Folic Acid and Cancer

Written by Dr. Steve Chaney on . Posted in Drugs and Health, Supplements and Health

Does Folic Acid Increase Cancer Risk?

Author: Dr. Stephen Chaney


folic acid and cancerYou’ve seen the headlines. “Folic Acid Supplements May Increase Colon Cancer Risk in People Over 50” and “Folic Acid Supplements May Increase Prostate Cancer Risk in Men”. And I’ve seen articles telling people over 50 that they should take their multivitamin tablets every other day to avoid getting too much folic acid.

I’ve even heard of doctors telling their patients to avoid any supplements containing folic acid. So what’s the truth?  Is there a cause and effect relationship between folic acid and cancer?

Why Do People Say Folic Acid Increases Colon Cancer Risk?

Perhaps a bit of historical perspective is in order. A number of population studies had suggested that high intakes of folic acid might protect against cancer, especially colon cancer, so several placebo controlled clinical studies were initiated to test that hypothesis. Those studies had mixed results, with some suggesting that folic acid might be protective and others suggesting that it had no effect. None of those studies suggested that folic acid supplementation increased the risk of any kind of cancer.

In 1998 mandatory folic acid fortification of grain products was introduced. In addition, the number of Americans taking supplements with folic has increased dramatically in recent years. As a consequence total intake of folates (folic acid from fortified foods and supplements plus folates naturally found in foods) has increased significantly. By one estimate blood levels of folates have increased 2.5-fold between 1994 (before fortification) and 2000 (after fortification).

So it was just natural to ask if this increase in folate intake might have unintended consequences. And one clinical study seemed to suggest that it might (JAMA, 297: 2351-2359, 2007)

That study looked at colorectal adenomas and reported high folate intake was associated with an increased risk of more advanced adenomas. [It is important to note that adenomas are benign tumors. They are thought to be precursors to colorectal cancer but they are not actually cancerous].

Some experts immediately started warning about getting too much folic acid in the diet – with some going so far as to warn that people over 50 should only take a multivitamin every other day.

And several papers were published speculating on how differences between the way that folic acid and the other folates were utilized by the body could cause folic acid to increase the risk of colorectal cancer while naturally occurring folates decreased the risk.

Let me put this into perspective. Any good scientist knows not to trust a single clinical study. Individual clinical studies can provide misleading results. Sometimes it is possible to pinpoint the cause. For example, the study may have been poorly designed, may have included a non-representative population group, or the statistical analysis may have been incorrect. But, sometimes we never know why an individual clinical study came to the wrong conclusion.

folic acid and colon cancerThat is why good scientists generally say that more studies are needed and base their recommendation on the preponderance of many studies rather than a single study.

The problem was that all of this hype and hypothesizing about folic acid increasing the risk of colon cancer was based on a single study, and that study didn’t actually look at colorectal cancer. A Norwegian study four years later found no evidence for increased colorectal cancer at folic acid intakes of up to 800 ug/day (AJCN, 94: 1053-1062, 2011) – but it was largely ignored.

The background is similar for the claims that folic acid may increase prostate cancer risk. When a small meta-analysis that included some, but not all, published clinical studies suggested an increased risk of prostate cancer, some experts went as far as to suggest that men should completely avoid supplements with folic acid.

The problem is that even meta-analyses can be misleading if they only examine a small sub-set of clinical studies because they can be unduly influenced by a single misleading clinical study.

Does Folic Acid Increase Colon Cancer Risk?

Should We Avoid Supplemental Folate?

The American Cancer Society decided to resolve the uncertainty about folic acid intake and colon cancer risk once and for all (V.L. Stevens et al, Gastroenterology, 141: 98-105, 2011). They designed the study to answer two very important questions:

1) Has the increased folate intake by Americans over the past several years actually increased their risk for colorectal cancer?

2) Does the chemical form (folic acid versus folate) influence its effect on colorectal cancer risk?

And this study had two very important firsts:

1) This was the very first study to investigate the association between folate intake and colorectal cancer entirely in the post-fortification period.

2) This was also the very first study to separate out the effects of folate and folic acid on colorectal cancer risk.

And it was a very large study. They followed 43,512 men and 56,011 women aged 50-74 for 8 years between 1999 and 2007.

Folate intakes from food ranged from 175 ug/day to 354 ug/day while folic acid intakes from food fortification, supplements and multivitamins ranged from 71 ug/day to 660 ug/day. Total folate (both naturally occurring folates and folic acid) intakes ranged from 246 ug/day to over 1014 ug/day.

