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- Vitamin B12 Deficiency Anemia
Content Map Terms
Healthy Eating & Physical Activity Categories
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Active for Health
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Age and Stage
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Infants, Children and Youth
- Child Who Is Overweight: Evaluating Nutrition and Activity Patterns
- Child Who Is Overweight: Medical Evaluation
- Eczema and Food Allergy in Babies and Young Children
- Feeding Your Baby: Sample Meals for Babies 6 to 12 Months of Age
- Finger Foods for Babies 6 - 12 Months
- Food Allergy Testing
- HealthLink BC Eating and Activity Program for Kids
- Healthy Eating for Children
- Healthy Eating Guidelines for Your Vegetarian Baby: 6-12 months
- Healthy Eating Guidelines for Your Vegetarian Toddler: 1-3 years
- Helping Your Child Who Is Overweight
- Interactive Tool: What Is Your Child's BMI?
- Iron-Fortified Infant Cereal Recipes: Finger Foods For Babies and Toddlers
- Making Family Meals Enjoyable
- Mealtime and Your Toddler
- Parenting Babies (0-12 months)
- Recipes for Your Baby 6 - 9 Months Old
- Recipes for Your Baby 9 - 12 Months Old
- Reducing Risk of Food Allergy in Your Baby
- Snack Ideas for Preschoolers
- Specialized Formula Shortage
- Vitamins and Minerals for Toddlers
- Your Toddler: Nutritious Meals for Picky Eaters
- Physical Activity for Infants, Children and Youth
- Older Adults
- Pregnancy
- Menopause and Perimenopause
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Infants, Children and Youth
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Being Active
- Health Benefits of Physical Activity
- Myths About Physical Activity
- SMART Goal Setting
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Getting Started
- Getting Started: Adding More Physical Activity to Your Life
- Quick Tips: Fitting Physical Activity Into Your Day
- Quick Tips: Getting Active as a Family
- Fitness: Adding More Activity To Your Life
- Getting Started With Flexibility and Exercise
- Fitness Machines
- Fitness Clothing and Gear
- Be Active: Move to Feel Good
- The Three Kinds of Fitness
- Set SMART Goals
- Overcoming Barriers: Adding More Physical Activity to your Life
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Choosing Your Activity
- How to Choose Safe Equipment
- Exercising While Sitting Down
- Fitness DVDs and Videos
- Tips for Picking the Right Activities
- Quick Tips: Getting in Shape Without Spending Money
- Fitness: Walking for Wellness
- Walk Your Way To Health
- Tai Chi and Qi Gong
- Water Exercise
- Yoga
- Bob's Story: Biking for Health
- Exercise and Physical Activity Ideas
- Fitness: Choosing Activities That Are Right for You
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Staying Active
- Fitness: Getting and Staying Active
- Fitness: Making It a Habit
- Quick Tips: Having Enough Energy to Stay Active
- Quick Tips: Staying Active at Home
- Quick Tips: Staying Active When You Travel
- Physical Activity in Winter
- Quick Tips: Staying Active in Cold Weather
- Quick Tips: Staying Active in Hot Weather
- Injury Prevention and Recovery
- Fitness and Exercise Learning Centre
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Conditions
- Diabetes and Hypoglycemia
- Eating Disorders
- Healthy Eating for Disease Prevention
- Eating Right When You Have More Than One Health Problem
- Being Active When You Have More Than One Health Problem
- Physical Activity and Disease Prevention
- Anemia
- Arthritis and Osteoporosis
- Physiotherapy for Low Back Pain
- Low Back Pain: Exercises to Reduce Pain
- Cancer
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Digestive
- Managing Constipation in Adults
- Healthy Eating Guidelines for People with Diverticular Disease
- Fibre and Your Health
- Lower Fibre Food Choices
- Eating Guidelines For Gallbladder Disease
- Healthy Eating Guidelines for Irritable Bowel Syndrome
- Lactose Intolerance
- Healthy Eating Guidelines for People with Peptic Ulcers
- Bowel Disease: Changing Your Diet
- Celiac Disease: Eating a Gluten-Free Diet
- GERD: Controlling Heartburn by Changing Your Habits
