I have railed against pseudoscientific charlatans who claim that they have the easy way to prevent or cure cancer. Generally, these snake oil salesmen try to convince you that they have some miraculous food, supplement, spiritual energy, and on and on, that can either kill cancer in its tracks or keep them from even growing in your body. Of course, none of their claims are actually supported by robust science. On the other hand, real science has 12 evidence-based methods to actually prevent cancer.
What about avoiding GMO foods because they cause cancer? Again, studies show that GMO foods have no effect on cancers. Oh, one more thing – bananas don’t have tumor necrosis factor, and the yellow fruit can’t prevent or cure cancer (but that doesn’t mean that they aren’t delicious).
Despite the absolute lack of evidence that supplements, kale, bananas, or drinking the pure waters of a glacial fed stream (which may not be an option with climate change), there are only a few things that can be done to manage your overall risk of cancer.
How to prevent cancer has been codified by the World Health Organization’s (WHO) International Agency for Research on Cancer (IARC) into 12 steps (no, not that debunked one) that are called the European Code Against Cancer.
Let’s look at cancer and how to prevent cancer.
What is cancer?
Simply, cancer is a disease in which cells of the body grow in an uncontrolled way, forming a tumor that may spread to different parts of the body. There are around 200 types of cancer, though the exact number is not precisely known, since some cancers may be related to others, or may not be cancers at all. But 200 is a good number.
All cancers are caused by mutations in the DNA of cells in the body. Most of the time, cells deal with these mutations by “fixing” the DNA. Or the mutation is so serious that the cell simply dies (it’s really one cell, and cells die in your body constantly). If the mutated cell lives and divides, the body has immune defenses against most mutations–so it’s gone before you would even know that it’s there.
Technically, with 46-68 trillions of cells in the average human body, even if a cell mutation is extraordinarily rare, the law of large numbers means that you could have literally hundreds of cancer cells living in your body, dying naturally, or being destroyed by the immune system, or not causing any problems at all. There are just so many cells in the body, and the cellular replication mechanism being slightly less than perfect, mutations will happen.
The odds against a cancer growth is even worse than I’m stating. For cancer to survive from a single cell to a mass of cells, requires nutrition (forcing the body to feed it with blood vessels). To do that, it needs another mutation of the cell. Then it needs to grow unrestricted by the normal growth control systems of the body–another couple of specific mutations. Cancer also needs to hide from the immune system, more mutations.
For a mutated cell to survive and proliferate, it could take up to 10 individual and correctly placed mutations in a cell to become cancer. Again, with trillions of cells, it becomes mathematically possible but very hard to do. Let’s look at cancer from a strictly mathematical point of view – it’s really really really really really rare. To pile up that many mutations that all are advantageous to the cancer cell are almost unimaginable.
However, outside agents, like infections, tobacco smoke, radiation (more broadly than just radioactive energy, but ultraviolet and other types of radiation), and human physiology can cause (or allow to cause) so many mutations that eventually one leads to an increase in the number of mutated cells, then a growing viable cancer.
Most cancers are relatively rare
Cancer is generally just a random event, a non-preventable risk unless an outside force causes an increase in such risk. This is why supplements or diet (other than generally consuming a diet that supplies your nutritional needs) really are just pseudoscientific nonsense to prevent cancer.
Again, we’re talking about 46-68 trillion cells in your body, so it’s impossible to consume enough supplements to reach a concentration in the blood so that all cells in the body would “see” a concentration high enough for a clinical effect on any of those cells. And the cellular mutations can’t be stopped, nor can they be reversed, by a supplement. Again, it’s essentially a random mutation and more times than not it’s fixed by the cell itself.
The USA’s National Cancer Institute lists about 150 different cancers, but they don’t list some of the very rare cancers. In fact, of those 150, really twelve make up the bulk of cancers in the world. Because people generally live longer these days, the risk (remember, it’s risk, not a yes or no) of cancer is higher – the law of big numbers gets bigger with more years of those trillions of cells have a chance at that random mutation.
Furthermore, as one ages, the cellular DNA repair system doesn’t work as efficiently. So, the risk of cancer slowly increases without any outside forces – what is generally a rare event becomes increasingly more common the older someone becomes.
Are more people dying of cancer?
More people die of cancer today, just because the population is larger and older. But the actual incidence, that is the number of people who get cancer in a fixed population, has dropped substantially. In a recent study, the authors looked at mortality rates over a 60 year period of time, and they found that:
[Cancer] mortality has been systematically decreasing among younger individuals for many decades. … the cancer mortality rates for 30 to 59 year olds born between 1945 and 1954 was 29% lower than for people of the same age born three decades earlier. … substantial changes in cancer mortality risk across the life span have been developing over the past half century in the United States. … this analysis suggests that efforts in prevention, early detection, and/or treatment have significantly affected our society’s experience of cancer risk.
