Abstract
Eating too much sodium increases the risk of developing high blood pressure which in turn may increase the risk of coronary heart disease and stroke. The Centre for Food Safety (CFS) and the Consumer Council (CC) have conducted a joint study on sodium content in savoury snacks. This study aims to assess sodium levels in savoury snacks available in the local market and enhance consumers' understanding on sodium and their awareness of the adverse health effects from excessive intake of sodium.
Background
2. The terms salt and sodium are often used synonymously, however, on a weight basis, salt comprises 40% sodium and 60% chloride (1g sodium chloride = 393.4mg of sodium).
3. Sodium is naturally present in plant and animal derived foods as well as drinking water. However, the major dietary source of sodium is from processed foods. Salt added to food during cooking and at the table also accounts for part of the sodium intake. Sodium may also present in the diet as food additives e.g. sodium nitrate (a preservative) and monosodium glutamate (MSG) (a flavour enhancer) in processed foods.
4. There is increasing concern over excessive intake of sodium internationally and locally. Eating too much sodium increases the risk of developing high blood pressure which in turn may increase the risk of coronary heart disease and stroke. Current evidence suggests that an intake of less than 1.7g of sodium per day is good for reducing blood pressure.
5. The World Health Organization and the Food and Agriculture Organization of the United Nations suggest the sodium and salt intakes should be less than 2g (or 5g of salt) a day.
6. In Hong Kong , the Food and Drugs (Composition and Labelling) (Amendment: Requirements for Nutrition Labelling and Nutrition Claim) Regulation 2008 was enacted by the Legislative Council on 28 May 2008 . Sodium is one of the nutrients specified for labelling i.e. the amount of sodium should be declared in the nutrition labelling of all prepackaged foods applicable to the Regulation from 1 July 2010 , after a grace period of about 2 years. Under the Amendment Regulation, "low sodium", "very low sodium" and "sodium free" claims are permitted if the prescribed conditions are met.
The study
7. This study covers various savoury snacks, including (i) savoury biscuits (e.g. saltine crackers, sandwich crackers, digestive biscuits, wafers and cheese crackers); (ii) crisps (e.g. potato chips, prawn crackers, rice crackers and corn nuts); (iii) nuts (e.g. peanuts, cashews, macadamias and almonds); (iv) meat and seafood products (e.g. fish balls, fish siu mai, squid floss, dried pork and beef jerky); (v) preserved fruits (e.g. dried orange peels, preserved lemons and preserved prunes); (vi) imitation shark fin soups and (vii) snack type seaweeds.
8. A total of 80 savoury snacks, including both prepackaged and non-prepackaged products, were purchased from local market. They were subject to laboratory analyses including sodium, total fat, saturated fat, trans fat, sugars and energy etc conducted by the Food Research Laboratory of the CFS.
9. Salient results of the study are summarised below:
- Nearly 60% (46 samples) of the samples were relatively high in sodium (according to the UK Food Standards Agency, a food is considered high in sodium if it contains more than 600mg sodium per 100g ). Only two samples met the definition of "low sodium" claim (not more than 120mg per 100g ) set out in the Amendment Regulation.
- Preserved fruits were relatively high in sodium, with the highest contained 13000mg sodium per 100g edible portion in a preserved prune sample .
- A peanut (200g) and a squid floss (102g) sample were found to contain 1100mg and 1900mg sodium per 100g respectively. Consumption of one pack already exceeds and approaches the daily recommended sodium intake limit respectively.
- Even though the sodium level in imitation shark fin soups is not very high, consumption of a type of imitation shark fin soup (320g; 560mg sodium per 100g) would intake 1792mg sodium, which accounts for about 90% of the daily recommended sodium intake limit.
- Sodium levels varied a lot among samples of some food categories. For example, in 100g sample, sodium levels in peanuts ranged from 180mg to 1100mg while in almonds they ranged from 60mg to 610mg.
10. In order to assess the sodium intake from various savoury snacks in the local population, the preliminary findings of the first Population-based Food Consumption Survey conducted by the CFS in 2005-2007 were taken into account. For preserved prune eaters, average and high consumer (95th percentile) consume about 9.63g (about 10 pieces) and 27.50g (about 27 pieces) preserved prune per day respectively. Assuming all preserved prune eaters consume only the preserved prunes included in this study, average and high consumer of preserved prune would take in about 973mg and 2778mg sodium from preserved prune a day, accounting for about 49% and 139% of the daily recommended intake limit respectively.
A summary of results is listed in the following table:
| Food products | No. of samples | Sodium range (mg/100g edible portion) |
|---|---|---|
| Savoury biscuits | 14 | 110-970 |
| Crisps | 17 | 340-1400 |
| Nuts | 15 | 60-1100 |
| Meat and seafood products | 19 |
530-1900 |
| Preserved fruits | 9 |
1100-13000 |
| Imitation shark fin soups | 3 |
370-560 |
| Snack type seaweeds | 3 |
1500-1700 |
| Total | 80 | 60-13000 |
Advice
11. The public is advised to maintain a balanced diet and make reference to the information in the nutrition label of prepackaged food to choose food that is lower in sodium (or salt), sugars and fat. The public is also advised to reduce the use of salt and high sodium/salt containing condiments e.g. soya sauce during food preparation.
12. The trade is advised to use less salt and sodium/salt containing ingredients during food preparation and to provide healthier food choices to consumers. Information including nutrient contents and claims on label should not be misleading.
March 2008
Risk Assessment Section
Centre for Food Safety
Food and Environmental Hygiene Department