British Summertime is officially over and as short days and dreary skies loom, the lack of sunshine can have huge implications for health-especially for little ones. Not getting enough vitamin D, the chief source of which is the sun, is now recognized as a big problem in children, particularly among the under-5s. Rickets (soft and deformed bones caused by vitamin D deficiency) is on the rise, and there's mounting evidence linking low levels of the 'sunshine vitamin' to a raft of other health problems-from allergies and eczema to autism and mental disorders.
Most shocking, it seems that a lack of vitamin D may be involved in sudden infant death syndrome (SIDS)-a leading cause of death in infants aged under 12 months.
The D in SIDS
In 2012, two UK paediatric pathologists made headlines after discovering vitamin D deficiency in a significant number of SIDS cases and suspicious deaths. The findings-made by Dr Irene Scheimberg, at Royal London Hospital in Whitechapel, and Dr Marta Cohen, at Sheffield Children's Hospital-followed Dr Scheimberg's diagnosis in 2009 of congenital rickets in a four-month-old baby whose parents had been accused of shaking him to death.
Chana Al-Alas and Rohan Wray were acquitted of murdering their son, Jayden, after the jury learned that his fractures, supposedly signs of abuse, may have been caused by severe rickets, which his mother also had. Severe vitamin D deficiency can make the bones of infants extremely brittle and easily fractured with little force, Dr Scheimberg said. Jayden's case spurred an investigation into other sudden infant deaths, leading to Dr Scheimberg's uncovering of a D deficiency in a further 30 cases in London alone. In three of them, vitamin D deficiency was the actual cause of death. Meanwhile, in Yorkshire, Dr Cohen found moderate-to-severe levels of D deficiency in 45 children, mostly infants aged under 12 months, who had apparently died of natural causes. 1 Both doctors have since published papers supporting a link between vitamin D deficiency and SIDS. Dr Cohen's study-an analysis of 41 post-mortem cases-came to the conclusion that "a significant proportion of infants and children who died suddenly and unexpectedly had inadequate levels of vitamin D".
Of the 25 unexplained deaths in the study, 76 per cent were lacking in vitamin D. 2 Dr Scheimberg's study of 52 post-mortem cases reported that "severe rickets combined with profound hypocalcaemia [low calcium levels] can cause unexpected death in babies and young children". When it comes to unexplained deaths in 'at-risk' children, vitamin D levels could provide important clues to the cause, her study said. 3 These alarming findings need to be confirmed in larger studies, but they add weight to the recent calls for widespread vitamin D supplementation across the UK, particularly for vulnerable groups like the under-5s. Vitamin D supplements are already recommended for these children (as well as for the elderly and pregnant or breastfeeding women), but research suggests that one in four UK toddlers still has low levels of the vitamin. 4 New figures from the NHS also show that the number of children with rickets has increased more than fourfold over the last 10 years. 5 Children spending more time indoors, and the advice to stay out of the sun to avoid skin cancer are thought to be partly to blame. But not enough vitamin D isn't just bad for bones. Studies are stacking up to show that low levels can put children at risk for a wide range of health problems.
According to a recent Australian study, children living at latitudes with little sunshine and, therefore, low levels of vitamin D are more likely to develop food allergies, as well as the skin condition eczema, compared with children living in areas with more sunshine. The odds of having a peanut allergy were six times greater in the more southerly regions compared with the more northerly ones, the researchers found, while the chances of having eczema doubled.
Egg allergy was also more common in children living in the less sunny regions. 6 Another Australian study discovered that the children of mothers who ate a lot of vitamin- D-rich foods (like fatty fish and eggs) while pregnant were significantly less likely to have allergic conditions like eczema, asthma and hay fever. 7 There's also evidence suggesting that vitamin D deficiency in children is a major predictor of asthma. 8 Psychiatric problems, too, have been linked to low vitamin D levels in children. A study by the Oregon Health & Science University in Portland found that children with severe mental-health disorders, including psychosis, were more likely to be deficient in D compared with mentally healthy children. Overall, 21 per cent of children with severe psychiatric symptoms had levels below the official recommendations, while only 14 per cent of mentally healthy children were D-deficient.
Although these results were not statistically significant, the strongest connection was between vitamin D deficiency and psychotic disorders like schizophrenia, supporting the findings of previous studies. 9 Study author Keith Cheng says the role of vitamin D in brain function and development is still unknown, but what's understood is that vitamin D receptors are sited in various brain cells. "We don't know exactly what happens when those receptor sites aren't active," says Cheng, "but we do know . . . they are there for a reason."
