Introduction The following paper will examine the effects of fruits and vegetables on cancer in young and middle-aged adults. Particular importance will be placed on examining antioxidants which are only found in fruits and vegetables and the effects they have on cancer prevention. Cancers may be caused in one of three ways, namely incorrect diet, genetic predisposition, and via the environment (Reddy et al. , 2003). At least 35% of all cancers worldwide are caused by an incorrect diet, and in the case of colon cancer, diet accounts for 80% of the cases (Reddy et al. , 2003).
Cancer is a disease in which disorder occurs in the normal processes of cell division, which are controlled by the genetic material (DNA) of the cell (Reddy et al. , 2003). One of the most important mechanisms contributing to cancer is considered to be oxidative damage to the DNA (Reddy et al. , 2003). Oxidative damage occurs as a result of oxidative stress. Burning fuel, like when you drive a car or burn wood, produces toxins. The word “burning” itself means reaction with oxygen. In your cells there are little “engines” called mitochondria, which burn food for energy.
In the process, free radicals are created. Free radicals react quickly with other compounds, trying to capture the electrons needed to gain stability (Kaur and Kapoor, 2001). When the molecule that has been attacked loses its electron it becomes a free radical itself, beginning a chain reaction which cascades resulting in destabilization and disintegration of the cell membranes or oxidation of other cellular components like proteins and DNA, finally resulting in the disruption of cells (Halliwell et al, 1995 as cited in Kaur and Kapoor, 2001).
This process is known as oxidative stress which causes reduced capabilities to combat ageing and serious illness, including cancer (Ames, 1983 as cited in Kaur and Kapoor, 2001). The only way to combat free radicals or oxidative stress is through the consumption of antioxidants. Antioxidants neutralize free radicals by donating one of their own electrons, ending the electron-stealing reaction and do not themselves become free radicals because they are stable in either form (Kaur and Kapoor, 2001).
Antioxidants are found in a wide variety of fruits and vegetables, plant extracts, tea, and herbs and spices (Reddy et al, 2003). Fruits and vegetables contain significant levels of biologically active components that impart health benefits beyond basic nutrition (Oomah and Mazza, 2000 as cited in Kaur and Kapoor, 2001). Consumption of fruits and vegetables has thus been associated with lower incidence and lower mortality rates caused by cancer in several human cohort and case-control studies for all common cancer types (Doll, 1990; Ames et al. , 1993; Dragsted et al. , 1993; Willet, 1994; as cited in Kaur and Kapoor, 2001).
Heber (2004) reports that the intake of 400-600 g per day of fruits and vegetables is associated with reduced incidence of many forms of cancer, and diets rich in plant foods are also associated with a reduced risk of many chronic diseases related to ageing. These foods contain phytochemicals that have anti-cancer and anti-inflammatory properties which confer many health benefits (Heber, 2004). It has been estimated that one-third of all cancer deaths in the United States could be avoided through dietary modification which includes an abundant intake of fruits and vegetables (Heber, 2004).
The present study was proposed to investigate the effects of fruits and vegetables on the levels of antioxidants of healthy young volunteers. Based on previous research on this topic it is plausible to predict that the administration of fruits and vegetables capsules to healthy young participants will result in beneficial effects on antioxidant levels over time. The conclusions of the present study will hopefully support the previously mentioned findings of Reddy et al (2003), Kaur and Kapoor (2001) as well as the conclusions of Heber (2004). Method Design.
For the present study a placebo controlled, repeated measures trial design was employed. The repeated measures experimental design was chosen because it best illustrates the change in antioxidant levels of each participant over time. The independent variable manipulated in this study was the fruit and vegetable capsules called Juice Plus, which was administered at 600 g per day as suggested in Heber (2004). A placebo group was dispensed inert capsules of similar appearance to the Juice Plus capsules. The dependent variable in this study was the level of antioxidants.
The aim of this study was to observe the change in antioxidant levels of the participants after a particular dosage of fruit and vegetable extracts were taken each day for eight week durations. Participants The present study consisted of two different groups of 70 volunteers for a total of 140 participants. The participants were obtained through a self-selecting sample of Saint Mary’s University students. The voluntary participants were recruited by posting a sign-up sheet in the psychology department of the university; as well the study was advertised in the school newspaper and also advertised on posters around the campus.
The 140 volunteers participating in this study consisted of 80 males and 60 females ranging in age from 18 – 28 years, with an average age of 23 years. Each participant was required to sign an informed consent form. All participants described themselves as relatively healthy and each testified that they were not taking any medication. Frequent cigarette and marijuana smokers as well as heavy alcohol and coffee drinkers were not permitted to take part in the study. The present study requires a significant amount of participation and cooperation on the part of the volunteers.
Therefore, ten points to be allocated to improve grades in various psychology courses were rewarded to each volunteer as incentive to participate. Additionally the participants were entered into four draws for $50 upon completion of the study. A further benefit to the participants was the possible increase in the protection of cancer development in the body, which would be valuable to them for the future. As a result of the voluntary nature of this experiment extraneous variables could only be controlled to a certain extent.
