Age-related olfactory and taste changes and interrelationships between taste and nutrition

Effect of dietary supplements and physical exercise on sensory perception, appetite, dietary intake and body weight in frail elderly subjects

This present study investigated the effect of a 17-week intervention programme with nutrient-dense foods (enriched with vitamins and minerals at 25-100% of the Dutch recommended dietary allowance) and/or physical exercise in 159 frail elderly subjects (forty-six men, 113 women, mean age 78.7 (SD 5.6) years). Subjects were randomized into four groups: (1) control, (2) nutrition intervention, (3) exercise or (4) both nutrition intervention and exercise. Main outcome variables were sensory perception (smell test and questionnaire), appetite (questionnaire), energy intake (3 d food record) and body weight (on a weighing scale and with dual energy X-ray absorptiometry measurements). At baseline, moderate but significant correlations were found between appetite and energy intake (r 0.30, P < 0.0001), between smell test and smell perception assessed by questionnaire (r 0.40, P < 0.0001) and between lean body weight and energy intake (r 0.50, P < 0.0001). Results after 17-weeks intervention revealed neither change in smell test scores (P = 0.19) nor in appetite (P = 0.17). A slight positive effect of exercise compared with non-exercising groups on energy intake (difference 0.5 MJ, P = 0.05) was shown next to a preserving effect of exercise on lean body mass (+0.08 kg) compared with a decrease (-0.4 kg) in non-exercisers (P < 0.02). The correlation between the change in lean body mass and change in energy intake was 0.18 (P = 0.05). In conclusion, an interesting preserving effect on lean body mass in frail elderly subjects due to 17 weeks of exercise was shown. Since a decline in lean body mass was observed in the non-exercisers, effects may be attributable to change in activity pattern. Changes in lean mass were also slightly, but significantly, correlated with changes in energy intake. In turn, energy intake was not related to a change in reported appetite or sensory perception. Nutrient-dense foods were not able to improve any of the outcome variables in this study.

Olfaction and psychiatry

Recent clinical studies have identified significant olfactory deficits in several neuropsychiatric disorders, notably Alzheimer's disease and Parkinson's disease. These have correlated with neurochemical and neuropathological studies of the olfactory system. The presence of a specific sensory deficit may be related to the localisation of pathology within the brain. There is a need for incorporation of olfactory testing into routine clinical examination.