Somewhere in the near future in the restaurant there are a woman and a man - on the first date. After the nervous tension subsides, everything goes well. A man is 33 years old, he says, and for most of this time he is alone. And although he does not talk about it, it becomes obvious that he wants to settle down and start a family. The woman answers that she is 52 years old, she was married, divorced and had children in 20 years. He is stunned: she looks at his age or even younger. This is the dream of Julie Mattison from the National Institute on Aging (NIA) in the United States. She foresees a time when the chronological age will tick every year, but the biological age can be translated so that the difference in age ceases to matter, as now.
It sounds unusual, but our society has already achieved great success in achieving this goal, thanks to advances in medicine and the improvement of a healthy lifestyle. For example, in 2014, a medical study in the United States showed that 16% of people aged 50 to 64 years each day suffer from chronic diseases. Thirty years ago this percentage was 23%. In other words, along with an increase in life expectancy, the duration of a healthy life increases. Life is added to years, not years to life.
So, what do we need to do to further increase the duration and quality of our lives? Scientists around the world are pursuing various ideas, but Mattison and her colleagues believe that the answer is simple: diet. They believe that the key to a better age will be a reduction in the amount of food on our plates - the so-called calorie restriction. This diet does not just cut fatty foods in the diet from time to time; we are talking about a gradual and thorough reduction in the size of portions. Since the early 1930s, a 30 percent reduction in daily food intake has been associated with a prolonged, more active life of worms, flies, rats, mice and monkeys. In other words, in the animal kingdom, calorie reduction was the best way to prolong life. It is possible that people should take this note.
The idea that what a person eats determines his health, undoubtedly goes back deep into the past. But, as often happens in any scientific discipline, the first detailed observations of this connection came from ancient Greece. Hippocrates, one of the first doctors, said that diseases are natural, not supernatural, and that many diseases were associated with overeating; the thick Greeks, as a rule, died before thin, it was obvious and written on papyrus.
Having spread out from this epicenter of science, its ideas were adopted and adapted throughout the centuries. At the end of the 15th century, Alvis Cornaro, a frail aristocrat from a small village near the Italian Venice, decided to test one old wisdom on himself.
If the indulgence was harmful, will dietetic asceticism be useful? To find out, Cornaro at the age of 40 years ate only 350 grams of food per day, which would be approximately 1,000 calories. He ate bread, a panatelle or broth with eggs. From meat, he chose veal, goat, beef, partridges and poultry. I bought fish caught in local rivers.
Abstaining in quantity but not in variety, Cornaro said he achieved "perfect health" by the time he died 40 years later. It is believed that he died in 84 years - which is impressive for the 16th century, when people in the 50-60 years were considered old men. In 1591 his grandson published a work in three volumes entitled "Conversations about a sober life", in which the very aging and restrictions in the diet were revised.
Cornaro argued that, having received an additional surge of energy in the old age, older people who fully possess their mental abilities, will be able to transfer his teachings further. With his diet, beauty has become the lot of the elderly, not the young.
In search of longevity
Cornaro was an interesting person, but his conclusions can not be taken for a fact in any of the scientific disciplines. Even if he was honest and did not hurt for almost half a century, which is unlikely, it's just the words of one person.
However, since then, a fundamental study conducted on white rats in 1935 showed that a dietary restriction of 30-50% prolongs life expectancy, delaying the onset of age-related diseases. Of course, what works for rats may not work for people.
Long-term trials that follow people from an early age to death are rare. "I do not imagine that a study of the duration of human life could become a funded research program," says Mattison. "Even if we take people at the age of 40-50, it will take another 40-50 years for research." In addition, to ensure that extraneous factors - exercise, smoking, treatment, state of mind - did not affect the final results of the study, it is almost impossible for our social and culturally complex species.
That is why in the late 1980s, two independent long-term studies were initiated - one at the NIA, and the other at the University of Wisconsin - to study calorie restriction and aging in Rhesus monkeys. We not only share 93% of the DNA with these primates, we are aging the same way.
Gradually, after middle age (about 15 years in Rhesus monkeys), the back begins to ache, the skin and muscles begin to sag, and where they are still growing, they become not blackish-brown, but gray. Similarities penetrate deeper. In these primates, the manifestation of cancer, diabetes and cardiovascular diseases is gaining momentum with age. "These are excellent models for studying aging," says Rosalyn Anderson, a gerontologist at the University of Wisconsin.
And they are easy to control. They were fed specially made biscuits, so the 76 monkey diets at the University of Wisconsin and 121 at the NIA were adapted to their age, weight and natural appetite. All monkeys received the full set of nutrients and minerals they needed. Just half of the monkeys ate 30% less.
And they could not be called malnourished or hungry. Take Sherman, a 43-monkey from the NIA. Matthyson says that when he was placed on a diet with a calorie restriction in 1987, at the age of 16, Sherman showed no obvious signs of hunger, which are well characterized in his species.
Sherman is the oldest rhesus monkey from the known, almost 20 years older than the average representative of its species, grown in captivity. As young monkeys fell ill and died, he seemed to be impenetrable for old age. Even at the age of 30, when he was considered old, he looked and acted differently.
The same is true, to varying degrees, for the rest of his experimental group at NIA. "We have a lower incidence of diabetes and a lower incidence of cancer in the CR groups," says Mattison. In 2009, the University of Wisconsin published similar impressive results.