Other studies, discussed here, have shown decreased mortality across all cancers as a result of greatly improved medical treatments. I know, that pretty much destroys a lot of the tropes and memes you’ve seen about cancer.
In other words, despite claims made by some pseudoscience pushers, the actual cancer mortality rate has dropped substantially. Anecdotally, people think that cancer is more prevalent and more deadly because we have contact with more people who are older than the same population 30 years ago. We used to die of other things, infectious diseases, malnutrition, pollution, and maybe wolf or bear attacks, well before cancer could arise in our bodies. Today, we all live relatively safe lives, so when we hit our 50’s and 60’s, cancer appears to be more prevalent.
There’s something else in the lower rate of cancer (and cancer mortality). It’s that the collective will of scientific research in treating or preventing cancer has brought about significant changes. We know that smoking and sunbathing have a direct causal link to some cancers. We know how to aggressively treat cancers to the point of moving some cancers from being death sentences to being successfully treatable and manageable.
Let’s make this clear. Despite what is claimed and what is believed, the absolute rate of cancer has dropped. The mortality rate from cancer has dropped substantially. It would be ridiculous for me to think that cancer can be cured (again, there are maybe 200 cancers, all of them with different pathophysiologies, etiologies, and treatments), but modern medicine is winning the war on cancer.
But there are things you can do to reduce your risk of cancer. Maybe even prevent cancer. Let’s look at IARC’s 12 points to prevent cancer.
How to prevent cancer – 12 steps
- Stop smoking tobacco. This is the number one way to reduce your risk of cancer–smoking causes lung cancer, which is the #1 cancer killer in the US and Europe. In fact, smokers are 15-30X more likely to contract and die of lung cancer than non-smokers. This isn’t something that we’ve known just for a couple of years, but since before the 1950’s. And it’s not just smoking tobacco that increases the risk of cancer–using it in other forms, such as smokeless tobacco can contribute to significantly higher risks of cancer. But the good news is that the sooner one quits using tobacco products the better the long term prognosis. Studies have shown that smokers who quit at about age 30 reduce their chance of dying prematurely from smoking-related diseases by more than 90 percent.
- Avoid second-hand smoke. Even if you avoid smoking personally, second-hand smoke has nearly the same health risk, depending on the frequency of encountering smoke. In the USA, inhaling cigarette smoke, unless one is a smoker, has become relatively rare. But in Europe, even with official bans on smoking, the risk of encountering second-hand smoke can vary by country and location from 31-90%.
- Maintain a healthy weight. Keeping one’s BMI between 18.5 and 24.9 kg/sq m can lead to an 18% lower risk of cancer. Scientifically, it is possible that other confounding factors, for example, a high-fat diet or smoking, may lead to the higher risk being associated with obesity, but the evidence seems to show a possible causal relationship. Besides, obesity leads to a much higher risk of heart disease, joint problems, and dozens of other medical issues, so that’s like a super bonus.
- Be physically active. Closely related to #3. Being physically active helps maintain a healthy weight, but it may have other benefits with respect to cancer risks.
- Eat a healthy diet. No, this does not mean that eating kale and soy milkshakes are going to reduce the risk of any cancer. However, as IARC states, eating a diet filled with whole grains, fruits, and vegetables while avoiding high fat and high sugar foods will help with #3. There’s no solid evidence that a particular diet will reduce the risk of cancer, BUT a healthy diet can lead to weight loss and maintaining the appropriate BMI.
- Avoiding alcohol. Alcohol, even moderate amounts, can lead to a significant increase in the risk of certain cancers. In fact, alcohol consumption causes around 3% of cancer deaths in the USA. And not to repeat a point – reduced alcohol consumption could lead to weight loss and a healthy BMI.
- Avoid the sun (and UV tanning beds). Ultraviolet (UV) light, mostly sunlight, can damage surface skin cells leading to some very serious cancers. Although one form of UV light, UVB, is necessary for the production of vitamin D, an essential nutrient, excessive UVB can lead to permanent damage to cells. Getting vitamin D through supplements or foods is probably healthier than sunlight (yes, I recommended a supplement, because I always make an exception for valid medical reasons like chronic disease or malnutrition).
- Avoid pollutants. Some believe that all “chemicals” are bad, even though there really are a just a few that are known carcinogens and should be avoided. The current “chemophobia” of many people is borderline ridiculous, because even known carcinogenic chemicals can only increase the risk of cancer at certain levels, meaning they could be safe in extremely low amounts (dose makes the poison in toxicology). It’s all about the dose. It’s impossible to avoid all man-made and natural chemicals (there are more so called natural substances that are carcinogenic than humans could possibly invent), but avoiding polluted water and air, or being careful in a workplace that has a lot of chemicals, will help manage the risk. Remember, the theory (from a scientific perspective) that cancers arise from frequent mutations means that the risk increases as the number of mutations increase. The world isn’t perfect, but it’s not either no chemicals or “we’re all going to die of cancer” type of false dichotomy.
