Food and Nutrient Tables: Are They a Definitive Guide to Healthy Eating?

The difficulties of constructing food composition tables and nutrient databases lie mainly on the fact that choosing foods would commensurate on various criteria. The quality of food composition data is greatly influenced by the control of variation in food composition, the accuracy in the description of nutrients, the methods of analysis and the mode of data expression (Leclercq et al., 2002).

Fact is that the most important macronutrients and minerals are well covered in European food composition databases, but fractions of nutrients (such as fractions of carbohydrates) and vitamins are stated less extensively in some countries. Other nutrients are generally present but the data may be lacking for some foods or be available only for raw foods. Also, tables of food composition never include all processed foods available on a national market.

The true range of food items available for consumption is almost impossible to document due to the continuous introduction of new products and variation in recipes. Another issue is that there are differences of analytical data between tables are both actual (due to variability in the composition) and artifactual (Leclercq et al., 2002). Foods, as biological materials, exhibit natural variations in the amounts of nutrients contained. Variability is higher for some nutrients, especially micronutrients. For example, processed foods can be tricky to recommend because there are variations in the composition of ingredients and changes in formulation and production over time. Another crucial point for the comparability of food composition data between countries is that of the definition of foods. The usage of free language can lead to misunderstanding because the same food product could be named in different ways and, on the other side, different products could be indicated by the same name. For example, the name of fishes varies from region to region.

Lastly, the difficulty in constructing food composition databases is showcased in the differences in the description of nutrients. The current terms fat, protein and carbohydrates in food tables still refer, in most instances, to chemically inconsistent, so called “crude” fractions in foods, which do not behave uniformly in digestion and human nutrition and are unreliable for energy calculations. In the case of carbohydrates and fibre, from a nutritional point of view, there would be a need to distinguish between glucose, fructose, galactose, sucrose, lactose, maltose, oligosaccharides, available starch, resistant starch and dietary fibre. Very few tables reach this level of detail and these substances are aggregated according to varying criteria.

In the UK, the food composition tables are based on the McCance and Widdowson’ The Composition of Foods, 6th edition and the software Diet Plan 6. The UK food tables have limitations because of accuracy of data, time changes, entry of new foods, variations in post harvest values, microwaving/steaming values are not included and most foods are frozen before it is analysed. However, the most practical problem I have encountered of the UK food tables is that it needs to be constantly updated, since there are new foods entering the UK diet each year. Also, a known major source of error in food tables also comes from the estimation of nutrient intakes. For example, calcium intake varies for all people in different ages and gender. For people with lactose intolerance, they should be provided with several options of food sources that do not have dairy ingredients. Making these updates and pairing up the people with appropriate diets can be a gargantuan task that must be balanced in a way that virtually all people can benefit from these food tables.

In constructing food tables for Sudan and Turkey, I would suggest a food composition table that has high calcium because milk consumption in these areas is not common, unlike in Scandinavian countries. Recommending a food table that has different sources of calcium, other than milk, can also be helpful to raise their awareness about the ilk of calcium deficiency. Since these countries are composed mostly by Muslim people, the food tables should also stay away from products that use pork or products derived from it. In constructing food tables, you should not only consider the nutritional values of food, but you should be aware of the cultural preferences.

Source:

Leclercq, C., Valsta, L.M. and Turrini, A. 2001. Food composition issues – implications for the development of food –based dietary guidelines, Public Health Nutrition, 4, 677-82.