Alcohol and cigarettes are both part of Group 1 carcinogens, which is the group of substances associated with the highest risk of causing cancer. According to molecular biologist Prof. Dr. Mathias Heikenwälder you increase the risk of getting cancer up to a 100-fold by drinking and smoking a lot.
If I asked you: »Do you know someone who has been diagnosed with cancer? Have you been affected yourself?« Chances are high that you would say »Yes.« to one of these questions. New insights from molecular biology show why this trend is growing stronger every year. But research also leaves us with a positive note: There is something we can do about (most of) it.
<span class="firstcharacter">W</span>hen listening to this lecture by Prof. Dr. Mathias Heikenwälder, a molecular biologist, I knew I had to share some of the findings.[1] Cancer is an uncomfortable topic, to say the least, and it can still be associated with stigma and shame. Needless to say, that shouldn’t be the case anymore these days, especially due to its high occurrence. In the USA roughly 40% of the population are at risk of being diagnosed with cancer at some point during their lifetime.[2]
Most people probably have one or two relatives who are fighting the disease or have done so – in my immediate family alone there were two cases.
One out of two
The following facts highlight why it is important to get informed since the numbers in the coming years will, unfortunately, only go up.
Some people get it in old age, others already in their 20s or 30s but these days, according to Heikenwälder, every second person in highly industrialized countries is expected to experience cancer in their lifetime, with some variation between men and women.
That is one out of two people, meaning the chance is 50% that, if you are under 50, you or I already have it or will have to deal with it sooner or later.
After researchers had examinated bodies donated to science, they found out that even patients who were categorized as »cancer-free« had lived with the disease one way or another but just didn’t know about it. It's important to note that the lifetime risk of getting cancer is not the same as the prevalence in a population. E.g., German men have a 50% chance of being diagnosed with cancer – women roughly 40% while currently 4.65 million people are diagnosed with cancer (of a population of roughly 83.3M), which is 17.85%.
The occurrence of cancer in Western developed regions like Australia, Europe, or North America is much higher (up to six times) than in less industrialized countries. But the mortality is lower due to better healthcare systems and the cancer types vary, with breast (the most common among women), prostate (the most common among men), lung, colon, and skin cancer being the most prevalent in the West[3], and other forms, like cervical cancer occurring more frequently in African countries. Generally, the risk of developing cancer for men remains a bit higher than that for women.
It’s a lifestyle choice!
Well, not entirely. But in the last 15 years, it's become clear that lifestyle and environmental factors play a far greater role than previously thought – about 90% of cancer-relevant genetic changes are acquired during life, not inherited. While so far, gene scientists understand less than 10% of the 20,000 – 25,000 genes that need examining, many of them are able to create correlations to specific mutations (e.g., between BRCA1/2 and breast or cervical cancer). But they are far from certain that they are the only or actual cause for cancer. The mutations leading to cancer that we inherit are often very aggressive and appear at an early age in the shape of childhood cancer. So, if you haven’t gotten it at an early age, chances are lower that you’ve inherited an aggressive mutation.
In a study researchers analyzed tissue samples from women born before and after 1940. They found that women with the same high-risk genetic mutation born after 1940 have nearly triple the risk of breast cancer by age 50 (67%) compared to those born before 1940 (24%). You might think: The further we come along in history the healthier we become. But that isn't necessarily the case. And the idea behind it is that our lifestyle has changed. Particularly physical activity and healthy weight during adolescence are linked to lower cancer risk – even in individuals who have a certain genetic predisposition towards these kinds of mutations.
What causes cancer?
First of all, the exact causes and effects in each individual case are always difficult to pinpoint (with certain exceptions). However, we often influence our body (or cells) negatively by coming in contact with so-called carcinogenic (cancer-causing) substances which directly affect our genomes and by being exposed to cancer promoters which increase the risk of getting cancer over time. To find out more and understand what they are, read the following:
Short Overview: Carcinogens and Cancer Promoters
Carcinogens
Carcinogens are substances that directly cause mutations in DNA. They are mutagenic,
meaning they can initiate cancer by altering the genetic material in cells after relatively short or repeated exposure.
Even brief contact with a carcinogen can be mutagenic.
Often you either need a high dose so it stays in the body longer, or you need repeated exposure.
Carcinogens don’t always result in cancer immediately,
but when they do cause a mutation, they can disrupt DNA repair systems and evade immune surveillance.
Examples are the substances in cigarettes (like incompletely burned polycyclic hydrocarbons),
UV rays from the sun, wood dust, alcohol and asbestos which directly act as carcinogens in your body.
Cancer Promoters
Cancer promoters are substances or conditions that do not directly damage DNA in most cases
but over time create an environment that helps mutated cells survive and proliferate, thereby increasing the probability
that cancer will develop.
They are not mutagenic themselves but enhance the effects of existing mutations.
Chronic exposure to promoters is often more dangerous than occasional contact with carcinogens, as promoters continually
stimulate the growth of already-damaged cells.
