Effect of Nutrition Education on the Eating Habits of Undergraduates in South-West, Nigeria
Gloria O. Anetor,
Benjamin O. Ogundele
Oyediran E. Oyewole
To assess the effect of nutrition education on the eating habits that may predispose undergraduates to cancer, a quasi-experimental study was carried out in a representative sample of undergraduates aged 16 to 25 years in two Universities in South-west Nigeria. A sample of 436 participants (males and females) was randomly selected from both universities (1 control group; 1 experimental group). Participants eating habits was assessed before nutrition education intervention by having a focussed group discussion and responding to a 19-item self-developed food frequency scale (pretest). Nutrition education intervention was given to the experimental group for 8 weeks and the control group had a placebo. The effect of nutrition education on eating habits was measured immediately and 8 weeks after intervention using the pretest scale (posttest). Data analysis was employed using SPSS version 15; independent t-test, ANCOVA, using the pretest as the covariate to measure the effect of the intervention. Nutrition education significantly affected the eating habits of the participants (p<0.05). The experimental group performed better by contributing a higher mean score of 61.48 while the control group contributed a mean score of 56.64. The level of study significantly affected the eating habits of the participants with students in lower level of study performing better (p<0.05). Nutrition education positively modulated the eating habits of the participants. More students need to be exposed to nutrition education on eating habits because it appears to be a potent tool in forestalling the harmful effects of poor eating habits especially cancer.
November 10, 2011; Accepted: December 31, 2011;
Published: January 20, 2012
Cancer remains an important factor in the global burden of disease. The disease
arises principally as a consequence of individuals exposure to carcinogenic
agents in what they inhale, eat and drink or are exposed to in their personal
work environment. However, studies show that some people indulge in some eating
habits like excessive intake of salt, meat, fatty foods, low intake of fruits
vegetables, cigarette smoking, excessive intake of alcohol that make them more
susceptible than others to develop cancer, especially stomach cancer (Tsugane,
2005; National Cancer Institute (NCI), 2007; AICR,
2007; Anand et al., 2008). Over a decade
ago, the World Cancer Research Fund (WCRF) and the American Institute of Cancer
Research (AICR) predicted that one of three people globally will develop cancer
at some point in their lives and that there were over 10 million new cases of
cancer diagnosed each year (WCRF, 1997). In another report,
the World Health Organization (WHO) indicated that in many countries, more than
a quarter of deaths are attributable to malignant tumors. The report further
pointed out that cancer has emerged as a major health problem in developing
countries, matching its effects in industrialized nations.
Diet is one of the three factors (others being smoking, infections) that can
prevent one third of cancers and another third cured. Therefore, recommended
that the alarming rate of cancer spread will be prevented if these factors are
taken care of. This report was corroborated by other studies which confirmed
that thirty to forty percent of cancer cases have been linked to dietary choices
(Amorim-Cruz, 2000; Thiele et
al., 2004; Gunderson et al., 2004; Vairio
and Weiderpress, 2006; Anand et al., 2008;
National Cancer Institute (NCI), 2007).
Furthermore, Coren reported that cancers of the liver, stomach and oesophagus
were more common in the developing world than the developed countries and that
they are linked to consumption of carcinogenic preserved foods such as smoked
or salted food and parasitic infection of organs. He further reported that,
the most lethal cancers were lung, stomach and liver cancers (Coren,
Since, cancer is known to be a disease that can cause great suffering and claims many lives, the overall commitment of scientists and other professionals involved in disease prevention is to reduce the rates of cancer and other diseases, so that many people can enjoy quality life with good health until they eventually die in old age.
Previous studies carried out in Nigeria, pointed out that there is a dearth
of statistics (data) about cancer of the stomach and recommended that control
measures be introduced for its prevention despite the apparently low incidence
rates recorded probably to keep it in check (Oluwasola and
Ogunbiyi, 2003). This study may provide a rational scientific basis for
such an action or approach. In another report from Nigeria, it was reported
that 11.6% of patients who had Upper Gastro Intestinal Endoscopy (UGIE) conducted
for upper gastrointestinal diseases had stomach cancer at Obafemi Awolowo University
teaching hospital Ile-Ife, although no apparent cause was given for this (Agbakwuru
et al., 2006). This finding suggests that all hands must be on deck
to prevent stomach cancer which may actually be on the increase in Nigeria.
Thus, nutrition education is conceivably required as an important approach to
curb the rising incidence of cancers.
