Do B Vitamins Cause Lung Cancer?
Vitamin B Linked to Increased Lung Cancer Risk
This headline is just one example of many that spread across the internet earlier this week.
The bold message refers to a study that was published in the Journal of Clinical Oncology, which in fact did find an association between b-vitamin supplementation and increased lung cancer risk.
Do B vitamins really increase cancer risk?
In this article we’ll explain how you should interpret these results and why inflammatory headlines should be taken with a (large) grain of salt.
Do Vitamins Increase Cancer Risk?
The first thing you need to know about this study is that it was a cohort study.
This means a group of participants were recruited and surveyed on various lifestyle and health measures. By definition this type of study can only find associations, not causations -- an important point.
77, 118 participants between the ages of 50 - 76 years old were recruited for the Vitamins and Lifestyle (VITAL) study between 2000 and 2002, with data being recorded for the next 10 years.
The study first asked people about their vitamin and supplement use, then, researchers looked at the data from that survey and were able to link it to a cancer registry of the same area.
Of that initial population, 808 individuals were found to have lung cancer -- these were the people being studied.
So, the researchers decided to compare this information against vitamin and supplement habits to see what they could find.
They found that those who supplemented with vitamin B6 and or vitamin B12 well above the RDA levels were associated with a significantly greater risk of lung cancer.
Related content: 5 Supplements to Replace Your Multivitamin
5 Points Missing From the Headlines
If you've been a part of the Natural Stacks tribe for a while, you probably know there's more to the picture than the headlines convey. This latest controversy is a prime example of when the media misrepresents the facts. Here are 5 points you need to know that will give you a better understanding of what this study actually means.
Point 1: Cancer risk was only found in men
When breaking down the numbers, the researchers found a significant increase in cancer risk only in males, not females.
The statistical analysis showed that men who took more than 20 mg of vitamin B6 per day (compared to 1.7 mg per day, the RDA) had 80% higher risk of developing lung cancer.
Men who took more than 55 micrograms of vitamin B12 (2.5 micrograms is the RDA) had a 98% increased risk of lung cancer.
These numbers were calculated from the highest dosages in the study, but the association was only found in men.
Related Content: Cancer as a Metabolic, Mitochondrial Disease
Point 2: Many of the subjects were smokers
All of the data in this study were collected from people with lung cancer -- many of whom were smokers.
Not surprisingly, the highest risk of cancer was found in smokers. Furthermore, that risk was even higher in men who took the highest dosages of both B vitamins simultaneously.
Point 3: There is really no way to know
The nature of this study was epidemiological; it was based on population data, not clinically-controlled data, which means the best conclusion we can draw is a correlation between vitamin intake and cancer risk.
Anything else is pure speculation.
Did men have a greater risk of cancer because they were smokers and knew they had an increased risk? If so, did they take vitamins to try to stave off that risk?
Or perhaps participating in the study was attractive to individuals who were already diagnosed with cancer, which made them more likely to do anything and everything that might help (i.e. taking massive doses of vitamins for a study).
The point is, you can’t draw finite conclusions from this study.
Instead, results like this are meant to raise more questions and opportunities to answer those very questions in future studies that can help fill in the blank in the available research.
Point 4: False positives
Double-blind, randomized placebo controlled trials are considered the gold standard in research because they are designed to minimize confounding variables as much as possible.
This study, on the other hand, has a host of variables and multiple analyses on the same data set. In other words, the more variables and the more pieces of data in a study, the greater the chance for false positives and blurred conclusions.
This means the results can easily be due to chance and aren’t always reliable.
The authors in the study do acknowledge this major limitation, and even close out the paper with recommendations for future research to dig deeper into the subject.
Point 5: Cancer cells need vitamins too.
Every cell in your body needs energy, and that includes cancer cells.
Unlike normal cells, cancers are even more energy-demanding. They are highly metabolically active and it’s possible that by taking super high levels of vitamins, you could be feeding your cancer as well.
This “metabolic quirk” of cancer cells is a a recent therapeutic target of low-carb and ketogenic diets because they are potential strategies to help starve cancer cells of glucose.
And by effectively denying them the energy they need to survive and grow, they die.
Ingesting vitamins upwards of 10x the recommended daily allowance, you may be adding fuel to the fire.
When it Comes to Headlines Like This, Here's What You Should Remember:
Whenever you see the words "prospective", "cohort", "epidemiological" or just about anything besides "randomized, controlled", it is impossible to determine a cause and effect relationship.
Maybe high dose b vitamins interact with certain pathways involved in lung cancer metabolism, maybe not. What this study gives us are clues, not answers.
Ultimately, taking high doses of anything (vitamins, supplements, even water) is probably not a good idea.
Get your levels tested and target those levels with proper supplementation, don’t just take things blindly.