Optimisation of Food Nutrient Composition

Abstract

The nutrients in foods can be made to be in the best amounts by four ways now that the approximate requirements of the most important nutrients are known. 1. The approximate daily requirements of a man could be incorporated in a food such as a biscuit so that eating one daily would satisfy his nutritional needs except for energy. 2. Foods can be enriched by deliberately adding nutrients, or nutrients can be removed from foods that have undesirable amounts. Chemical additives, whether intentional (such as salt) or incidental (such as hydrocarbons from smoking of foods) have an ancient history. With the synthesis of vitamins and discovery of deficiencies of these and of trace elements, intentional additives have become more nutritionally significant. There are three main reasons for such intentional additions. (a) Nutrients lost in the preparation of a food may be restored. The addition of thiamin to white flour is an example. (b) Nutrients may be added to a food that would be expected to contain them. Since margarine is a substitute for butter, vitamins A andD are added by law in the approximate amounts present in butter. (c) Foods may be used as a vehicle for nutrients when supplementation of the diet is desirable to avert deficiencies. An excellent practice is the iodisation of salt provided uniodised salt is also available at the same price for those who specifically request it. The liberty of the individual is not infringed by these practices: he can choose wholemeal bread or butter or uniodised salt if he objects to the enforced additives. To use a public water supply as a vehicle for substances thought to be beneficial to physiological processes in the body is unethical mass-medication, even if such a substance is being adjusted to an alleged ‘optimum’ concentration; the optimum concentration for any such substance is zero. 3. Improvement of nutrients in foods can be achieved by (a) selective breeding of animals or plants, (b) different methods of feeding them, or (c) by improved methods of manufacture of foods. An example of the second is the production of butter relatively rich in cis-linoleic acid by feeding to cows protein-coated capsules of sunflower seed oil. An example of the third is the retention in margarine of the same essential fatty acid. 4. The amounts of nutrients in foods can be improved by choosing the right combinations of foods. The content of essential amino acids in plant foods can be improved by blending different ones, such as wheat and soyabean. The best pattern of different foods in the British diet is briefly discussed in relation to the provision of the best amounts of nutrients in the diet.