Effect of hypochlorhydria due to omeprazole treatment or atrophic gastritis on protein-bound vitamin B12 absorption

Effect of Long-Term Proton Pump Inhibitor Use on Blood Vitamins and Minerals: A Primary Care Setting Study

BACKGROUND AND OBJECTIVES

Long-term proton pump inhibitor (PPI) use is frequently encountered in primary care. Its effect on micronutrient absorption is known, as vitamin B12, calcium or vitamin D insufficiency may occur in such patients.

MATERIALS AND METHODS

We recruited patients using a PPI (pantoprazole) for >12 months. The control group was represented by subjects attending the general practitioner not taking any PPI in the last 12 months. We excluded subjects using nutritional supplements or with diseases interfering with micronutrient blood levels. All subjects underwent blood sampling with full blood count, iron, ferritin, vitamin D, calcium, sodium, potassium, phosphate, zinc and folate.

RESULTS

We recruited 66 subjects: 30 in the PPI group and 36 in the control group. Long-term pantoprazole users had lower red blood cell count but similar hemoglobin. We did not find any significant difference in blood iron, ferritin, vitamin B12 and folate. Vitamin D deficit was observed more frequently in the PPI group (100%) than in controls (30%, p < 0.001), with blood levels lower in pantoprazole consumers. No differences in calcium, sodium and magnesium were observed. Pantoprazole users had lower phosphate levels than controls. Finally, a non-significant trend for zinc deficiency was found in PPI users.

CONCLUSIONS

Our study confirms that chronic PPI users may encounter alterations in some micronutrients involved in bone mineral homeostasis. The effect on zinc levels deserves further investigation.

Vitamin B12 deficiency and use of proton pump inhibitors: a systematic review and meta-analysis

BACKGROUND

Proton pump inhibitors (PPI) may impact the absorption of vitamin B12. We performed a systematic review to ascertain if PPI use increases risk of vitamin B12 deficiency.

METHODS

Electronic databases (Pubmed, Embase, Scopus) were searched on first of September 2022. We selected studies that compared the frequency of vitamin B12 deficiency in PPI users and non-users. Pooled Odds Ratio (OR) was calculated for the occurrence of vitamin B12 deficiency in PPI users compared to non-users. The risk of bias was assessed using the Newcastle Ottawa scale.

RESULTS

Twenty-five studies were included. The pooled OR of vitamin B12 deficiency among PPI users (2852 participants) was higher than non-users (28070 participants) (OR 1.42, 95% CI: 1.16-1.73; I² = 54%). Overall risk of PPI use among vitamin B12 deficient individuals was higher than those without deficiency (OR 1.49, 1.20-1.85; I² = 68%). Most studies found no difference between serum vitamin B12 levels among PPI users compared to non-users.

CONCLUSION

Although the pooled OR of vitamin B12 deficiency was slightly increased in PPI users, but there was significant heterogeneity, and the pooled OR was too low to imply an association clearly. Better-designed prospective studies in long-term users may clarify the issue.

REGISTRATION

This study was not registered on PROSPERO.

Mechanistic Link between Vitamin B12 and Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common form of dementia in the elderly population, affecting over 55 million people worldwide. Histopathological hallmarks of this multifactorial disease are an increased plaque burden and tangles in the brains of affected individuals. Several lines of evidence indicate that B12 hypovitaminosis is linked to AD. In this review, the biochemical pathways involved in AD that are affected by vitamin B12, focusing on APP processing, Aβ fibrillization, Aβ-induced oxidative damage as well as tau hyperphosphorylation and tau aggregation, are summarized. Besides the mechanistic link, an overview of clinical studies utilizing vitamin B supplementation are given, and a potential link between diseases and medication resulting in a reduced vitamin B12 level and AD are discussed. Besides the disease-mediated B12 hypovitaminosis, the reduction in vitamin B12 levels caused by an increasing change in dietary preferences has been gaining in relevance. In particular, vegetarian and vegan diets are associated with vitamin B12 deficiency, and therefore might have potential implications for AD. In conclusion, our review emphasizes the important role of vitamin B12 in AD, which is particularly important, as even in industrialized countries a large proportion of the population might not be sufficiently supplied with vitamin B12.

Gastroprotective Effects of Spirulina platensis, Golden Kiwifruit Flesh, and Golden Kiwifruit Peel Extracts Individually or in Combination against Indomethacin-Induced Gastric Ulcer in Rats

This study was conducted to investigate the therapeutic effect of hydro-alcoholic extract of Spirulina platensis (SP), golden kiwifruit (Actinidia chinensis) flesh (KF), and golden kiwifruit peel (KP) individually or in combination (SFP) on indomethacin-induced gastric ulcer in rats. Negative control rats (GI) were orally administered distilled water in parallel with other treatments. The positive control rat group (GII) was administered 30 mg kg⁻¹ indomethacin to induce gastric ulcers. The KF and KF extracts were used individually or together with SP in treating indomethacin-induced gastric ulcerated rat groups. Gastric ulcerated rat’s groups GIII, GIV, GV, GVI, and GVII were orally administered at 30 mg kg⁻¹ rat body weight as total phenolic content (TPC) equivalent from SP, KF, KP, SPF extracts, and Lansoprazole (30 mg kg⁻¹, as reference drug) daily up to 14 days, respectively. The relevant biochemical parameters, antioxidant biomarkers, and histopathological examination were examined. Remarkably, treating rats with SP, KF, KP, and SFP extracts markedly reduced gastric juice and stomach volume expansion induced by indomethacin. The SP significantly retrieved the pH of gastric juice to a regular rate compared to GI. The ulcer index (UI) was significantly attenuated by SP, KF, KP, and SFP administration. The protection index percentage (PI %) was 80.79, 54.51, 66.08, 75.74, and 74.86% in GIII, GIV, GV, GVI, and GVII, respectively. The gastric mucin content was significantly better attenuated by 95.7 in GIII compared to its content in GI. Lansoprazole increased mucin content by 80.3%, which was considerably lower than SP and SFP. SP, KF, KP, SFP, and Lansoprazole improved the reform of gastric mucosal-increased secreted mucus by 95.6, 61.3, 64.8, 103.1, and 80.2% in GIII, GIV, GV, GVI, and GVII, respectively. Interestingly, SFP efficiently increased vit. B₁₂ level by 46.0% compared to other treatments. While Lansoprazole administrating did not significantly attenuate vit. B₁₂ level. The SP and SFP improved iron and Hemoglobin (HB) levels depending on treatment. SP, KF, KP, and SFP significantly decreased the malondialdehyde (MDA) and increased reduced glutathione (GSH) as well as superoxide dismutase (SOD) levels in blood and stomach tissues. The most potent effect was observed with SP, and SFP was even better than Lansoprazole. Histopathologically, treating rats with SP extract showed a marked reduction of gastric damage and severity changes induced by indomethacin. KP was much better than KF in lessening gastric histopathological damages caused by indomethacin. SFP significantly alleviates gastric histopathological alterations. The lansoprazole-treated group (GVII) greatly relieved the gastric histopathological changes and recorded mild focal necrosis and desquamation of the mucosa in addition to mild oedema in the serosal layer. In conclusion, the presented results proved the antiulcer potential of SP and A. chinensis extracts against an indomethacin-induced gastric ulcer in rats, which may be due to their antioxidant and anti-inflammation efficiency. Thus, these data suggested that SP, KF, KP, and SFP extracts as natural and safe alternatives have a gastroprotective potential against indomethacin-induced gastric ulceration. The antioxidative and anti-inflammatory properties are probable mechanisms.

