SAIN-LIM

Score of Nutritional Adequacy of Individual Foods and Score of Nutrients to be Limited (The SAIN-LIM System)

Whilst nutrition enhancement focuses on the links between the substance of food and physiological function or the development of diseases, the overall quality of the food must also be considered. While the previous food indicators in our Diet dq Tracker focus on the diversity of food groups, the SAIN-LIM system focuses on the overall nutrition quality of the food. This sometimes can prove to be difficult as one must assess the nutritional quality of each foodstuff consumed by an individual.

The SAIN-LIM system is based on the idea that nutrition is above all a matter of balance and diversity in one’s diet as complementary foods are combined in a way that allows all of one’s nutritional needs to be met.

To grasp the concept of the SAIN-LIM system, one must first understand the following definitions on which the SAIN-LIM system is built upon:

• Nutrient profiling is the classification of foods on the basis of their nutritional composition
• The nutrient profile of a food item is an overall expression of its nutritional quality
• Classification is the grouping of foods following the application of a nutrient profiling scheme
• Categorisation is the grouping of foods according to predefined criteria that may be regulatory, nutritional or customary

Defining nutrient profiles is closely linked to public health objectives which can vary from one country to another and span issues like obesity prevention, reduction in cardiovascular diseases or the diseases caused by ageing, to name a few. Thus, the NP scheme enables the SAIN-LIM system to be adapted in line with these variations through the choices of nutrients consumed and their relative weights which are considered when determining a food’s nutrient profile.

There are three types of models for nutrient profiling systems:

• Category-based system
• Across-the-board system
• Combined systems

The SAIN-LIM system uses the across-the-board profiling model as this system sets NPs for food in general overcoming the problem of defining and managing food groups.This is a major strength of the across-the-board profiling system. However, when using this model, a complex system must be set up that takes into account the diverse nutritional compositions of products given that the same criteria are used for defining NPs of foods that can be intrinsically different. A major drawback to the across-the-board profiling is that it can lead to the exclusion of certain foods almost exclusively containing a single macronutrient (such as oil) because of a high content of disqualifying nutrients and yet, these foods may contribute essential nutrient intake. Subsequently, profiles should take into account the variability of dietary habits and traditions allowing for product innovation and the consideration of how important a role a food might play in the context of one’s overall diet.

The SAIN-LIM nutrient system has been tested on over 600 food items and based on criteria set:

• More than 33% of the food items were classified as eligible to bear health claims particularly,
  • 80% of fruit and vegetables
  • Unrefined starchy foods
  • 50% of products in the meat/eggs/fish category
  • Low-sugar and low-fat dairy products
  • Milk
• More than 25% of food items were classified as not eligible for bearing a nutrition or health claim

The SAIN and LIM scores for any given food reflect the nutrient density and energy of that foodstuff respectively. The SAIN or nutrient density score is the mean of percentages of recommended dietary intakes for a defined number of qualifying nutrients. On the contrary, the LIM or limited nutrient score is the mean of percentages of maximum recommended intakes for a defined number of disqualifying nutrients. The SAIN-LIM system is identical for all foods and combines two (2) complementary, non-compensatory scores. The SAIN threshold reference value is considered the minimum value for qualifying nutrients to reach, while the LIM reference value is an upper limit that should not be exceeded.

It is important to note that the SAIN gives the qualifying nutrients per 100kcal while the LIM provides the disqualifying nutrients per 100g of food. The choice to use this combined calculation is in line with current recommendations to promote foods with low energy density (ED) and high nutrient density (ND). In addition, the SAIN and LIM formulae are continuous and linear and imply the definition of reference values and avoid the need for a weighting system between the variables used making the calculation of scores easy.

Initial studies conducted on the SAIN (nutrient density) the LIM (limited nutrient) scores were initially developed to examine the relationship between the cost of food and its nutritional quality and revealed a positive correlation between the two. In addition, further studies applied the SAIN-LIM system to previously defined categories and revealed that in general:

• The ‘fruit and vegetables’ category have a high SAIN and low LIM
• The ‘meat/egg/fish’ category have a high SAIN and moderate LIM
• The ‘added fats’ category and products such as desserts and snacks have low SAIN and high LIM
• ‘Dairy products’ and ‘ready meals’ have intermediate SAIN and LIM scores

These studies found that most commonly, a high SAIN is generally correlated with a low LIM. Furthermore, the SAIN and LIM indicators are found to be globally consistent with expert opinions with respect to the comparative nutritional quality of food categories.

To understand and graph SAIN-LIM scores, nutrient scores are compared to reference points in order to identify scores allowing, or otherwise, access to health claims. For the SAIN reference, a daily intake of 2000kcal was established which is equivalent to 5% for 100kcal of food. For the LIM however, a daily maximal intake of 1330g was chosen which is equivalent to 7.5% for 100g of food. Thus, a SAIN value greater than or equal to five indicates a good nutrient density while a LIM value less than 7.5 indicates a low content of limited nutrients. These reference points correspond to the references accepted in the context of European discussion on nutrition labelling and is consistent with the mean daily quantities of food consumed by a non-underreporting French adult.

When using the SAIN-LIM system, the recommended values (RVs) for the five basic qualifying nutrients and maximal recommended values (MRVs) for the three main disqualifying ingredients are provided in the table. There are of course optional nutrients like vitamin D that once can add to the system depending on the specifics of the intervention as well as the foods available in the community.

Based on the SAIN-LIM system, foods can be classified into 4 classes. Class 1 foods primarily include foods with the most favourable nutrient profile as they are high in nutrient density and have a low content of limited nutrients whereas, class 4 includes foods with the least favourable nutrient profile as they are low in nutrient density and have a high content of limited nutrients. Furthermore, foods found within class 2 and 3 are considered neutral foods as their nutritional quality is intermediate. When using the SAIN-LIM system, a negative relationship between nutrient and energy densities is consistently found as well as a positive relationship between LIM and energy density again showing that high SAIN is generally correlated with a low LIM.

In the SAIN-LIM system all health claims are not considered separately other than health claims referring to the reduction of disease risk and claims referring to children’s development and health. Thus, based on the graph, foods in quadrant 1 (fruits and vegetables for example) and quadrant 2 (refined cereals for example) have access to health claims.