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Background DNA is constantly exposed to reactive oxygen species (ROS), spontaneously arising during the normal oxygen metabolism. ROS may result in temporary as well as permanent modifications in various cellular components such as lipids, proteins and DNA, which may have deleterious consequences. Demonstrating that a dietary supplementation of antioxidants can reduce oxidative DNA damage may provide evidence for the value of such supplementation in prevention of cancer and age related diseases. Findings The present study was conducted to address whether tomato juice protects against ROS induced by extensive physical exercise in untrained individuals. As a marker of oxidative stress, serum levels of 8-oxodG were monitored using a modified ELISA. An intervention was performed involving 15 untrained healthy subjects who performed a 20 min physical exercise at 80% of maximum pulse using an ergometer bicycle. Blood samples were taken before and one hour after the exercise. The procedure was repeated after 5 weeks with a daily intake of 150 ml tomato juice and followed by a 5 weeks wash-out period and another 5 weeks with a daily intake of tomato juice. The results indicated that a daily intake of tomato juice, equal to 15 mg lycopene per day, for 5 weeks significantly reduced the serum levels of 8-oxodG after an extensive physical exercise. Conclusion These data strongly suggest that tomato juice has a potential antioxidant effect and may reduce the elevated level of ROS induced by oxidative stress.
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S H O R T R E P O R T Open Access
Tomato juice intake suppressed serum
concentration of 8-oxodG after extensive
physical activity
Mats Harms-Ringdahl, Dag Jenssen and Siamak Haghdoost
Background: DNA is constantly exposed to reactive oxygen species (ROS), spontaneously arising during the normal
oxygen metabolism. ROS may result in temporary as well as permanent modifications in various cellular
components such as lipids, proteins and DNA, which may have deleterious consequences. Demonstrating that a
dietary supplementation of antioxidants can reduce oxidative DNA damage may provide evidence for the value of
such supplementation in prevention of cancer and age related diseases.
Findings: The present study was conducted to address whether tomato juice protects against ROS induced by
extensive physical exercise in untrained individuals. As a marker of oxidative stress, serum levels of 8-oxodG were
monitored using a modified ELISA. An intervention was performed involving 15 untrained healthy subjects who
performed a 20 min physical exercise at 80% of maximum pulse using an ergometer bicycle. Blood samples were
taken before and one hour after the exercise. The procedure was repeated after 5 weeks with a daily intake of
150 ml tomato juice and followed by a 5 weeks wash-out period and another 5 weeks with a daily intake of
tomato juice. The results indicated that a daily intake of tomato juice, equal to 15 mg lycopene per day, for
5 weeks significantly reduced the serum levels of 8-oxodG after an extensive physical exercise.
Conclusion: These data strongly suggest that tomato juice has a potential antioxidant effect and may reduce the
elevated level of ROS induced by oxidative stress.
Keywords: Reactive oxygen species, ROS, Free radicals, Exercise,Lycopene,Tomatojuice,Lifestyle,ELISA,
hMTH1, 8-oxo-dG
It has been suggested that dietary antioxidants reduce the
level of oxidative DNA damage induced by reactive oxy-
gen species. However, there are limited in vivo studies
which support this hypothesis as a number of epidemio-
logical studies showed no such effect following dietary
supplementation with carotenoids, vitamin C, or E [1,2].
Urinary concentration of 8-hydroxy-2-deoxyguanosine
(8-oxodG, a base damage formed by reactive oxygen spe-
cies) has been used as a non-invasive biomarker of oxida-
tive DNA base damage in a number of studies [3,4].
Reactive oxygen species (ROS) have been suggested to
play an important role in mutagenesis, carcinogenesis,
and aging processes. ROS can react with different cellu-
lar components e.g., proteins, lipids and nucleic acids,
and give rise to chemical modifications. Under normal
conditions cellular antioxidant enzymes and other anti-
oxidants in the cell detoxify elevated levels of ROS and
minimize damage to intracellular components. However,
under extensive physiological activity ATP consumption
will increase followed by increased oxygen consumption
and, as a consequence, the production of ROS will
increase [5]. Healthy and/or well-trained persons and
vegetarians seem to have increased protection against
ROS-induced damages [6]. It suggests that regular phys-
ical exercise [7] and a diet rich in antioxidant [8] may have
a protective effect towards ROS-induced damage, in par-
ticular DNA base damage. One of the frequently studied
DNA base damages is 8-oxodG. Highly effective repair
mechanisms are operating both on DNA (e.g., hOGG1)
* Correspondence:
Centre for Radiation Protection Research (CRPR), Department of Genetics,
Microbiology and Toxicology, Stockholm University, SE-106 91, Stockholm,
© 2012 Harms-Ringdahl et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the
Creative Commons Attribution License (, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.