Ethnicity influences total serum vitamin B12 concentration: a study of Black, Asian and White patients in a primary care setting

AIMS

A growing body of evidence suggests that ethnicity and race influence vitamin B₁₂ metabolism and status yet clinical awareness of this is poor, causing doubts regarding diagnosis and treatment. Moreover, deficiency and insufficiency cut-offs are universally applied for this test in most diagnostic settings. The objective of this study was to assess serum vitamin B₁₂ concentrations in Black, Asian and White primary care patients in London, UK, particularly in patients of Black or Black British ethnic origin and establish if there is a need for specific reference ranges.

METHODS

Serum B₁₂ results from 49 414 patients were processed between January 2018 and November 2019 using the Architect assay (Abbott Diagnostics) at St. Thomas' Hospital, London, UK. Age, sex and ethnicity data were collected from the laboratory Health Informatics Team.

RESULTS

Black patients (n=13 806) were found to have significantly higher serum vitamin B₁₂ concentration across all age groups and both sexes, especially Nigerian patients (median B₁₂ 505 pmol/L,IQR: 362-727, n=891), compared with Asian and White ethnic groups (p<0.001). Binary logistic regression analysis revealed that the Black or Black British ethnic group had the strongest association with elevated serum B₁₂ (>652 pmol/L) (adjusted OR 3.38, 95% CI 3.17 to 3.61, p<0.0001).

CONCLUSIONS

It is likely that a combination of genetic and acquired/environmental factors are responsible for the ethnic differences in serum B₁₂. This suggests that there is a need for ethnic-specific reference ranges with indications for the incorporation of age and sex too.

Vitamin B12 status in health and disease: a critical review. Diagnosis of deficiency and insufficiency - clinical and laboratory pitfalls

Vitamin B₁₂ (cobalamin) is an essential cofactor for two metabolic pathways. It is obtained principally from food of animal origin. Cobalamin becomes bioavailable through a series of steps pertaining to its release from dietary protein, intrinsic factor-mediated absorption, haptocorrin or transcobalamin-mediated transport, cellular uptake, and two enzymatic conversions (via methionine synthase and methylmalonyl-CoA-mutase) into cofactor forms: methylcobalamin and adenosylcobalamin. Vitamin B₁₂ deficiency can masquerade as a multitude of illnesses, presenting different perspectives from the point of view of the hematologist, neurologist, gastroenterologist, general physician, or dietician. Increased physician vigilance and heightened patient awareness often account for its early presentation, and testing sometimes occurs during a phase of vitamin B₁₂ insufficiency before the main onset of the disease. The chosen test often depends on its availability rather than on the diagnostic performance and sensitivity to irrelevant factors interfering with vitamin B₁₂ markers. Although serum B₁₂ is still the most commonly used and widely available test, diagnostics by holotranscobalamin, serum methylmalonic acid, and plasma homocysteine measurements have grown in the last several years in routine practice. The lack of a robust absorption test, coupled with compromised sensitivity and specificity of other tests (intrinsic factor and gastric parietal cell antibodies), hinders determination of the cause for depleted B₁₂ status. This can lead to incorrect supplementation regimes and uncertainty regarding later treatment. This review discusses currently available knowledge on vitamin B₁₂, informs the reader about the pitfalls of tests for assessing its deficiency, reviews B₁₂ status in various populations at different disease stages, and provides recommendations for interpretation, treatment, and associated risks. Future directions for diagnostics of B₁₂ status and health interventions are also discussed.

Effect of Food and Dosing Regimen on Safety and Efficacy of Proton Pump Inhibitors Therapy-A Literature Review

Proton pump inhibitors (PPIs) are the first-choice drugs used to prevent and treat acid-related diseases. However, a lack of satisfactory response to the standard PPI dose ("PPI failure") is often reported, especially in patients with gastroesophageal reflux disease. Poor compliance seems to be one of the main causes of PPI failure; hence, it is crucial to gain knowledge on how to properly administer PPIs. In this review, we aimed to evaluate the effect of food, beverages, and dosing regimen on pharmacokinetics and pharmacodynamics of PPIs and to frame recommendations for healthcare professionals to improve both patient's counseling and compliance to treatment with PPIs. A total of 201 papers were identified following a literature search. After full-text evaluation, 64 studies were included in the review. Co-administration of PPIs with a meal may affect both their bioavailability and effectiveness; however, the influence of food depends on the type of drug and its formulation. Except for pantoprazole, PPIs can be administered in the morning or evening; however, morning intake generally provides better daytime control of gastric acidity. In most cases, the choice of the proper schedule of administration should be based on the patient's symptoms and individual dosing preferences.

Depression, Hematologic Parameters, and Blood Levels of Vitamin B12 in Patients With Laryngopharyngeal Reflux Under Use of Proton Pump Inhibitors

Objective

The objective of this study was to evaluate and correlate hematologic indices, vitamin B₁₂ levels, and depression in patients with suspected laryngopharyngeal reflux (LPR) treated with proton pump inhibitor (PPI).

Methods

This was a prospective study with a population (n = 23) consisted of patients with suspected LPR and treated with 2 daily doses of Omeprazole 40 mg (80 mg or full dose). The study volunteers performed a complete blood count and vitamin B₁₂ dosage before and after 3 and 6 months of treatment, as well as depression screening using the Center of Epidemiologic Studies-Depression (CES-D) questionnaire before and after 6 months of treatment. Scores greater than 16 were considered as suggestive of depression.

Results

The mean score on the CES-D scale of study participants at baseline significantly decreased after 6 months of treatment. A significant decrease was observed in the red blood cells count (RBC) after 6 months in relation to 3 months. Significant increases in mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were observed from 3 months to 6 months in this study. Vitamin B₁₂ levels increased significantly between baseline and after 6 months of treatment.

Conclusion

Decreased scores on the CES-D scale were associated with increased MCV values, with no association with vitamin B₁₂ levels. However, vitamin B₁₂ levels also increased significantly after 6 months of treatment with PPI.

Important drug-micronutrient interactions: A selection for clinical practice

Interactions between drugs and micronutrients have received only little or no attention in the medical and pharmaceutical world in the past. Since more and more pharmaceutics are used for the treatment of patients, this topic is increasingly relevant. As such interactions - depending on the duration of treatment and the status of micronutrients - impact the health of the patient and the action of the drugs, physicians and pharmacists should pay more attention to such interactions in the future. This review aims to sensitize physicians and pharmacists on drug micronutrient interactions with selected examples of widely pescribed drugs that can precipitate micronutrient deficiencies. In this context, the pharmacist, as a drug expert, assumes a particular role. Like no other professional in the health care sector, he is particularly predestined and called up to respond to this task. The following article intends to point out the relevance of mutual interactions between micronutrients and various examples of widely used drugs, without claiming to be exhaustive.

Molecular Regulation of Histamine Synthesis

Histamine is a critical mediator of IgE/mast cell-mediated anaphylaxis, a neurotransmitter and a regulator of gastric acid secretion. Histamine is a monoamine synthesized from the amino acid histidine through a reaction catalyzed by the enzyme histidine decarboxylase (HDC), which removes carboxyl group from histidine. Despite the importance of histamine, transcriptional regulation of HDC gene expression in mammals is still poorly understood. In this review, we focus on discussing advances in the understanding of molecular regulation of mammalian histamine synthesis.

