Are the Nutrients You Consume Bioavailable?
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How to get the most out of your diet and supplements
The body’s physiology is intricate and complex. Even when we eat a healthy diet, we may not always absorb or utilize all of the nutrients our body needs. This is why scientists who formulate nutrient supplements are obsessed with bioavailability, defined as the rate and extent to which the active ingredient is absorbed and becomes available at its site of action.,
The efficiency with which the body absorbs nutrients, either from the diet or supplements, is critical when it comes to health effects. If only 10% of a particular nutrient is bioavailable, for example, we may be missing many of the benefits we hope to achieve. If we understand the factors that impact nutrient bioavailability, we can more intelligently select supplements to meet our needs.
What determines nutrient bioavailability?
Chemical, biological, and physiological factors all influence nutrient bioavailability. These factors include the chemical form of the nutrient, the level of gastric acidity, gut motility, the composition of the microbiota, and the presence of enhancers, inhibitors, or competitors of gut absorption. Bioavailability is also influenced by hormones, chronic and acute infections, gut inflammation, stress, genetic polymorphisms, disease processes, and a wide variety of medications.
The bioavailability of micronutrients, i.e. vitamins, minerals, and bioactive phytochemicals (flavonoids, polyphenols, and carotenoids), can vary widely depending on conditions.
Macronutrients – carbohydrates, proteins, and fats – are usually highly bioavailable, with more than 90% of the amount ingested being absorbed and utilized in the human body. By contrast, the bioavailability of micronutrients, i.e. vitamins, minerals, and bioactive phytochemicals (flavonoids, polyphenols, and carotenoids), can vary widely depending on conditions. Let’s examine some of these effects for specific nutrients.
Some vitamers are more bioavailable than others
Vitamins often exist in different chemical forms (vitamers), some of which are more bioavailable than others. An example of this can be seen for vitamin D, a deficiency of which is becoming a worldwide health problem. Vitamin D supplementation is the best approach to maintain adequacy, but the form of vitamin D used for supplementation matters. If you examine supplement labels you may find one of two forms of vitamin D: ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3). So which form is best? Numerous studies have shown that vitamin D3 is far more effective than vitamin D2 at raising circulating levels of vitamin D and improving vitamin D status.,,
Vitamin E is also not a single entity. The vitamin E family includes tocopherols (α-, β-, δ-, and γ-tocopherol) along with tocotrienols (α-, β-, δ-, and γ-tocotrienol) which activate distinct cellular pathways.,,, While α-tocopherol has long been regarded as the dominant form of vitamin E, the tocotrienols recently have been shown to possess superior antioxidant and anti-inflammatory effects, especially with respect to maintaining healthy blood cholesterol levels and supporting bone and heart health.,, This argues for supplementation with a mixture of tocopherols and tocotrienols as compared with α-tocopherol alone.
Low levels of vitamin K2 have been implicated in chronic age-related diseases such as cardiovascular diseases, osteoporosis and osteoarthritis.
Vitamin K, too, comes in different forms. Although vitamin K1 (phylloquinone) and vitamin K2 (menaquinone, which exists in several forms) have historically been grouped into the same category, these molecules have different absorption characteristics and tissue distributions. Vitamin K1 is preferentially retained in the liver to assist in carboxylation (activation) of blood clotting factors. In contrast, vitamin K2, in particular long-chain derivatives such as menaquinone-7 (MK-7), are redistributed to the circulation and are available for other tissues.,,, Low levels of vitamin K2 have been implicated in chronic age-related diseases such as cardiovascular diseases, osteoporosis and osteoarthritis, and vitamin K2 supplementation may reduce these risks.,,,
Nutraceutical formulations affect bioavailability
Curcumin is poorly absorbed unless it is formulated in such a way as to disperse the lipophilic components.