- Irritable Bowel Syndrome: Controlling Symptoms with Diet
- Food Allergies
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Heart
- Cardiac Rehabilitation
- Coronary Artery Disease: Exercising for a Healthy Heart
- DASH Diet Sample Menu
- Healthy Eating Guidelines for People Taking Warfarin Anticoagulants
- Healthy Eating to Lower High Blood Pressure
- Exercising to Prevent a Stroke
- Healthy Diet Guidelines for a Healthy Heart
- Heart Arrhythmias and Exercise
- Heart Failure: Eating a Healthy Diet
- Heart Failure: Track Your Weight, Food and Sodium
- Heart-Healthy Eating
- Heart-Healthy Eating: Fish
- Heart-Healthy Lifestyle
- High Blood Pressure: Nutrition Tips
- High Cholesterol: How a Dietitian Can Help
- Modify Recipes for a Heart-Healthy Diet
- Plant-based Diet Guidelines
- Peripheral Arterial Disease and Exercise
- Physical Activity Helps Prevent a Heart Attack and Stroke
- High Blood Pressure: Using the DASH Diet
- Healthy Eating: Eating Heart-Healthy Foods
- Heart Health: Walking for a Healthy Heart
- Izzy's Story: Living with the DASH Diet
- Exercise and Fibromyalgia
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Kidney and Liver
- Healthy Eating Guidelines for People with Early Chronic Kidney Disease (CKD) Stages 1 and 2
- Healthy Eating Guidelines for Prevention of Recurrent Kidney Stones
- Healthy Eating for Chronic Hepatitis
- Kidney Disease: Changing Your Diet
- Kidney Stones: Preventing Kidney Stones Through Diet
- Non-Alcoholic Steatohepatitis (NASH)
- Lupus: Healthy Eating
- Mutiple Sclerosis
- Parkinson's Disease and Exercise
- Sally's Story: Avoiding Metabolic Syndrome
- Spinal Cord
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Food and Nutrition
- About Healthy Eating
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Eating Habits
- Developing a Plan for Healthy Eating
- Drinking Enough Water
- Eating Healthy at Holiday Parties
- Eating Journal
- Emotional Eating
- Encourage Healthy Eating Away From Home
- Food Journaling: How to Keep Track of What You Eat
- Healthy Eating: Changing Your Eating Habits
- Healthy Eating: Getting Support When Changing Your Eating Habits
- Healthy Eating: Making Healthy Choices When You Eat Out
- Healthy Eating: Making Healthy Choices When You Shop
- Healthy Eating: Overcoming Barriers to Change
- Healthy Eating: Starting a Plan for Change
- Healthy Eating: Staying With Your Plan
- Healthy Eating to Decrease Stress
- Jaci's Story: Changing her Life With Small Steps
- Jeremy's Story: Focusing on Eating Habits
- Loralie's Story: It's Never Too Late
- Maggie Morries: Plan Ahead When You Eat Out
- Plant-based Foods
- Sugary Drinks and Other Beverages
- Sodium
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Nutrients
- Added Sugars
- Antioxidants
- Antioxidants and Your Diet
- Carbohydrate Foods
- Carbohydrate, Proteins, Fats and Blood Sugar
- Choosing a Vitamin and Mineral Supplements
- Cholesterol and Triglycerides: Eating Fish and Fish Oil
- Comparing Sugar Substitute
- Dietary Fats and Your Health
- Dietary Guidelines for Good Health
- Dietary Reference Intake
- Eating Protein
- Calcium and Your Health
- Food Sources of Vitamin K
- Getting Enough Calcium and Vitamin D
- Getting Enough Fibre
- Getting Enough Folic Acid
- Getting Enough Iron
- Getting Enough Potassium
- Healthy Eating: Cutting Unhealthy Fats From Your Diet
- Healthy Eating: Taking Calcium and Vitamin D
- High Potassium Eating
- High Potassium Foods
- Iron and Your Health
- Iron in Foods
- Low-Potassium Foods
- Major Nutrients in Food
- Minerals: Their Functions and Sources
- Non-Milk Sources of Calcium
- Quick Nutrition Check for Protein
- Quick Nutrition Check for Protein: Sample Menus
- Quick Nutrition Check for Vitamin B12
- Types of Fats
- Vitamin and Mineral Supplements for Adults
- Vitamins: Their Functions and Sources
- Food Labels
- Healthy Eating and Nutrition Topics A-Z
- Plan, Shop and Prepare
- Food, Water and Beverage Safety
- Canada's Food Guide FAQs
- Food Security
- Vegetarian Diets
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Healthy Weights
- About Healthy Weights
- Genetic Influences on Weight
- Screening for Weight Problems
- Unplanned Weight Loss
- Quick Tips: Cutting Calories
