Researchers from the National Institute for Public Health and the Environment (RIVM) in the Netherlands analysed actual concentrations of vitamin D in fortified foods and dietary supplements specifically intended for infants, and compared their findings to on-pack content declarations.
Writing in the journal Food Chemistry, they noted that while ‘a degree of variation’ between declared and analysed nutrient levels is expected, some of the actual vs on-pack variation found in the study falls outside of EU tolerance ranges – which allow fortified foods to be anywhere between−35% and +50% of declared levels and food supplements to be between -20% to +50% of on-label levels.
“It is (..) not always possible for food or supplements to contain the exact micronutrient level specified on the label, due to natural and processing variations, as well as changes during storage,” said the team, led by Janneke Verkaik-Kloosterman of RIVM. “But on the other hand, substantial deviation from what is labelled could mislead the consumer and should be prevented.”
“Compared to the declared values, the vitamin D content ranged from 50% to 153% for fortified foods and from 8% to 177% for supplements.”
Although in ‘most cases’these deviations are within the above EU limits both under- and over- estimation of vitamin D intake are possible, Verkaik-Kloosterman and colleaguessaid – adding thatserious vitamin D deficiencies in babies and infants can leads to rickets, while excessive vitamin D intake is linked to a risk of hypercalcaemia or hypercalciuria and kidney problems.
Pilot study
Vitamin D concentrations of 29 fortified foods and 15 food supplements were tested in the pilot study. Products tested included follow-on formula, baby porridge, and curd cheese dessert – all of which are specifically intended for infants.
For the fortified foods, the measured vitamin D content ranged between 50% and 153% of the declared value, whereas for dietary supplements this range was 8% to 177%.
Of the 44 products tested, Verkaik-Kloosterman revealed that three (3) fell outside of EU tolerance limits for variation in content levels.
In addition, to these EU tolerance limits, however, the team noted that fortified levels of vitamins should not deviate from any applicable (national) legislation limits. In this case, the Netherlands has set limits for follow-on formula, baby porridges with grains, and food supplements.
In general, the RIVM team found that instant follow-on formula and oil-based supplements had a measured vitamin D content similar to, or higher than, the labelled value. Meanwhile, ready-to-eat baby porridge was the only category in which all measured vitamin D concentrations were below the declared value (74% to 81% of labelled values).
A public health issue?
The current finding that actual vitamin D contents of fortified foods and supplements could be vastly different from their declared values might also be a concern from a public health perspective, said the authors – who noted that population-based assessments of dietary intake generally use ‘on label’ information for fortified foods and dietary supplements.
“These assessments and subsequent evaluations of too low or too high intakes may be invalid and inaccurate,” said the team.
Indeed, they noted that a previous scenario study in the Netherlands estimated that between 4% and 11% of infants aged 7–11 months would exceed the upper limit of 25 μg per day vitamin D intake (as set by EFSA) when it is assumed that they took a 10 μg supplement that is recommended by the Health Council of the Netherlands.
“The vitamin D concentration of fortified foods and dietary supplements of that scenario study were mainly obtained using label information,” wrote Verkaik-Kloosterman et al – noting that the number of children exceeding the EFSA upper limit (UL) would have been zero had children been receiving fortified foods and supplements with the lowest ‘actual’ levels found in the pilot study.
“On the other hand, the median intake would become 30–34 μg/d with at least 75% of the infants exceeding the UL if all of the highest proportional deviations were be applied,” they said.
Source: Food Chemistry
Volume 221, Pages 629–635, doi: 10.1016/j.foodchem.2016.11.128
“Vitamin D concentrations in fortified foods and dietary supplements intended for infants: Implications for vitamin D intake”
Authors: Janneke Verkaik-Kloosterman, et al