Many nutraceuticals have intrinsically low bioavailability, unless they are combined with other substances that facilitate absorption of the active ingredient(s). This is particularly true for fat-soluble (lipophilic) substances, including polyphenols. Curcumin is a good example: it is a polyphenol derived from the dietary spice turmeric, which has many promising health-promoting effects including anti-inflammatory and antioxidant properties., But curcumin is poorly absorbed unless it is formulated in such a way as to disperse the lipophilic components.,,,
To address this problem, a variety of curcumin formulations have been developed and evaluated., Research suggests that the best bioavailability can be obtained with a molecular process that enhances the water dispersion of the fat-soluble ingredients. Such a formulation was shown to yield six times higher absorption than the commonly used curcumin phytosome (a complex of curcumin with phospholipids), and 46 times greater absorption than unformulated curcumin, resulting in elevated serum concentrations that persisted over 12 hours.
Physiological influences on nutrient digestion
Due to the risk for nutrient insufficiency, individuals with digestive difficulties may benefit from multivitamin and mineral supplementation. In addition, supplemental digestive enzymes, bile acids, and probiotics, may facilitate digestion and improve nutrient status.
Many factors that impact digestion also affect bioavailability., For example, nutrient bioavailability may be compromised in individuals with pancreatic insufficiency, inflammatory bowel disease (IBD; including Crohn’s disease or ulcerative colitis), irritable bowel syndrome (IBS), celiac disease, cystic fibrosis, and gastrointestinal surgeries, including bariatric surgery., Micronutrient deficiencies occur in more than half of patients with IBD. Deficiencies of iron, folic acid, selenium, zinc, and vitamins D, K, B1, B6, and B12 are particularly common.,,,
Pancreatic insufficiency (PI) reduces the absorption of fat-soluble vitamins, namely vitamins A, D, E and K. The absorption of these and other lipid-soluble nutrients requires the production of lipase by the pancreas, so low levels of pancreatic enzymes are associated with nutrient deficiencies.,,, The most well-known cause of PI is chronic pancreatitis, but PI can also occur in individuals with cystic fibrosis, weight loss surgery, IBS, diabetes or metabolic syndrome,, celiac disease,, small intestinal bacterial overgrowth, or IBD.,,
In fact, PI may be more common than previously thought, even in individuals without a defined gastrointestinal condition.,, Stress and advancing age are associated with impaired digestion and absorption due to inadequate production of digestive enzymes.,,, About 20% of individuals over age 60 with no history of a gastrointestinal disorder or surgery have evidence of PI. Symptoms of mild PI can include bloating, cramping, increased flatulence, and diarrhea, much like IBS, which is also associated with vitamin deficiencies.
Due to the risk for nutrient insufficiency, individuals with digestive difficulties may benefit from multivitamin and mineral supplementation.,, In addition, supplemental digestive enzymes,,, bile acids, and probiotics, may facilitate digestion and improve nutrient status in many individuals with these conditions. Probiotic and prebiotic supplementation can aid in restoring the microbiota to a healthier state.,, Along with other direct benefits, probiotics have been shown to increase vitamin D absorption and thereby reduce vitamin D deficiency.,,
The absorptive capacity of the intestine declines with age, which affects the bioavailability of vitamin B12, calcium, vitamin D, and other micronutrients., The body’s ability to absorb certain vitamins and minerals depends on many factors including adequate levels of stomach acid. Hypochlorhydria, a condition of having lower levels of stomach acid than one should, is more common with increasing age., Low stomach acid can occur as a consequence of chronic atrophic autoimmune gastritis, Helicobacter pylori infection,, or the use of acid-suppressing medications such as proton-pump inhibitors (PPIs; used to treat acid reflux and heartburn, discussed further below). Low acid conditions are known to impair the release of protein-bound vitamin B12 contained in food, and reduce the absorption of β-carotene, folate, iron, calcium, zinc, and vitamin D.,,,,,
Medications that reduce nutrient bioavailability
The use of antibiotics disrupts the gut microbiota and increases the risk of nutrient insufficiency.