Nutrition education which is an integral part of health education is one of
the ways identified to prevent cancer spread especially diet related cancer
amongst which is stomach cancer. Nutrition education achieves this remit by
providing information on good nutritional habits which will lead to disease
prevention. Nutrition is therefore, a major modifiable determinant of chronic
diseases (Anderson et al., 2004; Prell
et al., 2005; Ajala, 2006; Arroyo
et al., 2006; Ozcelik et al., 2007;
Yahia et al., 2008). Dietary adjustment may not
only influence the present health but may determine whether or not an individual
develops diseases such as cancer and other chronic diseases later in life. The
successful reduction in the incidence of stomach cancer in some countries (America,
United Kingdom, Australia and Canada) that had a good statistics about the prevalence
of the disease has been achieved through dietary modifications (Young
and Wilson, 2002; Gunderson et al., 2004;
Mimi and Iris, 2004; National Cancer
Institute (NCI), 2007). In Nigeria, there appears to be no evidence of similar
effort to reduce stomach cancer through dietary efforts.
Many undergraduates are youths; youths encounter numerous health risks along
the path to adulthood, many of which affect quality of life and life expectancy.
Studies have revealed the vulnerability of youths to poor eating habits. They
are said to be in the habit of eating junks (Papadaki
and Scott, 2002). In a study, carried out in the United States, it was also
reported that university students consume a lot of fast food which is high in
fat and low intake of fruits and vegetables (Arroyo et
al., 2006; Kolodinsky et al., 2007; Yahia
et al., 2008). This type of eating habits has also been observed
among Nigerian undergraduates (Ajala, 2006).
It is perceived that, these poor eating habits arise from lack of knowledge
of the cumulative effects of their eating habits. This is of a grave concern
in Nigeria where there is an increase in fast food centres in its urban cities
(Akinwusi and Ogundele, 2005; Ajala,
2006). Most of these fast food restaurants sell junk food. The
junks consumed by most undergraduates contain dense calories which
are cancer promoting; and this poor eating habits may predispose them to diet
related cancers with stomach cancer being a prominent one of such cancers (Popkin,
1998; Rickert and SusaJay, 1996; Turconi
et al., 2008; Delisle et al., 2009).
Most undergraduates (youths) are most likely to be responsible for their diets
for the first time (away from home); therefore, they need guidance on how to
make informed choices (Satia et al., 2004). This
study therefore, examined the effect of nutrition education on the eating habits
of undergraduates in order to ensure continuous prevention and low incident
rate of stomach cancer in South-west Nigeria.
MATERIALS AND METHODS
Research protocol approval by ethics committee: The research protocol
was approved by the Ethics Committee of the Oyo State Ministry of Health Ibadan,
Nigeria and the reference number is AD 13/479/110. A written consent was sought
from the participants in this study.
The nutrition education intervention programme in this study adopted a quasi-experimental design of the pretest-posttest method. The study was carried out between November 2009 and March 2010. The participants of this study were made up of undergraduates from two of the three first generation universities in south-west, Nigeria. One of the universities was randomly selected as control group and the other as the experimental group. Four hundred and thirty-six undergraduates (males and females) between 16 and 25 years of age were initially randomly selected for the study with a later attrition of 8.7%; therefore, a total of 398 finally participated in the study. The sampling procedure was as follows:
The faculties in each selected university were stratified into two namely: arts and science. Using simple random sampling with replacement, 50% of faculties in each stratum were selected. Then, 25% of the departments in the selected faculties were also randomly selected. Then, proportionate sampling procedure was used to select 5% of the students from each selected department; the participants in the selected departments were stratified into three groups using their levels of study (100-200; 300-400; 500-600); employing systematic random sampling technique; 5% the participants were selected from these strata. Males and females with age ranging from 16 and 25 years participated in the study. With this procedure two hundred and fifty-nine participants were selected from the experimental group while one hundred and seventy-seven participants were selected from the control group, this made a total of four hundred and thirty-six participants from both universities. However, three hundred and ninety-eight participants (91.3%) completed the study (with an attrition rate of 8.7%).
The nutrition education intervention: Before the nutrition education
intervention, a Focus Group Discussion (FGD) was carried out to establish baseline
information that indicated areas of attention that had to be addressed during
the course of intervention. The focus group discussion was conducted in four
sessions in each University as follows: males: 100-300 level; 400-600 level;
females: 100-300 level; 400-600 level. Each session comprised of 8-11 participants
that were selected using purposive random sampling technique. The chief Investigator
was the moderator of the FGDs, assisted by a secretary and a timekeeper/observer.
