Study under review: Vitamin B12 modulates the transcriptome of the skin microbiota in acne pathogenesis
The composition of bacteria in certain parts of the body, known as the microbiome, has been linked to human health and disease over the past decade, and has been discussed quite a bit in several past issues of Study Deep Dives. One common thread of microbiome studies is that they tend to look at how changes in the composition of the microbiome correspond to changes in health. Some bacteria overgrow while some undergrow, which can be correlated with health and disease. But one relatively unexplored area is the specific molecular mechanisms through which the microbiome impacts health.
Acne is a good condition (as far as conditions can be “good”) to study changes in the microbiome and their role in disease for a few reasons. The skin microbiome’s contribution to acne has been studied for a relatively long time compared to the microbiome residing in other areas of the body. Those studies have led researchers to suspect that one species of bacterium, Propionibacterium acnes, is one of the main contributors to acne, which further simplifies matters. It should be noted, though, that the exact role of P. acnes is not entirely clear.
Indeed, P. acnes is found on both healthy human skin and in acne, so why do some people break out while others don’t? The authors of the current paper thought that modern molecular techniques had a decent chance of providing an answer to this question. While P. acnes is present on both healthy and acne-afflicted skin, there may be differences in the expression levels of the genes in bacteria living on the skin (known as “the metatranscriptome”, which is shown in Figure 1). Differences in expression by P. acnes in particular (its transcriptome) between different people could help explain the development of acne, given a seemingly similar microbiome composition. These differences in gene expression levels were what the authors set out to explore.
Acne is caused in part by the bacterium Propionibacterium acnes. However, this bacterium lives on both healthy and acne-prone skin. So why do some people break out and some don’t? The authors of this paper looked at what genes were expressed by skin bacteria in order to find out.
Other Articles in Issue #10 (August 2015)
Put down the apple and have some chedda
Although both cheese and meat are lumped into the “watch out!” category in hearthealth recommendations, dairy products often show neutral or positive associations with cardiovascular health. But how do cheese-rich diets fare in randomized trials when compared to other diets? This trial tested three diets against each other in a highly controlled fashion: a cheese diet, meat diet, and high-carb diet.
All up in your krill: The story on krill
Oil thus far has been fairly simplistic: it’s better than fish oil and more expensive. But there’s a reason why you can’t draw conclusions based off few studies, and successful results in one condition don’t apply to other conditions. This trial gives some of the first pieces of evidence for possible negative metabolic effects of krill. oil.
Omega-3: kid-tested, mom approved?
While heart health gets much of the attention for fish oil benefits (which, incidentally, are often overstated), outcomes in children typically show more promise. This study, involving children and their parents living on the island of Mauritius, explored possible behavioral benefits to fish oil supplementation. And not just the childrens’ behavior, but the parents’ as well!
Priming the pump: carb levels for endurance exercise
If you run, cycle, or do anything long and sweaty, then you already know that carb intake is especially important for endurance activity. But recommended intakes range from around 30-60 grams, which is pretty broad. This trial can help you get to a more specific number, and possibly perform better.
A thorough trial of carb intake for diabetes
There are few conditions where carbs play as direct of a role as in type 2 diabetes. Yet the recommended carb intake levels for this condition aren’t so different than for the general population. That may change at some point, due to trials like this one, which is more highly controlled and thorough than previous lower-carb & diabetes studies.
- Interview: Elke Nelson PhD
- Interview: Marguerite McDonald, MD
Wellness, Not Weight
By Cristen Harris, PhD
Salt in the wound
Science and mystery often go hand in hand, and this is a perfect example: when you have a skin infection, you tend to have more salt in the infected skin. But why is that? Well, where there’s smoke, there’s fire. The salt is probably doing something in regards to immune response, and it’s possible that how much salt you eat could also play a role. Resist the urge to skip to the end of this mystery -- the buildup is worth it.
Carbs-protein or protein-carbs …
Does food order matter? Grandma always said “You have to eat your vegetables first if you want dessert!”. If you substitute “carbs” in for dessert, grandma might have hit another one out of the park. It’s possible that simply switching the order of what you eat might benefit blood sugar control, which would be a relatively easy way to address the thorny public health issue of type 2 diabetes