Dietary carbohydrate intake and mortality study: validating a whole-food, plant-based diet

A study in the August publication of the Lancet aimed to investigate the association between carbohydrate intake and mortality.  The meta-analysis included 432,179 participants who were followed for a median of 25 years. The primary outcome was all-cause mortality.  Researchers also assessed whether the substitution of animal or plant sources of fat and protein for carbohydrate affected mortality.

P_WFPBBoth low carbohydrate consumption (<40%) and high carbohydrate consumption (>70%) conferred greater mortality risk than did moderate intake. However, results varied by the source of macronutrients: mortality increased when carbohydrates were exchanged for animal-derived fat or protein and mortality decreased when the substitutions were plant-based. Low carbohydrate dietary patterns favouring animal-derived protein and fat sources, from sources such as lamb, beef, pork, and chicken, were associated with higher mortality, whereas those that favored plant-derived protein and fat intake, from sources such as vegetables, nuts, peanut butter, and whole-grain breads, were associated with lower mortality, suggesting that the source of food notably modifies the association between carbohydrate intake and mortality.

Intermittent Fasting Confers Protection in CNS Autoimmunity by Altering the Gut Microbiota

A mouse study, published on the June issue of Cell Metabolism, shows that intermittent fasting (IF) ameliorated the clinical course and pathology of experimental autoimmune encephalomyelitis (EAE). EAE is the animal model used to study an inflammatory and demyelinating disease of the central nervous system, which is used to mimic human multiple sclerosis.  IF led to increased gut bacteria richness, enrichment of the Lactobacillaceae, Bacteroidaceae, and Prevotellaceae families and enhanced antioxidative microbial metabolic pathways. IF altered T-cells in the gut with a reduction of IL-17 producing T cells and an increase in regulatory T cells. Fecal microbiome transplantation from mice on IF ameliorated EAE in immunized recipient mice on a normal diet, suggesting that IF effects are at least partially mediated by the gut flora. In a pilot clinical trial in MS patients, intermittent energy restriction altered blood adipokines and the gut flora resembling protective changes observed in mice. In conclusion, IF has potent immunomodulatory effects that are at least partially mediated by the gut microbiome.

The study was conducted in collaboration by researchers at multiple universities in the U.S. and Italy.

Increased Aerobic Fitness Is Associated with Cortical Thickness in Older Adults with Mild Vascular Cognitive Impairment

A recent article published in the Journal of Cognitive Enhancement reviews a randomized controlled trial with 71 older adults with sub-cortical ischemic vascular cognitive impairment (SIVCI).

At trial completion, compared with the control group, participants in the aerobic training group showed significantly improved aerobic fitness, increased change in cortical thickness, and change in the right superior temporal gyrus thickness. Maintenance of cortical thickness was independently and significantly associated with improved processing speed performance on the digit symbol substitution test (DSST) over the 6-month trial.  The study concluded, a 6-month aerobic training program may promote cognitive outcomes in older adults with mild SIVCI by improving aerobic fitness capacity and maintaining cortical thickness.

Genetic Test Will Help Thousands of Breast Cancer Patients Avoid Chemo

Approximately 100,000 U.S. women each year who are diagnosed with the most common form of early breast cancer may be spared chemotherapy under a new precision medicine approach, according to a landmark study — Trial Assigning Individualized Options for Treatment (Rx) or TAILORx. TAILORx, which was sponsored by the National Cancer Institute, enrolled over 10,000 women with early-stage breast cancer across the U.S. and five additional countries.

When a physician suspects breast cancer, he/she will test biopsied cells for specific molecules found in tumors.  The test will typically look for characteristics that include what receptors, if any, are present on the surface of detected cancer cells. Hormone receptors are proteins located in and around breast cells. These receptors signal cells — both healthy and cancerous — to grow. In the case of breast cancer, the hormone receptors tell the cancer cells to grow uncontrollably, and a tumor results. Some breast cancers have high levels of another growth-promoting protein called HER2/neu. If a tumor has this property, it is called HER2/neu-positive.  The axillary nodes are a group of lymph nodes located in the armpit region of the body. A prognosis is better when the cancer is only in the breast, and the lymph nodes are not affected.  Women recently diagnosed with estrogen-receptor and/or progesterone-receptor positive, HER2/neu-negative breast cancer that had not yet spread to the lymph nodes were eligible for the study.

The majority of women with early-stage breast cancer have been advised to receive chemotherapy in addition to radiation and hormonal therapy. It was determined that a molecular profiling test, the Oncotype DX Breast Recurrence Score® genomic test, which analyzes 21 genetic markers, could reveal the unique biology of a tumor. This genetic test will more precisely inform physicians and their patients about who will, or will not, benefit from the addition of chemotherapy.

