Folic Acid: Risks or Myths?

There are theoretical risks for isolated folic acid in high doses. But these supposed risks fly in the face of established science and are controversial, not at all conclusive. There is also confusion over the significance of the supposed risks of high dose isolated folic acid in test tube and animal studies which do not identify a danger for moderate level supplementation - or even higher dose supplementation if combined with multivitamins or vitamin B-12. In other words, if the theoretical risks do not reflect real world human activities and the way that people actually obtain essential vitamins from their diet, including supplementation, aren’t these improbable risks really irrelevant to us? On the other hand, these negative reports may stop people from taking essential vitamins in quite reasonable amounts even though they are known to promote human health. Published human clinical science has determined that folic acid can reduce birth defects and has been proven to do so. Clinical science has also found mechanisms by which folic acid can prevent cancers, as well as the theoretical possibility that very high doses given in isolation can stimulate colorectal cancers including prostate cancer. There is stronger evidence that taking B-12 or a multivitamin along with high folic acid actually reduces rates of prostate and colon cancers. For example, in one human clinical trial where food intake, blood and plasma levels of folic acid were considered, Multivitamin users had about 2/3 the risk of subsequent prostate cancer as Non-Multivitamin users; only the independent use of folic acid was considered a risk factor. The report concluded, “…on the whole, the biological and epidemiological evidence supports the potential for folate supplementation to prevent colorectal neoplasia in humans.” (Cole) This shows that single nutrient studies, especially if unpublished and not peer reviewed or subjected to subsequent comments by experts in the field, should not be given overinflated importance when they are merely preliminary studies that may conflict with more relevant published human clinical studies. In the case of such conflicts, the human clinicals should bear more weight and be seen as more convincing, especially those that mimic the full range of variables (nutrients) in the human diet. Folic acid itself is considered non-toxic. Also, “data from in vitro and in vivo studies indicate that folic acid is not genotoxic [damaging to genetic material]”. (UK Food Standards Agency) There have been reports of levels as high as 50,000 micrograms per day given with no signs of toxicity in humans. There are accepted problems associated with levels exceeding 5,000 micrograms a day, which resulted in a far more conservative Upper Limit of 1,000 micrograms daily being set. This effect has been demonstrated in patients suffering from pernicious anemia taken off of their successful medicine (vitamin B-12), which was replaced by 5,000 mcg/day of folic acid. The substitution of one vitamin for another was unsuccessful in treating pernicious anemia, but did mask some symptoms. This test – and a large safety margin - provided the rationale given for the current Upper Limit. But it does not logically imply danger to those who are not severely anemic and who obtain B-12 in adequate amounts. (Oakley) It is very uncommon for people to take folic acid singly in doses of thousands of micrograms daily, but this is the method which test tube and animal studies often use. Overemphasizing unproven cancer risks requires ignoring valid studies showing reductions of cancers by taking folic acid and multivitamins. Needlessly scaring people from taking their vitamins, which have in human clinical trials shown significant improvements in birth defect and cancer rates, is not helpful to our common goal of protecting public health. Neil E. Levin, CCN, DANLA QUOTES & REFERENCES: Dr. Gideon Koren, director of the Motherisk Program at the Hospital for Sick Children in Toronto , note that rates of birth defects such as spina bifida and cancers such as neuroblastoma have plummeted since folic acid supplementation was begun. He believes that the known benefits outweigh theoretical risks. "I think it is very important to remember that the scares about cancer are mostly from animal studies and laboratory studies, not from human experience," he says. "We are still awaiting to see such human experience." http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20090417/folic_acid_090418/20090419?hub=SciTech Health Canada recommends all women of childbearing age take 0.4 mg of folic acid a day, but says taking more than 1 mg a day of folic acid without the advice of a doctor is not recommended. "We continue to encourage all women who could become pregnant to take a daily supplement," the agency says on its website. "We caution against taking more than one multivitamin tablet a day, as excess amounts of certain vitamins can be toxic." http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20090417/folic_acid_090418/20090419?hub=SciTech “All women who could become pregnant should take a multivitamin containing 0.4 mg of Folic Acid every day. To help reduce the risk of