Do you want to know more about vitamin b12 absorption or why you have low b12? Maybe you have been diagnosed with b12 deficiency or you have symptoms that match b12 deficiency. If so the logical next question is “why are you low in b12 to being with.”
Absorption of b12 is a very common reason to have low b12. Let's look at the most common reasons people have vitamin b12 absorption issues, how to avoid them and also what you can do about it.
The 5 most common reasons to have b12 absorption issues.
- Coffee and caffeine
- Bacterial overgrowth and other digestive health issues
Coffee and Caffeine Affect B12 Absorption
Caffeine will increase the excretion of your B12 and other B vitamins. I have long been telling patients this but wanted to see if I could find research article supporting this. I did find a supporting article which you can read here.
This study looked at the circulating levels of b vitamins in healthy men and women coffee drinkers. They found that the people with the highest levels of B12, tended to deplete b vitamins most. Those with lower levels of circulating B vitamins did not excrete as much. So the affect of coffee on B vitamin excretion is more pronounced the higher your levels of B vitamins are starting from. There are other studies that found coffee drinkers tend to have higher homocysteine levels which is a surrogate marker for b12 (and folate) deficiency.
Overall it seems clear that coffee and caffeine increase excretion of B vitamins, including B 12.
Alcohol Affect on B12 Absorption
Similar to caffeine alcohol will increase the excretion of your b12 and other B vitamins. Alcohol is the most common reason to have lower b12 levels.
A study in nature showed that consumption of 1.5-3 drinks over the course of 8 weeks did decrease serum b12 levels by about 5 %. Here is the article related to alcohol and b12. .
Medication Affect on B12 Absorption
Many medications lower b12 levels by interfering with how b12 is absorbed. The main medications to be aware of are acid blocking and reducing medications like prilosec (omeprazole), ranitidine, zantac, Pepcid, nexium, etc.
By reducing the acid production b12 is not mobilized from food leading to lower absorption. Any time someone tells me they are taking one of these acid reducing medications, I check the b12 and ferritin levels. If they have been on these medications for more than 6 months they are typically low.
Digestive Affect on B12 Absorption
Many digestive problem can lead to reduced absorption or malabsorption of all kinds f vitamins and minerals but specifically b vitamins. B12 has to be released from the food you eat and is done by the enzymes and acids in the digestive tract. Once mobilized b12 needs help to be absorbed. A special transporter called intrinsic factor is needed for b12. Such a delicate process can easily be interrupted and often is.
Inflammation in the digestive cells will interfere with this process. Obvious digestive health problems like celiac’s Crohn’s, ulcerative colitis cause inflammation. Other less known causes of inflammation can also do this like bacterial overgrowth (SIBO), candida overgrowth, food sensitives, etc.
Genetic Affect on B12 Absorption
There are also several genetic alterations that can alter your b12 absorption. A SNP (single nucleotide polymorphism) known as FUT can both increase and decrease b12 absorption depending on which version of this SNP you have. The exact mechanism of how it changes b12 absorption is no clear but it is thought to be linked with both the prevalence of H. Pyloi infection and by default intrinsic factor production. Another genetic factor in b12 absorption is pernicious anemia. This is an autoimmune disorder where the body produces antibodies against intrinsic factor. This means the b12 cannot be transported from the intestines into the body.
Hopefully this information is helpful for you to more clearly understand common b12 absorption issues and give you some direction for low b12 symptoms.
Keep in mind, that this video is focused more on absorption issues and does not cover all the causes of b12 deficiency. You can read more about some of these in this article about b12 shots.
Why Your B12 Shots Are Not Working
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