We are bombarded daily by media clips proclaiming results of the latest study on how to live healthfully. Unfortunately these headlines are often conflicting, causing confusion and frustration in anyone trying to make sense of it all. Many people just stop listening.
Wouldn’t it be so much easier if all this information could be boiled down to a conclusion that is simple and clear enough to embrace as a part of our own daily lives? Take heart, we actually do have data from large scientific studies that does this for us. Let’s look at some of this evidence.
Just how much control do our genes have on our long-term health?
A British study looked at the genomic profiles of over 339,000 British men and women and examined the incidence of cardiovascular disease and diabetes. Study subjects who had higher genetic risk of certain diseases did show slightly greater incidences of cardiovascular diseases (high blood pressure, coronary artery disease, atrial fibrillation, stroke) and diabetes. However, those with low to intermediate genetic risk showed no increase in the incidence of these diseases. On the contrary, poor lifestyle practices (smoking; high Body Mass Index (BMI); not exercising; low consumption of fruits, vegetables and whole grains; high consumption of processed and non-processed meat and sugar-sweetened beverages) increased the risk of disease regardless of the genetic risk. For instance, in diabetes, an ideal lifestyle seemed to negate genetic risk but a poor lifestyle was associated with a 15-fold higher risk in those already at high genetic risk for the disease. Researchers concluded that lifestyle had a much stronger effect on the development of disease than genetics, summarizing their results by saying that the genetic risk makes “little contribution to health outcomes for cardiovascular disease and diabetes. The fault does not appear to lie in our genes but our choices.” Adherence to ideal lifestyle factors can lower incidence of disease regardless of genetic risk. (1)
It has been calculated that only 5 to 10% of all cancer cases can be attributed to the genome; the root of the remaining 90 to 95% of cancers is to be found in lifestyle and environment. Negative lifestyle and environmental factors include smoking, poor diet (low consumption of whole grains, fruits and vegetables; high consumption of animal-based foods), lack of exercise, excessive alcohol use, high levels of unprotected exposure to sunlight, infections, stress and environmental pollutants (2).
Studies of identical twins indicate that more than 90% of cancer risk and 89% of cardiovascular disease can be explained by lifestyle and environmental factors alone (3). Other studies reveal that, through a combination of not smoking, maintaining a normal BMI, enjoying moderate physical activity and eating a healthy diet, 90% of type-2 diabetes, 80% of coronary artery disease, 70% of stroke and 70% of colon cancer are preventable (4).
On top of this, our genes can be altered through lifestyle influences. This is the basis of the fairly new science called epigenetics, which is the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself. Epigenetic gene changes are heritable and so are passed down into the next generations of the organism (5). Plant-based diets have been shown to have the ability to alter the activity of hundreds of different genes (6). Eating plants induces gene changes that upregulate disease-preventing genes and downregulate genes that promote inflammation and diseases such as cancer (7). So even if you have genes of a dubious nature, your diet can prevent them from expressing their threatening consequences.
You can see that lifestyle and environment play an enormous role in our health. Fortunately we have a great amount of control over both of these elements. This realization should come with a sense of relief. There may be nothing we can do to change the genes we are born with but we do have substantial power over elements of our life that can change our genetic blueprint. Indeed, there IS something we can do to promote good health throughout a long life.
The European Prospective Investigation into Cancer and Nutrition (EPIC-Norfolk) (8)
Results of a British study, part of the very large Europe-wide EPIC study, come to us from Norfolk in the United Kingdom. Norfolk is a county that encompasses a wide range of socioeconomic conditions and both urban and rural communities. In this study, just over 20,000 men and women living in Norfolk between the ages of 45 and 79, who began the study free of cancer and cardiovascular disease, were followed for an average of eleven years to see how four simple behaviours affected their risk of dying. These four lifestyle actions were smoking, physical activity, alcohol intake, and fruit and vegetable consumption.
Each subject was given a health behavior score of 0 to 4.
- One point was given for not smoking.
