Researchers from the Okinawa Institute of Science and Technology Graduate University (OIST) and Kyoto University in Japan examined the effect of fasting on metabolism. Recent studies on aging demonstrated that caloric restriction and fasting prolong lifespan in animal models.
For the study, the researchers recruited four participants and asked them to fast for 58 hours. They used metabolomics, or the measurement of metabolites, to assess the participants’ blood samples at intervals during the fasting period.
During fasting, several distinct metabolic changes occur. Normally, the body uses carbohydrates as fuel when available. However, once carbohydrates are gone, the body looks for other sources of energy, such as amino acids. This process is called gluconeogenesis. Evidence of gluconeogenesis can be found by analyzing the levels of certain metabolites in the blood, such as carnitines, and butyrate.
In the study, the levels of these metabolites increased in the participants’ blood after fasting. Interestingly, the researchers observed other metabolic changes. For one, they saw a significant increase in products of the citric acid cycle. This cycle occurs in the mitochondria, and its function is to release stored energy. The increase seen in the metabolites associated with this process indicated that the mitochondria are overworking.
The researchers found that the levels of purine and pyrimidine also increased. These chemicals serve as an indicator of increased protein synthesis and gene expression. The increase in these chemicals suggested that fasting causes cells to change the type and quantity of proteins that they need to function.
When purine and pyrimidine are metabolized, they also increase the body’s production of antioxidants. In the study, researchers saw a rise in antioxidants ergothioneine and carnosine. The researchers explained that the rise in antioxidants might be the body’s response to fasting because starvation can cause high levels of oxidative stress. By producing antioxidants, it might prevent potential damage from free radicals. (Related: Fasting activates your body's 'survival' mode, boosting your immune system.)
They also observed that fasting increased the metabolites leucine, isoleucine, and ophthalmic acid. These metabolites tend to decline with age. The researchers noted that this might explain how fasting prolongs lifespan in rats. Overall, the researchers identified 44 metabolites that increased during fasting, some of which increased by 60 times. Of the 44 metabolites, 14 were already previously linked to fasting.
Other potential health benefits of fasting
Fasting gained popularity in recent years, but this practice dates back centuries. Many researchers have studied the different types of fasting and their potential benefits. Although this type of diet may not be for everyone, here are some scientifically proven health benefits of fasting:
- Regulates blood sugar – Intermittent fasting and alternate-day fasting could lower blood sugar and reduce insulin resistance, according to a study in the journal Translational Research. Note that they may affect men and women differently.
- Fights inflammation – Fasting could also reduce levels of inflammation and promote better health. A study in 50 healthy adults revealed that intermittent fasting for one month reduced levels of inflammatory markers. Another small study saw the same effect when people fasted for 12 hours a day for a month. Fasting was also found to be beneficial for people with inflammatory conditions, such as multiple sclerosis.
- Supports heart health – Several studies show that fasting may be good for the heart. It reduces blood pressure, triglycerides, and cholesterol levels. A study in the journal Obesity revealed alternate-day fasting decreased cholesterol and triglyceride levels among obese adults. Another study, which evaluated over 4,000 people, found a link between fasting and a lower risk of coronary artery disease and diabetes.
Fasting may affect people differently. If you're interested in other ways to a longer, healthier life without resorting to fasting, visit Longevity.news.
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