Nobel laureate Otto Warburg proved that cancer is the result of an "anti-physiological way of life"?

We often witness such false theses being put forward on social media, where much of the content is not subject to any fact-checking. What do experts say about this topic? See the article by Agence France-Presse, a multilingual, multicultural news agency whose mission is to provide accurate, balanced and impartial continuous reporting wherever and whenever news happens in the world. Our oncologist Dr. Davor Kust also spoke for the article.

We are reprinting the article in its entirety, and you can find the original at the link.

Otto Heinrich Warburg, a German physiologist, biochemist and Nobel Prize winner, did not "discover that cancer is the result of an anti-physiological lifestyle", as is inaccurately claimed in an article that has been shared on the Internet and social networks in Croatian and Serbian for at least a decade, most recently in November 2024. According to a scientist who is a specialist in his work, Warburg did not allude to the "acidity" of food in his scientific papers, nor did he mention lack of physical activity as a cause of cancer. Contrary to the article's claims, acidity is not a prerequisite for tumor growth, she told AFP. Scientists and doctors also dismiss as false the claim on social media that chemotherapy worsens cancer and say it saves or prolongs life. While poor diet and physical inactivity are risk factors for some types of cancer, consuming alkaline foods will not make the body less acidic because the food we eat is not decisive for the pH levels in our bodies, according to relevant experts and research.

"The cause of cancer was discovered by Otto Heinrich Warburg back in 1923, protection against this fatal disease is very simple," begins a Facebook post dated November 21, 2024, claiming that the 1931 Nobel Prize winner discovered that cancer is caused by an "antiphysiological diet," defining it as food that acidifies the body. The lengthy post suggests that cancer patients should eat alkaline foods that reduce the body's acidity, and that chemotherapy further acidifies the body, which worsens cancer.

The post was shared more than 32,000 times in a month, with many users praising the alleged clarity of the instructions or lamenting the modern lifestyle and diet, which they see as the main cause of cancer.

Similar claims have appeared several times in recent years. A Croatian-language article, archived in June 2013, published on a website promoting "alternative medicine" and selling "natural" products and supplements, contained most of the claims in the latest post. A similar article was also published on another Croatian page in 2019, and was shared on Facebook as early as April 2023. The claims also appeared on a Serbian page dedicated to "natural" medicine in July 2022, and were still being shared on Facebook in early 2023.

Image 1. Otto Warburg.

Otto Warburg's work has been misinterpreted or misrepresented before. AFP's Serbian fact-checking service refuted claims in 2020 that cells become cancerous due to a lack of oxygen, as well as claims that cancer is caused by an "anti-physiological lifestyle" in 2023. AFP Factuel in French refuted similar claims in 2022 that Warburg said that "no disease, including cancer, can survive in an alkaline environment."

Multiple investigations by AFP have found that the cancer claims in the article are false. There is no evidence that Dr. Warburg ever spoke of an "anti-physiological lifestyle" or alluded to "acidity of food" or lack of physical activity as causes of cancer, as the article claims. Experts agree that acidity is not a prerequisite for the development of cancerous cells, and there is no evidence that increased acidity increases the risk of developing cancer. While it is true that cancer cells can grow better in an acidic environment, the body's acidity level is not determined by food intake, scientists and doctors say.

Otto Heinrich Warburg was a German physiologist and biochemist born in 1883. His work on cellular respiration was groundbreaking in the study of cancer cells. He received the Nobel Prize in 1931 for "his discovery of the nature and mode of action of the respiratory enzyme."

According to Angela Otto, an associate professor at the Faculty of Bioengineering in Munich, who has long studied Dr. Warburg's work, there is no record of him linking the consumption of any type of food or physical activity to cancer.

"I have found no evidence that Otto Warburg used the term 'antiphysiological lifestyle' or anything similar in his scientific papers," Angela Otto wrote in an email to AFP in January 2023. "In his later years (after 1956) he mentioned environmental carcinogens as possible ('secondary') causes of cancer, leading to respiratory damage, and then to anaerobic glycolysis (fermentation of sugar equals lactate production) as the 'primary' cause of cancer," Otto said, adding that "acidity is not a prerequisite for tumor growth."

In addition, Warburg "did not mention the 'acidity' of food, nor did he mention lack of physical activity as causes of cancer," she added.