They act by stimulating cell division in genetically predisposed cells or by chronic irritation (such as inflammation).
They mainly act in organs exposed to environmental influences like the lungs, the gastrointestinal tract, the liver, etc.
Promoters can be very diverse and include chronic inflammation, chemical stimuli,
high-caloric intake, hormonal imbalances, persistent infections, altered gut flora and lifestyle factors like overweight
and lack of exercise.
So, carcinogens create the foundation for cancer, and promoters are substances or conditions that don’t directly damage DNA
but are chronically present and raise the risk massively.
Put both of them together and you get an extremely high risk of dying from cancer.
Visible and invisible obesity
Obesity is still one of the major drivers for cancer. Heikenwälder stated that:
The incidence of obesity and related cancers has surpassed earlier projections. As a matter of fact, now in 2025, we are beyond the estimates for 2035.
This trend is seen globally. The so-called Western diet, the McDonald's diet, which consists of the intake of large amounts of calories in a short time and is often paired with little exercise also affects countries which were previously considered less developed. Consequently, in countries such as China and India there is an incredible increase in obesity and cancer incidence.
If you have an unhealthy diet consisting of lots of processed meat, sugar, fat but few vegetables, fruit and fibers, you will increase your chance of getting colorectal cancer, also called bowel cancer which is the third most common cancer type in the world. This is probably due to the continuously negative effect such a diet has on your gut microbiome. If the trend continues this kind of cancer could be the most prevalent by 2030 among young adults.[4]
Turkey faces a similar problem. According to the WHO 32% of the Turkish population is obese – twice the EU average. The WHO expects up to 94% of the Turkish population to be obese and/or overweight by 2060 which is a mind-boggling number. Turkey recently started a new and very controversial health initiative of weighing citizens in public spaces to combat obesity. It has sparked widespread outrage and accusations of fat shaming, with critics arguing the approach is invasive and undermines individual dignity. [5, 6]
The way obesity leads to cancer: On the one hand more fat tissue means that more hormones which are produced within that fat tissue (like estrogen) circulate throughout the body and cause an imbalance. But fat tissue also binds hormones which would otherwise circulate in the body. Those bound hormones cause certain cells to lose their normal division rhythm, to divide faster, not to repair damage anymore and cause chronic inflammation. As a consequence, you accumulate a risk of developing cancer through the accumulation of mutated cells.
Another big problem is the fatty degeneration in certain organs such as the liver while the rest of the body can appear quite lean or thin, so the person might have a standard body mass index. These fatty metabolic organs strongly increase the risk of cancer – at the moment this mainly affects people in East Asian countries like China.
Alcohol and smoking (and vaping)
Smoking is still the most powerful lifestyle-related driver of cancer.
In 2022, for the first time in 20 years, the number of young people (14 – 24 years old) who smoke has risen dramatically in Germany – in some age groups up to 100%. Some sources claim that the rise happened due to the pandemic – and I’m also guessing that vaping is a related factor.[7, 8] Unfortunately, the number of excessive smokers has also risen in Germany.[9]
Tobacco smoke contains numerous carcinogens, such as polycyclic hydrocarbons, that can directly damage DNA and trigger the development of cancer. Traditional cigarette use is well understood, but vaping is a newer concern – especially among younger people. Although e-cigarettes are often promoted as a safer alternative, the long-term health effects remain uncertain. Early findings already show that some vaping ingredients can cause lung fibrosis and inflammation. Since e-cigarettes have not been as thoroughly studied as conventional tobacco products, public health experts are warning that vaping could become a major cancer risk in the coming decades.
Alcohol is always harmful to your body and poses a significant factor in cancer risk. There is no safe amount, just lower and higher risk of causing cancer by drinking alcoholic beverages. The WHO classified it as a Group 1 carcinogen, so on a similar level as asbestos, radiation and tobacco.[10] Even 5 small glasses of wine or 2 liters of beer per week are considered high-risk amounts.[11]
Health guidelines have responded to new evidence, lowering the threshold for what is considered a highly unhealthy daily amount of alcohol from 30 grams to about 20 grams (0.6 liters of beer) over the last twenty years. For women the threshold is about half that of men.
Chronic or heavy alcohol consumption alters cell metabolism and damages tissue, particularly in the mouth, throat, and liver. Over time, repeated alcohol exposure can strip away protective cell layers, making these tissues more susceptible to carcinogens. Prof. Heikenwälder put it in a nutshell:
That’s why people who drink and smoke a lot have up to a 100-fold increased cancer risk.
In addition to these direct effects, long-term alcohol use is a major contributor to the above-mentioned fatty liver disease – a condition that is now one of the fastest-growing cancer risks worldwide. Patients who drink a lot can get an alcoholic fatty liver which can lead to chronic hepatitis. That, in turn, can lead to epigenetic DNA changes which are inherited by their children. And as a result, children of this parent have a massively increased risk of developing liver fibrosis if they drink small amounts of alcohol.