Evidence of Drug-Nutrient Interactions with Chronic Use of Commonly Prescribed Medications: An Update

The long-term use of prescription and over-the-counter drugs can induce subclinical and clinically relevant micronutrient deficiencies, which may develop gradually over months or even years. Given the large number of medications currently available, the number of research studies examining potential drug-nutrient interactions is quite limited. A comprehensive, updated review of the potential drug-nutrient interactions with chronic use of the most often prescribed medications for commonly diagnosed conditions among the general U.S. adult population is presented. For the majority of the interactions described in this paper, more high-quality intervention trials are needed to better understand their clinical importance and potential consequences. A number of these studies have identified potential risk factors that may make certain populations more susceptible, but guidelines on how to best manage and/or prevent drug-induced nutrient inadequacies are lacking. Although widespread supplementation is not currently recommended, it is important to ensure at-risk patients reach their recommended intakes for vitamins and minerals. In conjunction with an overall healthy diet, appropriate dietary supplementation may be a practical and efficacious way to maintain or improve micronutrient status in patients at risk of deficiencies, such as those taking medications known to compromise nutritional status. The summary evidence presented in this review will help inform future research efforts and, ultimately, guide recommendations for patient care.

Population Reference Values for Serum Methylmalonic Acid Concentrations and Its Relationship with Age, Sex, Race-Ethnicity, Supplement Use, Kidney Function and Serum Vitamin B12 in the Post-Folic Acid Fortification Period

Serum methylmalonic acid (MMA) is elevated in vitamin B-12 deficiency and in kidney dysfunction. Population reference values for serum MMA concentrations in post-folic acid fortification period are lacking. Aims of this study were to report the population reference values for serum MMA and to evaluate the relation between serum MMA and sex, age, race-ethnicity, kidney dysfunction and vitamin B-12. We used data from three National Health and Nutrition Examination Surveys, 1999–2000, 2001–2002 and 2003–2004 conducted after folic acid fortification commenced (n = 18,569). Geometric mean MMA was ≈22.3% higher in non-Hispanic white compared to non-Hispanic black (141.2 vs. 115.5 nmol/L) and was ≈62.7% higher in >70 years old persons compared to 21–30 years old persons (196.9 vs. 121.0 nmol/L). Median serum MMA was ≈28.5% higher in the 1st the quartile of serum vitamin B-12 than in the 4th quartile of serum vitamin B-12 and was ≈35.8% higher in the 4th quartile of serum creatinine than in the 1st quartile of serum creatinine. Multivariate-adjusted serum MMA concentration was significantly associated with race-ethnicity (p < 0.001) and age (p < 0.001) but not with sex (p = 0.057). In this large US population based study, serum MMA concentrations presented here reflect the post-folic acid fortification scenario. Serum MMA concentrations begin to rise at the age of 18–20 years and continue to rise afterwards. Age-related increase in serum MMA concentration is likely to be due to a concomitant decline in kidney function and vitamin B-12 status.

Are proton pump inhibitors really so dangerous?

For decades, millions of patients with acid-related disorders have had their acid inhibited effectively and safely first with H2-receptor antagonists (H2RAs) and then with proton pump inhibitors (PPI). As with any pharmacological agent, PPIs have been reported to be associated with some adverse events, but several recent large-scale observational studies have evidenced new and serious abnormalities generally linked to their chronic use. However, these studies have often important limitations for their frequent retrospective design and other methodological drawbacks, such as selection biases of the analyzed populations and the presence of various confounding factors. Overall, although the conclusions of these pharmacovigilant investigations must be taken into account and can generate important hypotheses for future research, they do not have to create panic among patients and alarmism among physicians. On considering the weakness of these studies, we suggest physicians should not refrain from continuing to use PPIs, if these drugs are given for medical indications clearly established in the literature and, more importantly, they should not be induced to shift to H2RAs, a class of antisecretory agents that are much less effective than PPIs. A return to the past is potentially dangerous for the patients, taking into account the well-known success of PPIs in the wide spectrum of all acid-related conditions.

Vitamin B12 Deficiency Induced by the Use of Gastric Acid Inhibitors: Calcium Supplements as a Potential Effect Modifier

OBJECTIVE

Use of gastric acid inhibitors has emerged as a risk factor of vitamin B12 deficiency, especially in older adults. Calcium supplements could be an effect modifier of this relationship by its role in the absorption process of vitamin B12. The aim of this study is to examine whether the use of calcium supplements could be an effect modifier of the association between gastric acid inhibitors and vitamin B12 deficiency.

DESIGN

Cross-sectional study based on medical chart reviews.

SETTING

Geriatric Assessment Unit (GAU) of a university-affiliated hospital.

PARTICIPANTS

The study included 172 patients discharged from the GAU between 2008 and 2012.

MEASUREMENTS

Cases of vitamin B12 deficiency were identified as those who had received a diagnosis of vitamin B12 deficiency, and/or were receiving a treatment for vitamin B12 deficiency. Use of gastric acid inhibitors and calcium supplements at admission was determined from the pharmacist report. Associations between medications and vitamin B12 status were investigated using logistic regression models.

RESULTS

Seventy-one patients (41%) had vitamin B12 deficiency. At admission, 42% were taking gastric acid inhibitors and 45% calcium supplements. After adjustment for covariates, analyses revealed that vitamin B12 deficiency was more likely among users of gastric acid inhibitors who did not concomitantly received calcium supplements [OR=3.12; P=0.01]. Conversely, no significant association was observed in patients using both, gastric acid inhibitors and calcium supplements [OR=1.30; P=0.59].

CONCLUSIONS

The present study provides the very first evidence that the use of calcium supplements could be an effect modifier of the association between gastric acid inhibitors and vitamin B12 deficiency. Failure to consider calcium supplements as an effect modifier could have led to biased risk estimates in previous published studies.

Exploring the role of cranberry polyphenols in periodontits: A brief review

Cranberry juice polyphenols have gained importance over the past decade due to their promising health benefits. The bioactive component, proanthocyanidins is mainly responsible for its protective effect. A lot has been said about its role in urinary tract infection and other systemic diseases, but little is known about its oral benefits. An extensive search was carried out in the PubMed database using the terms "cranberry polyphenols" and "periodontitis" together. The institute library was also thoroughly scrutinized for all relevant information. Thus, a paper was formulated, the aim of which was to review the role of high molecular weight cranberry fraction on oral tissues and periodontal diseases.

Gastroesophageal reflux disease and the elderly

Gastroesophageal reflux disease is a common disorder in all patients but a particular problem in the elderly, for whom the disease often presents with advanced mucosal damage and other complications. Symptoms are also not as reliable an indication of disease severity in older patients. Likewise, therapy is more difficult because of potential side effects and drug interactions.

Effects of widely used drugs on micronutrients: a story rarely told

Vitamins and trace elements are essential to the body, however, deficiencies are frequently observed in the general population. Diet is mostly responsible for these deficiencies but drugs also may play a significant role by influencing their metabolism. These effects are rarely assessed in clinical practice, in part because of limited data available in the literature. Drug-induced micronutrient depletions, however, may be the origin of otherwise unexplained symptoms that might sometimes influence medication compliance. We present various examples of widely prescribed drugs that can precipitate micronutrient deficiencies. This review aims at sensitizing physicians on drug-micronutrient interactions. High-risk population groups also are presented and supplementation protocols are suggested.

