His research revealed that 74 per cent of parents know nothing about guidelines advising that children under the age of five are given vitamin D supplements.
More worryingly, more than half of healthcare professionals lack awareness.
Many wrongly believe that rickets - which softens the bone and can lead to skeletal deformities - is a disease of the past. Though common in Victorian times and up to the 1930s, it was all but eradicated with vitamin D supplements by the 1940s.
But, unlike other Western countries, Britain stopped these supplements in the 1950s because of fears that too much vitamin D could be harmful.
In a TV interview Dr Jacobs said this had been a "major mistake".
"We see about one case of rickets a month in our hospital, but that's the very severe end of the disease," the Daily Express quoted him as saying.
"There are many other children who have less severe problems - muscle weakness, delay in walking, bone pains - and research indicates that in many parts of the country the majority of children have a low level of vitamin D.
"It's really only over the past 10 years or so that I've noticed children with vitamin D deficiency and still I would say the majority of doctors, health visitors, midwives, nurses, are not aware enough," he said.
We get most of our vitamin D from sunlight, but it is also found in foods like cod liver oil, oily fish and eggs.
Government advice recommends vitamin D supplements for pregnant and breastfeeding women, children under five, and the over-65s.
But Dr Jacobs says the 400 units a day recommended for pregnant women may be far from enough.
A US study suggested 4,000 units a day.
Chief medical officer Professor Dame Sally Davies said the Government has ordered a review of the current dietary recommendations on vitamin D.