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The effects of ketogenic diet on oxidative stress and antioxidative capacity markers of Taekwondo athletes

December 2014
Journal of Exercise Rehabilitation 10(6):362-6

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The purpose of this study was to investigate the effects of the ketogenic diet through 3 weeks on oxidative stress and antioxidative capacity markers in Taekwondo athletes. The participants selected for this research were 18 high school taekwondo contestants aged 15-18 who had at least 5 yr of career as contestant. The subjects were randomly assigned to the ketogenic diet (KD) group and the Non ketogenic diet (NDK) group. Body composition and oxidative stress and antioxidative capacity markers (LDH, MDA, ROS, HDL, and SOD) were analysed before and after 3 weeks of ketogenic diet. No significant difference was found between the groups in body composition, ROS and SOD level. The KD group showed an elevated HDL level and NKD group showed an elevated LDH and MDA level after ketogenic diet by 3 weeks. This result suggests that weight loss by 3 weeks of calorie restriction and exercise can cause oxidative stress, and that ketogenic diet can be effective for preventing it. It could also be inferred that ketogenic diet can be effective for increasing blood antioxidative capacity.

. Physical characteristics of the subjects

…

. Changes in body composition

…

. Oxidative stress and antioxidative capacity markers

…

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362

*Corresponding author: Hee-Tae Roh

Department of Physical Education, Yonsei University, 50 Yonsei-ro,

Seodaemun-gu, Seoul 120-749, Korea

Tel: +82-2-2123-3199, Fax: +82-2-2123-3199, E-mail: htroh@yonsei.ac.kr

Received: December 2, 2014 / Accepted: December 17, 2014

The effects of ketogenic diet on oxidative stress and

antioxidative capacity markers of Taekwondo athletes

Hyun-seung Rhyu

, Su-Youn Cho

, Hee-Tae Roh

Department of Sports Health Medicine, College of Health Science, Jungwon University, Goesan-gun, Chungcheongbuk-do, Korea

Department of Human Movement Science, Seoul Women’s University, Seoul, Korea

Department of Physical Education, Yonsei University, Seoul, Korea

The purpose of this study was to investigate the effects of the ketogenic

diet through 3 weeks on oxidative stress and antioxidative capacity

markers in Taekwondo athletes. The participants selected for this re-

search were 18 high school taekwondo contestants aged 15-18 who

had at least 5 yr of career as contestant. The subjects were randomly

assigned to the ketogenic diet (KD) group and the Non ketogenic diet

(NDK) group. Body composition and oxidative stress and antioxidative

capacity markers (LDH, MDA, ROS, HDL, and SOD) were analysed be-

fore and after 3 weeks of ketogenic diet. No significant difference was

found between the groups in body composition, ROS and SOD level.

The KD group showed an elevated HDL level and NKD group showed

an elevated LDH and MDA level after ketogenic diet by 3 weeks. This

result suggests that weight loss by 3 weeks of calorie restriction and

exercise can cause oxidative stress, and that ketogenic diet can be ef-

fective for preventing it. It could also be inferred that ketogenic diet can

be effective for increasing blood antioxidative capacity.

Keywords: Taekwondo, Ketogenic diet, Oxidative stress, Antioxidative

capacity

INTRODUCTION

Contestants participating in a weight class contest must meet a

certain weight limit. Since a contestant with a heavier weight usually

has relatively stronger muscle power than one with a lighter weight,

most contestants with heavier weights attempt to lose weight in ab-

normal ways so as to take advantage of their stronger muscle power

by participating in contests of lower weight classes than their nor-

mal weight classes. Most of the weight loss methods used by weight

class contestants involve artificially induced short-term dehydra-

tion, restricted diet, and severe exercise inducing body fluid loss. It

has been reported that such methods might cause increased reac-

tive oxygen species (ROS) production (Anuradha and Balakrish-

nan, 1998).

ROS, produced by physiological metabolism or external stimuli,

are receiving growing recognition as a major factor that induces ox-

idative stress and thereby causes not only cell and tissue damage

but also accelerated aging and various diseases (including cardio-

vascular diseases, cancers, Alzheimer’s disease and Parkinson’s dis-

ease) (Fruehauf and Meyskens, 2007; Weinberg and Chandel,

2009). In addition, it was reported that accelerated lipid peroxida-

tion caused by ROS had a positive correlation with skeletal muscle

damage (Daekeun et al., 2012).

