Ebook Vitamin B12: Are You Getting It?
The overwhelming consensus in the mainstream nutrition community, as well as among vegan health professionals, is that plant foods do not provide vitamin B12. Despite this, some vegan advocates still believe that plant foods provide all the nutrients necessary for optimal health and, therefore, do not address vitamin B12 when promoting the vegan diet. Other vegan advocates acknowledge the need for B12, but only as an afterthought. The result is that many vegans do not eat B12 fortified foods or supplements. Many have developed classic neurological symptoms of a B12 deficiency. In some cases, the symptoms have cleared up after taking B12 supplements, but not everyone has been so lucky.
While many current vegans report feeling better on a vegan diet, the most common complaint I hear from ex-vegans is that they didn’t feel healthy. This seems logical: The people who feel good on the diet stick with it. The people who feel bad, don’t. Could it be that some of the people who go back to eating animal products are feeling the effects of a reduced B12 status? Many vegans would not consider this a possibility, because humans need very little B12 and new vegans usually have a healthy store which can last months or years.
The fact that vegans tend to have lower B12 levels than lacto-ovo vegetarians or nonvegetarians is often countered with, “Few vegans have ever shown signs of B12 deficiency.” However, most vegans appear to supplement their diet with B12 (often unknowingly through fortified foods), which could explain why most vegans never show B12 deficiency. As for vegans whose diets are not supplemented, I disagree that they rarely show signs of B12 deficiency. As the reader will soon see, there have certainly been plenty of vegans who have suffered from B12 deficiency, and it is time that there were no more. Vegans can ensure optimal B12 status, reducing their risk for many diseases, by following the recommendations in Table 1.
This article is a thorough review of the scientific literature about vitamin B12 and the vegan diet, including every relevant study on vegans and vitamin B12 published since 1980. Recommendations are summarized in Table 1. Vegan advocates who may otherwise not be interested in the details of vitamin B12 are encouraged to read the Conclusion.