- One point was given for being physically active (Physical inactivity was defined as having a sedentary job and performing no exercise)
- One point was given for moderate alcohol intake, defined as 1 to 14 units of alcohol per week with 1 unit being a half pint of beer, a glass of wine or a shot of spirit.
- One point was given for having a blood Vitamin C level consistent with fruit and vegetable intake of at least five servings a day.
Special Note: This is an interesting way to quantitate level of fruit and vegetable intake. Primates, of which human beings are a part, lost the ability to produce Vitamin C during their evolution and yet Vitamin C is an important vitamin necessary for health. Our ancestors thrived on a diet consisting overwhelmingly of fruits and vegetables. It appears that, because primate species consumed much more Vitamin C than necessary, the loss of the ability to synthesize this vitamin would put them at no evolutionary disadvantage. Of course, modern life has changed the human situation. Today, each individual has a wide range of foods to choose from and does not necessarily eat enough fruits and vegetables to obtain sufficient Vitamin C.
After allowing for factors such as age that would also affect the occurrence of death, those participants with a health behavior score of 0 were 4 times more likely to have died during the course of this study than those with a score of 4. Additionally, those with a score of 2 were twice as likely to have died.
The combination of four simple lifestyle choices predicts a 4-fold difference in the risk of dying over an average period of eleven years for people between 45 and 79.
A person with a health score of 0 was calculated to have the same risk of dying as a person fourteen years older who had a health score of 4.
The European Prospective Investigation into Cancer and Nutrition (EPIC-Potsdam) (9)
A similar study was performed in Potsdam, Germany where over 23,000 German participants aged 35 to 65 years were followed for an average of 7.8 years for incidence of type-2 diabetes, myocardial infarction, stroke and cancer. Once again, four healthy factors were scored;
- Never smoking
- BMI lower than 30
- At least 3.5 hours per week of physical activity
- Adhering to healthy diet principles (high intake of fruits, vegetables, and whole-grain bread and low meat consumption)
After adjusting for age, sex, educational status and occupational status, results showed the risk for developing any chronic disease decreased as the number of healthy factors increased.
Participants following all four healthy factors had a 78% lower risk of developing a chronic disease with specifically a 93% lower risk of diabetes, an 81% lower risk of myocardial infarction, a 50% lower risk of stroke and a 36% lower risk of cancer compared to participants with no healthy factors.
Following four simple healthy lifestyle factors has a strong influence on prevention of chronic diseases
The National Health and Nutrition Examination Survey (NHANES) in the United States (10)
A US study looked at the links between three healthy lifestyle behaviours and death. Over 8000 participants over the age of 20 were followed for an average of 5.7 years.
The three behaviours being examined were;
- Smoking – Being a non-smoker (not smoking more than 100 cigarettes during life
– Being a smoker who had quit (had smoked more than 100 cigarettes but was not smoking at the time of the study
– Currently smoking (had smoked more than 100 cigarettes and was smoking at the time of the study
- Physical Activity over the past 30 days with the goal of 150 minutes or more of moderate to vigorous activity per week
- Being in the top 40% of the Healthy Eating Index , calculated by positive and negative scores relating to the consumption of grains, fruits, vegetables, dairy, meats, fats, saturated fat, cholesterol, sodium and food variety.
Risk of death from all causes was…
Decreased by 56% by not smoking
Decreased by 47% by being physically active
Decreased by 26% by eating a healthy diet.
Compared to participants with no healthy behaviours, the risk decreased progressively as the number of healthy behaviours increased;
40% decrease in risk of death for one healthy behavior
55% decrease in risk of death for two healthy behaviours
82% decrease in risk of death for three healthy behaviours.
Following all three healthy behaviours reduced early death…
…from cardiovascular disease by 65%
…from cancer by 83%
…from other causes by 90%.
Adults who follow the three healthy behaviours of not smoking, eating a healthy diet and engaging in physical activity, substantially reduce their risk for early death over the short to medium term.
The Global Burden of Disease Study (11)
Analysis of the Global Burden of Disease Study 2017 looked specifically at the impact of dietary factors on death due to non-communicable chronic diseases. Intake of fifteen foods and nutrients among adults aged 25 years and older across 195 countries were tabulated, their optimal level of intake determined (the level of risk exposure that minimizes the risk from all causes of death) and then examined for the impact of each food on death from non-communicable chronic diseases.
