Two thirds of parents admit they're confused about what kids should and shouldn't eat.
And even though 70 per cent of parents know their children should eat five portions of fruit and vegetables per day, 29 per cent say they have no idea why.
Boots Kids Vitamins surveyed 2,000 British parents of children aged 4 to 16 and uncovered the surprising results about nutritional knowledge among parents.
Even though 66 per cent believed they were in the know about vitamins and mineral consumption - with 15 per cent saying they were 'very knowledgeable' - one in five said they didn't know which foods to consume to raise their vitamin D levels.
Boots Kids Vitamins spokesperson Parminder Kaur said: "Brits are more conscious than ever about what they put into their bodies. However, while sources like the internet have made lots of information available, there is also a lot of disinformation out there which can be hard to filter out."
She added, "So, it's not surprising there is confusion around how much we need of certain types of vitamins, or even where to get them from. This can be especially difficult for parents, who have to find the balance between what their children will actually eat, and then work out if it's good for them or not."
The study also revealed 25 per cent of parents worry about the levels of nutrition their children are getting, with 56 per cent turning to vitamin supplements to boost levels in their children.
Of those who don't buy supplements, 10 per cent are concerned they might contain too much sugar, and another 28 per cent say they are overwhelmed with the choice of supplements available and wouldn't know which one to buy.
Ms Kaur said, "All parents would agree it's vitally important to make sure your child grows up eating the right things. Whilst children should be able to get all the essential nutrients they need from diet alone, sometimes they can be fussy with their diet."
With the aim of the survey to spruik vitamin supplements for children, Ms Kaur advised parents to consider them so that childrens' nutrition could be supported.
While this option is readily available at a cost, education around healthy diets for children is another solution to the current knowledge gap.