On supplements…

THE QUICK TAKE:  Unless you have a demonstrated deficiency, or a high degree of suspicion for a deficiency, there is little evidence of benefit for the regular use of supplements for otherwise healthy people, and surprisingly, there has been some evidence of harm.  Nutrients best come from whole food, and in their original form, given that what the human body is best adapted to absorb.  Save your money, and spend it on healthy whole foods instead, especially locally grown and organic when possible.

THE ONE MINUTE+ VERSION:

Although this is an estimated 25-billion dollar per year industry in the USA alone, the evidence for the use of supplements for otherwise healthy people, the “worried well”, remains murky, and recent reviews have not helped to clarify the value of taking them.  Even calcium, for decades one of the most recommended supplements for women, despite only minimal demonstration of benefit for some post menopausal fractures in an older cohort study in 1997 and 2002, has more recently been reported as having no benefit in one review, and possible increased risk of fractures was reported in a meta-analysis of prospective cohort studies and randomized control trials. And now a 12 year prospective study published in 2013 in JAMA has linked supplemental (but not dietary) calcium intake with increased risk of cardiovascular disease.  For a comprehensive review on the health effects of calcium, in food and in supplements, see this recent report by the National Institutes of Health, Office of Dietary Supplements.

There are many beliefs that people hold that seem to justify the use of various supplements, yet the science is lagging behind.  Check out a recent post by food author, nutrition expert and blogger Marion Nestle, who recognizes a difference in what has been scientifically demonstrated versus what people believe is true.

The perceived need for supplements has lead to their use as an insurance policy for complete nutrition, for several reasons:

  • Many people’s diets do not always follow dietary recommendations–since avoidance of fruits and/or vegetables is common, eating habits may lack many essential nutrients.
  • Foods grown on depleted soils may lack essential nutrients, an uncertainty worsened by our increasing ignorance of where foods originate. The trend of buying organic foods and buying locally are reflections of this concern.
  • Pollution, pesticides, smoking, illness, high work or exercise loads, and stressful living conditions may increase nutrient requirements, and particularly, anti-oxidative needs.
  • Cooking and various other forms of food processing decreases or destroys essential nutrients; conversely, some cooking techniques may add nutrients, such as iron from cookware, or toxins from high heat exposures.
  • Nutrient-related physiological functions and nutrient absorption decline with age.
  • Many patients with poor health or fatigue most often assume they are lacking a nutrient (although there are many possible causes), and therefore pursue supplementation to improve their condition.

A science-based approach considers:

  • Food in reasonable variety is sufficient to meet nutrient needs.
  • Foods provide a wide variety of nutrients that work in synergy (and in better physiological balance) and other valuable substances (such as phytochemicals) not present in supplements.  Humans are best adapted to consuming whole foods, and recognized naturally occurring nutrients.
  • The concentrated nature of supplements may adversely affect absorption of other competing nutrients and the balance of healthy bacterial flora.  They also do not usually come with necessary enzymes, buffers, and synergistic cofactors, as with natural food.
  • People who take supplements are better educated, more physically active, and wealthier: they are healthier whether or not they take supplements, which confounds the perception that taking supplements make people healthier.
  • Studies to date have failed to demonstrate the value of a wide variety of supplements for otherwise healthy people, and some have found increased risks.

Marion Nestle has had several comments on the pros and cons of supplements in recent years, on vitamin, calcium and osteoporosis here, the claims of the supplement industry here, on the minimal health benefits for cancer here, and more bad news on supplements here.

Consider the Iowa Women’s Health study, which associates increased mortality with several supplements, especially iron.  Or a long term followup of the SELECT trial, that confirmed that there was a significantly increased risk of prostate cancer with Vitamin E supplementation.  A 2009 review of vitamin supplementation and risk of various cancers is overall disappointing.  A 2007 meta-analysis in JAMA suggested that some supplements, such as vitamin A, E, and beta-carotene, posed increased risks. Yet an older observational study on vitamin A and osteoporosis suggested that both low and high serum levels posed a risk of hip fracture.

Most recently, The USPSTF concluded that “the current evidence is insufficient to assess the balance of the benefits and harms of combined vitamin D and calcium supplementation for the primary prevention of fractures in premenopausal women or in men.”   See Figure.

Yet, there are reviews that appear to justify increasing risks of various nutrient deficiencies.  Vitamin C intakes may be inadequate in those who avoid fruits and vegetables, who smoke, or who are ill, as outlined by this review.  There is evidence that low vitamin K intakes associate with increasing risk of osteoporotic fractures, and supplementation strongly associates with a decreased risk. Increased vitamin K2 has also been associated with decreased risk of coronary calcification in post-menopausal women in this observational study.

So, despite many years of supplementation by millions of people, the evidence for any value of supplementation remains limited, weak or contradictory, and in some cases suggest increased risk.  Consider the statements in the introduction to a 2009 review on the concept “food synergy”:

“…. ‘‘thinking food first’’ results in more effective nutrition research and policy. The concept of food synergy provides the necessary theoretical underpinning. The evidence for health benefit appears stronger when put together in a synergistic dietary pattern than for individual foods or food constituents.  A review of dietary supplementation suggests that although supplements may be beneficial in states of insufficiency, the safe middle ground for consumption likely is food. Also, food provides a buffer during absorption. Constituents delivered by foods taken directly from their biological environment may have different effects from those formulated through technologic processing, but either way health benefits are likely to be determined by the total diet. The concept of food synergy is based on the proposition that the interrelations between constituents in foods are significant.”

