Too Much of a Good Thing - Iodine: 1 mg/day + Can be Bad for You, But the Dangers are as Individual as the Benefits

Seafood is an excellent source of iodine, but many people get most of their iodine from iodized table salt.

I assume you would have expected me to forget that I promised to do my very best to turn the "too much of a good thing" article on selenium I wrote a week ago into a series, right? Well, you obviously don't know me well enough, then, because here's installment #2 of this new series. One that is closely related to #1, but was significantly more difficult to write.

Why's that? Well, if you took a look at the literature discussing the effects of iodine supplementation on thyroid function, you'd know why it was ... well, "complicated" and not exactly unambigous to say the least.

Learn more about your thyroid, T3, and T4 at the SuppVersity

Green tea messes w/ your thyroid hormones

TSH alone is not a good measure of thyroid health

Fructose prevents decline of T3 while dieting

T2 has thyroid-suppressing ef-fects as T3 & T4

Dieting makes you "hypothyroid" - temporarily

Levothyroxine may not be enough →T4+T3?

In view of the fact that it would go beyond the scope of any single article to discuss the detailed effects of iodine and iodine supplements in the various thyroid disease states, I will focus solely on the beneficial and detrimental effects of iodine in more or less healthy individuals. Furthermore, I will not go into details as far as...

• 

  Table 1: The spectrum of iodine deficiency disorders - click to see all (Delange. 1994)

  the important role of iodine in brain and general physical development and the ~30% increase in iodine requirements in pregnant women (Delange. 2000; Zimmermann. 2004 & 2011),
• the role of iodine in psychiatric disease (Hetzel. 2000), and
• the influence of (inorganic) iodine in the environment on human / general mammalian health (Fuge. 1987)

are concerned. What I would like to mention, at least, is the often-cited role of iodine in breast cancer, because the purported protective effect of iodine from supplements or food (Cann. 2000; Funahashi. 2001) is one of the reasons many women consume iodine supplements in dosages that could be more of a threat than a blessing for their health. That's bad news in view of the fact that the "evidence" of breast cancer protective effects is still in the hypothetical state and "rigorous retrospective and prospective studies are needed to confirm this hypothesis" (Cann. 2000).

In the subjects who received more than 1mg of supplemental iodine thyroid size & function was reduced in less than 4 weeks (Sang. 2012).

So what's the safe upper intake limit? I would be hesitant to give a one-size-fits it all limit, because in some people even little more than the RDA may be a problem. According to a 2012 study from the Tianjin Medical University subclinical hypothyroidism in the form of decreased thyroid volumes and TSH levels can occur with as little of 400mcg/day, i.e. 0.4mg/day, of supplemental iodine and a total iodine intake of 800 mcg/day (Sang. 2012). In view of the fact that it took up 500-2000mcg/day to induce a similar hypothyroid state in almost 50% of the subjects, I can only repeat that there's no "one-size-fits-it-all cut-off" for iodine.

Things we can say about iodine that are above all relevant for both, men and women, is that it is essential for normal thyroid function. Just as it is the case for selenium (discussed in the last installment of this series), though, the effects of supplemental iodine on thyroid function are far from being conclusive. While a lack of iodine will force the thyroid to increase it's efficacy by - eventually - developing goiterous growth, the dietary and even more so the supplemental ingestion of copious amounts of iodine (>1mg) do something most people won't expect: They reduce the function of the thyroid glands.

Figure 1: On a population-based study, high(er) iodine intakes are associated with higher TSH levels and thus reduced thyroid function, while high intakes are associated with increased TSH and reduced thyroid fct. (Laurberg. 1998).

It is thus not surprising that populations with low and high iodine intake tend to develop opposite thyroid disorders with

• goiter and thyroid hyperfunction being more prevalent among populations with low(er) iodine intakes, and 
• impaired thyroid function (=subclinical and clinical hypothyroidism) being more prevalent among populations with relatively high iodine intakes (Lauerberg. 1998). 

This does not mean, that "half-deficient" intakes were best, even though there's evidence that a mild = non-goitrogenic iodine deficiency partly protects against autoimmune thyroid disease (Laurberg. 1998). In that US scientists warn that it is not sure, in how many cases the iodine induced reduction in thyroid function "may result from the adverse effect of excess iodine on thyroid function in persons with underlying thyroid disease such as Hashimoto’s thyroiditis, history of subacute thyroiditis, or silent postpartum lymphocytic thyroiditis" (Hollowell. 2002).

The Wolff-Chaikoff effect, a supposedly transient reduction in thyroid function occurs in response to increases in iodine intake and is mediated by a decrease intrathyroidal inorganic iodine uptake into the thyroid (it shuts off) by down regulation of the sodium iodine symporter (NIS). The effect is also supposed to save your thyroid from the assault of radioactive iodine particles in the case of a fallout. Therefore the same 1mg+ iodine tablets people consider a "health supplement" these days were considered a fallout emergency medication during Cold War (Zanzonico. 2000).