[Long-term proton pump inhibitor therapy and osteoporosis. Is there a real danger?]

Proton pump inhibitors are widely used in the treatment of acid-related diseases because they are considered to be effective and safe. In the past 10 years the use of proton pump inhibitors increased by over three folds, which is not associated with the increased prevalence of acid-related diseases obviously. However, like any other drugs, they have potential side effects. In recent years many studies have been published about the correlation between long-term proton pump inhibitor therapy and the increase of bone fractures. Most studies showed that long-term proton pump inhibitor therapy moderately increased fracture risk. The underlying mechanisms of increased number of bone fractures are not clarified yet. However, chronic acid suppression caused by long-term proton pump inhibitor therapy may play a crucial role in decreased absorption of calcium and vitamin B12 and, therefore, indirectly affecting the bones resulting in a decrease of bone mineral density. The available data suggest that proton pump inhibitors should be used with caution in patients with increased risk of osteoporosis.

Vitamin B12 and ageing: current issues and interaction with folate

A compromised vitamin B12 status is common in older people despite dietary intakes that typically far exceed current recommendations. The maintenance of an optimal status of vitamin B12 is not only dependent on adequate dietary intake but more critically on effective absorption which diminishes with age. The measurement of vitamin B12 is complicated by the lack of a gold standard assay. There are a number of direct and functional indicators of vitamin B12 status; however, none of these are without limitations and should be used in combination. Vitamin B12 is of public health importance, not only because deficiency leads to megaloblastic anaemia and irreversible nerve damage, but also because emerging evidence links low B12 to an increased risk of a number of age-related diseases, including cardiovascular disease, cognitive dysfunction, dementia and osteoporosis. Furthermore, there are concerns relating to potential adverse effects for older adults with low vitamin B12 status of over-exposure to folic acid in countries where there is mandatory fortification of food with folic acid. The aim of this review is to examine the known and emerging issues related to vitamin B12 in ageing, its assessment and inter-relationship with folate.

Proton pump inhibitors: potential adverse effects

PURPOSE OF REVIEW

This review summarizes adverse effects of potential proton pump inhibitors (PPIs), including nutritional deficiencies (B12 and magnesium), rebound acid hypersecretion, acute interstitial nephritis, gastric carcinoid tumor, cardiovascular risk with clopidogrel and PPI coprescription, bone fractures, enteric infections and pneumonia. An epidemiologic framework is applied to assess clinical relevance and reinforce best practice recommendations.

RECENT FINDINGS

The evidence for PPI adverse events is limited by the absence of Level 1 (randomized controlled trial) studies. The best evidence supports Clostridium difficile and bone fractures in susceptible populations. A substantial reduction in gastrointestinal bleeding risk without increase in cardiovascular events was observed in the COGENT trial when clopidogrel was coprescribed with omeprazole. The risk of pneumonia is inconsistent, and although acute interstitial nephritis, nutritional deficiencies (including B12 and hypomagnesemia), gastric carcinoid and rebound hyperacidity are biologically plausible, studies have failed to demonstrate supportive clinical relevance.

SUMMARY

Prescribe PPI for robust indications only. Strong data supporting risk of adverse events are lacking; however, exercise caution in the elderly and in patients with other risk factors for bone fractures or C. difficile infection.

Effects of Omeprazole on Vitamin and Mineral Absorption and Metabolism

Objective:

To examine the literature surrounding the effects of omeprazole on oral iron absorption and discuss the long-term use of omeprazole and its effect on vitamins C and B12, calcium, and magnesium absorption.

Data Sources:

The PubMed and MEDLINE databases were searched for reports published in English between January 1968 and August 2012, using the terms absorption, ascorbic acid, proton pump inhibitor, omeprazole, magnesium, calcium, ferrous sulfate, iron, and drug interactions.

Study Selection and Data Extraction:

Studies and reports published in English were selected for review. In some cases, reference citations from selected review articles were evaluated as well.

Data Synthesis:

Several micronutrients require an acidic environment for optimal absorption. Iron, vitamin C, and vitamin B12absorption are dependent on the intestine's acidic environment. Several studies and case reports describe associations of omeprazole with altered calcium, magnesium, and vitamin B12absorption. To date, there have been no prospective trials evaluating the effect of proton pump inhibitors (PPIs) on iron absorption.

Conclusions:

Existing data support the conclusion that the acid-suppressing effect of omeprazole can have important clinical implications for vitamin and mineral therapy. Clinicians should be cognizant of this issue in practice. Further studies exploring the relationship of PPIs and iron deficiency are warranted, especially in high-risk populations such as the elderly.

[Adverse effects of proton pump inhibitors: should we worry about long-term exposure?]

Long-term treatment with proton pump inhibitors (PPI) is becoming more prevalent. Although they are well tolerated in the short term, serious concerns about long-term use have arisen. Recent data suggest that the latter is associated with an increased risk for osteoporotic fracture (especially vertebral), Clostridium difficile infection and rebound acid hypersecretion after treatment discontinuation. Acute interstitial nephritis is rare but may progress to chronic renal failure. An increased risk of community-acquired pneumonia has not been established in the general population and seems limited to the most vulnerable patients. Consistent data are still missing to correctly assess the risk of iron deficiency, vitamin B12 deficiency or hypomagnesaemia and the risk of digestive malignant diseases, despite the pathophysiological basis that exists concerning gastric malignancy. Many drug interactions can occur on long-term treatment, including some that imply the cytochrome P450 enzymes. Finally, the risk-benefit balance for a chronic PPI use in children seems unfavorable in most cases.

Population prevalence, attributable risk, and attributable risk percentage for high methylmalonic acid concentrations in the post-folic acid fortification period in the US

BACKGROUND

Serum methylmalonic acid (MMA) is regarded as a sensitive marker of vitamin B-12 status. Elevated circulating MMA is linked to neurological abnormalities. Contribution of age, supplement use, kidney dysfunction, and vitamin B-12 deficiency to high serum MMA in post-folic acid fortification period is unknown.

METHODS

We investigated prevalence, population attributable risk (PAR), and PAR% for high MMA concentrations in the US. Data from 3 cross-sectional National Health and Nutrition Examination Surveys conducted in post-folic acid fortification period were used (n = 18569).

RESULTS

Likelihood of having high serum MMA for white relative to black was 2.5 (P < 0.0001), ≥ 60 y old persons relative to < 60 y old persons was 4.0 (P < 0.0001), non-supplement users relative to supplement users was 1.8 (P < 0.0001), persons with serum creatinine ≥ 130 μmol/L relative to those with < 130 μmol/L was 12.6 (P < 0.0001), and persons with serum vitamin B-12 < 148 pmol/L relative to those with ≥ 148 pmol/L was 13.5 (P < 0.0001). PAR% for high MMA for old age, vitamin B-12 deficiency, kidney dysfunction, and non-supplement use were 40.5, 16.2, 13.3, and 11.8, respectively. By improving serum vitamin B-12 (≥ 148 pmol/L), prevalence of high MMA would be reduced by 16-18% regardless of kidney dysfunction.

CONCLUSIONS

Old age is the strongest determinant of PAR for high MMA. About 5 cases of high serum MMA/1000 people would be reduced if vitamin B-12 deficiency (< 148 pmol/L) is eliminated. Large portion of high MMA cases are not attributable to serum vitamin B-12. Thus, caution should be used in attributing high serum MMA to vitamin B-12 deficiency.