Their monkeys with a limited diet not only looked younger - they had more hair, less gray hair, more brown, less gray - their standard-eating colleagues, they were healthier and more internal, less sick. The percentage of adenocarcinoma of the intestine decreased by half. Risk of cardiovascular diseases - too. And although 11 monkeys from the group receiving full benefit received diabetes, and 5 - a preliminary diabetic state, the regulation of glucose in the blood looked healthier among all monkeys with a limited diet. They were not afraid of diabetes.
In total, only 13% of monkeys in a group with a limited diet died from age-related diseases in 20 years. In the group of monkeys ad libitum (who received a full diet), 37% died to this age, almost three times more. In 2014, the survey update showed that the percentage remained the same.
"We demonstrated that aging in primates can be manipulated," says Anderson. "This is partly silent, because it is obvious, but conceptually it is very important; this means that aging itself is a reasonable goal for clinical intervention and treatment. "
If aging could be postponed, all related diseases would also follow suit. "Treating a disease at a time does not really prolong the life of a person, because he will die from something else," Anderson says. "If you cured all kinds of cancer, you can not save a person from cardiovascular disease, dementia or diabetes-related disorders. But if you postpone old age, you decide everything at once. "
Reducing food intake has definitely affected the health of monkeys, but limiting people to calories in the real world is much more difficult. First, our access to cheap and high-calorie food has become much simpler. Meals can be ordered at home. Weight is typed in itself, even do nothing.
"Genetics is involved in this whole matter and some people find it more difficult to stay in shape than others," Anderson says. "We all know people who can eat a whole cake and nothing will happen." Others, however, make the extra pirozhenka take the trousers a size larger. "
Ideally, the quantity and types of food that we eat should be adapted to who we are-our genetic predisposition to weight gain, how we metabolize sugar, how we store fat and how we treat psychologically. At present, all this goes beyond scientific instructions, and, perhaps, it will always be so.
But predisposition to obesity can be used as a guide to life decisions, and not as inevitability. "Personally, I have a genetic history of obesity going through my family, and I'm practicing a flexible form of caloric restriction," says Susan Roberts, a nutritionist at Tufts University in Boston. Currently, there are many useful tools that allow you to control your own body mass index and independently practice calorie restriction.
Roberts not only faced the problems of obesity herself, she also knows the advantages of calorie restriction better than others. For more than 10 years, she has been a leading research associate at Calerie. 218 healthy men and women aged 21 to 50 years were divided into two groups for two years. In one group, people were allowed to eat whatever they wanted (ad libitum), in another group - 25% less. Medical checks were conducted every six months.
Unlike tests of rhesus monkeys, two-year trials in humans do not allow to determine whether the reduction in caloric intake reduces the onset of age-related diseases. There simply is not enough time for their development. But the Calerie tests were tested for the first biological signs of heart disease, cancer and diabetes.
Published in 2015, the results after two years of testing were very positive. In the blood of people with reduced calorie content, the ratio of "good" cholesterol to "bad" cholesterol increased, TNF molecules decreased by 25%, and the level of insulin resistance, a sure sign of diabetes, fell by almost 40% compared to people who ate as usual. In general, blood pressure also fell.
Admittedly, some benefits can be caused by weight loss. Earlier Calerie studies included obese people, as well as people with a body mass index (BMI) of 25 or less, and weight loss definitely had a positive effect on heavier participants. It became obvious that overweight or obesity is bad. Diseases and disorders, which were previously associated with the diseases of the elderly, are now associated with obesity.
Recent results have shown that significant health benefits can be obtained in an already healthy human body that does not have a deficit or excess weight. That is, a person with a BMI between 18.5 and 25.
Despite these results, additional confirmation of the results of the studies is needed before recommending people to refrain from taking excess calories. And, obviously, any diet should be approved with a doctor.
In the meantime, scientists will hope that their rhesus macaques can help us understand why caloric restriction leads to such consequences. With almost 30 years of life and mortality data, as well as blood and tissue samples of nearly 200 monkeys, scientists have a lot to do at NIA and the University of Wisconsin to look into the black box of calorie restriction and highlight how it slows down aging.
Should the metabolism be more effective with what it has if the body gets less food? Is there a common molecular switch that regulates aging, which turns on (or turns off) when the caloric intake decreases? Or is there still an unknown mechanism underlying our life and death? The importance of monkeys like Sherman surpasses the importance of their lives.
Answers to such questions will not appear immediately. "If I cloned myself 10 times and we all worked around the clock, I do not think we would have found the answers," Anderson says. "Biology is extremely complicated." It's a worthy occupation - to try to understand how caloric restriction works and other methods of treatment work. Aging can be treated directly, without the need to limit calories, and this is truly the sacred grail of biology.
Despite the lack of a clear explanation, limiting calories is one of the most promising ways to improve health and longevity. "There was nothing that would make us decide that caloric restriction does not work for people," says Roberts. Unlike drugs, it also has no side effects. "Our people did not starve, their mood was excellent, the sexual function too. We were looking for flaws, but did not find them, "says Roberts.
One of the expected problems was a slight decrease in bone density, which is often associated with a gradual loss of weight, says Roberts. But as a precautionary measure, volunteers received small calcium supplements throughout the process.
The article is based on materials .
Comments
Post a Comment