It is thus all the more important to take the little experimental evidence there is into consideration. In that, the often-seen drops in thyroid function in response to the ingestion of large quantities of iodine are often ascribed to the so-called Wolff-Chaikoff which is supposed to reduce the thyroid function for no longer than a few a days and then, through the so-called "escape" phenomenon, the organification of intrathyroidal iodide resumes and the normal synthesis of thyroxine (T4) and triiodothyronine (T3) returns (Markou. 2001). Now, the problem is: The phenomenon is not always as short-lived as it is supposed to be

Table 2: Taking high amounts of iodine can significantly reduce thyroid function or induce goiter. Specifically in the subgroups of the population mentioed above (Roti. 2000)

"in a few apparently normal individuals, in newborns and fetuses, in some patients with chronic systemic diseases, euthyroid patients with autoimmune thyroiditis, and Graves' disease patients previously treated with radioimmunoassay (RAI), surgery or antithyroid drugs, the escape from the inhibitory effect of large doses of iodides is not achieved and clinical or subclinical hypothyroidism ensues [and may require temporary or permanent treatment with thyroid medications]" (Markou. 2001). 

Even if you believe you know you don't suffer from any of the aforementioned thyroid problems taking 10mg or more of iodine may be likened to Russian Thyroid Roulette, because it always entails the risk of iodide-induced hypothyroidism. Usually the hypothyroidism is transient and regresses within 2-3 weeks after iodide withdrawal, but as Markou et al. highlight there's a small subgroup of patients who develop transient iodine-induced hypothyroidism that must be followed long term thereafter because many will develop permanent primary hypothyroidism.

Figure 2: People with a previous history of painful subacute thyroiditis (SAT) are highly susceptible to the hypothyroid effects of 300mg/day iodine compared to people who had surgery for benign thyroid nodules (Roti. 1990).

Overall, it should be noted, though that the human body is pretty good at managing high intakes of iodine. While iodine-induced hypothyroidism was also reported in patients with no apparent thyroid disease the number of scientifically verified reports like the mild reversible hypothyroidism that was observed in elderly patients consuming iodinated glycerol by Drinka et al. (1998) or the two Japanese patients with anorexia nervosa developed iodine-induced hypothyroidism after they had consumped of large quantities of OshaberiKombu, a Japanese food that is extensively consumed on lowe energy diets and contains approximately 13.4 mg of iodine per 100g (Matsubayashi. 1998).

All in all the aforementioned examples are yet the exception to the rule. A rule which is evidenced in studies like Markou et al. (2000), in which the authors administered 80 mg potassium iodide (which is also the form of "iodine" in Lugol's solution) to 30 normal children 8 to 14 years old for 3 months and found that none developed overt or subclinical hypothyroidism. That does not mean that the iodine was without effect, but what the scientists observed was the expected transient elevation in serum TSH values (5–8 mU/L) as a result of the Wolff-Chaikoff effect. An effect that abated without further medical intervention on part of the researchers after 3-4 weeks when the TSH returned to normal levels despite the continuation of iodide treatment (Markou. 2000).

So what's the verdict? While it is possible to consume "too much of a good thing" for iodine, it is still not clear (a) how much too much is and (b) for whom this really is a problem. Assuming that you already have thyroid issues or you realize that something is wrong with your TSH, T3 or T4 values after starting to supplement with iodine, stop taking it - the evidence that there are real benefits of consuming iodine in the milligram-to-gram range on a daily basis is quasi non-existent, anyways and evidence of a linear or predictable positive relationship between the amount of iodine you consume and your metabolic rate is as non-existent as proven beneficial effects on the gut microbiome, iodine's ability to "flush out toxins" or the "potent anti-oxidant effects" you can read about on the Internet (in fact, high doses are pro-oxidant and may even have necrotic effects, meaning that the will kill cells - good or bad | Many. 1992; Denef. 1996).

Too Much of a Good Thing - Selenium: Little More Than in Many 'Multis' Can Trigger Subclinical Hypothyroidism, Less Cuts 13% Body Fat | more

That being said, the supply of iodine in the US diet is generally sufficient (Caldwell. 2011), only those groups who are unfortunately also most likely to get too little of other good stuff, i.e. those parts of the population who eat the most messed up diets appear at a small risk of not getting enough iodine on a daily basis. If you have kids or are planning to have kids, though, you may still want to screen your diet for adequate intakes which would be 90 mcg/day for children, 150 mcg/day for adults and 220 mcg/day (but not more than 300-400mcg) for pregnant and 290 mcg/day for lactating/breastfeeding women | Comment on Facebook!

References:

• Cann, Stephen A., Johannes P. van Netten, and Christiaan van Netten. "Hypothesis: iodine, selenium and the development of breast cancer." Cancer Causes & Control 11.2 (2000): 121-127.
• Caldwell, Kathleen L., et al. "Iodine status of the US population, National Health and Nutrition Examination Survey, 2005–2006 and 2007–2008." Thyroid 21.4 (2011): 419-427.
• Delange, François. "The disorders induced by iodine deficiency." Thyroid 4.1 (1994): 107-128.
• Delange, Francois. "The role of iodine in brain development." Proceedings of the nutrition society 59.01 (2000): 75-79.
• Denef, Jean-François, Marie-Christine Many, and M. F. van Den Hove. "Iodine-induced thyroid inhibition and cell necrosis: two consequences of the same free-radical mediated mechanism?." Molecular and cellular endocrinology 121.1 (1996): 101-103.
• Drinka, Paul J., and Wolfram E. Nolten. "Effects of iodinated glycerol on thyroid function studies in elderly nursing home residents." Journal of the American Geriatrics Society 36.10 (1988): 911-913.
• Fuge, R. "Iodine in the environment: its distribution and relationship to human health." Trace substances in environmental health-XXI. 1987.
• Funahashi, Hiroomi, et al. "Seaweed prevents breast cancer?." Cancer Science 92.5 (2001): 483-487.
• Hetzel, Basil S. "Iodine and neuropsychological development." The Journal of nutrition 130.2 (2000): 493S-495S.
• Hollowell, Joseph G., et al. "Serum TSH, T4, and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III)." The Journal of Clinical Endocrinology & Metabolism 87.2 (2002): 489-499.
• Laurberg, Peter, et al. "Iodine intake and the pattern of thyroid disorders: a comparative epidemiological study of thyroid abnormalities in the elderly in Iceland and in Jutland, Denmark." The Journal of Clinical Endocrinology & Metabolism 83.3 (1998): 765-769.
• Many, Marie-Christine, et al. "In vitro study of acute toxic effects of high iodide doses in human thyroid follicles." Endocrinology 131.2 (1992): 621-630.
• Matsubayashi, Sunao, et al. "Iodine-induced hypothyroidism as a result of excessive intake of confectionery made with tangle weed, Kombu, used as a low calorie food during a bulimic period in a patient with anorexia nervosa." Eating and Weight Disorders-Studies on Anorexia, Bulimia and Obesity 3.1 (1998): 50-52.
• Markou, K., et al. "Effects of chronic iodide administration in thyroid function in children and adolescents with a history of transient congenital hypothyroidism." 27th Annual Meeting, Greek Endocrine Association, Nicosia Cyprus. Vol. 82. 2000.
• Roti, Elio, et al. "Iodine-Induced Hypothyroidism in Euthyroid Subjects with a Previous Episode of Subacute Thyroiditis*." The Journal of Clinical Endocrinology & Metabolism 70.6 (1990): 1581-1585.
• Roti, E., and A. G. Vagenakis. "Effect of excess iodide: clinical aspects." Werner and Ingbar’s The Thyroid–Braverman LE and Utiger RD. Ed, Lippincott (2000): 316-329.
• Sang, Zhongna, et al. "Exploration of the safe upper level of iodine intake in euthyroid Chinese adults: a randomized double-blind trial." The American journal of clinical nutrition 95.2 (2012): 367-373.
• Zanzonico, Pat B., and David V. Becker. "Effects of time of administration and dietary iodine levels on potassium iodide (KI) blockade of thyroid irradiation by 131I from radioactive fallout." Health Physics 78.6 (2000): 660-667.
• Zimmermann, M., and F. Delange. "Iodine supplementation of pregnant women in Europe: a review and recommendations." European Journal of Clinical Nutrition 58.7 (2004): 979-984.
• Zimmermann, Michael B. "The role of iodine in human growth and development." Seminars in cell & developmental biology. Vol. 22. No. 6. Academic Press, 2011.

Iodine Induced Reduction in Hepatic Deiodinase Activity Leads to Hypothyrodism and the Accumulation of Liver Fat That May Eventually Pave the Way to Diabesity

While us Westerners think of goitre mostly as a result of iodine deficiency, the Chinese have learned by hard that the opposite is about as likely - goitre in response to iodine in the drinking water is a huge health problem in certain parts of the country (Zheng. 2000)

As colorful as the web may have become, it is still full of paradigmatic black-and-white thinking: The world is either black or white and if you browse the blogosphere, it would appear that iodine would certainly belong to the white part of our world. That in exactly those people who are often referred to as an example of the multitude of beneficial health effects, namely the Japanese, a high intake of iodine has repeatedly been shown to be associated with low thyroid function and even full-blown hypothyroidism, on the other hand, is something you will probably not learn from the tons of unreferenced stuff you'll find on the Internet about how good, if not essential it was for your health to take copious amounts of iodine everyday (about the same amount you would take if the nuclear powerplant next to you exploded to saturate and shut down your thyroid and prevent it from taking up the radioactive iodine).

The Ying and Yang of high and low iodine intake

A recently published rodent study from the Huazhong University of Science and Technology, the Binzhou Medical University and the Shen Zhen Center for Chronic Disease Control, in China (Xia. 2013) does now shed some light onto the underlying mechanisms of the well-known thyroid disrupting effects of the structural backbone of all mammalian thyroid hormones, iodine. While the whole spectrum of disorders of iodine excess includes hypothyroidism, hyperthyroidism, autoimmune thyroiditis,embryo toxicity, and depression of brain development (Guo. 2006; Rose. 2001; Roti. 2001; Yang. 2006) Yun Xia et al. are probably the first to investigate its hazardous effects of iodine excess on the liver.