Safety of proton pump inhibitor exposure

Proton pump (H(+)/K(+)-adenosine triphosphatase) inhibitors (PPIs) are widely used to treat patients with acid-related disorders because they are generally perceived to be safe and effective. However, as with any pharmacologic agent, they have the potential for side effects. Many studies have examined the side effects of long-term or short-term PPI exposure. We review the mechanism of action of PPIs, focusing on recently released products that might have greater risks of adverse effects than older products because of increased potency and/or duration of action. We summarize the data available on the putative adverse effects of PPI therapy and propose guidelines for clinicians who prescribe these agents to limit the potential for adverse outcomes in users of these effective therapeutic agents.

Safety of the long-term use of proton pump inhibitors

The proton pump inhibitors (PPIs) as a class are remarkably safe and effective for persons with peptic ulcer disorders. Serious adverse events are extremely rare for PPIs, with case reports of interstitial nephritis with omeprazole, hepatitis with omeprazole and lansoprazole, and disputed visual disturbances with pantoprazole and omeprazole. PPI use is associated with the development of fundic gland polyps (FGP); stopping PPIs is associated with regression of FGP. In the absence of Helicobacter pylori infection, the long-term use of PPIs has not been convincingly proven to cause or be associated with the progression of pre-existing chronic gastritis or gastric atrophy or intestinal metaplasia. Mild/modest hypergastrinemia is a physiological response to the reduction in gastric acid secretion due to any cause. The long-term use of PPIs has not been convincingly proven to cause enterochromaffin-like cell hyperplasia or carcinoid tumors. PPIs increase the risk of community acquired pneumonia, but not of hospital acquired (nosocomial) pneumonia. There is no data to support particular care in prescribing PPI therapy due to concerns about risk of hip fracture with the long-term use of PPIs. Long-term use of PPIs does not lead to vitamin B12 deficiencies, except possibly in the elderly, or in persons with Zollinger-Ellison Syndrome who are on high doses of PPI for prolonged periods of time. There is no convincingly proven data that PPIs increase the risk of Clostridium difficile-associated diarrhea in persons in the community. The discontinuation of PPIs may result in rebound symptoms requiring further and even continuous PPI use for suppression of symptoms. As with all medications, the key is to use PPIs only when clearly indicated, and to reassess continued use so that long-term therapy is used judiciously. Thus, in summary, the PPIs are a safe class of medications to use long-term in persons in whom there is a clear need for the maintenance of extensive acid inhibition.

Hip fracture risk in patients with a diagnosis of pernicious anemia

BACKGROUND & AIMS

Pernicious anemia (PA) is characterized by vitamin B-12 deficiency and achlorhydria, both of which have a detrimental effect on bone strength. The principle aim of this study was to determine the risk of hip fracture in patients with PA.

METHODS

This is a retrospective cohort study using the General Practice Research Database (GPRD) from the United Kingdom. GPRD data from May 1987 until April 2002 were utilized to identify patients between 40 and 90 years of age at the time of GPRD enrollment. The exposed group contained patients with a diagnosis of PA being treated with vitamin B-12 therapy. We matched each patient having a diagnosis of PA with 4 randomly selected non-PA patients with respect to age (+/-1 year) and sex. Cox regression analysis was used to determine the hazard ratio (HR) for hip fracture associated with PA.

RESULTS

Nine thousand five hundred six patients with a diagnosis of PA receiving vitamin B-12 injection therapy were identified and compared to 38,024 controls. Patients with PA had a greater risk of hip fracture than the controls (HR = 1.74; 95% CI: 1.45-2.08). The increase in hip fracture risk was even more pronounced among those patients newly diagnosed with PA during GPRD follow-up (HR = 2.63; 95% CI: 2.03-3.41).

CONCLUSIONS

Patients with a diagnosis of PA have an elevated risk of hip fracture. The increased hip fracture risk was persistent even years after vitamin B-12 therapy. Chronic achlorhydria could be the mechanism contributing to the persistently elevated hip fracture risk.

Cranberry and urinary tract infections

Urinary tract infection (UTI) refers to the presence of clinical signs and symptoms arising from the genitourinary tract plus the presence of one or more micro-organisms in the urine exceeding a threshold value for significance (ranges from 102 to 103 colony-forming units/mL). Infections are localized to the bladder (cystitis), renal parenchyma (pyelonephritis) or prostate (acute or chronic bacterial prostatitis). Single UTI episodes are very common, especially in adult women where there is a 50-fold predominance compared with adult men. In addition, recurrent UTIs are also common, occurring in up to one-third of women after first-episode UTIs. Recurrences requiring intervention are usually defined as two or more episodes over 6 months or three or more episodes over 1 year (this definition applies only to young women with acute uncomplicated UTIs). A cornerstone of prevention of UTI recurrence has been the use of low-dose once-daily or post-coital antimicrobials; however, much interest has surrounded non-antimicrobial-based approaches undergoing investigation such as use of probiotics, vaccines, oligosaccharide inhibitors of bacterial adherence and colonization, and bacterial interference with immunoreactive extracts of Escherichia coli. Local (intravaginal) estrogen therapy has had mixed results to date. Cranberry products in a variety of formulations have also undergone extensive evaluation over several decades in the management of UTIs. At present, there is no evidence that cranberry can be used to treat UTIs. Hence, the focus has been on its use as a preventative strategy. Cranberry has been effective in vitro and in vivo in animals for the prevention of UTI. Cranberry appears to work by inhibiting the adhesion of type I and P-fimbriated uropathogens (e.g. uropathogenic E. coli) to the uroepithelium, thus impairing colonization and subsequent infection. The isolation of the component(s) of cranberry with this activity has been a daunting task, considering the hundreds of compounds found in the fruit and its juice derivatives. Reasonable evidence suggests that the anthocyanidin/proanthocyanidin moieties are potent antiadhesion compounds. However, problems still exist with standardization of cranberry products, which makes it extremely difficult to compare products or extrapolate results. Unfortunately, most clinical trials have had design deficiencies and none have evaluated specific key cranberry-derived compounds considered likely to be active moieties (e.g. proanthocyanidins). In general, the preventive efficacy of cranberry has been variable and modest at best. Meta-analyses have established that recurrence rates over 1 year are reduced approximately 35% in young to middle-aged women. The efficacy of cranberry in other groups (i.e. elderly, paediatric patients, those with neurogenic bladder, those with chronic indwelling urinary catheters) is questionable. Withdrawal rates have been quite high (up to 55%), suggesting that these products may not be acceptable over long periods. Adverse events include gastrointestinal intolerance, weight gain (due to the excessive calorie load) and drug-cranberry interactions (due to the inhibitory effect of flavonoids on cytochrome P450-mediated drug metabolism). The findings of the Cochrane Collaboration support the potential use of cranberry products in the prophylaxis of recurrent UTIs in young and middle-aged women. However, in light of the heterogeneity of clinical study designs and the lack of consensus regarding the dosage regimen and formulation to use, cranberry products cannot be recommended for the prophylaxis of recurrent UTIs at this time.

Prevalence and outcome of anemia after restorative proctocolectomy: a clinical literature review

PURPOSE

Iron and/or vitamin B12 deficiency anemias, which have adverse effects on patients' quality of life, are commonly observed and often overlooked complications after restorative proctocolectomy. We performed a systematic review of publications on the prevalence of anemia as well as on the impact of anemia on a range of clinical, functional, quality of life, and economic outcomes in restorative proctocolectomy patients. This information is important to help healthcare providers through a comprehensive overview to increase awareness about a condition that could require therapy to improve patient healthcare and quality of life.