NTDs, you should start taking the vitamin supplement at least three months before you get pregnant and continue through the first three months of your pregnancy. Talk to your health professional to find the supplement best for you…If you have had a previous pregnancy affected by an NTD or have a family history of this problem, see your doctor. You may be advised to take a higher dosage of Folic Acid. If you have diabetes, obesity or epilepsy, you may be at higher risk of having a baby with an NTD, and you should see your doctor before planning pregnancy… Do not take more than one daily dose of vitamin supplement as indicated on the product label. Increasing your dose of Folic Acid beyond 1 mg per day without the advice of a doctor is not recommended.” (Public Health Agency of Canada , 2/27/08; http://www.phac-aspc.gc.ca/fa-af/index-eng.php) The NIH’s Office of Dietary Supplement reports on the prevention of cancer with the use of supplemental folic acid as part of a multivitamin: “Over 88,000 women enrolled in the Nurses' Health Study who were free of cancer in 1980 were followed from 1980 through 1994. Researchers found that women ages 55 to 69 years in this study who took multivitamins containing folic acid for more than 15 years had a markedly lower risk of developing colon cancer.” (Giovannucci E, et al. Multivitamin use, folate, and colon cancer in women in the Nurses' Health Study. Ann Intern Med 1998;129:517-24; http://ods.od.nih.gov/factsheets/folate.asp) Cole BF, et al. Folic acid for the prevention of colorectal adenomas: a randomized clinical trial. Polyp Prevention Study Group. JAMA. 2007 Jun 6;297(21):2351-9. PMID: 17551129 Figueiredo JC, et al. Folic acid and risk of prostate cancer: results from a randomized clinical trial. J Natl Cancer Inst. 2009 Mar 18;101(6):432-5. Epub 2009 Mar 10. PMID: 19276452 Folic Acid, CASRN: 59-30-3. NLM TOXNET Hazardous Substances Database accessed online 28 March, 2009. http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@na+folic+acid Lonn E, Yusuf S, Arnold MJ, Sheridan P, Pogue J, Micks M, McQueen MJ, Probstfield J, Fodor G, Held C, Genest J Jr; Heart Outcomes Prevention Evaluation (HOPE) 2 Investigators. N Engl J Med. 2006 Apr 13;354(15):1567-77. Epub 2006 Mar 12. Erratum in: N Engl J Med. 2006 Aug 17;355(7):746. PMID: 16531613 Oakley GP Jr. When will we eliminate folic acid-preventable spina bifida? Epidemiology. 2007 May;18(3):367-8. PMID: 17435446 http://www.food.gov.uk/multimedia/pdfs/evm_folicacid.pdf

The Relative Safety of Natural Products

Some have stated that the dietary supplement industry is largely “unregulated”. My response: This is not really a fair statement considering that recent regulatory efforts – supported by that same industry – have clamped down on the industry’s freedom to operate outside the regulatory system. Drug and dietary supplement regulation are becoming more and more similar, though the safety records of the two types of products are remarkably distinct. The dietary supplement industry is now largely regulated, with more and more regulations closing the gaps. Indeed, the industry strongly supported the law to ban steroid precursors from being sold as dietary supplements, making all such products illegal drugs. And the 2006 passage of a law to require all serious adverse events to be reported to MedWatch within 3 weeks – now in effect - is an appropriate method of monitoring safety and determining problem areas needing increased monitoring or official action; though we should not confuse raw AERs with actual evidence of causes-and-effects. The implementation of the long-delayed current good manufacturing practices (cGMP) regulations (that were actually authorized by the oft-maligned DSHEA law in 1994) now requires all supplement manufacturers to be cGMP compliant over the next two years, but with the largest manufacturers required to follow that standard no later than this coming June (2008). cGMP regulations are forcing manufacturers to have quality controls on raw materials and finished goods throughout the manufacturing process, including identity and safety testing. The FDA already prohibits all adulterated products, and has in fact used its authority to act against known offenders, as noted by the agency itself. 2. There are claims that “the Institute of Medicine and the Food and Drug Administration have found that supplement health claims are largely unsupported”. My response: The FDA clearly regulates supplement label claims and requires manufacturers to submit all label claims and maintain proper documentation. The agency apparently does not review this information unless there is a problem; meanwhile making manufacturers submit such information to it while requiring a contradictory label disclaimer that the FDA has not reviewed the claims. I guess that’s what’s called “plausible deniability”. However, the vast majority of responsible manufacturers are careful to present adequate documentation to the FDA, and the cGMP regulations require well-documented justification of all processes, including the writing of label claims. DSHEA requires preapproval of all new dietary supplement ingredients with an eye to proving safety, though manufacturers are allowed