New nutritional influences discovered
Diet has a significant impact on our mental and physical health. However, the impact could be even greater than previously thought. German scientists were the first to prove in a study that diet has more far-reaching functions than mere intake of nutrients. According to the current research, dietary intake also affects our hormone release and internal clock.
Researchers from the Helmholtz Zentrum München and the German Center for Diabetes Research (DZD) discovered previously unknown functions of nutrition. They showed that the type of food or fasting episodes recorded affects both the hormone level and the change between rest and activity within the 24-hour cycle. The results were presented by the scientists in the renowned journal "Cell".
What is the internal clock?
Each individual cell in the human body is tuned to the so-called circadian rhythm – a kind of internal clock which is timed to the 24-hour daily routine and follows the natural course of day and night. The circadian rhythm is influenced by sunlight and social habits. According to the study team, a healthy person produces stress hormones every morning. These glucocorticoids cause the body to use fatty acids and sugars as sources of energy to start the day with energy.
Disorders of the circadian rhythm, for example, as a result of diseases, night shifts or jet lag, there are changes in the glucocorticoid. Such a disorder can cause severe metabolic dysregulations 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 the energy balance and providing energy sources. But they also have anti-inflammatory and immunosuppressive properties that affect the activity of the immune system.
Course of the study
To better understand the importance of the daily release of stress hormones, the research team investigated the daytime-dependent metabolic cycling in mice. They examined the influence of the diet. Using the latest technologies, the researchers analyzed the liver of the mice every four hours. They were able to show when and where glucocorticoid receptors exert their metabolic effects. The team analyzed the 24-hour cycle of liver metabolism and the associated fluctuations in glucocorticoid release. The mice were fed either normal or high-fat diets or passed through short periods of fasting.
What was observed?
Among other things, it was shown that the glucocorticoid release is regulated differently during fasting periods and when eating. The control takes place via a time-dependent binding of the hormones to the genome. This is evidence, according to the researchers, that the majority of the rhythmic gene activities are controlled by these hormones. This is also an explanation of how the liver controls the sugar and fat content in the blood differently during the day and night. In mice with disturbed circadian rhythm, there was also a change in the sugar and fat levels in the blood.
Diet changes the response to hormones
In further tests, the researchers investigated how the mice reacted to the injected drug dexamethasone (synthetic glucocorticoid). It was found that mice that were overweight due to high fat diet, reacted differently to the drug than lean mice. "This is the first time we have been able to show that nutrition can alter the hormonal and medicinal reactions of the metabolism," explains Dr. med. Fabiana Quagliarini from the research team. Since dexamethasone is often used in immunotherapy, consideration should be given to whether overweight people need different therapies than lean people.
Chronomemedicine is gaining importance
"Understanding how glucocorticoids control the 24-hour cycles of liver gene activity and thus 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 show a new relationship between lifestyle, hormones and physiology at the molecular level. This suggests that obese people and persons of normal weight could react differently to the daily hormone release or glucocorticoid preparations. (Vb)
Graduate editor (FH) Volker Blasek
- Helmholtz Zentrum München: Diet can affect the internal clock and hormonal reactions (Available on: 07.11.2019), helmholtz-muenchen.de
- Fabiana Quagliarini, Ashfaq Ali Mir, Kinga Balazs, et al .: Cistromic Reprogramming of the Diurnal Glucocorticoid Hormone Response by High-Fat Diet, Molecular Cell, 2019, cell.com
Diet (t) Internal clock (t) Circadian rhythm (t) Metabolism (t) Glucocorticoids (t) Cortisol (t) Hormones