TYPES OF
ORAL SUPPLEMENT
Many types of oral
nutrition supplement are available in a wide choice of flavours. Most
are liquid sip-feeds but some come in other forms such as desserts. A full
description of all types is beyond the remit of this book and advice from
dietitians is often required. Nevertheless, the IVN prescriber should know the
basics of what is available and understand the rationale behind different supplement
use.
Most commercial oral
supplements contain energy, protein, vitamins, trace elements and fluid, with
some containing fibre. They are usually nutritionally complete if used alone to
meet all of a patient’s energy needs. Most contain 1.0 kcal/mL but
higher-energy versions containing 1.5 kcal/mL are also available. Nitrogen
content is usually equivalent to 4–6 g protein per 100 mL but they vary widely
in energy to- protein ratios, nitrogen form and content, and the type of fat
that they contain. The following broad types are commonly used:
·
Polymeric complete: polymeric feeds containing nitrogen as
whole protein or long polypeptides are most commonly prescribed. The 8 Oral
and enteral tube support carbohydrate source
is mostly partially hydrolysed starch and the fat is predominantly long-chain
triglycerides (LCTs). These feeds tend to be either sweet, apparently milky
drinks or savoury formulas. They are suitable for patients who have no
significant digestive problems.
·
Polymeric fat-free: some polymeric oral supplements contain no lipid.
They are therefore less nutritionally complete but many patients prefer the
fruit drink-type format, particularly if the drink is diluted with water to
limit its sweetness.
·
Fibre-containing feeds: many oral supplements are available in standard
and fibre-enriched forms. The standard feeds contain little or no fibre and
hence they lead to little or no short-chain fatty acid (SCFA) production in the
colon. Fibre-enriched feeds theoretically increase SCFA availability in the
colon, which may increase salt and water reabsorption and limit growth of
pathogenic bacteria by lowering colonic pH. Their effectiveness, however, is
probably marginal, especially if patients are on antibiotics which reduce colonic
flora.
·
Predigested and elemental feeds: these feeds contain nitrogen as either
short peptides or, in the case of elemental diets, as free amino acids.
Carbohydrate provides much of the energy content while the fat content varies
in both quantity and the proportion provided as LCTs and medium-chain
triglycerides (MCTs). The aim of ‘predigested’ feeds is to improve nutrient
absorption but their effectiveness is usually limited to maldigestive problems
(e.g. pancreatic disease) rather than malabsorptive states. Indeed, they should
generally be avoided in patients with a short gut or patients with small-bowel
fistulae since their high osmolality can cause excess movement of water into
the gut and hence increased diarrhoeal losses.
·
Specialised disease-specific and
pharmaconutrient feeds: some
very specialised disease-specific and pharmaconutrient supplements are available
but the indications for their use are complex and beyond the remit of this
book. Sodium-supplemented sip-feeds are not available commercially but can be
very useful in the management of patients with high-output stomas who tend to
become salt depleted.
Indeed, the use of such
sodium supplementation can avoid the need for IVN in some patients and hence
their use must be understood by IVN prescribers (see Chapter 10).
Common
indications for enteral tube feeding
|
Indication
for feeding
|
Examples
|
|
Unconscious patient
|
Head injury, ventilated patient, encephalopathy
|
|
Swallowing disorder
|
Post cerebrovascular accident, multiple sclerosis,
motor neurone disease, Parkinson’s disease
|
|
Physiological anorexia
|
Liver disease (particularly with ascites), cancer
cachexia, especially in malnourished patient due to undergo surgery (since supplementary
feeding helps reduce postoperative complications)
|
|
Upper gastrointestinal obstruction
|
Pharyngeal tumour, oesophageal tumour/stricture,
pyloric stenosis
|
|
Partial intestinal failure
|
Postoperative ileus, inflammatory bowel disease,
short-bowel syndrome
|
|
Increased nutritional requirements
|
Intensive-care patient, cystic fibrosis,
renal disease
|
|
Psychological problems
|
Severe depression or anorexia nervosa
|
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