METHODS

We reviewed the English language publications on the incidence of anemia and its adverse effect after restorative proctocolectomy The United States National Library of Medicine database (MEDLINE), the Excerpta Medica database (EMBASE), the Cochran Library, and the Google search engine were searched for published articles on the prevalence and impact of anemia in post-restorative proctocolectomy surgical patients.

RESULTS

The long-term complication most frequently described after RPC is pouchitis. Pouchitis is significantly associated with iron deficiency anemia caused by pouch mucosal bleeding. Other causes are insufficient and/or impaired iron absorption. It has also been observed, however, that restorative proctocolectomy patients with underlying familial adenomatous polyposis rarely develop pouchitis yet show higher rates of iron deficiency anemia compared to those patients with underlying ulcerative colitis. Other causes shown as independent risk factors for iron deficiency anemia in restorative proctocolectomy patients are malignancy, desmoid tumors, and J-pouch configuration. Vitamin B12 deficiency anemia is also common after restorative proctocolectomy. About one-third of restorative proctocolectomy patients show abnormal Schilling test and 5 percent have low referenced serum cobalamin. It has been observed that the degree resection of the terminal-ileum, malabsorption, bacterial overgrowth, and dietary factors are among the known causes of cobalamin deficiency. Folate deficiency has not been reported in restorative proctocolectomy patients. Describing restorative proctocolectomy surgery and its outcomes, in patients without anemia, the quality of life is reported excellent regardless of operative technique.

CONCLUSIONS

Anemia is not uncommon following restorative proctocolectomy and has been shown to have negative effects on the patient's quality of life and the economy and may substantially increase healthcare costs. The treatment of anemia and its underlying causes is important to improving clinical and economic outcomes.

Long-term garlic or micronutrient supplementation, but not anti-Helicobacter pylori therapy, increases serum folate or glutathione without affecting serum vitamin B-12 or homocysteine in a rural Chinese population

The effects of a 7.3-y supplementation with garlic and micronutrients and of anti-Helicobacter pylori treatment with amoxicillin (1 g twice daily) and omeprazole (20 mg twice daily) on serum folate, vitamin B-12, homocysteine, and glutathione concentrations were assessed in a rural Chinese population. A randomized, double-blind, placebo-controlled, factorial trial was conducted to compare the ability of 3 treatments to retard the development of precancerous gastric lesions in 3411 subjects. The treatments were: 1) anti-H. pylori treatment with amoxicillin and omeprazole; 2) 7.3-y supplementation with aged garlic and steam-distilled garlic oil; and 3) 7.3-y supplementation with vitamin C, vitamin E, and selenium. All 3 treatments were given in a 2(3) factorial design to subjects seropositive for H. pylori infection; only the garlic supplement and vitamin and selenium supplement were given in a 2(2) factorial design to the other subjects. Thirty-four subjects were randomly selected from each of the 12 treatment strata. Sera were analyzed after 7.3 y to measure effects on folate, vitamin B-12, homocysteine, and glutathione concentrations. Regression analyses adjusted for age, gender, and smoking indicated an increase of 10.2% (95%CI: 2.9-18.1%) in serum folate after garlic supplementation and an increase of 13.4% (95%CI: 5.3-22.2%) in serum glutathione after vitamin and selenium supplementation. The vitamin and selenium supplement did not affect other analytes and the amoxicillin and omeprazole therapy did not affect any of the variables tested. In this rural Chinese population, 7.3 y of garlic supplementation increased the serum folate concentration and the vitamin and selenium supplement increased that of glutathione, but neither affected serum concentrations of vitamin B-12 or homocysteine.

Long-term use of proton pump inhibitors and vitamin B12 status in elderly individuals

BACKGROUND

Some studies have shown that short-term use of proton pump inhibitors decreases the absorption of vitamin B12, but the results of studies into long-term proton pump inhibitor use and vitamin B12 deficiency are inconsistent.

AIM

To investigate whether long-term proton pump inhibitor use is associated with an abnormal vitamin B12 status in elderly individuals.

METHODS

One hundred and twenty-five long-term (>3, years) proton pump inhibitor users aged 65, years and above were recruited from general practices. Their 125 partners (who did not use proton pump inhibitors) served as the reference group. Vitamin B12 status was determined by serum levels of vitamin B12 and homocysteine, and mean corpuscular volume.

RESULTS

No differences in mean vitamin B12 levels were observed between the long-term proton pump inhibitor users and their partners [345 (s.d. 126), pm vs. 339 (s.d. 133), pm, P, =, 0.73], even after adjustment for age, gender, Helicobacter pylori status and C-reactive protein levels (P, =, 0.87). Four proton pump inhibitor users and three partners had vitamin B12 levels <150, pm (3% vs. 2%, P, =, 1.00). No differences between the groups were observed in homocysteine levels and mean corpuscular volume.

CONCLUSIONS

No association between long-term proton pump inhibitor use and vitamin B12 status was observed. Regular testing for low vitamin B12 levels in elderly patients on long-term treatment with proton pump inhibitors is therefore not recommended.

Consequences of long-term proton pump blockade: insights from studies of patients with gastrinomas

Proton pump inhibitors are being increasingly used and for longer periods of time, especially in patients with gastroesophageal reflux disease. Each of these trends has led to numerous studies and reviews of the potential risk-benefit ratio of the long-term use of proton pump inhibitors. Both long-term effects of hypergastrinaemia due to the profound acid suppression caused by proton pump inhibitors as well as the effects of hypo-/achlorhydria per se have been raised and studied. Potential areas of concern that have been raised in the long-term use of proton pump inhibitors, which could alter this risk-benefit ratio include: gastric carcinoid formation; the development of rebound acid hypersecretion when proton pump inhibitor treatment is stopped; the development of tolerance; increased oxyntic gastritis in H. pylori patients and the possibility of increasing the risk of gastric cancer; the possible stimulation of growth of non-gastric tumours due to hypergastrinaemia; and the possible effect of the hypo/achlorhydria on nutrient absorption, particularly iron and vitamin B12. Because few patients with idiopathic gastro-oesophageal reflux disease/peptic ulcer disease have been treated long-term (i.e., >10 years), there is little known to address the above areas of potential concern. Most patients with gastrinomas with Zollinger-Ellison syndrome have life-long hypergastrinaemia, require continuous proton pump inhibitors treatment and a number of studies report results of >5-10 years of tratment and follow-up. Therefore, an analysis of Zollinger-Ellison syndrome patients can provide important insights into some of the safety concerns raised above. In this paper, results from studies of Zollinger-Ellison syndrome patients and other recent studies dealing with the safety concerns above, are briefly reviewed.

