The Effect of Consumption of Kiwifruit on Constipation in Adults
Condition: Constipation
MeSH terms: Constipation
Study type: Interventional

Summary: 
      Constipation is a symptom suffered by a large number of people, due to multifactorial causes.
      Some studies have proven that modifying lifestyle reduces the risk of constipation, with
      high-fibre diets being less prone to constipation. Kiwifruit consumption, improves functional
      constipation and some studies consistently report an increase in the frequency and ease of
      defecation, stool volume and softness.

      Although literature suggests kiwifruit consumption improves constipation symptoms, no studies
      have been carried out in adults and in Mediterranean patient populations, characteristic for
      its differential nutritional habits. The aim of the present study was to test the effect of
      kiwifruit consumption on functional constipation in a Spanish adult population.
    

Detailed description: 
      Worldwide general population prevalence of constipation ranges from 0.7% to 79% (median 16%).
      Some factors associated with constipation are sex, with higher prevalence in females
      (especially during pregnancy, and age; in general it becomes gradually more prevalent after
      the 70 years of age, in women the increase is considerable from a young age (18-23 years old)
      to middle age (45-50 years old).

      Constipation is characterized by difficult or infrequent deposition, often accompanied by
      excessive straining during bowel movement or sensation of incomplete evacuation. In most
      cases, there is no underlying organic cause, and constipation is labelled as chronic
      idiopathic constipation and as a functional digestive disorder. The Rome III criteria is a
      useful tool for the diagnosis of constipation that highlights the chronic nature of the
      disorder and the importance of symptoms beyond the infrequency of bowel movements.

      Understanding its causes, prevention, and treatment will help most people find constipation
      relief. An individual's medical history is very important in determining a constipation
      diagnosis. Primary healthcare professionals should enquire about dietary habits and
      lifestyle, pharmacological and toxic habits, complementary and alternative medicine,
      physiological bowel habits, use of laxatives and past disease history

      Aims:

      To test the effect of kiwifruit consumption on functional constipation in a Spanish adult
      population

      Methods:

      Design :Open non-controlled and non-randomized longitudinal study, of the effect of kiwifruit
      consumption in adult patients with diagnosed constipation

      Setting: The study was conducted in five primary healthcare centres in Barcelona, Catalonia,
      Spain.

      Period Study: Between April and August 2013

      Population: Fifteen participating Primary Care Professionals selected patients from the
      electronic medical records (e-HCAP) following inclusion and exclusion criteria. Each
      professional could include a maximum of 4 patients. Forty-six subjects were selected for the
      study

      Sample size: It was calculated to detect a change in the proportion of individuals with 3 or
      more defecations per week from 56% to 86% (evolution from an average of 3.2 to 4.4 -stable
      Standard Deviation (SD) of 1.3- in a normal distribution). Assuming a bilateral contrast for
      paired data, with a significance level of 0.05 and power of 0.8, a sample of 44 individuals
      was required (covering a 10% of dropout rate).

      Intervention: The duration of the study was five weeks. During the first two weeks no
      kiwifruit patients were asked to follow their normal diet. The next three weeks they were
      asked to consume three Zespri green kiwifruits (Actinidia deliciosa var Hayward) per day, one
      at each main meal (breakfast, lunch and dinner). Throughout the five-week study period the
      patient had to continue their normal eating habits and exercise regime.

      Tools and instructions: Primary Care Professionals asked patients to participate in the study
      and explained it to them. Patients who voluntarily agreed to participate signed the informed
      consent, accepting all study procedures. Each participant in the study attended three
      consultations: the first one before starting the study, the second one after two weeks and
      the third one after five weeks.

      To collect the information patients used a questionnaire designed for this purpose. His/her
      Primary Care Professional provided instructions on the recording of faecal characteristics.
      The French original version of the diary was translated into Spanish and Catalan. Patients
      chose their own language to respond. Professionals collected data from diaries in a Google
      Docs form.

      Patients were supplied kiwifruits in a heterogeneous manner. Some patients in the study
      bought the prescribed product. In other cases it was the professional who provided the
      kiwifruits. In one of the Primary Care Centres, the neighbourhood shopkeeper was the
      responsible for delivering the kiwifruits to the patients. Patients who bought their own
      Zespri kiwifruit were refunded.

      Statistical analysis: Demographics for patients were summarized calculating medians
      [InterQuartile Range (IQR)] for continuous variables and proportions for categorical
      variables. Categorical variables were compared from baseline (second week) to last week using
      the Bhapkar test. For some analyses, Facility and Volume categorical variables were treated
      as continuous in order to provide results easy to interpret and taking into account
      individuals' correlations; in these cases, one unit of gain should be interpreted as an
      improvement in one response category. Functional data methodology was used for some graphical
      representations. Stacked barplots over time will be presented for categorical variables. To
      analyse week changes in daily variables Generalized Estimating Equation (GEE) models were
      adjusted (treating variables as continuous).
    

Intervention name(s): Kiwifruit
Intervention type(s): Other
Intervention description(s): Throughout the five-week study period the patient had to continue their normal eating habits and exercise regime.
Other intervention name(s): Green kiwifruits (Actinidia deliciosa var Hayward)
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Funtional constipation; Kiwifruit; Health promotion