Careers in Nutrition from the Clinical Viewpoint by George L. Blackburn, M.D., Ph.D. and Bruce R. Bistrian, M.D., M.P.H., Ph.D.
major impediment to clinical careers in nutrition is the widespread lack of appreciation for the role of nutrition in clinical practice. This is best exemplified on the clinical level by the failure in American hospitals to recognize or to treat effectively adult protein-calorie malnutrition (PCM). Protein-calorie malnutrition is not an isolated problem; the widespread prevalence of malnutrition has been identified’ and confirmed.2 In a recent one day survey of the nutritional status of surgical patients3 nearly 50 percent of those hospitalized were moderately or severely malnourished. The criteria used were serum albumin (SA), triceps skinfold (TSF) and arm muscle circumference (AMC) measurements, but not weight-for-height (W/H) ratio (Figures 1 and 2). To confirm these findings we conducted three similar surveys at weekly intervals of medical patients in the same hospital; hematologic values were part of the nutritional profile.4 In an attempt to determine the effect of conventional nutritional support, the dietary intake of patients for the week preceding each survey was also recorded. Similar degrees of PCM were found, although calorie depletion (TSF, W/H) was significantly more common, and protein depletion (AMC, SA) significantly less severe in the medical patients. Interesting-
Or. Blackburn is Director and Or. Bistrian is Assistant Director of the Nutrition Support Service, Cancer Research Institute, New England Deaconess Hospital, 194 Pilgrim Road, Boston, Massachusetts 022 15. A limited number of reprints of this article may be obtained from the author. THERE ARE NO REPRINTS OF UNSIGNED REVIEWS.
ly, the nutritional support which patients received did not change their nutritional status. While much emphasis is given to inadequate recognition and support for nutrition in medical education, the fact is that there are not enough teachers knowledgeable in PCM to expose this problem. The time given to nutrition is squandered on subjects irrelevant to clinical medicine in the U.S. such as vitamin deficiencies. PCM on the other hand is a difficult disease to treat and calls for teaching material not readily available in Western medical textbooks.
Techniques of Nutritional Assessment It is necessary to apply newer techniques of nutritional assessment developed for children in nonindustrialized societies to hospitalized adults in the U S 6 These more sensitive and meaningful techniques include anthropometric measurements like triceps skinfold and arm muscle circumference,7 serum protein levels such as serum albumin,e transferrin or ironbinding capacity9 and tests of immune function.1°-12 The creatinine-height index developed by Viteri13 can also be a useful index of depletion of lean body mass in adults.14 Coupled with an inability to recognize the prevalence of this disease, however, is the lack of understanding of the profound detrimental effect of malnutrition on host response to illness.l5 The failure to see the similarities between the child with marasmus due to the unavailability of food and the cachectic adult whose primary disease prevents food intake or utilization limits the teacher of nutrition who is seeking objective support for the thesis that nutrition is an important discipline for the medical student or practitioner. The child with NUTRITION REVIEWSIVOL. 3 4 , NO. 41APRIL 1976
Figure 1 Anthropometric estimates of nutritional status (welghtlheght) and body fat stores (tr\cep skintdd) in surveys of medical and surgical patients in an urban municipal hospital Medical patients were more commonly depleted by these two measures reflectma calorc dehcits
Figure 2 Anthropometric estimates of lean body mass (arm muscle circumference) (AMC) and estimate of visceral protein status (serum albumin) in medical and surgical nutntional surveys Surgical patients were more severely depleted than medical pahents by these measures of protan status
NUTRITION REVIEWSIVOL. 34. N O . 41APRIL 1976
kwashiorkor, developing in a setting of infection and carbohydrate-containing, low-protein diets, bears important similarities to the catabolic adult receiving 5 percent dextrose infusions as routine nutritional support.16117 Specific similarities include the preservation of anthropometric measurements in the presence of lower serum albumin levels, depressed peripheral lymphocytes, apergy, decreased antibody response to stimulation and lymphocyte transformation to mitogens and the improvement of all these parameters upon nutritional repletion.18 In most hospitalized patients, whatever the underlying problem, the consequence of ignoring nutrition, even for a short period of time, can result in malnutrition characterized by negative nitrogen balance and significant elec-
QUAR T/LE fsf
trolyte and mineral Iosses.5 Patients with moderate degrees of malnutrition at the onset of of their illness require sophisticated counseling and treatment to avoid unnecessarily prolonged sickness and even death.6>18Techniques for the treatment of PCM are complex; the response is slow and does not occur in the face of continued stress present in a strongly catabolic hormonal ~ e t t i n g . l g !This ~ ~ is demonstrated by our efforts to treat pancreatitis using a new approach that focused on nutritional support. The average period required to restore serum protein levels (albumin) and competency of host defense (total peripheral lymphocyte count) was Pen weeks. While weight loss was arrested, no substantial increase in weight occurred (Figure 3); however, the response to nutritional support can be dra-
Status due to disease Status after therapy
I WEIGKT CHANGE
z coefficient of variance
TRICEPS MID-ARM ALBUMIN LYMPHOCYTES SKIN FOLD MUSCLE CIRCUMFERENCE
Figure 3. Anthropometric measurements reveal substantial nutritional depletion, particularly of the muscle compartment (AMC) and visceral protein status (albumin and lymphocytes). Nutritional therapy prevented further weight loss and significantly restored the visceral protein compartment. This is characteristic of enteral feeding in contrast to parenteral feeding. While weight loss was prevented, in general it is a poor reflection of early effects of the nutritional therapy.lg Reprinted from J. Surg. Res. 78:477-483, 1975.
