by Ian Wishart
Apart from its work in the developing brain, vitamin D may confer protection in other ways, such as boosting immunity. Studies have shown that pregnant women who catch influenza are more at risk of having a schizophrenic child, therefore a vitamin that reduces your flu risk may also be reducing the risk of mental illness in your unborn child. The most important study to date on the topic reveals catching flu in the first trimester carries a 700% risk increase:
“The risk of schizophrenia was increased 7-fold for influenza exposure during the first trimester. There was no increased risk of schizophrenia with influenza during the second or third trimester. With the use of a broader gestational period of influenza exposure – early to midpregnancy – the risk of schizophrenia was increased 3-fold.”[38]
Mothers should keep in mind, however, that the overall risk of schizophrenia is roughly one in a hundred. As we’ve already seen, the prevalence of autism is usually even higher, up to one in 60 in some countries, so there are very good reasons to ensure vitamin D intake is adequate.
After birth, there are also similar reasons to continue giving your children adequate vitamin D supplements:
“Vitamin D supplementation during the first year of life is associated with a reduced risk of schizophrenia in males. Preventing hypovitaminosis D [low vitamin D] during early life may reduce the incidence of schizophrenia.”[39]
For parents wondering how to get vitamin D supplements into babies or children, the D3 capsules can simply be broken open and the powder mixed with food or milk according to taste.
So how much vitamin D is safe for a pregnant woman to take by supplement? The 400 or 500IU in most pregnancy multivitamins has virtually no effect in scientific trials. One randomised double-blind trial on vitamin D safety in pregnancy has just been completed. It tested hundreds of mothers on 400IU, 2000IU and 4000IU daily supplements, and found that 400IU failed to bring mothers up to the minimum recommended blood level of 80 nmol/L (32 ng/ml).
“Not a single adverse event was attributed to vitamin D supplementation or circulating 25(OH)D levels. It is concluded that vitamin D supplementation of 4000 IU/d for pregnant women is safe and most effective in achieving sufficiency in all women and their neonates regardless of race, whereas the current estimated average requirement (400IU) is comparatively ineffective at achieving adequate circulating 25(OH)D concentrations, especially in African Americans.”[40]
The 4000IU dose succeeded in bringing women up to an average 50ng/ml (125 nmol/L) – about the equivalent of what adults should have with adequate sunlight exposure. Apart from minimising the risk of diseases like some of those listed above, good vitamin D levels in pregnancy appear to assist the placenta in priming baby’s immune system.[41]
Pregnant women with low vitamin D levels are up to four times more likely to end up having a caesarean section rather than a natural birth.[42] A low vitamin D reading is linked to pre-eclampsia and smaller than usual babies.[43]
Human trials on some aspects of vitamin D research are impossible, because of ethics considerations. For example, researchers can use pregnant mice and rats to experiment with – completely starving them of vitamin D on the one hand, or putting them under UV lamps for extended periods of time on the other – to test theories about how vitamin D works. They cannot carry out such controlled studies on pregnant women.
For that reason, when health officials demand more proof by way of “randomized, controlled human trials”, sometimes they are asking for something that can never be done. The research in the nitty-gritty dangerous areas will only ever be observational, after the fact.
Nevertheless, what scientists are discovering in animal studies is that pregnant mice with low vitamin D have bad outcomes in their offspring:[44]
“This animal model is consistent with the fetal origins hypothesis, first articulated by David Barker, which postulates that in utero epigenetic fetal programming, as a result of environmental events during pregnancy, induces specific genes and genomic pathways that control fetal development and subsequent disease risk.[45] This hypothesis initially was applied to adult disorders, Type 2 diabetes mellitus, obesity, and heart disease, but is particularly applicable to asthma, since recurrent wheezing is prevalent in early life and most asthma is diagnosed by age 6 years. We believe that much, if not all, of the fetal origins hypothesis is mediated by vitamin D, as it has a known influence in all of the above named disorders.”
Stripped of its medicalese, the implications are serious: what happens in the womb through a lack of vitamin D may affect a child for the rest of its life.
“The role of vitamin D during pregnancy and its effect on maternal and fetal health is just beginning to be understood,” concludes Carol Wagner in her review. “In the last five years, there has been an explosion of published data concerning the immune effects of vitamin D, yet little is known in this regard about the specific immune effects of vitamin D during pregnancy.