To this end, the Chinese researchers supplemented rats on a standard diet containing a baseline level of 365μg/kg iodine with different doses of iodine in the form of potassium iodate (KIO3) in the drinking water for 3 months:

"In 2000, the Chinese Nutrition Society stated that the recommended nutrient intake (RNI) of iodine of adults is 150μg/day and the tolerable upper intake level (UL) is 1,000μg/day.
Conversely, intake of iodine at about sixfold of its RNI may induce injury. In addition, many excess iodine animal experimental data indicate that ten times the normal iodine intake in mice for about 3 months can cause damage. Moreover,the results of our previous experiment show that drinking 1.2 mg I/L iodine water for 1 month had no significant effect on serum lipid metabolism, while prolonged exposure for 3 months induced an increase of serum cholesterol." (Xia. 2013)

According to these results, the mice in the study were randomized to receiver either 0, 0.3, 0.6, 1.2, 2.4, and 4.8 mg I/L iodine, corresponding to 0-, 1-, 2-, 4-, 8-, and 16-fold of the adequate/normal iodine intake for 3 months to explore the dose-dependent effect of iodine on hepatic steatosis. In the course of the trial, dood consumption, water consumption of each group, were recorded meticulously and the weight gain of each mouse was recorded daily.

Additionally, another 60 weaning female Balb/c mice were randomly assigned to six groups and given iodine at different levels (0, 0.3, 0.6, 1.2, 2.4, and 4.8 mg I/ml) for 1 month just for
measuring the oxidative stress parameters in serum and liver.

Figure 1: Triglyceride content in liver and serum, as well as SREBP-1c and fatty acid syntethase (FAS) activity after 3 months on diets with additional iodine (Xia. 2013)

While neither food intake, nor water consumption or weight gain differed significantly between the groups (data not shown), a brief glance at the data in figure 1 should suffice to see that there was a dose-dependent increase in hepatic triglyceride levels (=fatty liver disease) that was accompanied by corresponding increases in serum triglyceride, when the liver was clogged up to the max - as it appears to be the case with 8x or 16x higher than normal levels in the diet (for humans that would thus be ~1.6g or 3.2g of potassium iodiate).

Figure 2: Total antioxidant capacity, glutathione peroxidase, SOD, and lipid peroxidation (MDA) after 1 and 3 months expressed relative to untreated control (Xia. 2013)

The fatty acid accumulation in the liver was accompanied by profound changes in total antioxidant and SOD and glutathione status, as well as significant increases in lipid oxidation (as indicated by the +61% and +85% increase in MDA in the groups with the highest intake of supplemental iodine). Contrary to the commonly propagated myth that tons of supplemental iodine would increase the thyroid function these changes were accompanied by profound decreases in D1 deiodinase activity and correspondingly decreased conversion of T4 to T3 (see figure 3).

Figure 3: Changes in thyroid hormone and deiodinase levels; expressed. rel. to control (Xia. 2013)

It should thus not surprise you, that the levels of TSH and T4 in the rodents increased, while those of T3 decreased (no conversion = hypothyroism, no matter how much T4 you got floating around).

Low D1 => Low T3 => fatty liver disease

In fact, the reduced local conversion of T4 to T3, is also behind the accumulation of triglycerides in the liver and blood of the animals, as the

"[r]educed plasma T3 level resulted in the upregulation of SREBP-1c mRNA and FAS mRNA that ultimately led to the accumulation of triglycerides in the liver. [...] Evident hepatic steatosis was observed in mice challenged with 2.4 and 4.8 mg I/L iodine in drinking water. " (Xia. 2013)

As a SuppVersity student you know about the downstream effects, but I guess it makes sense to reiterate them for the newbies: Since the liver plays a, if not the pivotal role in systemic lipid homeostasis the reduced oxidation of triglycerides and the increased storage will sooner or later lead to an increased secretion of triglyceride-rich lipoprotein (VLDL) as a compensatory response by which the liver will desperately try to spread the lipid burdon to other organs and tissues. Overwhelmed with the sudden onslaught of triglyceride laden VLDL particles which are easily oxidized during their voyage through your blood stream, this opens the door to a narrowing of the arteries, cardiovascular disease and stroke.

---

For the majority of you, overtraining and undereating is probably a much greater threat, when it comes to hypothyrodism (learn more about "self-inflicted hypothyrodism"). However, contrary to excess iodine intake that will not clog up your liver and arteries and eventually cause heart disease and stroke.

Bottom line: If we assume based on the available epidemiological data that the general mechanism was identical in human beings, the ingestion of large amounts of iodine which are often touted as a remedy to all sorts of metabolic syndroms may in fact exert the exact opposite effects.

Yet, although I would be cautious about extrapolating the exact cut-off levels, it appears that dietary intakes in the 800µg range and thus 4-6x more than the RDA can still be considered relatively save. So if you are neither taking high dose supplements or living on tons of seaweed, this is probably not much of a concern for most of you. In addition it would warrant investigation if / to which extent the addition of extra selenium would ameliorate these effects. After all, the latter has been shown to have protective effects against iodine intoxication in the very same rodent model in a 2006 study by Xu et al. (Xu. 2006).