Harms-Ringdahl et al. Nutrition Journal 2012, 11:29
and the nucleotide pool (hMTH1) to remove 8-oxodG/8-
oxodGTP from the cell [9,10]. Previously, we have shown
that extracellular 8-oxodG originates from the nucleotide
pool and may serve as a sensitive marker of oxidative
stress [11]. We have developed an ELISA method that
allows the determination of the very low concentrations of
8-oxodG present in human blood serum [11-13].
In the present study we aimed to investigate the pro-
tective effect of tomato juice intake towards ROS
induced by 20 min of extensive physical exercise. A
novel finding in the present intervention study was that
the level of 8-oxodG in human blood serum was
increased significantly after 20 min acute physical activ-
ity possibly caused by an increase of the intracellular
ROS level. No increase was observed when individuals
had been drinking 150 ml tomato juice per day during a
period of 5 weeks suggesting that the intracellular nu-
cleic acids and, in particular, the nucleotide pool were
unaffected and well protected from the deleterious effect
of ROS. The intervention study support the hypothesis
that antioxidants (e.g. lycopene) supplied from tomato
juice may protect against oxidative stress induced by ex-
tensive physical exercise.
Materials and methods
In this study 15 healthy and untrained donors (Table 1)
were asked to drink 150 ml tomato juice per day in 2 peri-
ods of 5 weeks each as follows: 5 weeks with tomato juice,
5 weeks without tomato juice and 5 weeks with tomato
juice. Blood samples were collected before and after start of
each period during the intervention study. At the day for
blood collection, the individuals were asked to do 20 min
physical exercise with 80% max pulse using an ergometer
bicycle. To calculate the individual maximum pulse, the fol-
lowing generally accepted formula was used: 220 - age =
maximum pulse. Blood samples were collected before and
after exercise. The serum level of 8-oxodG was analyzed as
a marker of oxidative stress. Of note, this intervention study
was designed according to recommendations which have
been published by Loft and co-workers [14]. The study was
performed in accordance with the ethical standards and
approved by the Swedish Ethical Committee at the
Karolinska University Hospital (Dnr 03621).
Analysis of 8-oxodG in blood serum
Just before and one hour after each training session
(20 min cycling), blood samples were collected in tubes
Table 1 Main characteristics of the donors
Donors Age Sex Smoking Vegetarian Vitamins Background diseases
1 30 F No no no no
2 28 M No no no no
3 35 M No no yes no
4 28 F No no no no
5 29 F No no yes no
6 46 M No no no no
7 29 M No no no no
8 24 F No no yes no
9 27 M No no yes no
10 25 F No no no no
11 25 F 3-5 cig/day no no no
12 27 M No no no no
13 43 F No no no no
14 38 M No no no no
15 24 M No no no no
Table 2 Concentration of 8-oxodG before and after 20 min physical activity (mean ± SE) in blood serum after periods
with and without tomato juice intake
without TJ 5 weeks with TJ 5 weeks without TJ 5 weeks with TJ
8-oxodG ng/ml A1 A2 B1 B2 C1 C2 D1 D2
0.52±0.11 0.74±.0.14 0.56±0.13 0.46±0.06 0.45±0.08 0.83±0.16 0.31±0.06 0.39±0.06
A1, A2, B1 and B2; n=15. For C1 and C2; n=11 while for D1 and D2; n=9.
TJ: tomato juice.
Samples A1, B1, C1 and D1: the level of 8-oxodG before 20 min physical activity.
Samples: A2, B2, C2 and D2: the level of 8-oxodG 1h after 20 min physical activity.
Harms-Ringdahl et al. Nutrition Journal 2012, 11:29 Page 2 of 5
without anticoagulant. After complete coagulation of the
blood samples, the blood serum was isolated. 8-OxodG
concentration of blood serum was measured using ELISA
as described previously [11,15]. The ELISA kit was pro-
vided by Health Biomarkers Sweden AB. Briefly, 1 ml
blood serum was purified using a C18 solid phase extrac-
tion column (Varian, CA) according to a previously
published method [16]. This step is necessary to remove
products other than 8-oxodG which could cross-react
with the monoclonal antibody used in the kit. A standard
curve for 8-oxodG (0.05 - 10 ng/ml) was established for
each plate covering the range of 8-oxodG in the samples.
One sample in each experiment was mixed with 1 ng
8-oxodG before purification which served as internal
standard. Validation of the modified ELISA method
was performed by HPLC-EC (r
:0.87,p<0.05) [15].
Comparisons between the ELISA and the HPLC-EC
methods showed a linear correlation at the concentration
range found in the human blood serum [15]. There was
no correlation between ELISA and HPLC-EC when unfil-
tered samples were used.
Determination of the lycopene content in tomato
The lycopene content in tomato juice was determined
spectrophotometrically essentially as described in refer-
ence by Fish et al. [17]. The concentration of lycopene
was calculated using the molar extinction coefficient of
lycopene in hexane (17.2 × 10
Statistical method
Students t-test was used for testing statistical signifi-
cance for serum levels of 8-oxodG. A p-value below 0.05
was deemed as significant.