For this reason, an effective weight loss method has continuously

been demanded that does not deteriorate the performance and

health of the weight class contestants who definitely need weight

loss (Paoli et al., 2012). Meanwhile, Nazarewicz et al. (2007) re-

ported that 14 days of ketogenic diet with dietary restriction in-

volving healthy adult women resulted in weight loss and signifi-

cant improvement in total antioxidative status, without causing

blood oxidative stress. Ketogenic diet is a low carbohydrate and

high fat diet that causes the concentration of ketone bodies, which

are by-products of fat burning, to become higher than that of glu-

cose in the blood. When such a physiological state, called ketosis,

http://dx.doi.org/10.12965/jer.140178

Original Article

Journal of Exercise Rehabilitation 2014;10(6):362-366

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Rhyu H, et al. • Effect of ketogenic diet on oxidative stress

is reached, fat begins to be burned fast, fat accumulation stops, and

fat becomes the main source of energy metabolism (Pethick and

Lindsay, 1982). In the research of Nazarewicz et al. (2007), howev-

er, ketogenic diet was conducted without a control group, and

therefore it is not clear whether the antioxidant effect was due to

ketogenic diet or due to weight loss caused by dietary restriction.

There have been some other researches reporting the oxidative

stress and antioxidant effect by ketogenic diet, but most of their

research subjects were patients with diseases; moreover, their re-

sults disagree with each other (Gasior et al., 2006; Jain et al., 1999;

Leornardi et al., 2010; Nazarewicz et al., 2007).

Therefore, the present research involved male high school tae-

kwondo contestants to verify the efficacy of ketogenic diet for

weight loss by examining the effect of 3 weeks of diet on oxidative

stress and antioxidative capacity.

MATERIALS AND METHODS

Participants

The participants selected for this research were 18 high school

taekwondo contestants aged 15-18 who had at least 5 yr of career

as contestant and who neither had particular medical diseases (such

as muscular skeletal diseases, genetic diseases and heart diseases)

nor was taking dietary supplements (such as vitamins).

The participants were randomly assigned to 2 groups: 9 of them

to the ketogenic diet (KD) group, and the remaining 9 to the non

ketogenic diet (NDK) group. Their physical characteristics are

presented in Table 1.

Experimental procedures

Evaluation of body mass and body composition

Before and after the 3 weeks of experimental diet period, the sub-

jects fasted 12 h. Then, wearing a simple cloth in the morning, they

were subjected to the measurement of body composition. In order

to evaluate changes in body composition caused by the 3 weeks of

KD and NKD, respectively, measurements were taken of height,

weight and BMI, as well as of %body fat and lean body mass us-

ing the electric resistance method.

Method and procedure for diet

Before the experimental diet period, every research subject pre-

pared a document stating calorie intake for 3 days, and their daily

mean calorie intake was calculated. Then each of the KD and

NKD groups was provided with a different menu containing 75%

of the calculated daily mean calories.

Based on the menu used by Paoli et al. (2012), the menu for the

KD group consisted of high fat foods (such as beef, pork, fish,

bean, egg and cheese) whose lipid, protein and carbohydrate con-

tents were 55.0%, 40.7%, and 4.3%, respectively; while alcohol,

bread, rice, noodles, coffee and tea were restricted. Whereas the

NKD group was provided with a menu whose lipid, protein and

carbohydrate contents were 30%, 30%, and 40%, respectively.

Exercise program

Six days a week for 3 weeks during the weight loss period, both

groups participated in a training program that emphasized physi-

cal strength improvement. The daily plan of the program consisted

of 1 h of low intensity dawn exercise; 2 h of morning exercise, most-

ly for physical strength improvement; and 2 h of afternoon exer-

cise, mostly for taekwondo skills training.