Last but not least, a plethora of different medications can reduce nutrient bioavailability. Some notorious examples include acid-suppressing medications, noted above, which are associated with multiple nutrient insufficiencies;,, metformin, a diabetes drug, which can reduce levels of folic acid and vitamin B12;, diuretics (water pills), which deplete the body of magnesium and other minerals; and statins (cholesterol-lowering medicine), which reduce serum levels of coenzyme Q10 (CoQ10) and vitamin K2., The use of antibiotics disrupts the gut microbiota and increases the risk of nutrient insufficiency. Antibiotics are used to treat infections, but they also eliminate the healthy bacteria that play a key role in the absorption and metabolism of micronutrients.,,,, Probiotics can help restore a more normal microbiota during and after antibiotic treatment.
As many other medications can cause nutrient depletion, it may be helpful to consult a health professional to determine if a medication you take is putting you at risk. Read the literature that comes with your prescription, and look up more about the drug on a reliable website, such as the National Institutes of Health.
Chemical, biological, and physiological factors all influence nutrient bioavailability. If you take supplements, do some research to identify the most bioactive form of the nutrient, and choose a supplier whose formulations are backed by research. Individuals with digestive difficulties and/or taking medications may benefit from multivitamin and mineral supplementation to prevent insufficiencies. (Note: if you have a chronic digestive disorder, be sure to consult a health professional to identify the cause.) Supplemental digestive enzymes and bile acids can help support digestion and improve nutrient status in many individuals. Probiotic and prebiotic supplementation can aid in restoring the microbiota to a healthier state, which improves nutrient status and overall health.Click here to see References
 Parada J, et al. Food microstructure affects the bioavailability of several nutrients. J Food Sci. 2007 Mar;72(2):R21-32.
 D’Archivio M, et al. Bioavailability of the polyphenols: status and controversies. Int J Mol Sci. 2010 Mar 31; 11(4):1321-42.
 Gibson RS. The role of diet-and host-related factors in nutrient bioavailability and thus in nutrient-based dietary requirement estimates. Food Nutr Bull. 2007 Mar;28(1_suppl1):S77-100.
 Atkinson SA, Koletzko B. Determining life-stage groups and extrapolating nutrient intake values (NIVs). Food Nutr Bull. 2007 Mar;28(1_suppl1):S61-76.
 Schönfeldt HC, et al. Bioavailability of nutrients. In: Caballero B, Finglas P, Toldrá F, eds. The Encyclopedia of Food and Health. 2016 Jan 1;1:401-6.
 Houghton LA, Vieth R. The case against ergocalciferol (vitamin D2) as a vitamin supplement. Am J Clin Nutr. 2006 Oct;84(4):694-7.
 Logan VF, et al. Long-term vitamin D3 supplementation is more effective than vitamin D2 in maintaining serum 25-hydroxyvitamin D status over the winter months. Br J Nutr. 2013 Mar 28;109(6):1082-8.
 Tripkovic L, et al. Daily supplementation with 15 mcg vitamin D2 compared with vitamin D3 to increase wintertime 25-hydroxyvitamin D status in healthy South Asian and white European women: a 12-wk randomized, placebo-controlled food-fortification trial. Am J Clin Nutr. 2017 Aug;106(2):481-90.
 Jiang Q. Natural forms of vitamin E: metabolism, antioxidant, and anti-inflammatory activities and their role in disease prevention and therapy. Free Radic Biol Med. 2014 Jul;72:76-90.
 Wong RS, Radhakrishnan AK. Tocotrienol research: past into present. Nutr Rev. 2012 Sep;70(9):483-90.
 Ghani SMA, et al. Comparing the effects of vitamin E tocotrienol-rich fraction supplementation and α-tocopherol supplementation on gene expression in healthy older adults. Clinics (Sao Paulo). 2019 Mar 7;74:e688.
 Breyer I, Azzi A. Differential inhibition by alpha- and beta-tocopherol of human erythroleukemia cell adhesion: role of integrins. Free Radic Biol Med. 2001 Jun 15;30(12):1381-9.
 Peh HY, et al. Vitamin E therapy beyond cancer: tocopherol versus tocotrienol. Pharmacol Ther. 2016 Jun;162:152-69.
