Response to: Rikkers et al. Trends in sugar supply and consumption in Australia: is there an Australian Paradox?
Tom McNeill, Green Pool Commodity Specialists
28 October 2013
Response to:
Rikkers et al. Trends in sugar supply and consumption in Australia: is there an Australian Paradox? BMC Public health 2013, 13:668 doi: 10.1186/1471-2458-13-668
By: Tom McNeill, Email: tom@greenpoolcommodities.com, Address: Green Pool Commodity Specialists, Kangaroo Point, Brisbane, Qld 4169, Australia
Rikkers et al. [1] in the Journal BMC Public Health, revisit the question of sugar consumption in Australia. Their premise is that previous studies on total use of refined sugar in food consumed in Australia had neglected to measure the sugar content of imported foods. The two research analyses referred to by Rikkers et al. were that of Barclay and Brand-Miller [2] and Green Pool Commodity Specialists [3]. Both of these papers had pointed to declining sugar (defined as sucrose or refined sugar) consumption per capita over at least 20 years in Australia. Both of these studies accounted for the import of sugar-containing products.
Green Pool¿s analysis sets out, in substantial detail, the methodology under which some 173 categories of imported sugar-containing foods and beverages and 120 categories of exported sugar-containing foods and beverages were accounted for in terms of sugar content. A full balance of sugar contained in imports versus sugar contained in exports was detailed. Despite this, Rikkers et al. state a number of times that prior studies do not account for the sugar content of imports. The authors appear to ignore Australian Bureau of Statistics (ABS) apparent consumption data to 1998/99 and the continuation of the data series to 2011 by Green Pool using the same methodology.
Rikkers et al. use a wide range of data for their study. Yet the utilisation of less data sources may have helped with continuity and completeness of data. Data integrity would also have been helped by using less "derived" or estimated data and more primary data. In the pursuit of the quantity of sugar used in manufacturing foods in the Australian market, Rikkers et al. failed to include aggregated quantity sales data from sugar refiners and manufacturers of food grade sugar in Australia. The authors instead use "estimates of production contained in the ABS Australian Supply Use tables from the Australian National Accounts Input-output Electronic Publications 1994-2008 as the best available measures of local production of a range of foods". This data introduces a range of potential errors since any estimates of sugar use must be derived from estimates of sugar contents across thousands of products and product variations.
Additionally, such data is supplemented by total aggregate value data, introducing further sources of error such as price inflation and category aggregation. Rikkers et al. deflate price data to derive deflated price data over time which is then divided by value per product to derive total quantity of product sold. This is then multiplied by a sugar content factor to derive sugar quantity. This convoluted methodology introduces estimates at several levels, leaving final data in which little confidence can be held.
Perhaps Rikkers et al.'s biggest source of error is the inclusion of incorrect products in the category of "moderate to high sugar content", in violation of their study inclusion criteria. Fruit juices and fruit drinks have been added to the analysis by the authors without consideration of their actual sugar content, or the very definition of these products which must be adhered to by food manufacturers under the control of Food Standards Australia and New Zealand (FSANZ). Standard 2.6.1 of the Food Standards Code states fruit juice should have no more than 4g/100g of sugars added [4]. Therefore to include fruit juice in this analysis while stating the study inclusion criteria is 5 to 15g sucrose per 100g for medium and [greater than or equal to] 15g sucrose per 100g for high sugar category is clearly incorrect. In fact, the Australian fruit juice industry operates an additional standard whereby fruit juice is defined as all unsweetened fruit juice, with >99% juice. This definition, currently adhered to by Australian manufacturers, only allows for 1% nutrients (which may have been lost during preparation) to be added to the juice. It is not clear that any fruit juices produced in Australia meet the authors' inclusion criteria.
Fruit drinks are defined by FSANZ Standard 2.6.2 with no specifications of sugar content except that they may contain sugars [5]. According to FSANZ nutrient data for foods available in Australia (NUTTAB 2010), not all fruit drinks have more than the 5g sucrose per 100g criteria as specified by the authors [6]. For example the fruit drink 25% Apple Juice contains 2.1g sucrose per 100 ml [6].