Blood collection and analysis

Blood was collected from the antecubital vein using 22 gage

needles, in the morning of the day before the beginning of the

study, and in the morning after the 3 weeks of the study. The col-

lected blood was subjected to analysis of lactatedehydrogenase

(LDH), malondialdehyde (MDA), ROS, superoxide dismutase

(SOD) , high density lipoprotein (HDL). Serum LDH and HDL

concentrations were detected by biochemical analyzer (Kodak,

USA). Serum ROS levels were determined using an OxiSelect

Vitro ROS/RNS Assay Kit (#STA-347, CELL BIOLABS, USA).

The MDA concentrations in the sera were determined by the Col-

orimetric Assay, using commercially available BIOXYTECH

LPO-586 kit (#21012, Oxis, USA). The SOD concentrations in

the sera were determined by the Colorimetric Assay, using com-

mercially available Superoxide Dismutase Assay Kit(#CM706002,

IBL-Internationall, Germany). All reagents, dilutions, and calcula-

tions were applied according to the manufacturer’s instructions.

The absorbance was measured at 450 nm with a microplate reader

(GENios, TECAN, Austria).

Statistical analyses

Data are presented as means

standard deviation (SD). The sig-

nificance of differences among mean values between pre and post-

Table 1. Physical characteristics of the subjects

Group (n = 20) Age (yr) Height (cm) Weight (kg)

KD (n = 10) 16.22 ± 0.79 174.41 ± 5.30 64.37 ± 5.21

NKD (n = 10) 16.67 ± 0.82 172.48 ± 6.19 62.51 ± 6.684

Values are means ± SD. KD, ketogenic diet; NKD, non-ketogenic diet.

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Rhyu H, et al. • Effect of ketogenic diet on oxidative stress

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diet, as well as between KD and NKD groups, were determined by

two-way analysis of variance (ANOVA) using SPSS 18.0 for Win-

dows. Statistical significance was set at

0.05.

RESULTS

Body composition

Changes in body mass and body composition after diet, com-

pared to before diet, by the diet groups are presented in Table 2.

Compared to before the diet period, there was significant de-

crease in weight after the period, as well as in %body fat, fat free

mass and BMI (P

0.05). However, no difference was found be-

tween the KD and NKD groups, and there was also no effect of

interaction between the independent variables.

Oxidative stress and antioxidative capacity markers

Changes in oxidative stress and antioxidative capacity markers

after diet during 3 weeks, compared to before diet, by the diet groups

are presented in Table 3.

In the cases of ROS and SOD, no significant difference was found

Table 2. Changes in body composition

Variables

KD (n = 10) NKD (n = 10)

F-value

Pre Post Pre Post

Weight (kg) 64.37 ± 5.52 60.99 ± 6.65 62.51 ± 7.08 60.11 ± 7.54 G 0.188

T 50.971*

G×T 1.460

%Body fat (%) 13.04 ± 3.88 11.90 ± 3.19 10.93 ± 1.36 10.21 ± 2.03 G 2.186

T 10.420*

G×T 0.533

Lean body mass (kg) 55.01 ± 3.99 52.72 ± 4.88 54.97 ± 6.90 52.78 ± 8.26 G 0.000

T 28.782*

G×T 0.014

BMI (kg/m

) 21.13 ± 0.98 19.97 ± 1.15 20.94 ± 1.30 20.13 ± 1.44 G 0.000

T 53.656*

G×T 1.734

Values are means ± SD. KD, ketogenic diet; NKD, non-ketogenic diet. *P < 0.05.

Table 3. Oxidative stress and antioxidative capacity markers

KD (n = 10) NKD (n = 10)

F-value

Pre Post Pre Post

LDH (U/L) 404.89 ± 55.94 399.78 ± 76.39 395.56 ± 32.12 422.00 ± 33.47 G 0.074

T 2.125

G×T 4.650*

MDA (pmol/mg) 0.134 ± 0.080 0.131 ± 0.064 0.131 ± 0.07 0.184 ± 0.048 G 0.745

T 4.171

G×T 5.316*

ROS (pg/mL) 87.16 ± 30.31 88.84 ± 21.57 77.73 ± 15.89 82.63 ± 30.23 G 0.638

T 0.241

G×T 0.057

HDL (mg/dL) 59.21 ± 8.41 73.32 ± 13.15 61.14 ± 6.67 63.81 ± 7.86 G 0.863

T 25.029*

G×T 11.646*

SOD (%SOD activity) 50.34 ± 5.32 46.70 ± 3.52 47.98 ± 2.55 47.25 ± 3.1 G 0.518

T 3.75

G×T 1.661

Values are means ± SD. KD, ketogenic diet; NKD, non-ketogenic diet. *P < 0.05.

