Zoe S. Warwick

Effect of flavor enhancement of foods for the elderly on nutritional status: Food intake, biochemical indices, and anthropometric measures

The irreversible declines in taste and smell acuity that occur in many elderly persons can contribute to inadequate food intake and nutrition that are prevalent among the aged. Although chemosensory deficits cannot be reversed, previous studies have shown that the addition of intense flavors to foods can compensate for perceptual losses and improve food palatability and acceptance. In this study, the effect of sustained (3 week) flavor enhancement of typical institutional foods on the diet, health, and well being of 39 elderly (average age 84.6 SE 0.81 years) retirement-home residents was evaluated. For 3 weeks subjects ate an institutional diet (unenhanced). During another 3-week period, the same subjects ate identical foods to which intense flavors were added (enhanced). The 39 subjects were tested in two groups. For group 1 the unenhanced food period preceded the enhanced food period. For group 2, the order was reversed. Food intake was measured every weekday throughout the study, and the nutritional composition of the diet was analyzed. Biochemical measures of health status were obtained at the beginning of the study (baseline) and following both the unenhanced and enhanced periods. These measures included somatomedin-C/insulin-like growth factor I, transferrin, total T- and B-lymphocytes, and routine blood chemistries. Weight, height, midarm circumference, and triceps skinfold thickness were also measured. Handgrip strength and pinch strength were measured in group 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Bitterness of sweeteners as a function of concentration

Sixteen trained tasters provided sweetness and bitterness intensity ratings for 19 compounds including: acesulfame-K, alitame, aspartame, fructose, glucose, glycine, lactitol, maltitol, monoammonium glycyrrhizinate, neohesperidin dihydrochalcone, neosugar (fructo-oligosaccharide), palatinit (isomalt), rebaudioside-A, sodium cyclamate, sodium saccharin, stevioside, sucralose, sucrose, and thaumatin. With increasing concentration, high-potency sweeteners including acesulfame-K, neohesperidin dihydrochalcone, sodium saccharin, rebaudioside-A, and stevioside tended to become more bitter. Low-potency sweeteners including fructose, sucrose, and lactitol tended to become less bitter with increasing concentration.

Aspartame and susceptibility to headache.

We performed a double-blind crossover trial of challenges with 30 mg of aspartame per kilogram of body weight or placebo in 40 subjects who reported having headaches repeatedly after consuming products containing aspartame. The incidence rate of headache after aspartame (35 percent) was not significantly different from that after placebo (45 percent) (P less than 0.50). No serious reactions were observed, and the incidence of symptoms other than headache following aspartame was also equivalent to that after placebo. No treatment-related effects were detected in vital signs, blood pressure, or plasma concentrations of cortisol, insulin, glucagon, histamine, epinephrine, or norepinephrine. Most of the subjects were well educated and overweight and had a family or personal history of allergic reactions. The subjects who had headaches had lower plasma concentrations of norepinephrine (P less than 0.0002) and epinephrine (P less than 0.02) just before the development of headache. We conclude that in this population, aspartame is no more likely to produce headache than placebo.

Taste and smell sensations enhance the satiating effect of both a high-carbohydrate and a high-fat meal in humans

The effects of meal sensory properties (tasty vs. bland) and nutrient composition [high-CHO (carbohydrate) vs. high-FAT] on hunger ratings, blood glucose and free fatty acids (FFA), taste perception, and subsequent food intake, were studied in human subjects. Aspartame and vanilla were used to augment meal palatability, yielding four isocaloric liquid meals: bland-FAT, tasty-FAT, bland-CHO, tasty-CHO. Normal-weight, nondieting young adults consumed each of the meals for breakfast on separate days. The main finding was that tasty versions of high-FAT and high-CHO meals were more satiating than nutritionally identical bland meals, as indicated by a greater decrease in hunger ratings following the tasty meals. Changes in blood glucose and FFA were related to meal nutrient composition, but not to meal sensory properties. High-CHO meals tended to be more satiating than high-FAT meals. Consumption of each of the meals produced a similar decrease in pleasantness ratings of food-related tastes. Intake of carbohydrates was significantly higher at a self-selected lunch 5.25 h following a tasty breakfast. These findings indicate that hunger is decreased to a greater extent by meals flavored with aspartame and vanilla relative to nutritionally identical, unflavored meals. The satiety-enhancing effect of oral stimulation was found for both high-FAT and high-CHO meals.

Flavor enhancement of foods for the elderly can reverse anorexia

Impairment of the senses of taste and smell is one of the major factors contributing to anorexia in the elderly. Anorexia often remits when foods are amplified by additional odor to compensate for diminished chemosensory functioning.