 Shen CL, et al. Tocotrienols for bone health: a translational approach. Ann N Y Acad Sci. 2017 Aug;1401(1):150-65.
 Theriault A, et al. Tocotrienol is the most effective vitamin E for reducing endothelial expression of adhesion molecules and adhesion to monocytes. Atherosclerosis. 2002 Jan;160(1):21-30.
 Schurgers LJ, Vermeer C. Differential lipoprotein transport pathways of K-vitamins in healthy subjects. Biochim Biophys Acta. 2002 Feb 15;1570(1):27-32.
 Shearer MJ, Newman P. Metabolism and cell biology of vitamin K. Thromb Haemost. 2008 Oct;100(4):530-47.
 Schurgers LJ, et al. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. 2007 Apr 15;109(8):3279-83.
 Halder M, et al. Vitamin K: double bonds beyond coagulation insights into differences between vitamin K1 and K2 in health and disease. Int J Mol Sci. 2019 Feb 19;20(4):896.
 Villa JKD, et al. Effect of vitamin K in bone metabolism and vascular calcification: A review of mechanisms of action and evidences. Crit Rev Food Sci Nutr. 2017 Dec 12;57(18):3959-70.
 Knapen MH, et al. Vitamin K2 supplementation improves hip bone geometry and bone strength indices in postmenopausal women. Osteoporos Int. 2007 Jul;18(7):963-72.
 Schwalfenberg GK. Vitamins K1 and K2: the emerging group of vitamins required for human health. J Nutr Metab. 2017;2017:6254836.
 Shea MK, et al. Association of vitamin K status combined with vitamin D status and lower-extremity function: a prospective analysis of two knee osteoarthritis cohorts. Arthritis Care Res (Hoboken). 2018 Aug;70(8):1150-9.
 Gonçalves RF, et al. Advances in nutraceutical delivery systems: from formulation design for bioavailability enhancement to efficacy and safety evaluation. Trends Food Sci Technol. 2018 Aug 1;78:270-91.
 Scalbert A, Williamson G. Dietary intake and bioavailability of polyphenols. J Nutr. 2000 Aug;130(8S Suppl):2073S-85S.
 Gupta SC, et al. Discovery of curcumin, a component of golden spice, and its miraculous biological activities. Clin Exp Pharmacol Physiol. 2012 Mar;39(3):283-99.
 Anand P, et al. Bioavailability of curcumin: problems and promises. Mol Pharm. 2007 Nov-Dec;4(6):807-18.
 Kotha RR, Luthria DL. Curcumin: biological, pharmaceutical, nutraceutical, and analytical aspects. Molecules. 2019 Aug 13;24(16):2930.
 Dei Cas M, Ghidoni R. Dietary curcumin: correlation between bioavailability and health potential. Nutrients. 2019 Sep 8;11(9):2147.
 Lao CD, et al. Dose escalation of a curcuminoid formulation. BMC Complement Altern Med. 2006 Mar 17;6:10.
 Jäger R, et al. Comparative absorption of curcumin formulations. Nutr J. 2014 Jan 24;13:11.
 Margulies SL, et al. Vitamin D deficiency in patients with intestinal malabsorption syndromes–think in and outside the gut. J Dig Dis. 2015 Nov;16(11):617-33.
 Fletcher J, et al. The role of vitamin D in inflammatory bowel disease: mechanism to management. Nutrients. 2019 May 7;11(5):1019.
 Chu AS, et al. Nutrient deficiency-related dermatoses after bariatric surgery. Adv Skin Wound Care. 2019 Oct;32(10):443-55.
 Hammond N, et al. Nutritional neuropathies. Neurol Clin. 2013 May;31(2):477-89.
 Weisshof R, Chermesh I. Micronutrient deficiencies in inflammatory bowel disease. Curr Opin Clin Nutr Metab Care. 2015 Nov;18(6):576-81.
 Ehrlich S, et al. Micronutrient deficiencies in children with inflammatory bowel diseases. Nutr Clin Pract. 2019 Jul 25. [Epub ahead of print]
 Parizadeh SM, et al. Vitamin D in inflammatory bowel disease: from biology to clinical implications. Complement Ther Med. 2019 Dec;47:102189.
