Nutrient levels investigated
Nutrient levels investigated
"Variations in nutrient claims are not a food safety concern and are expected as the level of nutrient on the nutrition panel is based on an average," says New Zealand Food Safety Authority (NZFSA) Assistant Director (Joint Food Standards) Jenny Reid.
Her comments come in response to concerns raised after studies comparing actual nutrient levels with those claimed on the labels of a variety of products have found discrepancies.
"A lot of factors will influence the levels in any single serving of food, including analytical methods, storage conditions and the fact that manufacturers need to cater for possible degradation of the nutrient during its shelf life."
As part of its annual monitoring work, NZFSA commissions research from Environmental Science and Research on fortification overages in the food supply. This refers to the analytical levels of added nutrients in food versus the level stated in the Nutrition Information Panel (NIP).
Over the last three years a series of studies have been carried out looking at the nutrient levels of 260 samples from nine different food groups. The foods included fruit drinks, baby food, bread and cereal.
The nutrients tested were folic acid and iron (September 2005); Vitamin A, Vitamin D and calcium (June 2006), and Vitamin C, zinc and selenium (September 2007). The final survey included selenium in infant formula for which the Food Standards Code specifies minimum and maximum levels. For the other nutrients the Food Standards Code specifies maximum claimable (average) levels only.
The studies help NZFSA undertake a robust risk assessment of the consequences of nutrient additions to foods, both mandatory and voluntary, and will feed directly into the food standard setting process. They also provide guidance should there be issues of concern for further investigation.
Of the foods tested in the surveys almost 58 percent did not meet the label claims, with 15 percent containing less than the stated level of nutrient and 42 percent containing more than the label said.
Ms Reid says labels give you an average reading. "Rather than tell you exactly what nutrients you will get from eating a food on one occasion, the labels give you a picture of the nutrients you will get from routinely eating that particular product." She says labels are indicative and useful tools to provide guidance for people who want to compare different products. "They are not a blueprint of what someone is consuming on every occasion."
A lot of nutrients are not stable and levels may be affected by the production process, the shelf life of the product and the conditions the product is stored under. To compensate for any degrading that happens over time some manufacturers add more of particular nutrients.
International evidence suggests that actual levels can vary significantly by up to 320 percent of the claimed value and there is a potential public health and safety issue associated with over-consumption of some nutrients and interactions between nutrients if levels are too high. However, although a large number of the label claims on the foods sampled in the surveys did not meet the actual measured level, Ms Reid stresses that none of the results gave reason for concerns. "The permitted claimable levels of the various nutrients have huge inbuilt safety margins."
The reports on the fortification overages of the food supply can be found at: http://www.nzfsa.govt.nz/science/research-projects/index.htm
Background to the overage surveys:
As part of its annual monitoring work, NZFSA commissions research from ESR on fortification overages in the food supply. This refers to the analytical levels of added nutrients in food versus the level stated in the Nutrition Information panel (NIP).
Over the last three years a series of three research projects have been commissioned to determine levels of selected nutrients and comparisons made to levels claimed on labels and in particular in nutrition information panels (NIPs). The nutrients tested were folic acid and iron (September 2005); Vitamin A, Vitamin D and calcium (June 2006), and Vitamin C, zinc and selenium (September 2007). The final survey included selenium in infant formula for which the Food Standards Code specifies maximum and minimum levels. For the other nutrients the Food Standards Code specifies maximum (average) levels only.
This research allows NZFSA to keep abreast of voluntary use of fortification in the food supply and provide guidance should there be issues of concern for further investigation.
The results to date indicate that 58% of the products tested varied from the level stated on the label with the majority of these containing more than the label. These results need to be viewed in light of the limitations inherent in accurate reflection of the nutrients added to processed foods. These include:
Production and processing: • Adding small amounts of nutrients to large volumes of product and obtaining uniform distribution throughout • Need to cater for degradation of the nutrient during the shelf life of the product.
Sampling: • All analytical methods have associated uncertainty arising from sampling and the analytical methods used • While using the best scientific methodology available some of the analytical tests are extremely complicated and do not provide consistently reliable results.
Storage: • Storage conditions and the general food matrix will affect the final nutrient content.
The level of nutrient in the NIP is considered an "average" amount to take account of the various factors that influence the provision of nutrient information on a label. Nutrient content within a single packet of food can vary significantly hence an average value caters for the overall content of the packet rather than a single sample.
Nutrient information on labels can be most useful to provide comparison between similar groups of products and assist consumers in choosing between foods.
What NZFSA currently does in terms of food labelling compliance: NZFSA will continue to use the overage surveys as an indicator of areas for new work. NZFSA has recently repeated work on the levels of folic acid, particularly in light of the mandatory fortification of bread that will be introduced in September 2009 but we are waiting on the final results of these analyses.
Compliance surveys are conducted differently and include a detailed and robust sampling process to overcome the limitations of determining the nutrient levels – as outlined above.
What else NZFSA can do or intends to do: NZFSA is confident with the results to date that there are no issues of safety for the consumer. The permissions to add vitamins and minerals to food build in a significant safety factor and are considered extremely conservative allowing 15 – 50 % of the recommended daily intake (RDI).