It is clear that by adding fruit juices as an apparently high added sugar category for domestic manufacturing and imports, the authors substantially overstate overall sugar content estimates. This may also be true for fruit drinks, as clearly their sugar content cannot just be assumed.
Rikkers et al. set out with the aim of investigating whether estimates of refined sugar and added sugars including the content of imported products is increasing or decreasing. The authors' intention was to bring new research into the debate. However, by using secondary and tertiary sources of data, and the inclusion of incorrect categories described as high added sugar content, the authors introduce errors too large to be glossed over. Additionally, the rejection of simpler methodologies and the authors' admission that much of the key data has been derived or estimated brings any conclusions from the study into question.
References
1. Rikkers et al. Trends in sugar supply and consumption in Australia: is there an Australian Paradox? BMC Public health 2013, 13:668 doi: 10.1186/1471-2458-13-668
2. Barclay and Brand-Miller .The Australian Paradox: A Substantial Decline in Sugars Intake over the Same Timeframe that Overweight and Obesity Have Increased. Nutrients 2011, 3, 491-504; doi:10.3390/nu3040491
3. Sugar Consumption in Australia. A statistical update. 4 October 2012. Green Pool Commodity Specialists, Brisbane, Australia
4. Australia New Zealand Food Standards Code - Standard 2.6.1- Fruit Juice and Vegetable Juice. F2009C00908 Australian Government ComLaw http://www.comlaw.gov.au/Details/F2009C00908
5. Australia New Zealand Food Standards Code - Standard 2.6.2- Non Alcoholic Beverages and Brewed Soft Drinks. F2013C00145 Australian Government ComLaw http://www.comlaw.gov.au/Details/F2013C00145
6. Food Standards Australia New Zealand. Nutrient tables for use in Australia (NUTTAB) 2010. http://tinyurl.com/nms7k9b
Response to: Rikkers et al. Trends in sugar supply and consumption in Australia: is there an Australian Paradox?
28 October 2013
Response to:
Rikkers et al. Trends in sugar supply and consumption in Australia: is there an Australian Paradox? BMC Public health 2013, 13:668 doi: 10.1186/1471-2458-13-668
By: Tom McNeill, Email: tom@greenpoolcommodities.com, Address: Green Pool Commodity Specialists, Kangaroo Point, Brisbane, Qld 4169, Australia
Rikkers et al. [1] in the Journal BMC Public Health, revisit the question of sugar consumption in Australia. Their premise is that previous studies on total use of refined sugar in food consumed in Australia had neglected to measure the sugar content of imported foods. The two research analyses referred to by Rikkers et al. were that of Barclay and Brand-Miller [2] and Green Pool Commodity Specialists [3]. Both of these papers had pointed to declining sugar (defined as sucrose or refined sugar) consumption per capita over at least 20 years in Australia. Both of these studies accounted for the import of sugar-containing products.
Green Pool¿s analysis sets out, in substantial detail, the methodology under which some 173 categories of imported sugar-containing foods and beverages and 120 categories of exported sugar-containing foods and beverages were accounted for in terms of sugar content. A full balance of sugar contained in imports versus sugar contained in exports was detailed. Despite this, Rikkers et al. state a number of times that prior studies do not account for the sugar content of imports. The authors appear to ignore Australian Bureau of Statistics (ABS) apparent consumption data to 1998/99 and the continuation of the data series to 2011 by Green Pool using the same methodology.
Rikkers et al. use a wide range of data for their study. Yet the utilisation of less data sources may have helped with continuity and completeness of data. Data integrity would also have been helped by using less "derived" or estimated data and more primary data. In the pursuit of the quantity of sugar used in manufacturing foods in the Australian market, Rikkers et al. failed to include aggregated quantity sales data from sugar refiners and manufacturers of food grade sugar in Australia. The authors instead use "estimates of production contained in the ABS Australian Supply Use tables from the Australian National Accounts Input-output Electronic Publications 1994-2008 as the best available measures of local production of a range of foods". This data introduces a range of potential errors since any estimates of sugar use must be derived from estimates of sugar contents across thousands of products and product variations.
