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Iran J Public Health, Vol. 44, No.10, Oct 2015, pp.1309-1321 Review Article
1309 Available at: http://ijph.tums.ac.ir
Fruit and Vegetable Intake: Benefits and Progress of Nutrition
Education Interventions- Narrative Review Article
Dhandevi PEM, *Rajesh JEEWON
Dept. of Health Sciences, Faculty of Science, University of Mauritius, Réduit, Mauritius
*Corresponding Author: Email: r.jeewon@uom.ac.mu
(Received 10 Apr 2015; accepted 10 Aug 2015)
Introduction
“Fruits and vegetables (F&V) are considered in
dietary guidance because of their high concentra-
tions of dietary fiber, vitamins, minerals, especially
electrolytes; and more recently phytochemicals,
especially antioxidants” (1). Various reviews have
associated low intake of fruits and vegetables with
chronic diseases such as cardiovascular diseases,
blood pressure, hypercholesterolemia, osteoporo-
sis, many cancers, chronic obstructive pulmonary
diseases, respiratory problems as well as mental
health (2- 6). Despite an increasing focus on the
health benefits of fruits and vegetables, their con-
sumption is below the recommended intake
among adults (7, 8). Therefore, considering how
nutritional related health problems have risen
drastically globally, it seems critical that formal
nutrition education aiming to increase knowledge
and fruits and vegetables intake be given priority
in health education programs and health promo-
tion. This review provides an insight into the im-
portance of fruits and vegetables as well as the
Abstract
Background: Sufficient intake of fruits and vegetables has been associated with a reduced risk of chronic diseases and
body weight management but the exact mechanism is unknown. The World Health Organisation and Food and Agri-
culture of the United Nation reports recommend adults to consume at least five servings of fruits and vegetables per
day excluding starchy vegetables. This review focuses on the importance of fruits and vegetables as well as the benefits
and progress of nutrition education in improving intake.
Methods: For this narrative review, more than 100 relevant scientific articles were considered from various databases
(e.g Science Direct, Pub Med and Google Scholar) using the keywords Fruit and vegetable, Nutrition education, Body
weight, Obesity, Benefits and challenges.
Results: Existing data suggests that despite the protective effects of fruits and vegetables, their intakes are still inade-
quate in many countries, especially developing ones. Consequently enhancing strategies to promote fruit and vegetable
intake are essential for health promotion among population. A number of reviews confirm that a well planned and
behaviour focused nutrition education intervention can significantly improve behaviour and health indicators.
Conclusion: Despite challenges in nutrition education intervention programs, they are considered as a good invest-
ment in terms of cost benefit ratio. Rapid improvement in trends of nutrition education can be seen in many countries
and majority of interventions has been successful in increasing fruits and vegetables intake. It is recommended that
health professionals use multiple interventions to deliver information in several smaller doses over time to ensure im-
proved outcomes.
Keywords: Fruit and vegetable, Nutrition education intervention, Body weight, Obesity, Benefit and challenges.
Pem & Jeewon: Fruit and Vegetable Intake: Benefits and Progress …
Available at: http://ijph.tums.ac.ir 1310
benefits and progress of nutrition education in
improving intake.
Importance of F&V in the diet
Sufficient intake of fruit and vegetables (F&V) has
been related epidemiologically with reduced risk
of many non-communicable diseases. Currently,
much interest are focused on the vital role of an-
tioxidants which impart bright colour to F&V and
act as scavengers cleaning up free radicals before
they cause detrimental health effects (9). Moreo-
ver, fibers found in F&V have been shown to re-
duce intestinal passage rates by forming a bulk,
leading to a more gradual nutrient absorption (10)
hence preventing constipation. They can be fer-
mented in the colon, increasing the concentration
of short chain fatty acids having anticarcinogenic
properties (11) and maintaining gut health. Several
studies have highlighted the CVD risk-reducing
potential of F&V whereby their intake were
strongly associated with lower cardiovascular risk
factors such as lower blood pressure (BP), choles-
terol and triacylglycerol thus preventing premature
cardiovascular disorders (2). Recently Habauzit et
al. (12) reported that fruits containing a high
amount of anthocyanins, flavonols and procya-
nidins, such as berries, grapes and pomegranate
are effective at decreasing cardiovascular risk
while citrus fruits and apples had a moderate ef-
fect on BP and blood lipid level. An increased
consumption of carotenoid-rich F&V maintains
the cholesterol level in blood since they reduce
oxidative damage and cause an increase in LDL
oxidation resistance (13). An increased consump-
tion of cruciferous vegetables was also reported to
cause a decrease in the risk of intestinal, bowel,
thyroid, pancreatic and lung cancer (4).
F&V have also been suggested to prevent osteo-
porosis in adults mainly for their rich sources of
calcium and other vitamins which are vital in bone
health (3). The high fiber content of F&V may
play a role in calcium absorption and reduce the
„acid load‟ of the diet (14) enhancing bone for-
mation and suppressing bone resorption which
consequently result in greater bone strength (15).
Moreover, phytoingredients in F&V such as
gooseberry, curcumin, and soya isoflavones have
shown to be protective against lens damage which
occurs due to hyperglycemia (16) and certain fla-
vonoids such as quercetin can prevent oxidative
stress in the pathogenesis of glaucoma (17). Also,
a high intake of F&V was inversely associated
with the risk of COPD and respiratory symptoms
(5). Higher total fruit and vegetable intake is also
associated with lower risk of cognitive decline
hence proved beneficial for mental health (6, 18).
Based on available evidence, a clear relationship
between F&V and diseases has been well estab-
lished however no protective effect of overall fruit
and vegetable intake (FVI) against lung diseases
were found. Green leafy vegetables, rather than
fruit, were suggested to have a genuine protective
effect against lung cancer (19). Risk of proximal
colon cancer, rectal cancer (20) and aggressive and
non-aggressive urothelial cell carcinomas (21) are
not associated with FVI and no protective role
were seen on the risk of endometrial cancer in
post menopausal women (22). The accepted rec-
ommendation is to consume a variety of F&V be-
cause studies demonstrate that a combination of
F&V have more potential benefits rather than a
single fruit or vegetable (23). However further
studies are warranted.
