B12 overdose / megadose?

[velphick]

[Hi! Your post has been moved the section for not-yet-vegans, here: http://www.veganforum.com/forums/showthread.php?30325-From-another-thread-B12-overdose-megadose. Korn.]

[Korn]

High plasmatic concentration of vitamin B12: An indicator of hepatic diseases or tumors (http://www.ncbi.nlm.nih.gov/pubmed/23142127) PMID: 23142127

http://www.ncbi.nlm.nih.gov/pubmed/23142127


PURPOSE:
To identify the diseases that are associated with a high plasma concentration of vitamin B12 and to measure the strength of this association.

PATIENTS AND METHODS:
Retrospective study including all admissions between 1st May, 2005 and 30th April, 2008 in the UMAG pole departments (emergency, internal medicine, acute geriatrics and medical intensive care) with a test for plasma vitamin B12. The association between each of medical information system codes (solid tumors, malignant hematologic process, and renal disease) and a high or low vitamin B12 concentration was measured by odds ratios (OR) from logistic models taking into account repeated admissions, with adjustment for age and the weighted Charlson index.

RESULTS:
Among 3702 admissions, 12% had a B12 more than 820pg/ml, 10.4% a B12 less than 180pg/ml and 77.6% a normalB12 concentration. After adjustment for age and the weighted Charlson index, high concentration of vitamin B12 was associated with interstitial renal diseases (OR 2.7; 95% CI: [1.7-4.2]), and cirrhosis or hepatitis (OR 4.3; [2.9-6.4]). After additional adjustment for these parameters, it was still associated with tumors (OR 1.8; [1.2-2.6]), malignant hematologic diseases (OR 2.1; [1.3-3.5]), metastasis (OR 2.9; [1.5-5.9]), liver metastasis (OR 6.2; [2.7-14.5]), liver carcinoma (LC) (OR 3.3; [1.1-10.4]), liver tumors other than LC (OR 4.7; [1.2-17.9]) and lymphoma (OR 3.2; [1.6-6.4]) but not with myeloma (OR 1.9; [0.6-1.4]). Low concentration of B12 was associated with myeloma (OR 2.9; [1.3-6.6]).

CONCLUSION:
Finding a high plasma concentration of vitamin B12 should lead to a systematic search for a hepatic disease or a tumor, and particularly for a hepatic localization of a tumor.


Such findings don't necessarily reveal what's cause and what's effect in contexts like these.

[Korn]

There's a link between high amount of B12 and some types of cancer.
B12 is essential for growth and cell division.
Cancer =uncontrolled growth/cell division.
There's also a link between high intake of animal products and cancer (animal products generally contain more B12 than plants, which normally contain low or no B12).

Based on this info, and the assumption that too high levels of B12 both causes exaggerated growth (represented as body height) and exaggerated cell division / cell growth / cancer, I have assumed that there would be a link between body height and cancer.

After googling cancer and height, I found this:

http://www.bmj.com/cgi/content/full/317/7169/0/d


http://www.aicr.org/site/News2?abbr=pr_&page=NewsArticle&id=12899


http://news.bbc.co.uk/1/hi/health/941890.stm

Here's another one, posted today on medicalnewstoday.com:
The taller the woman, the higher her cancer risk (http://www.medicalnewstoday.com/articles/264000.php)

According to the study, the taller a woman's stature is, the higher her risk of cancer at a number of different sites, including breast, colon, endometrium, kidney, ovary, rectum and thyroid. Additionally, taller women have a greater risk of developing multiple myeloma and melanoma.

All of these associations did not change after adjusting for known influencers of these cancers, such as age, weight, education, smoking habits, alcohol intake and hormone therapy. The researchers say that height even had more influence over cancer risk than a common measure of obesity, body mass index (BMI).

Researchers studied 144,701 women aged 50 to 79 who participated in the Women's Health Initiative from 1993 to 1998. After a follow-up 12 years later, in total, 20,928 cancers were identified within the group.

Results showed that for every 10-centimeter increase in height (3.94 inches), there was a 13% increase in likelihood of developing cancer.