Management of gastroesophageal reflux disease

Gastroesophageal reflux disease is the most common and expensive digestive disease with complex and multi-factorial pathophysiologic mechanisms. Transient inappropriate relaxation of the lower esophageal sphincter is the predominant mechanism in the majority of patients with mild to moderate disease. Hiatal hernias and a reduced lower esophageal sphincter pressure have a significant role in patients with moderate to severe disease. Typical manifestations of gastroesophageal reflux disease include heartburn, regurgitation, and dysphagia. Atypical symptoms, such as noncardiac chest pain, pulmonary manifestations of asthma, cough, aspiration pneumonia, or ENT manifestations of globus and laryngitis, can be seen in patients with or without typical symptoms of gastroesophageal reflux disease. Endoscopy and ambulatory pH tests are best to evaluate the anatomic and physiologic impact ofgastroesophageal reflux disease. Complications of chronic gastroesophageal reflux disease include peptic strictures and Barrett metaplasia. Barrett esophagus is a major risk factor for esophageal adenocarcinoma, and upper endoscopy with surveillance biopsies is recommended for patients with Barrett esophagus. Medical therapy with anti-secretory agents (H2 blockers and proton pump inhibitors) is effective for most patients with gastroesophageal reflux disease. Surgical fundoplications and endoscopic treatment modalities are mechanical treatment options for patients with gastroesophageal reflux disease.

The pathogenesis of gastrointestinal bacterial overgrowth

The normal indigenous intestinal microflora consists of about 10(15) bacteria that under physiological conditions reside mainly in the lower gastrointestinal tract. Bacterial overgrowth implies abnormal bacterial colonization of the upper gut, resulting from failure of specific defense mechanisms restricting colonization under physiological conditions. At present two types of bacterial overgrowth with defined pathogenesis can be distinguished: (1) gastric overgrowth with upper respiratory tract microflora resulting from selective failure of the gastric acid barrier, and (2) gastrointestinal overgrowth with Gram-negative bacilli (enteric bacteria) resulting from failure of intestinal clearance. Helicobacter pylori-induced gastritis of the oxyntic mucosa is the main cause of acquired failure of the gastric acid barrier, which is common among the healthy elderly. Intestinal clearance may fail as the result of impaired intestinal peristalsis or anatomical abnormalities that alter luminal flow. Impaired peristalsis is associated with conditions interfering with intestinal neuromuscular function including myopathic, neuropathic, autoimmune, infectious, inflammatory, metabolic, endocrine, and neoplastic diseases. Anatomical abnormalities are mainly the result of gastrointestinal surgery, intestinal diverticula or fistula. Combined failure of intestinal clearance and the gastric acid barrier results in more severe colonization with Gram-negative bacilli. Gram-negative bacilli are uncommon in the upper gut of otherwise healthy individuals with gastric hypochlorhydria, being acquired (H. pylori) or drug-induced. Significant bacterial overgrowth with Gram-negative bacilli is a rational in the search for an explanation to optimize clinical management. The clinical significance of colonization with upper respiratory tract microflora remains unclear. Translocation of live bacteria, their metabolic products, or antigens from a small bowel colonized by Gram-negative bacilli play a role in the pathogenesis of spontaneous bacterial peritonitis in hepatic disease and in certain types of sepsis, indicating that further studies can point to new patient populations with potential benefit from medical treatment.

A case-control study on adverse effects: H2 blocker or proton pump inhibitor use and risk of vitamin B12 deficiency in older adults

OBJECTIVE

Acid-suppressant drugs are commonly prescribed for elderly patients, a population in which vitamin B(12) deficiency is a common disorder. The purpose of this study was to examine the possible association between use of prescription histamine H-2 receptor antagonists (H2RA) or proton pump inhibitors (PPI) and vitamin B(12) deficiency in older adults.

STUDY DESIGN AND SETTING

This was a case-control study in a University-based geriatric primary care setting. Among patients aged 65 years or older with documented serum vitamin B(12) studies between 1990 and 1997, 53 vitamin B(12)-deficient cases were compared with 212 controls for past or current use of prescription H2RA/PPI according to information in subjects' medical records.

RESULTS

Controlling for age, gender, multivitamin use, and Helicobacter pylori infection, chronic (#10878;12 months) current use of H2RA/PPI was associated with a significantly increased risk of vitamin B(12) deficiency (OR 4.45; 95% CI 1.47-13.34). No association was found between past or short-term current use of H2RA/PPI and vitamin B(12) deficiency.

CONCLUSION

These findings support an association between chronic use of H2RA/PPI by older adults and development of vitamin B(12) deficiency. Additional studies are needed to confirm these findings.

Modern approaches to the investigation of vitamin B12 deficiency

The classic workup of a patient for possible PA is revisited in light of the vanishing Schilling test. The vagaries of testing for B12 and blocking antibodies are reexamined. The advantages and disadvantages of newer tests such as MMA and serum gastrin levels are catalogued. At this juncture in the evolution of new test strategies, there is a considerable controversy regarding the significance of high MMA levels in the face of normal B12 levels, particularly in the elderly. Hopefully, this controversy will soon be resolved and the newer crop of tests will be proven and accepted in the workplace. Still, the words of Alexander Pope spring to mind: "Be not the first by whom the new are tried, Nor yet the last to lay the old aside."

Vitamin B(12) deficiency associated with histamine(2)-receptor antagonists and a proton-pump inhibitor

OBJECTIVE

To report a case of vitamin B(12) deficiency associated with long-term use (approximately 4 1/2 y) of histamine(2) (H(2))-receptor antagonists and a proton-pump inhibitor (PPI) in a patient with gastroesophageal reflux.

CASE SUMMARY

A 78-year-old nonvegetarian white woman with symptomatic gastroesophageal reflux (GER) was started on cimetidine 300 mg 4 times daily in February 1990 and took various other antisecretory medications over the course of the next 4 1/2 years. She had a normal serum vitamin B(12) concentration of 413 pg/mL in August 1992. In June 1994, her serum vitamin B(12) concentration was found to be in the low normal range at 256 pg/mL. Biochemical markers of vitamin B(12)-dependent enzyme activity were measured at that time, and methylmalonic acid (MMA) and homocysteine (HCYS) were elevated at 757 nmol/L and 27.3 micromol/L, respectively. Serum folate was within the normal range at 4.9 ng/mL, and serum creatinine was slightly elevated at 1.4 mg/dL. MMA and HCYS concentrations decreased dramatically with oral replacement of vitamin B(12) 1000 microg/d, which confirmed vitamin B(12) deficiency. Oral replacement also demonstrated that the woman was able to adequately absorb nonprotein-bound vitamin B(12) from the gastrointestinal tract, suggesting that her deficiency was a result of food-cobalamin malabsorption. The accumulation of MMA and HCYS was not a consequence of renal dysfunction, since both metabolites dramatically decreased with vitamin B(12) replacement.

DISCUSSION

Malabsorption of dietary protein-bound vitamin B(12) has been demonstrated with the use of H(2)-receptor antagonists and PPIs. One previous case report of vitamin B(12) deficiency resulting from long-term use of omeprazole has been published. The malabsorption of dietary vitamin B(12) is thought to be a result of its impaired release from food protein, which requires gastric acid and pepsin as the initial step in the absorption process.

CONCLUSIONS

The use of H(2)-receptor antagonists and/or PPIs may impair the absorption of protein-bound dietary vitamin B(12) and could contribute to the development of vitamin B(12) deficiency with prolonged use. Patients taking these medications for extended periods of time, particularly >4 years, should be monitored for vitamin B(12) status.

