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Twin Studies - Not a Fan of Genetic Testing

Genes load the gun - your environment pulls the trigger!

From my book, "Health Freedom Lost," Volume 2 - Restoring Health Freedom.

Genetics and Epigenetics

Genes vary by 0.1 percent in humans, but how we live varies by 99.9%.

It is quite naïve to have only two classifications. Instead, we all lie on a health-disease continuum. Somewhere in the world is the healthiest person who is or will live close to 120 years of age. Somewhere else is a young person on death’s door. The rest of us lie somewhere in between. These two extremes set the upper and lower limits for the health continuum.

Humans are 99.9% the same genetically, according to the National Institutes for Health (NIH) Human Genome Research Institute.[i] Humans are also close cousins of other animals, with a genetic material overlap of 96 percent with chimpanzees, 90 percent with cats, and 85 percent with rats. Leave it to the Federal Government to make wrong conclusions as the NIH indicates that the 0.1 percent difference in genetic makeup holds important clues about the causes of disease. They have not studied identical twins' health profiles that share identical genes.

Indeed, there are some rare genetic diseases like Downs Syndrome and Sickle Cell Anemia, and they are sometimes detected at birth or before. The remaining ~70,000 diseases coded in ICD-10 are behavioral and environmental. The many twin studies corroborate this very clearly. However, authors of these studies often confuse genetics for epigenetics when concluding the reason for differences in twins' health. The article “Twins and Cancer: Nature, Nurture, or Something Else?” clarifies the factors impacting disease outcomes.[ii]

If genetics controlled your health rather than you controlling your genetics, then many of the tests performed to assess your health and interventions provided to you would be of no real value. This is because even advanced medicine cannot treat your genes but can treat you.

Epigenetics studies how behaviors and the living environment can cause changes that affect how genes work. Unlike genetic changes, epigenetic modifications are reversible and do not change the DNA sequence. However, they can change how the body reads a DNA sequence. This discussion about genes versus epigenetics versus lifestyle and environment is critical. If diseases are primarily tied up in our genes, why make any effort to be healthy? Our genes do NOT dominate diseases; instead, diseases are governed by our situations and behaviors.

Your decisions dictate your health.

Infection can alter the host genome. If the host for infection is one of two twins in the womb, these identical twins are destined to be different and possibly quite different. No research into twins and health take this into account. Time spent in the womb is considered identical in identical twins. However, this is not likely the case. Take your eyes as an example. Every individual has two eyes. An individual may experience exposure to something harmful, like a pathogen, that leads to an eye disease. Most often, eye disease first impacts just one eye. After that, it may spread to the "fellow" eye but seldom does the condition immediately manifest in both eyes simultaneously.

Paul Kellam and Robin Weiss explain the consequences of infection on the genome in their paper titled “Infectogenomics: insights from the host genome into infectious diseases.” Their conclusion is included here.

“The functional genomics of the host is crucial in analyzing host-pathogen interactions. Host genetic variation plays a key role in determining the outcome of many potentially pathogenic infections, and the prevalent pathogens have influenced the genetic makeup of human populations. Infectogenomics can be harnessed to identify infectious states, understand the host response, predict disease outcomes, monitor responses to antimicrobial therapies, and indicate promising new types of treatment.

In addition, we should acknowledge that the disease state can inform our understanding of normality. Just as virology led us to oncogenes, tumor suppressor proteins, membrane trafficking pathways, and other aspects of molecular cell biology in the past, so can studies of the perturbation of the transcriptome by infection open new vistas onto “systems” biology today.”

Infections historically are the major cause of disease and early death. However, in the modern era, conditions are not considered to be caused by infection. Instead, tens of thousands of human labels are applied to diseases, including cardiovascular disease, cancer, diabetes, and Alzheimer’s disease. Infections of all types illicit a reaction by our immune system that is measurable with biomarkers. In Volume 1, a chapter is devoted to understanding the stealthy but prolific nature of infections in modern diseases.

Measuring biomarkers may be unimportant if diseases were genetic because genes cannot be treated. Fortunately, almost all conditions are treatable and reversible. Thus, measuring biomarkers and applying treatment protocols based on biomarkers and risks remains the single most important way to ensure good health or reverse diseases. Interestingly, the change in biomarkers with stealth, chronic-phase infections is small. Thus, with the current reference ranges not based on science, individuals infected with chronically usually test “normal.” Therefore, the person with this condition has a smoldering disease that goes undetected until it suddenly erupts sometime in the future, to the “surprise” of the medical team.


For the visually impaired:

“You really learn very little about your own life span from your parents’ life spans,” Dr. Vaupel said. “That’s what the evidence shows. Even twins, identical twins, die at different times.” On average, he said, more than 10 years apart."


For twins raised together in similar settings who share the same genetic profiles, it isn’t surprising that one’s illness could befall the other, like identical twin girls diagnosed with a rare leukemia at three months old; or identical twin brothers who each received an ALS diagnosis within weeks of each other.

Identical twins in Finland who shared the same sports and other physical activities as youngsters but different exercise habits as adults soon developed quite different bodies and brains, according to a fascinating new study that highlights the extent to which exercise shapes our health, even in people who have identical genes and nurturing.

Determining the precise, long-term effects of exercise is surprisingly difficult. Most large-scale exercise studies rely on questionnaires or interviews and medical records to establish the role of exercise. But these epidemiological studies, while important and persuasive, cannot prove that exercise causes health changes, only that people who exercise tend to be healthier than those who do not.

Some past studies had found that older identical twins whose workout habits had diverged over the years tended to age differently, with greater risks of poor health and early death among the sedentary twin.

But no studies had looked at young twins and the impacts of different exercise routines on their health. So for the new study, which was published this month in Medicine & Science in Sports & Exercise, researchers at the University of Jyvaskyla and other institutions in Finland turned to that country's extensive FinnTwin16 database, which contained twins' answers to questionnaires about their health and medical conditions, beginning when the pairs were 16 and repeated every few years afterward.

The researchers were looking for young adult identical twins in their early- to mid-20s whose exercise habits had substantially diverged after they had left their childhood homes. These twins were not easy to find. Most of the pairs had maintained remarkably similar exercise routines, despite living apart.

But eventually the researchers homed in on 10 pairs of male identical twins, one of whom regularly exercised, while the other did not, usually because of work or family pressures, the researchers determined.

The dissimilarities in their exercise routines had mostly begun within the past three years, according to their questionnaires.

The scientists invited these twins into the lab and measured each young man's endurance capacity, body composition and insulin sensitivity, to determine their fitness and metabolic health. The scientists also scanned each twin's brain.

Then they compared the twins' results.

It turned out that these genetically identical twins looked surprisingly different beneath the skin and skull. The sedentary twins had lower endurance capacities, higher body fat percentages, and signs of insulin resistance, signaling the onset of metabolic problems. (Interestingly, the twins tended to have very similar diets, whatever their workout routines, so food choices were unlikely to have contributed to health differences.)

The twins' brains also were unalike. The active twins had significantly more grey matter than the sedentary twins, especially in areas of the brain involved in motor control and coordination.

Presumably, all of these differences in the young men's bodies and brains had developed during their few, brief years of divergent workouts, underscoring how rapidly and robustly exercising — or not — can affect health, said Dr. Urho Kujala, a professor of sports and exercise medicine at the University of Jyvaskyla who oversaw the study.

More subtly, the findings also point out that genetics and environment "do not have to be" destiny when it comes to exercise habits, Dr. Kujala said. For these particular twins, whether their genes and childhoods nudged them toward exercising regularly or slumping on the couch, one of the pair overcame that legacy and did the opposite (for better and worse).


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