This study involves the study of humans and mice, and studies a food additive called propionate, which can prevent the growth of mold and is widely used as a preservative in cheese, baked goods (including bread) and artificial condiments.
Studies have found that in mice, eating propionate can lead to short-term increase of blood sugar level, long-term weight gain and insulin resistance. (Insulin resistance refers to the body's poor response to insulin hormone, which helps cells absorb sugar or glucose. This resistance will lead to an increase in blood sugar levels in diabetic patients. )
In a small experiment involving humans, people who ate propionic acid temporarily increased insulin resistance within a few hours compared with those who did not eat additives.
However, this early study cannot prove that propionic acid can cause diabetes. In order to better understand whether propionate can cause diabetes in people, it is necessary to conduct a larger-scale study in a longer period of time. The US Food and Drug Administration allows nine disgusting things to be added to food.
In a paper published today (April 24th) in the journal Science Translational Medicine, the author wrote that these findings are still related to the range of use of propionate. They called for more research on the potential metabolic effects of food ingredients such as propionate.
"Understanding how food ingredients affect human metabolism at the molecular and cellular levels can help us formulate simple and effective measures to deal with the dual epidemics of obesity and diabetes," said Dr. Hotami Slijil, a senior author of the study and professor of genetics and metabolism at the Chen School of Health, Harvard University, in a statement.
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It is called "recognized as safe" by the US Food and Drug Administration (FDA), which means that this ingredient can be added to food without FDA approval. It is also a natural fatty acid, which is produced when intestinal bacteria break down fibers. However, no one has studied the metabolism of propionate as a food additive. The author said that in the new study, the researchers first gave propionate to mice and found that the additive led to the increase of several hormone levels. These include glucagon (telling the liver to release sugar into the blood), norepinephrine (involved in blood pressure regulation and raising blood sugar), fatty acid binding protein 4 or FABP4 (thought to be involved in fatty acid metabolism).
The surge of hormones leads to hyperglycemia, or hyperglycemia level, in mice.
When the researchers injected mice with low-dose propionic acid water (similar to the concentration found in preserved food) for 20 weeks, the animals gained weight and enhanced insulin resistance. Compared with mice that did not eat propionate, the researchers studied 14 healthy weight loss participants without diabetes. They went in.
In the crowd
Through testing, we can understand how these findings are transformed into humans. Participants were given a meal containing 1 g propionate (usually found in processed foods) or placebo. The subjects collected blood samples once before meals and regularly for 4 hours after meals. A week later, the subjects returned to the laboratory, and the subjects who initially took propionic acid took placebo, and vice versa. (This study is "double-blind", which means that neither researchers nor participants know who takes propionate and who takes placebo. )
This study found that when people take propionate, their hormone levels will increase, and when they take placebo, their hormone levels will increase.