“A person or animal eating a diet consisting solely of purified nutrients in their Dietary Reference Intake amounts, without benefit of the coordination inherent in food, may not thrive and probably would not have optimal health. This review argues for the primacy of food over supplements in meeting nutritional requirements of the population”.

So, unless you have a demonstrated deficiency of a specific vitamin or mineral, or a reasoned possibility of deficiency, save the money you spend on supplements, and redirect to a variety of healthy, whole foods purchases.  And if you do need a supplement, the most commonly justified are iron, vitamin B12, vitamin D, omega-3 fatty acids, vitamin K2, and magnesium.  Just make sure that you are getting them in the form that is a close to biological as possible.  For example, folate does not appear in nature, but tetrahydrofolate does.  For another review  on wise supplementation, go here.  And there is a healthier way to get stronger bones: exercise!  Check out what the National Osteoporosis Foundation recommends here.

 

 

References:

Calcium intake and hip fracture risk in men and women: a meta-analysis of prospective cohort studies and randomized controlled trialsHeike A Bischoff-Ferrari, Bess Dawson-Hughes, John A Baron, Peter Burckhardt, Ruifeng Li, Donna Spiegelman, Bonny Specker, John E Orav, John B Wong, Hannes B Staehelin, Eilis O’Reilly,Douglas P Kiel, and Walter C Willett. Am J Clin Nutr  December 2007 vol. 86 no. 6 pp.1780-1790.

Calcium Intakes and Femoral and Lumbar Bone Density of Elderly U.S. Men and Women: National Health and Nutrition Examination Survey 2005–2006 Analysis. J. J. B. Anderson, K. J. Roggenkamp and C. M. Suchindran. J Clin Endocrinol Metab. 2012 Dec;97(12):4531-9. doi: 10.1210/jc.2012-1407. Epub 2012 Oct 15.   See also this.

Associations of dietary calcium intake and calcium supplementation with myocardial infarction and stroke risk and overall cardiovascular mortality in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition studyHeart. 2012 Jun;98(12):920-5. doi: 10.1136/heartjnl-2011-301345.

Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis.   BMJ. 2010 Jul 29;341:c3691. doi: 10.1136/bmj.c3691. Bolland MJAvenell ABaron JAGrey AMacLennan GSGamble GDReid IR.

Dietary and Supplemental Calcium Intake and Cardiovascular Disease MortalityThe National Institutes of Health–AARP Diet and Health StudyQian Xiao, PhD; Rachel A. Murphy, PhD; Denise K. Houston, PhD; Tamara B. Harris, MD; Wong-Ho Chow, PhD; Yikyung Park, ScD  JAMA Intern Med. 2013 Feb 4:1-8. doi: 10.1001/jamainternmed.2013.3283.

Calcium supplements: bad for the heart? Ian R Reid,  Mark J Bolland. Heart. 2012 Jun;98(12):895-6. doi: 10.1136/heartjnl-2012-301904.

Diet Supplement Fact Sheet: Calcium.  Office of Dietary Supplements, National Institutes of Health, USA Office of Disease Prevention.  Reviewed: March 14, 2013

The risk of kidney stone formation: the form of calcium matters. Favus MJ.  Am J Clin Nutr. 2011 Jul;94(1):5-6. doi: 10.3945/ajcn.111.018481. Epub 2011 Jun 1.

Long term calcium intake and rates of all cause and cardiovascular mortality: community based prospectivelongitudinal cohort study. Michaëlsson K, Melhus H, Warensjö Lemming E, Wolk A, Byberg L. BMJ. 2013 Feb 12;346:f228. doi: 10.1136/bmj.f228.

Dietary and Supplemental Calcium Intake and Cardiovascular Disease Mortality: The National Institutes of Health-AARP Diet and Health Study. Xiao Q, Murphy RA, Houston DK, Harris TB, Chow WH, Park Y. JAMA Intern Med. 2013 Feb 4:1-8. doi: 10.1001/jamainternmed.2013.3283.  See also this.

Effects of widely used drugs on micronutrients: A story rarely told. Samaras D, Samaras N, Lang PO, Genton L, Frangos E, Pichard C.  Nutrition. 2013 Apr;29(4):605-10. doi: 10.1016/j.nut.2012.11.011.

Calcium intake and fracture risk: results from the study of osteoporotic fractures. Cumming RG, Cummings SR, Nevitt MC, Scott J, Ensrud KE, Vogt TM, Fox K. Am J Epidemiol. 1997 May 15;145(10):926-34.     http://aje.oxfordjournals.org/content/145/10/926.long

Meta-analyses of therapies for postmenopausal osteoporosis. VII. Meta-analysis of calcium supplementation for the prevention of postmenopausal osteoporosis.  Shea B, Wells G, Cranney A, Zytaruk N, Robinson V, Griffith L, Ortiz Z, Peterson J, Adachi J, Tugwell P, Guyatt G; Osteoporosis Methodology Group and The Osteoporosis Research Advisory Group.  Endocr Rev. 2002 Aug;23(4):552-9.

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