Study on How the Form of Food Physically and Mentally Affects the Elderly

―Analysis of Autonomic Nervous Reaction and Subjective Evaluation―

Abstract

Purpose:　To study how food forms physically and mentally affect the elderly from the analysis of the elders' autonomic nervous system reactions (changes to the systolic blood pressure, pulse, and salivary amylase) and subjective evaluation.

Subjects:　18 elderly adults (6 males and 12 females) living at home in Area A, with an average age of 69.11 (with 4.5 years on either side).

Method:　In a quasi-experimental cross-over design, two food forms, solid bananas and mashed bananas, were used. The ANOVA procedure was taken for analysis of changes in the autonomic nervous system that occurred before and after the intake of the food in both forms, and the Wilcoxon signed-rank test was used for subjective evaluation.

Results and Discussion:　The main effect was seen in the autonomic nervous system reactions that occurred before and after the intake of the food, and the values of the elders’ systolic blood pressure, pulse, and salivary amylase significantly lowered after the intake of the food in both forms (p＜0.01). No interaction by the form of the food or by the order of forms of food to be taken was observed. The decline in autonomic nervous system activities after the intake of food, regardless of its form, can be considered as a result of a sense of comfort given by the action of eating. Subjective evaluation was conducted from the five points of appearance, smell, taste, temperature, and texture (p＜0.05). As a result, the mashed banana was given significantly lower evaluations than the solid bananas on all the five points. The subjects knew they were the same food but still preferred solid bananas to mashed ones. It was therefore concluded that the mental promotion of appetite can be affected by the form of food.

Conclusion:　The autonomic nervous system activities of the elderly individuals declined regardless of the form of the food, while in the subjective evaluation, mashed bananas were poorly evaluated as the individuals preferred taking solid bananas. It can be said that the taste and form of food are connected in the memory of individuals, and that the appetite may be lost when the actual taste and form disagree. Due to dysfunction or other disorders, elderly patients are often forced to eat food in a form that they have never experienced before. It is however important to encourage elderly patients to have a healthy appetite for food. This study suggests the importance of keeping the form of the food that promotes the appetite of elderly patients.