Additionally, such data is supplemented by total aggregate value data, introducing further sources of error such as price inflation and category aggregation. Rikkers et al. deflate price data to derive deflated price data over time which is then divided by value per product to derive total quantity of product sold. This is then multiplied by a sugar content factor to derive sugar quantity. This convoluted methodology introduces estimates at several levels, leaving final data in which little confidence can be held.
Perhaps Rikkers et al.'s biggest source of error is the inclusion of incorrect products in the category of "moderate to high sugar content", in violation of their study inclusion criteria. Fruit juices and fruit drinks have been added to the analysis by the authors without consideration of their actual sugar content, or the very definition of these products which must be adhered to by food manufacturers under the control of Food Standards Australia and New Zealand (FSANZ). Standard 2.6.1 of the Food Standards Code states fruit juice should have no more than 4g/100g of sugars added [4]. Therefore to include fruit juice in this analysis while stating the study inclusion criteria is 5 to 15g sucrose per 100g for medium and [greater than or equal to] 15g sucrose per 100g for high sugar category is clearly incorrect. In fact, the Australian fruit juice industry operates an additional standard whereby fruit juice is defined as all unsweetened fruit juice, with >99% juice. This definition, currently adhered to by Australian manufacturers, only allows for 1% nutrients (which may have been lost during preparation) to be added to the juice. It is not clear that any fruit juices produced in Australia meet the authors' inclusion criteria.
Fruit drinks are defined by FSANZ Standard 2.6.2 with no specifications of sugar content except that they may contain sugars [5]. According to FSANZ nutrient data for foods available in Australia (NUTTAB 2010), not all fruit drinks have more than the 5g sucrose per 100g criteria as specified by the authors [6]. For example the fruit drink 25% Apple Juice contains 2.1g sucrose per 100 ml [6].
It is clear that by adding fruit juices as an apparently high added sugar category for domestic manufacturing and imports, the authors substantially overstate overall sugar content estimates. This may also be true for fruit drinks, as clearly their sugar content cannot just be assumed.
Rikkers et al. set out with the aim of investigating whether estimates of refined sugar and added sugars including the content of imported products is increasing or decreasing. The authors' intention was to bring new research into the debate. However, by using secondary and tertiary sources of data, and the inclusion of incorrect categories described as high added sugar content, the authors introduce errors too large to be glossed over. Additionally, the rejection of simpler methodologies and the authors' admission that much of the key data has been derived or estimated brings any conclusions from the study into question.
References
1. Rikkers et al. Trends in sugar supply and consumption in Australia: is there an Australian Paradox? BMC Public health 2013, 13:668 doi: 10.1186/1471-2458-13-668
2. Barclay and Brand-Miller .The Australian Paradox: A Substantial Decline in Sugars Intake over the Same Timeframe that Overweight and Obesity Have Increased. Nutrients 2011, 3, 491-504; doi:10.3390/nu3040491
3. Sugar Consumption in Australia. A statistical update. 4 October 2012. Green Pool Commodity Specialists, Brisbane, Australia
4. Australia New Zealand Food Standards Code - Standard 2.6.1- Fruit Juice and Vegetable Juice. F2009C00908 Australian Government ComLaw http://www.comlaw.gov.au/Details/F2009C00908
5. Australia New Zealand Food Standards Code - Standard 2.6.2- Non Alcoholic Beverages and Brewed Soft Drinks. F2013C00145 Australian Government ComLaw http://www.comlaw.gov.au/Details/F2013C00145
6. Food Standards Australia New Zealand. Nutrient tables for use in Australia (NUTTAB) 2010. http://tinyurl.com/nms7k9b
Competing interests
Director of Green Pool Commodity Specialists