Fruits and Vegetable Intake (FVI), Body
Weight and Obesity
Interestingly, phytochemicals in F&V have been
found to act as anti-obesity agents because they
may play a role in suppressing growth of adipose
tissue (1, 24). Adiposity is closely related to bi-
omarkers of oxidative stress and inflammation
and a diet rich in F&V can modify these adiposity
related metabolic biomarkers in overweight wom-
en (25). A recent study by Vilaplana et al. (26)
demonstrated that Carica papaya and Morinda citrifo-
lia exhibited high lipase inhibition which can be
considered as potential options for the manage-
ment of obesity and maintaining body weight. To
date, the red varieties of Allium cepa, Lactuca sativa,
Capsicum annum, Brassica oleracea var sabellica and or-
ange-fleshed type of Ipomoea batatas appear to be
the richest vegetables sources of potential anti-
obesity phytochemicals that can control the initia-
tion and development of obesity (27).
Iran J Public Health, Vol. 44, No.10, Oct 2015, pp. 1309-1321
1311 Available at: http://ijph.tums.ac.ir
It is also understood that fruits and non-starchy
vegetables are very low in energy since they con-
tain high amount of water and fiber and can be
consumed in a relatively larger amount contrib-
uting to increased satiety to maintain normal
weight (28). Fibers also form a gel-like environ-
ment in the small intestine, resulting in reduced
activity of the enzymes involved in the digestion
of fat, protein and carbohydrates (29). Hence an
increased FVI can help to ease weight loss and
this can be achieved when F&V displace high-en-
ergy-dense foods such as saturated fats, sugar (30)
so that the overall energy density of the diet is re-
duced (31). Additionally, fruits have been sug-
gested to prevent obesity since they add up to die-
tary variety both between and within food groups
and palatability to the diet which has been re-
vealed to be an important predictor of body fat
(32). However discrepancies exist with respect to
F&V with high glycemic index carbohydrates that
are related to a more immediate decrease in appe-
tite and increase in food intake in the short term
(33). High consumption of fructose in F&V is re-
lated to obesity in rodents but no effect has yet
been demonstrated in humans (34). FVI in over-
weight and obese people is much lower than the
recommendation since they tend to restrict intake
of these F&V when trying to lose weight.
A significant relationship was observed between
BMI and vegetable intake whereby overweight par-
ticipants had lower intake of vegetables (35-
37).This finding is consistent to that of Epuru et al.
(38) who also found a clear trend between preva-
lence of obesity and low FVI. Furthermore given
that fruits are often eaten raw but vegetables are
frequently prepared by adding fatty substances (e.g.
oil while frying) which reduce the low energy dense
uniqueness of vegetables, nutritionists should be
careful when promoting FVI among population
because the idea may not work with all target popu-
lation. For instance, the intake of vegetables is as-
sociated with a higher risk of obesity in Chinese
adults due to use of oil for stir frying vegetables
and this highlights the importance of choosing the
right cooking methods (39). Interestingly, many
studies report a decrease in body weight with in-
creased FVI (40- 42). For instance, in a 10 year fol-
low up study, high FVI reduced long-term risk of
weight gain and obesity among Spanish adults (43,
44) demonstrated greater weight loss from high
vegetable intake when a high vegetable diet was
compared with a control diet comprised of „usual
intake‟.
Global Intake of Fruits and Vegetables
According to World Health Organisation STEP-
wise approach to surveillance surveys on chronic
disease risk factors conducted in several African
countries including Mauritius and in line with ex-
isting Food and Agriculture Organisation data,
fruit and vegetable intake (FVI) levels were found
to be below the recommended daily intake of
400g/person (45). With the current „5 A day‟ mes-
sage, a large gap still exists between the recom-
mended and actual intake and many worldwide are
not receiving the quantity or variety of F&V that
they should have (46, 47). Table 1 shows the mean
fruits and vegetables intake (FVI) in selected
countries.
Available data reveals that the average FVI is not
positively linked to the status of the country since
greater consumption can be seen in developing
countries such as Uganda and PR China compared
to developed countries such as Denmark, Germa-
ny, UK and France. Data from GEMS/Food clus-
ter diet shows that in US, mean F&V intake is
189.30 g/day and 255 g/day respectively, and re-
cently, adults were found to have F&V about 1.1
times and 1.6 times/day respectively (48). F&V are
consumed in the amount of 146.81 g/day and
176.96 g/day respectively in Hong Kong account-
ing for a total of 324 g/day (49). 209 g/day and
228.6 g/day F&V were reported among adults re-
spectively in Germany and recent German Health
Interview and Examination Survey data report that
women and men consume 3.1 and 2.4 servings of
F&V per day respectively (50). Mean F&V were
179g/day and 133g/day respectively in Malaysia
(51). Current data based from the Canadian Com-
munity Health Survey which measured the number
of times participants consumed F&V, rather than
the actual quantity consumed, reported that only
40.8% Canadians aged >12 years consume F&V 5
or more times per day (52).
Pem & Jeewon: Fruit and Vegetable Intake: Benefits and Progress …
Available at: http://ijph.tums.ac.ir 1312
Table 1: Fruits and vegetable consumption in adults in selected countries
Country
Year of up-
dated data
Mean Fruit intake
( g/d )
Mean Vegetable in-
take ( g/d)
Developed
Hong Kong ( SAR, PR China)
2010
146.81
176.96
Denmark*
2013
151.70
162.08
Germany*
2013
171.36
118.02
UK*
2013
130.02
97.86
France*
2013
136.56
145.15
US**
2015
189.30
255.00
Netherlands*
2013
102.36
127.79
Italy*
2013
90.83
150.81
Austria*
2013
163.58
89.52
Developing
Malaysia
2012
179.00
133.00
India**
2015
158.20
105.70
PR China**
2015
222.10
262.80
Ghana**
2015
149.80
36.10
Ethiopia**
2015
114.70
51.20
Uganda**
2015
464.10
24.40
Samoa**
2015
441.00
9.10
* Data from EFSA database, updated 2013 (53)
** Data from GEMS/Food database, updated 2015 (54)
Likewise, The Healthy People 2010 report (8)
stated that the trends in FVI over the previous
decade were relatively flat and has not been able
to meet the Healthy People 2010 goals. The latter
targets increasing to 75% the proportion of per-
sons aged > 2 years who consume two or more
servings of fruit daily and to 50% those who con-
sume three or more servings of vegetables daily.
Recently published Global Phytonutrient Report
(55) reveals that to achieve the WHO recommen-
dation, most adults should at least double their
current intake of F&V worldwide. Many countries
like France, Spain (56), US, (57) and Mauritius
(58) follow the „5 A Day‟ recommended guidelines.
