Showing posts with label multivitamin. Show all posts
Showing posts with label multivitamin. Show all posts

Monday, April 20, 2009

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 (Cole) This shows that single nutrient studies, especially if unpublished and not peer reviewed or subjected to subsequent comments by experts in the field, should not be given overinflated importance when they are merely preliminary studies that may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

Monday, February 16, 2009

More nonsense in vitamin research

More nonsense in vitamin research By Neil E. Levin, CCN, DANLA A report in Archives of Internal Medicine, an AMA journal, tells us that “the Women’s Health Initiative study provided convincing evidence that multivitamin use has little or no influence on the risk of common cancers, CVD, or total mortality in postmenopausal women.” [i] A closer look at that report reveals serious shortcomings in its references and logic, leading to questions about its validity. In spite of these defects, this report got extensive press coverage (“Study Says Multivitamins Not Effective”[ii]) to promote the view that multivitamins are worthless. Having read the report and reviewed its references, I have serious questions about its importance, which I can back up by reviewing some of its own references. First of all, on what basis do the authors base their assertion that this report was needed? Actually, on pretty flimsy grounds. They list two references to justify the belief that there is a common “belief that these preparations will prevent chronic diseases, such as cancer and cardiovascular disease (CVD)”, which this report claims to disprove. Their first reference (by the lead author of the current report) actually states that multivitamin nutrients have been effective and accepted in medical practice for the prevention of other conditions: “First, research findings published throughout the past 10–20 y have established that some supplements are very effective for disease prevention and their use has become a part of routine clinical practice [e.g., folic acid during the periconceptional period to reduce the risk of neural tube defects and iron to prevent or treat anemia during pregnancy].” This statement indirectly undermines the underlying argument in the current report that vitamins are worthless against chronic disease. This same reference directly undermines the current report by asserting that most people use multivitamins for general health, not for prevention of serious diseases as is claimed in the current report: “Multivitamins (with or without minerals), the supplements most commonly used by American women, are most likely to be used to maintain general good health.” While this reference mentions that most American women with cancer do take vitamins, it does not pretend to know why they do so. In fact, there is no assertion that people claim to take vitamins to prevent cancer and CVD, and this reference actually gives alternative reasons for that use by patients with those conditions. This reference, like the current study by the same lead author, is dismissive of a law (DSHEA) regulating dietary supplements; and while it decries this law as reducing regulation in some areas, it ignores significant increases in scrutiny that the same law establishes, which I will explore in a subsequent section. To me, for the lead author to twice publish reports focusing on perceived negatives in the law while ignoring its clear positives and other applicable laws that increase federal regulation - implies an agenda that goes beyond scientific inquiry. 1 [iii] [iv] [v] The second reference listed for justifying the report also does not provide the supposed justification. On the contrary, it states, “Generally, participants took multivitamins to feel better… Nearly half of participants reported that they take multivitamins because it is hard to eat a balanced diet.” [vi] An objective observer reading these two references finds that they do not provide the promised justification for testing their own assertion that people take multivitamins to prevent cancer and CVD. Obviously, the current authors have not provided adequate references to support their claimed hypothesis; their own references betray them. Next, the authors claim that dietary supplements are “an industry that is largely unregulated owing to the 1994 Dietary Supplement and Health Education Act [sic].” Two references are listed to defend this assertion. The first is the law itself, which actually creates clear new authority for federal regulation of supplement manufacturing, federal regulation of labels and health claims, federal regulation of new ingredients, making illegal any mislabeled or adulterated products, etc. A fair reading of this law, and of the subsequent regulations that have been written to enforce it, including the mandatory Good Manufacturing Practices currently being implemented, do not support the authors’ claim. [vii] [viii] The second reference given also fails to support its use as a justification for the belief that supplements are largely unregulated: “DS are regulated under food law, but with certain provisions that apply only to DS…Health claims have already been authorized for folic acid and calcium, but not for several others. In 1994, when the Dietary Supplement Health and Education Act (DSHEA) was passed, it expanded and clarified the definition of DS, specified additional requirements for safety and provided for four types of claims of nutritional support…Although S/F [affecting the structure and functions of the body] effects result from both foods and drugs, representation that a product will treat, cure, mitigate or diagnose a disease is reserved for drugs.” [ix] The current report also fails to