Factors Affecting Adherence, Intake, and Perceived Palatability of Oral Nutritional Supplements: A Literature Review.

Oral nutritional supplements (ONS) are a clinically effective and relatively inexpensive way to supplement the diet of patients with, or at risk of, undernutrition. Good adherence is a primary determinant of the effectiveness of ONS. However adherence can be problematic for those with the greatest clinical need, such as undernourished older adults. This review aimed to appraise the available literature for the factors (contextual, personal and product related) affecting patient adherence and perceived palatability of ONS, identify areas requiring improvement and uncover gaps in the evidence to guide the focus of future research. Contextual factors identified were healthcare staff and the timing of administration. Personal factors included sensory changes and motivation which alter experience of and desire to consume ONS. The product's sensory characteristics determined palatability and intake, but undesirable attributes, such as off-flavours, can stem from nutritional ingredients. The contribution made by aroma to older adults' experience of ONS was a comparatively under-researched area. Further research should address this evidence gap to optimise the flavour, aroma profile and palatability for undernourished older consumers, thereby optimising intake. A combined multidisciplinary effort involving strategic expansion of research, industry development and clinical practice should simultaneously address the factors identified, to provide the best approach to improve adherence.

The relation between stimulated salivary flow and the temporal consumption experience of a liquid oral nutritional supplement.

Use of oral nutritional supplements (ONS) in undernourished patients has proven clinical benefits, but this can be hampered by low adherence due to poor experience of palatability. Many patients, particularly older patients, experience hyposalivation which can cause taste changes and reduce the enjoyment of foods. The aim of this study was to investigate differences in the temporal consumption experience (comprising sensory perception, in-mouth aroma release and subjective appetite) of a clinically relevant portion of ONS, for groups differing in saliva flow rates (SFR). The SFR (mL/min) of thirty healthy individuals was measured on three occasions. This data was used to categorise individuals into three groups using quartile analysis: low flow (LF) (0.3-0.6 mL/min, n = 5), medium flow (MF) (0.7-1.2 mL/min, n = 16) and high flow (HF) (1.3-1.8 mL/min, n = 9). Over the consumption of eight 15 mL sips of ONS, individuals rated their sensory perception and subjective appetite perception using line scales. Additionally, in-mouth aroma release was measured for each sip, using atmospheric pressure chemical ionisation (APCI). Compared with the MF and HF group, the LF group reported a significantly greater increase of mouth-drying over increased sips (p = 0.02). The LF group also experienced significantly higher aftertaste perception (p < 0.001), and more intense in-mouth aroma release (p = 0.015), compared with the HF group. These findings occurred concurrently with relatively lower hunger sensations in the LF and MF group. Many patients who are prescribed ONS likely experience reduced salivary flow rates. The unique sensory experiences of these individuals should be considered in order to optimise palatability and nutritional intake.

Sodium ion interaction with psyllium husk (Plantago sp.).

The nature of and factors effecting sodium interactions with psyllium were investigated in vitro. In a batch extraction system, psyllium mucilage gel retained at least 50% of sodium across a range of concentrations (5-300 mg sodium per g psyllium) and pH (2-10) environments. FTIR and Na NMR analyses of psyllium gels indicated that binding was complex with non-specific multi-site interactions. The potential use of psyllium husk as a binding agent for the reduction of bioavailable sodium was therefore evaluated. The binding of sodium at physiologically relevant conditions (pH 1.2 (stomach) and 6.8 (intestine)) was studied in a gastrointestinal tract (GIT) pH simulated model. Results show consistently high sodium retention (∼50%) across the GIT model and less than 20% loss of bound sodium under the simulated intestinal pH conditions after repeated washings.

Impact of nitrogen flushing and oil choice on the progression of lipid oxidation in unwashed fried sliced potato crisps.

Unwashed, sliced, batch-fried potato crisps have a unique texture and are growing in popularity in the UK/EU premium snack food market. In this study, the storage stability of unwashed sliced (high surface starch) potatoes (crisps) fried in regular sunflower oil (SO) or in high oleic sunflower oil (HOSO) was compared over accelerated shelf life testing (45°C, 6 weeks); with and without nitrogen gas flushing. Primary oxidation products (lipid hydroperoxides) were measured with a ferrous oxidation-xylenol orange (FOX) assay and volatile secondary oxidation products (hexanal) were quantified by using solid phase micro-extraction gas chromatography mass spectrometry (HS-SPME-GC/MS). Results revealed that crisps fried in SO were the least stable. Flushing the stored crisps with nitrogen gas proved to be effective in slowing down the oxidation rate after frying with sunflower oil, significantly stabilizing the crisps. However, crisps fried in HOSO were the most stable, with the lowest rate of development of oxidation markers, and this has previously not been shown for crisps with a high free starch content.