Global intake of nearly all healthy foods and nutrients was suboptimal in 2017.
In parallel, daily intake of all unhealthy foods and nutrients exceeded the optimal level globally.
More than half of diet-related deaths and two-thirds of increased years of disability were attributable to high intake of sodium, low intake of whole grains and low intake of fruits.
Other significant risk factors for mortality included low intake of nuts and seeds, low intake of vegetables and low intake of omega-3 fatty acids.
Improvement in diet could potentially prevent one in every five deaths globally.
Suboptimal diet is responsible for more deaths than any other risks globally, including tobacco smoking.
Dietary risks affect people regardless of age, sex and sociodemographic circumstances.
Summing it all up
Research worldwide has consolidated the evidence and come up with a simple health plan for everyone.
Here it is:
- Do not smoke.
- Exercise at least 150 minutes every week, or about 30 minutes on five days each week.
- Keep your BMI in the healthy range.
- Eat lots of fruits and vegetables, nuts, seeds and whole grains and avoid meat, saturated fat, refined sugar and sodium.
Our genes play only a small part in our ability to lead a healthy long life. The real driver behind our risk for chronic diseases is our lifestyle. Changing just a very few simple things can make a huge difference in our health, our life satisfaction and how long we are around on this earth to enjoy it.
As researchers from the EPIC-Norfolk study point out, a few simple steps can add fourteen HEALTHFUL years to your life.
1 Associations of Combined Genetic and Lifestyle Risks with Incident Cardiovascular Disease and Diabetes in the UK Biobank Study JAMA Cardiology DOI: 10.1001/jamacardio.2018.1717
2 Anand, P., Kunnumakara, A.B., Sundaram, C., Harikumar, K.B. et al. Cancer is a Preventable Disease that Requires Major Lifestyle Changes .Pharm Res. 2008 Sep; 25(9): 2097–2116.
3 Rappaport, S.M. Genetic Factors Are Not the Major Causes of Chronic Diseases. PLoS One. 2016; 11(4): e0154387.
4 Willett, W. C. Balancing Lifestyle and Genomics Research for Disease Prevention. Science. 2002;296:695–698.
5 Berger, S.L., Kouzarides, T., Shiekhattar, R., Shilatifard, A. An operational definition of epigenetics. Genes & Development. 23 (7): 781–783.
6 Bøhn, S.K., Myhrstad, M.C., Thoresen, M., Holden, M., Karlsen, A,, Tunheim. S,H, et al. Blood cell gene expression associated with cellular stress defense is modulated by antioxidant-rich food in a randomised controlled clinical trial of male smokers. BMC Med. 2010 Sep 16; 8:54.
7 Ornish, D. Mostly plants. Am. J. Cardiol. 2009;104(7):957–958.
8 Khaw, K.T., Wareham, N., Bingham, S., Welch, A., Luben, R., Day, N. Combined impact of health behaviours and mortality in men and women: The EPIC-Norfolk prospective population study. PLoS Med. 2008 5(1):e12.
9 Ford, E.S., Bergmann, M.M., Kröger, J., Schienkiewitz, A., Weikert, C., Boeing, H. Healthy living is the best revenge: Findings from the European Prospective Investigation Into Cancer and Nutrition-Potsdam study. Arch. Intern. Med. 2009 169(15):1355 – 1362.
10 Ford, E.S., Bergmann, M.M., Boeing, H., Li, C., Capewell, S. Healthy lifestyle behaviors and all-cause mortality among adults in the United States. Prev Med 2012 55(1):23 – 27.
11 Afshin, A., Sur, P.J., Fay, K.A., Cornaby, L., Ferrara, G., Salama, J.S., Mullany, E.C. et al.
Health effects of dietary risks in 195 countries, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017. Open AccessPublished: April 03, 2019 DOI:https://doi.org/10.1016/S0140-6736(19)30041-30048.