“What is clear, however, is that vitamin D deficiency during pregnancy is rampant throughout the world, including countries such as the United States and Great Britain. While there remains much to be discovered and learned about vitamin D’s effect on the mother and her developing fetus, there is enough evidence to support the premise that deficiency is not healthful for either the mother or fetus.”
An illustration of how much vitamin D plays a role in pregnancy and infancy hit news headlines in 2012:
“The season in which a baby is born apparently influences the risk of developing mental disorders later in life, suggests a large new study. The season of birth may affect everything from eyesight and eating habits to birth defects and personality later in life. Past research has also hinted the season one is born in might affect mental health.”[46]
The source of that story is a study published April 2012, which examined the medical records of 29 million Brits, including a specific 58,000 strong cohort suffering from schizophrenia, bipolar disorder and recurrent depression. What they found is that all the main mental disorders can be pegged back to the season of birth.[47]
Schizophrenia and bipolar, for example, are most often found in British residents born in January, at the peak of the northern winter, and least often found in people born in July, August and September, being the northern summer.
Depression peaks in May – the northern spring – with the fewest cases among people born in November. At first glance that seems to conflict with the vitamin D theory, but researchers say it’s easily explained – developing fetal brains may need vitamin D at different times. Schizophrenia and bipolar patterns might be set in the first trimester which, for babies born in winter, occurs the previous spring when maternal vitamin D has hit rock bottom. Depression, on the other hand, might result from a lack of vitamin D in the second or third trimesters, which for May births coincides with winter.
“SC (Schizophrenia) births showed the most striking seasonality,” reported the study. “These results are also consistent with those of a previous study of English SC patients born between 1921 and 1960 indicating that the season of birth effect is a stable feature of SC.”
The odds of being born in winter for schizophrenia patients were 17% higher than being born in summer. Obviously people who go on to develop mental illness are being born year-round, but if most mothers are clinically deficient or insufficient in vitamin D all the time, then that’s no great surprise. What the study shows is that the northern hemisphere summer gives enough of a vitamin D spike to some mothers to save their children from the increased risk.
Unfortunately a lack of vitamin D during pregnancy is like leaving the house unlocked. There’s no guarantee a burglar is going to pick your house to raid on that particular day, but if he does he’ll find it defenceless. That’s what an increased risk is, it’s not a certainty that fate [in the form of an environmental trigger] will strike you, but an increased possibility. With researchers now suggesting that vitamin D deficiency in the womb and early childhood could account for 44% of schizophr
enia cases, the solution may be in the hands of mothers everywhere.
The British confirmation that mental illness is related to your birth season follows similar studies in the United States that made the same discovery.[48]
More tragically, researchers have found suicide follows the same pattern, with people born in April/May in the northern hemisphere more likely to end their own lives, and people born October/November less likely – very similar to the seasonal spread for Depression. [49]
To think that one vitamin, and whether you get enough of it in your mother’s womb or not, can have such a huge impact on your life, is sobering to say the least.
One area where vitamin D does not have an impact on otherwise-healthy kids is their academic ability. While the power of the vitamin to kickstart the brains of older people, and particularly Alzheimer’s sufferers, is undeniable, new studies have shown it has no such effect on teenagers.
Whether that’s because their bodies are being flooded with other hormones and influences isn’t known. What we do know is that a British study found teens from more advantaged backgrounds had higher vitamin D3 levels (obtainable from sunlight or specific D3 supplements), whereas children from disadvantaged backgrounds tended to have the D2 variety, sourced from food.
When their high school exam results were assessed against their vitamin D levels, there was no difference between the groups.[50]
Keep taking the omega-3 pills, kids.
