Powerful new evidence about the way that vitamin D can reduce the risk of premature births and boost the health of newborn babies has emerged from an international research conference in Bruges. Delegates were told that mothers who were given ten times the usual dose of vitamin D during pregnancy had their risk of premature birth reduced by half and had fewer small babies.
The findings emerge after evidence, revealed in The Times, that vitamin D — the “sunshine vitamin” — could have a dramatic effect in combating Scotland’s appalling health record. Statistics showing that Scots — particularly in the west — are exposed to less sunshine than those living farther south correlate exactly with higher incidences of heart disease, some cancers and multiple sclerosis. The Times has campaigned to have vitamin D recommended and prescribed as part of a national health programme.
The vitamin’s benefits have been observed previously in uncontrolled studies of pregnant women and babies, but this is the first time they have been found in a scientific trial which met the most stringent criteria for “evidence-based inquiry”. The findings may make it necessary for health departments to revise advice presently given to pregnant and breastfeeding women in the UK.
The investigators, Dr Bruce Hollis and Dr Carol Wagner of the Medical University of South Carolina, Charleston, met rigorous safety tests which were required by the Federal Drug Administration. The study was funded by the National Institutes of Health. The women, who all lived around Charleston, South Carolina, began taking 4,000 IUs per day of vitamin D after their first clinic visit at about three months of pregnancy. (4,000 IUs or international units equals 100 microgms). A control group took 400 IUs,equivalent to the normal recommended dose in the US and UK. The women had their blood and urine tested monthly to ensure calcium and vitamin D levels were within safe limits.
Over the 2½ years of the study thousands of tests were made and monitored by an external safety committee. No test showed any adverse effect of the large dose of vitamin D. The average level of vitamin D in the women’s blood increased by about 50 per cent.
About 600 women took part in the trial which included similar numbers of African Americans, Hispanic Americans and whites. Premature babies born to women taking high doses of vitamin D were reduced by half at both 32 and 37 weeks, and there were also fewer babies who were born “small for dates” — that is smaller than would be expected considering the length of time spent in the womb.
The women had a 25 per cent reduction in infections, particularly respiratory infections such as colds and flu as well as fewer infections of the vagina and the gums. The “core morbidities of pregnancy” were also reduced by 30 per cent in the women who took the high-dose vitamin D.
These included diabetes, raised blood pressure, and pre-eclampsia, an increase in blood pressure and fluid which may, if untreated, cause the death of the mother and/or the baby. Babies getting most vitamin D after birth suffered from fewer colds and less eczema.
The Charleston team is running another trial in breastfeeding women who are taking 6,400 IUs per day, a dose 16 times the amount of vitamin D recommended in the UK. This high dose enables women to make breast milk which has sufficient vitamin D for the baby’s needs, 400 IUs per day.
The American investigations used vitamin D3, the human form of the vitamin which is more potent than the vitamin D2, the plant form present in Abidec, the vitamin mixture usually recommended for babies in the UK.
“I’m telling every pregnant mother I see to take 4,000 IUs and every nursing mother to take 6,400 IUs of vitamin D a day,” said Dr Hollis. “I think it is medical malpractice for obstetricians not to know what the vitamin D level of their patients is. This study will put them on notice.”
Five years ago the UK National Institute of Clinical Excellence told doctors that women in Britain did not need to take vitamin D in pregnancy advice later overruled by the Chief Medical Officer.
BEHIND THE STORY
The normally recommended level of sun exposure in the UK does not produce enough vitamin D, according to a separate study reported at the Bruges meeting (Oliver Gillie writes). Sunlight is the main source of vitamin D in the UK as elsewhere and so advice on sun exposure is crucial for health. Food cannot supply more than 10 per cent of what is needed.
Dr Jackie Berry, and Dr Ann Webb and others from the University of Manchester studied the effect of sunlamp treatment, which simulated summer sun in the UK, on 120 white volunteers who wore only a T-shirt and shorts. The treatments were given three times a week for six weeks in winter when blood levels of vitamin D are low and only 26 per cent of the volunteers obtained optimum blood levels as a result of the treatments.
This new research shows that advice, still given in the UK, that casual exposure of hands and face provides sufficient vitamin D is completely wrong. Revised advice from the Department of Health in December 2007 suggested that pregnant women would get sufficient vitamin D if they exposed shoulders as well as arms and legs. But this too is now shown to be insufficient by the study of simulated “British sunlight”.
To get optimum benefit from sunbathing as many clothes as possible should be removed, or it should be done more often than three times a week, or for longer than 13 minutes a day. All these increases in exposure can be difficult to achieve especially when sunny weather seldom lasts for six consecutive weeks in the UK.
In wintertime in the UK the optimal level of vitamin D can only be obtained by taking a supplement because the sun is too weak. The Standing Committee of European Doctors is preparing a report on vitamin D which is expected to recognise, contrary to advice in the UK, that everyone, apart from young children, needs a vitamin D supplement of at least 1,000 IUs a day and probably 2,000 for full health.
The higher 2000 figure is supported by observational studies of groups of people showing higher levels of vitamin D are associated with a reduced risk of cancer, heart disease and immune system diseases as well as classic bone diseases, but as yet there are relatively few controlled scientific trials of higher doses.
Patients with hip fractures in Boston, in the US, taking 2000 IUs of vitamin D had 60 per cent fewer complications and 90 per cent fewer infections than patients who received a placebo in a double blind randomised trial, the Bruges workshop was told. They were also 40 per cent less likely to be readmitted to hospital, said the study leader Dr Beth Dawson-Hughes of Tufts University, Boston.