Determination of sodium content of bread (Number 19/01)

The Food Standards Agency has recently carried out a survey to determine the levels of sodium in bread. This was in response to claims by industry that the levels of sodium in bread have been reduced since they were last analysed in 1998. Results show that the levels of sodium in the composite samples of all breads were lower than the levels obtained during the previous survey.

• Sixty samples of bread from five different categories (premium white sliced, standard white sliced, white bloomer bakery bread, wholemeal sliced and brown sliced) were purchased and analysed to determine the levels of sodium present. Breads were analysed both individually and as composite samples of each type.
• On comparison with the data obtained in 1998, results from this most recent survey show that:
  • the levels of sodium in the composite samples of pre-packed sliced breads (white, brown and wholemeal) have been reduced since breads were last analysed;
  • the reduction in the level of sodium in standard white sliced breads appears to be greater than the reduction for the premium white breads;
  • the reduction in the sodium content of standard white sliced bread is larger than the reduction in the brown/wholemeal breads, but present levels of sodium in all these sliced, pre-packed breads are similar.
  • results for the bakery breads show a smaller reduction in sodium levels than for the other breads tested.
  • Whilst we have individual retailers results for this survey, it is not possible to provide comparisons for individual retailers breads as these were not tested in 1998.

The last major survey on the nutritional composition of breads was carried out in 1998,¹ as part of the rolling programme of nutrient analysis that the Agency undertakes to ensure that the Government has reliable, up-to-date information on the nutritional value of foods. Since that survey was conducted, industry has reported a reduction in the levels of sodium in some breads. As a result, there was a need to update the information held by the Agency.

Salt intakes are currently around 9 grams per person per day, which is considerably higher than the recommended intake of 6 grams per person per day.² A habitually high intake of sodium has been linked to a higher than average blood pressure, which may lead to an increased risk of suffering heart disease or a stroke.

In 2000, bread contributed around 22 per cent to the overall intake of sodium from the household diet,.³ indicating that it is one of the main sources of sodium in the diet. Table salt, cereal products other than bread, meat products including bacon and ham, and milk are also major contributors to sodium intakes.⁴ Not all of these foods are considered to have a high sodium content; it is because they are eaten in large amounts that their overall contribution to sodium intake is relatively high.

The results of this survey will be incorporated into the Agency's nutrient databanks for the National Diet and Nutrition Survey programme, and the Expenditure and Food Survey, together with future publications in the series McCance and Widdowson's The Composition of Foods.

Sixty samples of bread (white, wholemeal and brown) were purchased in the south east of England during summer 2001. As the purpose of the project was to update information obtained during the previous analyses of bread, the sampling protocol was designed to mirror, as far as possible, that used for the 1998 survey. Inevitably there were some breads that had been discontinued in the intervening period. These were replaced with an alternative, produced by the same manufacturer or retailer, where possible. If this was not possible, the breads were excluded.

The purchased breads were bulked together for analysis to form the same five composite samples as those analysed in 1998. These composite samples were:

• White bread, premium loaves, sliced, pre-packed, large
• White bread, standard loaves, sliced, pre-packed, large
• White bread, crusty bloomer, unsliced, freshly baked, large
• Wholemeal bread, sliced, pre-packed, large
• Brown bread, sliced, pre-packed, large

These five categories of breads cover approximately 89 per cent of the bread market⁵ hence their inclusion in this survey.

This allowed comparisons to be made with the figures collected during the previous survey. Each bread that contributed to the composite samples was also analysed individually. A full list of the individual samples analysed is included at Table 1. The absence of a particular brand means only that the brand has not been included in the survey. No further meaning should be read into its absence from the report.

The individual and composite samples were analysed by the Laboratory of the Government Chemist for sodium only. An in-house UKAS accredited method was used for the analysis. Samples were dry ashed for 16 hours at 500oC. The resulting ash was dissolved in dilute hydrochloric acid and sodium was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Details of the quality control measures employed are given in the analytical report.

The results of the analyses of the composite samples can be found in Table 2. The category number for each composite sample corresponds to that used in the previous survey. On comparison with the data obtained in 1998, results from this most recent survey suggest that:

• On average, the sodium level in bread has fallen by 13 per cent since 1998.
• The levels of sodium in the composite samples of pre-packed sliced breads (white, brown and wholemeal) have been reduced since breads were last analysed.
• The reduction in the level of sodium in standard white sliced breads appears to be greater than the reduction for the premium white breads.
• The reduction in the sodium content of standard white sliced bread is larger than the reduction in the brown/wholemeal breads, but present levels of sodium in all these sliced, pre-packed breads are similar.

Results are not so clear for the bakery bread (category number 6 - White bread, crusty bloomer, unsliced, freshly baked, large). The composite sample of this bread appears to suggest that there is little difference in the sodium level of white bakery bread from when this was last analysed in 1998.

This same category also included the only independent bakery breads analysed for the survey. The levels of sodium present in these breads appear to be similar to the levels obtained for the same type of loaf baked in store by the large multiples.

Whilst we have results for individual retailers breads from this survey, it is not possible to provide comparisons over time as these were not tested in 1998.

When compared to the level of sodium given on the packaging, the results obtained for the majority of breads were generally within the limits of analytical variation (+/- 20 per cent). However, the results obtained for 5 breads were outside this limit, with levels that were considerably above the amount declared on the label. The relevant manufacturers were contacted and asked to comment on these findings. The comments received can be found at Annex 1.

The results for the individual breads can be found at Table 3. The full analytical report is available in hard copy through the FSA Library and Information Service at Aviation House.

The results of this survey show that the levels of sodium in bread have fallen by an average of 13 per cent since these were last analysed in 1998. Although the amount of the decline varies between the different categories of breads tested, the average reduction is in line with the figure reported by industry.

1. Ministry of Agriculture, Fisheries and Food. Nutrient Analysis of Bread and Morning Goods. Food Surveillance Information Sheet no 194, 2000.
2. Department of Health. Nutritional Aspects of Cardiovascular Disease Report on Health and Social Subjects no 46. London: HMSO, 1994.
3. DEFRA. National Food Survey 2000. London: The Stationery Office, 2001.
4. MAFF. Manual of Nutrition, Tenth Edition. London: HMSO, 1995.
5. Mintel. Bread, February 2001. London: Mintel International Group Ltd, 2001.

The report of this survey (entitled The Determination of the Sodium Content of Bread) is held in the Dr Elsie Widdowson Library and Information Service at the Food Standards Agency headquarters in London. If you would like to consult or receive a copy, please contact:

Dr Elsie Widdowson Library and Information Service
Food Standards Agency
Ground Floor, Aviation House
125 Kingsway
London WC2B 6NH
Tel: +44 (0) 20 7276 8181/8182
Fax: +44 (0) 20 7276 8069
E-mail: library&info@foodstandards.gsi.gov.uk

A small charge for Photocopying will be made.

Other enquiries should be addressed to:

Ms Alette Weaver
Food Standards Agency
Nutrition Division
Room 801C, Aviation House
125 Kingsway
London WC2B 6NH
Tel: +44 (0) 20 7276 8905
Fax: +44 (0) 20 7276 8906
Email: alette.weaver@foodstandards.gsi.gov.uk