However presently, it has been reported that 5
servings a day are not enough since those con-
suming 7 or more servings of fruits and vegetables
a day, are having more health benefits and pro-
longed lives [e.g. those who ate 5 to 7 servings of
fruits and vegetables per day had a 36% lower risk
of dying from any cause; 3 to 5 servings was asso-
ciated with 29% lower risk while 1 to 3 servings
was linked with a 14% lower risk] (59). Countries
like Canada, Australia, and Denmark have a rec-
ommendation in the range of 6 to10 servings of
F&V daily (60- 62). Since different countries are
using different guidelines, the ideal recommenda-
tion of F&V is still being debated and there is
need of a unified message to promote intake
around the world.
Requirement and strategies for nutrition edu-
cation to boost FVI
Nutrition education is defined as “any combina-
tion of educational strategies, accompanied by en-
vironmental supports, designed to facilitate volun-
tary adoption of food choices and other food and
nutrition-related behaviors conducive to health
and wellbeing”(63). Educational interventions to
encourage Americans to improve their diets may
prevent rising incidence of heart diseases and save
health care expenditures (64). The high prevalence
of nutrition-related chronic illnesses with obesity
and overweight among the most challenging and
steadily rising public health problems suggests that
nutrition education needs to be a priority for
Iran J Public Health, Vol. 44, No.10, Oct 2015, pp. 1309-1321
1313 Available at: http://ijph.tums.ac.ir
adults and nutrition educators must be knowl-
edgeable about diet and disease relationships spe-
cific to the population (65). The scope of nutrition
education is broader than just educating about
nutrition in relation to personal health. It can cov-
er a wide range of issues and topics such as an in-
crease in quantity and quality of foods, ways of
improving nutritive value of a diet, importance of
sanitary food handling practices at home, in mar-
ket, factories and institutions serving food to large
numbers of people such as schools, hospitals and
restaurants (66) hence ensuring food safety and
reducing morbidity.
To meet current F&V recommendation, many
countries have developed targeted campaigns and
interventions to increase FVI to adequate level.
Pollard et al. (67) monitored changes in behaviors
regarding FVI in Western Australia before and
after the "Go for 2&5" and found that most
changes mainly in knowledge, attitudes, and be-
haviors concerning FVI took place after the cam-
paign. In particular, respondents who correctly
identified the recommended intake of F&V dou-
bled indicating that health campaign with nutrition
education as an integral component is fruitful.
Resnicow et al. (68) also reported that an “Eat for
Life program”, a multicomponent intervention to
increase FVI conducted resulted in a significant
increase in FVI. These studies are consistent to
that of Ammerman et al. (69) who reviewed the
efficacy of behavioral interventions to modify FVI
emphasizing on studies in North America, Europe
and Australia and noted a significant effect in in-
creasing FVI. Moreover, in an intervention using a
general nutrition course, participants increased
consumption of not only total F&V but also fresh
F&V along with a significant decrease in intake of
high energy density French fries (70). Bensley et al.
(71) compared traditional nutrition education to
that of an internet one and found that both re-
quired follow-up counseling to achieve FVI levels
and in both interventions, those who were pro-
vided counseling consumed more vegetables,
fruits and fruit juice. In order to achieve and sus-
tain FVI at the recommended levels, intervention
alone is not enough as it requires a combination
of other approaches such as social marketing, be-
havioral economics approaches, and technology
based behavior change models to ensure that re-
quired goals are met (72). The findings from pre-
vious reviews are interesting showing that most of
the interventions lead to an increased consump-
tion of F&V at least in the short term. However
no such review has conducted a Meta analysis
quantifying the effectiveness of the interventions.
Few intervention reviews have been done to see
whether nutrition education is effective. One of
such review is that of Taylor et al. (73) who con-
ducted a Meta analysis of various intervention
studies whereby five of them reported significant
positive changes in weight and BMI. Four studies
had effective interventions targeting determinants
of dietary intake and dietary behaviors and nutri-
tional intake. However uncertainty do remains due
to insufficient details provided for nutrition inter-
vention protocols, inconsistency in approach of
delivery and comparisons between delivery modes
and content of information provided to partici-
pants between studies. Eyles et al. (74) found that
tailored nutrition education was a promising strat-
egy for improving the diets of adults over the long
term but stated that future studies should ensure
adequate reporting of research design and reduce
the chances of false-positive findings via more
objective measures of diet. Likewise tailored inter-
ventions were more effective than non-tailored
interventions in improving the short-term dietary
behaviors of participants whereby delivery of in-
formation in several smaller doses over time was
more likely to improve effectiveness (75). Lara et
al. (76) noted that nutrition education was a signif-
icant factor in increasing fruit and vegetable in-
takes and are therefore effective, sustainable in the
long term and considered it to be of public health
significance. Table 2 below summarises findings
of some successful nutrition education interven-
tion.
Overall nutrition education contributes signifi-
cantly to a change in food and nutrition related
behaviors but where many components are in-
volved, it achieves positive results in some and
negative in others. Guillaumie et al. (77) con-
cluded that most psychosocial variables signifi-
cantly increased in an intervention group exposed
Pem & Jeewon: Fruit and Vegetable Intake: Benefits and Progress …
Available at: http://ijph.tums.ac.ir 1314
to a nutrition education plan with the exception of
vegetable intake. Assema et al. (78) found an inter-
vention effect in saturated fat intake during the
main meal and fruit juice consumption but not for
daily intake of fruit and vegetables. Contento et al.
(79) stated that “the reported effectiveness, or lack
thereof, of nutrition education interventions in
various studies depends on many factors, includ-
ing the nature, duration, and power of the inter-
ventions and the degree to which the interven-
tions were implemented as designed”. The author
remarked that in order to assure the success of a
nutrition education strategy, major implications
need to be considered such as developing and
testing instruments with each new target audience
before any intervention study, it will then be fea-
sible to make judgments about the effectiveness
of nutrition education and impact of interventions
on mediating variables would be understood.
