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A Large Randomized Trial: Effects of Mindfulness-Based Stress Reduction (MBSR) for Breast Cancer (BC) Survivors on Salivary Cortisol and IL-6.
Lengacher, CA, Reich, RR, Paterson, CL, Shelton, M, Shivers, S, Ramesar, S, Pleasant, ML, Budhrani-Shani, P, Groer, M, Post-White, J, et al
Biological research for nursing. 2019;21(1):39-49
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Breast cancer survivors (BCS) often experience physiological and psychological stressors related to their diagnosis and treatment, and a disruption of cortisol function can affect cancer risk and progression. Increased levels of the stress hormone cortisol and interleukin-6 (IL-6), a pro-inflammatory immune mediator, have been associated with acute and chronic stress levels. Mindfulness-Based Stress Reduction (MBSR) is a clinical stress-reducing program, which has been found to decrease psychological and physical symptoms associated with stress. The purpose of this randomised study, involving 299 BCS, was to evaluate the efficacy of MBSR in reducing cortisol and IL-6 levels, compared to a usual-care control treatment. Statistically significant reductions in cortisol levels were seen after the delivery of the MBSR program at both time points (week 1 and 6), and at week 6 only for IL-6. There was no significant difference in change in cortisol or IL6 levels over time between the MBSR and the usual-care groups. An association was observed between levels of IL-6 and psychological and physical symptoms and quality of life, but not for cortisol. The authors conclude that MBSR can alleviate the stress response in the short term for breast cancer survivors.
Abstract
Breast cancer survivors (BCS) often experience psychological and physiological symptoms after cancer treatment. Mindfulness-based stress reduction (MBSR), a complementary and alternative therapy, has reduced subjective measures of stress, anxiety, and fatigue among BCS. Little is known, however, about how MBSR affects objective markers of stress, specifically the stress hormone cortisol and the pro-inflammatory cytokine interleukin-6 (IL-6). In the present study, BCS ( N = 322) were randomly assigned to a 6-week MBSR program for BC or usual-care control. Measurements of cortisol, IL-6, symptoms, and quality of life were obtained at orientation and 6 weeks. Cortisol and IL-6 were also measured prior to and after the MBSR(BC) class Weeks 1 and 6. The mean age of participants was 56.6 years and 69.4% were White non-Hispanic. Most had Stage I (33.8%) or II (35.7%) BC, and 35.7% had received chemotherapy and radiation. Cortisol levels were reduced immediately following MBSR(BC) class compared to before the class Weeks 1 and 6 (Wilcoxon-signed rank test; p < .01, d = .52-.56). IL-6 was significantly reduced from pre- to postclass at Week 6 (Wilcoxon-signed rank test; p < .01, d = .21). No differences were observed between the MBSR(BC) and control groups from baseline to Week 6 using linear mixed models. Significant relationships with small effect sizes were observed between IL-6 and both symptoms and quality of life in both groups. Results support the use of MBSR(BC) to reduce salivary cortisol and IL-6 levels in the short term in BCS.
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Excessive Sugar Consumption May Be a Difficult Habit to Break: A View From the Brain and Body.
Tryon, MS, Stanhope, KL, Epel, ES, Mason, AE, Brown, R, Medici, V, Havel, PJ, Laugero, KD
The Journal of clinical endocrinology and metabolism. 2015;100(6):2239-47
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It is widely known that people eat to relieve stress. Rodent studies have shown that sugar consumption switches off activity in the networks that mediate the stress induced hypothalamic-pituitary-adrenal (HPA) autonomic nervous system. This study aimed to compare the effects of consuming drinks, sweetened with either sucrose or aspartame, on cortisol responses induced by stress. The researchers found that sucrose consumption was associated reduced stress induced cortisol, and a trend towards lower cortisol. Aspartame did not have the same effect. The Montreal Imaging Stress Task (MIST) was used to map areas of the brain associated with stress. It was found that sugar consumption caused a diminished response to MIST after two weeks of sucrose consumption, and cortisol was elevated after two weeks of aspartame. The study concluded that brain negative feedback pathways are affected by sugar, and consequently may make stressed individuals more reliant or addicted to sugar. In turn, this increases the likelihood of obesity and its associated chronic diseases.