“By stratifying these breast cancer patients and finding that only those with the highest risk of recurrence need to have chemotherapy based on their tumor genetics, TAILORx shows great potential to ensure more gentle treatment without compromising its effectiveness,” said Professor Arnie Purushotham, Senior Clinical Adviser at Cancer Research UK.

For more information: National Cancer Institute TAILORx Study

Short Sleep May be a Newly Identified Modifiable Risk Factor for Obesity

A recent study published in the American Journal of Clinical Nutrition finds that short sleep duration may be a newly identified modifiable risk factor for obesity.

Experimental evidence investigating the effects of sleep deprivation on insulin resistance, glucose levels, appetite hormone dysregulation, and weight gain has indicated that poor sleep is potentially detrimental to overall health.

image credit: Mariah Aro Sharp @mightymooseart

The aim of this research was to assess the feasibility of sleep extension (SE) by using a behavioral change approach through sleep hygiene under free-living conditions in healthy adults who are habitually short sleepers. If it was shown to be feasible to extend sleep duration in this population, it was hypothesized that SE would lead to changes in secondary outcome measures that are conducive to weight maintenance.  To test this hypothesis, the secondary aim of the study was to conduct a pilot investigation on the effects of SE on dietary intake and indicators of energy balance.

The study results show that short sleepers were able to extend their sleep through personalized behavior modification. Sleep extension led to reduced free sugar intakes and may be a viable strategy that helps to limit excessive sugar consumption in an obesity-promoting environment.

Interview: Gut bacteria leads to child obesity, says Mexican researcher

Mexican scientists have found evidence that bacteroidetes, firmicutes and other gut bacteria can lead to obesity in children.  “Through a study, we were able to verify that there is an imbalance of bacteria, that is to say that these microbes are abundant in the digestive tract of a child suffering from obesity, compared to minors that are at their ideal weight,” said Jaime Garcia Mena, a scientist at Mexico’s Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV). The findings are part of a study, called the “Genetics of obesity in infancy and adolescence,” that was undertaken to help understand Mexico’s growing problem of obese youngsters.  Garcia, who works in CINVESTAV’s department of genetics and molecular biology, said nutrition plays an important part in regulating gut bacteria and determining weight, with children who consume more meats, simple sugars and starches developing a digestive environment that favors obesity. (Published on XinhuaNet.)

Personalizing Physical Exercise

The beneficial effects of physical activity for the prevention and management of several chronic diseases are widely recognized. Mathematical modeling of the effects of physical exercise in body metabolism and in particular its influence on the control of glucose homeostasis is of primary importance in the development of eHealth monitoring devices for personalized medicine. Formulating a model describing the metabolic responses to a physical exercise session is a challenging task since the effects vary depending on its intensity, duration, modality and are also dependent on the subjects’ physical characteristics (e.g. age, gender, body weight, fitness status). To date, only a few mathematical models have aimed at this specific purpose and none of the existing computational models had been able to provide this level of “personalization.”  

Italian researchers have now developed a whole-body computational model of the effects of a bout of physical exercise on metabolic homeostasis. “Modeling the influence of physical exercise on the control of glucose homeostasis is of primary importance in the understanding of how physical activity prevents disease and improves health outcomes…” stated the study’s lead author, Maria Concetta Palumbo of the National Research Council of Italy. (PLOS Computational Biology)

New Study Provides Insight into Blood Signatures of Inflammation

A new study from Boston University Schools of Medicine (BUSM) and Public Health (BUSPH) has identified patterns of inflammation in the blood and adipose tissue. Researchers found six cytokines (immune cell signaling proteins) signature patterns involving 16 cytokines.  (Inflammation is characterized by an interplay between pro- and anti-inflammatory cytokines.) These findings were validated in cohort studies and are believed to be significant for clinical identification of those at risk for type 2 diabetes and cardiovascular disease. Read more.

The National Institute of Health’s “All of Us” Research Program

The NIH (National Institute of Health) is recruiting 1 million people to share their DNA and 10 years of health history.  The massive biobank effort, known as the Precision Medicine Initiative, was first announced by President Obama in his 2015 State of the Union address.  Congress authorized $1.45 billion over 10 years for the project. The initiative is a move toward expanding our understanding of the intimate link between genetics, lifestyle, and the environment.  The program’s long-term goal is to expand access to precision medical care. Most biomedical research to date has been done on non-rural, educated, white males. One of the fundamental goals of the NIH’s research program is to get participants that are underrepresented in biomedical research. To participate in the program, any U.S. resident over 18 can signup at the All of Us Research Program. Official enrollment began May 6, 2018.