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Rhyu H, et al. • Effect of ketogenic diet on oxidative stress

between the independent variables. In contrast, in the case of LDH,

MDA and HDL interaction effect was found when comparison was

made between before and after diet and between diet groups

0.05). According to result of the main effect analysis, the KD

group showed an elevated HDL level and NKD group showed an

elevated both LDH and MDA level after diet compared to before

diet (P

0.05).

DISCUSSION

During the last several yr, there have been many research reports

that proved the effects of ketogenic diet on short-term weight loss,

as well as on metabolic profile with regard to insulin sensitivity,

glycemic control and serum lipid values (Nazarewicz et al., 2007;

Stafford et al., 2010; Veech, 2004). In addition, Paoli et al. (2012)

reported that 30 days of ketogenic diet could decrease the weight

and body fat mass of elite artistic gymnasts without affecting their

performance. Such research results show that ketogenic diet can be

very effective for weight class contestants who need rapid short-

term weight loss without negative effect on performance. Howev-

er, in spite of many reports on the effect of ketogenic diet, there

have been rare researches that involved athletic contestants to in-

vestigate the effect of short-term ketogenic diet on body mass and

body composition.

Therefore the present research involved taekwondo contestants

to examine the weight loss effect of 3 weeks of ketogenic diet vs

common diet, with calorie restriction. The result showed that 3

weeks of Ketogenic diet and Non ketogenic diet both caused de-

creases of weight, body fat mass and BMI, and that there was no

difference between the 2 groups in the extent of such decreases. In

addition, although Paoli et al. (2012) reported that ketogenic diet

could increase muscle mass, the result of the present research

showed decrease of lean body mass in both groups. Such a differ-

ence is considered due to the effect of the 25% calorie restriction

and extensive aerobic exercise program that were used for both

groups in this research, because preceding researches on ketogenic

diet did not involve calorie restriction.

Ketogenic diet leads to the production of ketone bodies, such as

-hydroxybutyrate and acetoacetate, which can be used as an alter-

native energy source. There is a recent report that ketone bodies

potentially decreased ROS production (Bough and Rho, 2007;

Gredilla and Barja, 2005). In the present research, however, both of

the 2 groups showed no change in ROS after the 3 weeks of diet.

Instead, increases in LDH and MDA were shown by the NKD

group after the 3 weeks of diet, but not by the KD group. Oxida-

tive stress caused by exercise can results in damage to skeletal mus-

cle cells, which in turn leads to increase of LDH (Brancaccio et al.,

2010). MDA is produced as the result of the degradation of poly-

unsaturated fatty acid peroxidation products, and it has been used

as a traditional oxidative stress index (Rachmilewitz et al., 1976).

In addition, increase of HDL was also shown after the 3 weeks of

KD diet in the present research. HDL has been known to be a po-

tential antioxidant suppressing the accumulation of oxidized lipids

(Vohl et al., 1999). In a research involving healthy women, Naza-

rewicz et al. (2007) showed that 14 days of ketogenic diet resulted

in improved total antioxidative status as well as increased uric acid

and HDL levels. They interpreted this result as demonstrating the

effect of ketogenic diet on antioxidative capacity. Accordingly, the

result of the present research indicates that weight loss by 3 weeks

of calorie restriction and exercise can cause oxidative stress, and

that ketogenic diet can be effective for preventing it. It could also

be inferred that ketogenic diet can be effective for increasing blood

antioxidative capacity.

Researches concerning the effects of ketogenic diet on oxidative

stress and antioxidative capacity have reported opposite results ac-

cording to the kinds of the diseases of research subjects, while re-

search involving healthy individuals has been very insufficient. Es-

pecially, there has been no research report involving weight class

contestants, and additional research would have to be carried out in

this regard.

CONFLICT OF INTEREST

No potential conflict of interest relevant to this article was re-

ported.

