Olfactory and gustatory functioning and food preferences of patients with Alzheimer\u2019s disease and mild cognitive impairment compared to controls: the NUDAD project

A S Doorduijn,J L P Fieldhouse,O Van De Rest,M Visser,P Scheltens,M I Kester,F A De Leeuw,S Boesveldt,C E Teunissen,M A E De Van Der Schueren,W M Van Der Flier

doi:10.1007/s00415-019-09561-0

Abstract

Our aim is to compare olfactory and gustatory function and food preferences of patients with Mild Cognitive Impairment (MCI) and Alzheimer’s disease (AD) with controls. We included 22 patients with MCI, 30 patients with AD and 40 controls and assessed olfactory threshold, odor discrimination and odor identification (Sniffin’ Sticks), gustatory functioning (Taste Strips), and food preferences (Macronutrient and Taste Preference Ranking Task). Linear regression analyses were used to study associations of five cognitive domains or AD biomarkers with olfactory functioning. Groups did not differ in olfactory threshold, gustatory function and food preferences. Patients with MCI and AD scored lower on odor discrimination and identification than controls. Poorer memory, but no other cognitive domain, was associated with poorer odor discrimination and odor identification, but not with odor threshold. No associations with AD biomarkers were found. In conclusion, patients with MCI and AD have poorer odor discrimination and identification ability than controls, but similar detection thresholds. This is likely a consequence of poorer memory rather than directly caused by AD pathology.

Highlights

Unintended weight loss and malnutrition are common features in patients with Mild Cognitive Impairment (MCI) and Alzheimer’s disease (AD) dementia, with prevalence rates ranging from 0–60% [1,2,3,4]
Patients with MCI and AD dementia were older and had a lower Mini-Mental State Examination (MMSE) score compared to controls, and patients with AD dementia were lower educated than patients with MCI and controls (Table 1)
Patients with MCI and AD dementia scored lower on odor discrimination and identification compared to controls (9.0 and 9.5 vs. 11.6; 9.5 and 9.2 vs. 11.6, respectively) (Fig. 1)

Summary

Introduction

Unintended weight loss and malnutrition are common features in patients with Mild Cognitive Impairment (MCI) and Alzheimer’s disease (AD) dementia, with prevalence rates ranging from 0–60% [1,2,3,4]. It is unknown whether this weight loss is due to a higher energy expenditure, reduced dietary intake, a combination of both, or that it is influenced by other factors. Dietary intake is partly driven by olfactory and gustatory functioning and food preferences [5]. Poor olfactory function is associated with higher mortality in older adults [11]

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