Contrary to the publication's claim that cancer cells cannot survive in the presence of oxygen, Angela Otto points out that they do need oxygen:

"Over the past ten years, it has been proven that cancer cell metabolism is very flexible and adaptable (tumor plasticity)—much more than Otto Warburg could have predicted 60 years ago. Moreover, cancer cells 'survive' in the presence of oxygen—they need it!—and would die in the absence of O2 (anoxia)," she explained.

"That is to say: cancer cells 'BREATHE' oxygen and survive in the presence of high (normal) oxygen concentrations." Tumor cells cannot survive on glucose alone—they need other nutrients as well—"and CANNOT survive without oxygen!" she emphasized. (All caps and boldface added by Angela Otto.)

Acidifying Foods Don't Cause Cancer

The post also claims that a diet "consisting largely of acidifying foods" contributes to the "acidic environment" that causes cancer, concluding that people should avoid "foods that acidify the body."

Scientists measure the acidity of aqueous solutions using a scale called pH, which ranges from 0 (highly acidic) to 14 (highly alkaline), with a pH of 7 indicating a neutral solution (neither acidic nor alkaline).

"Some research has shown that an acidic environment can help cancer cells grow. Hence the idea that a diet rich in alkaline foods (high in pH) and low in acidic foods would increase the body's pH (making the body more alkaline) and prevent or even cure cancer," Maria Petzel, a clinical nutritionist at the University of Texas MD Anderson Cancer Center, said in an April 2018 interview for an article published on the center's website. However, "it's important to note that these are laboratory studies of cancer cells that do not reflect the complex nature of tumor behavior in the human body.

Debunking the myth that the so-called "alkaline diet" can prevent cancer, she said: "The food you eat cannot change the pH level in your blood. The body's pH is a very tightly regulated system. If you change your diet, you can see changes in the pH of your saliva or urine because these are waste products, but you can never eat enough that it really affects your blood."

Miloš Babić, a molecular biologist, neurobiologist and director of research at Celldom, a company that studies the function of individual cells, explains that the human body is "always slightly alkaline, with a pH between 7.35 and 7.45, which is very carefully controlled by the lungs and kidneys."

"If this is disrupted, serious problems arise immediately, there is no waiting for cancer to develop. "If there was a food that made your body acidic, you would be in the hospital within a few hours of eating it and probably wouldn't get out alive. Literally nothing that can be called food or drink can make your body acidic," Babić told AFP in February 2023.

The pH value of blood is around 7.4, a neutral state. "Any significant deviation from that value is dangerous," Angela Otto also explained to AFP in April 2021. "A high alkaline value would kill cells," she added.

Nutritionist Dominik Stanković also said in an email to AFP on December 18, 2024, that there is no evidence that any type of diet can change the body's natural acidity level, and that excess acidic or alkaline elements released during digestion are quickly filtered out through the lungs and kidneys.

"This constant filtering creates 'waste fluids' that are removed from the body through, for example, urine, saliva and sweat," Stanković said. "The pH of these fluids can vary depending on what we ingest. Of course, the pH of these secretions does not reflect the pH of our blood."

According to Stanković, increased consumption of so-called "alkaline" foods is recommended not because they would alkalize the blood and treat cancer, but because of other ingredients that have proven beneficial effects on our bodies, such as specific nutrients.

"The solution to the fight against cancer is not expensive books with diets full of unnecessary restrictions, unnecessary supplements and alkaline waters that are being used today under the pretext of 'alkalization of the body'," said Stanković.

"The best thing we can do in terms of nutrition, according to current scientific research, is to include a lot of plant-based foods, aiming for at least five servings of fruits and vegetables per day, use whole grains over refined grains, include beans/legumes more often, and limit meat consumption to 2-3 times a week. And of course, occasionally and in moderation enjoy those nutritionally poor foods like sweets or pizza. Because the psychological component of nutrition is also very important. "

A 2016 meta-analysis published in the British Medical Journal, which reviewed 252 research papers on the effectiveness of alkaline diets in fighting cancer, concluded:

"Despite the promotion of alkaline diets and alkaline water in the media and by marketers, there is almost no current research to either support or refute these ideas... Public promotion of alkaline diets and alkaline water for the prevention or treatment of cancer is not justified."

In addition, Babić explains that "today we know quite clearly how cancer originates and develops (changes in genes that lead to the uncontrolled multiplication of our own cells and which enable them to evade the immune system), which has absolutely nothing to do with acidity, oxygen, or any other such factor".