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Sep 2022

Background: Sub-Saharan Africa is not insusceptible to the obesity epidemic, regardless of the continued problem of undernutrition. Increases in the rates of overweight and obesity are being identified in Sub-Saharan Africa, especially among women and people dwelling in urban populations. This study, therefore, is aimed at evaluating the effects of ketogenic diet on markers of oxidative stress (reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA)) in obese female subjects on eight weeks ketogenic diet.Methods: A total of forty (40) participants, 10 overweight (25.0–29.9 kg/m2) and 30 obese (≥30 kg/m2) female subjects, were recruited and investigated via informed consent and approval obtained. The sera of the participants were collected by standard, sterile with a minimal invasive procedure for reduced glutathione, catalase, superoxide dismutase, malondialdehyde at weeks 0, 4, and 8 of ingestion of low carbohydrate ketogenic diet (LCKD).Results: There was a statistically significant increase in mean superoxide dismutase levels of participants at the 4th and 8th week after the introduction of low carbohydrate ketogenic diet (LCKD). There were also statistically insignificant changes in catalase and malondialdehyde levels in the participants between the baseline (week 0) and 4th and 8th weeks. Mean reduced glutathione was statistically significant at week 4 when compared with the baseline.Conclusions: Ketogenic diet reduces oxidative stress as evidenced by increased reduced glutathione and superoxide dismutase.

Inflammation and oxidative stress in epileptic children: from molecular mechanisms to clinical application of ketogenic diet

Article

Feb 2024
REV NEUROSCI

Childhood epilepsy affects up to 1 % of children. It has been shown that 30 % of patients are resistant to drug treatments, making further investigation of other potential treatment strategies necessary. One such approach is the ketogenic diet (KD) showing promising results and potential benefits beyond the use of current antiepileptic drugs. This study aims to investigate the effects of KD on inflammation and oxidative stress, as one of the main suggested mechanisms of neuroprotection, in children with epilepsy. This narrative review was conducted using the Medline and Google Scholar databases, and by searching epilepsy, drug-resistant epilepsy, child, children, ketogenic, ketogenic diet, diet, ketogenic, keto, ketone bodies (BHB), PUFA, gut microbiota, inflammation, inflammation mediators, neurogenic inflammation, neuroinflammation, inflammatory marker, adenosine modulation, mitochondrial function, MTOR pathway, Nrf2 pathway, mitochondrial dysfunction, PPARɣ, oxidative stress, ROS/RNS, and stress oxidative as keywords. Compelling evidence underscores inflammation and oxidative stress as pivotal factors in epilepsy, even in cases with genetic origins. The ketogenic diet effectively addresses these factors by reducing ROS and RNS, enhancing antioxidant defenses, improving mitochondrial function, and regulating inflammatory genes. Additionally, KD curbs pro-inflammatory cytokine and chemokine production by dampening NF-κB activation, inhibiting the NLRP3 inflammasome, increasing brain adenosine levels, mTOR pathway inhibition, upregulating PPARɣ expression, and promoting a healthy gut microbiota while emphasizing the consumption of healthy fats. KD could be considered a promising therapeutic intervention in patients with epilepsy particularly in drug-resistant epilepsy cases, due to its targeted approach addressing oxidative stress and inflammatory mechanisms.

Ketogenic diet as a metabolic therapy for bipolar disorder: Clinical developments

Article

Dec 2022

Background Key underlying metabolic pathologies are thought to play a role in bipolar disorder (BD), including dysfunctions in energy metabolism. This review highlights underlying metabolic mechanisms of BD and potential therapeutic effects of a low carbohydrate ketogenic diet (KD) on mood symptoms. Based on its robust effectiveness in treating epilepsy, the KD has garnered recent interest in its application for mood disorders as it may imitate the pharmacological effects of mood stabilizers, commonly prescribed agents in the treatment of both BD and epilepsy, amongst other effects on stabilizing neural networks in the brain. Methods A literature review was conducted on current metabolic mechanisms of BD and clinical developments in KD. Results Recent findings support the idea that BD may have roots of metabolic dysfunction: cerebral glucose hypometabolism, oxidative stress, as well as mitochondrial and neurotransmitter dysfunction. A KD provides alternative fuel to the brain and is believed to contain beneficial neuroprotective effects, including neural network stabilization and inflammation reduction. Several beneficial metabolic effects on insulin resistance, weight, and lipid composition have been shown. Limitations Limited case studies on KD treatment in BD have been reported to date. Conclusions Preliminary data support further testing of a low carbohydrate KD as a potential therapeutic tool in repairing energy metabolism in bipolar illness. Additionally, it may repair deficits in energy metabolism often seen in BD. Further research and clinical trials are needed to evaluate the efficacy of a KD as a supplemental or co-treatment of bipolar illness and an open-label pilot trial testing the diet in bipolar illness is currently underway at Stanford.