8-oxodG (ng/ml)
Figure 1 Mean values of the individual changes in 8-oxodG serum concentrations (values before exercise are subtracted from values
after exercise) after 20 minutes of exercise. White bars show the changes when exercise was performed without previous tomato juice
supplementation. Dotted bars show the values after five weeks of lycopene supplementation. For bars A2-A1 and B2-B1 n = 15 and for C2-C1
n = 11 while for D2-D1 n = 9.
8-oxodG (ng/ml)
Figure 2 Shows mean values of individual changes of 8-oxodG level after periods without(mean of A and C periods; n =26) and after
periods with tomato juice intake (mean of B and D values; n = 24) before and after exercise respectively. Bars show means ± SE.
Harms-Ringdahl et al. Nutrition Journal 2012, 11:29 Page 3 of 5
The participants were asked to have a daily intake of
150 ml tomato juice (containing 0.1 mg lycopene per ml
juice) for 35 days in 2 interventions with a wash-out
period between these periods. The main characteristics
of the donors are presented in Table 1. Blood samples
were collected day 0 (period A), day 35 (end of period
B), day 70 (end of period C; washout) and day 105 (end
of period D). Two blood samples were taken at each oc-
casion, one before and the second 60 minutes after the
20 min physical exercise. The serum level of each par-
ticipant was compared to his/her own control value.
Thus, each participant served as his/her own control.
Table 2 shows the concentrations of 8-oxodG in serum
at the different sampling times during the intervention
study. The background levels (before exercise) of 8-oxodG
did not deviate significantly during the interventions.
As shown in Table 2, 20 min extensive physical activity
increased the level of 8-oxodG in serum above the back-
ground level by an average of 42% (from 0.52 up to
0.74 ng/ml). In contrast, following 5 weeks (B) intake of
150 ml tomato juice (corresponding to a daily intake of
15 mg lycopene) the levels of 8-oxodG remained essen-
tially unchanged after compared to before the exercise.
After the 5-week washout period (C), the level of 8-
oxodG increased again (84%) after exercise in average
from 0.45 up to 0.83 ng/ml. After the second period of
tomato juice intake (D), the levels of 8-oxodG after ex-
ercise were almost the same as before the exercise (from
0.31 up to 0.39 ng/ml).The results are summarized and
presented in Table 2 and in Figures 1 and 2.
The data in Figure 2 are the average changes of 8-
oxodG induced by physical activity (the concentration of
8-oxodG before exercise is subtracted from the concen-
tration after activity exercise) without tomato juice in-
take (periods A and C) and with tomato juice intake
(periods B and D).
As shown in Table 1, four subjects took vitamin sup-
plementation. Also when these subjects were excluded
from the statistical analysis, the effects of tomato juice
intake remained significant.
Based on the results from this intervention study it is con-
cluded that 8-oxodG is significantly increased in blood
serum of 15 healthy donors after an acute physical exer-
cise, suggesting that there is a positive correlation between
8-oxodG in serum and the intracellular ROS production.
The study also demonstrates that 150 ml tomato juice in-
take (15 mg lycopene) per day significantly protects the
nucleotide pool from ROS produced in response to exten-
sive physical activity. The proposed explanation for the
observed results is that ROS induced by extensive physical
activity react with intracellular dNTP and give rise to
production of 8-oxodGTP. 8-OxodGTP is excreted from
the intra- to the extra-cellular matrix by the action of
hMTH1 protein [18] to inhibit its incorporation into the
DNA. Lower levels of 8-oxodG in serum during tomato
juice intake show that tomato juice intake protects dNTP
from ROS induced modification.
It is important to mention that beside lycopene toma-
toes also contain vitamin C, tocopherols and polyphe-
nols [19]. It has been shown that among all antioxidants
(in particular carotenoids) present in tomato juice, lyco-
pene is the most abundant and stable during industrial
food processing [19]. Vitamin C and tocopherols in fresh
tomato are destroyed by heating during food processing.
Not much is known about the polyphenols in tomato
juice [19]. Therefore, we believe that the antioxidant ac-
tivity of tomato juice is primarily due to its content of
It might be hypothesized that long term intake of tomato
juice may reduce oxidative stress levels in patients with
enhanced level of oxidative stress, for example, patients
with diabetes, cardiovascular diseases or inflammation. A
study is in progress to test the hypothesis on patients with
diabetes using the experimental model system described
with 8-oxodG as biomarker.
Competing interests
Authors have no competing interests.
This work was supported by the Commission of European Union (Grant
agreement 245030). We would like to thank associated professor Siv
Osterman Golkar for valuable comments and discussions. We also thank
Christofer Andersson for his contribution and all the volunteers who
participated in this project. Finally we thank Kiviks Musteri AB for providing
the tomato juice.