"Today, through genetic analyses, it is possible to establish exactly which genes have changed and led to cancer - mutations produced by excessive exposure to UV radiation, smoking, carcinogenic substances and similar factors," he added.

On its cancer factfinder website, "Cancer factfinder," the Harvard School of Public Health explains that "there are no human epidemiologic studies examining the relationship between pH and cancer."

"There is no laboratory evidence that an acidic pH increases the risk of cancer. While it is true that cancer cells grow well in an acidic environment, the food you eat does not affect your body's pH levels. Factors that affect your body's pH include fluid loss, electrolyte levels, and organ function."

Benefits of chemotherapy confirmed in clinical studies

One of the claims in the publication is that "chemotherapy does not cure, but worsens the acidity of the body" and thus cancer.

Oncologist Davor Kust, head of the Anova Polyclinic and founder of the oncology network onkologija.net in Croatia, told AFP on December 23, 2024 that medicine had long since abandoned such theories, adding that it would be great if the disease were that simple.

"Treatment in oncology today is based on quite serious trials, drugs are not given just because someone thought of them," said Kust. "Research is conducted on very large numbers of people - one group receives the best treatment up to that point, and the other something new. All oncology therapies have undergone quite strict and uniform clinical trials, which provide quite objective and realistic data that can be trusted."

In his article on chemotherapy, Kust explains that it can be used to treat cancer, reduce the risk of the disease coming back, slow the growth of the cancer or reduce some of its symptoms. "The idea that people can be cured by changing their diet, I'm afraid that's not possible," Kust told AFP. "Diet can help, but it can't cure."

In a Yale Medicine article on chemotherapy, medical oncologist Joseph Paul Eder describes the progress in fighting cancer with this method. "Cancer chemotherapy has evolved from the last resort 60 years ago to a treatment that can cure patients or significantly extend their lives today, often with far fewer side effects than the original drugs of a few decades ago," Eder said.

Physical inactivity is a risk factor, not the main cause of cancer

"The only true thing in the whole story is that physical activity and good nutrition really reduce the probability of cancer (though not to zero, especially in modern society where even the healthiest people are exposed to smog and cigarette smoke)," says Babić.

He explains that active people who eat well, with a lot of plant foods and vegetables, among other things, have better circulation, a healthier immune system that better removes cancer cells in the early stages, less fatty tissue, better replacement of old cells in which mutations accumulate the most.

"All of this together makes the probability of cancer, as well as the probability of many other diseases, lower. It is good and useful to be active," says Babić.

The Cancer factfinder site states that "there is strong evidence that higher levels of physical activity are associated with a lower risk of several types of cancer. Much of this evidence has been published in 'meta analyses', or statistical comparisons of multiple studies looking at similar questions."

In its information on the relationship between physical activity and cancer, the National Cancer Institute (NCI) states that people who are the most physically active have a 12-21% lower risk of developing some types of cancer than those who are the least active.

Additionally, although there is less research on sedentary behavior and cancer risk than on physical activity and cancer risk, sedentary behavior - sitting, lying down, or lying down for extended periods of time (except while sleeping) - may also be associated with an increased risk of some types of cancer, the NCI says.

According to the 2018 Expert Report on Physical Activity and Cancer Risk, published by the World Cancer Research Fund International, a London-based research network that examines how diet, weight and physical activity affect the risk of developing and surviving cancer, there is strong evidence that physical activity reduces the risk of colon, breast (post-menopausal) and endometrial cancer, and that more vigorous physical activity reduces the risk of breast cancer before and after menopause.

According to the European Code Against Cancer (ECAC) – a set of 12 recommendations developed by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO), at the initiative of the European Commission – adherence to these recommendations can prevent or avoid almost half of all cancer deaths in Europe.

Recommendations include avoiding smoking and exposure to tobacco smoke, maintaining a healthy body weight, regular physical activity, a healthy diet (whole grains, vegetables and fruits, limiting sugar and fat intake, red meat and foods high in salt, and avoiding processed meats), stopping or limiting alcohol consumption, avoiding sunlight and using sun protection, avoiding carcinogens in the workplace, reducing radiation exposure, breastfeeding children if possible, vaccinating children against hepatitis B and HPV, and participating in organized screening programs for colon, breast and cervical cancer.

Continue reading:

Cancer is the body's defense agains toxins?

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