note industry-supported legislation that now requires serious adverse events to be reported to the FDA’s MedWatch system, which serves as an early warning system for safety problems. [x] We have seen that the first two claims in the current report, namely that people take multivitamins to prevent certain chronic major diseases and that dietary supplements are largely unregulated, are not supported by the report’s own selected references. In other words, there is not any real justification provided to support the need for this particular report. How could the authors cite references that don’t really support their claims? How does this undermine their reasons for doing this study? Another problem is that the current authors rather arbitrarily ignore numerous FDA-approved health claims for dietary supplements in their argument against the use of multivitamins to prevent chronic diseases, including the benefits of calcium for osteoporosis, fiber to prevent coronary heart disease, soy protein to prevent coronary heart disease, plant sterol/stanol esters and risk of coronary heart disease, potassium and the risk of high blood pressure and stroke; claims that already have met the agency’s Significant Scientific Agreement (SSA) standard. [xi] Even more bizarrely, they ignore substantial scientific agreements that were mentioned in the lead author’s own previous publication (which is referenced by the current report) which identified an accepted use of “iron to prevent or treat anemia during pregnancy” and reported “at least 35 randomized-controlled trials have shown that supplemental calcium or calcium–vitamin D combinations increase bone mass and decrease fracture risk in adult females.” 6 Yet the current authors claim: “Despite the widespread use of supplements and the strong consumer beliefs about benefits, convincing scientific data to support efficacy are lacking. With the exception of recommending a folic acid–containing supplement to women of childbearing potential and advising avoidance the use of high-dose beta carotene supplements by smokers, current data are insufficient to formulate public health recommendations for dietary supplement use for otherwise healthy persons.” Also, the FDA has also approved a number of less definitive Qualified Health Claims (QHCs) including calcium and colon/rectal cancer & calcium and recurrent colon/rectal polyps, green tea and cancer, selenium and cancer, antioxidant vitamins & cancer, omega-3 fatty acids & coronary heart disease, B vitamins & vascular disease, phosphatidylserine & cognitive dysfunction and dementia, chromium picolinate & diabetes, calcium & hypertension, pregnancy-induced hypertension and preeclampsia. [xii] The FDA-Approved Health Claims and QHCs are the only disease claims authorized for dietary supplements in the United States, with all others prohibited under the supposedly deregulating DSHEA law. 7 Another reference mischaracterization is the authors’ statement that “One study of more than 1 million Americans reported no association of multivitamin use with total mortality, coronary heart disease mortality, or cancer mortality.” [xiii] If, in fact, one were to read the reference carefully, one might find a more contradictory and less definitive tone: “Because CPS-II collected information on vitamin supplement use only once, in 1982, our measurement of duration of use is imprecise, and we potentially misclassify people who changed their use of multivitamin during the 7-year follow-up. This is an important limitation and may explain why we did not find a reduced risk of colon cancer among women with long duration of multivitamin use, as was found in the Nurses’ Health Study, which had repeat assessments of multivitamin use.” The imprecise nature of this reference must be emphasized. The Cancer Prevention Study II (CPS-II), which relied on a single survey of multivitamin use to classify as users those who claimed to have taken a multivitamin of any strength at least once during the month preceding the survey, was likely to be more and more inaccurate over time, and wherein only about half of the people surveyed claimed to have taken their multivitamin supplement daily during the previous month, is not a strong reference because its weak design does not establish any definitive effects clearly attributed to multivitamins. 13 Contrast this with the admittedly more rigorous Nurses’ Health Study, showing benefits in those taking supplements that were validated by repeatedly assessing whether or not the subjects kept taking their vitamins. [xiv] While the current report has an 8-year follow up period, the Nurses’ Health Study reported significant benefits only after 15 years of multivitamin use, concluding that such “Long-term use of multivitamins may substantially reduce risk for colon cancer.” This is another indication that the current report’s authors have failed to design their study in such a way as to follow previous successes and avoid known shortcomings of previously published studies; surprisingly, not even the ones that they themselves have referenced or written. By looking at only half as much time as was previously shown to be effective, they have produced a far less rigorous and less convincing report. The incubation period of cancers and heart disease is often estimated to be many years. As the National Cancer Institute reports, “Prostate cancer often does not cause symptoms for many years.” [xv] Other sources confirm the lengthy breeding time of cancers. Mouth cancer has a ten-year incubation period. [xvi] Because “the “incubation period between HPV infection and development of invasive cervical cancer is long, prevention of cancer by a vaccination programme will not be obvious for 10 to 20 years.” [xvii] Asbestos dust can cause lung cancer some 10 