Studies uncover 500 “hidden” microbes in the gut

Over the last few years, scientists have found that the microbes hosted in the digestive tract (the gut microbiota or gut flora) perform key functions for health. Digestion, immunity and even mental health are extremely dependent on tasks carried out by the gut bacteria.

Now, two studies have found that the human gut hosts five hundred species of microbes – and seven million microbial genes – that were unknown until now. The proportion of the gut flora that had been hidden until now may hold essential information on the origin of a range of diseases (IBD and metabolic syndrome, among others), as well as the clues on how to cure them.

The two studies were published in Nature Biotechnology in July, and come from the efforts of the MetaHIT (METAgenomics of the Human Intestinal Tract) project, a European consortium working to explore the composition of human gut microbiota.

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White bread discovered to be a good ally of our gut microbiota

Baguette and sliced bread lovers, we’ve got good news for you! For years,  it’s been criticized for its bad nutritional reputation and has been shunned as a mere glutinous slab lacking any health benefits, but white bread may help boost some of the beneficial gut microbes, according to a new paper recently published in the Journal of Agricultural and Food Chemistry.

It’s been known for decades that the close relationship between health and gut microbiota and that a healthy diet is essential for maintaining a balanced and rich population of gut bacteria. Up until now, a large number of studies had focused, precisely, on the effects of the food we eat on our gut flora, especially dietary fibre. In contrast, there was little to no information on other highly correlated diet components, such as polyphenols. A team of researchers from the University of Oviedo and the Spanish Research Council (CSIC) wanted to close that gap and set out to explore the association between gut microbiota composition and the intake of both fibres and polyphenols (common in much of what we consume like fruit, tea, spices, chocolate or wine) in a regular diet. Read more

Gender, education, and breastfeeding determine ones microbe mix

The mixture of microbes that live in a person’s body (and play a key-role for that person’s health) depend on a few, crucial facts of his or her life history. Gender, education, and whether the person was breastfed or not, shape the bacterial populations of the organism.

For example, a person with higher education has a different mix of microbes in his/her gut (the gut flora or gut microbiota) than that of a less educated one. Or one that has been breastfed has a bacterial population in the mouth and the gut that are not the same as those of a bottle-fed person.

Those key life events were identified in a study published recently in Nature by Tao Ding and Patrick Schloss, of the University of Michigan. Drawing data from the Human Microbiome Project and complementing it with additional measurements, the authors monitored the bacteria in eighteen body sites (mouth, nose, gut, ears, etc.) of 300 healthy individuals for almost two years. They focused on four bacterial communities, used genomic analysis to identify their presence, and measured the proportion of each one of them in each body sites. In that way, they could find the varying abundance of these four populations in the monitored individuals. Read more

Exposure to microbes in household dust during first year of life may reduce risk of asthma

Children who were exposed to certain bacteria of household dust during their first year of life have fewer asthma symptoms when they reach the age of three, according to a study published in the Journal of Allergy and Clinical Immunology.

It isn’t quite clear why household dust may be beneficial, but these new findings add to previous evidence that supports the hygiene hypothesis”. This theory argues that raising kids in a too clean environment results in less exposure to bacteria. As a consequence, their immune systems do not get the necessary training to learn when to react or not, which might explain the increase in allergies and asthma kids in modern countries have suffered in the past few decades.

Many allergens and microbes contained in dust come from animals and insects such as cats, cockroaches, dogs, dust mites and mice. Before the latest study, scientists already knew that exposure to such substances could be harmful for people who already suffer from asthma. Scientists also knew that exposure to several of those allergens in the first three years of life resulted in more wheezing and allergic reactions so they expected that exposure to these substances would also be associated with the development of asthma. Read more