Effect of Fruit and Vegetable Consumption on Immune Function in the Elderly

Study Overview
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Brief Summary
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The immune system undergoes a range of changes as individuals become elderly. These may manifest as an increasing susceptibility to infection or a tendency to develop autoimmune or malignant disease. Multiple underlying factors contribute to this phenomenon of immunological aging, and in this study the investigators will examine the possibility that inadequate diet may be one such contributing factor. Fruit and vegetable intake, which can be low in the elderly, is associated with reduced chronic disease risk. This proposal will test the hypothesis that increased fruit and vegetable intake may positively affect clinically relevant measures of immune function. One hundred healthy volunteers aged 65-85 years following a low fruit and vegetable diet (<=2 portions/d) will be recruited and randomised to continue following their normal diet, or to consume at least 5 portions of fruit and vegetables daily for 16 weeks. Immune function and biochemical markers of nutritional status will be assessed before and after the intervention period.

Official Title
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Effect of Fruit and Vegetable Consumption on Immune Function in the Elderly: a Randomised Controlled Trial

Conditions
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Immune Function

Intervention / Treatment
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* Behavioral: 5 portions
* Behavioral: 2 portions


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 65-85 years Habitual consumption of fruit and vegetables <= 2 portions daily Exclusion Criteria: Those on special diets, taking nutritional supplements or medications known to affect immune function or absorption of nutrients Excessive alcohol consumption (>28 U/week men or >21 U/week women) BMI>35 kg/m2 History of diabetes or dementia Pneumovax II vaccination within previous 2 years Inability to provide informed consent Any other problem which would prevent adherence to a high fruit and vegetable diet Recent infection (<3 weeks since completion of any antibiotic course or symptoms of viral illness)

Ages Eligible for Study
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Minimum Age: 65 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1<br>5 portions fruit and vegetables/day | Behavioral: 5 portions<br>* Subjects randomised to the intervention group will be provided with a selection of fruit and vegetables once a week (from a local supermarket) and will be asked to consume 5 portions of fruit and vegetables per day. For the purposes of this study, a portion will be as defined by the Food Standards Agency, i.e. an 80 g serving (one apple, orange or banana, or 3 heaped tablespoons of vegetables).<br>|
| Other: 2<br>2 portions fruit and vegetables/day | Behavioral: 2 portions<br>* Subjects randomised to the control group will be provided with a selection of fruit and vegetables once a week (from a local supermarket) and will be asked to consume 2 portions of fruit and vegetables per day. For the purposes of this study, a portion will be as defined by the Food Standards Agency, i.e. an 80 g serving (one apple, orange or banana, or 3 heaped tablespoons of vegetables).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in natural killer cell cytotoxicity and antibody response to Tetanus toxoid and Pneumovax II vaccination |  | 16 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in other markers of immune function |  | 16 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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IgG subclasses, Natural killer cell cytotoxicity, Antibody response, Tetanus toxoid vaccination, Pneumovax II vaccination, Total serum immunoglobulins