Each discussion session took place in the students halls of residence
for duration of between 45-60 min. All the discussion sessions were recorded
and transcribed subsequently.
Then was the development of the questionnaire used to collect the required information for the pretest and posttest in the study. The questionnaire was self-developed, self-administered and the content of the questionnaire was guided by the study objectives and review of literature on eating habits that may predispose to stomach cancer. The questionnaire sought information on the eating habits of the participants (QEHA). There were five items on the demographic attributes of the participants and nineteen items measuring the eating habits of the participants. The questions were based on a five-point Likert-scale type. The participants answered the questions in this section or provided comments by answering as follows never (not at all), rarely (at least once a month), occasionally (at least once a week), often (four times a week) and very often (at least once a day). Each item had a score of 1-5 marks (negative to positive) and the total mark obtainable was 95 marks. The participants were then rated as follows: 0-35 = poor, 36-55 = fair, 56-75 = good and 76-95 = very good. The psychometric properties of the questionnaire were determined by carrying out item analysis of each question and Cronbach Alpha was used to determine the reliability coefficient and this yielded 0.82.
Before the training on nutrition education of the experimental group, the questionnaire was administered and same was administered immediately after the intervention and repeated eight weeks after the intervention to ascertain the actual effect of the intervention. The intervention was teaching sessions for eight weeks and the lectures held one hour weekly. The control group also had the questionnaire administered before and after giving them a placebo treatment on HIV/AIDS stigmatization which also lasted eight weeks. Ten research assistants who were undergraduates were used for the study and on the spot collection of the questionnaires were ensured.
The nutrition education lectures on eating habits predisposing to cancer were developed and included: introduction on the objective of the study, a brief anatomy of the stomach, aetiology of cancer and specific causes of stomach cancer, an overview of cancer and diet, specific dietary factors of stomach cancer, preparing a meal using food pyramid, importance of nutrition facts and food labels, healthy feeding in relation to stomach cancer and unhealthy feeding in relation to stomach cancer. The intervention programme took place for one hour weekly and lasted for eight weeks. An initial pretest was administered to the participants, followed by the nutrition education; then posttest was given which was the same as the pretest. The control group had a placebo lecture on HIV/AIDS stigmatization.
Data analysis: All data collected were coded and entered into computer for analysis, using Statistical Package for Social Sciences (SPSS) programme package version 15. Descriptive statistics of frequency distribution and percentages were used to describe the demographic data, independent t-test and analysis of covariance (ANCOVA) were used for the variables studied; Multiple Classification Analysis (MCA) was utilized to determine the direction and strength of the intervention in the experimental and control groups. The decision criterion for accepting or rejecting all the variables of the study was set at 0.05 level of significance (p<0.05).
In this study, 398 participants (8.7% attrition) participated in the training programme on nutrition education targeted in ameliorating the eating habits that may predispose undergraduates to stomach cancer.
Characteristics of the sample: Table 1 shows the demographic characteristics of the participants. The total number of participants in the experimental group was 225 which represented 56.5% of the participants and the number of participants in the control group was 173 which represented 43.5% of the participants. Gender distribution shows that the total number of male participants was 203 (106 in the control and 97 in the experimental); which is 51.0% of the participants; and the female participants were 195 (67 in the control and 128 in the experimental) which is 49.0% of the total participants. The age distribution in the two age groups used for the study shows that 127 (56 in the control group and 71 in the experimental group) of the participants were between 16 and 20 years of age (31.9%) while 271 (117 in the control group and 154 in the experimental group) of the participants were between 21 and 25 years of age (68.1%). The distribution of the participants by the level of study shows that 189 participants (68 in the control group and 121 in the experimental group) of the total participants were in the group of 100-200 level (47.5%), 178 participants (80 in the control group and 98 in the experimental group) of the total participants were in the group of 300-400 level (44.7%) while 31 participants (25 in the control group and 6 in the experimental group) were in the group of 500-600 level (7.8%).
|| Demographic characteristics of the participants
After the intervention, the description of the participants scores assessed
from the eating habits scale was as follows:
||15% of the participants
||30% of the participants
||25% of the participants
||50% of the participants
||50% of the participants
||15% of the participants
||10% of the participants
||5% of the participants
The effect of nutrition education intervention on the eating habits of the
participants was shown in Table 2 below after analysing with
ANCOVA. There was a significant difference (p<0.05) in the eating habits
after the intervention. The multiple classification analysis in Table
3 further shows the contribution of the participants to the significant
difference and the percentage contribution of the intervention. The experimental
group contributed more to the significant results with a mean score of 61.48
than the control group with a mean score of 56.64, respectively (derived by
adding the unadjusted variation to the grand mean). The coefficient of determination
in R2 = 0.086. This implies that 8.6% of the significant effect was
accounted for by the intervention.