Changes in gastric mucosa and luminal environment during acid-suppressive therapy: a review in depth

Acid-suppressive therapy and subsequent changes in gastric mucosa and luminal environment rank highly amongst the investigated issues in gastroenterology over the past two to three decades. Herewith, we present an overview of these intragastric changes, particularly during long-term administration of acid-suppresive medication and concurrent infection with Helicobacter pylori. Current evidence indicates that: i) Long-term acid suppression facilitates the development of fundic ECL cell hyperplasia, especially in the presence of Helicobacter pylori. No neoplastic changes directly attributable to acid suppression have so far been demonstrated in humans. ii) Acid-suppressive therapy increases the risk of enteric infections. iii) Acid-suppressive therapy does not alter fat and mineral bioavailability, but may decrease the absorption of protein-bound vitamin B12. iv) Acid suppression invariably results in intragastric overgrowth of non-Helicobacter pylori bacterial species. The concurrent infection with Helicobacter pylori may promote this bacterial overgrowth and the intragastric formation of N-nitrosamines. v) Acid-suppressive therapy alters the natural course of Helicobacter pylori gastritis, transforming the antral-predominant pattern into a body-predominant pattern, which in turn may progress to body gland atrophy. The pathophysiology of this phenomenon is currently under investigation. vi) In view of the potential adverse effects of acid suppression in the presence of Helicobacter pylori, the screen-and-treat strategy is advocated for Helicobacter pylori in subjects considered for long-term treatment.

Gastrinoma

Gastrinoma treatment has evolved considerably in the last 20 years. In particular, the advent of effective acid-reducing pharmacologic agents has changed the primary morbidity of this disease entity from one of acid hypersecretion to one of tumor growth and spread. Thus, while symptoms can be temporized using histamine receptor antagonists, proton pump inhibitors, or somatostatin analogs, cure can be effected only by surgical means. Recent advances in operative techniques and pre- and intra-operative imaging studies, including routine duodenotomy, somatostatin-receptor scintigraphy, and intraoperative ultrasound, have allowed for identification and subsequent resection of more than 95% of gastrinoma tumors. Most experts agree that all sporadic cases of localized gastrinoma should be excised. In addition, debulking of metastatic tumor may improve symptoms and survival when cure cannot be ascertained. There is, however, some controversy as to the surgical approach for gastrinoma found in the setting of multiple endocrine neoplasia, type 1. Because of the usual multiplicity and particular indolence of these tumors, two primary strategies have emerged: aggressive approaches have been advocated in an effort to eradicate all present and potential tumor; and less aggressive, or nonoperative, approaches have been suggested because it is unclear whether intervention offers survival or disease-free benefit in this population. We advocate surgical intervention for patients with gastrinoma and multiple endocrine neoplasia, type 1 when tumors exceed 2.5 cm in size. This tumor size has been associated with a higher likelihood of hepatic metastases, which ultimately affects survival. The role of adjuvant therapies for gastrinoma remains limited.

Alteration in digestion and absorption of nutrients during profound acid suppression

Gastric acid suppression therapy has for many years been the cornerstone of the treatment of peptic disease. The availability of more potent inhibitors of gastric acid secretion and the increasing demand for maintenance therapy has renewed interest in the potential side-effects of profound and/or long-lasting therapy. This chapter focuses on the potential interference of gastric acid suppression therapy with the process of the digestion and absorption of nutrients. The theoretical mechanisms by which hypochlorhydria resulting from gastric acid suppression therapy may hamper digestion and absorption are multiple and well documented. Clinical studies evaluating the effect of gastric acid suppression therapy on the assimilation of nutrients are, on the other hand, scarce and have, moreover, yielded conflicting results. The reason for the latter may be related, at least in part, to elements of study design. Data indicating overt malabsorption or clear deficiencies in patients on long-term gastric acid suppression therapy are currently lacking. Nevertheless, it seems prudent, while awaiting the results of additional long-term studies, regularly to monitor these patients, especially those with increased nutrient demand, poor intake or suboptimal stores.

The association between antiulcer medication and initiation of cobalamin replacement in older persons

As chronic use of antiulcer medications might predispose older persons to cobalamin deficiency, we studied participants (> 65 years) in the clinical examination of the Canadian Study of Health and Aging to test the association between the use of an antiulcer medication (histamine-2 blocker or proton pump inhibitor) at baseline with initiation of cobalamin replacement during the 5 year follow-up period. Of 1054 eligible subjects, 125 (11.7%) were taking an antiulcer medication at baseline. At follow-up, 49 (4.6%) had started cobalamin replacement. Antiulcer medication use at baseline was significantly associated with the initiation of cobalamin therapy (odds ratio 2.56, 95% confidence interval 1.30-5.05), even after adjusting for age, gender and institutional residence (odds ratio 2.61, 95% confidence interval 1.31-5.23). There is an independent association between the use of antiulcer medication and initiation of cobalamin therapy. While the relationship is not unambiguously causal, this finding underscores the need for judicious prescribing of antiulcer medications for older persons.

Proton pump inhibitors in the treatment of gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease (GERD) is the most common peptic acid disease in the western world and is the commonest indication for acid suppression therapy. Major advances have been made over the past 30 years in the understanding of lower oesophageal sphincter function and the mechanism of acid secretion. Developments in surgical and pharmacological therapy have paralleled these advances. Pharmacotherapy for GERD has evolved from antacids to H2-receptor antagonists (H2RAs) to prokinetics to proton pump inhibitors (PPIs). The H2RAs, while modestly effective in symptom relief and healing of GERD, are limited by pharmacological tolerance. The prokinetics (metoclopramide and cisapride) are limited by low efficacy, pharmacological tolerance and toxicity. The PPIs have emerged as the most effective therapy for symptom relief, healing and long-term maintenance. They have also proved to be remarkably safe and cost-effective in long-term therapy. This review evaluates the pharmacology, efficacy, tolerability, safety and cost-effectiveness of the four currently available PPIs, lansoprazole, omeprazole, pantoprazole and rabeprazole, in the treatment of GERD.

Current concepts in cobalamin deficiency

The application of sensitive metabolic tests, such as the deoxyuridine suppression test and measurement of homocysteine and methylmalonic acid, to cobalamin status has identified the entity of mild, preclinical cobalamin deficiency. This state, common in the elderly, responds to cobalamin therapy. Preclinical deficiency may exist within the nervous system as well, although this requires further study. Nevertheless, it is well to remember that not all low cobalamin levels and not all abnormal metabolite results reflect cobalamin deficiency. Interpretation of metabolic results still requires caution, as do proposals to raise the cut-off point for low cobalamin levels to capture some normal levels that are associated with metabolic abnormality. The recognition of mild, preclinical deficiency has opened up many important issues. These include identifying its causes, what should be done about it, and what the clinical impact of the hyperhomocysteinemia itself is. Although malabsorptive disorders, especially food-cobalamin malabsorption, underlie about half of all cases of preclinical deficiency, no cause can be found in the remainder of these cases; poor dietary intake appears to be uncommon. In addition, unusual states of neurologically symptomatic cobalamin deficiency are being recognized, such as nitrous oxide exposure in patients with unrecognized deficiency and severe deficiency in children of mildly deficient mothers. All of these have broadened and complicated the picture of cobalamin deficiency while providing greater opportunities for prevention.

Vitamin B12 levels during prolonged treatment with proton pump inhibitors

Reduced serum vitamin B12 (cobalamin) levels have been documented occasionally during long-term treatment with a proton pump inhibitor (PPI) in selected groups of patients. This has largely been confined to patients being treated for Zollinger-Ellison syndrome who have sustained drug-induced achlorhydria, which does not ordinarily occur during treatment with a PPI. An appreciation of normal cobalamin metabolism and the pharmacological action of the PPIs adequately explain the mechanism for this reduction. PPIs do not promote the development of pernicious anemia.