SH served as Principal Investigator and contributed to design of the
experiment, manuscript preparation and determination of 8-oxodG in
human blood. MH-R contributed to writing the manuscript, procurement of
external funding and study design. DJ contributed to study design,
manuscript preparation and data presentation. All authors read and
approved the manuscript.
Received: 2 November 2011 Accepted: 9 April 2012
Published: 2 May 2012
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Cite this article as: Harms-Ringdahl et al.:Tomato juice intake
suppressed serum concentration of 8-oxodG after extensive
physical activity. Nutrition Journal 2012 11:29.
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Harms-Ringdahl et al. Nutrition Journal 2012, 11:29 Page 5 of 5
... Tomato products and supplementation with their constituents are suggested to reduce muscle damage caused during anaerobic exercise as well as reduce oxidative stress during aerobic exercise, as shown by Harms-Ringdahl et al. [320]. In their study, 15 healthy and untrained participants engaged in 20 min of aerobic exercise on a bicycle after receiving 150 mL of tomato juice for 5 weeks, followed by 5 weeks without tomato juice, and for the final intervention they received tomato juice for another 5 weeks [320]. ...
... Tomato products and supplementation with their constituents are suggested to reduce muscle damage caused during anaerobic exercise as well as reduce oxidative stress during aerobic exercise, as shown by Harms-Ringdahl et al. [320]. In their study, 15 healthy and untrained participants engaged in 20 min of aerobic exercise on a bicycle after receiving 150 mL of tomato juice for 5 weeks, followed by 5 weeks without tomato juice, and for the final intervention they received tomato juice for another 5 weeks [320]. The blood samples were collected before and after each intervention, and results showed that tomato juice intake significantly suppressed 8-oxodG (a marker of oxidative damage) levels produced with the physical activity [320]. ...
... In their study, 15 healthy and untrained participants engaged in 20 min of aerobic exercise on a bicycle after receiving 150 mL of tomato juice for 5 weeks, followed by 5 weeks without tomato juice, and for the final intervention they received tomato juice for another 5 weeks [320]. The blood samples were collected before and after each intervention, and results showed that tomato juice intake significantly suppressed 8-oxodG (a marker of oxidative damage) levels produced with the physical activity [320]. Therefore, there is evidence that tomato products can reduce oxidative stress and muscle damage caused by physical exertion and can be considered as a workout drink [320]. ...
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This review outlines the health benefits associated with the regular consumption of tomatoes and tomato products. The first section provides a detailed account of the horticultural techniques that can impact the quality of the fruit and its nutritional properties, including water availability, light intensity, temperature, and growing media. The next section provides information on the components of tomato that are likely to contribute to its health effects. The review then details some of the health benefits associated with tomato consumption, including anticancer properties, cardiovascular and neurodegenerative diseases and skin health. This review also discusses the impact tomatoes can have on the gut microbiome and associated health benefits, including reducing the risk of inflammatory bowel diseases. Other health benefits of eating tomatoes are also discussed in relation to effects on diabetes, the immune response, exercise recovery, and fertility. Finally, this review also addresses the negative effects that can occur as a result of overconsumption of tomato products and lycopene supplements.
... Similarly, protein carbonylation (PC) was used as a marker of protein damage, and 8-Hydroxydeoxyguanosine (8-oxodG) as a specific marker of 2 -deoxyguanosine damage after ROS attack to DNA. In this narrative review, n = 14 articles ( [29][30][31][32]37,40,[46][47][48][49][50][51][52][53]) showed the antioxidant effects diets on oxidative stress markers. ...
... Two major potential hypotheses to explain the antioxidant abilities of lycopene are oxidative and nonoxidative mechanisms [69]. In a human trial by Harms-Ringdahl et al., [49], a daily intake of tomato juice, equal to 15 mg lycopene per day for five weeks significantly reduced the serum levels of 8-oxodG after extensive physical exercise. ...
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Exhaustive exercise can induce excessive generation of reactive oxygen species (ROS), which may enhance oxidative stress levels. Although physiological levels are crucial for optimal cell signaling and exercise adaptations, higher concentrations have been demonstrated to damage macromolecules and thus facilitate detrimental effects. Besides single dosages of antioxidants, whole diets rich in antioxidants are gaining more attention due to their practicality and multicomponent ingredients. The purpose of this narrative review is to summarize the current state of research on this topic and present recent advances regarding the antioxidant effects of whole dietary strategies on exercise-induced oxidative stress in humans. The following electronic databases were searched from inception to February 2021: PubMed, Scope and Web of Science. Twenty-eight studies were included in this narrative review and demonstrated the scavenging effects of exercise-induced ROS generation, oxidative stress markers, inflammatory markers and antioxidant capacity, with only one study not confirming such positive effects. Although the literature is still scarce about the effects of whole dietary strategies on exercise-induced oxidative stress, the majority of the studies demonstrated favorable effects. Nevertheless, the protocols are still very heterogeneous and further systematically designed studies are needed to strengthen the evidence.