Abstract
CONTEXT Sugar overconsumption and chronic stress are growing health concerns because they both may increase the risk for obesity and its related diseases. Rodent studies suggest that sugar consumption may activate a glucocorticoid-metabolic-brain-negative feedback pathway, which may turn off the stress response and thereby reinforce habitual sugar overconsumption. OBJECTIVE The objective of the study was to test our hypothesized glucocorticoid-metabolic-brain model in women consuming beverages sweetened with either aspartame of sucrose. DESIGN This was a parallel-arm, double-masked diet intervention study. SETTING The study was conducted at the University of California, Davis, Clinical and Translational Science Center's Clinical Research Center and the University of California, Davis, Medical Center Imaging Research Center. PARTICIPANTS Nineteen women (age range 18-40 y) with a body mass index (range 20-34 kg/m(2)) who were a subgroup from a National Institutes of Health-funded investigation of 188 participants assigned to eight experimental groups. INTERVENTION The intervention consisted of sucrose- or aspartame-sweetened beverage consumption three times per day for 2 weeks. MAIN OUTCOME MEASURES Salivary cortisol and regional brain responses to the Montreal Imaging Stress Task were measured. RESULTS Compared with aspartame, sucrose consumption was associated with significantly higher activity in the left hippocampus (P = .001). Sucrose, but not aspartame, consumption associated with reduced (P = .024) stress-induced cortisol. The sucrose group also had a lower reactivity to naltrexone, significantly (P = .041) lower nausea, and a trend (P = .080) toward lower cortisol. CONCLUSION These experimental findings support a metabolic-brain-negative feedback pathway that is affected by sugar and may make some people under stress more hooked on sugar and possibly more vulnerable to obesity and its related conditions.
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No effect of caloric restriction on salivary cortisol levels in overweight men and women.
Tam, CS, Frost, EA, Xie, W, Rood, J, Ravussin, E, Redman, LM
Metabolism: clinical and experimental. 2014;63(2):194-8
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Alterations in normal cortisol patterns have been observed in people who are obese. The effect of weight loss on cortisol levels, a measure of hypothalamic pituitary adrenal (HPA) activity, in overweight individuals is not known. The aim of this study was to test the hypothesis that 6 months of moderate caloric restriction would alter morning and diurnal salivary cortisol levels. Thirty-five overweight adults (average BMI 27.8 kg/m2) took part in this randomised control trial. Participants were assigned to either calorie restriction (CR: 25% reduction in energy intake), calorie restriction+exercise (CR+EX: 12.5% reduction in energy intake+12.5% increase in exercise energy expenditure) or control (healthy weight-maintenance diet) for 6 months. Salivary cortisol was measured at 8:00, 8:30, 11:00, 11:30, 12:30, 13:00, 16:00 and 16:30. Morning cortisol was defined as the mean cortisol concentration at 08:00 and 08:30. Diurnal cortisol was calculated as the mean of the 8 cortisol measures across the day. Across all groups, higher morning and diurnal cortisol levels were associated with impaired insulin sensitivity. There was no significant effect of group, time or sex on morning or diurnal cortisol levels. The authors concluded that a 10% weight loss with a 25% CR diet alone or with exercise did not impact morning or diurnal salivary cortisol levels in overweight individuals. Their findings suggest that prolonged restriction of energy intake is not perceived by the body as a stressor, and therefore CR may present a viable intervention.
