Effect of Modest Caloric Restriction on Oxidative Stress in Women, a Randomized Trial

<div><h3>Objectives</h3><p>It is not established to what extent caloric intake must be reduced to lower oxidative stress in humans. The aim of this study was to determine the effect of short-term, moderate caloric restriction on markers of oxidative stress and inflammation in overweight and obese premenopausal women.</p> <h3>Materials/Methods</h3><p>Randomized trial comparison of 25% caloric restriction (CR) or control diet in 40 overweight or obese women (body mass index 32±5.8 kg/m²) observed for 28 days and followed for the next 90 days. Weight, anthropometry, validated markers of oxidative stress (F₂-isoprostane) and inflammation (C-reactive protein), adipokines, hormones, lipids, interleukins, and blood pressure were assessed at baseline, during the intervention, and at follow-up.</p> <h3>Results</h3><p>Baseline median F₂-isoprostane concentration (57.0, IQR = 40.5–79.5) in the CR group was 1.75-fold above average range for normal weight women (32.5 pg/ml). After starting of the caloric restriction diet, F₂-isoprostane levels fell rapidly in the CR group, reaching statistical difference from the control group by day 5 (median 33.5, IQR = 26.0–48.0, P<0.001) and remained suppressed while continuing on the caloric restriction diet. Three months after resuming a habitual diet, concentrations of F₂-isoprostane returned to baseline elevated levels in ∼80% of the women.</p> <h3>Conclusions</h3><p>Oxidative stress can be rapidly reduced and sustained through a modest reduction in caloric intake suggesting potential health benefits in overweight and obese women.</p> <h3>Trial Registration</h3><p>Clinicaltrials.gov <a href="http://clinicaltrials.gov/ct2/show/NCT00808275">NCT00808275</a></p> </div

Comparison of reported average (28 days) intake of protein, sodium, and potassium with the corresponding biological markers in urine in the caloric restriction (CR) diet group.

<p>Data are presented as means ± s.d.</p>a<p>Average daily intakes of protein, sodium, and potassium assessed by NDSR (Nutrition Diet System, St. Paul, MN).</p>b<p>Excretion measured from 4 weekly 24-hour urine collections. Protein = urinary nitrogen *7.72 (18), Potassium = urinary potassium *0.77 (19).</p>c<p>Comparison of ratios of intake to excretion; one sample t-test.</p

Body weight, BMI, and body fat mass at baseline, end of intervention (Day 29), and follow-up (Day 119).

<p>Data are presented as median (interquartile range - IQR).</p><p>Abbreviations: CR diet, caloric restriction diet; BMI, body mass index (kg/m²).</p>a<p>Wilcoxon rank sum test for differences between Control and CR diets.</p

CONSORT flow diagram.

<p>CONSORT flow diagram.</p

Median daily macro- and selected micro-nutrient intake in the caloric restriction (CR) and Control diet groups.

<p>Data are presented as median (interquartile range -IQR).</p>1<p>- different from Control diet, p<0.001, Wilcoxon rank sum test.</p><p>Daily multivitamin supplement was given during intervention Days 1–28 (Multi Complete, Nature Made, Mission Hills, CA) composition: vitamin A - 2 500 IU, vitamin D₃ - 1000 IU, vitamin E - 50 IU, vitamin C - 180 mg, vitamin B₁ - 15 mg, vitamin B₂ - 1.7 mg, niacin - 20 mg, vitamin B₆ - 2 mg, folate - 400 mcg, vitamin B₁₂ - 6 mcg, calcium 162 mg, magnesium - 100 mg, iron - 18 mg, selenium - 70 mcg.</p

Multivariable linear regression results for change in F2-isoprostane serum levels during the 28-day dietary intervention.

<p>Effect shown is the F₂-isoprostane ratio. BMI - body mass index; CR diet- caloric restriction diet. Adjusted to: Day of intervention = 7, Group = CR.</p

Blood pressure, hormones, and lipids at baseline, end of intervention (Day 29), and follow-up (Day 119).

<p>Data are presented as median (interquartile range -IQR).</p><p>Abbreviations: LDL, low-density lipoprotein; HDL, high-density lipoprotein.</p>1<p>Wilcoxon rank sum test for differences between Control and CR diets.</p

Inflammatory markers at baseline, end of intervention (Day 29), and follow-up (Day 119).

<p>Data are presented as median (interquartile range - IQR). CR, caloric restriction diet.</p>1<p>Wilcoxon rank sum test for differences between Control and CR diets.</p

Differences in F₂-isoprostane (pg/mL) serum levels between caloric restriction (CR) and control groups at baseline (Day 0), during the intervention (Days 1 to 29), and follow-up (Days 42 and 119).

<p>Data are presented as median (interquartile range- IQR). CR diet, caloric restriction diet.</p>a<p>Wilcoxon rank sum test for differences between Control and CR diets.</p