References:

• Guo H, Yang X et al. Effect of selenium on thyroid hormone metabolism in filial cerebrum of mice with excessive iodine exposure. Biol Trace Elem Res. 2006; 113:281–295. 
• Rose NR, Bonita R et al. Iodine: an environmental trigger of thyroiditis. Autoimmun Rev. 2002;  1:97–103.
• Roti E, Uberti ED. Iodine excess and hyperthyroidism. Thyroid. 2001;11:493–500.
• Xia Y, Qu W, Zhao LN, Han H, Yang XF, Sun XF, Hao LP, Xu J. Iodine Excess Induces Hepatic Steatosis Through Disturbance of Thyroid Hormone Metabolism Involving Oxidative Stress in BaLB/c Mice. Biol Trace Elem Res. 2013 May 28. 
• Xu, J, Yang, XF., Guo, HL, Hou, XH Liu, LG, & Sun, XF. Selenium supplement alleviated the toxic effects of excessive iodine in mice. Biological trace element research; 2006 111(1-3), 229-238. 
• Yang XF, Xu J et al. Developmental toxic effects of chronic exposure to high doses of iodine in the mouse. Reprod Toxicol. 2006: 22:725–730. 
• Zhao J, Wang P, Shang L, Sullivan KM, van der Haar F, Maberly G. Endemic goiter associated with high iodine intake. Am J Public Health. 2000 Oct;90(10):1633-5. 

Mother's Day Special: 13+ Things Science Has To Tell Us About the First "VIP" in Our Lives

Tell me that's not you! (img. Geeks.Pirillo.com)

While the risk of birth has decreased by 99% in the course of the 20th century, from approximately 850 maternal deaths per 100,000 live births in 1900 to 7.5 in 1982, it is - at least in the US - stagnating ever since (2002 data from the CDC; cf. Chang. 2002). This does not just mean that the Healthy People 2000 objective for maternal mortality of no more than 3.3 maternal deaths per 100,000 live births was not achieved during the twentieth century; it does also mean that your mother - irrespective of your and her age risked her life for you, the very moment you were born. And I am pretty sure that regardless of whether she's had the chance to do just that again, she'd be willing to sacrifice her life, if that would save yours. This alone would be worth cherishing what she has done and hopefully is and will be doing for you on at least one day of the year!

Now, science is a pretty impersonal business and using questionnaires and score-boards to quantify emotions is probably not the appropriate thing to do on Mother's Day. Against that background I have broadened the scoop of today's SuppVersity Mother's Day Special to "all things mother and child" and compiled a potpourri of the very latest and selected older studies on the physical and psychological bond between mother an child and the burdens and rewards of motherhood.

• Married mothers receive the greatest social support, but mothers don't complain (Flowers. 1996) -- As a 1996 paper in the Journal of Divorce & Remarriage reports that the social support in the lives of single, divorced, and married mothers differs significantly.
  
  According to the qualitative and quantitative measures Anita F. Flowers and her colleagues evaluated, the social support network which was defined as the number of people available to the mother for social support and her own perception of the quantity and quality of social support, married mothers differed significantly from single and divorced mothers in both qualitative and quantitative measures of support.
  

  "Married mothers appeared to fare best, reporting larger social support networks and more perceived support, as well as less depression and anxiety." (Flowers. 1996)

  But single and divorced mothers don't complain: All reported similar patterns of emotional support. The patterns of instrumental support, however, varied significantly between married and single mother and those who were divorced, with the latter reporting that they receiving significantly less instrumental support than than the former.
  
  Contrary to the emotional support, which correlated "moderately" with the rates of depression among all mothers, the instrumental support was not significantly correlated with either depression, anxiety, or adjustment to parenthood and lend support to the initially raised notion that the words "Mom, I love you! Thanks for all you're doing for me" are worth more than all the toasters, vacuum cleaners and flowers you may have bought for your mothers in the past ;-)

• A History of Mother's Day: The first celebrations in honor of mothers were held in the spring time in ancient Greece. In the course of the festivities, the Greeks paid tribute to Rhea, the Mother of the Gods. Later, during the 17th century, England honored mothers on "Mothering Sunday," celebrated on the fourth Sunday of Lent. In the United States, Julia Ward Howe is said to have suggested the idea of Mother's Day in 1872. Howe, who wrote the words to the Battle Hymn of the Republic, saw Mother's Day as being dedicated to peace. It is yet Anna Jarvis of Philadelphia who is officially credited with turning this day into an "official" holiday. 
  What children write in their letters on Mother's Day changes with age (Weisz. 1980) -- According to an analysis of the Mother's Day letters from 249  children,  aged  7-17 "references to being granted autonomy and control declined with age"; an observation the scientists interpreted as a sign of a developing understanding for the intent underlying parental behavior.
  

  "She  cooks  the  best  chili  and  she  kisses me every  day on  the  nose."  (April, age 7)

  The same maturation process is probably behind the decline in references to the way mother provide food and physical support to the authors of the analyzed Mother's Day letters.
  

  "She  teaches  me right from wrong, even though it may hurt.  She very heart warming when your down  in  the  blues  [sic]."  (Bill, age  15)

  The references to just  "being there", on the other hand are consistent with person-perception literature "on age increases  in  the use of abstract, covert, and psychological  categories." 

• Iodine is an indispensable nutrient for mothers-to-be and the developing brain of their kids (Hynes. 2013) -- Even a mild iodine deficiency during pregnancy is associated with reduced educational outcomes in the offspring.
  

  "These associations remained significant after adjustment for a range of biological factors (maternal age at birth of child, gestational length at time of birth, gestational age at time of urinary iodine collection, birth weight, and sex). Differences in spelling remained significant after further adjustment for socioeconomic factors (maternal occupation and education)." (Hynes. 2013)

  The data Hynes et al. evaluated was based on the results of a 9-year follow-up of the Gestational Iodine Cohort. According to the detailed analysis, kids that had been born to mother who had urine iodine concentrations (UIC) that were lower than 150µg/l  scored 10.0% worse on spelling, 7.6% worse on grammar, and 5.7% in English-literacy performance tests compared with children whose mothers' UICs were =150 µg/L.