 Bermejo F, et al. Should we monitor vitamin B12 and folate levels in Crohn’s disease patients? Scand J Gastroenterol. 2013 Nov;48(11):1272-7.
 Borel P. Factors affecting intestinal absorption of highly lipophilic food microconstituents (fat-soluble vitamins, carotenoids and phytosterols). Clin Chem Lab Med. 2003 Aug;41(8):979-94.
 Singh VK, et al. Less common etiologies of exocrine pancreatic insufficiency. World J Gastroenterol. 2017 Oct 21;23(39):7059-76.
 Perbtani Y, Forsmark CE. Update on the diagnosis and management of exocrine pancreatic insufficiency. F1000Research. 2019;8:F1000 Faculty Rev-1991.
 Albahrani AA, Greaves RF. Fat-soluble vitamins: clinical indications and current challenges for chromatographic measurement. Clin Biochem Rev. 2016 Feb;37(1):27-47.
 Loli H, et al. Lipases in medicine: an overview. Mini Rev Med Chem. 2015;15(14):1209-16.
 Modolell I, et al. Gastrointestinal, liver, and pancreatic involvement in adult patients with cystic fibrosis. Pancreas. 2001 May;22(4):395-9.
 Sherf Dagan S, et al. Nutritional recommendations for adult bariatric surgery patients: clinical practice. Adv Nutr. 2017 Mar 15;8(2):382-94.
 Leeds JS, et al. Some patients with irritable bowel syndrome may have exocrine pancreatic insufficiency. Clin Gastroenterol Hepatol. 2010 May;8(5):433-8.
 Piciucchi M, et al. Exocrine pancreatic insufficiency in diabetic patients: prevalence, mechanisms, and treatment. Int J Endocrinol. 2015;2015:595649.
 Godala M, et al. The risk of plasma vitamin A, C, E and D deficiency in patients with metabolic syndrome: a case-control study. Adv Clin Exp Med. 2017 Jul;26(4):581-6.
 Farnetti S, et al. Functional and metabolic disorders in celiac disease: new implications for nutritional treatment. J Med Food. 2014 Nov;17(11):1159-64.
 Leeds JS, et al. Is exocrine pancreatic insufficiency in adult coeliac disease a cause of persisting symptoms? Aliment Pharmacol Ther. 2007 Feb 1;25(3):265-71.
 Zaidel O, Lin HC. Uninvited guests: the impact of small intestinal bacterial overgrowth on nutritional status. Practical Gastroenterology. 2003 Jul:27-34.
 Pitchumoni CS, et al. Pancreatitis in inflammatory bowel diseases. J Clin Gastroenterol. 2010 Apr;44(4):246-53.
 Fabisiak N, et al. Fat-soluble vitamin deficiencies and inflammatory bowel disease: systematic review and meta-analysis. J Clin Gastroenterol. 2017 Nov/Dec;51(10):878-89.
 Colombel JF, et al. AGA clinical practice update on functional gastrointestinal symptoms in patients with inflammatory bowel disease: expert review. Clin Gastroenterol Hepatol. 2019 Feb;17(3):380-90.
 Rothenbacher D, et al. Prevalence and determinants of exocrine pancreatic insufficiency among older adults: results of a population-based study. Scand J Gastroenterol. 2005 Jun;40(6):697-704.
 Laugier R, et al. Changes in pancreatic exocrine secretion with age: pancreatic exocrine secretion does decrease in the elderly. Digestion. 1991;50(3-4):202-11.
 Campbell JA, et al. PWE-208 How common is pancreatic exocrine insufficiency in primary care? Gut. 2015 Jun 1;64:A303.
 Salvatore S, et al. Low fecal elastase: potentially related to transient small bowel damage resulting from enteric pathogens. J Pediatr Gastroenterol Nutr. 2003 Mar;36(3):392-6.