Abstract
OBJECTIVE The effect of weight loss by diet or diet and exercise on salivary cortisol levels, a measure of hypothalamic pituitary adrenal activity, in overweight individuals is not known. The objective was to test the hypothesis that 24 weeks of moderate caloric restriction (CR) (25%) by diet or diet and aerobic exercise would alter morning and diurnal salivary cortisol levels. DESIGN AND SETTING Randomized control trial in an institutional research center. PARTICIPANTS Thirty-five overweight (BMI: 27.8±0.7 kg/m(2)) but otherwise healthy participants (16 M/19 F). INTERVENTION Participants were randomized to either calorie restriction (CR: 25% reduction in energy intake, n=12), calorie restriction+exercise (CR+EX: 12.5% reduction in energy intake+12.5% increase in exercise energy expenditure, n=12) or control (healthy weight-maintenance diet, n=11) for 6 months. MAIN OUTCOME MEASURE Salivary cortisol measured at 8:00, 8:30, 11:00, 11:30, 12:30, 13:00, 16:00 and 16:30. Morning cortisol was defined as the mean cortisol concentration at 08:00 and 08:30. Diurnal cortisol was calculated as the mean of the 8 cortisol measures across the day. RESULTS In the whole cohort, higher morning and diurnal cortisol levels were associated with impaired insulin sensitivity (morning: P=0.004, r(2)=0.24; diurnal: P=0.02, r(2)=0.15). Using mixed model analysis, there was no significant effect of group, time or sex on morning or diurnal cortisol levels. CONCLUSION A 10% weight loss with a 25% CR diet alone or with exercise did not impact morning or diurnal salivary cortisol levels.
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Sleep restriction for 1 week reduces insulin sensitivity in healthy men.
Buxton, OM, Pavlova, M, Reid, EW, Wang, W, Simonson, DC, Adler, GK
Diabetes. 2010;59(9):2126-33
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Short sleep duration is associated with an increased risk of many chronic diseases including diabetes, however the effects of sleep restriction on insulin sensitivity have not yet been established. The aim of study was to assess the effects of decreased sleep duration on insulin sensitivity in a controlled environment. This 12-day inpatient study included 20 healthy men who were randmoised to receive a wakefulness-promoting drug, modafinil, or placebo during the sleep restriction phase. This study showed that sleep restriction for one week significantly reduces insulin sensitivity. These findings raise concerns about chronic insufficient sleep on the development of metabolic diseases and promote further research into these effects.
Abstract
OBJECTIVE Short sleep duration is associated with impaired glucose tolerance and an increased risk of diabetes. The effects of sleep restriction on insulin sensitivity have not been established. This study tests the hypothesis that decreasing nighttime sleep duration reduces insulin sensitivity and assesses the effects of a drug, modafinil, that increases alertness during wakefulness. RESEARCH DESIGN AND METHODS This 12-day inpatient General Clinical Research Center study included 20 healthy men (age 20-35 years and BMI 20-30 kg/m(2)). Subjects spent 10 h/night in bed for >or=8 nights including three inpatient nights (sleep-replete condition), followed by 5 h/night in bed for 7 nights (sleep-restricted condition). Subjects received 300 mg/day modafinil or placebo during sleep restriction. Diet and activity were controlled. On the last 2 days of each condition, we assessed glucose metabolism by intravenous glucose tolerance test (IVGTT) and euglycemic-hyperinsulinemic clamp. Salivary cortisol, 24-h urinary catecholamines, and neurobehavioral performance were measured. RESULTS IVGTT-derived insulin sensitivity was reduced by (means +/- SD) 20 +/- 24% after sleep restriction (P = 0.001), without significant alterations in the insulin secretory response. Similarly, insulin sensitivity assessed by clamp was reduced by 11 +/- 5.5% (P < 0.04) after sleep restriction. Glucose tolerance and the disposition index were reduced by sleep restriction. These outcomes were not affected by modafinil treatment. Changes in insulin sensitivity did not correlate with changes in salivary cortisol (increase of 51 +/- 8% with sleep restriction, P < 0.02), urinary catecholamines, or slow wave sleep. CONCLUSIONS Sleep restriction (5 h/night) for 1 week significantly reduces insulin sensitivity, raising concerns about effects of chronic insufficient sleep on disease processes associated with insulin resistance.