Lipid Membrane Peroxidation in fl-Thalassemia Major

Article

Full-text available

Mar 1976
BLOOD

The composition of membrane lipids was studied in 17 splenectomized and eight unsplenectomized patients with β thalassemia major and compared to normal controls. The results showed a nearly twofold increase in total cell lipids; a reduction in the percentage, but not the absolute amount of phosphatidylethanolamine, and a corresponding increase in phosphatidylcholine in the lipids; a considerable increase in the percentage of the saturated fatty acid, palmitic acid, and a reciprocal decrease in the polyunsaturated fatty acid, arachidonic acid; a twofold increase in the amount of malonyldialdehyde (MDA) generated after peroxide threat to the RBC when calculated either per gram hemoglobin or per cell; no change in the amount of MDA generated when calculated per microgram of membrane phosphorus at risk per cell; and a considerable decrease in serum α tocopherol (vitamin E) levels. Thalassemic erythrocytes contain more lipid per cell which is susceptible to peroxidation. In addition, the distribution of fatty acids in these cells suggests that autooxidation of that lipid may have occurred. Autooxidation may be initiated by free radicals, which are constantly formed in the normal red cell, and may be especially prevalent when unstable hemoglobins are present. The low MCHC or some other intracellular defect of thalassemic cells may allow such potent oxidants to find their way to the cell membrane. Vitamin E, a biologic antioxidant, is decreased in these patients, and clinical supplementation may be indicated to prevent some of the membrane damage in thalassemia.

Ketogenic diet does not affect strength performance in elite artistic gymnasts

Article

Full-text available

Jul 2012
Sports Nutr Rev J

Background: Despite the increasing use of very low carbohydrate ketogenic diets (VLCKD) in weight control and management of the metabolic syndrome there is a paucity of research about effects of VLCKD on sport performance. Ketogenic diets may be useful in sports that include weight class divisions and the aim of our study was to investigate the influence of VLCKD on explosive strength performance. Methods: 8 athletes, elite artistic gymnasts (age 20.9 ± 5.5 yrs) were recruited. We analyzed body composition and various performance aspects (hanging straight leg raise, ground push up, parallel bar dips, pull up, squat jump, countermovement jump, 30 sec continuous jumps) before and after 30 days of a modified ketogenic diet. The diet was based on green vegetables, olive oil, fish and meat plus dishes composed of high quality protein and virtually zero carbohydrates, but which mimicked their taste, with the addition of some herbal extracts. During the VLCKD the athletes performed the normal training program. After three months the same protocol, tests were performed before and after 30 days of the athletes' usual diet (a typically western diet, WD). A one-way Anova for repeated measurements was used. Results: No significant differences were detected between VLCKD and WD in all strength tests. Significant differences were found in body weight and body composition: after VLCKD there was a decrease in body weight (from 69.6 ± 7.3 Kg to 68.0 ± 7.5 Kg) and fat mass (from 5.3 ± 1.3 Kg to 3.4 ± 0.8 Kg p < 0.001) with a non-significant increase in muscle mass. Conclusions: Despite concerns of coaches and doctors about the possible detrimental effects of low carbohydrate diets on athletic performance and the well known importance of carbohydrates there are no data about VLCKD and strength performance. The undeniable and sudden effect of VLCKD on fat loss may be useful for those athletes who compete in sports based on weight class. We have demonstrated that using VLCKD for a relatively short time period (i.e. 30 days) can decrease body weight and body fat without negative effects on strength performance in high level athletes.

