Monday, November 11, 2013

Health Research Recap (Week of 11/4/2013)

Researchers found that improved blood glucose control from gastric bypass surgery is related to increases in glucagon-like peptide 1(GLP-1).  It's often been reported that the rapid improvements in weight and blood glucose control from gastric bypass surgery are due to changes in the gut microbiome, the teeming zoo of bacteria found in the digestive tract.  Earlier studies have shown that the gut microbiota communicate with the brain by helping regulate hormone secretion from cells in the gut, including GLP-1.  This new study seems to add more support for changes in the gut microbiome being a key factor in the success of gastric bypass surgery.

Add colon cancer to the growing list of diseases associated with an altered gut microbiome.  Another study on gut microbes found a link between gut bacteria and tumor formation.  Transferring the gut microbes from mice with colon cancer to mice that were microbe free more than doubled the number of tumors compared to mice given a healthy microbiota.  Scientists have know for a long time that inflammation played a major role in colon cancer, this new study shows that inflammation and an altered gut microbiome both play a role.  It appears that inflammation is the fire, and a change in the gut microbiota is the gasoline that makes the fire burn out of control.

Another study identified the gene by which this process may occur.  The enzyme HDAC3 helps regulate genetic expression and the gene that codes for it has long been thought to be a tumor suppressor gene.  It turns out that mice bred without the HDAC3 gene had increased inflammation, poorer intestinal health, lacked certain antimicrobial cells, and had a different microbiome than healthy mice.  Furthermore, mice without the HDAC3 gene that were also germ free had healthy intestines.  It seems that this gene helps regulate the microbial population in the gut, and in turn that population helps control cellular behavior including inflammation.

In other gut news, researchers have found a link between the microbial community of the gut and rheumatoid arthritis.  Researchers found an increase in abundance of the bacterial strain Prevotella Corpi in people recently diagnosed with rheumatoid arthritis when compared to healthy controls and people with chronic, controlled rheumatoid arthritis.  Furthermore, the P. Corpi extracted from the patients recently diagnosed with rheumatoid arthritis was distinctly different than the P. Corpi from healthy individuals.  While this study only shows a relationship and doesn't show whether increased P.  Corpi causes rheumatoid arthritis or vice versa, there is a huge amount of evidence showing a clear link between gut health and systemic autoimmune diseases including rheumatoid arthritis.

On the pharmaceutical front, researchers have identified a class of drugs that have the potential to help treat inflammatory bowel diseases such as Crohn's Disease and colitis.  The new class of drugs work by helping turn down inflammation caused by low levels of oxygen in the gut.  If these drugs are used in an acute manner to help control inflammation that has become out of control in order to restore healthy function to the gut I can see them being very effective coupled with dietary change and other therapies including a fecal transplant.  If they are used chronically to subsidize poor behavior, which seems to be the tact most people take, I don't see them being very effective at all.

In autism news, a study looking at gut health and autism found children with autism are far more likely to experience GI problems than kids without it.  In addition, those with a higher severity of stomach issues had more severe symptoms of autism including irritability, social withdrawal, and hyperactivity.

Another study on autism found that breastfeeding may protect against autism by providing increased levels of insulin-like growth factor(IGF).  A review by the researchers found low levels of IGF to be a potential predictive test that could anticipate autism in children.  If a newborn is found to have low levels of IGF, the researchers believe increasing the length of breastfeeding can provide supplemental IGF to the child to help them develop properly.

Swinging over to obesity news, another study implicates obesity in the development of early onset puberty in girls.  While the study didn't look at causation, it found a fairly strong relationship between body mass index and early onset puberty.  When we look at what happens when people overeat, we see an increase in total daily energy expenditure even without increased physical activity.  Rather than looking at your body as a machine that burns the fuel you put in to it and stores the excess as fat, it seems that once the body meets it's energy needs, it certainly stores fat, but once a certain threshold is met it also decreases efficiency and burns more calories than it needs.  I believe the mechanism here is that it actually speeds up the aging process.  Not only will these girls go through puberty early, they will age faster overall.

A study looking at sleep duration and calorie consumption found that the longer kids sleep, the lower their calorie consumption is.  Kids slept for their normal amount of time for 1 week, then randomized to either more or less sleep for another week and performed the other one in the third week.  During the week the kids increased their sleep they ate 134 fewer calories a day, lost a half a pound, and had improved metabolic risk factors for obesity.

When compared to resistance training, aerobic exercise has a greater impact on improving metabolic risk factors associated with diabetes and obesity in obese girls.  If you are going to choose one over the other it may make more sense for girls to perform aerobic exercise over resistance training, but most studies show performing both provides the best results as they work through different mechanisms.

In brain news, elevations in brain magnesium levels prevented and reversed cognitive impairment in mice with Alzheimer's disease.  While this certainly doesn't mean low magnesium levels cause Alzheimer's in humans, the fact that the American diet coupled with coffee and alcohol consumption leads to low magnesium levels makes it a good idea to make sure you are getting sufficient magnesium on a regular basis.  The RDA for magnesium is 400mg for women and 420mg for men.

A diet high in wild blueberries may help prevent metabolic syndrome and cardiovascular disease.  The polyphenols in wild blueberries have been known to provide many health benefits.  In a study on obese mice, the polyphenols in wild blueberries helped improve blood vessel function and improve blood pressure.  Other studies from the same authors have found an anti-inflammatory effect as well as improvements in genetic expression in mice fed wild blueberries in their diet.  How you prepare the blueberries is important, another study found baking blueberries reduces their polyphenol content.