2023-05-31 08:19:27
A UAB study in rats concludes that it causes a reduction in inflammation levels and less neuronal loss in the hippocampus.
“May your food be your only medicine” is a famous phrase attributed to Hippocrates (Greek doctor born on the island of Cos, Greece, in 460 BC and considered the greatest of all time). The best demonstration of the role of diet in health occurs in the population of the Okinawa archipelago (some 161 coral islands located south of Japan), which enjoys the highest life expectancy on the planet (it has 34 centenarians for every 100,000 inhabitants and, furthermore, all reach that advanced age in good health). This phenomenon is especially associated with a healthy diet, based on fish and fruit and vegetables, and hypocaloric (with a good balance between calories and physical exercise).
The world medical literature is full of references to the benefits of caloric restriction in adults, both in animal models (yeasts and nematodes, flies and mice) and in humans. Specifically, it is fully accepted that caloric restriction diets extend life expectancy and improve cognitive status, although many of the cellular processes involved are still unknown.
The latest evidence in this regard is provided by a study by the Autonomous University of Barcelona (UAB) conducted on Wistar rats, one of the most widely used models for laboratory research and a highly intelligent animal, with a brain that is similar to that of humans. . This work, published in Nutrientshas concluded that a hypocaloric diet attenuates brain changes related to memory loss associated with age.
Marta Portero, professor and researcher at the Institute of Neurosciences of the UAB (INc-UAB) and first author of the study, explained that some of the brain alterations observed during aging (increased oxidative stress and neuroinflammation, alterations in gene expression , reduced neurogenesis and deregulation of the mechanisms involved in synaptic plasticity) are related to the cognitive dysfunction that manifests naturally with age. These processes, which depend on both genetic and environmental factors, are especially important in the hippocampus.
For this reason, this work has specifically studied the effects of a caloric restriction diet on the hippocampus, which is a critical brain structure in learning processes, memories, recent memory, and orientation. And the results have corroborated that there is indeed a cognitive improvement derived from the hypocaloric diet and that it is linked to a reduction in inflammation levels and less neuronal loss in the hippocampus.
three groups of rats
In the study, coordinated by Gemma Guillazo, from the INc-UAB and the Department of Psychobiology and Health Sciences Methodology, and Carlos Barcia, from the INc-UAB and the Department of Biochemistry and Molecular Biology, the effects of of the diet in the hippocampus and in the memory and learning capacity of three groups of rats: one with four-month-old animals, which is equivalent to 30 years in humans, and two with advanced age (old) subjected to a restriction diet caloric (20-25% less food available) or with the ability to eat as much as they want.
As reported by Portero, it must be taken into account that the hypocaloric diet is not so much eating little as not eating excessive calories that are not needed or not spent, because eating for an active life is not the same as for a sedentary one. And age also influences: in childhood and youth many more calories are consumed than in adulthood and old age.
The results show that the group that has followed a hypocaloric diet presents better results in the test of spatial recognition of objects, a memory test that allows evaluating, among other things, the functioning of the hippocampus. In addition, the data obtained suggest that this improvement is linked to a reduction in both age-related neuronal loss and inflammatory activity in this structure; “The hypocaloric diet would be attenuating the inflammatory processes”, emphasizes Portero.
The importance of studying the factors related to healthy aging is shown by the fact that, although it is true that the life expectancy of the population has increased, it is also true that the incidence of neurodegenerative diseases associated with age has increased in parallel.
Reflection on lifestyles
When asked if the results of this study in rats could be extrapolated to those of a similar one carried out in humans, he answers that “it has a limited generalization in humans (…). What the study does is invite reflection on the importance of lifestyles in health, including brain health. Society has to be aware that a hypercaloric and trans fat diet has harmful effects on health and survival”.
Regarding the effects that a hypocaloric diet could have on older people with signs of neurological disease, Alzheimer’s type, the researcher confirms that “the diet is very clear regarding the benefits in prevention” and that, regarding its use as a supplement to therapies in people already diagnosed, “there are beginning to be studies on the possible benefits of a diet with antioxidants, physical exercise, sleeping well, having social contact, doing things and not having too much stress, which are factors that could be helping the disease progression slower.
Their study highlights the potential for behavioral changes, such as dietary modifications, to promote healthy brain aging and prevent age-related cognitive deficits. The work, however, continues in two ways: on the one hand, evaluating the effects of caloric restriction at different moments of life; and on the other, testing the use of a caloric restriction mimetic drug in mice, to see if it offers the same results as a hypocaloric diet. If so, it could be useful in prevention in humans.
Many studies in the world medical literature
Data from another 2020 study published in Cell, and headed by Juan Carlos Izpisúa, from the Salk Institute, in La Jolla, have already been conclusive: skimping on the calories that are ingested daily improves the immune system, reduces inflammation throughout the body, delays diseases that appear with age and, in general, favors a longer and healthier life. “Our results identify a large number of characteristics associated with age and that are avoided with caloric restriction at the molecular, cellular, tissue and organismal levels. These include cellular senescence, stem cell depletion, chronic inflammation, and aberrant communication between cells,” Izpisúa explained to this newspaper at the time.
In 2021, another study called Calerie-2carried out in the United States, published in The Lancet Diabetes and Endocrinology and consisting of healthy non-obese people maintaining 25% caloric restriction for two years, offered results that partially mimic what was already known from preclinical models, including weight reduction, improved insulin sensitivity, decreased stress oxidative and reduction of cardiovascular disease risk factors.
And years before, in 2017, it was published in Nature Communications another work with data collected in two previous studies that added a total sample of 200 monkeys followed over several years and that allowed us to confirm that caloric restriction does have a positive impact on both the health and survival of non-human primates . But the animals in the two studies were fed a low-calorie diet at different ages, and from the comparative analysis it emerged that eating less is beneficial in adult and older primates, but not in younger animals, an important finding regarding studies in rodents, in which the benefits of a restrictive diet had been seen to be superior, in other studies, the sooner one begins. Carmen Fernandez
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