Specifically:

An increase in risk of 13-17% for breast, ovary, endometrium and colon cancers, as well as for melanoma, and
An increase in risk of 23-29% for kidney, rectum, thyroid and blood cancers.

[Korn]

High B12 levels and increased cancer risk (http://www.veganforum.com/forums/showthread.php?16897-High-B12-levels-and-increased-cancer-risk)
The above link is of course relevant when it comes to discussing the risks involved in B12 overdosing. It has long been known that too low B12 levels is a bad thing in terms of cancer risk, but the studies referred to in the above thread also discusses potential risks involved in too high B12 levels. As vegans, the main focus for most of course will of course be to get enough B12, not the risk of getting too much of it, unlike we consume very high levels of B12 in supplements.

[Korn]

All vegans should know that it's important to get enough B12, but nevertheless - here are, again, some (old and new) links about possible risks involved with B12 megadoses.


http://vitamins.lovetoknow.com/Side_Effects_of_Too_Much_Vitamin_B12

http://www.mayoclinic.org/drugs-supplements/vitamin-b12/safety/hrb-20060243

http://vitamins.lovetoknow.com/Vitamin_B_12_Side_Effects

http://www.livestrong.com/article/26012-side-effects-much-b12/

http://vitamins.lovetoknow.com/Side_Effects_of_Too_Much_Vitamin_B12

http://b12hq.com/b12-warnings/

http://www.drugs.com/sfx/vitamin-b12-side-effects.html

http://www.usingvitaminswisely.com/vitamin-b12-overdose.html

http://www.ncbi.nlm.nih.gov/pubmed/15499634?dopt=Abstract

http://www.newhealthguide.org/Vitamin-B12-Overdose.html

[Korn]

Here are a couple of links from Nov 18 last year:
http://www.medicaldaily.com/high-levels-vitamin-b12-may-be-linked-increased-cancer-risk-263123

http://www.everydayhealth.com/cancer/study-vitaminb-correlated-with-higher-cancer-risk.aspx

[Korn]

From: http://www.ncbi.nlm.nih.gov/pubmed/25103858 [PMID:2510385]


When increased serum cobalamin concentrations are encountered clinically they are usually attributed to parenteral supplementation, dietary factors, or otherwise ignored. However, recently, hypercobalaminaemia has been associated with numerous diseases in humans, most notably neoplastic and hepatic disorders. The aim of this retrospective, observational, cross-sectional study was to determine the significance of increased cobalamin in cats.
RESULTS:In total, 237 records were retrieved and 174 cats, of various ages and sexes met the inclusion criteria. A total of 42 cats had increased serum cobalamin concentration, and had not received prior supplementation. Multiple logistic regression analysis revealed that increased serum cobalamin concentration was positively related to pedigree breed (pedigree breeds more likely to have increased cobalamin concentration, odds ratio [OR] 4.24, 95% CI 1.78-10.15, P = 0.001), to having liver disease (OR 9.91, 95% CI 3.54-27.68), and to having a solid neoplasm (OR 8.54, 95% CI 1.10-66.45).
CONCLUSIONS:The results of the current study suggest that increased serum cobalamin concentrations should not be ignored in cats with no history of supplementation, and investigation for underlying hepatic or neoplastic disease is warranted.

[Korn]

"In this review, we summarise known associations between high plasma cobalamin and diseases. We report associations mainly with cancer, liver and kidney diseases, but also with a number of other diagnostic entities. "
http://www.degruyter.com/view/j/cclm.2013.51.issue-3/cclm-2012-0545/cclm-2012-0545.xml (http://www.degruyter.com/view/j/cclm.2013.51.issue-3/cclm-2012-0545/cclm-2012-0545.xml)

[Korn]

"an abnormally high serum cobalamin level forms a warning sign requiring exclusion of a number of serious underlying pathologies. "

http://www.ncbi.nlm.nih.gov/pubmed/23447660 (http://www.ncbi.nlm.nih.gov/pubmed/23447660)


