| Immunonutrition:
fact, fantasy, and future.
Reference:Curr Gastroenterol
Rep 2002 Aug;4(4):332-7
Immunonutrients are
molecular compounds that, while being dietary components, also influence
immunologic response mechanisms. Substances such as glutamine, w-3 fatty
acids, arginine, and/or ribonucleic acid have been added to standard nutritional
support solutions, and the use of these formulations is known as "immunonutrition."
A number of randomized, controlled trials have demonstrated that recipients
of immunonutrition have better outcomes than control subjects receiving
standard nutritional support. However, it is possible that standard parenteral
or enteral nutrition is actually harmful. We currently lack data from randomized
trials showing the efficacy of immunonutrition compared with no nutritional
support. Even if such information were forthcoming, these immunonutrients
may simply be acting as pharmacologic agents. Finally, because each of
these nutritive agents may either up- or downregulate the immune response,
the effects may be disease-state specific.
Immunonutrition
in experimental colitis: beneficial effects of omega-3 fatty acids
Reference: Arq Gastroenterol
2002 Jan-Mar;39(1):48-5
BACKGROUND: Recent data
have given emphasis to the benefits of immunonutrition with omega-3 fatty
acids (n-3 FA) in various clinical situations. This work presents the results
of parenteral administration of different lipid emulsions in experimental
acute colitis and reviews the pertinent literature.
METHODS: Seventy-four
adult male Wistar rats were randomized in six groups that had 10% acetic
acid-induced colitis (except CS). During 7 days, control groups CS (without
colitis) and CC (with colitis) received physiological solution and the
others received specific lipid emulsion by a central venous catheter (0.5
mL/h). The n-3/n-6 FA ratio and lipidic compositions were: group L--1:7.7
(LCT, n = 12), M--1:7.0 (MCT and LCT, n = 12), LW-3--1:4.5 (LCT plus FO,
n = 12) and MW-3--1:3.0 (MCT and LCT plus FO, n = 13). Rats were evaluated
to assess abdominal and intestinal alterations, macrophage cellularity
and colonic concentrations of LTB4, LTC4, PGE2 and TXB2.
RESULTS: N-3 FA treated
rats (LW-3 and MW-3) presented less inflammatory abdominal alterations
than CC rats. Mucosal ulcer formation in MW-3 group was the only comparable
to CS group. Only CS, M and MW-3 rats presented smaller cellularity than
CC group. Comparing to CC group, there were found smaller averages of LTB4
in CS, LW-3 and MW-3 groups, of PGE2 in CS, M and MW-3 groups, and of TXB2
in CS and MW-3 groups. LTC4 averages were not different.
CONCLUSIONS: 1) LCT-containing
lipid emulsion with low n-3/n-6 ratio do not modify inflammatory colitis
derived manifestations; 2) the association of MCT/LCT-containing lipid
emulsion with fish oil with high n-3/n-6 ratio impels great beneficial
impact, attenuating morphological and inflammatory consequences and decreasing
colonic concentrations of proinflammatory mediators.
Hypocaloric
jejunal feeding is better than total parenteral nutrition in acute pancreatitis:
results of a randomized comparative study.
Reference: Am J Gastroenterol
2002 Sep;97(9):2255-62
OBJECTIVES: The aims
of this study were to define the indications for, and to evaluate the cost-effectiveness
of, nutritional support in patients with acute pancreatitis.
METHODS: All admissions
during the 12-month period from January through December 2000, were entered
into a common management protocol consisting of an initial 48-h fast with
i.v. fluids and analgesics. After 48 h, those patients who were improving
were restarted on oral feeding (group O). The remaining patients were randomized
to receive nasojejunal (group EN) or parenteral feeding (group TPN). The
randomization study was continued until 50 patients had been accrued. Outcomes
in the three groups were compared with respect to length of hospital stay,
duration of feeding, complications, and hospital costs.
RESULTS: A total of
156 admissions were evaluated in the first 12 months. Of these, 87% patients
had mild disease, 10% moderate, and 3% severe; 62% were related to alcohol
abuse, 18% gallstones, and 8% idiosyncratic drug reactions. Of the patients,
75% improved on 48 h bowel rest and i.v. fluids, and were discharged within
4 days. The remainder were randomized to jejunal elemental (n = 26) or
parenteral (n = 27) feeding. Duration of feeding was shorter with EN (6.7
vs 10.8 days, p < 0.05) and nutrition costs were lower, representing
an average cost saving of $2362.00 per patient fed. EN was less effective
in meeting estimated nutritional requirements (54 vs 88%, p < 0.0001),
but metabolic (p < 0.003) and septic complications (p = 0.01) were lower.
Subgroup analysis of patients with severe disease showed similar findings.
CONCLUSION: Despite
concerns that metabolic expenditure is increased and that food-stimulated
pancreatic secretion might exacerbate the disease process, hypocaloric
enteral feeding seems to be safer and less expensive than parenteral feeding
and bowel rest in patients with acute pancreatitis.
Therapeutic Lifestyle
Change and Adult Treatment Panel III: Evidence Then and Now.
Reference: Curr Atheroscler
Rep 2002 Nov;4(6):433-43
The Third Report of
the National Cholesterol Education Program's Adult Treatment Panel (ATP
III) has an extensive section on nonpharmacologic therapy for those with
abnormal blood lipids. ATP III focused on the high-saturated fat atherogenic
diet, obesity, and sedentary lifestyle and recommended a program of therapeutic
lifestyle change (TLC). This review discusses several issues, including
1) why ATP III changed from the Step I and Step II diets to TLC; 2) the
benefits of keeping trans fatty acid intake low and the addition of viscous
fiber and plant stanol/sterol esters to reduce low-density lipoprotein
cholesterol beyond that seen with the Step II diet; 3) the de-emphasis
on total fat and a sharper focus on the kinds of fat ingested in the new
guidelines; 4) the endorsement of regular physical activity and weight
loss as important first steps in reversing the unwanted metabolic effects
of the metabolic syndrome; and 5) the emphasis of health-promoting aspects
of the diet that include, among other things, fish and omega-3 fatty acids.
At all stages of TLC, ATP III encourages the referral to registered dietitians
or other qualified nutritionists for medical nutrition therapy. TLC and
the ATP III guidelines should provide guidance to practitioners who wish
to get low-density lipoprotein cholesterol to goal (whether or not drugs
are used), prevent or treat the metabolic syndrome, and improve the overall
health of the patient.
|
Immunonutrition:
fact, fantasy, and future.