While Crohn's disease, just as a leaky gut and other intestinal disturbances appear to contribute to overall inflammation and consequent visceral fat gain (learn more), Crohn's does not influence the mortality rate of the patients offspring.

• Children born to mothers with Crohn's disease don't have a higher mortality rates (Zugna. 2013) -- While you may get the impression that each and every minimal impairment of maternal health will have highly detrimental effects on the offspring, the effects of Crohn's disease are at least not life-threatening: With 60 deaths per 100,000 person-years in children of mothers with CD, vs. 54 in controls, "[p]arental CD does not seem to influence mortality rate in offspring, which suggests that neither genetic influences of CD nor intrauterine conditions have adverse effects on offspring mortality rate."

• Children born to vaccinated mothers have higher risk of being infected with measles and, possibly, rubella (Waajenborg. 2013) -- What may sound counter-intuitive is actually a pretty logical reaction to the modifying effects of vaccination on the original immune defenses.
  
  Compared to mothers who had not been vaccinated, the "estimated duration of protection by maternal antibodies" among infants in the general population was short: 3.3 months for measles, 2.7 months for mumps, 3.9 months for rubella, and 3.4 months for varicella and thus on average 2 months less than for women from orthodox and unvaccinated communities in the Netherlands.

• Relationship to parents changes with age, but other factors have a greater influence (Kaufman. 1998) -- Gayle Kaufman and Peter Uhlenberg from the The University Of North Carolina At Chapel Hill analyzed the "Effects of Life Course Transitions on the Quality of Relationships between Adult Children and Their Parents" in an eponymous paper from 1998 and observed, that approximately one fifth of relation ships deteriorated with time.

  

  Figure 1: OLS regression of relationship quality with parent at national survey of families and households (Kaufman. 1998)

  A larger baseline effect on the benefial (positive) or negative (negative values) of the mother-son/daughter and father-son/daughter relationship was yet observed the number of siblings and at first maybe surprisingly and not necessarily statistically significant the (partial-) employment status of the parents (see figure 1). Furthermore divorce and declines in parental health lead to deteriorating child-parent relationships and the mother-daughter relationship was significantly better in African American women than in any other ethnicity (0.422 vs. 0.172-0.173 in hispanic and others).

• Mothers who return to work early are more likely to develop depression (Chatterji. 2013) -- According to the results of a recent study from the University of Albany. Specifically,...
  

  "Among mothers of 6-month-old infants, maternal work hours are positively associated with depressive symptoms and parenting stress and negatively associated with self-rated overall health." (Chatterji. 2013)

  As you would expect, this does yet not have negative effects on the mothers' "quality of parenting" - that's how mothers operate: Everything for the kids, nothing for themselves and that's why we are celebrating their day today ;-)

• Kids' inappropriate food intake is mainly a function of "maladaptive parenting practices in mothers" (Moens. 2013) -- I know it's not fair to blame mothers for the obesity of their children, I can hardly think of any mother who does not want only the very best for her kids. Nevertheless, the net outcome of what mothers do and don't do at the dinner table can contribute to children's eating- and weightproblems.
  
  In a pertinent study, researchers from the Department of Developmental, Personality and Social Psychology at the Ghent University. The scientists invited 36 mothers with two children (4-12 y) of which 10 sibling-pairs were discordant for weight status (healthy weight - overweight) to the lab and observed the maternal response and controlling behavior during the meal. Their results showed that the mothers' authariation / permissive behavior had direct influence on the amount the children ate. In particular, ...
  • authoritarian behavior control on part of the mother and higher food intakes (0.51)
  • permissive behavior control on part of the mother and lower food intake (0.52)
  • authoritarian behavior control on part of the mother and less restraint eating (0.66)
  • permissive behavior control on part of the mother and higher dietary restraint (0.65)
  showed statistically significant correlations (corresponding values in brackets). In other words: The harder the mothers pushed, the more the children ate and the less controlled were their eating habits.

• 

  Although ketogenic diets may not be 100% save for pregnant women, many of the fatty staple foods of ketogenic dieters are abundant in choline, a nutrient 25% of the women from high and almost all women from low income countries are deficient. Potential consequences? Birth defects, hampered brain development & more (cf. Zeisel. 2013; learn more about choline)

  Ketogenic diets ain't for mother's to be (Sussmann. 2013) -- Preliminary evidence from rodent studies would suggest that the consumption of a ketogenic diet during pregnancy could result in organ dysfunction and behavioral changes in postnatal life.
  • larger body size early in pregnancy,
  • smaller brain size,
  • smaller body volume later in pregnancy
  • reduced heart sizes
  • smaller thymus
  • enlarged spines, thalamus and midbrain
  I guess most of you will yet be lucky enough to have been born before the keto-hype, anyway. In case you are planning to have a baby though, I personally would not recommend you rely on the stupid saying "mice are no little men".

