Millions of children with autism could unknowingly be suffering key vitamin deficiencies, research today suggested. 

Research has consistently indicated that individuals with this condition are five times more prone to be selective about their food choices and have a reluctance to try unfamiliar foods compared to children developing typically.

But little is still known about the impact of such diets.

Now, scientists from Singapore believe almost 40 per cent of autistic children could be deficient in vitamin D and iron. 

The team of researchers, who evaluated the eating patterns of more than 240 children, uncovered that over 15 percent of those with an iron deficiency had progressed to anemia, a condition where the body does not have sufficient healthy red blood cells to transport adequate oxygen throughout the body.

Experts, who labelled the findings important, urged officials to consider implementing routine nutrition checks for children with autism. 

As reported in the journal Nutrients, the researchers stated: ‘Deficiencies in vitamin D and iron were frequently identified among this group of children with autism.

‘Detecting these deficiencies and seeking the appropriate treatment can lead to enhancements in the health and development of these children.’

Studies have consistently shown individuals with the condition are significantly more likely to be choosy about eating and apprehensive about new foods than their typically developing peers. However, the effects of such dietary habits remain not fully understood.

In their findings, the researchers noted that 36.5 percent of the children, who averaged four years old, were lacking in vitamin D, and 37.7 percent suffered from iron deficiency.

Over a follow up of four years, they also found that age was a factor for low iron levels.

Every additional month of age increased a child’s odds of developing vitamin D deficiency by four per cent.

Older children were more likely to present with iron deficiency anemia. 

But among the picky eaters, ‘there was also no association between age and iron deficiency’, the researchers from the National University Hospital, Singapore, said. 

‘These findings could be related to the common use of formula milk when younger, which is fortified with nutrients including iron, thereby protecting against nutritional deficiencies.’

They acknowledged, however, the study did have limitations, including its small size. 

‘As it was based on children whose caregivers agreed for blood investigations to be performed, these parents could have been more concerned regarding their child’s dietary habits,’ they added. 

A recent study in the Journal of Child Psychology and Psychiatry found autism diagnoses had risen by an ‘exponential’ 787 per cent in 20 years in England 

‘This could have motivated them to proceed with blood investigations.’

If left untreated, vitamin D deficiencies can trigger more serious health issues including bone deformities like rickets.

Other side effects of low vitamin D include muscle pain, bone pain, pins-and-needles in the hands or feet and weakness.

Typically, the NHS says in summer months we should get all the vitamin D we need from sunshine, but in winter months some people need supplements.

Meanwhile, it should be possible to get enough iron through a balanced diet, but some people with low iron need tablets like ferrous fumarate.

Symptoms of low iron also include fatigue, shortness of breath, paler skin than usual and headaches.

It comes as US research earlier this week suggested autism diagnoses in young girls may be flying under the radar because their symptoms are milder than boys.

The findings have prompted concern that girls are missing out on key treatment and therapy that is leaving them prone to other health issues later on.

In England, the number of children seeking help for suspected autism has spiralled to an all-time high in Covid’s wake.  

According to latest NHS figures, almost 130,000 under 18s in England were still awaiting an assessment in December 2024—a six-fold increase on the 20,000 logged in December 2019.

Experts have long warned that young people are facing an ‘invisible crisis’, with a system that has repeatedly failed to keep pace with rising demand.

Autism is not a disease and people have it from the moment they are born, although it may not be spotted until childhood and sometimes much later.

It exists on a spectrum. Some people will be able to lead fully functioning lives with no additional help. Others may need full-time assistance.