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[3] “Aortic atherosclerotic disease and stroke,” Kronzon I, Tunick PA. Circulation 2006; 114:63-75; PMID: 16818829; DOI: 10.1161/CIRCULATIONAHA.105.593418
[4] Stöppler MC, Lee D, Kulic D, Peripheral MD. Vascular Disease. MedicineNet.com. http://www.medicinenet.com/peripheral_vascular_disease/article.htm
[5] “Vitamin D is positively associated with sperm motility and increases intracellular calcium in human spermatozoa,” Jensen et al, Human Reproduction (2011) 26 (6): 1307-1317. doi: 10.1093/humrep/der059
[6] “Circulating vitamin D correlates with serum antimüllerian hormone levels in late-reproductive-aged women: Women’s Interagency HIV Study”, Mehri et al, Fertility and Sterility, Volume 98, Issue 1 , Pages 228-234, July 2012
[7] “Vitamin D metabolism, sex hormones and male reproductive function,” Jensen, M, Reproduction May 25, 2012 REP-12-0064
[8] Wehr E, Pilz S, Boehm BO, März W, Obermayer-Pietsch B. Association of vitamin D status
with serum androgen levels in men. Clin Endocrinol(Oxf), 2009 Dec 29.
[9] “Vitamin D and fertility – a systematic review,” Elisabeth Lerchbaum and Barbara Obermayer-Pietsch, Eur J Endocrinol. 2012 May;166(5):765-78. Epub 2012 Jan 24,
http://www.eje-online.org/content/early/2012/01/24/EJE-11-0984.full.pdf
[10] “Vitamin D association with estradiol and progesterone in young women,” Knight et al, Cancer Causes & Control. 2010 Mar;21(3):479-83
[11] “Vitamin D can aid fertility,” by Rebecca Smith, The Telegraph, 11 November 2008
[12] “Effects of 25OHD concentrations on chances of pregnancy and pregnancy outcomes: a cohort study in healthy Danish women,” Mølle et al, European Journal of Clinical Nutrition (2012) 66, 862–868; doi:10.1038/ejcn.2012.18
[13] “Vitamin D and Its Role During Pregnancy in Attaining Optimal Health of Mother and Fetus,” Wagner et al, Nutrients 2012, 4(3), 208-230; doi:10.3390/nu4030208
[14] “Vitamin D and pregnancy: An old problem revisited,” Barrett H, McElduff A, Best Practice & Research, Clinical Endocrinology & Metabolism. 2010 Aug;24(4):527-39.
[15] “Maternal vitamin D status in pregnancy is associated with adiposity in the offspring,” Crozier et al, American Journal of Clinical Nutrition, July 2012, doi: 10.3945/ajcn.112.037473
[16] It may also help adults. A study of women over 65 in the USA found those with lower vitamin D levels had a higher weight gain over the four and a half year trial. See “Associations Between 25-Hydroxyvitamin D and Weight Gain in Elderly Women,” LeBlanc et al, Journal of Women’s Health, online 25 June 2012, doi:10.1089/jwh.2012.3506
[17] “Check vitamin D in adolescents before bariatric surgery,” Clinical Endocrinology News, June 28 2012
[18] “Vitamin D levels and food and environmental allergies in the United States: Results from the National Health and Nutrition Examination Survey 2005-2006,” Sharief et al, Journal of Allergy and Clinical Immunology, Volume 127, Issue 5, May 2011, Pages 1195–1202
[19] “Food allergic infants more likely to have vitamin D insufficiency,” Family Practice News, 22 March 2012, citing Journal of Allergy and Clinical Immunology, 2012; 129[suppl.]:AB141
[20] “Vitamin D and Its Role During Pregnancy in Attaining Optimal Health of Mother and Fetus,” Wagner et al, Nutrients 2012, 4(3), 208-230; doi:10.3390/nu4030208
[21] “Maternal vitamin D status during pregancy and childhood bone mass at 9 years: A longitudinal study”, Javaid et al. Lancet 2006, 367, 36-43
[22] “Serum 25-hydroxyvitamin D and calcium homeostasis in the United Arab Emirates mothers and neonates: A preliminary report,” Dawodu et al. Middle East Paediatr. 1997, 2, 9-12
[23] “Vitamin D deficiency in Iranian mothers and their neonates: A pilot study,” Bassir et al. Acta Paediatr. 2001, 90, 577-579
[24] “High prevalence of vitamin D deficiency among pregnant women and their newborns in northern India,” Sachan et al, Am. J. Clin. Nutr. 2005, 81, 1060-1064
[25] “Vitamin D deficiency in pregnant New Zealand women,” Judkins, A.; Eagleton, C.. N. Z. Med. J. 2006, 119, U2144