to 30 years after exposure. [xviii] Cervical cancer “has a long incubation period, between three to 17 years.” [xix] Likewise, “the ‘incubation period’ between exposure to major coronary risk factors and the maximum effects on mortality may be 10 years or more.” [xx] In the current report, “stress multivitamins” [sic] consisting of B-Complex vitamins along with additional factors such as vitamin C or single minerals were classified as multivitamins, though they could lack essential vitamins A, D, and E, as well as most or all of the essential minerals. This is not a normal definition of a multivitamin formula. Stress formulas are normally considered B-Complex supplements that are fortified with one or more additional nutrients to help the body deal with stress, but not as a general all-in-one daily nutritional supplement. People tend to take stress supplements because they feel under stress, not as a general insurance against incomplete diets as multivitamins are taken. 3,6 While the percentage of subjects in this category is small, I question why they would be included as multivitamin users in the current report at all. Perhaps this design flaw betrays a lack of understanding of the topic being investigated, with a strangely unscientific willingness to throw too many doses and formulas in the supposedly controlled mix of variables. In the case of multivitamins, most studies have shown overwhelmingly positive effects; such as one report evidencing reduced infections in nursing homes with vitamins over placebo (73% vs. 43%). Intervention was with a multivitamin containing beta-carotene. Infection-related absenteeism was higher in the placebo group than in the treatment group (57% vs. 21%). Perhaps most importantly, 93% of participants with diabetes mellitus reported an infection versus only 17% of those receiving supplements. [xxi] Interesting, the current report being reviewed also indicates that nonusers had a higher rate of diabetes treatment than multivitamin users; nonusers were treated at a rate of 5.2% while users ranged only from 2.7 to 3.5%. Nonusers also had slightly lower rates (81.4%) of mammograms compared with users (85.7 to 87.2%), which could imply greater rates of undetected breast cancer that may confound comparisons. 1 Another study reported in the Journal of the National Cancer Institute looked at death rates in a population given multivitamins or other nutrients. [xxii] After supplements were given for 5.25 years in the general population trial of 30,000 people, significant reductions in total [relative risk (RR) = 0.91] and cancer (RR = 0.87) mortality were observed in subjects receiving beta-carotene, alpha-tocopherol, and selenium combined. These nutrients are common in multivitamin formulas. The same researchers reported on a subgroup of 3,318 persons with esophageal Dysplasia (a precursor to esophageal cancer) that was given either a multiple vitamin-and-mineral supplement or a placebo for 6 years. In this portion of the trial, a trend towards small reductions in total (RR 0.93) and cancer (RR = 0.96) mortality were observed that did not reach statistical significance. In any case, no increase in cancer rates was noted in the group taking multivitamins; there was actually a possible small benefit in terms of reducing this risk. The participants getting the multivitamin took a daily beta-carotene capsule along with two multivitamin tablets. This was a group of subjects at high risk of getting throat cancer. [xxiii],[xxiv] Another problem with the current study is that these are nutrients and there are several important yet uncontrolled variables preventing meaningful conclusions: * The same nutrients are found in people’s diet, confounding researchers more used to novel drug studies who may be unfamiliar with the need to control additional variables in nutrient study design * The variety of formulations and nutrients included prevent a meaningful comparison by individual or groups of vitamins or minerals, present or absent * The potency of various nutrients taken could vary from absent to very high; there is no dose-dependent data possible in this particular study design that lumped together a wide range of non-homogenous dietary supplements In conclusion, there are many basic omissions and errors in this report’s rationale and design that should have dramatically reduced its importance and avoided a media frenzy over its flimsy conclusions. Unfortunately, nutrient studies often lack adequate critical review and the researchers tend to jump to unsupported conclusions by ignoring important variables. In this case, one problem was the design of a study that was simply too short to show any benefits. Another is the absolute lack of control over potencies and nutrient content. Rather than blaming the vitamins, it was probably pre-existing conditions and supplemental intervention was too little, too late. This report’s authors seem to lack objectivity by referring to an industry that has had numerous new regulatory controls imposed as “unregulated”. They have also chosen to ignore numerous approved health claims for vitamins, as well as evidence of benefits for those suffering from diseases other than cancer and cardiovascular disease. Additionally, they have described unsubstantiated motives for why people take vitamins, designing a study that was too short and included too many uncontrolled variables to be definitive, thus undermining their entire project’s basis and conclusions. Nutrient studies are simply more complex than drug studies and require a much higher level of careful planning to ensure meaningful results and eliminate as many variables as possible. In this case, I fear that the current report failed to do this, in the process generating much heat but little light on the topic.

