Nutritional Needs

In recent years obesity has become a major problem. Consequently, the aim of some food manufacturers has shifted to producing products with a lower energy content. The energy content of a food can be reduced by using non-metabolised ingredients, reducing the density, or 

1 Special Nutritional Needs. Several groups have special nutritional needs, e.g. children, the elderly, pregnant women, manual workers and athletes. There are groups who have medical special needs such as those with allergies or diabetes. The latter groups need special foods that are, sometimes, outside ordinary food regulations and, therefore, have special exemption from them. 

If more energy is expended than is consumed then the energy will be provided from the body s food stocks. This will obviously cause the subject to lose weight. A vast industry has grown from this simple observation the slimming business. Slimming diets abound, in some cases supported by books, clubs and special foods. 

Nutrients taken into the body via the diet can have different metabolic fates— catabolism or anabolism. 

Catabolism refers to metabolic processes by which nutrient molecules are degraded to simple products (waste) in order to extract enei.  

Anabolism encompasses the synthesis of complex macromolecules and structures from building blocks derived from nutrients as well as synthesis of the building blocks themselves, such as nonessential amino acids. 

Catabolism and anabolism are often inversely regulated to provide balance for maintenance of the body s basal metabolic rate and to enable specific physiologic functions of organs. 

Nutritional balance and dietary intake have a major impact on the health of human populations. 

---

When normal enteral feeding in not possible or is inadequate to meet an individual s nutritional needs, intravenous (IV) nutritional therapy or total parenteral nutrition (TPN) is required. Products used to meet the IV nutritional requirements of the patient include protein substrates (amino acids), energy substrates (dextrose and fat emulsions), fluids, electrolytes, and trace minerals (see the Summary Drug Table Electrolytes). 

The nutrition needs of the future will be met with more limitations than in the past on the use of energy and restrictions on contamination of the environment. The maintenance of natural resources will receive much more attention than in the past. Concerns will increase regarding desertification, deforestation, urbanization, salinification, soil and water degradation, and atmospheric pollution. There is considerable difficulty in delineating these limitations, particularly as one considers the responsibilities and interests of developed and developing countries. The role of economics offers an additional challenge in working out these relationships. 

Assess nutritional needs and recommend appropriate supplementation. When the patient is tolerating an oral diet, determine if any parenteral medications can be switched to the oral route. 

The baking industry has even developed soft grain breads and other multigrain breads to supply consumers nutritional needs. 

In mammals, large differences are evident between and within species in resistance to zinc poisoning and in sensitivity to zinc nutritional needs (Table 9.9). Adverse effects of excess dietary... 

The nutritional needs of the majority of patients can be adequately addressed with enteral supplementation. Patients who have severe disease may require a course of parenteral nutrition. 

The goals of nutrition assessment are to identify the presence (or risk) of developing undernutrition and complications, estimate nutrition needs, and establish baseline parameters for assessing the outcome of therapy. 

The application of antioxidants in foods for infants and young children and for particular nutritional needs is regulated by Directive 89/398/EEC. Antioxidants permitted in weaning foods for infants and young children in good health are listed in Table 12.8. 

The concept of biochemical individuality has become part of most contemporary clinical and experimental medical and nutritional research. People are now known to fit into personally unique biochemical profiles based upon their own genetic structure, nutrition and environment.5 There is no such thing as a truly "normal" individualmeaning average. We are all biochemically unique and need to be dealt with as such. The Recommended Dietary Allowances (RDAs) which were developed by the Food and Nutrition Board of the National Research Council to establish the nutritional needs of "practically all healthy people" were not based upon the more recent information concerning the range of biochemical individuality among individuals. The RDAs that describe "normal" nutritional needs have questionable relevancy to the concept of optimal nutrition based upon individual needs. The contributions of Dr. Williams have opened the door for personally tailored nutritional and medical interventions that take biochemical individuality into account. 

Dr. Williams made this complicated story easy to understand and compelling to health scientists and the general public alike. His clarity of thought and language helped open up this field which had been dominated by Mendelian thinking for nearly one hundred years before the publication of Biochemical Individuality. In one of his lectures at which I was in attendance he responded to an inquiry as to why the RDAs were not sufficient to define a person s nutritional needs with the simple insight, "Nutrition is for real people. Statistical humans are of little interest."... 

Individuality in nutritional needs is the basis for the genetotrophic approach and for the belief that nutrition applied with due concern for individual genetic variations, which may be large, offers the solution to many baffling health problems. This certainly is close to the heart of applied biochemistry. 