Contents
1. Introduction
2. Vitamin B12: A Pesky Molecule
- 2.1 The B12 Molecule
- 2.2.1 Digestion & Absorption of Protein-bound B12
2.2.2 Digestion & Absorption of Unbound B12
2.3 Enterohepatic Circulation
2.4 Transport in the Blood
2.5 Pernicious Anemia
3. Coenzyme Functions of Vitamin B12
- 3.1 Homocysteine Clearance
3.2 Anemia, DNA, and Folate
- 3.2.1 Macrocytic Anemia: Not an Adequate Measure of B12 Status
3.3 Methylmalonic Acid (MMA)
4. Serum B12 Level: Not a Reliable Measure of B12 Adequacy
- 4.1 Seaweeds Can Falsely Inflate sB12 Levels
4.2 Measuring Transcobalamin II
4.3 B12-Deficient Nerve Damage with Normal sB12 and No Macrocytosis
5. Symptoms of B12 Deficiency
- 5.1 Neurological Symptoms
5.2 Early, Noticeable Symptoms of B12 deficiency
5.3 Other symptoms of B12 deficiency
5.4 When is it Time to Call a Doctor?
5.5 Ways to Get B12 Deficiency
6. Unusually High B12
7. Sources of B12 for Vegans
- 7.1 Myth about How Often Someone Needs B12
7.2 Small Amounts of Animal Products.
7.3 Fortified Foods
- 7.3.1 Brewer’s and Nutritional Yeasts
7.3.2 Cooking Foods
7.4 Multivitamins
7.5 Supplements
- 7.5.1 Safety
7.5.2 Chew or Dissolve Supplements Under the Tongue
7.5.3 Light
7.5.4 Twinlab B12 Dots
7.5.5 Non-cyanocobalamin Supplements
7.6 Oral B12 for People with Malabsorption
8. The B12 Status of Vegans
- 8.1. Infants
- 8.1.1 Infants of Vegan Mothers Who Do Not Use B12
Supplements
8.1.2 Correction of B12 Deficiency in Infants
8.1.3 Black Hebrews
8.1.4 Vegan Infants Taking B12 Supplements
8.2 Children & Teenagers
- 8.2.1 Vegan Children & Teenagers Not Supplementing with B12
8.2.2 Vegan Children & Teenagers Supplementing with B12
8.3 Adult Vegans
- 8.3.1 Studies on Adult Vegans Not Supplementing with B12
8.3.2 Vegans Taking B12 Supplements
8.4 Elderly Vegetarians & Vegans
8.5 Raw Foodist Vegans
9. Lacto-ovo Vegetarians (LOV)
10. Macrobiotics
11. Vegans, B12, Homocysteine & Disease
- 11.1 Background on Homocysteine
11.2 Studies on Homocysteine in Vegans and Vegetarians not
Supplementing with B12
11.3 Conclusion
12. B12 & Cancer
- 12.1 B12 & Breast Cancer
13. Measuring B12 in Plant Foods: Why the Confusion?
- 13.1 Microbiological Assay
13.2 Radioassay
13.3 Ochromonas malhamensis Fares Better than an Intrinsic Factor Assay
13.4 Paper Chromatography
13.5 Methylmalonic Acid Reduction: The Gold Standard
14. Are Intestinal Bacteria a Source of B12?
- 14.1 Bacteria in the Large Intestine
14.2 Bacteria in the Small Intestine
14.3 Conclusion
15. Organic Produce & Soil as a B12 Source for Vegans
- 15.1 B12 Analogue-Producing Bacteria in the Soil
15.2 Organic Produce Using Human Manure as Fertilizer
15.3 Organic Produce Using Cow Manure as Fertilizer
- 15.3.1 Soybean Plants Absorb B12 when Added to the Soil
15.3.2 Plants Absorb B12 Analogue when Added to the Soil via Cow Dung
16. B12 in Non-Human Animals
17. Immerman: The Exception
18. Conclusion
- 18.1 Can a Natural Diet Require Supplements?
18.2 The Medical Community: Future of Research on Vegans
18.3 Encourage New Vegans to Concern Themselves with B12 Supplements
18.4 Daily or Weekly Supplementation?
Appendix A. B12 Analogue in Tempeh, Seaweeds, and Other Plant Foods
A.1 Foods with No Detectable Amount of B12 Analogue
A.2 Foods with Detectable B12 Analogue in Some Studies
A.3 Tempeh
A.4 Seaweeds
- A.4.1 Various Seaweeds: Dulce Warrants Further Study
A.4.2 Aphanizomenon flos-aquae
A.4.3 Chlorella
A.4.4 Spirulina
A.4.5 Nori
A.4.6 Coccolithophorid Algae
A.5 Plant Sources of B12 Analogues Studied in Humans
A.6 Conclusion
Appendix B. Slightly Elevated MMA Levels
Appendix C. Vegan Mothers’ Infants & Toddlers with Serious
B12 Deficiency
Appendix D. B12 Levels in Lacto-ovo Vegetarians
Appendix E. Vegan or Vegetarian Children with Serious B12
Deficiency
Appendix F. B12 Levels in Macrobiotics
Appendix G. Note about Twinlab B12 Dots
Appendix H. Inactive Analogues: Worse than Useless
Appendix I. Homocysteine & Disease
I.1 Background
- I.1.1 Measuring Homocysteine
I.1.2 Vitamin Supplementation Can Confound Study Results
I.2 Homocysteine & Cardiovascular Disease
- I.2.1 Recent Reviews of the Studies on Elevated Homocysteine and CVD
I.2.2 Prospective Studies on Homocysteine and Cardiovascular Disease
I.2.3 Treatment of High Homocysteine with Folate, B12, & B6 in Nonvegetarians
- I.2.3.1 Reduced Plaque in Carotid Arteries
I.2.3.2 Improved Exercise Test, Ankle-brachial Pressure, and Arterial Stenosis
I.2.3.3 Improved Endothelial Function
I.2.4 Elevated sB12 as an Increased Risk Factor for Disease
I.3 B12, Homocysteine, & Alzheimer’s Disease
I.4 B12, Folate, Homocysteine, & Age-Related Hearing Loss
I.5 B12, Folate, Homocysteine, & Birth Defects
I.6 Homocysteine and Recurrent Early Pregnancy Loss
I.7 Homocysteine and Mortality
I.8 Homocysteine & Kidney Disease
I.9 Low Methionine Intakes May Exacerbate High Homocysteine
Levels in B12 Depleted States
I.10 One Week of Vegan Diet (with B12) & Other Lifestyle
Changes Lowers Homocysteine
Appendix J. Homocysteine & Kidney Disease
Appendix K. Ways to Get B12 Deficiency
Appendix L. Formulation of Recommendations
L.1 Step 1.
L.1.1 Oral B12 for People with Malabsorption
L.2 Step 2 Recommendations.
- L.2.1 Absorption Rates of B12
L.2.2 What is a healthy B12 Level?
L.2.3 What Intake is Needed to Achieve a Healthy Level?
L.2.4 Recommendations
Appendix M. People Who Should Not Take the Cyanocobalamin
Form of B12
M.1 Cyanide Metabolism Defects
M.2 Chronic Kidney Failure
Appendix N. Non-cyanocobalamin B12 Supplements
N.1 Methylcobalamin in a Small Sample of Vegans
N.2 Therapeutic Use of Coenzyme form of B12
N.3 Hydroxocobalamin
N.4 SAMe
Appendix O. Smokers and Cyanocobalamin
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