D for diabetes
Other research suggests that not getting enough vitamin D could up the risk of diabetes. In a study in Finland of more than 12,000 babies followed for more than 30 years, the children who
regularly took vitamin D supplements had a lower rate of type 1 diabetes (T1D) than those who did not, while those suspected of having rickets had a threefold greater risk of diabetes. These data also showed that children regularly taking 2,000 IU/day of the vitamin (the recommended dose at the time) had an 80 per cent lower risk of T1D than those who regularly took smaller doses. 10 More recently, researchers in Stockport in the UK pooled the results of five separate studies of the effects of vitamin D supplements in infancy on T1D risk. They found that those given additional vitamin D were roughly 30 per cent less likely to develop T1D later in life than those not supplemented. 11
What dose of D?
These compelling studies add to the evidence in adults suggesting that vitamin D can protect against a range of diseases and conditions like cancer, heart disease and even death. But how
much should a child be getting and what's the best way to get it? As we know, the sun is the best natural source of vitamin D; it's synthesized in the skin on exposure to sunlight. But
sun exposure is not advised for infants aged under six months, and many children over that age are probably not getting enough D this way either, especially in winter.
In the UK, vitamin D supplements are currently recommended for children aged six months to five years (280-340 IU/day), and for pregnant and breastfeeding women (400 IU/day).
But according to some experts like Mike Fischer of the Vitamin D Association, if you follow these guidelines, "your baby is at significant risk of vitamin D deficiency during the first six months
of life". Formula-fed infants get a decent dose of the vitamin, Fischer says, as all infant formulas are enriched with about 400 IU/L of D. Breastfed babies, however, will probably not be getting enough from their mother's milk. In fact, a study of 40 mothers with exclusively breastfed, unsupplemented infants found that two-thirds of the babies were deficient in vitamin D, and an alarming 45 per cent were at risk of rickets. 12 For this reason, the Vitamin D Association recommends that all breastfed babies receive vitamin D3 drops (Carlson for Kids Super Daily D3 Drops or Baby Ddrops, available from most pharmacies and online) that contain 400 IU/day, beginning in the first few weeks of life. 13 Alternatively, breastfeeding can give babies the vitamin D they need, provided the mother takes a high- dose supplement. Studies show that doses up to 15 times the current UK recommended daily intake (400 IU/ day) are needed to produce enough
to transfer from mother to breastfed infant. 14 That's why many experts, including Bruce Hollis, professor of pediatrics at the Medical University of South Carolina in the US, and organizations like the non-profit Vitamin D Council recommend a dose of 4,000-6,000 IU/day for pregnant and breastfeeding women.
As for children over the age of six months and those who aren't breastfed, the recommended dose is also probably too low. The Vitamin D Council thinks infants should be getting up to 1,000 IU/
day of vitamin D, while children and adolescents need 1,000 IU/day/25 lb (11 kg) body weight. Although individual requirements will vary, these guidelines may be useful not just for
preventing vitamin D deficiency, but for helping to fight off a diverse range of other conditions as well.
2 Pediatr Dev Pathol, 2013; 16:
3 Pediatr Dev Pathol, 2014 Jul 14;
Epub ahead of print
6 J Allergy Clin Immunol, 2012; 129:
7 Nutrition, 2014; 30: 1225-41
8 Int Arch Allergy Immunol, 2012;
9 F1000Res, 2013; 2: 159
10 Lancet, 2001; 358: 1500-3
11 Arch Dis Child, 2008; 93: 512-7
12 Mayo Clin Proc, 2013; 88: 1378-87
14 J Hum Lact, 2013; 29: 163-70
Vitamin D2 vs D3
Two types of vitamin D are available over the counter: vitamin D2 (ergocalciferol); and
vitamin D3 (cholecalciferol). Most experts believe that D3 is better and here's why:
It's the most natural form of the vitamin: we synthesize D3 from
sunlight, but we never make D2.
D3 appears to be less toxic than D2.
D3 is more potent, and better for raising and maintaining levels of the
vitamin in the circulation.
D3 keeps its potency better on the shelf than D2.
D3 has been more studied in clinical trials.
1 Dermatol Nurs,
2009; 21: 25-30, 55
The autism connection
A study carried out in Saudi Arabia found that
children with autism have significantly lower levels
of vitamin D in their bloodstreams than non-
autistic children-and the lower the levels, the
higher the scores on the Childhood Autism Rating
Scale of severity.
The study also revealed a possible mechanism
behind the link. The majority (70 per cent)
of children with autism had raised levels of
antibodies that can disrupt neuronal signalling in
the brain. This, in turn, might trigger autistic traits
in genetically susceptible children. Intriguingly, the
study showed that the lower the vitamin D, the
greater the level of antibodies and the worse the
autistic symptoms. 1
1 J Neuroinflammation, 2012; 9: 201