Protocol used to select constituents to be analysed

The aim of this project is to draw up a nutritional composition table for aquatic products. By definition, such a table must provide the fullest possible nutritional profile for each of the stated foodstuffs. But more precisely, which nutrients should feature in this table?

Given the cost of nutritional analyses, it is essential that analyses be limited to nutrients which are of relevance in the aquatic products and/or which are of particular nutritional interest.

The relevance of nutrients has been defined on the basis of four main criteria:

1. Absence or presence of certain nutrients in the aquatic products, according to the data available
2. Importance of various nutrients for public health
3. Current regulation in the area of labelling and nutritional claims at the date of undertaking the project
4. Technical constraints

The bank of data at AFSSA’s (the French Food Safety Agency) Centre of Information on Food Quality (Centre d’Information sur la Qualité des Aliments) centralises a range of data on the composition of foods taken from scientific literature (articles, foreign composition tables), projects or the labels of commercialised products. While there were many gaps before this project is undertaken (the CIQUAL table has since been updated), the advantage of this table was that it provided orders of magnitude for the levels of various nutrients in a wide range of aquatic products. 

This table enabled us to identify:

• the nutrients which are barely present in or even absent from the edible part of the aquatic products (such as vitamin C, vitamin B9, copper, etc.);
• and conversely, those that are present in significant quantities in terms of Recommended Daily Allowances - or RDA - (defined by the regulations for a limited number of nutrients) or by default, in terms of Recommended Dietary Allowances[1] - or ANC - (defined by a group of French experts for a greater number of nutrients). We might mention for example vitamin D in fatty fish, vitamin B6, vitamin B12, phosphorus, iron, iodine, etc.

Surveys of food consumption such as the INCA survey[2] allow us to determine average nutrient intakes in the French population as a whole and in particular sections of the population. These intakes can be compared to the ANC recommendations, enabling us to identify any deficiencies, defects or excesses in a nutrient in a group of individuals. Recommendations in the field of public health can then draw on the conclusions to these comparisons. It seems appropriate to position aquatic products in relation to these recommendations.

For example, the Plan National Nutrition Santé (National Nutrition and Health Programme) (currently in its second incarnation) takes stock of nine priority public health objectives. These objectives include increasing calcium consumption in order to achieve a 25% cut in the number of people with calcium intakes below the ANC, while also reducing the prevalence of vitamin D deficiencies by a quarter. Aquatic products seem to have valuable vitamin D levels according to preliminary data; actual analysis of vitamin D to obtain reliable data is therefore a priority in our project. Other nutrients of particular interest in the area of public health are for example Omega 3 fatty acids, vitamin E, magnesium, iron, selenium, iodine, etc. Chloride was analysed to estimate levels of salt, the content of which in our diet is to be reduced.

When the project was launched, one of the main objectives was to help professionals in the sector to label their products to comply with regulations. Regulations in force at this time described two groups of nutrients for nutritional labelling: group one included energy values, proteins, fats and carbohydrates. Group two included group one nutrients, in addition to sugars, saturates, dietary fibre and sodium. If we chose, for example, to label a product’s sodium content, we would also need to label the levels of all the other group two components, in addition to group one components. Furthermore, if we wanted to label a mineral or a vitamin, it is compulsory to label at least the levels of group one constituents.

This notion of a group in nutritional labelling makes it necessary to analyse protein and total fat. For carbohydrate, fibre and sugar, analysis is irrelevant because aquatic products only contain trace levels.

These different constraints make it essential, in some cases, that we analyse nutrients which do not meet the three preceding criteria:

• The method used to analyse fatty acids (gas chromatography) does not just quantify fatty acids of major public health interest (omega 3, saturates, etc.). This is why the data presented as part of this project lists many other fatty acids.
• Product moisture content was measured because it makes it possible to describe them clearly, especially when they are transformed (how cooked they are, how much sauce they contain, etc.) and to identify any changes occurring during storage.
• Ash content is a parameter which enables us to monitor data coherence: total mineral contents must always be lower or equal to ash content.

1. Apports nutritionnels conseillés pour la population Française (Recommended dietary alllowances for the French population), coor. A. Martin, 2001, 3rd edition, Tec & Doc Lavoisier, 605pp

2. Enquête INCA individuelle et nationale sur les consommations alimentaires (Individual National Survey of Food Consumption) , coor. J.-L. Volatier, 2000, Tec & Doc Lavoisier 158pp