Table 4 shows the analysis of the level of study on the eating habits of the participants. The level of study in the participants significantly affected their eating habits (F(3.394) = 4.768 p = 0.009<0.05).
In showing the direction of how the eating habits is affected by the level of study, Table 5 shows that, 100-200 level had the mean of 60.70; 300-400 level had the mean of 58.29 and 500-600 level had the mean of 57.52. The coefficient of determination which is presented in R2 = 0.024. Therefore, 2.4% of the difference was accounted for by the intervention.
|| Effect of intervention on the eating habits of the participants
|| Analysis showing the direction of the eating habits of the
participants grand mean = 59.37
|Multiple Classification Analysis (MCA)
|| Analysis of level of study on the eating habits of the participants
|| Analysis showing the direction of level of study on eating
habits grand mean = 59.37
||Analysis of eating habits by gender and age
Table 6 shows the result of examining the effect of age and gender on the eating habits of the participants. Age and gender did not significantly affect the eating habits of the participants (p>0.05).
Eating habits have been implicated in many chronic diseases including stomach
cancer. In response to the mounting evidence that eating habits can be modulated
with nutrition education (Guthie and Frazo, 2002; Key
et al., 2002; Meydani, 2002; Greenwald,
2005; Kolodinsky et al., 2007; Whitney
and Rolfes, 2008). This study put up an 8 week intervention programme on
the eating habits of undergraduates aimed at modulating the eating habits that
may predispose undergraduates to stomach cancer in south-west, Nigeria.
In this study, the eating habits scaled examined after the nutrition education
intervention shows that 50% of people in the experimental group had good eating
habits while only 15% of people in the control group had good eating habits.
In the ANCOVA analysis done, nutrition education intervention significantly
affected the eating habits of the participants (p≤0.05). The direction of
significance as shown in the multiple classification analysis indicates that
8.6% of the result was accounted for by the nutrition education intervention
given. The experimental group exhibited a higher mean score of 61.50 while the
control group demonstrated a mean score of 56.64. This implies that the experimental
group has demonstrated a more positive change in their perception of eating
habits by contributing a higher mean to the significant result than the control
group. This result implies that the nutrition education given to the experimental
group has been effective. The experimental group performed better than the control
group and this may be attributable to the education they have received. In the
FGDs had earlier with the participants, they were more interested in placing
taste preference to the health benefits of the food they consumed. The nutrition
education appears to have corrected this belief in the participants. The finding
in this study confirms the assertion of other studies about the efficacy of
nutrition education intervention as a potent tool in bringing about behaviour
change (Sorensen et al., 1999; Prentice
and Paul, 2000; Oladepo, 2002; Ngwu,
2005; Ajala, 2006; Asinobi and
Onimawo, 2007). The nutrition education has been able to improve the knowledge
of the undergraduates such that they were able to make informed choices in their
eating habits after the intervention.
The level of study of the participants significantly affected their eating
habits. The students in the lower level of study performed better than students
in higher levels of study as shown by higher mean scores of the students (Table
5). It can be implied from this result that it is a lot easier to impact
changes or new knowledge in the junior ones than the senior ones. It is also
noteworthy to mention that the finding in this study confirms the findings where
it was reported that lower grades students had better eating habits than students
in higher grades in similar studies (Westenhoefer, 2005;
Driskell et al., 2005).
On the other hand, age and gender did not significantly affect the eating habits
of the participants in this study and this finding appears to be at variance
with other findings that reported that age and gender significantly affected
the eating habits of college students (St-Onge et al.,
2003; Westenhoefer, 2005). It may be assumed that
the age limit of the participants in this study is probably not wide enough
to bring about a significant difference.
In this study, eating habits have been positively modulated by nutrition education. The students in lower the lower level appeared to have been more favourably disposed to the nutrition education intervention given. It is concluded that nutrition education is a potent tool that can improve and modulate the eating habits of undergraduates; therefore can prevent the dietary risk of stomach cancer and other chronic diseases. It is thus advisable that more undergraduates especially from lower levels of study should undergo nutrition training on eating habits as change may be relatively easier to achieve at this stage of study.