Moreover, to be successful, nutrition education
needs to be much more comprehensive than giv-
ing basic nutrition information. It should address
food preferences and sensory affective factors;
person-related factors such as perceptions, beliefs,
and attitudes; meanings and social norms; and en-
vironmental factors (80). Effective nutrition inter-
ventions should have a behavioral focus that will
reduce the targeted risk factors and comprise
strategies that are developmentally and culturally
appropriate (81). Barriers pertaining to health pre-
ventive behaviors along with the determinants of
intake should be taken into account and solutions
should be designed (67). For example, low income
groups can be targeted to opt for cheap sources of
F&V to meet the 5 a day demand (78). Where
possible, consumption of tropical fruits should be
encouraged and at the same time this will increase
the profits of fruit vendors and that of the country
at large. Men can be targeted through educational
campaigns at work and through eye catching ad-
vertisement (73). The government can review tax
on F&V and promote more display areas such as
farmers markets and shops in most regions to in-
crease availability (56). Involvement of stakehold-
ers, ministries, and legislation at higher level can
be thought-out concerning produce and distribu-
tion channel related factors as well as for food
labeling which are sometimes misleading and dif-
ficult to interpret (82). Furthermore, accounting
for the high prevalence of diabetes with 387 mil-
lion cases reported globally which is expected to
rise to 592 million by 2035 (83) and with more
than 1.9 billion adults having obesity problems
(84), diabetes concept of not consuming certain
fruits may lead to further health detriment. Re-
search shows that diabetic people would benefit
greatly from consuming a variety of F&V, which
help to lower degrees of inflammation, to have
better glycemic control, and reduce odds of dia-
betic retinopathy (85). Additionally, there is no
evidence to support that fructose present in fruits
under normal conditions has a negative impact on
the glycemic control in Type 2 diabetes (86).
However, the role of fructose and fruit sugars in
the development of the current obesity and dia-
betic epidemic remains controversial and the gen-
eral population including overweight and obese
person should be given correct information. Nu-
trition intervention programs should aim healthy
food habits including the consumption of F&V
together with physical exercise aiming to reduce
body weight and improve health status. Messages
and interventions should be creative, engaging,
supportive and inexpensive (87) with realistic
goals ensuring that the Mauritian population, also
type 2 diabetic and obese people understand the
message of having fruits just as the general popu-
lation, without fearing worsening of their glycemic
control.
Challenges on nutrition education interven-
tion programs
Despite clear evidence on the benefits of nutrition
education intervention, there are major challenges
that are faced by nutrition educators. These are: a)
realistic educational goals, b) thorough research
designs, c) explicit theoretical bases, and d) valid
and reliable measurements (88). Assuring effective
communication skills of nutrition educators and
the quality of nutrition education or behavior
change interventions implemented is questionable
(89). Quality assurance tools and validated guide-
lines targeting specific target population are uncer-
tain (90).Monitoring and evaluation within inte-
Iran J Public Health, Vol. 44, No.10, Oct 2015, pp. 1309-1321
1315 Available at: http://ijph.tums.ac.ir
grated programs does not always capture the im-
pact on nutritional status sufficiently or in a timely
manner to allow for improving implementation
(91). Methodological challenge such as small sam-
ple size and mostly female respondents may pre-
vent experimentally conclusive and sustainable
evidence (78). Nutrition education is also influ-
enced by several barriers (92- 95) and predispos-
ing factors such as attitudes, beliefs, values, capac-
ity, self-efficacy, individual differences (96) that
need to be overcome. Thus, several drawbacks of
nutrition education deserve attention.
Conclusion
The relationship between FVI and reductions in
risk for many major health problems is strongly
supported in many research studies but the effects
of F&V on plasma lipid levels, diabetes, and body
weight have yet to be explored. Still, F&V are be-
lieved to be protective against adiposity and are
considered as a potential treatment in the manage-
ment of obesity. Despite their numerous health
benefits, few countries fulfilled 400g daily require-
ment for FVI. Many nutrition education strategies
have positively impacted on people‟s nutrition and
health behavior yet there are many factors which
need to be considered and challenges that need to
be overcome when designing nutrition education
strategies. To be successful, nutrition education
needs to be much more comprehensive than giv-
ing basic nutrition information. Current focus is
on the effectiveness of methods of information
dissemination and validation of educational tools.
It is important for nutrition educators to deal with
dietary behaviors that are associated with specific
diseases adapted to explicit target population. Nu-
trient-based information alone is inadequate. Most
successful strategies have been the delivery of in-
formation in several smaller doses over time. Alt-
hough promoting healthy lifestyles is a challenge,
it can be realized by focusing on positive “to-do”
behaviors, rather than on “not-to-do” behaviors
aiming at increasing the percentage of people
adopting healthier eating habits.
Ethical considerations
Ethical issues (Including plagiarism, informed
consent, misconduct, data fabrication and/or fal-
sification, double publication and/or submission,
redundancy, etc.) have been completely observed
by the authors.
Acknowledgement
The Department of Health Sciences, Faculty of
Science, University of Mauritius is acknowledged
for research support. The authors declare that
there is no conflict of interests
References
1. Slavin JL, Lloyd B (2012). Health Benefits of
fruits and vegetables. Adv Nutr, 3(4):506-16.
2. Adebawo O, Salau B, Ezima E et al. (2006). Fruits
and vegetables moderate lipid cardiovascular
risk factor in hypertensive patients. Lipids
Health Dis, 5:14.
3. Park HM, Heo J, Park Y (2011). Calcium from
plant sources is beneficial to lowering the risk
of osteoporosis in postmenopausal Korean
women. Nutr Res, 31: 27–32.
4. Williamson G (1996). Protective effects of fruits
and vegetables in the diet. J Nutr Food Sci, 96
(1): 6-10.
5. Celik F, Topcu F (2006). Nutritional risk factors
for the development of chronic obstructive
pulmonary disease (COPD) in male smokers.
Am J Clin Nutr, 25(6):955-961.
6. Payne ME, Steck SE, George RR, Steffens DC
(2012). Fruit, Vegetable, and Antioxidant In-
takes Are Lower in Older Adults with Depres-
sion. J Acad Nutr Diet, 112: 2022-2027.
7. Schneider M, Norman R, Steyn N, Bradshaw D
(2007). Estimating the burden of disease at-
tributable to low fruit and vegetable intake in
South Africa in 2000. S Afr Med J, 97 (8).
8. Morbidity and Mortality Weekly Report (2010).
State- Specific Trends in Fruit and Vegetable
Consumption Among Adults- United States,
2000-2009. MMWR. 59 (35).
http://www.cdc.gov/mmwr/pdf/wk/mm59
35.pdf
Pem & Jeewon: Fruit and Vegetable Intake: Benefits and Progress …
Available at: http://ijph.tums.ac.ir 1316
9. Kaur C, Kapoor HC (2001). Antioxidants in fruits
and vegetables: the millennium's health. Int J
Food Sci Technol, 36: 703-725.
