Proteins are one of the essential part of the a balanced diet, it’s needed for growth and maintenance of cells. All cells, body organs, cell membranes, muscle cells, hair, nails, skin, enzymes, hormones and everything in body has protein as a basic constituent. Though an essential part, high protein intake can be a great danger to health, so says a new study conducted by Valter Longo, Edna M. Jones Professor of Biogerontology at the USC Davis School of Gerontology and director of the USC Longevity Institute.
The researchers examined a large sample of adults for nearly two decades and found that the diet rich in proteins during middle age increases the chance of dying of cancer by four times compared to a person with a low protein diet. Thus making the mortality rate comparable to smoking.
Research proves that middle aged people who eat lots of proteins from animal sources including milk ,meat are not only susceptible to die from cancer, but are also more likely to die earlier. They are 74 % more likely to die of any cause within the study period than low protein consumers. Even people who ate moderate amount of proteins were still three times more likely to die of cancer than lower protein eater. It was seen that change from moderate to low levels of protein taken reduced the likelihood of early death by 21%.
Not only that but this study also draws other important conclusions. One is how biology changes as we age and how food consumed in middle age impacts a person’s life span. Before this, most studies considered adulthood rather than other age groups.
So how an increased protein consumption increases the risk of mortality? Protein controls the growth hormone IGF-1, increased levels of which is associated with cancer formation. The levels of IGF-1 start dropping dramatically after the age of 65, resulting in frailty and muscle loss. While high protein intake in middle age is associated with elevated risk of cancer (as there is no deficiency of IGF-I). In old age, it’s exactly opposite growth hormone levels decrease and more protein should be consumed to maintain the growth and repair of cells.
This evidence backs up the previous research that showed that mutation resulting in IGF-1 deficiency in subjects (all subjects were less than 5 feet tall) lowered the risk of cancer and diabetes.
The conclusion of the research is that low protein diet is useful in middle age, but in old age a high protein diet should be eaten because high levels of IGF-1 increases the mortality rate along with making a person vulnerable to cancer and diabetes (by disturbing insulin levels).
But an interesting thing scientists observed was that plant protein seemed to have no such effects like increasing mortality risk due to cancer and diabetes like animal proteins do. The rate of cancer mortality also was not effected by changing carbohydrates and fat levels, proving that animal protein is the only factor contributing to above mentioned harmful effects.
Everyone has cancerous or precancerous cell at some point of their lives, but its the factors which increase the risk of cancerous cell division and its metastasis, one of the major factor being the high protein consumption.
Scientists advice not to take more than the recommend levels of proteins and in middle age, maintaining a low level of protein is advisable but don’t cut it down to the extent that it leads to malnutrition and most preferably fulfill your body’s protein requirements by plant proteins.
[Source: University Of Southern California | Image Via Goodfon]