For years, numerous animal studies have demonstrated how calorie-restricted diets could positively affect health and increase lifespans. On the other hand, human trials have been testing various dietary regimes that have established how calorie restrictions effectively lead to weight loss. However, up until now, it hasn't been clear for scientists whether long-term calorie-restricted diets would generate the same positive health benefits in humans as seen in animal studies.

How Proteins Play a Vital Role in Age-Related Immune Dysfunction Possibly Leading to Extended Human Lifespan

Calore-restricted diet
(Photo: Nathan Cowley from Pexels)

The recent Yale University-led research offers a robust investigation into the human health effects of long-term calorie-restricted diets ever conducted. Results of the study honed in on a specific protein that plays a vital role in age-related immune dysfunction and could lead to a targeted extension of human lifespans.

Researchers utilized data from clinical trials conducted a few years ago known as CALERIE or Comprehensive Assessment of Long term Effects of Reducing Intake of Energy. Researchers recruited roughly 200 healthy non-obese participants in the trial, where half of the group was tasked to reduce caloric intake by 25%.

The landmark trial lasted for two years, which allowed researchers a unique view into the long-term effects of calorie restrictions across a broad number of physiological biomarkers. By the end of the study, the interventional cohort achieved a consistent calorie reduction of 14$ from the baseline intake of participants at the beginning of the study.

Vishwa Deep Dixit, the senior author on the new Yale-led study, explains that the investigation into CALERIE data primarily focused on how long-term calorie restriction in humans influenced inflammation and immune response.

Dixit explains that since we are aware that chronic low-grade inflammation is a major trigger of numerous chronic diseases, it has adverse effects on a person's life span. He adds that in the recent study, the team asks what calorie restriction is doing to a person's immune and metabolic systems. If it is truly beneficial, how can we harness the endogenous pathways that mirror its effects in humans, reports NewAtlas.

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Analyzing Long-Term Calorie-Restricted Diets Effects on the Human Body

The study published in the journal Science, titled "Caloric restriction in humans reveals immunometabolic regulators of healthspan" upon analysis of MRI data focusing on the thymus gland. Researchers say that the thymus produces immune T-cells and is known to age more rapidly than any other organ in the human body. Age-related dysfunction of the organ is one of the reasons behind weak immune responses in the elderly.

Researchers also found that two years of calorie restrictions increase the thymus gland's functional volume compared to data gathered at the start of the trial. Meanwhile, a reduction in the fat of the thymus glands was also observed, compared to little changes in the control group that had no dietary restrictions. Dixit explains that the data indicates that the human thymus produced more T-cells after two years of calorie restriction.

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