10. Anderson, J. Perryman S, Young L, Prior S
(2010). Dietary Fibre Fact. Sheet No. 9.333;
Colorado State University: Fort Collins, CO,
USA.
http://www.ext.colostate.edu/pubs/foodnut/
09333.pdf (accessed January 2015)
11. Lattimer JM, Haub MD (2010). Effects of Dietary
Fibre and Its Components on Metabolic
Health. Nutrients, 2: 1266-1289.
12. Habauzit V, Milenkovic D, Morand C (2013).
Vascular Protective Effects of Fruit Polyphe-
nols. In. Polyphenols in Human Health and Disease.
Eds, Watson R, Preedy V, Zibadi S. 1st ed,
Elsevier Inc. London, pp. 875-893.
13. Southon S (2000). Increased fruit and vegetable
consumption within the EU: potential health
benefits. Food Res Int, 33(3–4):211–217.
14. New S (2001). Fruit and vegetable consumption
and skeletal health: is there a positive link? Nu-
trition Foundation. Nutr Bull, 26: 121–125.
15. Shen CL, Bergen VV, Chyu MC et al. (2012).
Fruits and dietary phytochemicals in bone pro-
tection. Nutr Res, 32: 897 – 910.
16. Agte V, Gite S (2014). Diabetic Cataract and Role
of Antiglycating Phytochemicals. In: Handbook
of Nutrition, Diet and the Eye. Ed, VR Preedy. 1st
ed, Elsevier Inc. Burlington, pp. 131–140.
17. Miyamoto N, Izumi H, Tawara A, Kohno K
(2014). Quercetin and Glaucoma. In: Hand-
book of Nutrition, Diet and the Eye. Eds, VR
Preedy. 1st ed, Elsevier Inc. Burlington, pp. 97–
103.
18. Mc Martin SE, Jacka FN, Colman I (2013). The
association between fruit and vegetable con-
sumption and mental health disorders: Evi-
dence from five waves of a national survey of
Canadians. Prev Med, 56: 225-230.
19. Dosil-Diaz O, Ruanao-Ravina A, Gestal-Otero JJ,
Barros-Dios JM (2008). Consumption of fruit
and vegetables and risk of lung cancer: A case-
control study in Galicia, Spain. J Nut, 24: 407–
413.
20. Annema N, Heyworth JS, Mc- Naughton SA et
al. (2011). Fruit and Vegetable Consumption
and the Risk of Proximal Colon, Distal Colon,
and Rectal Cancers in a Case-Control Study in
Western Australia. J Am Diet Assoc, 111:1479-
1490.
21. Ros MM, Bueno-De-Mesquita Hb, Kampman E
et al. (2012). Fruit and vegetable consumption
and risk of aggressive and non-aggressive
urothelial cell carcinomas in the European
Prospective Investigation into Cancer and Nu-
trition. Eur J Cancer, 48:3267–3277.
22. Kabat GC, Park Y, Hollenbeck AR, Schatzkin A,
Rohan, TE (2010). Intake of fruits and vegeta-
bles, and risk of endometrial cancer in the
NIH-AARP Diet and Health Study. J Cancer
Epi Detec Prev, 34; 568–573.
23. Fruits and Veggies more matters (2015). Fruit &
Vegetable variety.
http://www.fruitsandveggiesmorematters.org
/fruit-and-vegetable-variety
24. Castejon MG, Casado AR (2011). Dietary phyto-
chemicals and their potential effects on obe-
sity: A review. Pharm Res, 64:438–455.
25. Yeon JY, Kim HS, Sung MK (2012). Diets rich in
fruits and vegetables suppress blood bi-
omarkers of metabolic stress in overweight
women. Am J Prev Med, 54: S109–S115.
26. Vilaplana AG, Baenas N, Villano D et al. (2014).
Evaluation of Latin-American fruits rich in
phytochemicals with biological effects. J Funct
Foods, 7: 599-608.
27. Williams DJ, Edwards D, Hamernig I et al.
(2013). Vegetables containing phytochemicals
with potential anti-obesity properties: A re-
view. Food Res Int, 52: 323–333.
28. Tohill BC, Seymour J, Serdula M et al. (2004).
What Epidemiologic Studies Tell Us about the
Relationship between Fruit and Vegetable
Consumption and Body Weight? Nutr Rev, 62
(10): 365-374.
29. Alinia S, Hels O, Tetens I (2009). The potential
association between fruit intake and body
weight – a review. International Association
for the Study of Obesity. Obes Rev, 10: 639–
647.
30. Kanungsukkasem U, Ng N, Minh Vet al. (2009).
Fruit and vegetable consumption in rural
adults population in INDEPTH HDSS sites in
Asia. Global Health Action Supplement.
http://www.globalhealthaction.net/index.php
/gha/article/viewFile/1988/2415
31. Rolls BJ (2010). Increasing F&V consumption to
reduce energy intake. The scientific Newsletter.
46:1-4.
http://www.ifava.org/media/35014/IFAVA4
6_0610_Reduce_Energy.pdf
Iran J Public Health, Vol. 44, No.10, Oct 2015, pp. 1309-1321
1317 Available at: http://ijph.tums.ac.ir
32. Mccrory MA, Fuss PJ, Saltzman E, Roberts SB
(2000). Dietary Determinants of Energy Intake
and Weight Regulation in Healthy Adults. J
Nutr, 130: 276S–279S.
33. Tetens I, Alinia S (2009). The role of fruit con-
sumption in the prevention of obesity. J Hortic
Sci Biotech, 47-51.
34. Tappy L, Le KA (2010). Metabolic Effects of
Fructose and the Worldwide Increase in Obe-
sity. Physiol Rev, 90: 23–46.
35. Dehgan M, Danesh NA, Merchant AT (2011).
Factors associated with fruit and vegetable
consumption among adults. J Hum Nutr Diet,
24:128–134.
36. Dunneram Y, Ramasawmy D, Pugo-Gunsam P,
Jeewon R (2013). Determinants of eating hab-
its among pre-retired and post-retired Mauri-
tians. Int J Food Sci Nutr, 2(3):109-115.