to use existing ingredients if they first submit their new label claims to the agency. All new drugs need pre-approval, as do all new supplement ingredients, but drugs are approved for specific uses (though often used for other unapproved “off label” conditions) while supplements are not allowed to make any disease claims, with very few exceptions for FDA-approved health claims. (http://www.cfsan.fda.gov/~dms/supplmnt.html) 3. Some physicians warn that “supplement use can be associated with death”. My response: Supplements, foods and drugs are all associated with death risks, with supplements statistically being the safest of them all, by far. Some have chosen to focus on a very few cases of dietary supplements possibly linked to deaths, but other readers have mentioned the very large death toll from both properly prescribed drugs and drug errors as a way to counter the thinking that drugs are somehow more tightly regulated, and thus presumably safer, than dietary supplements. I agree. In the annals of our peer-reviewed literature, dietary supplements are rarely responsible for accidental deaths other than by illegal adulteration, making this class of products far safer than less-regulated foods or even more regulated drugs. And, just as in the case of prescription drugs, the FDA does not test for purity and safety. Regulators routinely require industries to have quality controls in place to do such testing themselves, with penalties for non-compliant products that come to the attention of the regulatory agencies. And it is appropriate that regulators focus on the products with the most potential to cause injuries, illnesses and deaths. The routine collection of serious AERs will serve to focus the regulators on problem areas. (For more discussion and literature citations, see #6 below.) 4. There are claims that “We cannot easily know” what’s really in supplements. My response: cGMP manufacturers must test their ingredients, so responsible manufacturers do not allow the use of adulterated ingredients and have means to avoid them. It is likely that the adulterant in this case was deliberately added to ensure a noticeable effect. By definition, an adulterated supplement actually becomes an unlabeled illegal drug, not a dietary supplement. There are already penalties for such adulteration under current regulations, and the FDA has forcefully removed these products from the market. The solution is for cautious consumers to purchase their dietary supplements from responsible brands that have third-party quality certifications, and it is likely that only those individuals seeking foolish shortcuts will be involved with mail order brands of questionable integrity. The vast majority of supplement manufacturers wish to promote natural health and will not risk their companies on such questionable unlawful schemes. 5. Regarding the relative use of pharmaceutical drugs (OTC and prescription) versus dietary supplements, related to a comment that fewer people use supplements and that explains their apparently greater safety compared with drugs: My response: A recent survey reports that, “43 percent of Americans say they take a daily multi-vitamin for cancer protection. 21 percent take some other form of nutritional or dietary supplement.” (http://www.icrsurvey.com/Study.aspx?f=Supplement_survey_release.html) This indicates that a majority of Americans, about 2/3, take dietary supplements. In the case of prescription drugs, about 45% of Americans take a prescription, with the percentage rising sharply with age. (http://www.cdc.gov/nchs/fastats/drugs.htm) And Americans also take non-prescription OTC drugs, with a combined rate of drug use estimated at about 2/3 of all Americans...about the same percentage of the population as uses dietary supplements. So the argument that the use rates are sharply different is not substantiated by the data, meaning that the dramatically lower death and adverse event rates for dietary supplements are indeed a valid testimony to their relative safety versus drugs. 6. Some have commented that just because something is "natural" doesn't mean it's safe. My response: There are no foods or dietary supplements that are unregulated by the FDA, and most natural products are far safer than artificial ones. Most synthetic substances, including drugs, have a far greater risk of side effects and deaths in the clinical literature. Still, we make choices every day and do not stop consuming most foods, drugs or supplements because most have such a tremendous reward-to-risk ratio. We obviously can’t stop eating. And since our diets are known to be deficient in essential nutrients, dietary supplements do have an important role to play in ensuring adequate nutrition. (Nutrition and Your Health: Dietary Guidelines for Americans. USDA. 2005. also Fairfield KM, Fletcher RH. Vitamins for chronic disease prevention in adults: scientific review. JAMA. 2002 Jun 19;287(23):3116-26. Review. Erratum in: JAMA 2002 Oct 9;288(14):1720. PMID: 12069675) It was reported in JAMA that, “Most people do not consume an optimal amount of all vitamins by diet alone. Pending strong evidence of effectiveness from randomized trials, it appears prudent for all adults to take