... However, it is all a pit higher than data obtained herein and that could be related to the difference of the original used tomato or to the variation of the laboratory hands and/or methods used. Also, the antioxidant activity is nearly the same as it is primarily driven by its lycopene content as described before by Harms-Ringdahl et al. (2012). Table 2 shows the effect of TJ on serum blood glucose within the diabetic rat used models. ...
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This study aimed firstly to evaluate the antioxidants levels (Lycopene & Beta-carotene) within fresh tomato juice (FTJ) and its health effects on atherogenic indices in association to lipid profiles and kidney functions between diabetic animal models. Rats (thirty-two; 180 ± 5 g) were randomly divided to groups; control negative (G1; non-diabetic), control positive (G2; fed standard basil diet), and three diabetic groups induced by single dose of streptozotocin (STZ; 65 mg/kg body weight). Groups of diabetic G3 & G4 (given FTJ by gavages at 2 and 4 mL/day respectively). Glucose, lipid profile (Cholesterol, Triglyceride, LDL.c, HDL.c and VLDL.c), kidney functions with atherogenic indices; the activity of glutathione peroxidase (GSH.Px), glutathione reduced (GSH.Rd) and superoxide dismutase (SOD) were evaluated. Results expressed data indicated that fresh tomato juice antioxidant activities presented at 72.83 ± 2.62 while Lycopene and β-carotene levels were 10.37 ± 1.36 and 3.91 ± 0.22 mg/100 mL respectively. Also, FTJ administration at 4 mL/day was the best effective dose; glucose, cholesterol, triglyceride and LDL.c. However, an elevation in the HDL.c, GSH.Px, GSH.Rd, and SOD were seen compared to G2. In conclusion, fresh tomato juice had hypoglycemic and positive atherogenic indices/effects that enhanced the model lipid profile to nearly the normal levels between diabetic rats especially at 4 mL/day.
... This biomarker is drastically increased by physical exercise, 83 and significantly reduced by the intake of tomato juice. 84 Inflammation and cancer -Based on register epidemiological data suffering from extensive bias and confounding, exaggerated estimates of inflammation as the cause of human neoplasia have been widely disseminated. On the other hand, for certain inflammatory processes a causal association between OS and certain cancers has been established beyond doubt, as exemplified by colorectal cancer, Crohn's disease, hereditary hemochromatosis, hepatitis, stomach cancer and pancreatitis. ...
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Background To describe for the first time a patient with ankylosing spondylitis (AS) successfully treated with cycling, and marked improvement of his physical performance after nutraceuticals. Case report A 63-year-old male with a diagnosis of AS. He received several kinds of drugs. He practices physical activity since he was a teenager, and cycling 10 years ago reaching 30km/week. He had excellent disease control with cycling, and all medications were stopped. His physical examination demonstrates limitations of the lumbar and cervical spine movements. X-ray confirmed AS. He was treated with a nutraceutical supplementation and probiotics. He felt a progressive improvement in his physical performance and marked improvement of his mild residual AS clinical symptoms. After 1 year of follow up, he was doing 200km/week by cycling. Conclusion This study illustrates a patient with AS under control, who could get a higher performance cycling after nutraceuticals supplementation.
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The health benefits of tomato, a vegetable consumed daily in human diets, have received great attention in the scientific community, and a great deal of experiments have tested their utility against several diseases. Herein, we present a scientometric analysis of recent works aimed to estimate the biological effects of tomato, focusing on bibliographic metadata, type of testers, target systems, and methods of analysis. A remarkably variable array of strategies was reported, including testers obtained by standard and special tomatoes, and the use of in vitro and in vivo targets, both healthy and diseased. In vitro, 21 normal and 36 cancer human cell lines derived from 13 different organs were used. The highest cytotoxic effects were reported on cancer blood cells. In vivo, more experiments were carried out with murine than with human systems, addressing healthy individuals, as well as stressed and diseased patients. Multivariate analysis showed that publications in journals indexed in the agriculture category were associated with the use of fresh tomatoes; conversely, medicine and pharmacology journals were associated with the use of purified and formulate testers. Studies conducted in the United States of America preferentially adopted in vivo systems and formulates, combined with blood and tissue analysis. Researchers in Italy, China, India, and Great Britain mostly carried out in vitro research using fresh tomatoes. Gene expression and proteomic analyses were associated with China and India. The emerging scenario evidences the somewhat dichotomic approaches of plant geneticists and agronomists and that of cell biologists and medicine researchers. A higher integration between these two scientific communities would be desirable to foster the assessment of the benefits of tomatoes to human health.
