Every week there are numerous scientific studies published. Here’s a look at some of the more interesting ones.

Dietary Supplements Don’t Improve Heart Disease or Add to Longevity

Johns Hopkins Medical researchers analyzed the data from 277 clinical trials using 24 different interventions to look at the effects of vitamins, minerals and other nutrient supplements and whether they were linked to longer life or protected from heart disease. Except for a few cases, they did not. The research was published in the journal Annals of Internal Medicine.

“Our analysis carries a simple message that although there may be some evidence that a few interventions have an impact on death and cardiovascular health, the vast majority of multivitamins, minerals and different types of diets had no measurable effect on survival or cardiovascular disease risk reduction,” stated lead author Safi U. Khan, assistant professor of Medicine at West Virginia University.

The exceptions were a low-salt diet, omega-3 fatty acid supplements, and possibly folic acid supplements. They also found that combinations of calcium and vitamin D appear linked to a slight increased risk of stroke.

“The panacea or magic bullet that people keep searching for in dietary supplements isn’t there,” stated senior author Erin D. Michos, associate director of preventive cardiology at the Ciccarone Center for the Prevention of Cardiovascular Disease and associate professor of medicine at Johns Hopkins. “People should focus on getting their nutrients form a heart-healthy diet, because the data increasingly show that the majority of healthy adults don’t need to take supplements.”

On the other hand, the supplements and diets were not generally associated with any harm.

A Cell Type that Can Heal Cardiac Tissue

Scientists with the University of Calgary identified a new cell population in the pericardial fluid inside the sac around the heart. The cell type, a Gata6+ pericardial cavity macrophage, heals injured heart cells in mice. The cell was identified in the pericardial fluid of a mouse with heart injury and later in humans. The researchers are now focused on how these cells might be stimulated to assist in heart repair.

Gut Infection Related to Parkinson’s Disease?

Some forms of Parkinson’s disease appear to be autoimmune diseases. New research found that a gut infection can lead to pathology similar to Parkinson’s disease in a mouse model. Parkinson’s is caused by the progressive death of dopaminergic neurons in the brain. What causes the death is unknown. Some theories point to toxic elements. A group in Montreal studied gut infections in a mouse model. In their research, mice without a gene linked to the human disease triggered PD-like symptoms over time. This suggests the possibility of that an immune reaction is linked to the disease.

Alzheimer’s Gene Linked to Cognition Issues Earlier in Life

The APOE4 gene was one of the first genes associated with Alzheimer’s disease. APOE codes for a protein, apolipoprotein E, which packages cholesterol and other fats for transportation through the bloodstream. APOE4 is found in about 15% of the population and carriers have about three times higher risk of developing late-onset Alzheimer’s. New research suggests carriers with APOE4 may affect cognition earlier in life. A researcher found that carriers had lower IQ test scores during childhood and adolescence, and the effect was stronger in girls than boys.

Molecular Link Between Diabetes and Arterial Constriction

One of the major complications of diabetes is narrowing of the blood vessels. This constriction increases the risk of heart disease and stroke. Researchers at UC Davis Health identified a new molecular link that could potentially lead to new diabetes treatments and potential cardiovascular therapies. The research examined the relationship between PKA and adenylyl cyclase (AC), an enzyme involved in the production of cyclic AMP (cAMP), a cellular messenger that plays a critical role in vascular cell function. The researchers found that AC5, which mediated cAMP and PKA activation, caused increased calcium channel activity, resulting in narrowing of the blood vessels. They also discovered that AC5 was required for blood-vessel constriction during diabetes.

Paleo Diet Linked to Heart Disease Biomarker

Researchers out of Australia conducted a study on 44 people on the so-called paleo diet and 47 on a traditional Australian diet. They found that the amount of trimethylamine-n-oxide (TMAO) in the paleo diet cohort was twice as high as that found in the traditional diet. TMAO is closely linked to heart disease. They believe the reason TMAO is so high is the lack of whole grains in the diet.