- Physical Activity for Weight Loss
- Weight Loss by Limiting Calories
- Tips for Maintaining Weight Loss
- Choosing a Weight-Loss Program
- Boosting Your Metabolism
- Exercise Helps Maggie Stay at a Healthy Weight
- Healthy Eating: Recognizing Your Hunger Signals
- Hunger, Fullness, and Appetite Signals
- Weight Management
- Weight Management: Stop Negative Thoughts
- Maggie's Strategies for Eating Healthy
- Maggie: Making Room for Worth-It Foods
- Maggie's Story: Making Changes for Her Health
- Weight Management Centre
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Policies and Guidelines
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Guidelines for Food and Beverage Sales in BC Schools
- Guidelines for Food and Beverage Sales: Making Bake Sales Delicious and Nutritious
- Guidelines for Food and Beverage Sales: Boosting the Sales of Nutritious Food in Schools
- Guidelines for Food and Beverage Sales: Food Fundraiser Ideas for Schools
- Guidelines for Food and Beverage Sales: Involving Everyone in Implementing the Guidelines
- Guidelines for Food and Beverage Sales: Selling Food and Beverages at School Sporting Events
- Guidelines for Food and Beverage Sales: Planning Healthy Cafeteria Menus
- Healthier Choices in Vending Machines
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Guidelines for Food and Beverage Sales in BC Schools
- Provincial Nutrition Resource Inventory
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Forms and Tools
- Walking Log
- Exercise Planning Form
- Physical Activity Log
- Par-Q+ and ePARmed-X+
- Target Heart Rate
- Interactive Tool: What is Your Target Heart Rate
- Borg-Rating of Perceived Exertion Scale
- Rating of Perceived Exertion (RPE)
- Heart Rate Calculator
- Overview of BC Provincial and Federal Nutrition Benefits Programs
- Body Mass Index (BMI)
- Body Mass Index (BMI) for Adults
- Interactive Tool: Do Your BMI and Waist Size Increase Your Health Risks?
- Measuring Your Waist
- Estimating Body Fat Percentage
- Factsheet Generator
- Fitness: Using a Pedometer or Step Counter
- Email a HealthLinkBC Dietitian
- Email a Qualified Exercise Professional
British Columbia Specific Information
For detailed information on food sources of vitamin B12, see Quick Nutrition Check for Vitamin B12.
Topic Contents
Condition Basics
What is vitamin B12 deficiency anemia?
Having vitamin B12 deficiency means that your body does not have enough of this vitamin. You need B12 to make red blood cells, which carry oxygen through your body. Not having enough B12 can lead to anemia, which means your body does not have enough red blood cells to do the job. This can make you feel weak and tired. Vitamin B12 deficiency can cause damage to your nerves and can affect memory and thinking.
What causes it?
Most people get more than enough B12 from eating meat, eggs, milk, and cheese. Normally, the vitamin is absorbed by your digestive system—your stomach and intestines. Vitamin B12 deficiency anemia usually happens when the digestive system is not able to absorb the vitamin. This can happen if:
- You have pernicious anemia. In this anemia, your body destroys the cells in your stomach that help you absorb vitamin B12.
- You have had surgery to remove part of the stomach or the last part of your small intestine, called the ileum. This includes some types of surgery used to help very overweight people lose weight.
- You have problems with the way your body digests food, such as sprue (also called celiac disease), Crohn's disease, bacteria growth in the small intestine, or a parasite.
This anemia can also happen if you don't eat enough foods with B12, but this is rare. People who eat a vegan diet and older adults who don't eat a variety of foods may need to take a daily vitamin pill to get enough B12. Other causes include drinking alcohol and taking some prescription and non-prescription medicines.
Recommended amounts of vitamin B12
The amount of vitamin B12 you need each day depends on your age. footnote 1
- Age 1 to 3 years: 0.9 micrograms (mcg) a day
- Age 4 to 8 years: 1.2 mcg
- Age 9 to 13 years: 1.8 mcg
- Age 14 and older: 2.4 mcg
- During pregnancy: 2.6 mcg
- While breastfeeding: 2.8 mcg
What are the symptoms?