37. Fokeena WB, Jeewon R (2012). Is There an As-
sociation between Socioeconomic Status and
Body Mass Index among Adolescents in Mau-
ritius? Sci World J, 1-9.
38. Epuru S, Eideh A, Bayoudh AAA, Alshammari E
(2014). Fruit and vegetable consumption
trends among the female university students in
Saudi Arabia. ESJ, 10(12): 223-237.
39. Shi Z, Hu X, Yuan B et al. (2008). Vegetable-rich
food pattern is related to obesity in China. Int J
Obes, 32: 975–984.
40. Oliveria MC, Sichieri R, Mozzer RV (2008). A
low-energy-dense diet adding fruit reduces
weight and energy intake in women. Appetite,
51 (2): 291 – 295.
41. Ledikwe JH, Blanck HM, Kettel KL et al. (2006).
Dietary energy density is associated with en-
ergy intake and weight status in US adults. Am
J Clin Nutr, 83 (6): 1362-1368.
42. Whigham LD, Valentine AR, Johnson LK et al.
(2012). Increased vegetable and fruit consump-
tion during weight loss effort correlates with
increased weight and fat loss .J Nutr Diabetes, 2
(10): e48.
43. Vioque J, Weinbrenner T, Castello A et al.
(2008).Intake of Fruits and Vegetables in Rela-
tion to 10-year Weight Gain Among Spanish
Adults. Int J Obesity, 16: 664–670.
44. Tapsell LC, Batterham MJ, Thome RL et al.
(2014). Weight loss effects from vegetable in-
take: a 12-month randomised controlled trial.
Eur J Clin Nutr, 68: 778–785.
45. PROFAV (2011). Promotion of Fruit and Vege-
tables for Health. African Regional Workshop
Arusha, Tanzania: 26-30 September.
http://www.fao.org/fileadmin/templates/ag-
phome/documents/horticulture/WHO/arus
ha/PROFAV_2011_programme.pdf
46. Serdula MK, Gillespie C, Kettel-khan L et al.
(2004). Trends in Fruit and Vegetable Con-
sumption Among Adults in the United States:
Behavioral Risk Factor Surveillance System,
1994–2000. Am J Public Health, 94 (6): 1014-8.
47. Krebs- smith SM, Guenther PM, Subar AF et al.
(2010). Americans Do Not Meet Federal Die-
tary Recommendations. J Nutr, 140: 1832–
1838.
48. Centers for Disease Control and Prevention
(2013). State Indicator Report on Fruits and
Vegetables 2013. Atlanta, GA: Centers for
Disease Control and Prevention, U.S Depart-
ment of Health and Human Services, 2013.
http://www.cdc.gov/nutrition/downloads/St
ate-Indicator-Report-Fruits-Vegetables-
2013.pdf
49. The Chinese University of Hong Kong. Food and
environmental hygiene department, (2010).
Hong Kong population based food consump-
tion survey 2005-2007 final report.
http://www.cfs.gov.hk/english/programme/
pro-
gramme_firm/files/1st_HKTDS_Report_e.p
df
50. Mensink GDM, Truthmann J, Rabenberg M et al.
(2013). Fruit and Vegetables intake in Ger-
many. Bundesgesundheitsbl, 56:779–785.
51. Izzah NA, Aminah A, Pauzi MA et al. (2012).
Patterns of fruits and vegetable consumption
among adults of different ethnics in Selangor,
Malaysia. Int Food Res J, 19 (3): 1095-1107.
52. Health Fact Sheet- Fruit and vegetable consump-
tion, 2013. Statistics Canada, 2014.
http://www5.statcan.gc.ca/olc-
cel/olc.action?ObjId=82-625-
X201400114018&ObjType=47&lang=en
53. European Food Safety Authority (2013). The
EFSA Comprehensive European Food Con-
sumption Database.
http://www.efsa.europa.eu/en/datexfooddb/
datexfooddbspecificdata.htm
54. Global Environment Monitoring System
(GEMS/ Food) (2012). World Health Organi-
sation, 2015.
Pem & Jeewon: Fruit and Vegetable Intake: Benefits and Progress …
Available at: http://ijph.tums.ac.ir 1318
http://www.who.int/nutrition/landscape_ana
lysis/nlis_gem_food/en/
55. Global Phytonutrient Report. Nutrilite Health In-
stitute Center for optimal health. Available
from:
http://www.nutrilite80th.com/FINAL_Nutri-
lite_Global_Phytonutrient_Report_June%202
014.pdf
56. Louis Bonduelle Foundation. How can the con-
sumption of vegetables in Europe be in-
creased? 1-7. Available from:
http://www.fondation-louisbon-
duelle.org/uploads/tx_flbnews/how-can-the-
consumption-of-vegetables-in_europe-be-in-
creased-file-louis-bonduelle-foundation-
2011_05.pdf
57. Fruits & Veggies More Matters (2013a). About
fruit & veggies more matters USA.
http://www.fruitsandveggiesmorematters.org
58. Ministry Of Health and Quality Of Life. Republic
of Mauritius. National Plan of Action for Nu-
trition, 2009-2010. Available from:
http://health.govmu.org/English/Documents
/nut1-8.pdf
59. Oyebode O, Gordon-Dseagu G, Walker A, Min-
dell JS (2014). Fruit and vegetable consump-
tion and all-cause, cancer and CVD mortality:
analysis of Health Survey for England data.
J Epidemiol Community Health, 68:856–862.
60. Ministry Of Health Canada (2007). Eating well
with Canada‟s food guide. Available from:
http://www.health.gov.nl.ca/health/findhealt
hservices/canada_food_guide_first_nations_in
uit_metis.pdf
61. Australia‟s Food & nutrition (2012). Australian
Institute Of Health And Welfare. Available
from:
http://www.aihw.gov.au/workarea/download
asset.aspx?id=10737422837
62. Danish Health Agency (2008).6 Om Dagen. Den-
mark response to „„Towards a possible Euro-
pean school fruit scheme. Consultation docu-
ment for impact assessment. Available from:
http://ec.europa.eu/agriculture/sfs/docu-
ments/public/replies/denmark6aday_en.pdf
63. Contento IR (2008). Nutrition education: linking
research, theory, and practice. J Clin Nutr,
17(1):176-179.