The ketogenic diet reverses gene expression patterns and reduces reactive oxygen species levels when used as an adjuvant therapy for glioma

Article

Full-text available

Sep 2010
NUTR METAB

Malignant brain tumors affect people of all ages and are the second leading cause of cancer deaths in children. While current treatments are effective and improve survival, there remains a substantial need for more efficacious therapeutic modalities. The ketogenic diet (KD) - a high-fat, low-carbohydrate treatment for medically refractory epilepsy - has been suggested as an alternative strategy to inhibit tumor growth by altering intrinsic metabolism, especially by inducing glycopenia. Here, we examined the effects of an experimental KD on a mouse model of glioma, and compared patterns of gene expression in tumors vs. normal brain from animals fed either a KD or a standard diet. Animals received intracranial injections of bioluminescent GL261-luc cells and tumor growth was followed in vivo. KD treatment significantly reduced the rate of tumor growth and prolonged survival. Further, the KD reduced reactive oxygen species (ROS) production in tumor cells. Gene expression profiling demonstrated that the KD induces an overall reversion to expression patterns seen in non-tumor specimens. Notably, genes involved in modulating ROS levels and oxidative stress were altered, including those encoding cyclooxygenase 2, glutathione peroxidases 3 and 7, and periredoxin 4. Our data demonstrate that the KD improves survivability in our mouse model of glioma, and suggests that the mechanisms accounting for this protective effect likely involve complex alterations in cellular metabolism beyond simply a reduction in glucose.

Low-Carbohydrate and High-Fat Diets on the Promotion of Hepatic Steatosis in Rats

Article

Full-text available

Nov 2010
EXP CLIN ENDOCR DIAB

The present work looked for to evaluate in rats the impact of different diets (high-lipid and high-lipid+high-protein) on liver, verifying the occurrence of oxidative stress and steatosis. The animals were treated with the respective diets (Group HLS: high-lipid diet with 50% of saturated fat; Group HPLS: high-lipid and high-protein diet with 50% of saturated fat and 40% of protein; Group Control: control diet AIN-93) for 28 days. After this period the animals were sacrificed for hepatic determinations of MDA, reduced GSH, vitamin E, steatosis and glycemia. The results showed higher glycemia in the group HPLS, high concentration of MDA and GSH in the group Control and decreased hepatic vitamin E concentration in the groups that received the high-lipid diets. The hepatic fat was higher in the groups HPLS and HLS in relation to the Group Control, however HPLS presenting high level of fat concentration, showing similar results as the steatosis. the fat increase in the diet promoted increase of the oxidative stress, evidenced by the decrease in the hepatic concentration of vitamin E, showing its antioxidant role against the probable generated free radicals, the ones which possibly exercised a role in the steatosis occurrence.

Biochemical markers of muscular damage

Article

Full-text available

Jun 2010

Muscle tissue may be damaged following intense prolonged training as a consequence of both metabolic and mechanical factors. Serum levels of skeletal muscle enzymes or proteins are markers of the functional status of muscle tissue, and vary widely in both pathological and physiological conditions. Creatine kinase, lactate dehydrogenase, aldolase, myoglobin, troponin, aspartate aminotransferase, and carbonic anhydrase CAIII are the most useful serum markers of muscle injury, but apoptosis in muscle tissues subsequent to strenuous exercise may be also triggered by increased oxidative stress. Therefore, total antioxidant status can be used to evaluate the level of stress in muscle by other markers, such as thiobarbituric acid-reactive substances, malondialdehyde, sulfhydril groups, reduced glutathione, oxidized glutathione, superoxide dismutase, catalase and others. As the various markers provide a composite picture of muscle status, we recommend using more than one to provide a better estimation of muscle stress. Clin Chem Lab Med 2010;48:757–67.

