Nutritional interventions in the anorexia of aging

Introduction

The drive to normal feeding characterizes healthy aging. This drive to feeding may change during the life span of human beings. In particular, near to the end of life in some elders, appetite and energy intake diminish and this may form a syndrome termed ‘the anorexia of aging’ (1). The diagnosis of this ‘senile’ anorexia can be made when, in absence of oral cavity impairments affecting normal/physiological feeding and/or chewing function, food intake reduction is equal to or higher than 50% of the served standard portion for three or more days (2).

Recently, in a national, multicentric study (funded by the Italian Ministry for the Research and the University - COFIN-MIUR 20050679) on the prevalence of senile anorexia in different settings, it has been found that the prevalence varies, attaining 33.3% in women and 26.7% in men in acute wards and rehabilitation settings, while only 8% in free-living subjects (2). The measured prevalence of senile anorexia found in this study is comparable with other epidemiological data (3).

A recent etiopathogenetic classification has been proposed, whereby the anorexia of aging can be categorized into: physiological (multiple levels alterations of food intake regulating system), pathological (occurring in presence of acute or chronic pathologies), related to environmental factors (income, cooking facilities, education, distance to food store, availability of transportation), or related to iatrogenic conditions (hospitalization, drugs side effects) (4). It often happens that multiple causes may coexist in determining the anorexia of aging and the real cause may be unacknowledged and/or underestimated.

The therapy of senile anorexia is likely to include multiple interventions following evaluation of all co-existing causes. However, in each class of senile anorexia the lowest common denominator is food intake reduction so that the basic treatment of senile anorexia should be focused to improve nutritional intake in order either to prevent or treat malnutrition and its related negative outcomes on clinical status. At the moment, no systematic review of the literature (according to a strict methodology and eventually followed by a meta-analysis) is available on this topic. Only “unstructured” reviews of literature exist and this may be due to the fact that past researches had been planned to seek intervention procedures able to treat malnutrition (either energy or protein or protein-energy malnutrition), a consequence of senile anorexia, rather than senile anorexia itself.

An attempt to identify current treatments for reduced nutritional intake and its related factors was recently performed (5). Authors identified different nutritional interventions to increase the nutritional intake in older adults, according to the presence of factors influencing the reduced nutritional intake:

• -personal factors (physiological changes, social changes, psychological changes, eating process): oral nutritional supplements (in particular small liquid formula, containing all necessary nutrients, being less satiating and having only a short-term satiety effect) are suitable
• -food factors (ingredients (high protein, high fibre, slow-digestible, carbohydrates), food attributes (high viscosity, large volume), monotonous diet, culturally inappropriate food, presentation of too large portion size]: between-meal snacks with high energy density (either provided as small liquid formula or solid reduced volume meals) are appropriate
• -environmental factors (living alone, social isolation, meal interrupting procedures, lack of help with eating, inappropriate mealtimes): ambience modification (eating with familiar others, motivation, encouragement and help by carers, pleasant eating environment) are opportune.

In addition, the same authors tried to identify evidence of the efficacy of different current practices to improve nutritional intake by elders:

• 1.dietary advice: may improve energy and potentially protein intakes but there is a lack of sufficient supporting clinical data
• 2.meal fortification: may ameliorate energy (14-26%) and protein (0-23%) intake according to the setting in case of nutrient and energy intake often are below recommended levels with possibly resulting in elevated saturated fat intake
• 3.variety of diets: no strong data available, but it may stimulate energy intake and help to maintain nutritional balance
• 4.between-meal snacks and frequent meals: increased overall nutritional intake either in energy (≈ 600 kcal/day) or in protein (≈ 16 g/day)
• 5.oral nutritional supplements: significantly increase of nutritional, protein (≈ 14 g/day) and energy (≈ 415 kcal/day) intake and improvement of clinical outcomes.

Furthermore, factors promoting nutritional intake have also been enlisted for each category. For example, among personal factors promoting nutritional intake good health and motivation to eat are important. Other environmental factors promoting nutritional intake are: distraction (i.e. watching TV), convenience/easy access to food, encouragement by care givers, sharing meal with other people/ambience, eating at the same time every day.