64. Phillips (2010). The Public Value of Nutrition
Education. U.S Department of Agriculture
and Wisconsin counties cooperating. Available
from:
http://flp.ces.uwex.edu/files/2012/03/Fo-
cusOnScholarship.pdf
65. Johnson MA, Park S, Penn D et al. (2008). Nutri-
tion Education Issues for Older Adults. FFCI,
13 (3). Available from:
http://ncsu.edu/ffci/publications/2008/v13-
n3-2008-winter/johnson-park-penn-mcclel-
land-brown-adler.php
66. Bosley, B (1996). Nutrition Education. In: Nutri-
tion in Preventive medicine: the major deficiency syn-
dromes, epidemiology, and approaches to control. Eds,
G.H Beaton & J.M Bengoa. Geneva: World
Health Organization, pp. 277-295.
67. Pollard C, Miller M, Woodman RJ et al. (2009).
Changes in Knowledge, Beliefs, and Behaviors
Related to Fruit and Vegetable Consumption
Among Western Australian Adults from 1995
to 2004. Am J Public Health, 99(2).
68. Resnicow IK, Jackson A, Wang T et al. (2001). A
Motivational Interviewing Intervention to In-
crease Fruit and Vegetable Intake Through
Black Churches: Results of the Eat for Life
Trial. Am J Public Health, 99 (2): 1686-1693.
69. Ammerman AS, Lindquist CH, Lohr KN, Hersey
J (2002). The efficacy of behavioral interven-
tions to modify dietary fat and fruit and vegeta-
ble intake: a review of the evidence. Prev Med,
35(1):25-41.
70. Ha EJ, Bish NC (2009). Effect of Nutrition Inter-
vention Using a General Nutrition Course for
Promoting Fruit and Vegetable Consumption
among College Students. J Nutr Educ Behav,
41(2): 103-109.
71. Bensley RJ, Anderson JV, Brusk JJ et al. (2011).
Impact of internet vs. traditional Special Sup-
plemental Nutrition Program for Women, In-
fants, and Children nutrition education on fruit
and vegetable intake. J Am Diet Assoc, (5): 749-
55.
72. Thomson CA, Ravia J (2011). A systematic re-
view of behavioral interventions to promote
intake of fruit and vegetables. J Am Diet Assoc,
111(10):1523-35.
73. Taylor PJ, Kolt GS, Vandelanotte C et al. (2013).
A review of the nature and effectiveness of nu-
trition interventions in adult males – a guide
for intervention strategies. Int J Behav Nutr Phys
Act, 10:13.
Iran J Public Health, Vol. 44, No.10, Oct 2015, pp. 1309-1321
1319 Available at: http://ijph.tums.ac.ir
74. Eyles HC, Mhurchu CN (2009). Does tailoring
make a difference? A systematic review of the
long-term effectiveness of tailored nutrition
education for adults. Nutr Rev, 67(8):464–480.
75. Gans KM, Risica PM, Strolla LO et al. (2009). Ef-
fectiveness of different methods for delivering
tailored nutrition education to low income,
ethnically diverse adults. Int J Behav Nutr Phys
Act, 6:24.
76. Lara J, Hobbs N, Moynohan PJ et al. (2014). Ef-
fectiveness of dietary interventions among
adults of retirement age: a systematic review
and meta-analysis of randomized controlled
trials. BMC Med, 12:60.
77. Guillaumie L, Godin G, Manderscheid JC et al.
(2012). The impact of self-efficacy and imple-
mentation intentions-based interventions on
fruit and vegetable intake among adults. Psychol
Health, 27 (1): 30–50.
78. Assema PV, Steenbakkers M, Rademaker C, Brug
J (2005). The impact of a nutrition education
intervention on main meal quality and fruit in-
take in people with financial problems. J Hum
Nutr Diet, 18: 205–212.
79. Contento IR, Randell JS, Basch CE (2002). Re-
view and Analysis of Evaluation Measures
Used in Nutrition Education Intervention Re-
search. J Nutr Educ Behav, 34:2-25.
80. Nutrition Education Resource Guide (2011). Cali-
fornia Department of Education. Available
from:
http://www.cde.ca.gov/ls/nu/he/documents
/nergcomplete.pdf
81. Shariff ZM, Bukhari SS, Othman N et al. (2008).
Nutrition Education Intervention Improves
Nutrition Knowledge, Attitude and Practices
of Primary School Children: A Pilot Study. Int
Electron J Health Educ, 11:119-132.
82. Food and Agriculture Organisation (2013). Chal-
lenges and issues in nutrition education.
http://www.fao.org/docrep/017/i3234e/i323
4e.pdf
83. International Diabetes Federation (2014). Diabe-
tes Atlas. Available from:
http://www.idf.org/diabetesatlas
84. World Health Organisation (2014). Obesity and
overweight. Factsheet No 311. Available from:
http://www.who.int/mediacentre/factsheets/
fs311/en/
85. Mahoney SE, Loprinzo PD (2014). Influence of
flavonoid-rich fruit and vegetable intake on di-
abetic retinopathy and diabetes-related bi-
omarkers. J Diabetes Complicat, 28:767–771.
86. Christensen AS, Viggers L, Hasselstrom K,
Gregersen S (2013). Effect of fruit restriction
on glycemic control in patients with type 2 di-
abetes – a randomized trial. Nutr J, 12:29.
87. Oosthuizen D (2010). Impact of a nutrition edu-
cation programme on nutrition knowledge and
dietary intake practices of primary school chil-
dren in Boipatong. Thesis (PhD). Vaal Univer-
sity of Technology
88. Gillespie AH, Brun JK (1992). Trends and chal-
lenges for nutrition education research. J Nutr
Educ Behav, 24: 222-226.
89. Lua PL, Elena WDWP (2012). The Impact of
Nutrition Education Interventions on the Die-
tary Habits of College Students in Developed
Nations: A Brief Review. Malays J Med Sci, 19
(1): 4-14.
90. United States Department of Agriculture
(2014).Addressing the Challenges of Conduct-
ing Effective Supplemental Nutrition Assis-
tance Program Education (SNAP-Ed) Evalua-
tions: A Step-by-Step Guide. Available from:
http://www.fns.usda.gov/sites/default/files/
SNAPEDWaveII_Guide.pdf
91. Bonevski B, Randell M, Paul C et al. (2014).
Reaching the hard-to-reach: a systematic re-
view of strategies for improving health and
medical research with socially disadvantaged
groups. BMC Med Res Methodol, 14: 42.