REFERENCES [i] Neuhouser ML, et al. Multivitamin Use and Risk of Cancer and Cardiovascular Disease in the Women's Health Initiative Cohorts. Arch Intern Med. 169(3), 294-304. FEB 9, 2009 [ii] WSAV-3 TV, NBC affiliate: http://www.wsav.com/sav/news/science/health_med_fit/article/study_says_multivitamins_not_effective/9446/ [iii] Neuhouser ML. Dietary supplement use by American women: challenges in assessing patterns of use, motives and costs. J Nutr. 2003 Jun;133(6):1992S-1996S. Review. PMID: 12771352 [iv] http://www.fda.gov/opacom/laws/pl109462.html [v] http://www.cfsan.fda.gov/~dms/ds-labl.html [vi] Neuhouser ML, Patterson RE, Levy L. Motivations for using vitamin and mineral supplements. J Am Diet Assoc. 1999 Jul;99(7):851-4. PMID: 10405685 [vii] Dietary Supplement and Health Education Act of 1994, Pub L No. 103-417, 103rd Cong (1994). [viii] http://www.cfsan.fda.gov/~dms/supplmnt.html [ix] Hathcock J. Dietary supplements: how they are used and regulated. J Nutr. 2001 Mar;131(3s):1114S-7S. Review. PMID: 11238828 [x] http://www.cfsan.fda.gov/~dms/ds-rept.html [xi] http://www.cfsan.fda.gov/~dms/flg-6c.html [xii] http://www.cfsan.fda.gov/~dms/qhc-sum.html [xiii] Watkins ML, Erickson JD, Thun MJ, Mulinare J, Heath CW Jr. Multivitamin use and mortality in a large prospective study. Am J Epidemiol. 2000 Jul 15;152(2):149-62. PMID: 10909952 [xiv] Giovannucci E, Stampfer MJ, Colditz GA, Hunter DJ, Fuchs C, Rosner BA, Speizer FE, Willett WC. Multivitamin use, folate, and colon cancer in women in the Nurses' Health Study. Ann Intern Med. 1998 Oct 1;129(7):517-24. PMID: 9758570 [xv] National Cancer Institute: http://www.cancer.gov/cancertopics/factsheet/Detection/early-prostate [xvi] Mouth Cancer Foundation: http://www.rdoc.org.uk/chewing_tobacco_risk.html [xvii] Lowndes CM, Gill ON. Cervical cancer, human papillomavirus, and vaccination. BMJ. 2005 Oct 22;331(7522):915-6. No abstract available. Erratum in: BMJ. 2005 Nov 12;331(7525):1120. PMID: 16239668 [xviii] Ministry of Environment of the Republic of Korea: http://eng.me.go.kr/docs/sub2/policy_view.html?topmenu=C&cat=250&class=14 [xix] Indonesian Cancer Foundation: http://www.cvcradio.in/news/blogs/eye-on-indonesia/cervical-cancer-the-number-one-killer-of-indonesian-women [xx] Rose G. Incubation period of coronary heart disease. 1982. Int J Epidemiol. 2005 Apr;34(2):242-4. Epub 2005 Mar 11. PMID: 15764698 [xxi] Liu BA, et al. Effect of multivitamin and mineral supplementation on episodes of infection in nursing home residents: a randomized, placebo-controlled study. J Am Geriatr Soc. 2007 Jan;55(1):35-42. Erratum in: J Am Geriatr Soc. 2007 Mar;55(3):478. PMID: 17233683 [xxii] Blot WI, Li IY, Taylor PR, et al. Nutrition intervention trials in Linxian, China: supplementation with specific vitamin/mineral combinations, cancer incidence, and disease-specific mortality in the general population. J Natl Cancer Inst 1993:8ı:1483-92 [xxiii] Li JY, Taylor PR, et al. Nutrition intervention trials in Linxian, China: multiple vitamin/mineral supplementation, cancer incidence, and disease-specific mortality among adults with esophageal dysplasia. J Natl Cancer Inst. 1993 Sep 15;85(18):1492-8. PMID: 8360932 [xxiv] Blot WI, et al. The Linxian trials: mortality rates by vitamin-mineral intervention group. Am J Clin Nutr. 1995 Dec;62(6 Suppl):1424S-1426S. PMID: 7495242