NUTRlTlON REVIEWSIVOL. 3 4 , NO. 41APRIL 1976
matic and indeed life-saving. The above group of patients underwent surgery without any significant time-delaying complications where the major complication rate is generally 9.2 percent. Defined Formula Diets Developments in defined formula diets and total parenteral feeding represent major medical advances that rank with the discovery of antibiotics, heart-lung bypass pumps and renal dialysis in their influence on the survival.21 In certain conditions such as inflammatory bowel disease,24 fistulas of the alimentary tract,23 acute and chronic pancreatitis’g and acute renal fail~re,~5 enteral and parenteral hyperalimentation have become the primary mode of therapy. In others, particularly cancer, optimal nutritional support has been a useful adjunct to primary immuno-, chemo- or radiotherapy.26,27 The proper use of this new therapy, however, is a sophisticated science; satisfactory results are a consequence of an understanding of nutritional biochemistry and metabolism. The practitioner responsible for this therapy must have proper training and use that knowledge almost daily in order to avoid complications and provide the best care for each patient.5 Nutritional Support Service Our concern with the poor nutritional status of hospitalized patients and a lack of nutritional knowledge both in the diagnosis and treatment of malnutrition led to the development of a Nutrition Support Service.6 The ultimate goal of this service is to monitor the nutritionalstatus of all hospitalized patients, to consult and/or supervise the appropriate therapeutic support in selected patients, and to provide a multidisciplinary approach to the nutritional problems that arise in the hospital. Particularly with the advent of total parenteral nutrition (TPN) has the need for a team approach and standard guidelines become essential so that dangerous complications-sepsis, pneumothorax, hyperosmolarity-can be minimized. A Nutritional Support Service should combine the services of nursing, dietetics, pharmacy and physical therapy with the major clinical disci100 NUTRITION REVIEWSIVOL. 34, NO. 41APRIL 1976
plines to encourage the treatment of proteincalorie malnutrition. The operation of the Nutritional Support Service is greatly aided by the procurement of objective data with which to make a nutritional assessment and formulate a nutritional prescription. The “input” data is shown in Table 1. The “output” is derived from a variety of formulas and nomograms incorporated into a computer program which includes the basal energy expenditure (BEE) based on HarrisBenedict standards.22 By considering four variables (weight, height, age, sex), these standards allow better adjustment not adequately covered by formulas using weight alone. In states of mild to moderate catabolism where restoration of lean body mass is required, delivery of standard total parenteral alimentation at 1.75 times BEE will produce positive nitrogen baIance.z2 Enteral hyperalimentation to produce similar nitrogen balance is achieved at calorie intake of 1.54 times BEE. If only maintenance of lean body mass is desired, less protein and calories are required as shown in Table 1. This information together with the Nutrition Assessment Summary (Table 2) are maintained on the patient’s chart. They serve as an important reminder of the nutritional state of the patient and the need for adequate nutritional support to restore deficiency, particularly of the kwashiorkor-likevariety manifest by depression in serum albumin, transferrin, total lymphocyte count and immune competence. The use of these tables has been more fully described e l s e ~ h e r e . ~ ~ ? ~ ~ ~ ~ ~ Curriculum Development Besides patient care, clinical nutrition provides unlimited research opportunities in basic and clinical sciences. Recent advances in total parenteral alimentation,2* defined formula diets29and protein-sparingtherapies in starvation,3O opened up numerous avenues for research. This includes the creation of products, delivery systems and techniques for nutritional support along with investigations into the metabolic response to disease and its successful manipulation. Research of this type would in-
volve work in nutritional biochemistry and metabolism, clinical nutrition and food technology along with the general research tools of modeling, statistics and data processing. This em-
Table 1 Computerlcalculator determination of protein and calorie requirement for nutrition maintenance or anabolism either orally or parenterally. Estimates based on surface area plus age and sex.22 DATA FED INTO COMPUTER 1. 2. 3. 4. 5. 6.