[26] High prevalence of hypovitaminosis D in pregnant Japanese women with threatened premature delivery,” Shibata et al. J. Bone Miner. Metab. 2011, 29, 615-620
[27] “High prevalence of vitamin D deficiency in pregnant non-Western women the The Hague, Netherlands,” Van der Meer et al. Am. J. Clin. Nutr. 2006, 84, 350-353
[28] “Vitamin D status during normal pregnancy and postpartum. A longitudinal study in 141 Danish women,” Milman et al. J. Perinat. Med. 2011, 40, 57-61
[29] “Cord Blood Vitamin D Deficiency Is Associated With Respiratory Syncytial Virus Bronchiolitis,” Belderbos et al, Pediatrics Vol. 127 No. 6 June 1, 2011 pp. e1513 -e1520 (doi: 10.1542/peds.2010-3054),
http://pediatrics.aappublications.org/content/127/6/e1513.full
[30] “Neonatal Vitamin D Status and Risk of Schizophrenia – A Population-Based Case-Control Study,” McGrath et al, Arch Gen Psychiatry. 2010;67(9):889-894. doi:10.1001/archgenpsychiatry.2010.110, http://archpsyc.jamanetwork.com/article.aspx?articleid=210878
[31] “Low Vitamin D Linked to Schizophrenia,” Discovery News, 7 Sep, 2010, http://news.discovery.com/human/vitamin-d-schizophrenia.html
[32] If you are worried about possible mental illness in your children, have babies before the age of 25. Studies have shown a 17% increase in schizophrenia risk to children whose fathers are aged 30, rising to double the risk where Dad is 45, and three times the risk where Dad is aged over 50. The fault is thought to lie with spermatogenesis which, coincidentally, has been shown to improve in men with high vitamin D levels. “Advancing paternal age and the risk of schizophrenia,” Malaspina et al, Archives of General Psychiatry, 2001 Apr;58(4):361-7
[33] “The Antecedents of Schizophrenia: A Review of Birth Cohort Studies,” Welham et al, Schizophrenia Bulletin (2009) 35 (3): 603-623. doi: 10.1093/schbul/sbn084 http://schizophreniabulletin.oxfordjournals.org/content/35/3/603.full#ref-77
[34] This Scandinavian discrepancy, which is at odds with studies in other parts of the world, keeps popping up. In a study published August 2012, blood samples from 247,000 Danish citizens were analysed for mortality risk relat
ive to vitamin D. The safest vitamin D levels for Danes appear to be 50-60 nmol/L (20-24 ng/ml). Compared with that bracket, Danes with lower vitamin D levels were 2.1 times more likely to have died, while that U-curve was back with the revelation that Danes with blood vitamin D levels higher than 140 nmol/L (56 ng/ml) were 1.4 times more likely to have died. For Scandinavians, the question has to be asked whether centuries of living in low vitamin D areas has caused micro-evolutionary responses. Are they, for example, more efficient at processing low levels of vitamin D, so that they’re getting more bang from their D buck and don’t need higher levels, or are they less efficient at processing, leaving high serum levels but less biologically-active vitamin D? See “A reverse J-shaped association of all-cause mortality with serum 25-hydroxyvitamin D in general practice, the CopD study,” Durup et al, Journal of Clinical Endocrinology & Metabolism, August 2012, 97(8), doi: 10.1210jc.2012-1176
[35] Black migrants are up to five times more likely to have schizophrenic children, “Schizophrenia and migration: a meta-analysis and review,” Cantor-Graae E, Selten JP. American Journal of Psychiatry, 2005 Jan;162(1):12-24
[36] “Foresight mental capital and wellbeing: discussion paper 12: putative prevention strategies to reduce serious mental illness in migrant and black and minority ethnic groups. London, England,” Kirkbride JB, Jones PB.: Her Majesty’s Stationary Office; 2008;
[37] The “incidence” of schizophrenia is the rate of new diagnoses each year. The “prevalence” is the ratio of people living with the disorder at any given moment in time (total % of sufferers in the community)
[38] “Serologic evidence of prenatal influenza in the etiology of schizophrenia,” Brown et al, Archives of General Psychiatry. 2004 Aug;61(8):774-80