Tuesday, July 22, 2008

Beta-carotene risks still unproven!

A recent journal article pointed out the widely-reported danger of smokers using beta-carotene, a natural source (provitamin) of vitamin A, as part of their multivitamins. 1 In this meta-analysis (as in common in such analyses) the researchers have neglected to consider pre-existing dietary and serum levels of this nutrient, making their claim to control by placebo inadequate to properly isolate this variable. In fact, this failure to determine the effects of beta-carotene at a dose-dependent plasma level – and by neglecting to measure total beta-carotene intake along with the relevant synergistic antioxidants associated with it, as opposed to simply measuring supplemental intake - raises serious questions about the validity of these results. 2 There is also legitimate scientific debate over the use of trans versus cis forms of this provitamin that may affect the way it is used by our bodies in vivo that dispute whether all forms are equal, which most studies simply do not address (including this meta-analysis). 3 Regarding beta-carotene safety little has been satisfactorily resolved, and the negative studies have been vigorously disputed for these and other reasons. For example, researchers have previously noted in the Journal of the National Cancer Institute that beta-carotene has been shown to not affect the risk of oxidative DNA damage in male smokers, despite its reputation as an antioxidant. But neither did the provitamin A prove to cause oxidative DNA damage. 4 It has become apparent to numerous observers that simply measuring supplementation of beta-carotene is not a good predictor of serum levels or of risk, and that a low level of total antioxidant intake may be a more valid marker in this regard. In fact, the dietary level of several antioxidants has been shown to be an independent predictor of plasma beta-carotene, especially in moderate alcohol drinkers. A recent study reports, "This may explain, at least in part, the inverse relationship observed between plasma beta-carotene and risk of chronic diseases associated to high levels of oxidative stress (i.e., diabetes and CVD), as well as the failure of beta-carotene supplements alone in reducing such risk." 2 As the authors (Tanvetyanon, et al) of this current analysis have themselves noted, the Physicians Health Study compared the effects of taking 50 mg of supplemental beta-carotene (over 83,000 IU) every other day to a placebo in 22,071 US male physicians aged 40-84 and found no adverse health effects over a 12-year study period. 5 Likewise, the Women’s Health Study of 39,876 health professionals found no significant difference on lung cancer rates when looking at the effects of 50 mg of beta-carotene administered on alternate days over 2+ years plus a 4-year follow up period, using forms and dosing similar to the Physician’s Health Study to achieve very high serum levels of beta-carotene. 6 In a third study used in the current meta-analysis, The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group (ATBC), an antioxidant study in Finland was halted early because of a widely reported small increase in cancer rates among male smokers taking beta-carotene that were only possibly linked to that nutrient. 7 Headlines associated this supplement with cancer risk. Despite objections that the study was flawed, beta-carotene use dropped. This study continues to be widely cited and believed, despite the researchers’ own statements that the results were most likely due to chance. A later analysis published in July 2004 took another look at that same Finnish smokers study’s data, but now taking into account total antioxidant intake, which should have cleared away some of the scientific controversy over beta-carotene safety. The smokers’ risk of getting lung cancer was inversely associated with total antioxidants in the diet, with more total antioxidants resulting in fewer cancers. 8 In this study a composite antioxidant index was generated for each of the 27,000 men over 14 years. The calculated amounts of carotenoids, flavonoids, vitamin E, selenium and Vitamin C were compared to actual lung cancer rates, with a clear result: a combination of antioxidants lowered lung cancer risk in male smokers. Properly reviewed, beta-carotene was not the culprit; low antioxidant status was the more relevant factor affecting cancer rates, and supplementation with a single antioxidant supplement simply failed to create enough improvement to avert deaths related to oxidative factors. Perhaps the supplementation with beta-carotene was simply a case of "too little, too late", rather than a root cause of a slightly higher lung cancer rate in those smokers. It is notable that Tanvetyanon et al included the ATBC study but failed to even reference the later Wright et al study that largely refuted the alleged harms of beta-carotene shown in ATBC, which were shown to be more likely due to low levels of total antioxidant intake than to excessive beta-carotene intake. This later review of ATBC should be a cautionary tale concerning the lack of proper controls in nutrient studies, especially as compounded by the use of meta-analysis, and should have alerted the current authors to that all-too-common mistake in nutrient study design. Indeed, another large study has noted that high carotenoid intake, confirmed by measures of plasma, was associated with lower mortality rates among the elderly over a ten year period. 9 This model measured results of consuming both supplements and foods, not solely supplement input, and when combined with plasma levels should therefore be regarded as a far more robust type of science for measuring vitamin effects than a meta-analysis of simply supplementation. As in the long-term Physicians Health Study, there was no observable risk of lung cancer noted in this report. The fourth study used in the current meta-analysis used very high doses of both beta-carotene (30 mg, equal to 50,000 IU) plus 25,000 IU of pre-formed vitamin A. 10 These amounts are extremely high; the Upper Limit for vitamin A is 10,000 IU, though there is no official Upper Limit for beta-carotene because of its historic safety record. The amounts of beta-carotene used in the eye vitamins were high only because the authors selected solely formulas designed for eye health that typically provide more beta-carotene than ordinary multivitamins. This distinction is not clear in their calling such formulas "multivitamins", because that name is typically given to full-spectrum formulas containing a full range of the essential vitamins with minerals, not system-specific formulas like those sold for eye health. Such formulas have proved to be beneficial in maintaining eye health and the combination of antioxidants have been stronger antioxidants than beta-carotene, which is potentially a pro-oxidant at times and could thus be used more safely – and effectively - in combination with other antioxidants. 11 That being said, eye formulas with more milligrams of lutein than beta-carotene are probably better formulated than ones with very high beta-carotene because of their competition for absorption. Most importantly, the authors have not shown why they assume that "multivitamin" use would be associated with the supposed risks of beta-carotene used singly, even if those risks for the solo provitamin are assumed to be true. Nor have they adequately demonstrated the alleged dangers of taking eye formula supplements, or even the danger of lung cancer rates increasing in those taking mixtures of beta-carotene combined with other antioxidant nutrients. In the case of multivitamins most studies have shown overwhelmingly positive effects, such as one report evidencing reduced infections in nursing homes with vitamins over placebo (73% vs. 43%). Intervention was with a multivitamin containing beta-carotene. Infection-related absenteeism was higher in the placebo group than in the treatment group (57% vs. 21%). Perhaps most importantly, 93% of participants with diabetes mellitus reported an infection versus only 17% of those receiving supplements. 12 These huge reductions in potentially serious infections among our elderly citizens should be measured against the relatively slight and mostly theoretical risk of increased lung cancer rates associated with beta-carotene supplementation. A study reported in the Journal of the National Cancer Institute looked at death rates in a population given multivitamins or other nutrients. 13 After supplements were given for 5.25 years in the general population trial of 30,000 people, significant reductions in total [relative risk (RR) = 0.91] and cancer (RR = 0.87) mortality were observed in subjects receiving beta-carotene, alpha-tocopherol, and selenium combined. The same researchers reported on a subgroup of 3,318 persons with esophageal Dysplasia (a precursor to esophageal cancer) that was given either a multiple vitamin-and-mineral supplement or a placebo for 6 years. In this portion of the trial, small reductions in total (RR 0.93) and cancer (RR = 0.96) mortality were observed but were not significant. In any case, no increase in cancer rates was noted in the group taking multivitamins; there was actually a possible small benefit in terms of reducing this risk. The participants getting the multivitamin took a daily beta-carotene capsule along with two multivitamin tablets. This was a group of subjects at high risk of getting throat cancer. 14-15 It is a leap of faith to assume that a single nutrient would have identical effects to a combination of nutrients without substantial supporting evidence, which is still lacking; confounded by conflicting evidence and multiplying variables in meta-analyses. Since nutrients are both synergistic and present in the diet, it is important to factor those known variables into a proper study design. All too often, researchers do not consider this fundamental difference between drug and nutrient research and unwittingly introduce extra variables that undermine their conclusions. 16

