Myth: I’m going to have this disease because it’s in my genetics
There are several areas in life that influence your health. From what you eat, the movement you make, the relationships you have, the thought with which you face life, etc. A misconception that many still have is the role of genetics in certain diseases. This almost definitive association that a certain offspring causes a certain disease is mainly erroneous when it comes to chronic diseases. Too often, I hear people say that they have or are likely to have certain chronic illnesses because it runs in the family’s veins.
Chronic Illnesses and the Role in World Health
Chronic illnesses (also called non-communicable illnesses) last more than a year and usually require continuous medical attention and can somehow limit certain activities in a person’s life. The main diseases according to WHO are:
- cardiovascular (Cerebral Vascular Accident — CVA, arterial hypertension, etc.)
- Chronic respiratory diseases (asthma, chronic obstructive pulmonary disease)
- type 2 diabetes
- some types of cancer
- obesity
In the previous post, I also show some numbers regarding the impact of chronic diseases in the world.
According to WHO, 71% of the world population (41 million) die annually from some chronic diseases, of which 15 million are between 30 and 69 years old.
This study found that people with the 4 risk factors, 1. BMI >25; 2. Smoking; 3. Inactivity/sedentary lifestyle and 4. Alcohol consumption, compared to people with none of these risks, would live an average of 10 more years of healthy lives (without any chronic illnesses).
Risk factors
Genetic
By the time a baby is born, it has 25,000 genes from its parents and between 2 and 20 million genes from microorganisms such as bacteria. This means that we are 1% “equal” to our parents and the rest are microorganisms.
This first risk factor, which led me to write this publication, must be addressed in two “types” of genes that we have in us.
We are:
- 1% of genes received by our parents: these genes cannot be changed, it is something we receive at birth. But, a critical point is that of these 25,000 genes, not all of them are active, some of them are silenced. There are studies that indicate that it may be 33% active, others indicate 50% active and the rest inactive. It is, however, consensual that it is possible to influence the activation or silencing of genes through our habits and the surrounding environment. The study of this area is called epigenetics.
Epigenetics has been defined as ‘the study of mitotically (and potentially meiotically) heritable alterations in gene expression that are not caused by changes in DNA sequence’ Waterland, 2006.
- 99% of the microorganism genes (microbiome) that enter your body through the environment where you pass and what you eat. And then what you eat will also influence the type of microorganisms you feed.
Genetics and influence on chronic diseases
This study analysed the influence of genetics (G), exposure to factors during life (E) and the interaction between the two GxE in the onset of chronic diseases in true twins. The authors concluded that genetics is not the main factor influencing disease manifestation. Assuming that this group analysed in the study is representative of the European population, only about 16.4% of deaths from heart disease can be attributable to genetics.
For example, for cancer, exposure to harmful environments and/or lifestyle accounts for 90% of the risk and only 16.4% of deaths from heart disease can be attributable to genetics.
Results indicated that E-related typically explained more than 90% of cancer risk, consistent with the small genetic FAPs observed for cancers in MZ twins (median = 8.26%). Assuming that the populations of MZ (monozygotic) twins that were used to derive PAFs (population attributable fractions) are reasonable surrogates for Western Europeans in the year 2000, then 0.25 million of the 1.53 million cancer and heart-disease deaths (16.4%) can be attributed to G-related factors. Rappaport, 2016
The American Cancer Association states that, for example, for breast cancer, only 5–10% of cases are directly associated with genetics.
About 5% to 10% of breast cancer cases are thought to be hereditary, meaning that they result directly from gene changes (mutations) passed on from a parent. American Cancer Society
Some non-modifiable risk factors for Alzheimer’s are age and genetics. The studies below concluded that genetics play a more important role (about 50%) when it is the type of Alzheimer’s that appears before age 65 (first study mentioned below). However, these types of patients represent only 1% of the total with Alzheimer’s (second study mentioned below).
∼50% of early-onset sporadic Alzheimer’s disease cases or families with a mix of early/late-onset cases are genetically unexplained. Zhang et al., 2019
However, less than 1 percent of patients have autosomal dominant inherited Alzheimer’s disease (DIAD) which has a much earlier age of onset, around 45 years old. Liu, et al., 20018
There are several studies that assign percentage importance to different genetics. However, it is generally agreed that the genes of each one are only one factor that influence chronic diseases, and it is also agreed that it is not the most important factor.
Environmental
The environment we are exposed to is also a risk factor.
The wide range of environmental causes of cancer, encompassing environmental contaminants or pollutants, occupationally-related exposures and radiation, together make a significant contribution to cancer burden (65) and are often modified at low cost. Global status report on noncommunicable diseases 2010, WHO
Behavioural and Metabolic
Some modifiable behavioural factors I talked about in the post Myth: It is necessary to spend a lot of money to have a healthy diet, some of them being the consumption of tobacco, alcohol, poor diet, sedentary lifestyle, etc.
Here you can read more about the risk factors that WHO mentions as modifiable (tobacco, diet, alcohol consumption and sedentary lifestyle) and metabolic (hypertension, obesity, hyperglycaemia — excess blood glucose and hyperglycaemia — excess blood fat). These seconds, which are also indirectly linked to modifiable factors.
Final thoughts
There are several risk factors for the onset of chronic diseases, which can be divided into genetic, environmental and behavioural.
It is true that the behavioural factors are completely dependent on us, the environmental ones are also mostly controllable by us, although we may be subject to some type of work environment, we can and must work to have a healthy environment in our workplace.
The first factor I mention in this post, which may seem to be completely out of our control, our genetics in fact, can also be influenced by our habits. We can “turn off” and “on” the genes we receive from our parents, which represent about 1% of the total, depending on our eating habits, movement and the surrounding environment. The remaining 99% of our genes, our “friends” or “enemies” microorganisms, are also partly chosen by us. This is because we can feed our friends and let our enemies die or vice versa.
Regardless of how much we can influence the expression of our genes, how fast or slow we can improve our microbiome, or how effectively the percentage of our genes that overtly cause disease is something we should pay attention to because it is what is controllable within that which is partially uncontrollable.
We cannot control our genes, but we can influence whether they are turned on. We have the option of choosing foods that foods microbes good or bad.
Likewise, we have the opportunity, at least partially, to choose the surrounding environment. We must choose the behaviours that most distance us from risk factors for chronic diseases.
Even if the controllable is small, which is not according to the various studies above, it is what is in our hands, so that is what we should focus on. Focusing on our “bad” genes is like moaning about the rainy weather, it’s not by doing that it’s suddenly going to be a sunny day.
We must focus on the controllable, within the uncontrollable.
MYTH: I’m going to have this disease because it’s in my genetics
TRUTH: my genes may increase the risk of me having a certain disease, but they won’t stop me from fighting for this scenario not to happen.
Coach Corner
Now your turn: think about the last good thing you did to counteract some genes or disease tendency you have in your family?
What’s the last thing you did for your health?
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