Too much or too little B12 can be risky for diabetics
Associations of Serum Folate and Vitamin B12 Levels With Cardiovascular Disease Mortality Among Patients With Type 2 Diabetes
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
High B12 levels carried a higher risk (132%) than low B12 levels (74%) — making excess more dangerous than deficiency.
Everyone assumes deficiency is the problem. This study shows that in diabetics, the highest mortality risk came from the top end of B12 levels — contradicting the common 'more is better' supplement culture.
Practical Takeaways
If you have type 2 diabetes, ask your doctor for a serum B12 test — and don’t assume you need supplements. If your level is above 700 pg/mL, investigate why instead of taking more.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
High B12 levels carried a higher risk (132%) than low B12 levels (74%) — making excess more dangerous than deficiency.
Everyone assumes deficiency is the problem. This study shows that in diabetics, the highest mortality risk came from the top end of B12 levels — contradicting the common 'more is better' supplement culture.
Practical Takeaways
If you have type 2 diabetes, ask your doctor for a serum B12 test — and don’t assume you need supplements. If your level is above 700 pg/mL, investigate why instead of taking more.
Publication
Journal
JAMA Network Open
Year
2022
Authors
Yujie Liu, T. Geng, Z. Wan, Qi Lu, Xuena Zhang, Zixin Qiu, Lin Li, Kai Zhu, Liegang Liu, A. Pan, Gang Liu
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Claims (6)
In people with type 2 diabetes, having very high levels of vitamin B12 in the blood seems to be linked to a much higher chance of dying from heart disease—higher than at any other B12 level—so maybe high B12 isn’t helping, but instead signals something else wrong in the body.
For people with type 2 diabetes, having higher levels of folate (a B vitamin) in their blood doesn’t seem to make them more likely to die from heart disease, compared to people with moderate folate levels.
People with type 2 diabetes who have low levels of folate (a B vitamin) in their blood are 43% more likely to die from heart disease than those with moderate folate levels—so low folate might be linked to worse heart outcomes.
For people with type 2 diabetes, having too little or too much vitamin B12 in the blood might increase the chance of dying from heart disease — the safest range seems to be in the middle.
If your blood has too little or too much vitamin B12, you might be at higher risk of dying from any cause or from heart disease — the safest range is in the middle, between 190 and 948 pg/mL.