 Hardt PD, et al. High prevalence of exocrine pancreatic insufficiency in diabetes mellitus. A multicenter study screening fecal elastase 1 concentrations in 1,021 diabetic patients. Pancreatology. 2003;3(5):395-402.
 Ramos LR, et al. Inflammatory bowel disease and pancreatitis: a review. J Crohns Colitis. 2016 Jan;10(1):95-104.
 Herzig KH, et al. Fecal pancreatic elastase-1 levels in older individuals without known gastrointestinal diseases or diabetes mellitus. BMC Geriatr. 2011 Jan 25;11:4.
 Williams CE, et al. Vitamin D status in irritable bowel syndrome and the impact of supplementation on symptoms: what do we know and what do we need to know? Eur J Clin Nutr. 2018 Oct;72(10):1358-63.
 Sikkens EC, et al. The prevalence of fat-soluble vitamin deficiencies and a decreased bone mass in patients with chronic pancreatitis. Pancreatology. 2013 May-Jun;13(3):238-42.
 Pham A, Forsmark C. Chronic pancreatitis: review and update of etiology, risk factors, and management. F1000Res. 2018 May 17;7:F1000 Faculty Rev-607.
 Löhr JM, et al. The ageing pancreas: a systematic review of the evidence and analysis of the consequences. J Intern Med. 2018 May;283(5):446-60.
 Roxas M. The role of enzyme supplementation in digestive disorders. Altern Med Rev. 2008 Dec;13(4):307-14.
 Ianiro G, et al. Digestive enzyme supplementation in gastrointestinal diseases. Curr Drug Metab. 2016;17(2):187-93.
 Graham DY, et al. Enzyme therapy for functional bowel disease-like post-prandial distress. J Dig Dis. 2018 Nov;19(11):650-6.
 Pezzilli R. Chronic pancreatitis: maldigestion, intestinal ecology and intestinal inflammation. World J Gastroenterol. 2009 Apr 14;15(14):1673-6.
 LeBlanc JG, et al. Bacteria as vitamin suppliers to their host: a gut microbiota perspective. Curr Opin Biotechnol. 2013 Apr;24(2):160-8.
 Drabińska N, et al. Beneficial effect of oligofructose-enriched inulin on vitamin D and E status in children with celiac disease on a long-term gluten-free diet: a preliminary randomized, placebo-controlled nutritional intervention study. Nutrients. 2018 Nov 15;10(11):1768.
 Didari T, et al. Effectiveness of probiotics in irritable bowel syndrome: Updated systematic review with meta-analysis. World J Gastroenterol. 2015 Mar 14;21(10):3072-84.
 Costanzo M, et al. Krill oil, vitamin D and Lactobacillus reuteri cooperate to reduce gut inflammation. Benef Microbes. 2018 Apr 25;9(3):389-99.
 Jones ML, et al. Oral supplementation with probiotic L. reuteri NCIMB 30242 increases mean circulating 25-hydroxyvitamin D: a post hoc analysis of a randomized controlled trial. J Clin Endocrinol Metab. 2013 Jul;98(7):2944-51.
 de Moreno de LeBlanc A, et al. Vitamin producing lactic acid bacteria as complementary treatments for intestinal inflammation. Antiinflamm Antiallergy Agents Med Chem. 2018;17(1):50-6.
 Nilsson-Ehle H. Age-related changes in cobalamin (vitamin B12) handling. Implications for therapy. Drugs Aging. 1998 Apr;12(4):277-92.
 Russell RM. The aging process as a modifier of metabolism. Am J Clin Nutr. 2000 Aug;72(2 Suppl):529S-32S.
 Holt PR, et al. Causes and consequences of hypochlorhydria in the elderly. Dig Dis Sci. 1989 Jun;34(6):933-7.
 Russell TL, et al. Upper gastrointestinal pH in seventy-nine healthy, elderly, North American men and women. Pharm Res. 1993 Feb;10(2):187-96.
 Cavalcoli F, et al. Micronutrient deficiencies in patients with chronic atrophic autoimmune gastritis: a review. World J Gastroenterol. 2017 Jan 28;23(4):563-72.