When they analyzed the data they found that high intakes of neither folic acid nor natural folates were associated with any increased risk of colorectal cancer. In fact, they found high intake of total folates was associated with a significant decreased risk of colorectal cancer.

Does Folic Acid Increase Cancer Risk?

folates help prevent cancerWhat about prostate cancer and other types of cancer? Could folic acid increase the risk of other cancers? To resolve this issue once and for all, a group from Oxford University (Clarke et al, The Lancet, doi: 10.1016/S0140-6736(12)62001-7) did a meta-analysis of every study published through 2010 that compared folic acid supplementation to a placebo, lasted at least 1 year, included at least 500 people and recorded cancer incidence – some 13 studies with over 50,000 participants.

The results were clear cut. As for folic acid and cancer, supplementation did not increase the overall cancer risk, and when the incidence of individual cancers was analyzed, folic acid supplementation did not increase the risk of developing colon cancer, prostate cancer, lung cancer, breast cancer or any other site-specific cancer.

To put this in perspective the average dose of folic acid used in these clinical studies was 2 mg/day, which is 5 times the RDA and 5 times the dose in most supplements. And one of the clinical trials used 40 mg/day, which is 100 times the dose in most supplements.


The Bottom Line

Forget the warnings and the hype. You can be confident that folic acid does not increase the risk of colorectal cancer, prostate cancer, or any other kind of cancer.

  • The American Cancer Society recently performed a very large clinical study looking at the effect of folic acid intake from supplements and folate intake from foods on colon cancer risk. That study found that high intakes of neither folic acid nor natural folates were associated with any increased risk of colorectal cancer. And, they found high intake of total folates was associated with a significant decreased risk of colorectal cancer.
  • The authors of that study concluded: “The findings of this study add to the epidemiological evidence that high folate intake reduces colorectal cancer risk.” “More importantly, no increased risk of colorectal cancer was found, suggesting that the high levels of this vitamin consumed by significant numbers of Americans should not lead to higher incidence rates of this cancer in the population.”
  • A second meta-analysis of every clinical study looking at folic acid intake and cancer risk through 2010. The results of that study were clear cut. Folic acid supplementation did not increase the overall cancer risk, and when the incidence of individual cancers was analyzed, folic acid supplementation did not increase the risk of developing colon cancer, prostate cancer, lung cancer, breast cancer or any other site-specific cancer

Like any good scientist I am aware that future studies could change our understanding, but for now I am confident in saying that there is no credible evidence that folic acid supplementation increases your risk of any kind of cancer. If the science changes, I will be the first to let you know.

But it will be really interesting to see how long it takes all those web sites, blogs and so-called “experts” to acknowledge that the science has changed and they should stop issuing false warnings about folic acid supplementation.


These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Latest Article

Calf Cramps Remedy

Posted February 20, 2018 by Dr. Steve Chaney

Don’t Let A Leg Cramp Stop You Short

Author: Julie Donnelly, LMT – The Pain Relief Expert

Editor: Dr. Steve Chaney


calf cramps remedyGetting a leg cramp while you are running can be the “straw that broke the camel’s back.”  If you don’t treat it properly and quickly when it is happening, you may limp to the finish line, and you can suffer from its effects for days afterward.  I will show you the best calf cramps remedy below.  First, let’s go over spasms and muscle cramps.

A spasm and a cramp are similar because it’s a shortening in the muscle fiber, but that’s where the similarity ends. A spasm is a slow-forming shortening of a group of fibers that tie up into a knot in the muscle. You can feel a spasm with your fingertips, it feels like a bump as you slide along the full length of the muscle. With a spasm, as you press down and slide, it doesn’t hurt until you get to the spasm, and then it can really hurt. But then it stops hurting as you slide off the spasm. A spasm refers pain to the insertion points of the muscle and frequently doesn’t hurt where the spasm has formed (that is, until you press on it).

Why Do Your Muscles Cramp?

calf cramps remedy muscle crampsA cramp (Charlie horse) is when all the fibers of the entire muscle suddenly and violently contract. The muscle will quickly shorten and can go into a huge knot, or it will just totally shorten.

Usually a cramp happens in your calf muscle, although it can happen to any muscle in the body.  Your calf is comprised of two major muscles, the gastrocnemius and soleus. The gastrocnemius, which is shown in this graphic, originates behind your knee and inserts into your Achilles tendon.