Gustatory and olfactory dysfunction in dementia: Not specific to Alzheimer's disease

Significant losses in the ability to detect the taste of glutamic acid and to recognize odorants were found in demented patients when compared with age-matched controls. These losses were not specific to patients with Alzheimers disease (AD) but were also found in demented patients without AD. Detection thresholds for bitter-tasting quinine HCl were not higher in demented patients than in age-matched controls but were higher than thresholds in young subjects. These data suggest that losses in taste in demented patients may vary with the chemical structure of the tastant. The degree of loss in the ability to recognize odorants was greater in patients with a family history of senile dementia.

Dissociation of palatability and calorie effects in learned flavor preferences.

Rats acquire a preference for a flavor paired with a caloric solution over a flavor paired with a solution providing fewer or no calories. Because the palatability and the caloric value of the solutions typically covary, it is unclear which property of the high-calorie solution reinforces the flavor preference. Two studies were conducted to assess the independent effects of palatability and calories in flavor preference conditioning. In Experiment 1, rats consumed two distinctively flavored solutions having equal palatability but different caloric value. The flavor paired with ingestion of more calories was subsequently preferred, indicating that a caloric advantage is sufficient to establish a flavor preference (flavor-calorie conditioning). In Experiment 2, rats consumed two distinctively flavored solutions having equal calories but different palatability. The flavor paired with the more palatable solution was subsequently preferred, indicating that a palatability advantage is sufficient to establish a flavor preference (flavor-flavor conditioning). This finding demonstrates flavor-flavor conditioning in the context of postingestive stimulation by calories. Taken together, these results demonstrate both flavor-calorie and flavor-flavor conditioning in the context of normal ingestion (i.e., self-paced oral intake of nutritive solutions).

Use of Flavor‐Amplified Foods to Improve Nutritional Status in Elderly Persons

Impairment of taste and smell perception can lead to decreased food intake in the elderly. The losses in chemosensory functioning can result from normal aging, disease state, drugs, and environmental pollutants. Experimental investigations are underway to develop practical taste enhancers. Clinical studies suggest that the addition of odors to foods to compensate for diminished chemosensory functioning is often helpful in increasing intake of nutrient-dense foods in older persons.

Independent effects of diet palatability and fat content on bout size and daily intake in rats

Although considerable evidence attests to the hyperphagic effects of high-fat (HF) diets, the attribute(s) of these diets (e.g., palatability, caloric density, and postingestive effects) which promote overeating is still unclear. The present studies investigated the independent effects of diet palatability and macronutrient composition on intake using the self-regulated intragastric infusion paradigm. In Experiment 1, rats were infused with either HF or high-carbohydrate (HC) diet while drinking either saccharin (Sacc) or a more palatable saccharin-glucose (SaccGlu) test solution for 9 days. HF elicited greater daily intake than HC; lick pattern analysis revealed that HF produced larger but not more frequent bouts. Test solution was not related to intake, possibly due to the relatively modest palatability manipulation. Experiment 2 provided a more sensitive test: The palatability manipulation was strengthened and diet infusion made optional by provision of chow. HF again elicited larger bout size and total daily intake (diet+chow) than HC. Rats given the more palatable solution significantly increased intake (via larger bouts) and thus the amount of diet infused, but chow intake decreased such that total kilocalorie intake was not significantly related to solution palatability. The reliable observation that HF promoted larger bout size and greater total kilocalorie intake than HC provides additional evidence that fat sends weaker feedback signals relevant to controls of both satiation (suppression of ongoing eating, behaviorally manifest in meal size) and satiety (suppression of subsequent intake, reflected in total daily intake).

Effect of food deprivation and maintenance diet composition on fat preference and acceptance in rats.

High-fat diets typically elicit greater kcal intake and/or weight gain than low-fat diets. Palatability, caloric density, and the unique postingestive effects of fat have each been shown to contribute to high-fat diet hyperphagia. Because long-term intake reflects the sum of many individual eating episodes (meals), it is important to investigate factors that may modulate fat intake at a meal. The present studies used high-fat (hi-fat) and high-carbohydrate (hi-carb) liquid diets (both 2.3 kcal/mL) to assess the effect of hunger level (0 versus 24-h food deprivation) and fat content of the maintenance diet (12 versus 48%) on fat preference (when a choice among foods is offered in a two-bottle test), and acceptance (only one food offered) in male rats. Preference for hi-fat relative to hi-carb (two-bottle test) was enhanced by 24-h food deprivation, and by a high-fat maintenance diet. In contrast, neither deprivation nor maintenance diet composition influenced relative meal size (one-bottle test) of hi-fat and hi-carb: irrespective of test conditions, meal size of hi-fat was bigger than meal size of hi-carb.