If your vitamin B12 deficiency is mild, you may not have symptoms or you may not notice them. Some people may think the symptoms are just the result of growing older. As the anemia gets worse, you may:
- Feel weak, tired, and light-headed.
- Have pale skin.
- Have a sore, red tongue or bleeding gums.
- Feel sick to your stomach and lose weight.
- Have diarrhea or constipation.
If the level of vitamin B12 stays low for a long time, it can damage your nerve cells. If this happens, you may have:
- Numbness or tingling in your fingers and toes.
- A poor sense of balance.
- Depression.
- A decrease in mental abilities.
How is it diagnosed?
Your doctor will examine you and ask questions about your past health and how you are feeling now. You will also have blood tests to check the number of red blood cells and to see if your body has enough vitamin B12.
The level of folate, another B vitamin, will be checked too. Some people whose vitamin B12 levels are too low also have low levels of folate. The two problems can cause similar symptoms. But they are treated differently.
How is vitamin B12 deficiency anemia treated?
Vitamin B12 deficiency anemia is treated with supplements of vitamin B12. Taking supplements brings your level of vitamin B12 back to normal, so you do not have symptoms. To keep your level of vitamin B12 normal, you will probably need to take supplements for the rest of your life. If you stop taking them, you'll get anemia again.
Your vitamin B12 supplements might be pills or shots. If you use shots, you can learn to give them to yourself at home. For many people, pills work just as well as shots. They also cost less and are easier to take. If you have been getting shots, ask your doctor if you can switch to pills.
You can take steps at home to improve your health by eating a varied diet that includes meat, milk, cheese, and eggs, which are good sources of vitamin B12. Also, eat plenty of foods that contain folate (or folic acid), another type of B vitamin. These include leafy green vegetables, citrus fruits, and breads and cereals that are fortified with folic acid.
How can you prevent it?
Most people who eat animal products like milk, cheese, and eggs will not get this B12 deficiency anemia. People who follow a vegan diet can prevent it by taking a daily vitamin pill or by eating foods that have been fortified with B12.
Babies born to women who eat a vegan diet should be checked by a doctor to see whether they need extra vitamin B12.
If you have pernicious anemia or another reason you cannot absorb enough vitamin B12, your doctor will give you vitamin B12 shots or pills to prevent deficiency.
Foods that contain vitamin B12
Vitamin B12 is found in foods from animals, such as meat, seafood, milk products, poultry, and eggs. It is not in foods from plants unless it has been added to the food (fortified). Some foods are fortified with vitamin B12.
Supplements containing only B12, or B12 along with other B vitamins and/or folic acid, are readily available. Also, B12 is usually in multivitamins. Check the label to find out how much B12 is in a supplement.
Food |
Serving size |
B12 amount (micrograms) |
---|---|---|
Lamb kidney |
75 grams (2½ ounces) |
59 mcg |
Clams |
75 grams (2½ ounces) |
15 mcg |
Salmon |
75 grams (2½ ounces) |
4 mcg |
Large egg |
2 eggs |
1.5 mcg |
Non-fat plain yogurt |
175 g (¾ cup) |
0.3–0.5 mcg |
Turkey |
75 grams (2½ ounces) |
0.2–1.0 mcg |
Related Information
References
Citations
- Food and Nutrition Board, Institute of Medicine (2011). Dietary reference intakes (DRIs): Recommended dietary allowances and adequate intakes, vitamins. Available online: http://iom.edu/Activities/Nutrition/SummaryDRIs/~/media/Files/Activity%20Files/Nutrition/DRIs/New%20Material/2_%20RDA%20and%20A….
- Dietitians of Canada (2020). Food sources of vitamin B12. Dietitians of Canada. https://www.pennutrition.com/KnowledgePathway.aspx?kpid=2709&trid=28019&trcatid=467. Accessed September 22, 2021.
Credits
Current as of: November 29, 2021
Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD - Internal Medicine
Martin J. Gabica MD - Family Medicine
Adam Husney MD - Family Medicine
Current as of: November 29, 2021
Author: Healthwise Staff
Medical Review:E. Gregory Thompson MD - Internal Medicine & Martin J. Gabica MD - Family Medicine & Adam Husney MD - Family Medicine
This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use and Privacy Policy. Learn how we develop our content.
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