Research Extracts: Exercise and cancer; Spouse and diabetes; Astaxanthin and aging; M. vaccae and stress
Welcome to the fifth edition of Thorne’s Research Extracts. This is Thorne’s monthly research update on diet, nutrient, botanical, and lifestyle approaches to good health. Knowing that busy practitioners can’t always focus on the latest research, our medical team of NDs, MDs, PhDs, RDs, and MS (Biol) has summarized the essence of the very most interesting studies.
In this issue discuss: (1) exercise and cancer mortality; (2) spousal weight and diabetes risk; (3) astaxanthin and skin aging; and (4) the microbiome and stress.
Exercise and cancer mortality
Because adult survivors of childhood cancers tend to have a higher mortality risk compared to the general population, this study’s objective was to determine whether exercise can reduce this risk.
Data was collected and analyzed from 15,450 adult cancer survivors who had been diagnosed before age 21, had enrolled in the Childhood Cancer Survivor Study between 1970 and 1999, and had been followed up through December 31, 2013.
Based on questionnaire data provided by the study participants and after adjusting for chronic health conditions and treatment exposures, a significant inverse association was observed across quartiles of exercise and all-cause mortality.
Increased exercise over eight years was associated with a 40% reduction in all-cause mortality compared with only maintaining low exercise. This study suggests that vigorous exercise in early adulthood and increased exercise over eight years is associated with lower mortality risk in adult survivors of childhood cancers.
Contributed by Mario Roxas, ND
- Scott J, Li N, Liu Q, et al. Association of exercise with mortality in adult survivors of childhood cancer.
- JAMA Oncol 2018 June 3. doi:10.1001/jamaoncol.2018.2254
Is your spouse’s weight a risk factor for you getting type 2 diabetes?
In a longitudinal study, Danish researchers analyzed data from 3,649 men and 3,478 women that represented their own and their spouse’s diabetes status and cardiometabolic risk factors (BMI, waist circumference (WC), blood pressure, and lipid levels).
Looking at exposures assessed by cardiometabolic risk factors and outcomes by incidence of type 2 diabetes, the researchers found spousal BMI and WC were both associated over time with onset of type 2 diabetes, although it wasn’t the case for both men and women.
When adjusting for the man’s obesity, in a relationship where the wife is overweight or obese, the risk of the husband developing type 2 diabetes increases significantly. A wife with a BMI that is 5 kg/m2 higher than her husband was associated with a 21% increased risk of developing type 2 diabetes.
However, a husband’s BMI was not associated with the incidence of type 2 diabetes in his wife, even after adjusting for the woman’s obesity level. Of the cardiometabolic risk factors, WC had similar findings to those for BMI in both instances.
The researchers wanted to express the sex-specific effects of spousal obesity on diabetes risk – a disease that is growing annually and for which researchers believe there are numerous undiagnosed cases. The study’s results suggest a couples-focused approach might be best for detecting type 2 diabetes. The researchers also noted this information is especially important for men, since statistically men are less likely than women to obtain health checks.
Contributed by Laura Kunces, PhD
- Nielsen J, Hulman A, Witt D. Spousal cardiometabolic risk factors and incidence of type 2 diabetes: a prospective analysis from the English Longitudinal Study of Ageing. Diabetologia 2018;61:1572-1580.
Can astaxanthin protect skin from UV-induced aging?
In a double-blind, placebo-controlled trial, 23 individuals were given either 4 mg astaxanthin or placebo daily for nine weeks. Minimal erythemal dose (MED; the shortest exposure to UV light needed to cause reddening of the skin) was determined before and after treatment. In addition, UV-induced changes to skin moisture and transdermal water loss were assessed.
Astaxanthin appeared to exert a protective effect in several ways. MED in the astaxanthin group increased compared to the placebo group, indicating decreased sensitivity to UV irradiation. This group also experienced decreased loss of skin moisture in irradiated areas compared to the individuals in the placebo group.
Subjective improvements were also assessed by a visual analog scale that demonstrated improved skin texture and less dry skin in the astaxanthin group. The authors concluded that astaxanthin can help maintain healthy skin in healthy individuals.
Contributed by Kathi Head, ND
- Ito N, Seki S, Ueda F. The protective role of astaxanthin for UV-induced skin deterioration in healthy people – a randomized, double-blind, placebo-controlled trial. Nutrients 2018 Jun 25;10(7). pii: E817. doi: 10.3390/nu10070817
M. vaccae vaccination might immunize against stress effects in the brain
Neuroinflammatory responses might be linked to the incidence of disorders such as anxiety and depression. Stress is a known trigger for chronic, low-level inflammation. Microbe-based immune-regulation might hold a key to regulating this outcome.
Previous experiments have shown an anti-inflammatory effect derived from a vaccination of heat-killed Mycobacterium vaccae. Expanding on those studies, investigators at the University of Colorado Boulder looked at the effects of M. vaccae inoculation in the central nervous system of rats by assessing inflammatory and stress-response markers.
Adult male Sprague Dawley rats were inoculated with heat-killed M. vaccae or placebo control at 1, 2, and 3 weeks before exposure to a stressor (inescapable tailshock). The rats receiving placebo showed expected stress responses, including microglial priming (specifically in the hippocampus), elevated serum corticosterone, and reduced juvenile social exploration behavior (JSE; investigation of a new juvenile introduced into the cage). Inoculation with M. vaccae blocked these stress-induced changes.
Levels of tested markers appeared normal in M. vaccae treated rats, and JSE behavior was unchanged in the stressed rats receiving M. vaccae pre-treatment. M. vaccae did not alter corticosterone levels. Overall these findings suggest the potential for M. vaccae immunization to generate an anti-inflammatory pattern, preventing stress-priming of neuroinflammation and reducing risk for neurological disruptions, such as anxiety or depression.
Contributed by Sheena Smith, MS (Biol)
- Frank M, Fonken L, Dolzani S, et al. Immunization with Mycobacterium vaccae induces an anti-inflammatory milieu in the CNS: attenuation of stress-induced microglial priming, alarmins and anxiety-like behavior. Brain Behav Immun 2018 May 26. pii: S0889-1591(18)30196-X. doi: 10.1016/j.bbi.2018.05.020.