The conventional view is that obesity is the result of eating too much and/or not being active enough. I don’t quite subscribe to this view myself, as I see body weight as the result of a complex interplay between a variety of factors including the form calories come in the diet and hormonal factors. One key hormone here is insulin – the chief hormone responsible for the accumulation of fat in the fat cells. Get insulin levels down and you have a pretty decent chance of losing weight.
Other key hormones that play a part in body weight maintenance include those hormones secreted by the thyroid gland. The most plentiful thyroid hormone is thyroxine (also known as T4). Thyroxine, essentially, stimulates the metabolism. Some of it, in health, is converted into a related hormone known as lio-thyronine (T3) that is more metabolically active. Should the body be deficient in thyroid hormone and/or the tissues be resistant to thyroid hormone (this latter idea I controversial) then ‘hypothyroidism’ (low thyroid function) is the result.
Hypothyroidism can bring with it many different signs and symptoms, but some of the more common include weight gain, fatigue, low mood/depression, dry skin, dry hair, constipation, sensitivity to cold and cold extremities. I’ve found excess weight in individuals with low thyroid function often to be quite resistant to eating right. Many individuals with low thyroid function feel as though their weight is ‘stuck’ somehow.
I was thinking about this today while reading this health story on the BBC website which informs us that the majority (almost 70 per cent) of teenage girls in the UK are deficient in the nutrient iodine. The relevance of this to thyroid function is that iodine is a critical nutrient for proper functioning of the thyroid and production of thyroid hormone. Iodine deficiency is well known to cause enlargement of the thyroid (known as a ‘goitre’).
I remember learning in medical school that goitres were common in places far from the sea where little iodine-rich foodstuffs (such as fish and seafood) are consumed in general terms. This concept came flooding back to me some years ago when I was lecturing in the US and was staying in a hotel which was also inhabited by teenage girls from a (I think) girl guide like organisation based somewhere in the mid-west in the US. I remember remarking to a colleague that every single one of these girls appeared to have a goitre.
If iodine deficiency is so common, could it be contributing to the ‘obesity epidemic’? We may not know the answer to that question for sure, but I think it’s fair to say iodine deficiency will not be helping. And anything that impacts of thyroid function won’t just impact on weight, either, remember. The BBC report makes the point that iodine deficiency can impair brain development in the foetus too.
Ensuring adequate iodine intake does appear to be a matter of considerable importance, particularly for women of child-bearing age. I found what looks like a useful resource on-line for more information about this in the form of the International Council for the Control of Iodine Deficiency Disorders. This website has a useful ‘frequently asked questions’ section which gives advice on several relevant issues including recommended daily intakes and potential iodine sources. It should perhaps be borne in mind that vegetarians and vegans are at a significantly increased risk of eating a diet deficient in iodine [2,3].
References:
1. Vanderpump M, et al. Assessment of the UK iodine status: a National Survey. Endocrine Abstracts 2011;25 OC3.8
2. Remer T, et al. Increased risk of iodine deficiency with vegetarian nutrition. Br J Nutr. 1999;81(1):45-9.
3. Krajcovicová-Kudlácková M, et al. Iodine deficiency in vegetarians and vegans. Ann Nutr Metab. 2003;47(5):183-5.
Iodine and selenium work together. Supplementation of only one of them could cause more harm than good in coutries that are deficient in both.
http://www.ncbi.nlm.nih.gov/pubmed/8427203
http://www.ncbi.nlm.nih.gov/pubmed/16484530
http://www.ncbi.nlm.nih.gov/pubmed/2045471
And, UK is apparently deficient in selenium too:
http://www.ncbi.nlm.nih.gov/pubmed/16672078
Selenium deficiency is probably the cause of increase of Hashimoto’s in countries that began to put iodine in table salt.
In the US, almost all salt is iodised, but that doesn’t seem to be the case in the UK. Anyone know why?
Penny
I don’t know the answer to your question, but it occurs that naturally, iodine deficiency tends to be more commin in regions far from the sea. The UK is a relatively small island in comparison to the US, and maybe many more are at risk of iodine deficiency. Just a thought.
When training to be an aromatherapist one of the older lecturers (a mine of information on ‘tests’ – eg candida or iodine) used to say paint some tincture of iodine on the inside of the thigh or upper arm before going to bed. If it was gone in the morning then you needed to check your iodine. If the stain was still there you were ok.
Penny – please read this article: http://www.healthiertalk.com/health-dangers-table-salt-3743, because it explains why ‘table salt’ is iodised, while the more natural sea and himalayan salts aren’t!
John,
Have you any thoughts on kelp tablets? Mine contain “iodine(as kelp)” 225 mcg, and kelp (Laminaria digitata)” 41 mg. The tablets have a pleasantly marine smell, and are very cheap.
I hate to be the one to point out that simply taking iodine with or without selenium is not the answer, and having doc’s ONLY testing TSH is not the answer either. Did you know the TSH range has changed in the USA? I have a multi nodular goitre, and am super sensitive to any iodine supplemets like kelp etc. I am also super sensitive to contrast used in CT scans. I (symptom wise) range from hypo to hyper, but give me iodine and I am loopy, sick, hyper, palpitations etc etc etc…. it is not a one size fits all answer, especially if you have been iodine deplete for a long time.
I take a kelp supplement and it really does
help my general health and my energy is
really good. I eat Mushrooms and Brazil
nuts for selenium. I am also certain
that many peoples problems are caused in the
intestines where food is not being absorbed properly. The problems caused by this are far reaching
and probably why so many peoples health is badly compromised.
I thought that iodine was found in fast food in great quantities, but apparently not. On the other hand, the U.S. doesn’t seem to have a problem with insufficient iodine…
http://www.endocrinetoday.com/view.aspx?rid=63542
As a medical herbalist I treat here in Canada both Hyper and Hypo thyroidism although the latter is more common. One of the main reasons apart from a lack of iodine is the high processed/wheat based diet consumed in the populations ( especially by teenagers ). Due to the modern processing of wheat etc it becomes it is very high in bromine which binds to and depletes iodine in the body making the situation worse when iodine containing foods are rarely consumed eg fish.
hard to believe, that nobody has mentioned soy yet! 🙂 it’s UBIQUITOUS in processed food in the US, and a potent goitrogen. then, those cruciferous vegetables that everyone thinks are so healthy are, as well. lots of fruits, too. i strongly recommend Chris Masterjohn’s writings on the subject.