Height-Inches Weight (Usual) Ibs. Frame Type (Ring) small, medium, large Weight (at Rx) Ibs. Weight (Ideal) Ibs. Surface Area M2 (See table. Based on weight at Rx)
COMPUTER FEED BACK Height cm. (in x 2.54) Weight (Usual) kg. (Ib. x 2.2) Weight (at Rx) kg. (Ib. x 2.2) Weight (Ideal) kg. (Ib. x 2.2) Usual Weight - Ideal Weight Weight at Rx - Ideal Weight Weight at Rxildeal Weight % Weight at Rx/Usual Weight Ol0 Basal Energy Expenditure kcal / 24 hrs. kcal / Hr/ M2 Anabolic Requirements Kcals/24 hrs. I.V. (B.E.E. x 1.76) kcal Oral (B.E.E. x 1.54) kcal Nitrogen Anabolic Requirements/24 hrs. I.V. (kcals - 150) g Oral (kcals t 150) g Protein (Amino Acid) Requirements/24 hrs. I.V. (N x 6.25) g Oral (N x 6.25) g Maintenance Requirements Kcals/24 hrs. Oral (B.E.E. x 1.22) kcals Nitrogen Maintenance Requirementd24 hrs. Oral (kcals + 300) g Protein (Amino acid) Requirementsl24 hrs. Oral (N x 6.25) g From Nutrition Support Service, New England Deaconess Hospital. Reprinted from J. Surg. Res. 18:477-483, 1975.
phasizes the necessity of a multidisciplinary approach if modern medical research is to be fruitful. These areas of research, however, are presently being explored by a small group of physicians from various clinical disciplines, for whom clinical nutrition is an avocation and not a specialty.3’ The solution to this present situation is the education of physicians in nutrition at all stages of their training. Those responsible for graduate medical education must re-establish priorities of what will be taught given the limited time and support available. The first priorities for the clinical nutritionist are to design a curriculum that will “sell” to today’s students, and to provide a recognizable (and remunerable) clinical service that will demonstrate the relevance of nutrition in their future practice. If these are accomplished, additional specialists should be attracted. Then will they be able to make a living rather than a hobby out of such interests. Nutrition as a specialty can resume the major role it held prior to the discovery of antibiotics and insulin, a time when it represented the major therapeutic tool possessed by all physicians. Because nutrition cuts across most specialties, core teaching, which is so popular among medical students today, is ideally suited for nutritional education concerning protein-calorie malnutrition. In other disorders with a major nutritional component, for example, infectious disease, cancer, trauma, diabetes, obesity, instruction should concentrate on nutrition and its effect on metabolism. The teaching of metabolism, particularly the influence of “energy substrates” on organ function, proved to be the most effective pedagogical approach to the science of nutrition. Unfortunately, metabolism has become almost as neglected as nutrition. Fluid and electrolytes, acid-base balance and substrate-hormone interactions no longer appeal to the traditional disciplines usually called upon to teach them. The result is that many physicians are unable to provide sophisticated “molecular support” to patient care. Relating physiological biochemistry to the hospitalized patient, particularly in terms of optimal nutritional support, produces visible results. Thus it is very effective in student teaching. Not only is the quality NUTRITION REVIEWSIVOL. 34, NO. 41APRIL 1976
Table 2 Nutritional Assessment and Metabolic Status form for clinical studies. This detailed assessment will allow accurate interpretation of the role of nutrition in clinical studies. Nitrogen Maintenance Requirements/24 hrs. CakN Ratlo 3Oo:l 90% 60-90% 60%
STANDARD PARAMETERS Oral (kcals + 300) g Weight/Height
Protdn (Amino Acids) Maintenance Requirements Oral (N x 6.25) g
24 hr. Anabolic Requirements Standard Hyperailmentation (TPN) or high N defined formula 1 mi = 1 calorie diet (DFD) Ca1:N 15Q:l 4. 25% Amino acids 25% Glucose - TPN High N DFD
mls (=Anabolic IV kcal) mls (=Anabolic Oral kcal)
24 hr. Maintenance Requirements Oral Ca1:N 300:l Standard DFD
mls (=Maintenance kcals)
Triceps Skinfold Mid Upper Arm Circumference Mid Upper Arm Muscle Circumference Albumin Creatinine Height Index Lymphocyte Count Iron Binding Capacity/ Transferrin Cellular Immunity SKiSD Other
PERCENTAGE STANDARD NUTRITIONAL PARAMETERS Nutritional or Metabolic Status (Check) Triceps Skinfold Mid Upper Arm Circumference Mid Upper Arm Muscle Circumference Albumin Creatinine Height Index Total Lymphocyte Count Transferrin
CELLULAR IMMUNITY SKIN TESTING EXPRESSED AS mm PERCENTAGE NORMAL REACTION (read all reaction 2mm, standard = 5mm) Candida (Hollister-Stier) & Varidase (Lederie) 1 ml of solution diluted 1:1QQ immediate fa]24 hrs. @ 48 hrs.
