Vitamin D and B12 aren't linked in the sense that one causes the other but is relatively common for someone to fall short on both of these vitamins.  For example, people who don't eat any animal products (vegans) typically need supplemental vitamin D and B12 either from fortified foods or supplements.  Both of these vitamins are found primarily found in animal foods, although plant-based products can be fortified with D such as soy milk.  Sunlight is another source of vitamin D. 

Another example would be someone who had gastric bypass surgery -- they are at higher risk for vitamin D and B12 deficiencies.  People with excess weight tend to have lower levels of vitamin D and additional B12 is needed after this type of surgery because absorption occurs in the stomach. 

A third example is someone who is elderly.  They absorb less vitamin B12 from food and do not make as much vitamin D from the sun.  Work with your healthcare provider or a registered dietitian to make sure you are getting enough of both of these vitamins.

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There isn't a direct link between a deficiency in these two vitamins, but it likely represents a common denominator.

Some vitamins require fat to be absorbed in the intestine. These four vitamins A,D,E, and K require fat and a very low intake can produce a deficiency in them. Damage to the pancreas or intestine can also interfere with the absorption of these vitamins.

Vitamin B12 requires a few additional modifications in the body to be absorbed. It does not require fat but a factor that is produced in the pancreas , however its absorption also requires a healthy pancreas and intestinal lining.

This answer should not be considered medical advice...This answer should not be considered medical advice and should not take the place of a doctor’s visit. Please see the bottom of the page for more information or visit our Terms and Conditions.