[{"@context":"https:\/\/schema.org\/","@type":"BlogPosting","@id":"https:\/\/www.regionalcancercare.org\/news\/vitamin-b12-deficiency\/#BlogPosting","mainEntityOfPage":"https:\/\/www.regionalcancercare.org\/news\/vitamin-b12-deficiency\/","headline":"Vitamin B12 Deficiency: 2 RCCA Hematologists Explain Its Causes, Risks, and Treatment\u2028","name":"Vitamin B12 Deficiency: 2 RCCA Hematologists Explain Its Causes, Risks, and Treatment\u2028","description":"Vitamin B12 Deficiency: 2 RCCA Hematologists Explain Its Causes, Risks, and Treatment\u2028 August 28, 2026 Sometimes, a vitamin deficiency can be corrected simply by eating more leafy green vegetables or taking a daily supplement. In the case of significant Vitamin B12 deficiency, however, a shot in the arm may be just what the doctor ordered […]","datePublished":"2026-08-28","dateModified":"2026-08-28","author":{"@type":"Person","@id":"https:\/\/www.regionalcancercare.org\/news\/author\/ceastway\/#Person","name":"ceastway","url":"https:\/\/www.regionalcancercare.org\/news\/author\/ceastway\/","identifier":5,"image":{"@type":"ImageObject","@id":"https:\/\/secure.gravatar.com\/avatar\/007b7979610c70c3cd4b24ed960fb78ff62c0b68401d393e79cb483d56812050?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/007b7979610c70c3cd4b24ed960fb78ff62c0b68401d393e79cb483d56812050?s=96&d=mm&r=g","height":96,"width":96}},"publisher":{"@type":"Organization","name":"Regional Cancer Care Associates","logo":{"@type":"ImageObject","@id":"https:\/\/www.regionalcancercare.org\/wp-content\/uploads\/2021\/08\/logo.svg","url":"https:\/\/www.regionalcancercare.org\/wp-content\/uploads\/2021\/08\/logo.svg","width":506,"height":228}},"image":{"@type":"ImageObject","@id":"https:\/\/www.regionalcancercare.org\/wp-content\/uploads\/2026\/08\/GettyImages-1218443675-scaled.jpg","url":"https:\/\/www.regionalcancercare.org\/wp-content\/uploads\/2026\/08\/GettyImages-1218443675-scaled.jpg","height":1422,"width":2560},"url":"https:\/\/www.regionalcancercare.org\/news\/vitamin-b12-deficiency\/","about":["All Cancers"],"wordCount":1787,"articleBody":"\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tVitamin B12 Deficiency: 2 RCCA Hematologists Explain Its Causes, Risks, and Treatment\u2028\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tAugust 28, 2026\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tSometimes, a vitamin deficiency can be corrected simply by eating more leafy green vegetables or taking a daily supplement. In the case of significant Vitamin B12 deficiency, however, a shot in the arm may be just what the doctor ordered \u2013 literally.Vinod Varki, MD, explains, \u201cUp to 95% of American adults have some degree of vitamin deficiency, with inadequate levels of Vitamins D, E, C, and A being the most common, in that order. Vitamin B12 deficiency is seen less often, but low levels of B12 require treatment to avoid potential problems including fatigue, neurological issues, heart palpitations, and low counts of the red blood cells that carry oxygen and the white blood cells that fight infection.\u201dDr. Varki, a board-certified medical oncologist and hematologist, adds that the prevalence of Vitamin B12 deficiency increases with age. \u201cResearch indicates that 3% or less of U.S. adults age 39 or younger have inadequate levels of B12, while that percentage climbs into the double digits among people aged 60 years or older, reaching 14% or even higher depending on the blood-level cutoff used to define deficiency,\u201d says Dr. Varki, who practices in the Riverdale, NJ, office of Regional Cancer Care Associates (RCCA), one of the nation\u2019s largest networks of oncology specialists. RCCA offers care at more than 20 locations near you in New Jersey, Connecticut, Massachusetts, and the Washington, D.C., area.Aging and the Risk of Vitamin B12 DeficiencyIan Horkheimer, MD, notes that the increase in Vitamin B12 deficiency seen with age is due, in large part, to the fact that three conditions that contribute to the deficiency are more common in older people. Dr. Horkheimer, a board-certified medical oncologist and hematologist who practices at RCCA\u2019s Little Silver, NJ office, explains, \u201cThe first of these conditions is pernicious anemia. This is an autoimmune disease that affects the lining of the stomach, causing malabsorption of dietary B12. The second condition is atrophic gastritis, another autoimmune disease that affects 8% to 9% of older adults. This form of gastritis decreases the body\u2019s production of a substance called intrinsic factor and reduces secretion of hydrochloric acid, impairing absorption of Vitamin B12. Third, Helicobacter pylori infection can cause inflammation, potentially leading to malabsorption of the vitamin.