We all know we should be eating vitamins and minerals but not many know how much. Is there a gap between nutrient reference values vs nutrient intake in Australia?
What are nutrient reference values?
Nutrient reference values (NRV) are the recommended levels of intake of different nutrients, based on scientific evidence about food intake and health.
The NRVs for Australia and New Zealand are expressed as a recommended daily intake (RDI) of each nutrient, which is the average amount of the nutrient that is required for the majority of healthy individuals. For some nutrients where the RDI could not be determined, the recommendation is based on the adequate intake (AI) which is the average amount observed in healthy people. Some nutrients have upper levels of intake (UL), the limit beyond which they can be toxic (1).
NRVs are reported for macronutrients and micronutrients for each gender, age group and life stage (pregnancy and lactation).
Nutrient reference values vs nutrient intake in Australia
To reflect the gap between NRVs and nutrient intake, I’ve compared the NRVs to the intake based on the Australian Health Survey from 2011-2012 (2). I have included only the nutrients that have NRVs and were measured in the survey except for most macronutrients and water. This is because energy, protein and water requirements are better calculated individually.
Regarding specific NRVs, the comparison was made using the RDI when available. UL will be discussed in a later article. Similarly, comparisons for pregnant and lactating females will be addressed in a future article.
Only boys up to 8 years old and girls up to 3 years old met the RDI for dietary fibre. This is not surprising if we consider that in Australia the fruit and vegetable intake is low and we eat too many discretionary choices (a.k.a. junk food).
Vitamin A retinol equivalents
For vitamin A equivalents, there was a strong gender effect. Males 14-50 years old did not meet the RDI, and only females 14-18 did not meet the RDI. This correlates with the fact that females tend to eat more fruit and vegetables than men.
No one had issues meeting their RDI of thiamin (vitamin B1) thanks to the mandatory fortification of bread flour in Australia.
As with thiamin, all Australians met their requirements for riboflavin, which is widely available in milk, dairy products, and fortified breads and cereals.
Niacin is another nutrient that people have no problem meeting as it’s available in many foods.
Folate is available in vegetables, legumes, cereals and cereal-based dishes (the last two due to mandatory fortification with folic acid), therefore most people had no problem meeting the RDI. One exception that is not reflected in the graphs below is women looking to get pregnant and in the first trimester of pregnancy. In these cases, requirements increase due to the importance of folate in the development of the fetus and some females did not meet this higher RDI. Again, pregnancy and lactation requirements will be addressed in a future article.
Both males and females 51 years old and over did not meet their RDI for vitamin B6.
Similarly to vitamin B6, on average it looks like nobody had problems meeting the RDI for vitamin B12. However, vegans and strict vegetarians who don’t take a supplement are likely to be deficient on vitamin B12.
Vitamin C is another nutrient not at risk of deficiency for the general population.
Only older male adults 71 years and over did not meet the RDI for vitamin E. Vitamin E occurs naturally in some foods such as oils and fats, and added to others as anti-oxidant.
Only boys 2-8 years and girls 2-3 years old met the RDI for calcium thanks to their consumption of milk. This is concerning considering that calcium is an important nutrient in all stages of life.
Only females 51 years old and older did not meet the RDI for iodine. This is likely linked to sodium intake, which declines in this population group. Iodine is naturally present in some marine foods and is voluntarily added to salt.
Both the requirements and intake of iron differ between genders. While only boys 2-8 years old did not meet the RDI, girls 2-8 and 14-18 years old and women 19-50 years old did not meet the RDI. The target is higher for women in child bearing age to make up for the loses during menstruation. At the same time, women tend to eat less red meat, which is an important source of iron.
Only children 2-13 years old met the RDI for magnesium. This nutrient is present in many whole foods and not in refined foods.
Most people, except for girls 9-13 years, old met the RDI for phosphorus. Like magnesium, phosphorus is present in many whole foods but also present as additive in processed foods.
Only boys 2-3 years old met the RDI for potassium. Boys 4-8 years old and girls 2-3 years old were close. Potassium is present in many whole foods, which we are not eating enough of.
No population group had problems meeting the selenium RDI. Selenium is present in seafood, poultry and eggs. It is also present in cereal products but the amount depends on the soil where the cereals were grown. Brazil nuts are also a good source of selenium.
Sodium NRVs are expressed as AI ranges. The graphs below reflect the upper end of those ranges for children and adolescents. For adults, the graphs reflect the suggested dietary target (SDT), which aims to prevent chronic disease. Considering that most of the sodium in our diets comes from processed and restaurant foods, it is not a surprise that all males exceeded the AI/SDT and for females, only those 51 and over were below the SDT but over AI.
Zinc is another nutrient that has a gender-based NRV. Males have a higher requirement due to loses in semen, which explains why males 14 and over did not meet the RDI.
Summary and recommendations
On average, most Australians are meeting the NRV for many nutrients. Nutrients of concern are calcium, iron, zinc and vitamin B12 for some population groups, and sodium and potassium for most people. But even if we meet all requirements, where are we getting our nutrients for? As seen in a recent article on ultra-processed foods, health issues can arise when we consume too many processed foods, regardless of their nutrient content. Food for thought.
- National Health and Medical Research Council, Australian Government Department of Health and Ageing, New Zealand Ministry of Health. Nutrient Reference Values for Australia and New Zealand. Canberra: National Health and Medical Research Council; 2006
- Australian Bureau of Statistics 2016, Australian Health Survey: Nutrition First Results – Foods and Nutrients, 2011–12 — Australia, ‘TABLE 1.1 Mean daily energy and nutrient intake’, data cube: Excel spreadsheet, cat. no. 4364.0.55.007, viewed 15 September 2020, https://www.abs.gov.au/ausstats/subscriber.nsf/log?openagent&Table%201%20Mean%20daily%20energy%20and%20nutrient%20intake.xls&4364.0.55.007&Data%20Cubes&C53378E733B57D2CCA257CD200146C93&0&2011-12&09.05.2014&Latest