FOOD BITES

Compiled by Angela S. Hoover, Staff Writer

Food Affects Each Person’s Gut Bacteria Differently

The types of foods we eat affect the makeup of our gut microbiomes. Yet the same food can have different effects in different individuals. The specifics of how diet influences a person’s gut is still a mystery. “A lot of the response of the microbiome to foods is going to be personalized because each person has that unique mixture (of microbes) that’s special only to them,” said Dan Knights, a computational microbiologist at the University of Minnesota. Gut microbes have a major influence on health, from losing weight to heart disease and even the immune system. But the connection of the microbiome and health is poorly understood. In a very detailed “shotgun metagenomics” analysis – taking random samples of the genetic sequences in the microbes of fecal material to determine which species and what genes the sequences came from – the researchers could predict changes in the microbiome based on what a participant had eaten in the previous days. For each person, they found a median of nine specific relationships between a type of food and specific gut microbiome changes. The team found more than one research participant shared 109 total food-gut microbe relationships, but only eight were shared by more than two. In one participant, eating a particular vegetable caused a specific group of bacteria to multiply greatly, but in another participant, eating the same vegetable could eliminate that same bacteria group. “There are very clearly other sources of variation in the microbiome in addition to the foods we eat,” Knight said. The findings were published in the journal Cell Host & Microbe on June 12, 2019.

New Arsenic Compounds Discovered in Rice Fields

Researchers from the University of Bayreuth and scientists from Italy and China have for the first time systematically investigated under which conditions and to what extent sulphurcontaining arsenic compounds are formed in rice-growing soils. To date, these thioarsenates have not been taken into account in assessments of the health effects of rice consumption. Bayreuth environmental geochemist Britta Planer-Friedrich developed a new method to reliably detect thioarsenates in rice soils. Routinely used methods to monitor arsenic in rice fields have not been able to detect sulphur-containing arsenic compounds or distinguish them from oxygen-containing arsenic compounds. At least one organic sulphur-containing arsenic compound discovered in rice fields is already known to be carcinogenic. It is important to specifically detect organic sulphur-containing arsenic compounds and examine them for toxicity. The researchers presume these compounds have been confused with non-toxic organic oxygenated arsenic compounds due to the inadequate measurement procedures. Planer-Friedrich calls for legally defined limits to be set for all toxic arsenic compounds. Presently, there is only a legal limit for inorganic oxygenated arsenic compounds, which are still categorized as non-toxic. With this new measuring method, the researchers observed the formation of sulphur-containing arsenic compounds over long periods in rice fields in Italy and China. “Our further studies will show whether thioarsenates as a whole represent risk or an opportunity for the production of rice containing the lowest possible amounts of arsenic. Only then can further directives for water or soil management in rice fields and the targeted breeding of new rice varieties be developed,” PlanerFriedrich said. The results were published in the journal Nature Geoscience in February. (Source: Environmental News Network)

The specifics of how diet influences a person’s gut is still a mystery.