Effect of flavor enhancers on the nutritional status of older persons

Abstract

Objectives

This study on flavor enhancers aims to: 1) compare food intake of older persons, 2) determine changes in body weight, blood pressure and serum sodium and 3) determine tolerance/intolerance to the flavor enhancers.

Design

The project is a cross-over, double blind study design.

Setting

A nursing home for the aged, Golden Acres Institution located in Quezon City, Philippines.

Participants

Sixty eligible subjects (31 males and 29 females), aged 60 years and over.

Intervention

Subjects were initially given: pouch A (0.5gram monosodium glutamate) or pouch B (0.5gram iodized salt) for lunch and supper for 2 months. The intervention was switched after one week wash period.

Measurements

Before the start and during intervention, 24 hour food intake of subjects was recorded and anthropometric and clinical data were measured. Tolerance/intolerance to the flavor enhancer and data on the quality of life were evaluated using a pre-tested structured questionnaire. Paired t-test was used to determine significant changes among each period of dietary intervention between different groups.

Results

Energy intake and almost all nutrients increased for males and females for both interventions. Body weight and body mass index increased significantly for both gender with MSG usage but not with iodized salt. The diastolic blood pressure of all subjects was normal while the systolic blood pressure remained at pre-hypertension level before and after both interventions. The sodium serum was within normal levels for both groups for both interventions. It was also observed that systolic blood pressure increased in both groups while sodium levels did not. It was further observed that both MSG and iodized salt interventions were well tolerated by majority of the participants.

Conclusion

The use of flavor enhancers have increased food intake and were well-tolerated among older persons. No difference in blood pressure and sodium serum was noted in both MSG and iodized salt intake.

Recommendation

People with less appetite, especially among older persons can use flavor enhancers to improve their food intake and body weight. Sodium containing flavor enhancers can be part of a healthy diet for older persons when used in moderation.

Introduction

People at age 60 and over generally have diminishing taste and smell. This condition can lead to inadequate intake of food which may result to poor nutritional status of older persons.

To address the problem of poor food intake on older people, monosodium glutamate (MSG), a common flavor enhancer in the Philippines, will be tried to confirm its effect on their food intake. To avoid bias, iodized salt was used as another flavor enhancer.

The study aims to: 1) compare food intake, 2) determine changes in body weight, blood pressure and serum sodium and 3) determine tolerance/intolerance. Tolerance is defined as the participant’s perception on the food being served: its palatability and if it can increase one’s appetite or cause food allergy among others.

Methodology

Research Design

The project is a cross-over, double-blind, non-randomized study design.

Research Site

The research site for the study was Golden Acres Institution, a nursing home for the aged of the Department of Social Welfare and Development (DSWD), Philippines (1).

Participants

Three cottages (2 for males and 1 for female) having the most number of possible participants were selected based on the inclusion/exclusion criteria such as: mental and physical fitness based on the examination of a medical doctor; ability to feed oneself; ambulatory condition; negative history of significant illness (e.g. malignancy of any type or kidney malfunction); negative major surgical operation; negative gastrointestinal bleeding; negative cardiovascular disease; negative low salt diet as advised by a physician and negative food allergy. Sixty seven (67) participants, (36 males and 31 females) were selected.

Data collection

Anthropometric measurements were done among participants using standard techniques.

Clinical data like blood pressure and serum sodium were noted. The reference by the Joint National Committee on Detection, Evaluation and Treatment of High Blood Pressure (JNC VII) was used in classifying blood pressure obtained, where < 120 systolic BP/80 diastolic BP is normal, 120-139/80-89 is pre-hypertension and ≥ 140/90 and above is hypertension category (2).

Serum sodium was collected and analyzed by a reputable laboratory outside FNRI. The normal value for serum sodium is 137 - 145 millimoles per liter (3).

The 24 hour food intake of participants without flavor enhancers was monitored at baseline. After baseline, the 2 groups (male and female) ate their usual food intake for the day with added pouch A (containing 0.5g MSG) or pouch B (containing 0.5g iodized salt) for lunch and supper. The 24 hour food intake was monitored for 3 weekdays and 1 weekend per week for 2 months by the researchers. After 2 months, a one-week wash period was observed, then, another baseline data was taken, and then a cross-over ensued for 2 months. Days with donated lunch or supper were not considered in the monitoring of food intake. For days that researchers were not present in the area, houseparents gave the flavor enhancer to participants.

In determining the amount of food eaten by participants, calibrated cups and weights of sample food were used. For individually wrapped snack foods, the weight stated on the food package was used. Food recall by participants or the assigned houseparents was done to elicit food intake when researchers were not present.

The participants were interviewed using a pre-tested questionnaire to elicit their perception on tolerance/intolerance for the 2 pouches: A (MSG) and B (iodized salt).

Data Analysis

To compute nutrient values, The FNRI Food Composition Tables (FCT) computer software and the food labels, particularly for iron and vitamin A for fortified foods were used.

Descriptive statistics using SPSS software was used to describe the characteristics of the respondents and paired t-test was also used to determine significant differences between different groups.

Results

Participants

There were 67 participants (36 male and 31 females) at baseline but due to drop-outs, participants became 60 (31 males and 29 females). Drop-outs were attributed to transfer to other cottages and provincial institutions or discharged.

The mean age of participants was 73 years old (y/o): 72 y/o for males and 75 y/o for females. Most of the participants were single (58.3% male and 41.9% for female). Majority of the participants reached elementary level (44.4% male and 64.5% female).