• Breast-feeding is heart-healthy for mothers (Groer. 2013) -- While you have read numerous times about the superior health effects of breast feeding on the health of your offspring, there is more an more evidence that breastfeeding is also important for the mother's health. While it is obvious that it helps them shed pregnancy weight, a recent from the University of South Florida Colleges of Nursing and Medicine clearly suggests that breastfeading is also good for the heart of the mothers.
  
  Even after adjustment for BMI, the systolic blood pressure (SBP) and heart rate decline in the postpartum period was significantly greater in breastfeeding women compared to matched controls in the who were feeding formula (p<0.05). Other covariates, the scientists evaluated, e.g. family income, stress, marital status, and ethnicity were" not significantly associated with these variables over time." The latter did however influence the stress levels, which were likewise lower in the breast feeding women, but highly depended on the aforementioned confounding factors.

• Children born to better educated mothers have lower risks of depression (Park. 2013) -- While it has long been known that "early-life low socioeconomic position (SEP) increases the risk of adult major depression", the role of maternal eduction is often a better predictor of the offspring's physiological and psychological well-being.
  
  Scientific support for this hitherto non-validated hypothesis comes from a group of researchers who conducted a longitudinal analysis of data from the Canadian National Population Health Survey from 1994/1995 to 2006/2007. In the corresponding paper that's about to be published in an upcoming issue of Social Psychiatry and Psychiatric Epidemiology the authors report that children who are born to mothers with less than secondary school education had a +104% risk of major depressive episodes (MDE) compared to those whose mothers had more education.
  
  Paternal education, on the other hand, was not associated with MDE, at all. Even more astounding is yet that neither adult income, student status, psychosocial stress, and selected common early-life adversities did not influence the association between major depressive episodes and the estimate for maternal education. 

• Transfer of H. pylori from mother to child could be one of the downsides of natural child-birth (Siavoshi. 2013) -- While recent studies did eventually lend credible support to the notion that the bacterial composition of children who are born by Caesarian appear to be less favorable (Turroni. 2012) and could partly explain the higher incidence of type I diabetes (Stene. 2013), a recent study from the University College of Sciences at the  University of Tehran, suggests that natural (=vaginal) child birth entails a greater risk of early colonization with H. pylori.
  

  

  Certain lactobacillus strains can help eridacte H. pylori infections (learn more)

  "A significant correlation was found between the occurrence of H.pylori genes in vaginal yeasts and that in neonates' oral yeasts, occurrence of H.pylori genes in mothers' vaginal yeasts or neonates' oral yeasts, and UBT+ [urea breath test] results in mothers." (Siavoshi. 2013)

  Currently, there is yet a paucicity of evidence suggesting that the higher risk of H.pylori infection entails any future health risks. Nevertheless, a 2009 study from the Peking University Third Hospital is not the only study reporting greater rates of gastric cancer in areas with higher H. pylori prevalence among children in their early teens (Zhang. 2009).  

• "Can you sooth your baby, when he/she is crying"?  (Radesky. 2013) As innocuous as the question may sound, it could be the most important question for a doctor to ask the mother of newborn child. After all, the latest data from a Boston Medical Center and Boston University study clearly shows that inconsolable infant crying quadruples the risk of postpartum depression.
  
  Thus, 5 to 6 weeks postpartum, more than 20 minutes of inconsolable crying per day have more detrimental effects on a mother's psyche than the dreaded infant colics (+100% risk in postpartum depression).

• Well-known / celebrity older mums: Cherie Blair (baby at 45), Madonna (baby at 41), Sarah Brown (wife of Gordon Brown - baby at 40 and 42), J K Rowling (baby at 37 and 39), Emma Thompson (baby at 40), Liz Hurley (baby at 36), Susan Sarandon (baby at 46), Mimi Rogers (baby at 45), Iman (baby at 44), Jerry Hall (baby at 41), Annette Bening (baby at 41), Brooke Shields (baby at 37 and 40),  Geena Davis (baby at 46), Courtney Cox Arquette (baby at almost 40), Helen Hunt (baby at 40), Helen Fielding (baby at 46 and 48), Lowri Turner (baby at 42), Meera Syal (baby at 43), Holly Hunter (twins at 47), Sarah Jessica Parker (baby at 37), Elle Macpherson (baby at 39), Anna Nichol Smith (baby at 38), Salma Hayek (baby at 41), Nicole Kidman (baby at 41), Gwen Stefani (baby at 38), Lisa Marie Presley (twins at 40), Gillian Anderson (baby at 40), Dannii Minogue (baby at 38), Celine Dion (twins at 42), Mariah Carey (baby at 41), complete list at pregnancyover35.
  A mother's age at birth is a significant risk factor for type I diabetes in the offspring (Flood. 1982; Bingley. 2000) -- While the risk for children of older mothers to be born with type I diabetes appears to be particularly pronounced for (late) first-borns, Flood et al. observed in 1982, already, that it type I diabetes was also ore prevalent in late-birth-order siblings.
  
  According to a study by Bingley et al., the risk of type I diabetes increases by 25% (95% confidence interval 17% to 34%) for each five year band of maternal age, so that maternal age at delivery of 45 years or more was associated with a relative risk increase of +211% compared with a maternal age of less than 20 years.