Background Phytoene (PT) and phytofluene (PTF) are rarities within carotenoids as they are colorless. Despite they have been mostly ignored in the past, there is strong evidence that they are major dietary carotenoids readily bioavailable in humans that could be involved in health-promoting biological actions. It is not surprising that they are the trendiest among the major dietary carotenoids. Scope and approach In this review, we summarize recent insight and pinpoint sustainable approaches that can be used to innovate in the production of colorless carotenoid-rich products, in alignment with the new challenges posed by the European Union Green Deal and other international frameworks advocating for sustainability. Key findings and conclusions The health-promoting properties of tomato, commonly associated with lycopene, could actually be due to some extent to PT and PTF. It has recently been shown that certain agronomic practices and industrial processes that favor sustainable food production can be harnessed to produce products with enhanced contents or potential bioavailability. Although colorless carotenoids are attracting increased attention they have been scarcely tapped for the development of innovative products.
Antioxidant strategies using dietary approaches are gaining increasing attention in physiological and in functional research. Although several recent studies have shown the positive effects of some antioxidant-rich foods on oxidative stress compared to control diets, evidence is still scarce, particularly from studies applying direct assays to evaluate the generation of reactive oxygen species (ROS). Therefore, the main purpose of the experimental part of this thesis was to investigate the antioxidant effects of dietary strategies on immediate ROS production in vivo during rest and following exercise. Study 1: The first study of this thesis investigated whether changes in the diet that lead to an increased intake of antioxidant micronutrients could affect ROS generation by using electron paramagnetic resonance (EPR) spectroscopy. The individuals enrolled in the study demonstrated nutritional behavior below current national recommendations and were instructed to follow a mixed healthy diet for two weeks. The results indicated that dietary changes led to a significantly increased intake of vitamin C, vitamin E, and β-carotene which was accompanied by a significant decrease in ROS generation. This finding showed that a mixed healthy diet increased dietary intake of antioxidant vitamins and reduced ROS generation. Study 2: The second study investigated the acute effects of oatmeal consumption on high-intensity interval training (HIIT)-induced ROS generation by using EPR detection method. Thirty-four young female participants were randomly allocated to one of two groups: “oatmeal prior to HIIT” or “HIIT alone”. The results showed that ROS generation in the oatmeal group was significantly lower than in the control group immediately after HIIT. A significant interaction between time and meal was detected from the pre-meal to 15 minutes post- HIIT for ROS generation. These findings revealed that the consumption of oatmeal rich in antioxidant secondary plant products before HIIT may mitigate exercise-induced ROS generation. Study 3: In order to further summarize the current state of research concerning the effects of antioxidant-rich diets on exercise-induced oxidative stress, a narrative review of 28 studies was conducted. In general, these studies showed that most dietary strategies attenuated exercise-induced oxidative stress; only one study did not find positive effects. The majority of the included studies demonstrated positive effects of phenol-rich foods on exercise-induced oxidative stress in short-term as well as longer-term experimental designs. Nevertheless, the protocols used in these studies were highly heterogeneous and further systematically designed studies are needed. In summary, the findings from this thesis provide evidence that a diet rich in antioxidant nutrients is an effective strategy for combating oxidative stress both during rest and following exercise. Further studies examining a greater number of dietary regimens and with a special focus on potential mechanisms are warranted to further strengthen the evidence on this topic.
In recent years, there have been studies in the literature reporting the ergogenic effect of some different foods on sports performance. Given the reasonable number of studies in which some food has shown improvement in some physiological variables related to physical performance, a review is pertinent in order to produce a compilation of these studies, providing new elements for athletes and coaches which aim to optimize their performance. Thus, the objective of this work was to present a systematic review of the findings regarding the potential ergogenic effect of food for athletes. Researchers performed a double-blind research in Medline/PubMed considering articles published until January 2019 which resulted in 71 articles. Increased time until exhaustion, improved aerobic capacity and strength recovery were the most commonly reported physical effects. In general, food showed equal or superior ergogenic activity over supplements. Although the number of foods investigated is reasonable, there is still no body of evidence for each studied food, except beets. The current data support the possibility of certain foods being able to enhance athletic performance, as well as serving as an energy source. However, a larger volume of studies is needed to form a body of evidence on each of these foods.
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Physiological levels of reactive oxygen species (ROS) are important for intracellular and extracellular redox regulation in signaling and defense processes. Strenuous exercise can also contribute to this imbalance, and the muscle fatigue, evidenced by impaired strength or power generation, can be caused by various reasons, including oxidative stress. Antioxidants can prevent the formation of ROS by intercepting free radicals. Twenty judo athletes were included in this randomized, double-blind clinical trial into grape juice and placebo groups, and they consumed grape juice or placebo daily for 14 days in a crossover model. The outcomes were analyzed before and after combat simulations. The upper limb strength was higher in the grape juice group than in the placebo (p [group] = 0.003). The lipid damage levels were 10% higher in the placebo group (p [interaction] = 0.048). During the pre-exercise, the placebo group showed 19% more DNA damage than the grape juice group. The superoxide dismutase activity was 80% lower in the grape juice group (p [interaction] < 0.001). The consumption of grape juice can improve parameters of oxidative stress by reducing the lipid and DNA damage.