This current meta-analysis of 4 studies - only one of which unquestionably shows a slight increase in lung cancer risk but does not actually measure isolated beta-carotene risk; two others are well-designed and robust studies looking at serum levels of those taking a high dose of beta-carotene but show no increased risk in lung cancer rates, and the fourth has been largely shown to be moot by a later and more complete re-analysis of the data - does not support the hypothesis that beta-carotene increases rates of lung cancer and that multivitamins are therefore dangerous. Thus, there is no sound basis in the current review for suggesting that warning labels may be needed for multivitamins or eye health supplements containing beta-carotene along with other nutrients that have been shown in well-designed studies to help protect the eyesight – and independence - of our aging population. REFERENCES:

  1. Tanvetyanon T, Bepler G. Beta-carotene in multivitamins and the possible risk of lung cancer among smokers versus former smokers: a meta-analysis and evaluation of national brands. Cancer. 2008 Jul 1;113(1):150-7. PMID: 18429004
  2. Valtueña S, et al. The total antioxidant capacity of the diet is an independent predictor of plasma beta-carotene. Eur J Clin Nutr. 2007 Jan;61(1):69-76. Epub 2006 Jul 12. PMID: 16835597 [Supported by the European Community IST-2001–33204 'Healthy Market', the Italian Ministry of University and Research COFIN 2001 and the National Research Council CU01.00923.CT26 research projects.]
  3. Andreas Schieber, Reinhold Carle. Occurrence of carotenoid cis-isomers in food: Technological, analytical, and nutritional implications. Trends in Food Science & Technology, Volume 16, Issue 9, September 2005, Pages 416-422
  4. van Poppel G, Poulsen H, Loft S, Verhagen H. No influence of beta carotene on oxidative DNA damage in male smokers. J Natl Cancer Inst. 1995 Feb 15;87(4):310-1. PMID: 7707423
  5. Hennekens CH, Buring JE, Manson JE, et al. Lack of effect of long-term supplementation with beta carotene on the incidence of malignant neoplasms and cardiovascular disease. N Engl J Med. 1996 May 2;334(18):1145-9. PMID: 8602179
  6. Lee IM, Cook NR, Manson JE, Buring JE, Hennekens CH. Beta-carotene supplementation and incidence of cancer and cardiovascular disease: the Women's Health Study. J Natl Cancer Inst. 1999 Dec 15;91(24):2102-6. PMID: 10601381
  7. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. N Engl J Med. 1994 Apr 14;330(15):1029-35. PMID: 8127329
  8. Wright ME, et al. Development of a comprehensive dietary antioxidant index and application to lung cancer risk in a cohort of male smokers. Am J Epidemiol. 2004 Jul 1;160(1):68-76. PMID: 15229119
  9. Buijsse B, et al. Plasma carotene and alpha-tocopherol in relation to 10-y all-cause and cause-specific mortality in European elderly: the Survey in Europe on Nutrition and the Elderly, a Concerted Action (SENECA). Am J Clin Nutr. 2005 Oct;82(4):879-86. PMID: 16210720
  10. Omenn GS, Goodman GE, Thornquist MD, et al. Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med. 1996;334:1150–1155.
  11. Bartlett H, Eperjesi F. Age-related macular degeneration and nutritional supplementation: a review of randomised controlled trials. Ophthalmic Physiol Opt. 2003 Sep;23(5):383-99. Review. PMID: 12950886
  12. Liu BA, et al. Effect of multivitamin and mineral supplementation on episodes of infection in nursing home residents: a randomized, placebo-controlled study. J Am Geriatr Soc. 2007 Jan;55(1):35-42. Erratum in: J Am Geriatr Soc. 2007 Mar;55(3):478. PMID: 17233683
  13. Blot WI, Li IY, Taylor PR, et al. Nutrition intervention trials in Linxian, China: supplementation with specific vitamin/mineral combinations, cancer incidence, and disease-specific mortality in the general population. J Natl Cancer Inst 1993:8ı:1483-92
  14. Li JY, Taylor PR, et al. Nutrition intervention trials in Linxian, China: multiple vitamin/mineral supplementation, cancer incidence, and disease-specific mortality among adults with esophageal dysplasia. J Natl Cancer Inst. 1993 Sep 15;85(18):1492-8. PMID: 8360932
  15. Blot WI, et al. The Linxian trials: mortality rates by vitamin-mineral intervention group. Am J Clin Nutr. 1995 Dec;62(6 Suppl):1424S-1426S. PMID: 7495242
  16. Levin, N. Land of Confusion: How Poor Science and Misleading Media Coverage Create Public Confusion About How Dietary Supplements Affect Health. J App Nutr, Vol 55, No. 1, 2005 8-15

