New nutritional influences have been discovered
Diet has a significant impact on our mental and physical health. However, the impact could be greater than previously thought. German scientists were the first to prove in one study that nutrition has far-reaching functions than mere intake of nutrients. According to current research, food intake also affects hormone release and internal clock.
Researchers from the Helmholtz Zentrum Munich and the German Diabetes Research Center (DZD) have discovered hitherto unknown nutritional functions. They showed that the type of food or recorded episode of fasting had an effect on both hormone levels and changes in rest and activity within a 24-hour cycle. The results were presented by scientists in the respected Cell magazine.
What is an internal clock?
Every single cell in the human body is tuned to a so-called circadian rhythm – a kind of internal clock that is timed to a 24-hour daily routine that follows the natural course of day and night. Circadian rhythm is influenced by sunlight and social habits. According to the research team, a healthy person produces stress hormones every morning. These glucocorticoids cause the body to use fatty acids and sugars as energy sources to start the day with energy.
Circadian rhythm disorders, for example, as a result of illness, a night shift, or a jet, there are changes in the glucocorticoid. Such a disorder can cause serious metabolic disorders and, for example, promote diseases such as obesity, fatty liver, hypertension or type 2 diabetes.
What are glucocorticoids?
Glucocorticoids are a group of steroid hormones. For example, the stress hormone cortisol also belongs to this group. Glucocorticoids are important hormones that trigger metabolic processes in the body, thus regulating energy balance and providing energy sources. But they also have anti-inflammatory and immunosuppressive properties that affect the activity of the immune system.
The course of the study
To better understand the importance of daily release of stress hormones, the research team investigated the daily dependence of the metabolic cycle in mice. They examined the impact of diet. Using the latest technology, researchers analyzed the liver of mice every four hours. They were able to show when and where glucocorticoid receptors displayed their metabolic effects. The team analyzed the 24-hour cycle of liver metabolism and associated fluctuations in glucocorticoid release. Mice were fed the usual high-fat diet or diets or passed through short fasts.
What was observed?
Among other things, glucocorticoid release has been shown to be differentially regulated during fasting and during meals. Control is done by time-dependent binding of the hormone to the genome. This is evidence, according to the researchers, that most rhythmic gene activities are controlled by these hormones. This is also an explanation of how the liver differentially controls blood sugar and fat content throughout the day and night. In mice with impaired circadian rhythm, blood sugar and fat levels also changed.
Diet changes hormone response
In further tests, the researchers investigated how the mice responded to the injected drug dexamethasone (a synthetic glucocorticoid). Mice that are overweight in the high-fat diet have been found to respond differently to lean mice. "This is the first time we have been able to show that nutrition can alter hormonal and healing metabolic responses," explains Dr. Med. Fabiana Quagliarini from the research team. Because dexamethasone is often used in immunotherapy, consideration should be given to whether overweight people need different therapy from lean people.
Chronomemedicine is gaining in importance
"By understanding how glucocorticoids control 24-hour cycles of gene activity in the liver, and therefore blood sugar and fat levels, we gain new insights into chronic medicine and the development of metabolic diseases," adds Professor Henriette Uhlenhaut. The research group was the first to demonstrate at a molecular level a new relationship between lifestyle, hormones and physiology. This suggests that obese and normal-weight individuals may respond differently to the daily release of the hormone or glucocorticoid preparation. (Vb)
Graduate Editor (FH) Volker Blasek
- Helmholtz Zentrum Munich: Diet Can Affect Internal Clock and Hormonal Reactions (Accessed: 07/11/2019), Helmholtz-muenchen.de
- Fabiana Quagliarini, Ashfaq Ali Mir, Kinga Balazs, et al: Cystromic reprogramming of daily glucocorticoid hormonal response via high fat diets, Molecular Cell, 2019, cell.com