The authors are indebted to the advice and support of Dr John Anetor of the University of Ibadan, Dr Abiodun O. Ajose of Obafemi Awolowo University Ile-Ife, the analyst Mr. Ayo Odewunmi, the research assistants and all the students who participated in this study from the University of Ibadan and Obafemi Awolowo University, Ile-Ife.
AICR, 2007. Foods that fight cancer. American Institute for Cancer Research, USA
Agbakwuru, E.A., A.O. Fatusi, D.A. Ndubula, O.I. Alatise, O.A. Arigbabu and D.O. Akinola, 2006. Pattern and validity of clinical diagnosis of upper gastrointestinal disease in South-West Nigeria. Afr. Health Sci., 6: 98-102.
Ajala, J.A., 2006. Understanding Food and Nutrition: Eat for Health! You are What You Eat. MayBest Publications, Akinwusi, Ibadan, ISBN: 9789783723351, Pages: 162.
Akinwusi, A.T. and B.O. Ogundele, 2005. Influence of economy, society and personal beliefs on nutritional habits. Nig. Sch Health, 17: 143-149.
Amorim Cruz, J.A., 2000. Dietary habits and nutritional status in adolescents over Europe-Southern Europe. Eur. J. Clin. Nutri., 54: S29-S35.
Direct Link |
Anand, P., A.B. Kunnumakkara, C. Sundaram, K.B. Harikumar and S.T. Tharakan et al., 2008. Cancer is preventable disease that requires major life style changes. Pharm. Res., 25: 2097-2116.
Anderson, A.S., L.E. Porteous, G. Foster, C. Higgins and M. Stead et al., 2004. The impact of a school-based nutrition education intervention on dietary intake and cognitive and attitudinal variables relating to fruits and vegetables. J. Public Health Nutri., 8: 650-656.
PubMed | Direct Link |
Arroyo, I.M., P.A.M. Rocandio, A.L. Ansotegui, A.E. Pasual, B.I. Salces and O.E. Rebato, 2006. Diet quality, overweight and obesity in universities' students. J. Hosp. Nutri., 21: 673-679.
Asinobi, C.O. and A.I. Onimawo, 2007. Infection and prevalence of malnutrition in adolescent girls in low socio-economic rural community of Ohaji/Egbema local government area of Imo state, Nigeria. Nig. J. Nutri. Sci., 28: 105-114.
Coren, M., 2005. Cancer no longer rare in poor countries. Global Health Concil
Delisle, H.F., J. Vioque and A. Gil, 2009. Dietary patterns and quality in West-Africa immigrants in Madrid. Nutr. J., 8: 3-3.
CrossRef | Direct Link |
Driskell, J., Y.N. Kim and K. Goebel, 2005. Few differences found in the typical eating and physical activity habits of lower-level and upper-level university students. J. Am. Diet. Assoc., 105: 798-801.
PubMed | Direct Link |
Greenwald, P., 2005. The future of cancer prevention. Seminars Oncol. Nurs., 21: 296-298.
PubMed | Direct Link |
Gunderson, L.L., J.H. Donohue and S.R. Alberts, 2004. Cancer of the Stomach. In: Clinical Oncology. Abellof, M.D, J.O. Armitage, J.E. Niederhuber, M.B. Kastan and W.G. McKena (Eds.). Elsevier Churchill Livingstone, Philadelphia, USA., pp: 380-415.
Guthrie, J., B.H. Lin and E. Frazao, 2002. Role of food prepared away from home in American diet, 1977-78 versus 1994-96: Changes and consequences. J. Nutr. Educ. Behav., 34: 140-150.
PubMed | Direct Link |
Key, T.J., N.E. Allen, E.A. Spencer and R.C. Travis, 2002. The effect of diet on risk of cancer. Lancet, 360: 861-868.
Kolodinsky, J., J.R. Harvey-Berino, L. Berlin, P.K. Johnson and T.W. Reynolds, 2007. Knowledge of current dietary guidelines and food choice by college students: Better eaters have higher knowledge of dietary guidance. J. Am. Diet Assoc., 107: 1409-1413.
Direct Link |
Meydani, M., 2002. Nutrition interventions in aging and age-associated disease. Proc. Nutr. Soc., 61: 165-171.
Mimi, M.Y.T. and F.F.B. Iris, 2004. Diet and health: nursing perspective for the health of our aging populations. Nurs. Health Sci., 6: 309-314.