Hypercobalaminemia (high serum vitamin B12 levels) is a frequent and underestimated anomaly. Clinically, it can be paradoxically accompanied by signs of deficiency, reflecting a functional deficiency linked to qualitative abnormalities, which are related to defects in tissue uptake and action of vitamin B12. The aetiological profile of high serum cobalamin predominantly encompasses severe disease entities for which early diagnosis is critical for prognosis. These entities are essentially comprised of solid neoplasms, haematological malignancies and liver and kidney diseases. This review reflects the potential importance of the vitamin B12 assay as an early diagnostic marker of these diseases. A codified approach is needed to determine the potential indications of a search for high serum cobalamin and the practical clinical strategy to adopt upon discovery of elevated cobalamin levels. While low serum cobalamin levels do not necessarily imply deficiency, an abnormally high serum cobalamin level forms a warning sign requiring exclusion of a number of serious underlying pathologies. Functional cobalamin deficiency can thus occur at any serum level.



PMID:23447660

[Korn]

A returning topic in articles about associations between high B12 levels and disease is the fact that it's not an obvious relationship between cause and effect. Liver diseases, may for instance, cause "cobalamin release" (that B12 is released from the liver), as mentioned in this abstract:

http://www.ncbi.nlm.nih.gov/pubmed/11913109

[Korn]

"Although the pathologies associated with vitamin B12 deficiency are well known, hypervitaminemic B12 status is often fortuitous and frequent finding."
http://www.ncbi.nlm.nih.gov/pubmed/23185929 (http://www.ncbi.nlm.nih.gov/pubmed/23185929)

[Korn]

In this article, it is stated that "A number of diagnoses were significantly associated to very high Cbl levels (odds ratio (95% confidence interval)): alcoholism (5.74 (2.76-11.96)), liver disease (8.53 (3.59-20.23)), and cancer (5.48 (2.85-10.55))." The liver disease cases may at least partially be explained by the fact that B12 is released from the liver, and I guess it's quite obvious that high B12 levels doesn't cause alcoholism. But in addition, cancer (and patients with renal-, autoimmune-, and bronchopulmonary disease) are mentioned.

http://www.ncbi.nlm.nih.gov/pubmed/23029349

[PMID: 23029349]

[Korn]

Thus study, published in 2002, discusses the associations between high B12 levels and renal failure, elevated serum creatinine and diminished albumin.


http://www.ncbi.nlm.nih.gov/pubmed/11843883

PMID:11843883

[Korn]

High plasmatic concentration of vitamin B12: an indicator of hepatic diseases or tumors
To identify the diseases that are associated with a high plasma concentration of vitamin B12 and to measure the strength of this association.
PATIENTS AND METHODS:Retrospective study including all admissions between 1st May, 2005 and 30th April, 2008 in the UMAG pole departments (emergency, internal medicine, acute geriatrics and medical intensive care) with a test for plasma vitamin B12. The association between each of medical information system codes (solid tumors, malignant hematologic process, and renal disease) and a high or low vitamin B12 concentration was measured by odds ratios (OR) from logistic models taking into account repeated admissions, with adjustment for age and the weighted Charlson index.
RESULTS:Among 3702 admissions, 12% had a B12 more than 820pg/ml, 10.4% a B12 less than 180pg/ml and 77.6% a normal B12 concentration. After adjustment for age and the weighted Charlson index, high concentration of vitamin B12 was associated with interstitial renal diseases (OR 2.7; 95% CI: [1.7-4.2]), and cirrhosis or hepatitis (OR 4.3; [2.9-6.4]). After additional adjustment for these parameters, it was still associated with tumors (OR 1.8; [1.2-2.6]), malignant hematologic diseases (OR 2.1; [1.3-3.5]), metastasis (OR 2.9; [1.5-5.9]), liver metastasis (OR 6.2; [2.7-14.5]), liver carcinoma (LC) (OR 3.3; [1.1-10.4]), liver tumors other than LC (OR 4.7; [1.2-17.9]) and lymphoma (OR 3.2; [1.6-6.4]) but not with myeloma (OR 1.9; [0.6-1.4]). Low concentration of B12 was associated with myeloma (OR 2.9; [1.3-6.6]).
CONCLUSION:Finding a high plasma concentration of vitamin B12 should lead to a systematic search for a hepatic disease or a tumor, and particularly for a hepatic localization of a tumor.

http://www.ncbi.nlm.nih.gov/pubmed/23142127

PMID: 23142127