Wednesday, July 09, 2008

Memory and Age

Memory and Age By Neil E. Levin, CCN, DANLA The most important things for an older person to consider in protecting against minor memory loss – often attributed to “aging” – include: · Maintain at least a nominal physical activity level to keep circulation and body functions at optimal levels. · Take a good multivitamin to assure minimal levels of essential nutrients. Too many elders fail to eat properly or to get adequate levels of B vitamins and other key nutrients associated with proper cognitive function. Also, the elderly don’t absorb nutrients from food as efficiently, making supplementation even more important. · Don’t forget to eat meals. Often, single, divorced or widowed seniors fail to eat regular meals on schedule. This creates nutrient deficiencies that complicate their ability to maintain physical and mental health. · Don’t overeat on processed, high fat, high sodium foods such as fast foods to “compensate” for poor eating habits. · Take foods and supplements that are rich in antioxidants. Oxidative damage is clearly associated with many of the conditions that affect mental, as well as physical, capabilities in older people. This includes negative changes to the brain itself; and also the nervous system, the eyes and joints. · Use vitamin D, which may be in your multivitamin or calcium supplement, to compensate for the lack of direct sunlight on skin. This essential vitamin also helps with immunity, cardiovascular health and bone health. · If your dietary habits are reasonably good and you still want some more natural aids for brain and memory function, consider a brain nutrient formula. Of course, college age is a time when many students want to use brain nutrients to maximize their learning and recall, especially for tests. Many adults then coast through adulthood until they reach their 40’s or 50’s and start to get a little forgetful. By then, they should already be examining their diet, lifestyle and stress levels to consider whether they may need additional nutritional support for their mental functions. If they wait until things get bad - in their 60’s, 70’s or later - it may be too late to preserve their memories and mental acuity. Basic brain nutrients are multivitamins, lecithin and fish oil. Antioxidants will protect the brain’s structures and functions throughout adulthood. Magnesium, an essential mineral that is deficient in 90% of Americans, helps to reduce toxic effects of chemicals on neurons; as do antioxidants such as vitamin E, tocotrienols, and vitamin C. People will usually hint at the need, or ask about Ginkgo or look at the section. We’re not the family, friends or work colleagues that people try to hide symptoms from…after all; we are the ones that perfect strangers often disclose their bowel habits and other normally hidden quirks to. Speaking in user-friendly but technical structure-function language will often make the discussion less personal and more scientific, removing much of the emotional content of the health issue. Phosphatidyl Serine is a phospolipid compound derived from soy lecithin that plays an essential role in cell membrane composition and intercellular communication. Phosphatidyl Serine is a major structural component of neural membranes where it assists in the conduction of electrical impulses and facilitates the activity of neurotransmitters involved in learning, memory and mood. These properties make Phosphatidyl Serine formulas ideal basic supplements for the support of cognitive function. There is enough evidence of the safety and efficacy of PS for the FDA to have issued a qualified health claim for it. DMAE is known primarily as a precursor to choline and acetylcholine (chemicals in the brain responsible for nerve transmissions and cognitive function), and has been used most predominantly to improve memory and focus while stimulating neural activity. Many researchers believe that it may serve an anti-aging function by increasing the body’s capacity to produce acetylcholine – a deficiency commonly associated with memory loss. Scientific research has demonstrated that Ginkgo Biloba Extract has antioxidant activity in in vitro studies and thus may aid in maintaining healthy brain and memory function. The insulating myelin sheaths that protect the brain, spine and thousands of miles of nerves in the human body are almost two-thirds Lecithin. Lecithin is composed of many different components, including Choline, Inositol, Linoleic Acid, Phosphatidyl serine, fatty acids and triglycerides. These valuable constituents of Lecithin are vital for the proper functioning of many metabolic processes. And let’s not forget the benefit of DHA and fish oil. Fish oils are typically molecularly distilled and tested to be free of screened for the absence of potentially harmful levels of contaminants (i.e. mercury, heavy metals, PCB's, dioxins, and other contaminants). DHA is utilized in forming the brain and nerves. And last but not least, antioxidants and magnesium are very helpful in protecting brain structures and may be useful in preventing some of the feared declines associated with aging brains. For example, vitamin C actually pumps glutamates out of neurons.

Friday, March 09, 2007

Multiple Vitamins - Waste or Wise?