vitamin supplements.” (Fairfield KM, Fletcher RH. Vitamins for Chronic Disease Prevention in Adults: clinical applications. JAMA. 2002;287:3127-3129.) Regarding food safety, a medical journal report concluded that, “We estimate that foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year.” (Mead PS, et al. Food-related illness and death in the United States. Emerg Infect Dis. 1999 Sep-Oct;5(5):607-25. Review. PMID: 10511517). This indicates that eating food is a far riskier activity than taking dietary supplements, since the risk for the 2/3 of food eaters that are also supplement takers is literally orders of magnitude lower than 2/3 of the known risk of eating food (which everyone does). There are few human activities with lower odds of causing death or serious illness than taking dietary supplements. In fact, even lipsticks and cosmetics are typically responsible for more annual accidental deaths than vitamins. Looking at the categories of deaths reported by the American Association of Poison Control Centers from 2002-2004, only 5 accidental deaths were reported linked to dietary supplements, 7 from cosmetics and personal care items, over 600 related to acetaminophen use, 117 related to aspirin use, and 66 from ordinary household cleaners. By far, dietary supplements are probably the safest category of products that we put into our mouths, and are demonstrably getting safer with the new regulations now being implemented. 7. Let’s talk about the real dangers of drugs, which exceed the risks of supplementation by mind-boggling amounts. That is the main reason why drugs are controlled substances. A JAMA report documented the large death toll for properly prescribed drugs: “We estimated that in 1994 overall 2,216,000 (1,721,000-2,711,000) hospitalized patients had serious ADRs and 106,000 (76,000-137,000) had fatal ADRs, making these reactions between the fourth and sixth leading cause of death.” (Lazarou J, Pomeranz BH, Corey PN. Incidence of adverse drug reactions in hospitalized patients: a meta-analysis of prospective studies. JAMA. 1998 Apr 15;279(15):1200-5. PMID: 9555760) Also, the Washington Post reported in its 7/21/06 edition on an Institute of Medicine study released a day earlier on the toll of improperly prescribed drugs: "At least 1.5 million Americans are sickened, injured or killed each year by errors in prescribing, dispensing and taking medications, the influential Institute of Medicine concluded in a major report released yesterday. Mistakes in giving drugs are so prevalent in hospitals that, on average, a patient will be subjected to a medication error each day he or she occupies a hospital bed, the report by a panel of experts said. Following up on its influential 2000 report on medical errors of all kinds, the institute, a branch of the National Academies, undertook the most extensive study ever of medication errors in response to a request made by Congress in 2003 when it passed the Medicare Modernization Act. The report found errors to be not only harmful and widespread, but very costly as well. The extra expense of treating drug-related injuries occurring in hospitals alone was estimated conservatively to be $3.5 billion a year." Prescription drugs were named as one of the largest causes of American deaths, perhaps the second largest, as noted in another report by CDC, also published in JAMA: "IN 2004, POISONING WAS SECOND ONLY to motor-vehicle rashes as a cause of death from unintentional injury in the United States. Nearly all poisoning deaths in the United States are attributed to drugs, and most drug poisonings result from the abuse of prescription and illegal drugs. Previous reports have indicated a substantial increase in unintentional poisoning mortality during the 1980s and 1990s. To further examine this trend, CDC analyzed the most current data from the National Vital Statistics System. This report summarizes the results of that analysis, which determined that poisoning mortality rates in the United States increased each year from 1999 to 2004, rising 62.5% during the 5-year period." (FROM THE CENTERS FOR DISEASE CONTROL AND PREVENTION: Unintentional Poisoning Deaths—United States, 1999-2004. JAMA, March 28, 2007; 297: 1309 - 1311.) As you see, the fuss about dietary supplement safety is in reality a tempest in a teapot, as the risks of eating normal foods and using pharmaceuticals are each far more dangerous, in turn. This is not to minimize the need for strict controls of dietary supplements…but to a large degree, these controls already exist or are currently being implemented. Enforcement has been slowly tightening over the past 15 years. But, looking at these authoritative death and injury statistics, is anyone really surprised that the FDA properly chooses to focus its enforcement actions on products that are proven to be dramatically more dangerous to public health than dietary supplements? Some form of triage is appropriate, given the large number of deaths and injuries from food and drugs. But dietary supplements generally do not significantly contribute to these risks, and therefore do not deserve to be singled out as especially dangerous when they are comparatively very safe. Neil E. Levin, CCN, DANLA