Lipid peroxidation in β-thalassaemia major

Article

Full-text available

Apr 1976

The composition of membrane lipids was studied in 17 splenectomized and eight unsplenectomized patients with beta-thalassemia major and compared to normal controls. The results showed a nearly twofold increase in total cell lipids; a reduction in the percentage, but not the absolute amount of phosphatidylethanolamine, and a corresponding increase in phosphatidylcholine in the lipids; a considerable increase in the percentage of the saturated fatty acid, palmitic acid, and a reciprocal decrease in the polyunsaturated fatty acid, arachidonic acid; a twofold increase in the amount of malonyldialdehyde (MDA) generated after peroxide threat to the RBC when calculated either per gram hemoglobin or per cell; no change in the amount of MDA generated when calculated per microgram of membrane phosphorus at risk per cell; and a considerable decrease in serum alpha-tocopherol (vitamin E) levels. Thalassemic erythrocytes contain more lipid per cell which is susceptible to peroxidation. In addition, the distribution of fatty acids in these cells suggests that autooxidation of that lipid may have occurred. Autooxidation may be initiated by free radicals, which are constantly formed in the normal red cell, and may be especially prevalent when unstable hemoglobins are present. The low MCHC or some other intracellular defect of thalassemic cells may allow such potent oxidants to find their way to the cell membrane. Vitamin E, a biologic antioxidant is decreased in these patients, and clinical supplementation may be indicated to prevent some of the membrane damage in thalassemia.

Metabolism of ketone bodies in pregnant sheep

Article

Full-text available

Dec 1982

1. A combination of isotope-dilution and arteriovenous-difference techniques was used to determine the significance of ketones to energy homoeostasis in fasted pregnant ewes. 2. There was incomplete interconversion of D(−) 3-hydroxybutyrate (3HB) and acetoacetate (AcAc) and therefore neither entry rate nor oxidation of total ketone bodies could be estimated by assuming circulating ketone bodies represent a single metabolic compartment. Total ketone body metabolism was satisfactorily summarized using a three-compartment model. In fasted pregnant ewes the mean entry rate of total ketones was 1 mmol/h per kg body-weight and of the ketones entering the circulation 87% were promptly oxidized to carbon dioxide accounting for 30% of the total CO a production. 3. Ketone bodies are readily utilized by hind-limb skeletal muscle such that if completely oxidized, 18±4 and 48±3% of the oxygen utilized could be accounted for in fed and fasted pregnant ewes respectively. For both 3HB and AcAc there was a hyperbolic relationship between utilization and arterial concentration. The apparent Michaelis constant ( K m ) values were 0·55 and 1–42 mM respectively and the maximum velocity ( V max ) 2·9 and 5·6 mmol/h per kg muscle. The arterial concentration of AcAc is always below the K m value and this limits the utilization rate. The D(−) 3HB concentration, however, may surpass that required for maximum utilization and ketoacidosis may be a consequence of this. 4. A two-compartment model was used to analyse ketone body metabolism by hind-limb skeletal muscle. The results suggested substantial intercon version and production of AcAc and 3HB. 5. The pregnant uterus utilized 3HB which if completely oxidized accounted for 12±2 (fed) and 25±4 (fasted) % of its O 2 consumption. At least 64% of the net 3HB utilized was oxidized. AcAc was not utilized in significant quantities.

Lipid membrane peroxidation in beta-thalassemia major

Article

Mar 1976

Effects of Opuntia humifusa Supplementation on Lipid Peroxidation and SOD Protein Expression in the Liver, Kidney, and Skeletal Muscle of Rats Fed a High-fat Diet

Article

Jul 2012

This study was conducted to investigate the effects of Opuntia humifusa supplementation on lipid peroxidation and superoxide dismutase (SOD) protein expression at resting state in various organs of rats fed a high-fat diet. Sixteen Sprague-Dawley male rats, 6 weeks of age, were randomly divided into two groups: a control diet group (CG, n

Reactive oxygen species-dependent signaling regulates cancer

Article

Aug 2009
CELL MOL LIFE SCI

Historically, it has been assumed that oxidative stress contributes to tumor initiation and progression solely by inducing genomic instability. Recent studies indicate that reactive oxygen species are upregulated in tumors and can lead to aberrant induction of signaling networks that cause tumorigenesis and metastasis. Here we review the role of redox-dependent signaling pathways and transcription factors that regulate tumorigenesis.

The effects of ketogenic diet on oxidative stress and antioxidative capacity markers of Taekwondo athletes

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