- Avoid radiation. This risk is really just radon gas, an invisible radioactive gas that is found in many homes in certain geological areas. There are other risks to some people who may be exposed to radiation in certain careers. Radon can be easily detected, and easily removed from the air, but it does require testing. Many people would not rent or buy a home without having it thoroughly tested for radon gas – I wouldn’t.
- Breastfeed your baby. Women who breastfeed their babies for extended periods of time reduce their risk of breast cancer in later life when compared to women who do not breastfeed. In fact, the reduction in risk of breast cancer is about 4% for every 12 months of breastfeeding (which can be summed up over more than just one baby). This reduction in risk is above and beyond the reduced risk of breast cancers from having a baby.
- Get your HPV and hepatitis B vaccines. It’s ironic that the pseudoscience pushers are solidly anti-vaccine, yet promote pseudoscientific and unsubstantiated “prevent cancer schemes” that are useless. On the other hand, two vaccines, for hepatitis B and HPV, actually prevent more cancer than drinking 100 kale shakes. The hepatitis B vaccine has caused a 96% decrease in hepatitis B infections, which are related to over 50% of the cases of a liver cancer, hepatocellular carcinoma. The HPV vaccine blocks infection of the human papillomavirus which is linked to several types of terrible cancers. Despite the myths, the HPV vaccine is incredibly safe, possibly the safest vaccine of all vaccines (which are all extremely safe). Seriously, one could swallow hundreds or thousands of supplements, and these vaccines will actually do more to prevent cancer than those overpriced supplements will ever do. And yes, the scientific evidence supports that statement.
- Get screened for cancer. There are diagnostic screenings available for a huge number of cancers. One can get a colonoscopy for hard to detect intestinal cancers. There are simple screenings for cervical and prostate cancer. There is imaging for small tumors on internal organs. There are blood tests for others. Yes, getting a colonoscopy, if you’re age-appropriate, is not fun. But it’s not dangerous, and it can detect cancer very early, before it kills. Once again, screening is much more effective than the mythical miracle kale shake.
Prevent cancer – the TL;DR version
- Preventing and treating cancer is not as easy as the “natural food and supplement” people claim. It’s because they oversimplify and understate the biology of cancer. They want people to think “take this pill, don’t worry any more.”
- Cancer incidence and mortality are dropping. Modern, science-based medicine is the cause.
- Stop smoking.
- Lose weight.
- Get out of the sun.
- Don’t drink carcinogens.
- Make sure your house has no radon.
- Breastfeed your baby (if you’re a woman of course) for as long as possible.
- Get the hepatitis B and HPV vaccines.
- Get regular screenings for cancer.
I know. It’s not really that easy, probably not as easy as downing $20 of supplements that will just be passed in the urine. But if any of you really want to reduce your risk of cancer, then you’ll have to do this. Or just drink your kale shakes. At least that will make you lose weight.
Editor’s note: This article was originally published in October 2014. The article has been updated to address some grammar and spelling errors, fix broken links, improve the recommendations, and reticulate some bad splines.
- Doll R, Peto R, Boreham J, Sutherland I. Mortality in relation to smoking: 50 years’ observations on male British doctors. BMJ. 2004 Jun 26;328(7455):1519. Epub 2004 Jun 22. PubMed PMID: 15213107; PubMed Central PMCID: PMC437139.
- Edwards BK, Noone AM, Mariotto AB, Simard EP, Boscoe FP, Henley SJ, Jemal A, Cho H, Anderson RN, Kohler BA, Eheman CR, Ward EM. Annual Report to the Nation on the status of cancer, 1975-2010, featuring prevalence of comorbidity and impact on survival among persons with lung, colorectal, breast, or prostate cancer. Cancer. 2014 May 1;120(9):1290-314. doi: 10.1002/cncr.28509. Epub 2013 Dec 16. PubMed PMID: 24343171; PubMed Central PMCID: PMC3999205.
- El-Serag HB, Rudolph KL. Hepatocellular carcinoma: epidemiology and molecular carcinogenesis. Gastroenterology. 2007 Jun;132(7):2557-76. Review. PubMed PMID: 17570226.
- Kort EJ, Paneth N, Vande Woude GF. The decline in U.S. cancer mortality in people born since 1925. Cancer Res. 2009 Aug 15;69(16):6500-5. doi: 10.1158/0008-5472.CAN-09-0357. PubMed PMID: 19679548.
There are three ways you can help support this blog. First, you can use Patreon by clicking on the link below. It allows you to set up a monthly donation, which will go a long way to supporting the Skeptical Raptor
You can also support this website by using PayPal, which also allows you to set up monthly donations.
Finally, you can also purchase anything on Amazon, and a small portion of each purchase goes to this website. Just click below, and shop for everything.