immediate ti 24 hrs (n 48 hrs
Dlnitrochlorobenzene Contact Sensitization
goo/=Standard 60-90% 60% Standard
Not Depleted Moderately Depleted Severely Depleted
TYPE OF PROTEIN CALORIE MALNUTRITION(CHECK) Acute Visceral Attrition (Kwashiorkor-like) (Wt/Ht, TSF, AC, AMC, CHI preserved; Albumin and Transferrin acutely depressed) Adult Marasmus (Cachexia) (Wt/Ht, TSF, AC, AMC, CHI depressed; Albumin and Transferrin preserved until late) Intermediate States Acute Visceral Attrition Superimposed on Adult Marasmus (Wt/Ht, TSF, AC, AMC, CHI depressed; Albumin and Transferrin rapidly and acutely depressed)
@ 24 hrs., GL 10-14 days
2,000 pg 50 CLg 50 p g (Challenge Dose) If positive at 2,000 p g or 50 Fg site at 10-14 days without challenge, consider 90% If positive only on challenge, consider 60-90%
From Nutrition Support Service, New England Deaconess Hospital. 102 NUTRITION REVIEWSIVOL. 34, NO. 4IAPRIL 1976
of existence enhanced but morbidity and mortality can be significantly reduced. The proverbial competition between medicine and surgery will abate in this neutral ground of nutritional support.32 If you will, nutrition might be seen as a “United Nations” where many disciplines come together in teaching, patient care and research.
Summary If the field of nutrition is to stay abreast of the times and obtain the interest, respect and curriculum support it deserves, it must establish its importance as a clinical speciality. A nutritional support service is the ideal vehicle to exemplify nutrition’s role in curative medicine. While delivering patient care, a nutritionally characterized and closely documented patient population provides an excellent base to further knowledge in clinical medicine. The metabolic consequences of severe illness oblige us to employ a diet therapy with maximum leverage to improve the quality and likelihood of recovery. Unfortunately, the lack of sufficient knowledge prevented a general recognition of the extent of the problems involved in hospital dietary deficiencies and of the techniques for reversing those discrepancies. The multifaceted aspects of a nutritional support service in patient care, education and research, however, lead to an increased awareness of the importance of nutritional support and to a greater application of optimal nutritional care for the hospitalized patient. 0
1. C.M. Leevy, L. Cardi, 0. Frank, R. Gellene and H. Baker, Am. J. Clin. Nutrition 17: 259-271, 1965 2. A.J. Bollet and S.O. Owens, Am. J. Clin. Nutrition 26: 931-938, 1973 3. B.R. Bistrian, G.L. Blackburn, E. Hallowell and R. Heddle, J. Am. Med. Assn. 230: 858-860, 1974 4. B.R. Bistrian, G.L. Blackburn,J. Vitale, D. Cochran and J. Naylor, J. Am. Med. Assn. (in press) 5. G.L. Blackburn and B.R. Bistrian in Surgical Clinicsof North America. G.H.A. Clowes, Editor. (in press) 6. G.L. Blackburn and B.R. Bistrian in Nutritional Support of Medical Practice. H.A. Schneider, Editor. Harper & Row (in press)