Visualize the muscle suddenly shortening, pulling up on your Achilles tendon, and becoming a mass of tight knots through the entire muscle.

Muscles have an “all or nothing” response.  This means that when a muscle fiber contracts, it will shorten 100% of its length.  It never starts to shorten and then make a U-turn and lengthen.  A cramp is seriously painful, and if you try to stretch it out as it’s happening, you can tear the muscle fibers. In fact, that’s the reason it hurts for sometimes days after the cramp.

A Calf Cramps Remedy You Can Administer Yourself

calf cramps remedy squeezeThe best thing to do is to squeeze the two ends of your calf muscle together, which will help the cramp complete as quickly as possible. This will hurt, but for less time than the normal cramping process.  Hold your calf tightly, as shown in this picture, and continue to press the two ends toward each other.

Hold it until you can breathe normally (about 30-45 seconds), and then release. Breathe for a minute or so, and then push the two ends together again.  This second time won’t hurt, you are only doing it to make sure that all the fibers have completed the contraction.

calf cramps remedy hold sittingOnce you have stopped the cramp, don’t stretch…yet. You need to flush out the hydrogen ions (AKA lactic acid) that rapidly built-up in the muscle during the cramp.

There are many ways to self-treat your calf. If you are out on the road you can either sit on a bench or lie on the ground and put the sore calf onto your opposite knee.  Press down and hold the pressure for 30 seconds. Then deeply press along the muscle going from the back of your knee toward your ankle.

calf cramps remedy opposite footYou can also use your opposite heel and press deeply, straight into your calf.

Start at the top of the muscle and move down toward your ankle. Stop whenever you come to a point that is especially painful. The point should be close to the area shown in this picture.

Hold the pressure for 30-60 seconds, or until it doesn’t hurt anymore.  Release, and then repeat 2-3 times.

Complete this self-treatment by squeezing your calf muscle, like you are wringing out a wet towel.  This will force blood into your muscle and get your circulation moving again.

Proof That My Treatments Work

I once taught this technique at an Ironman Triathlon during a 15-minute session I was giving to the triathletes.  Several days later a triathlete emailed me and told me that he had a cramp as he was running, and he did the treatment I’d taught him.  It cost him a few minutes (he wasn’t in the top three, so the time loss wasn’t a huge issue) but he was able to get up and get back to running, totally without pain.

About a mile later he got a cramp in the other leg, but he automatically started to just stretch it like he’d always done before.  He ended up limping all the way to the finish line, and days later it was still hurting.  He wanted to let me know that my cramp treatment really worked great.  This was especially helpful because I’d always wondered what body chemistry did to the outcome of treating a cramp, and here I found out that chemistry wasn’t involved in the treatment of the muscle fibers.

What To Do After The Calf Cramps Remedy

If the cramp happens during a race or athletic event, knowing how to stop it, and these quick massage techniques, will get you back into the game. But it hasn’t totally resolved the issue. Finally, when you have the time to be detailed (after the race, in the evening, etc.), it is important to work out all the spasms and then stretch properly.

When you are treating the muscles afterward, I suggest you consider getting an analgesic cream that goes way deep into the muscle fibers. Use it when you are massaging the muscle, but don’t put it on before you play, run, or before/after a shower because it will go too deep into the muscle and burn like crazy. After you do the treatments, use ice &/or arnica gel (get it at a good health food store) to heal the bruised muscle fibers and help with pain and swelling. Arnica is fantastic, it’s an amazing homeopathic remedy that has been around for ages and really works.

Naturally you will also want to make sure you hydrate properly and that your diet, vitamins and minerals are all in balance.

calf cramps remedy bookCramping is a common problem athletes face, but with a little bit of effort you can prevent muscle injury and get back in the race quickly!

You can find the full treatments for your muscle cramps by going to my book, Treat Yourself to Pain-Free Living . This book has treatments for your entire body, from your head to your feet.  YOU are your own Best Therapist!  Stop pain quickly and easily with self-treatments you can do anytime, anyplace.

Wishing you well,

Julie Donnelly

julie donnelly

About The Author

Julie Donnelly is a Deep Muscle Massage Therapist with 20 years of experience specializing in the treatment of chronic joint pain and sports injuries. She has worked extensively with elite athletes and patients who have been unsuccessful at finding relief through the more conventional therapies.

She has been widely published, both on – and off – line, in magazines, newsletters, and newspapers around the country. She is also often chosen to speak at national conventions, medical schools, and health facilities nationwide.


These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.