CrossRef | PubMed |
National Cancer Institute (NCI), 2007. What you need to know about stomach cancer. Retrieved December 5, from http://www.cancer.gov/cancertopics/wyntk/stomach
Ngwu, E.K., 2005. Characteristics of patients receiving health education and dietary counseling in a Nigerian Teaching Hospital. Nig. J. Nutri. Sci., 26: 43-49.
Oladepo, O., 2002. Public Health Education. In: Health Education and Health Promotion, Ademuwagun, Z.A., J.A. Ajala, E.A. Oke, O.A. Moronkola and A.S.J. Ibadan (Eds.). Royal People Nigeria Ltd., Nigeria, pp: 114-121.
Oluwasola, A.O. and J.O. Ogunbiyi, 2003. Gastric cancer: Aetiological, clinicopathological and management patterns in Nigeria. Niger. J. Med., 12: 177-186.
Ozcelik, A.O., M.S. Surucuoglu and L.S. Akan, 2007. Survey on the nutrition knowledge level of Turkish physicians: Ankara as a sample. Pak. J. Nutr., 6: 538-542.
CrossRef | Direct Link |
Papadaki, A. and J.A. Scott, 2002. The impact on eating habits of temporary translocation from a Mediterranean to a Northern European environment. Eur. J. Clin. Nutr., 56: 455-467.
Direct Link |
Popkin, B.M., 1998. The nutrition transition and its health implications in lower-income countries. Public Health Nutr., 1: 5-21.
Prell, H.C., M.C. Berg, L.M. Jonsson and L. Lissner, 2005. A school-based intervention to promote dietary change. J. Adolesc Health, 36: 529-529.
Prentice, A.M. and A.A. Paul, 2000. Fat and energy needs of children in developing countries. Am. J. Clin. Nutr., 72: 1253S-1265S.
Rickert, V.I. and M. SusaJay, 1996. Behavior Change and Compliance: the Dietician as Counselor. In: Adolescent Nutrition Assessment and Management, Rickert, V.I. (Ed.). Chapman and Hall, New York, pp: 123-132.
Satia, J.A., J.A. Galanko and A.M. Siega-Riz, 2004. Eating at fast food restaurants is associated with dietary intake, demographic, psychosocial and behavioural factors among African Americans in North Carolina. Public Health Nut., 7: 1089-1096.
Direct Link |
Sorensen, G.A., K. Stoddard, N. Peterson, N. Cohen and M.K. Hunt et al., 1999. Increasing fruit and vegetable consumption through worksites and families in the treatwell 5-a-day study. Am. J. Public Health, 89: 54-60.
Direct Link |
St-Onge, M.P., K. Keller and S. Heymsfield, 2003. Changes in Childhood Food Consumption Patterns: A cause for concern in light of increasing body weights. Am. J. Clin. Nutr., 78: 1068-1073.
Direct Link |
Thiele, S., G.B.M. Mensink and R. Beitz, 2004. Determinants of diet quality. Public Health Nut., 7: 29-37.
Direct Link |
Tsugane, S., 2005. Salt, salted food intake and risk of gastric cancer: Epidemiologic evidence. Cancer Sci., 96: 1-6.
Direct Link |
Turconi, G., M. Guarcello, L. Maccarini, F. Cignoli, S. Setti, R. Bazzano and C. Roggi, 2008. Eating habits and behaviours, physical activity, nutritional and food safety knowledge and beliefs in an adolescent Italian population. J. Am. Coll. Nut., 27: 31-43.
Vairio, H. and E. Weiderpress, 2006. Fruits and vegetable in cancer prevention. Nut. Cancer, 54: 111-142.
WCRF., 1997. Food, nutrition and prevention of cancer: A global perspective. WCRF/AICR. World Cancer Research Fund, World Health Organization (WHO), American Institute for Cancer Research (AICR)
Westenhoefer, J., 2005. Age and gender dependent profile of food choice. Forum Nut., 57: 44-51.
Whitney, E. and S.R. Rolfes, 2008. Understanding Nutrition. 11th Edn., Thompson Learning Inc., USA.
Yahia, N., A. Achkar, A. Abdallah and S. Rizk, 2008. Eating habits and obesity among Lebanese university students. Nutr. J., Vol. 7. 10.1186/1475-2891-7-32
Young, R.C. and C.M. Wilson, 2002. Cancer prevention: Past present and future. Clin. Cancer Res., 8: 11-16.