Treatments for the anorexia of aging can be classified into:

• 1.
  Interventions relating to foodstuffs

  • a.
    food flavour and taste enhancement of cooked and non-cooked meals (6, 7, 8)
  • b.
    energy-protein enriched food/meal/snacks (9, 10)
  • c.
    high dietary variety (11)
• 2.
  Feeding interventions

  • a.
    feeding assistance by high trained staff (12)
  • b.
    additional evening hot meal (13)
• 3.
  Subject/patient interventions

  • a.
    appetite enhancers (dronabinol, megestrol acetate) (14, 15, 16)
  • b.
    antidepressant (serotoninergic or non-serotoninergic) (17)
  • c.
    oral nutritional supplements or commercially available supplements (18)
  • d.
    exercise and multinutrient supplementation (19)
  • e.
    supplementation with polyunsatured fatty acids and vitamin E (20)

Adding flavour to food (choosing between: chicken, beef, bouillon, turkey, lemon, butter, fish flavour in relation to the nature of protein rich meal component and the cooking process) and enhancing taste of cooked or non-cooked meals (food flavour amplification of skimmed-milk and Quorn ® (meat substitute based on Fusarium graminearum) significantly increases body weight (6, 7, 8).

The energy-protein enriched food/meal furnished by enriching a standard hospital menu in particular with cream, butter, mono- and polyunsatured oils, protein powder, increases daily energy (lunch and supper), protein, fat, carbohydrates, vitamins and minerals (except for iron) intake (9, 10), while a highly varied diet in elderly nursing home residents is only associated with better nutritional status (11).

A very effective, but unfortunately expensive, feeding intervention to improve nutritional (either food or fluid) intake is providing optimal feeding assistance by high trained staff by: one-to-one and continuous assistance, standardized graduated prompting protocol enhancing self-feeding administration, social interaction during meal-time, supporting subjects’ preferences for dining location and type of assistance, proper positioning of the subject for eating, meal substitution if requested by subjects, extended access to tray up to 1.5 hours per meal (12).

The additional evening hot meal (i.e. mushroom soup or sandwich with ham and cheese or pancake with jam and whipped cream) significantly improves medium-term (6 months) nutritional status, mean energy, protein, carbohydrates intake (13).

Finally, considering subject interventions, in the elderly the use of orexigenic drugs to treat weight loss has been banned by the U.S. Food and Drug Administration since 2002 (14). The use of oral Megestrol Acetate (at dose of 400 mg/daily in the morning) in addition to optimal care feeding and Dronabinol (at dose of 2.5 mg twice daily 30 minutes before lunch and dinner) determined respectively: significant increase of foods and fluids intake and body weight, at weeks 4-6 (in the control group, without optimal feeding assistance, those parameters did not increase) (15) and small, not significant increase in body weight (16).

Antidepressants, either serotoninergic or non-serotoninergic, significantly seems to increase body weight, to ameliorate appetite and to improve the MNA score (17).

Various studies of oral nutritional supplements show that supplementation leads to a small but consistent weight gain, may reduce mortality in older people who are undernourished and induces a beneficial effect on related complications; however, it does not improve functional status or reduce length of hospital stay (18).

Also the administration of exercise and multinutrient supplementation in particular, high-intensity, progressive regimen of resistance exercise of the hip and knee extensor for 3 days per week for 10 weeks training ameliorates muscle strength and size in frail elderly subjects while the oral liquid supplement (@ 360 kcal/daily, 60% of carbohydrates, 23% of fat and 17% of protein) has neither an independent nor an additive effect on muscle strength and size, despite a marginal nutritional intake at the baseline (19).

In a study of elderly cancer patients supplementation with fish oil (18 g of omega-3 polyunsaturated fatty acids, PUFA) plus vitamin E (200mg daily) led to a significant decrease in both the absolute numbers and percentages of total T cells and helper T cells, no significant effect on food intake, body weight, serum albumin or transferrin, and a significant increase of Karnofsky performance index (20).

It appears that there is a lack of randomized studies in which a detailed definition of the anorexia of aging has been made. These studies are also characterised by a lack of homogeneity of tools to evaluate the nutritional status and, in particular, by a lack of multidimensional evaluation of the factors related to reduced food intake, by a paucity of the sample, a high rate of attrition (without any drop-out analysis) and a short time of observation.

Last but not least, in all studies the intervention aimed at increasing food intake is not targeted to the cause of anorexia. In the study performed by our group it was found that all subjects with anorexia received a very intense assistance, but this assistance was almost always standardised with the use of low-consistency foods and oral supplements. As a consequence, a greater milk intake was related to a worst nutritional status (data not published).

Within clinical gerontology it is widely recognized that undertreatment may adversely affect long-term outcomes especially in frail elders. Hence we need to foster a culture of increased efforts in research that optimizes existing treatments and discovers new treatment strategies for the anorexia of aging.