the vertebrates have the thyroid gland and its iodinated hormones.

In humans, the total amount of iodine is about 25-50 mg. About 50-70 % of total iodine is non-hormonal and it is concentrated in extra-thyroidal tissues, where its biological role is still unknown. In 1985, Venturi has hypothesized that iodide might have an ancestral antioxidant function in all I-concentrating cells from primitive marine algae to more recent terrestrial vertebrates [1-5 ]. In these cells iodide acts as an electron donor in the presence of H2O2 and peroxidases. The remaining iodine atom readily iodinates tyrosine, histidine or certain specific lipids, and so, neutralizes its own oxidant power.

Keywords: evolution, iodine, antioxidant, apoptosis, oral pathology, salivary glands

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Iodine in evolution of salivary glands and in oral health. (2) (2009)
S. Venturi and M. Venturi
Nutr Health. 2009;20(2):119-34.

ABSTRACT. The authors hypothesized that dietary deficiency or excess of iodine (I) has an important role in oral mucosa and in salivary glands physiology. Salivary glands derived from primitive Iodine-concentrating oral cells which, during embryogenesis, migrated and specialized in secretion of saliva and iodine.

Gastro-salivary clearance and secretions of iodides are a considerable part of “gastro-intestinal cycle of iodides”, which constitutes about 23% of iodides pool in the human body. Salivary glands, stomach and thyroid share I-concentrating ability by sodium iodide symporter (NIS) and peroxidase activity, which transfers electrons from iodides to the oxygen of hydrogen peroxide and so protects the cells from peroxidation.

Iodide seems to have an ancestral antioxidant function in all Iodine-concentrating organisms from primitive marine algae to more recent terrestrial vertebrates. The high Iodine-concentration of thymus supports the important role of iodine in the immune system and in the oral immune defence.

In Europe and in the world, Iodine-deficiency is present in a large part of the population. The authors suggest that the trophic, antioxidant and apoptosis-inductor actions and the presumed anti-tumour activity of iodides might be important for prevention of oral and salivary glands diseases, as for some other extrathyroidal pathologies.

FOREWORD. In the 1930s a correlation between malnutrition and oral health was reported, and, as cited by Weston A. Price (1939), some researchers have also hypothesized the specific correlation between Iodine-deficient goitre and dental caries (Hardgrove, 1939).

Price, in his famous world investigation "Nutrition and Physical Degeneration: A Comparison of Primitive and Modern Diets and Their Effects" (1939), mentioned that "in fish and sea food were essential trace-elements such as iodine, copper, manganese and special vitamins, which were very important for the prevention of health problems and tooth decay" in many coastal populations.

The aim of our study is to search for the pathophysiological correlation between these early nutritional studies and more recent (biochemical, autoradiographical and epidemiological) data regarding the correlation between dietary iodine and oral and salivary glands health.

Keywords: antioxidants; evolution; iodine; oral, dental and salivary pathologies

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Thyroid hormone, iodine and human brain evolution.

Thyroid hormone, iodine and human brain evolution.
Venturi S. and Bégin M. E.
Chapter of book: "Environmental Influences on Human Brain Evolution"
by: Cunnane S. and Stewart K. Publisher: John Wiley, 2010. ISBN: 9780470452684

INTRODUCTION: Evolution of the hominin lineage is marked by progressive brain expansion and complexity concomitant with coordinated changes in other morphological and behavioral traits that characterize speciation events. In addition to gene variation, changes in climate, habitat, and diet are well-recognized environmental stimuli for evolutionary change. Iodine is an
environmental stimulus to which living organisms react, a point particularly evident in amphibian metamorphosis and potentially also in hominin evolution.

In toto, selection pressures effecting evolutionary change involve biological mechanisms permitting adaptation and evolution under changing environmental conditions. A common biological control mechanism could potentially coordinate a suite of physiological, morphological, and behavioral changes as important as brain evolution. We contend here that such a mechanism was hormonal and that thyroid hormone and iodine were pivotal components of such a mechanism.

The principal fossil sites of hominins correlated in space and time with volcanic and fissural local or nearby iodine sources (Borensztejn, 2005). In vertebrates, iodine is incorporated into thyroid hormone in the thyroid gland. Crockford (2003, 2008) provided solid evidence that changing thyroid function, specifically rhythms of thyroid hormone secretion, is crucial for speciation events taking place over decades.

The same thyroid hormone mechanism can be applied to the process of humanizing australopithecines. Here, we postulate a link between thyroid function, iodine, and evolutionary changes as they apply to the evolution of hominins and, more specifically, the large brain of Homo sapiens.

We emphasize changes in habitat and the connection between enhanced dietary availability of iodine, selenium, and polyunsaturated fatty acids (ikke flerumættede vegetabilske olier man spiser, men dem kroppen selv syntetiserer af fortrinsvis kostens animalske - æg, fuldfede mælkeprodukter, fisk m.v. - Omega-3'er/red.) as brain-selective nutrients necessary for thyroid function and hominin brain expansion.

Source: Environmental Influences on Human Brain Evolution (Book)

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