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Increasing desires from both consumers and producers to understand better which nutritive components are present in our food and how these are influenced by industrial processing strategies is resulting in extra research involving the use of state-of-the-art technologies to generate novel biochemical information. In this review, attention has been focused on tomato as this is a product eaten right across the world both as fresh produce and after having been processed in a wide variety of ways. There is a particular interest in tomato as it is a major component in the so-called "Mediterranean diet" which has recently been associated with a healthier lifestyle. Tomatoes are rich sources of a variety of nutritional compounds and especially some key antioxidant components such as the carotenoid lycopene, vitamin C, and a range of polyphenols. The potentially protective properties of these antioxidants are of great interest and the consumer has already become aware of their potential importance. Surveying the literature has revealed that much research has been done on the biochemical composition of tomato and its products. However, it remains difficult to make clear conclusions on optimizing the processing strategy. Many, apparently conflicting, findings have been reported and consequently, in this review, we have drawn attention to these and have attempted to clarify their cause. Finally, a range of recommendations has been made as to how future research might be performed in order to generate more concrete conclusions enabling recommendations towards more optimized processing strategies.
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Oxidative stress occurs when the generation of reactive oxygen species (ROS) exceeds the cellular antioxidant capacity. The excess ROS react with and modify cellular components. Nucleic acid modifications are of principal interest because they may cause mutations. 8-Oxo-7,8-dihydro-2 -deoxyguanosine (8-oxo-dG) is a mutagenic lesion that can be formed by ROS in DNA as well as in the nucleotide pool. 8-Oxo-dG is removed from the DNA by base excision repair and from the nucleotide pool by the nucleotide sanitization enzyme hMTH1. hMTH1 hydrolyzes 8-oxo-dGTP to 8-oxo-dGMP, which is released to the extracellular environment and can serve as a marker of oxidative stress. The aim of this work was to establish the dose-response relationship for radiation-induced extracellular 8-oxo-dG and hMTH1 in the mGy range of gamma rays in three cellular model systems: human whole blood, human fibroblasts and stimulated lymphocytes. Extracellular 8-oxo-dG was analyzed with the use of an ELISA and hMTH1 by Western blotting. Our results demonstrate that low-dose ionizing radiation induces a stress response that leads to the formation of extracellular 8-oxo-dG and induction of hMTH1 in all three cellular model systems tested. This suggests that the nucleotide pool is an important target for radiation-induced stress response.
Lycopene is a potent antioxidant found in watermelon, tomato, and red grapefruit and may exert positive effects on human health. Spectrophotometric and HPLC techniques are commonly employed for analysis of lycopene content in food sources. A rapid and inexpensive spectrophotometric assay for lycopene is presented. This method requires 80% less organic solvents for release and extraction of lycopene from watermelon than do the existing procedures. Comparative analyses for 105 watermelons from 11 cultivars yielded results equivalent to those provided by larger-volume spectrophotometric assay procedures. Limited numbers of assays suggest that this reduced volume method may be applicable for tomatoes and tomato products.
There is increasing evidence to suggest that physical activity has a protective effect on brain functioning in older people. To date, no randomized controlled trial (RCT) has shown that regular physical activity prevents dementia, but recent RCTs suggests an improvement of cognitive functioning in persons involved in aerobic programs, and evidence is accumulating from basic research. Future prevention of Alzheimer disease may depend on lifestyle habits such as physical activity.
Oxidative damage to DNA is regarded as an important step in carcinogenesis. These lesions may arise as a consequence of exposure to xenobiotics, but are also generated as a consequence of endogenous generation of oxidizing compounds. Measurements of oxidative damage to guanines, such as 8-oxo-7, 8-dihydroguanine (8-oxodG) are increasingly being regarded as reliable biomarkers of oxidative stress and they may have a predictive value of cancer risk, although this needs to be established independently in several cohort studies. A survey of intervention studies of the ingestion of antioxidant-containing foods or tablets of antioxidants indicate that about one-third of the studies reported a protective effect in terms of lower levels of oxidative damage to DNA in white blood cells or decreased urinary excretion of 8-oxodG. Although firm conclusions cannot be reached, there appears to be links between ingestion of antioxidants, oxidative damage to DNA, and risk of cancer. This review was written as a part of the research integration in the Workpackage “Mechanisms of modulation of cancer by dietary factors” in the NoE Environmental Cancer risk, Nutrition and Individual Susceptibility (ECNIS, no. 513943;”
Also physical exercise in general is accepted to be protective, acute and strenuous exercise has been shown to induce oxidative stress. Enhanced formation of free radicals leads to oxidation of macromolecules and to DNA damage. On the other hand ultra-endurance events which require strenuous exercise are very popular and the number of participants is continuously increasing worldwide. Since only few data exists on Ironman triathletes, who are prototypes of ultra-endurance athletes, this study was aimed at assessing the risk of oxidative stress and DNA damage after finishing a triathlon and to predict a possible health risk. Blood samples of 42 male athletes were taken 2 days before, within 20 min after the race, 1, 5 and 19 days post-race. Oxidative stress marker increased only moderately after the race and returned to baseline after 5 days. Marker of DNA damage measured by the SCGE assay with and without restriction enzymes as well as by the sister chromatid exchange assay did either show no change or deceased within the first day after the race. Due to intake during the race and the release by the cells plasma concentrations of vitamin C and α-tocopherol increased after the event and returned to baseline 1 day after. This study indicates that despite a temporary increase in some oxidative stress markers, there is no persistent oxidative stress and no DNA damage in response to an Ironman triathlon in trained athletes, mainly due to an appropriate antioxidant intake and general protective alterations in the antioxidant defence system.
