22.
Genetic Factors
Largely A Myth
Another common myth is that bad health is caused by bad genes. Therefore–other than having picked different parents–there’s nothing you can do about your health as you grow older.
You’ve probably all heard a person say something like, “My Dad died of a heart attack at 54, and Grandpa died of one when he was only 49.” Generally such explanations are offered with a look of deep resignation and regret.
The man speaking is doomed to an early death, and there’s nothing he can do but accept the inevitable. And perhaps console himself with generous servings of barbecued ribs and French fries.
Obviously, there is a connection between genetics and aging. It’s well known, for example, that the length of life of non-identical twins varies much more than that of identical twins who are genetically identical.
When there are similarities in a family, is it the results of genes or the environment or a combination of the two? To answer this perennial question, the MacArthur Research Network considered the role of genes in several aspects of aging:
Some genetic diseases do clearly shorten life. A few are caused by a single gene. For example, if a person has Huntington’s disease, his or her children have a 50% chance of inheriting the gene from that parent. A child who inherits the gene will get the disease, unless, of course, he dies of some other cause before the disease manifests itself.
For all but a small number of conditions like Huntington’s disease, however, the MacArthur studies show that a person’s environment and lifestyle have a powerful effect on the likelihood that he will actually develop a disease.
It’s true that a family history of heart disease, some cancers, high blood pressure, familial high cholesterol, rheumatoid arthritis, and certain other diseases may put a person at risk, but that doesn’t mean that he or she will necessarily develop the disease.
We now know that diet, exercise, and even medications may delay or completely eliminate the emergence of the disease. Genes play a key role in promoting disease, but they are certainly less than half the story.
You’ve probably all heard a person say something like, “My Dad died of a heart attack at 54, and Grandpa died of one when he was only 49.” Generally such explanations are offered with a look of deep resignation and regret.
The man speaking is doomed to an early death, and there’s nothing he can do but accept the inevitable. And perhaps console himself with generous servings of barbecued ribs and French fries.
Obviously, there is a connection between genetics and aging. It’s well known, for example, that the length of life of non-identical twins varies much more than that of identical twins who are genetically identical.
When there are similarities in a family, is it the results of genes or the environment or a combination of the two? To answer this perennial question, the MacArthur Research Network considered the role of genes in several aspects of aging:
Some genetic diseases do clearly shorten life. A few are caused by a single gene. For example, if a person has Huntington’s disease, his or her children have a 50% chance of inheriting the gene from that parent. A child who inherits the gene will get the disease, unless, of course, he dies of some other cause before the disease manifests itself.
For all but a small number of conditions like Huntington’s disease, however, the MacArthur studies show that a person’s environment and lifestyle have a powerful effect on the likelihood that he will actually develop a disease.
It’s true that a family history of heart disease, some cancers, high blood pressure, familial high cholesterol, rheumatoid arthritis, and certain other diseases may put a person at risk, but that doesn’t mean that he or she will necessarily develop the disease.
We now know that diet, exercise, and even medications may delay or completely eliminate the emergence of the disease. Genes play a key role in promoting disease, but they are certainly less than half the story.
Effect Of Genes On Mental And Physical Function
To separate the effects of genetics from those of environment, the MacArthur researchers studied some twins who are reared apart.
Such studies clearly indicated that with rare exceptions, only about 30% of physical aging can be blamed on the genes and as we grow older, genetics becomes less important, and environment becomes more important.
Authors Rowe and Kahn, in their research conclude that the likelihood of conditions, such as obesity and hypertension, are largely not inherited and thus these risks are due to environmental and life style factors. How we live and where we live has the most profound impact on age-related changes in the function of many organs throughout the body, including the heart, immune system. lungs, bones, brain, and kidneys.
Diseases run into a family mainly because the diet pattern and life pattern of family members are often similar.
Also modern studies show that at most 15 percent of cancers are due - and only in part - to inherited genetic defects. Eighty-five percent are not.
However, cancer does run in families: A landmark New England Journal of Medicine study showed that children adopted at birth by parents who died of cancer before the age of 50 had the cancer risk of their adoptive parents, not of their biological ones. What gets passed on from one generation to the next are cancer-causing habits and environmental exposures, not just cancer-causing genes.
Such studies clearly indicated that with rare exceptions, only about 30% of physical aging can be blamed on the genes and as we grow older, genetics becomes less important, and environment becomes more important.
Authors Rowe and Kahn, in their research conclude that the likelihood of conditions, such as obesity and hypertension, are largely not inherited and thus these risks are due to environmental and life style factors. How we live and where we live has the most profound impact on age-related changes in the function of many organs throughout the body, including the heart, immune system. lungs, bones, brain, and kidneys.
Diseases run into a family mainly because the diet pattern and life pattern of family members are often similar.
Also modern studies show that at most 15 percent of cancers are due - and only in part - to inherited genetic defects. Eighty-five percent are not.
However, cancer does run in families: A landmark New England Journal of Medicine study showed that children adopted at birth by parents who died of cancer before the age of 50 had the cancer risk of their adoptive parents, not of their biological ones. What gets passed on from one generation to the next are cancer-causing habits and environmental exposures, not just cancer-causing genes.
Racial Vulnerability To Diseases
Some races are prone to some particular diseases than the others. For example, Indians are more susceptible to develop type 2 diabetes than other nationalities. But this differentiation is only partly due to genes. Diet and lifestyle factors play a major role. Every race has its own dietary and cultural patterns which define its susceptibility to a particular disease.
The basis for this hypothesis is strengthened by results of studies showing that people who migrate from one country to another generally acquire the chronic disease rates of the new host country, suggesting that environmental [or lifestyle factors] rather than genetic factors are the key determinants of the international variation in chronic disease rates.
It was noted in the 1970s that people in many western countries had diets high in animal products, fat, and sugar, and high rates of cancers of the colorectum, breast, prostate, and lung; by contrast, individuals in developing countries usually had diets that were based on one or two starchy staple foods, with low intakes of animal products, fat, and sugar, and low rates of these cancers. So it was diet, rather than genes that led to variation in these cancer rates.
The basis for this hypothesis is strengthened by results of studies showing that people who migrate from one country to another generally acquire the chronic disease rates of the new host country, suggesting that environmental [or lifestyle factors] rather than genetic factors are the key determinants of the international variation in chronic disease rates.
It was noted in the 1970s that people in many western countries had diets high in animal products, fat, and sugar, and high rates of cancers of the colorectum, breast, prostate, and lung; by contrast, individuals in developing countries usually had diets that were based on one or two starchy staple foods, with low intakes of animal products, fat, and sugar, and low rates of these cancers. So it was diet, rather than genes that led to variation in these cancer rates.
trimsad vimsati varsani
paramayuh kalau nrnam
The maximum duration of life for human beings in Kali-yuga will become fifty years.
(Srimad Bhagavatam 12.2.11)