\u201dOther Risk Factors for Vitamin B12 DeficiencyBeyond older age, Dr. Horkheimer notes that several other factors can place a person at elevated risk for Vitamin B12 deficiency. He adds, \u201cThese risk factors can be divided into three broad categories. The first is inadequate intake of foods containing B12. This can be an issue for people who follow a strict vegetarian diet and for people who eat a lot of ultra-processed foods. The second category is inadequate absorption of B12 from foods containing the vitamin. Absorption issues can affect people with heavy alcohol use or gastrointestinal disorders such as Crohn\u2019s disease, as well as people who have had bariatric procedures and other gastrointestinal surgeries. Third, use of some medications, such as metformin or proton pump inhibitors, or exposure to substances such as nitrous oxide, can cause a B12 deficiency.\u201dWhy Diagnosing and Correcting Vitamin B12 Deficiency MatterDr. Varki notes that adequate levels of Vitamin B12 are critical for the development and function of the nervous system, the formation of healthy red blood cells, and the production of DNA, the genetic foundation of cells and of life itself.\u201cThe wide-ranging roles that Vitamin B12 plays explain why a significant deficiency of the vitamin can lead to a host of symptoms. Fortunately, the more extreme symptoms \u2013 such as vision problems or developing ulcers in the mouth \u2013 are uncommon. However, fatigue, loss of appetite, cognitive problems, numbness or tingling in the hands and feet, and even feeling depressed or irritable, all can occur when B12 blood levels fall,\u201d the hematologist says.Dr. Varki continues that while measuring serum levels of Vitamin B12 is not part of the annual physical examination for people who don\u2019t have risk factors for a deficiency, blood work is a key component of the evaluation when a patient has symptoms suggestive of the condition.\u201cLet\u2019s say that a patient sees his or her primary care physician and reports experiencing fatigue. That is a relatively common complaint, and one that can be the result of a great number of conditions, some more serious than others. The physician will start by taking a thorough history. Factors such as having Crohn\u2019s disease or ulcerative colitis, significant alcohol use, or following a vegetarian diet would focus the physician\u2019s attention on a potential deficiency of Vitamin B12, along with several other possible causes,\u201d Dr. Varki notes.The hematologist adds that the physician would ask about other symptoms that might suggest inadequate levels of B12 and perform a physical examination to look for signs of that condition or other disorders. Initial blood tests would include a complete blood count (CBC) and measurement of serum levels of B12 and folate, also known as Vitamin B9, which has many functions similar to those of B12. Dr. Varki notes, \u201cWhen there is a significant Vitamin B12 deficiency, the CBC often will show large, structurally abnormal, under-developed red blood cells, which is known medically as megaloblastic anemia.\u201dDr. Horkheimer says that once Vitamin B12 deficiency is identified, the focus turns to addressing underlying causes, when possible, and to providing treatment to help the patient achieve adequate levels of the vitamin.\u201cSome underlying causes can be modified, such as reducing alcohol use, increasing intake of food containing Vitamin B12, and perhaps changing prescriptions when a particular medication interferes with absorption of the vitamin. Daily high-dose oral supplements also can help correct a mild deficiency or one driven by diet. However, other causes, such as pernicious anemia, cannot be corrected,\u201d he says.\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\u201cCorrecting Vitamin B12 deficiency is important to avoid potential problems including fatigue, neurological issues, heart palpitations, and low counts of the red blood cells that carry oxygen and the white blood cells that fight infection.\u201d\u2028\u2028\t\t\t\t\t\t\t\t- Vinod Varki, MD\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\u201cVitamin B12 deficiency is an under-appreciated condition, and, unfortunately, often can be a significant health concern, but it also is eminently treatable.