92. Love P, Maunder E, Green JM (2008). Are South
African women willing and able to apply the
new food-based dietary guidelines? Lessons
for nutrition educators. S Afr J Clin Nutr, 21:
17-24.
93. Eertmans A, Baeyen F, Bergh Van den (2001).
Food likes and their relative importance in hu-
man eating behaviour: review and preliminary
suggestions for health promotion. Health Educ
Res, 443-456.
94. Fila SA , Smith C (2006). Applying the Theory of
Planned Behavior to healthy eating behaviors
in urban Native American youth. Int J Behav
Nutr Phys Act, 3:11.
95. Raats MM, Sparks P (1995). Unrealistic optimism
about diet-related risks: implications for inter-
ventions. Proc Nutr Soc, 54:737-745.
96. Allan J, Johnston M, Campbell N (2008). Why do
people fail to turn good intentions into action?
The role of executive control processes in the
Pem & Jeewon: Fruit and Vegetable Intake: Benefits and Progress …
Available at: http://ijph.tums.ac.ir 1320
translation of healthy eating intentions into ac-
tion in young Scottish adults. BMC Public
Health, 8:123.
97. Anderson ES, Winett RA, Wojcik JR et al. (2001).
A computerized social cognitive intervention
for nutrition behavior: direct and mediated ef-
fects on fat, fiber, fruits and vegetables, self ef-
ficacy, and outcome expectations among food
shoppers. Ann Behav Med, 23: 88-100.
98. Campbell MK, Tessaro I, DeVellis B et al. (2002)
Effects of a tailored health promotion pro-
gram for female blue-collar workers: health
works for women. Prev Med, 34: 313-323.
99. Liu N, Mao L, Sun X et al. (2009). The effect of
health and nutrition education intervention on
women's postpartum beliefs and practices: a
randomized controlled trial. BMC Public Health,
9:45.
100. Lopez JM, Molinia JM, Chirosa LJ et al. (2013).
Implementation of a nutrition education pro-
gram in a handball team; consequences on nu-
tritional status. Nutr Hosp, 28 (3):1065-1076.
101. Shahril MR, Dali WPEW, Lua PL (2013). A 10-
Week Multimodal Nutrition Education Inter-
vention Improves Dietary Intake among Uni-
versity Students: Cluster Randomised Con-
trolled Trial. J Nutr Met, 1-11.
102. Bhurosy T, Jeewon R (2013). Effectiveness of a
Theory –Driven Nutritional Education Pro-
gram in Improving Calcium Intake among
Older Mauritian Adults. J Nutr Met, 1-16.
Iran J Public Health, Vol. 44, No.10, Oct 2015, pp. 1309-1321
1321 Available at: http://ijph.tums.ac.ir
Table 2: Summary and findings of some successful nutrition education interventions
Author, (Year), Location
Sample
Study groups
Follow-up
Outcomes
Results
Anderson (2001), USA
(97)
N= 296
-Tailored (n= 148)
-Control (n= 148)
6 months
- Fiber intake (g/1000 kcal)
- Fruit & Vegetable intake (g/1000 kcal daily)
+
+
Resnicow (2001), France
(68)
N= 861
-Comparison
-Self help intervention with 1 telephone cue call
-Self help with 1 cue call and 3 counseling calls ( motivational interviewing)
12 months
-FV intake ( servings/ day, by FFQ)
change in FVI was significantly greater in motivational interview group than in
comparison and self-help groups
+
Campbell (2002), USA (98)
N= 660
-Tailored ( n= 89)
-Control( n= 93)
6 months
- Fruit intake
-Vegetable intake ( servings/ day)
Total fat ( g/day)
+
–
–
Assema (2005), Netherlands
(78)
N= 74
Intervention (n=35)
Control (n=39)
1 month
Vegetable (g per meal)
Fruit (pieces per day)
Fruit juice (glasses per day)
Saturated fat intake ( en % per meal)
–
–
+
+
Gans et al. (2009), USA
(75)
N= 1841
- Non tailored comparison (NT) (n=451)
- Single Tailored packet (ST) (n=454)
-Multiple tailored packet (MT) (n=474)
- Multiple Re- Tailored packet (MRT) (n=462)
7 months
- Fruit & Vegetable intake (servings/day)
-Fat intake (g/day)
MT groups reported significantly higher FVI compared to other groups.
+
–
Liu et al. (2009), China
(99)
N= 410
Intervention ( n=154)
Control (n=148)
6 weeks
Fruit intake (g/day)
Vegetable intake(g/day)
Soybean & products (g/day)
Meat, poultry & Fish(g/day)
Dairy (ml/day)
Eggs (g/day)
Grain/ Cereals(g/day)
+
+
+
+
+
+
–
Guillaumie et al. (2012),
Canada
(77)
N=163
-implementation intentions (II) (n=36)
- Self Efficacy ( SE) (n=47)
- Combination of II + SE group (n=52)
- control (n=28)
3 months
Fruit & Vegetable intake
Fruit Intake
Vegetable Intake
FVI increased significantly in the II and II+ SE groups.
Slightly larger increase was observed in II+SE group
+
+
+
Lopez et al. (2013), Spain
(100)
N= 14
Control (baseline)
Intervention ( week 16)
4 months
Energy ( Kcal/day)
Protein (g/day)
Carbohydrate ( g/day)
Fat ( g/day)
Saturated Fatty Acids ( g/day)
Monounsaturated fatty acids( g/day)
Polyunsaturated fatty acids( g/day)
+
+
+
–
–
+
–
Shahril et al. (2013), Malaysia
(101)
N= 380
Intervention (n= 205)
Control (n=212)
10 weeks
Energy intake (Kcal)
Carbohydrate (%)
Calcium
Vitamin C
Thiamine
Fruits (servings/day)
100% fruit juice (servings/day)
Fish (servings/day)
Egg (servings/day)
Milk (servings/day)
Dairy products (servings/day)
Processed foods (servings/day)
+
+
+
+
+
+
+
+
+
+
+
+
Bhurosy et al. (2013), Mauri-
tius (102)
N= 189
Intervention ( n= 98)
Control ( n=91)
2 months
Calcium intake scores
Self efficacy
Knowledge scores
Physical activity level
Alcohol consumption
+
+
+
+
+
Abbreviations: FV: Fruit & vegetable; FVI: Fruit & Vegetable Intake; FFQ: Food Frequency Questionnaire; +: positive intervention effect; –: negative intervention effect