Multiple Vitamins - Waste or Wise? The information in this presentation is for educational purposes only. It is not intended to serve as a replacement for the advice of a medical professional. Amid the current confusion about whether or not to take multivitamins, here are some facts you should consider: There are widespread nutrient deficiencies in America: According to dietary data from the National Health and Nutrition Examination Survey 1999-2000, ninety percent or more of the adults studied had their usual intakes below the current Estimated Average Requirement. 9-11 A report published in the medical journal JAMA made this strong statement: “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.” 2 There is strong evidence that multivitamins may improve immune functions in adults: A so-called “gold standard” randomized, double-blind, placebo-controlled trial looked at adults age 45+ during a one-year study, with results of diabetic and non-diabetic subjects reported separately. 1 73% of those receiving the placebo reported getting infections over the year versus 43% of those taking multivitamins, a 30% difference. Infection-related absenteeism was also found to be much higher in the placebo group (57%) than in the treatment group (21%). But the most striking results were found among the diabetic subjects. A whopping 93% of diabetics receiving the placebo reported getting infections versus only 17% of those taking vitamins, an amazing 76% difference! In other words, the diabetics that did not take multivitamins were over five times as likely to report infections as those in the group that did take the vitamins. Multivitamins reduce birth defects: A meta-analysis of published studies reviewing women’s use of prenatal multivitamins was published by the Journal of Obstetrics and Gynaecology of Canada (JOGC). Researchers found that taking prenatal multivitamins may reduce the risk of a wide range of serious birth defects, including: cardiovascular and limb defects, cleft palate and oral cleft, congenital hydrocephalus, and urinary tract anomalies. Their conclusion was that, “Maternal consumption of folic acid-containing prenatal multivitamins is associated with decreased risk for several congenital anomalies, not only neural tube defects. These data have major public health implications, because until now fortification of only folic acid has been encouraged. This approach should be reconsidered.” 3 The data indicated that the possible benefits to infants of their mothers taking prenatal multivitamins went far beyond the well-known prevention of neural tube defects in the children. That known benefit has already led to widespread fortification of folic acid in processed foods, especially refined flour. Multivitamins protect pregnant women and their fetuses: Another possible benefit of multivitamin use is to prevent potentially fatal complications in pregnant women. This finding was reported by researchers at the University of Pittsburgh: “Women who are considering becoming pregnant may significantly reduce their risk of developing a common life-threatening complication called pre-eclampsia by taking a multivitamin supplement regularly three months before conception and during the first trimester of pregnancy.” 8 Multivitamins reduce infertility: Harvard scientists found that women who took multivitamins at least six times a week were over 40% less likely to have fertility problems linked to ovulation than other women. Dr Jorge Chavarro, from the Harvard School of Public Health, presented his findings to delegates at the American Society for Reproductive Medicine conference in New Orleans in October, 2006. 4 Multivitamins and chronic conditions: Another scientific review published in JAMA noted that, “Although the clinical syndromes of vitamin deficiencies are unusual in Western societies, suboptimal vitamin status is not. Because suboptimal vitamin status is associated with many chronic diseases, including cardiovascular disease, cancer, and osteoporosis, it is important for physicians to identify patients with poor nutrition or other reasons for increased vitamin needs. The science of vitamin supplementation for chronic disease prevention is not well developed, and much of the evidence comes from observational studies.” 5 The report concluded, “Some groups of patients are at higher risk for vitamin deficiency and suboptimal vitamin status. Many physicians may be unaware of common food sources of vitamins or unsure which vitamins they should recommend for their patients. Vitamin excess is possible with supplementation, particularly for fat-soluble vitamins. Inadequate intake of several vitamins has been linked to chronic diseases, including coronary heart disease, cancer, and osteoporosis.” Multivitamins may reduce childhood tumors: In a case-control study of brain tumors and the mothers’ use of vitamin and mineral supplements early in pregnancy, the researchers confirmed earlier research indicating that mothers taking multivitamins had a reduced risk of their child developing brain tumors. “The results of the study add to the evidence of a protective role for multivitamins, suggest a possible role for micronutrients early in pregnancy...” 6 Vitamin-Mineral Deficiencies are Theoretically Linked to Increased Cancer Risks: Researchers writing in the scientific journal Nature Reviews Cancer have stated, “Diet is estimated to contribute to about one-third of preventable cancers -- about the same amount as smoking. Inadequate intake of essential vitamins and minerals might explain the epidemiological findings that people who eat only small amounts of fruits and vegetables have an increased risk of developing cancer. Recent experimental evidence indicates that vitamin and mineral deficiencies can lead to DNA damage. Optimizing vitamin and mineral intake by encouraging dietary change, multivitamin and mineral supplements, and fortifying foods might therefore prevent cancer and other chronic diseases.” 7 There is a wide range of published research on multivitamins and I have presented only a sampling to you today. I hope that this information intrigues you as to the potential benefits of the vitamins and minerals found in multivitamins, and the fact that some respected health authorities advocate that most Americans take a good multivitamin. Copyright 2007 Neil E. Levin REFERENCES: Barringer TA, et al. Effect of a multivitamin and mineral supplement on infection and quality of life. A randomized, double-blind, placebo-controlled trial. Ann Intern Med. 2003 Mar 4;138(5):365-71. PMID: 12614088 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 Goh YI, et al. Prenatal multivitamin supplementation and rates of congenital anomalies: a meta-analysis. J Obstet Gynaecol Can. 2006 Aug;28(8):680-9. PMID: 17022907 Chavarro, J. (Harvard School of Public Health) American Society for Reproductive Medicine conference. New Orleans, LA. October 2006. 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 Bunin GR, et al. Maternal supplement, micronutrient, and cured meat intake during pregnancy and risk of medulloblastoma during childhood: a children's oncology group study. Cancer Epidemiol Biomarkers Prev. 2006 Sep;15(9):1660-7. PMID: 16985028 Ames BN, Wakimoto P. Are vitamin and mineral deficiencies a major cancer risk? Nat Rev Cancer. 2002 Sep;2(9):694-704. Bodnar LM, et al. Periconceptional multivitamin use reduces the risk of preeclampsia. Am J Epidemiol. 2006 Sep 1;164(5):470-7. Epub 2006 Jun 13. PMID: 16772374 Dial S, Eitenmiller RR. 1995. Tocopherols and tocotrienols in key foods in the U.S. diet. In: Ong ASH, Niki E, Packer L, eds. Nutrition, Lipids, Health, and Disease. Champaign, IL: AOCS Press. Pp. 327–342. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids (2000). Institute of Medicine, NIH Ahuja JK, et al. Current status of vitamin E nutriture. Ann N Y Acad Sci. 2004 Dec;1031:387-90. PMID: 15753177