\u201d\u2028\u2028\t\t\t\t\t\t\t\t- Ian Horkheimer, MD\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tWhen to See a Hematologist About Vitamin B12 DeficiencyDr. Horkheimer adds that while primary care physicians can manage many cases of Vitamin B12 deficiency, referral to a hematologist can be indicated in certain situations, such as when:the results of blood tests to identify the condition are unclear;the deficiency is the result of significant malabsorption;the deficiency is severe;there are worrisome symptoms; or,the patient has a complex medical history, such as the presence of other serious conditions.\u201cIntramuscular injections of Vitamin B12 are at the core of our typical management plan for a significant deficiency,\u201d Dr. Horkheimer says. He explains that this route of administration is favored when patients have gastrointestinal absorption issues and so are not good candidates for oral medications that need to pass through the stomach and intestines. He adds that the shots generally are given once a week initially to help restore vitamin levels, followed by a move to monthly maintenance injections.\u201cWe individualize the injection schedule and other aspects of our care to best address each patient\u2019s particular situation and needs,\u201d Dr. Horkheimer says, adding that RCCA\u2019s management of Vitamin B12 deficiency also includes extensive patient education, attention to related risk factors and conditions, close monitoring, and communication and collaboration with the patient\u2019s other physicians.\u201cVitamin B12 deficiency is an under-appreciated condition, and, unfortunately, often can be a significant health concern, but it also is eminently treatable,\u201d says Dr. Horkheimer. He adds, \u201cSuccessful management starts with talking with your primary care physician promptly when you are experiencing fatigue or other concerning symptoms and then working in partnership with your care team in terms of any indicated lifestyle changes or medical treatments.\u201dFind Expert Hematology Care Near You in NJ, CT, MA, and the Washington, D.C., Area Dr. Varki and Dr. Horkheimer are among 90+ medical oncologists and hematologists who practice with Regional Cancer Care Associates (RCCA), one of the nation\u2019s largest networks of oncology specialists. RCCA has more than 20 locations near you across New Jersey, Connecticut, Massachusetts, and the Washington, D.C., area. RCCA\u2019s cancer specialists see more than 30,000 new patients each year and provide care to more than 265,000 established patients, collaborating closely with those patients\u2019 other physicians. RCCA physicians offer patients innovative therapies, including immunotherapies and targeted therapy, as well as access to approximately 300\u00a0clinical trials. In addition to serving patients who have solid tumors, blood-based cancers, and benign blood disorders, RCCA care centers also provide\u00a0infusion services to people with a number of non-oncologic conditions\u2014including\u00a0multiple sclerosis,\u00a0Crohn\u2019s disease,\u00a0asthma, iron-deficiency anemia, and\u00a0rheumatoid arthritis\u2014who take intravenously-administered medications.To learn more about RCCA, call 844-346-7222 or contact RCCA. visit\u00a0RCCA.com.\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tReferencesAnkar A, Kumar A. Vitamin B12 deficiency. StatPearls. September 10, 2024. Available at https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK441923\/. Accessed June 17, 2026.Cleveland Clinic. Vitamin B12 deficiency. September 30, 205. Available at https:\/\/my.clevelandclinic.org\/health\/diseases\/22831-vitamin-b12-deficiency. Accessed June 18, 2026.National Institute of Health. Office of Dietary Supplements. Vitamin B12 Fact Sheet for Health Professionals. July 2, 2025. Available at https:\/\/ods.od.nih.gov\/factsheets\/VitaminB12-HealthProfessional\/#h26. Accessed June 17, 2026.Reider CA, Chung R-Y, Devarshi PP, Grant RW, Mitmesser SH. Inadequacy of immune health nutrients. Intakes in US adults, the 2005-2016 NHANES. Nutrients. 2020;12(6):1735. doi:\u00a010.3390\/nu12061735Shipton MJ, Thachil J. Vitamin B12 deficiency \u2013 a 21st Century perspective. Clin Med. 2015;15(2):145-150.\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\twe are here for you\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tFor more information or to schedule an appointment, call 844-346-7222. You can also schedule an appointment by calling the\u00a0RCCA location\u00a0nearest you.\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\trequest an appointment\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tRELATED ARTICLES\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\tHow Do Cancer Clinical Trials Work, and Who Qualifies to Participate?\t\t\t\t\t\t\t\t\t\t\t\tIf you’ve been diagnosed with cancer, you may be wondering about all the different treatment options available. 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