7. D.B. Jelliffe: The Assessment of the Nutritional Status of the Community. World Health Organization, Geneva, 1966 8. R.G. Whitehead, W.A. Coward and P.G. Lunn, Lancet 1: 63-66, 1973 9. H.S. McFarlane, MI. Ogbeide, S. Reddy, K.J. Adcock, H. Adeshina, J.M. Gurney, A. Cooke, G.O. Taylor ana J.A. Mordie, Lancet I: 392394, 1969 10. P.M. Smythe, M. Schonland, G. Brereton-Stiles, H. Grace, W.E.R. Loening, M.A. Parent and G.H. Vos, Lancet II: 939-943, 1973 11. E. Sellmeyer, E. Bhettay, A. Truswell, 0. Meyers and J. Hansen, Arch. Dis. Child. 47: 429-435, 1972 12. J. Geefhuysen, E.V. Rosen, J. Katz, T. ipp and J. Metz, Brit. Med. J. 4: 527-529, 1971 13. F.E. Viteri and J. Alvarado, Pediatrics 46: 696706, 1970 14. B.R. Bistrian, G.L. Blackburn, M. Sherman and N.S. Scrimshaw, Surg. Gynec. Obstet. 141: 512-516, 1975 15. N.S. Scrimshaw, C.E. Taylor and J.E. Gordon: Interactions of Nutrition and Infection. World Health Organization Monograph Series No. 57, Geneva, 1968 16. G.L. Blackburn, J.P. Flatt, R. Heddle and J.G. Page, Sir David Cuthbertson’s Glasgow Injury Symposium Sept. 11 & 12, 1975 (in press) 17. B.R. Bistrian, G.L. Blackburn, N.S. Scrimshaw and J-P. Flatt, Am. J. Clin. Nutrition 28: 11471155, 1975 18. D.K. Law, S.J. Dudrick and N.I. Abdou, Surg. Gynec. Obstet. 139: 257-266, 1974 19. G.L. Blackburn, L.F. Williams, B.R. Bistrian, M.S. Stone, E. Phillips, E. Hirsch, G.H.A. Clowes, Jr. and J. Gregg, Am. J. Surg. 131: 114-124, 1976 20. G.L. Blackburn and B.R. Bistrian in Nutritional Support of Medical Practice. H.A. Schneider, Editor. Harper & Row (in press) 21. S.J. Dudrick, J.M. Long, E. Steiger and J.E. Rhoads, Med. Clin. N. Am. 54: 577-589, 1970 22. P. Rutten, G.L. Blackburn, J.P. Flatt, E. Hallowell and D. Cochran, J. Surg. Res. 18: 477483, 1975 23. J.E. Fischer, G.S. Foster, R.M. Abel, W.M. Abbot and J.E. Ryan, Am. J. Surg. 125: 165175, 1973 24. H. T. Randall in Modern Nutrition in Health and Disease. R.S. Goodhart and M.E. Shills, Editors. Lea & Febiger, New York, 1973 25. R.M. Abel, C.H. Beck, W.M. Abbot, J.A. Ryan, G.O. Barnett and J.E. Fischer, New Engl. J. Med. 288: 695-699. 1973 NUTRITION REVIEWSIVOL. 34, NO. 4IAPRIL 1976
26. E.M. Copeland, B.V. MacFayden, Jr., V.J. Lanzotti and S.J. Dudrick, Am. J. Surg. 129: 167173, 1975 27. G.L. Blackburn, B.R. Bistrian, A. Bothe and W.V. McDermott, Ann. Surg. (in press) 28. B. Maini, G.L. Blackburn, B.R. Bistrian, J.P. Flatt, J.G. Page, A. Bothe, P. Benotti and H.Y. Rienhoff, Jr., J. Surg. Res. (in press) 29. E.A. Young, N. Heuler, P. Russels and E. Weser, Gastroenterology 69: 1338-1345, 1975
30. G. L. Blackburn, J.P. Flatt and T. Hensle in Total Parenteral Nutrition. J. Fischer, Editor. Little, Brown & Co., Boston, 1976 31. D.B. Coursin, Am. J. Clin. Nutrition 27: 11951199, 1974 32. G.L. Blackburn, B.R. Bistrian and G. Page in Advances in Modern Nutrition. M.A. Mehlman, Editor. Hemisphere Publishing Co., 1976 33. C.F. Butterworth and G.L. Blackburn, Nutrition Today 10: 8-18, 1975
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