Mice were fed a diet low in isoleucine and lived 33% longer than usual
A new study on mice demonstrating a way to prolong health and life was conducted by University of Wisconsin researchers. USA. It showed that reducing the amount of just one amino acid increases life expectancy by 33% of its average value.
Moreover, such a high percentage of longevity was found specifically in males. Females lived with reduced amino acid intake only 7% longer than average life expectancy.
We are talking about isoleucine – one of the three nutritional components we use as a source of protein. Isoleucine is not produced by the body on its own; it can be obtained from eggs, milk, soy protein and meat.
But it turns out that there is a norm for its consumption, exceeding which can achieve the opposite result – deterioration of well-being.
A new study in mice shows that limited intake of isoleucine slows the effects of aging and even extends lifespan.
“The various components of our diet not only have value, but can also add extra calories. We looked at one ingredient that people may be eating too much of, — says one of the authors of the work – metabolism researcher Dudley Lamming.
Scientists divided a group of mice into three subgroups and developed special diets for each. The first, as a control, was fed food containing twenty common amino acids, the second – those where the amount of all amino acids was reduced by approximately 2/3, a third – one in which only isoleucine was reduced by 2/3.
At the start of the study, the mice were about six months old, which is equivalent to the age of a 30-year-old human. They could eat as much as they wanted, but only from the ration that was provided.
The results showed that dietary restriction of isoleucine increased the lifespan and health of the mice, reduced their weakness, and also promoted leanness and normalized blood sugar levels. The lifespan of male mice increased by 33 percent compared to those in which isoleucine was not limited, and in females — by 7 percent.
Mice with less isoleucine in their diet also performed better on 26 health indicators, including muscle strength, endurance, tail use and hair loss. Male mice in this group showed less age-related prostate enlargement.
Interestingly, mice fed a diet low in isoleucine also consumed significantly more calories than others. But instead of gaining weight, they actually burned more energy and maintained a leaner body weight, although their activity levels were no different.
Researchers believe that restricting isoleucine in people through diet or pharmaceuticals may lead to similar anti-aging effects.
– Despite popular belief, recent research shows that protein components of food also play a significant role in the accumulation of excess fat mass. Branched-chain amino acids (called BCAA: leucine, isoleucine and valine) are elevated in the blood of obese people with poor metabolism. Reducing the level of BCAA in the diet to the required optimum has a beneficial effect on metabolic health, improves glucose tolerance and moderately slows down the increase in body fat mass. Of course, these amino acids themselves (most of them are found in chicken, red meat, fish, that is, in animal food) do not turn into fat – they only change our metabolism in such a way that the cells switch on a mode of greater storage of energy sources and gain of fat mass. Branched amino acids, which animal proteins are especially rich in, contribute to increased production of the hormone IGF-1 by the liver. This seems to be good, since it helps to gain muscle mass, strengthen bones, and regenerative processes (this is especially important for older people!). However, excessively high levels of this hormone provoke insulin resistance and cancer risk. On the contrary, limiting BCAA in the diet increases the levels of another hormone from the liver – FGF21, which helps normalize metabolism and longevity. In a new study by scientists from the USA, performed on mice, the standard diet reduced (but did not eliminate!) the intake of one of the BCAA amino acids – isoleucine. For comparison, the study was performed on young and old animals of both sexes. The experimental mice had improved liver health and glucose metabolism, and they became leaner. In addition to health, animals began to live longer, especially males. It is hardly worth transferring these data unconditionally to people, because the quality of protein (amino acid composition), especially in the diet of older people, often leaves much to be desired, – A poorer food basket and the inability to chew food thoroughly have an impact. It would be best if we resort, as our ancestors did, to periodic rather than constant restriction of animal protein, for example, in the form of fasting days.