Effect of MSG and iodized salt

Dietary Intake

Results showed that male participants when given MSG had significantly increased intake for energy and nutrients like fat and carbohydrate compared to no intervention done at baseline. On the other hand, food intake with added salt had also significantly increased for energy and carbohydrate.

Among male participants, there was a significant increase for protein during MSG intervention while there was higher increase for carbohydrate obtained after iodized salt intervention. The greater the negative values on mean difference suggest higher intakes.

The female participants, when given iodized salt had significant increase intake of energy and nutrients like fat and carbohydrate compared to baseline. Likewise, after they were given MSG, there was significant increase on energy and carbohydrate.

Weight and Serum Sodium

Data also revealed that mean body weight of participants increased significantly for both genders with MSG usage but not with iodized salt.

The serum sodium of all participants was within the normal serum sodium of 137 - 145 mmol/L. for both genders for both interventions. Though, those with salt intervention had higher values at endline compared to those with MSG intervention.

Blood Pressure

The mean systolic blood pressure of participants remained at pre-hypertension level and diastolic blood pressure at normal level at both baseline and endline using both interventions for both genders as shown in table 2. Systolic blood pressure increased in both groups while sodium levels did not.

Table 1.

Mean weight, serum sodium of male and female elderly across intervention periods

Gender		1st Intervention			2nd Intervention
	Baseline	End line	Mean difference; (C.I.)	Baseline	End line	Mean difference; (C.I.)
Male		MSG			Iodized salt
weight (kg) serum Na (mmol/L)	50.9 ± 6.8 142.3 ± 3.26	52.6 ± 6.8 139.5 ± 1.86	−1.71*** (−2.66 to -0.76) 3.05*** (1.86 to 4.25)	53.1 ± 6.4 142.3 ± 3.26	52.6 ± 7.6 139.6 ± 2.60	0.46ns(0.33 to 0.20) 2.68*** (1.70 to 3.66)
Female		Iodized salt			MSG
weight (kg) serum Na (mmol/L)	43.6 ± 11.4 144.2 ± 2.52	44.0 ± 11.0 139.0 ± 2.62	−0.32ns (−1.40 to 0.75) 5.56*** (4.47 to 6.10)	42.7 ± 9.7 144.2 ± 2.52	43.9 ± 9.3 138.7 ± 2.12	−1.25*** (−2.14 to -0.36) 5.28*** (4.49 to 6.64)
95% CI - 95% Confidence Interval		*** – significant at < 0.01		ns – not significant

Table 2.

Mean blood pressure (mmHg) of male and female elderly during intervention period

Gender		1st Intervention		2nd Intervention
	Baseline	Endline	Baseline	Endline
	SP	DP	SP DP	SP	DP	SP DP
Male			MSG			Iodized salt
MBP (mmHg)	120	76	128*** 74ns	127	76	130*** 74ns
Female			Iodized salt			MSG
MBP (mmHg)	122	75	129* 75”	122	72	133*** 77ns
Legend: SP-Systolic Pressure, BP-Diastolic				Blood pressure classification:
	Normal - <120/80
ns – not significant	Pre-hypertension - 120 -139 / 80-89
* – significant at < 0.05	Hypertension - 140 / 90 and above

Tolerance

Almost all participants said the food was delicious and had not gotten sick during the two intervention periods, suggesting that MSG and iodized salt were well tolerated. As to the perception of liking to have more food, participants said that the food served to them were just in the right amount to make them full.

Discussion

The study showed positive results on the use of flavor enhancers in increasing food intake of older persons in institutions. Result of the study is consistent with the results of other studies (4., 5., 6., 7.) that used monosodium glutamate (MSG) in increasing food intake in older persons. The addition of MSG enhanced the palatability of foods of the European diet, increased food intake of elderly in hospital setting and among cancer patients. For diabetic patients, the addition of MSG to experimental foods consisting of soup and vegetable resulted to a preferred intake of the test foods over that of dessert which could improve nutritional status of diabetics. The sodium content can be decreased with the addition of MSG to soups, without altering palatability, favoring a net decrease in sodium intake (8).

In this study, the body weight of participants increased significantly for both genders with MSG usage but not with iodized salt. The same was also observed with the study by Mathey (2001) on 67 elderly nursing home residents (9. While not significant, a trend towards decreasing weight (among males) was evident in the second intervention. This could be due to more active physical activity during this period of the Christmas season wherein more socialization activities were done. Thus, differences in result for weight could be due to differences in physical activity. Males appear to be more active than females.

Blood pressure results showed that the blood pressure of participants remained in the pre-hypertension category after MSG and iodized salt intervention. It appears that the amount of MSG and iodized salt the elderly received were not much to cause hypertension. The study by Prawirohardjono, et. al done among 52 Indonesians aged 18 to 65 year old revealed that there was no significant difference in blood pressure among study participants treated with encapsulated MSG of 1.5 or 3g or from placebo (10). The purpose of encapsulating MSG was to minimize MSG taste and subject bias.

The result of the study on serum sodium was in consonant with blood pressure result where the total mean sodium intake of participants did not exceed the normal serum sodium level of 137 - 145mmol/L. This indicates that the amount of flavor enhancers added to the food of older persons were within normal level.

Conclusion

The use of flavor enhancers increased food intake and was found to be well tolerated by older persons. Weight increased for both males and females after MSG but not after iodized salt. No difference in blood pressure and serum sodium was noted in both MSG and iodized salt intake.

Recommendations

People with less appetite, especially among older persons can use flavor enhancers to improve their food intake and body weight. Sodium containing flavor enhancers can be a part of a healthy diet for older persons when used in moderation.