Chronic cellular stress and inflammation
Chronic inflammation is one of the strongest cancer promoters, as it can both damage DNA and stimulate the growth of cells with existing mutations over time. So, it can be considered an active driver of cancer. While acute inflammation is part of the body’s natural healing process, chronic inflammation disrupts normal DNA repair mechanisms and increases the risk of genetic changes that lead to cancer.
Eating lots of processed foods[12] full of additives, having a high calorie intake, drinking alcohol, or smoking are some of the drivers for inflammation, e.g. leading to a massive change in the gut microbiome and creating the onset for colorectal cancer. When inflammation lingers, like in excess fat tissue, it pushes our cells into overdrive, creating reactive oxygen species that stress our metabolic systems and leave our genetic material more vulnerable to damage. While antioxidants were once hailed as a cure-all for this kind of cellular stress, researchers now know that the story isn’t so simple: The benefits of antioxidants depend on when and how they’re used – If misapplied, they can actually give tumors an advantage, helping them survive and even grow faster.
New healing approaches and clear paths to reducing your cancer risk
Cancer therapy has advanced dramatically over recent decades, evolving from conventional surgery, chemotherapy, and radiation to include highly targeted treatments, immunotherapies, and personalized medicine. This can result in significantly improved survival rates and quality of life for many patients who can afford it. Luckily, thousands of researchers around the world focus on finding treatments and cures every day.
Whales and mice: Insights from experiments and vaccinations
Researchers observed that whales and elephants have remarkably low cancer rates, which they attribute to a specifically slow metabolism and, in the case of elephants, a higher number of tumor suppressor genes like p53 – factors that help minimize genetic mutations and lower cancer risk. Also, in mouse studies, scientists found that removing inflammatory cells prevented fatty liver and liver cancer even when the mice consumed unhealthy diets.[13]
Because inflammation in the liver is driven in part by immune cells attracted by blood platelets (also called thrombocytes: small cell fragments in the blood that helps with clotting to stop bleeding), anti-platelet therapy with medications such as aspirin and clopidogrel is used in research models to interrupt this process, thereby reducing liver inflammation and lowering the risk of liver cancer.
On the preventive side, vaccinations – especially against common viruses like HPV, hepatitis B and C are highly effective public health measures.
Such vaccinations have the potential to prevent 100% of certain cancers, such as cervical cancer.
Infections with these viruses not only increase cancer risk but the risk increases even more if you become infected with other viruses or bacteria at the same time. The news here is that vaccination rates are still inexplicably low, e.g., in Germany with only 40% of women and girls being vaccinated. But young men are slowly getting a vaccination as well which is long overdue, since it can lower the risk of getting HPV-related cancers by 56%.[14, 15]
Again: Lifestyle as the biggest factor
However, while genetic and pharmaceutical treatments are necessary and can save lives, it became clear that a major contributor to reducing the risk of getting cancer in the first place is a healthy lifestyle. Even in the above-mentioned study, researchers subjected mice to an intermittent fasting routine (24-hour fasts twice a week involving no food, only water) which gave the liver time to detoxify and reduced both liver inflammation and cancer risk.
The WHO estimates that 50% of cancers could be prevented through lifestyle changes. Unfortunately, prevention is often under-prioritized until problems start to appear.
A healthy lifestyle includes eating a balanced diet with minimal processed foods[12] and additives, wearing sunscreen (the right way) when being outside, maintaining regular physical activity, and avoiding both smoking tobacco products and excessive alcohol consumption. This helps to prevent chronic inflammation, metabolic imbalances, and obesity and protects against cellular stress to support the body’s natural mechanisms for DNA repair and disease prevention.
Overall, the risk of getting cancer throughout our lives remains high. So, avoiding cancer altogether through lifestyle choices will be impossible in our type of societies. But according to Heikenwälder, the task of modern medicine can be a different one:
And the goal of medicine is, on the one hand, perhaps to be able to live chronically with a cancer today, with high quality of life, or to shift a cancer that would develop earlier to a time period that you would no longer live in[…]
Achieving such a goal and actually ensuring that people can live a healthier lifestyle would not only alleviate a cancer patient’s suffering but also save us tremendous amounts of money in healthcare.
<span class="headingcolor" style="display: block; text-align: center;">Thanks for your attention!</span>
<span style="word-break: normal;">Most of the information stems from Heikenwälder’s lecture. The presentation was held in German. The quotes were translated to English by me. I researched a few additional sources to add a bit more information.</span>
[12] <span style="word-break: normal;">There is no scientific consensus about the term »processed« – every kind of product needs to be treated individually. While it has been clear that the regular consumption of processed meats and Cola always raises cancer risk, there are other processed types of food which are unproblematic. For more information, see:</span></br>
[13] <span style="word-break: normal;">I do not condone animal experiments, think they are highly problematic from an ethical perspective and the direct translation of findings from, e.g., mice to humans remains highly questionable. However, I do recognize that there were major medical breakthroughs based on such research like the polio vaccine.</span>
Let me know what you think