 Rodriguez-Castro KI, et al. Clinical manifestations of chronic atrophic gastritis. Acta Biomed. 2018 Dec 17;89(8-S):88-92.
 Yago MR, et al. Gastric reacidification with betaine HCl in healthy volunteers with rabeprazole-induced hypochlorhydria. Mol Pharm. 2013 Nov 4;10(11):4032-7.
 King CE, et al. Clinically significant vitamin B12 deficiency secondary to malabsorption of protein-bound vitamin B12. Dig Dis Sci. 1979 May;24(5):397-402.
 Tang G, et al. Gastric acidity influences the blood response to a beta-carotene dose in humans. Am J Clin Nutr. 1996 Oct;64(4):622-6.
 Russell RM, et al. Folic acid malabsorption in atrophic gastritis. Possible compensation by bacterial folate synthesis. Gastroenterology. 1986 Dec;91(6):1476-82.
 Skikne BS, et al. Role of gastric acid in food iron absorption. Gastroenterology. 1981 Dec;81(6):1068-71.
 Sturniolo GC, et al. Inhibition of gastric acid secretion reduces zinc absorption in man. J Am Coll Nutr. 1991 Aug;10(4):372-5.
 Russell RM. Factors in aging that effect the bioavailability of nutrients. J Nutr. 2001 Apr;131(4 Suppl):1359S-61S.
 Massironi S, et al. Relevance of vitamin D deficiency in patients with chronic autoimmune atrophic gastritis: a prospective study. BMC Gastroenterol. 2018 Nov 8;18(1):172.
 Heidelbaugh JJ, et al. Proton pump inhibitors and risk of vitamin and mineral deficiency: evidence and clinical implications. Ther Adv Drug Saf. 2013 Jun;4(3):125-33.
 Miller JW. Proton pump inhibitors, H2-receptor antagonists, metformin, and vitamin B-12 deficiency: clinical implications. Adv Nutr. 2018 Jul 1;9(4):511S-8S.
 Sheen E, Triadafilopoulos G. Adverse effects of long-term proton pump inhibitor therapy. Dig Dis Sci. 2011 Apr;56(4):931-50.
 Alvarez M, et al. Vitamin B12 deficiency and diabetic neuropathy in patients taking metformin: a cross-sectional study. Endocr Connect. 2019 Oct 1;8(10):1324-9.
 Greenberg A. Diuretic complications. Am J Med Sci. 2000 Jan;319(1):10-24.
 Littlefield N, et al. Statins’ effect on plasma levels of coenzyme Q10 and improvement in myopathy with supplementation. J Am Assoc Nurse Pract. 2014 Feb;26(2):85-90.
 Okuyama H, et al. Statins stimulate atherosclerosis and heart failure: pharmacological mechanisms. Expert Rev Clin Pharmacol. 2015 Mar;8(2):189-99.
 Magnúsdóttir S, et al. Systematic genome assessment of B-vitamin biosynthesis suggests co-operation among gut microbes. Front Genet. 2015 Apr 20;6:148.
 Aziz F, Patil P. Role of prophylactic vitamin K in preventing antibiotic induced hypoprothrombinemia. Indian J Pediatr. 2015 Apr;82(4):363-7.
 Aydin S. Can vitamin K synthesis altered by dysbiosis of microbiota be blamed in the etiopathogenesis of venous thrombosis? Biosci Microbiota Food Health. 2017;36(3):73-4.
 Conly JM, et al. The contribution of vitamin K2 (menaquinones) produced by the intestinal microflora to human nutritional requirements for vitamin K. Am J Gastroenterol. 1994 Jun;89(6):915-23.
 Wagatsuma K, et al. Diversity of gut microbiota affecting serum level of undercarboxylated osteocalcin in patients with Crohn’s disease. Nutrients. 2019 Jul 8;11(7):1541.
 Sniffen JC, et al. Choosing an appropriate probiotic product for your patient: an evidence-based practical guide. PLoS One. 2018 Dec 26;13(12):e0209205.
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Marina MacDonald, MS, PhD
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