Endogenous oxidative processes are shown to generate hydrogen peroxide and .OH radicals, which react in vivo to form a variety of products. Thymidine glycol (Tg) and 8-hydroxydeoxyguanosine (8-dRG-OH) are such products. They result from the excision repair of DNA and are excreted in urine. Both products can be used as biomarkers in the dosimetry of oxidative damage to DNA. Since oxidative processes and accumulation of their effects contribute to carcinogenesis, the proposed rate-of-damage hypothesis provides a rationale for using these biomarkers in early diagnostics and in the assessment of carcinogenic and anticarcinogenic properties of diets, foods, and food components, as well as certain exogenous toxicants and agents. Approaches for measurement of urinary biomarkers of DNA damage are reviewed.
Oxidative DNA damage may be implicated in ageing, carcinogenesis and other degenerative diseases. Oxidative DNA damage can be assessed in humans in vivo from the urinary excretion of the DNA-repair product 8-hydroxydeoxyguanosine (8OHdG). We investigated factors influencing the excretion of 8OHdG in 24 h urine from 83 randomly selected healthy subjects (52 women) aged 40-64 years. For 2 weeks prior to urine collection the subjects kept a weighed diet record. 8OHdG was quantified by an automatic three-dimensional HPLC analysis with electrochemical detection. The 8OHdG excretion was 252 +/- 103 (mean +/- SD) pmol kg body weight/24 h with a range from 78 to 527. Multiple regression analysis identified three factors, smoking, body mass index (BMI) and gender, as significant predictors of the 8OHdG excretion. In 30 smokers the 8OHdG excretion was 320 +/- 99 pmol/kg/24 h opposed to 213 +/- 84 pmol/kg/24 h in 53 non-smokers. According to multiple regression analysis smokers excreted 50% (31-69%; 95% confidence interval) more 8OHdG than non-smokers. In 52 women the 8OHdG excretion was 240 +/- 106 pmol/kg/24 h opposed to 271 +/- 96 pmol/kg/24 h in 31 men. According to the multiple regression analysis men excreted 29% (10-48%) more 8OHdG than women. According to multiple regression analysis the 8OHdG excretion decreased with 4% (2-6%) per increment in BMI measured in kg/m2. The dietary distribution of energy demonstrated no important predictive value with respect to 8OHdG excretion. The intake of the antioxidant vitamins C and E and of vitamin A equivalents, including beta-carotene, was not associated with 8OHdG excretion. The results suggest that smoking increases oxidative DNA damage by approximately 50%. This effect implies potential serious health effects adding to the other well-known health hazards of smoking. The higher 8OHdG excretion in men and lean subjects may be related to a higher rate of metabolism with increased availability of reactive oxygen species. The apparent 7-fold individual variation in oxidative DNA damage carries implications regarding the rate of ageing and the risk of cancer and other degenerative diseases. The excretion of 8OHdG into urine offers a valuable tool for testing such hypotheses in humans.
Exercise induces free radical formation in muscle and liver, and oxidative damage, such as lipid peroxidation. The amount of damage depends on exercise intensity, training state and the tissue examined and can be reduced through dietary supplementation of antioxidants such as vitamin E and possibly coenzyme Q10. Supplementation with antioxidants does not increase maximal aerobic capacity or maximal exercise capacity; effects on endurance capacity are unclear. Deficiency of vitamin E or vitamin C greatly reduces endurance capacity, whereas selenium deficiency has no effect on endurance capacity. In studies by the authors, urinary output of the oxidatively damaged RNA base 8-hydroxyguanosine was not affected by several submaximal exercise bouts nor by supplementation with vitamins E and C and beta-carotene in moderately trained humans. In rats, endurance training caused an increase in oxidative damage, as measured by the protein carbonyl concentration of muscle, but not liver. Muscle protein carbonyl concentration returned to normal on detraining. These results indicate that the search for oxidative damage due to exercise and the effects of antioxidant manipulation on such damage should ideally involve examination of several indices of oxidative damage in various tissues after exercise and training.