The subject of variation with which we are predominantly concerned is, therefore, an old one, and it might be supposed that there would be little new to say. It is our opinion, however, based upon the data presented in this volume, that variability is vastly more important in the biological sciences and in medicine than it is currently assumed to be. And, because of what a study of variability in nutritional needs can do for medicine, such study deserves ten times more direct attention in terms of research time and effort than it is now receiving. The reader must be left to judge for himself whether these opinions are based upon a reasonable interpretation of the facts. 

At this time when proteins are receiving so much attention from various angles, it is necessary to bear in mind the high probability that nutritional needs for proteins and specific amino acids vary substantially from individual to individual. 

Before discussing the problem of self-selection of foods and its relationship to individuality in nutrition, we should emphasize at this point that individual differences in nutritional needs may have many basic causes. 

We have stressed the direct relationship of specific nutritional needs to enzyme building, but this is only one possibility. In the case of nicotinamide, for example, which in the form of coenzymes I and II functions in oxidation-reduction reactions, an individual s need may be great because of the genetic ineffectiveness of the mechanism for building nicotinamide into enzyme systems, but the difficulty may lie at another site. Possibly there is difficulty in digestion (of the combined forms) or more likely absorption, which precludes the individual from getting a substantial portion of the nicotinamide out of his food to the cells that need it. Even the mechanism for transport may be at fault. We wish to emphasize that the effectiveness or ineffectiveness of the structures and mechanisms which may be... 

We cannot take the space here to review the rather extensive literature dealing with self-selection of food this subject has been discussed elsewhere.87,88,89 Instead, we will summarize present-day knowledge of the subject, particularly as it relates to the problem of individual nutritional needs. 

The fact that each inbred strain of animals has not only a distinctive tendency to drink alcohol but also a distinctive excretion pattern makes it seem certain that we are here dealing with individual differences (quantitatively speaking) in nutritional needs. It seems evident that when rats are given plenty of everything they need nutritionally they shun alcohol, and that the reason why some shun it less than others is that their requirements for certain items are higher, and they... 

Recent experiments from our laboratory93 show that the same general principle holds with respect to sugar consumption. Rats on nutritionally deficient diets, when given a choice, consume more sugar than those which have their nutritional needs better satisfied. 

How far the significance of these animal experiments can be translated into human terms is a question we will not discuss here. It is worthy of note, however, that these experiments give strong corroboration of the central ideas of this chapter, namely, (1) each human individual has quantitatively a distinctive pattern of nutritional needs, (2) from individual to individual, specific needs may vary several-fold, and (3) important deficiencies may exist which have not been discoverable clinically by observing acute outward symptoms. 

In the preceding chapter we have assembled evidences that each individual s nutritional needs are also distinctive from the quantitative standpoint. Although every nutritionally important mineral, amino acid, and vitamin is needed by every individual, it followsif biochemical individuality existsthat the needs are quantitatively distinctive for each individual. Evidence has been presented in the preceding chapter that this is actually the case and that the divergences for many items are wide. 

The genic pattern of a fertilized egg cell determines what the developing embryo is going to need during the course of its development. In certain species of mammals (e.g., rats), the over-all nutritional needs are qualitatively different from those of other species (e g., guinea pigs). In each individual within the human species, the needs are quantitatively different. 

A basic idea which arises out of the material presented in this volume is a very simple one Understanding and appreciating what heredity distinctively does for an individual may make it possible to cope environmentally with his difficulties. Without the appreciation of what heredity does, it is impossible to make intelligent use of the available environmental influences. Narrowing down the discussion specifically to the genetotrophic principle Unless we know about the distinctive nutritional needs imposed by one s heredity, we are in no position to meet these needs. We cannot know about these needs without studying individual differences in needs. We must be aware of the general facts of biochemical individuality, and in specific cases we must know the needs of the individuals whom we would help. 

When we pay attention to differencesanatomical, physiological, and biochemicalwe are inevitably led to consider differences in nutritional needs. It is then but a small step to the genetotrophic idea. 

There is one possible obstacle to the application of the genetotrophic concept which should be mentioned at this point. In our discussion of nutritional needs, we have in general made the tacit assumption that they are additive. 

From the standpoint of biochemical genetics and the genetotrophic principle, however, it seems likely that partial genetic blocks (which impose increased demands) may happen anywhere in the entire metabolic scheme in what may be assumed, without further evidence, to be in a random fashion. If this be the case, any and every nutritional need may be represented among those which are observed to be augmented. 

Another interesting possibility presents itself in this connection. We have assumed all along, tentatively at least, that all individuals within the same species have qualitatively the same nutritional needs. This, in effect, may not be true, as we have hinted in connection with our discussion of amino acid needs. It is within the realm of possibility and even probability that certain amino acids, e g., glutamic acid, glutamine, or arginine, may be "essential amino acids" for certain individuals in the sense that they are essential for health... 

---