  

  Figure 2: Women by Number of Children Ever Born (US data from the CDC based on stats from 2010)

  The study from the University of Bristol did yet also reveal that paternal age was also associated with a +9% increase for each five year increase in paternal age. Similar to Flood et al. Bingley et al. did also observe a trend for decreasing diabetes risk, for children who came late in the birth order compared to children who were firts-borns to parents in the same age (-15% risk reduction per child born.

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That's it for Mother's Day: Now that you even had a serving of Mother's day gossip, I hope that all of you have something to talk about at the afternoon coffee party at your mother's or your mother-in-law's Mother's Day table. And before I do forget to mention that all the best to all the mother's out there, you are the bests! All of you ;-)

References:

• Chang J, Elam-Evans LD, Berg CJ, Herndon J, Flowers L, Seed KA, Syverson CJ. Pregnancy-related mortality surveillance--United States, 1991--1999. MMWR Surveill Summ. 2003 Feb 21;52(2):1-8.  
• Chatterji P, Markowitz S, Brooks-Gunn J. Effects of early maternal employment on maternal health and well-being. J Popul Econ. 2013 Jan 1;26(1):285-301. 
• Flood TM, Brink SJ, Gleason RE. Increased incidence of type I diabetes in children of older mothers. Diabetes Care. 1982 Nov-Dec;5(6):571-3.
• Flowers AF, Schneider HG, Ludtke HA. Social Support and Adjustment in Mothers with Young Children, Journal of Divorce & Remarriage. 1996. 25:3-4, 69-84
• Groer MW, Jevitt CM, Sahebzamani F, Beckstead JW, Keefe DL. Breastfeeding status and maternal cardiovascular variables across the postpartum. J Womens Health (Larchmt). 2013 May;22(5):453-9. 
• Hynes KL, Otahal P, Hay I, Burgess JR. Mild Iodine Deficiency During Pregnancy Is Associated With Reduced Educational Outcomes in the Offspring: 9-Year Follow-up of the Gestational Iodine Cohort. J Clin Endocrinol Metab. 2013 May;98(5):1954-62. 
• Kaufman G, Uhlenberg P. Effects of Life Course Transitions on the Quality of Relationships between Adult Children and Their Parents. Journal of Marriage and Family. 1998; 60(4): 924-938. 
• Moens E, Braet C, Vandewalle J. Observation of parental functioning at mealtime using a sibling design. Appetite. 2013 Apr 30.  
• Park AL, Fuhrer R, Quesnel-Vallée A. Parents' education and the risk of major depression in early adulthood. Soc Psychiatry Psychiatr Epidemiol. 2013 May 10. 
• Radesky JS, Zuckerman B, Silverstein M, Rivara FP, Barr M, Taylor JA, Lengua LJ, Barr RG. Inconsolable Infant Crying and Maternal Postpartum Depressive Symptoms. Pediatrics. 2013 May 6. 
• Siavoshi F, Taghikhani A, Malekzadeh R, Sarrafnejad A, Kashanian M, Jamal AS, Saniee P, Sadeghi S, Sharifi AH. The Role of Mother's Oral and Vaginal Yeasts in Transmission of Helicobacter Pylori to Neonates. Arch Iran Med. 2013 May;16(5):288-94. 
• Sussman D, van Eede M, Wong MD, Adamson SL, Henkelman M. Effects of a ketogenic diet during pregnancy on embryonic growth in the mouse. BMC Pregnancy Childbirth. 2013 May 8;13(1):109. 
• Stene LC, Gale EA. The prenatal environment and type 1 diabetes. Diabetologia. 2013 May 10.
• Turroni F, Peano C, Pass DA, Foroni E, Severgnini M, Claesson MJ, Kerr C, Hourihane J, Murray D, Fuligni F, Gueimonde M, Margolles A, De Bellis G, O'Toole PW, van Sinderen D, Marchesi JR, Ventura M. Diversity of bifidobacteria within the infant gut microbiota. PLoS One. 2012;7(5):e36957.
• Waaijenborg S, Hahné SJ, Mollema L, Smits GP, Berbers GA, van der Klis FR, de Melker HE, Wallinga J. Waning of Maternal Antibodies Against Measles, Mumps, Rubella, and Varicella in Communities With Contrasting Vaccination Coverage. J Infect Dis. 2013 May 8. 
• Weisz JR. Autonomy, Control, and Other Reasons Why "Mom Is the Greatest": A Content Analysis of Children's Mother's Day Letters. Child Development. 1980; 51(3): 801-807 .
• Zeisel SH. Nutrition in pregnancy: the argument for including a source of choline. Int J Womens Health. 2013 Apr 22;5:193-9. doi: 10.2147/IJWH.S36610. Print 2013.
• Zhang DH, Zhou LY, Lin SR, Ding SG, Huang YH, Gu F, Zhang L, Li Y, Cui RL, Meng LM, Yan XE, Zhang J. Recent changes in the prevalence of Helicobacter pylori infection among children and adults in high- or low-incidence regions of gastric cancer in China. Chin Med J (Engl). 2009 Aug 5;122(15):1759-63.
• Zugna D, Richiardi L, Stephansson O, Cnattingius S, Ludvigsson JF. Mortality Rate in Children Born to Mothers and Fathers With Celiac Disease: A Nationwide Cohort Study. Am J Epidemiol. 2013 Apr 25.