The participants were asked to take the proper number of capsules as directed each day, and further they were asked to refrain from any drug use as mentioned previously. It would have been advantageous to conduct a double blind experiment to rule out participant and experimenter expectations but due to the setting of the research it would have been very difficult to attain participants. Materials and Measures In order to conduct the present study a sufficient supply of Juice Plus capsules, as well as placebo capsules were needed.
A test of antioxidant levels for each of the two trials using a special antioxidant scanner that uses a blue laser to measure antioxidant levels in the skin tissue was also required. Informed consent forms, pencils, and paper were also needed to complete the research. As stated in the hypothesis, the purpose of this study is to demonstrate that Juice Plus will have a positive effect on cancer prevention in populations of healthy, young individuals. In order to measure improvements in antioxidant levels a test was prepared.
This test combined aspects of measuring the different levels of each of the major carotenoids (antioxidant agents) found in the fruits and vegetables in Juice Plus using a special antioxidant scanner. Procedure The research of the present study was conducted in a laboratory setting but much of the procedure of the study, namely the administration of the Juice Plus capsule, took place outside the laboratory, in the homes of the participants. After all the participants were recruited they were separated into two groups, a treatment group and a placebo group.
Each group consisted of 70 participants with 40 males and 30 females in each. At baseline all 140 participants took the same test to measure antioxidant levels. After the test, the treatment group was administered 600g of Juice Plus capsules and was given an eight week supply of the Juice Plus. The treatment group was instructed to take the 600g capsule per day at approximately the same time each day. The placebo group was administered the same number of capsules as the treatment group but these capsules contained an inert substance.
The placebo group was then given an eight week supply of the inert capsules and was given the same instructions as the treatment group. After the eight week experimental period all the participants returned to the laboratory to once again take a test to measure antioxidant levels. Results The hypothesis of this study predicted that the administration of Juice Plus capsules over time would result in beneficial effects on the prevention of cancer of the healthy young volunteers. The results of this repeated measure trial showed significant improvements in participant’s antioxidant levels from baseline to after treatment.
The mean score on the first antioxidant measure test, at baseline, was found to be 19998. 11 and the mean score on the second antioxidant measure test, after administration of 120 mg Juice Plus capsules per day for an 8-week period, was found to be 33526. 17. These results show a significant increase in mean scores from before and after treatment. The mean scores for the placebo group varied only marginally from the first session to the second. | |Test #1 |Test #2 | |N Valid |70 |70 | |Missing |0 |0 | |Mean |19998. 11 |33526. 17 | |Standard Deviation |5647.
22 |8698. 89 | Table 1: Represents mean and standard deviation values for the first and second test. [pic] Figure 1 In order to test the research hypothesis a one-tailed dependent/related samples t-test was performed. The dependent samples t-test found the change in mean scores to be significant. Discussion The results of this study show that administration of Juice Plus enhances antioxidant levels in healthy young adults. As expected the placebo group showed no significant sign of antioxidant level improvement between session one and session two.
However the group treated for eight weeks with the Juice Plus capsules showed a significant increase in antioxidant levels. The mean scores on the measurement of antioxidant levels for this treatment group increased considerably. The findings of this study support previous research on the cancer preventing effects of fruits and vegetables on healthy young adults. As well the conclusions of this study may help to support Kaur and Kapoor’s (2001) statement that fruits and vegetables act as antioxidants in the body by scavenging harmful free radicals which are implicated in most degenerative diseases.
This research design does have its limitations. As a result of the majority of the administration of Juice Plus capsules taking place outside of the laboratory, many extraneous variables may have affected the results of the study. It is possible or perhaps even probable that the participants may have forgotten to take the fruit and vegetable extract on various days or may have taken incorrect dosages of the extract. Additionally, because the study was not performed as a double-blind experiment, participant and experimenter expectancy may have been a confounding variable.
The top two causes of cancer are related to dietary habits and tobacco smoke, and as such, it is largely a preventable disease (Reddy et al. , 2003). Therefore, it would be interesting to see what effect fruits and vegetables have on the prevention of cancer and free radicals over time. A longitudinal study of a cohort beginning at a young age and proceeding throughout the cohort’s life would probably lead to a better understanding of the effects of fruits and vegetables (antioxidants) on cancer prevention over time.
Future research may hopefully reveal if this is the answer to the prevention of cancer and other degenerative diseases and put an end to the cancer epidemic our society faces today. Appendix A Confidentiality Statement/Participation Agreement I am aware that my participation in this research endeavor is strictly voluntary. I may withdraw participation at any time. I fully understand that the use of the data collected in this survey will be restricted to research purposes associated with this study. Participant confidentiality will be maintained at all times, my results will be corresponded to my assigned identification number only.
I hereby agree to the above conditions, confirming my participation in this survey process. Participant’s Signature_____________________________Date:___________________.
References Heber, D. (2004). Vegetables, fruits and phytoestrogens in the prevention of diseases. J Postgrad Med, 50, 145-149. Kaur, C. & Kapoor, H. C. (2001). Antioxidants in fruits and vegetables – the millenium’s health. International Journal of Food Science and Technology, 36, 703-725. Reddy, L. , Odhav, B. , Bhoola, K. D. (2003). Natural products for cancer prevention: a global perspective. Pharmacology & Therapeutics, 99, 1-13.