Vitamin D is essential for a range of bodily functions. Dietary sources provide some vitamin D, but most comes from exposure to sunlight. vitamin B12 deficiency means that your body does not have enough of this vitamin. You need B12 to make red blood cells, which carry oxygen through your body. Not having enough B12 can lead to anemia, which means your body does not have enough red blood cells to do the job. This can make you feel weak and tired. Vitamin B12 deficiency can cause damage to your nerves and can affect memory and thinking.
People have an annual blood test to check for a vitamin D deficiency. The result will show serum vitamin D levels in nanomoles/liter (nmol/l). Healthy levels of serum vitamin D are between 50 nmol/l and 125 nmol/l. Enough B12 from eating meat, eggs, milk, and cheese. Normally, the vitamin is absorbed by your digestive system—your stomach and intestines. Vitamin B12 deficiency anemia usually happens when the digestive system is not able to absorb the vitamin.
Low levels of B12 cause your folate levels to drop. However, if you have a B12 deficiency, correcting low folate levels may simply mask the deficiency and fail to fix the underlying problem. People with a B12 deficiency often look pale or have a slight yellow tinge to the skin and whites of the eyes, a condition known as jaundice. This happens when a lack of B12 causes problems with your body’s red blood cell production. Anemia can also happen if you don’t eat enough foods with B12, but this is rare. People who eat a vegan diet and older adults who don’t eat a variety of foods may need to take a daily vitamin pill to get enough B12. Other causes include drinking alcohol and taking some prescription and nonprescription medicines.
Causes of V-D deficiency-
Vitamin D deficiency can happen when:
does not consume enough vitamin D
is unable to absorb or metabolize the vitamin D
does not spend enough time in ultraviolet B (UVB) sunlight
Diet: People who do not eat enough vitamin D-rich foods, including fortified dairy products and cereals, may have low levels of vitamin D.
Lifestyle factors: Some people spend little time outdoors due to work, ill health, a lack of outdoor space in their neighborhood, or other factors. These people have less opportunity to expose their skin to sunlight. Those who wear clothes that cover all of their body, whether to protect it from the sun or for cultural or religious reasons, may also have a higher risk of a deficiency.
Absorption problems: Crohn’s disease, celiac disease, and other conditions can affect how the intestines absorb nutrients, including vitamin D.
Medications: Some drugsTrusted Source reduce the body’s ability to absorb or synthesize vitamin D. These include steroids and some drugs for lowering cholesterol, among others.
Smoking: Levels of deficiency appear to be higher among smokersTrusted Source. Some experts have suggested that smoking may affect the gene that activates the production of vitamin D-3 in the body.
Atrophic gastritis, in which your stomach lining has thinned
Pernicious anemia, which makes it hard for your body to absorb vitamin B12. Conditions that affect your small intestine, such as Crohn’s disease, celiac disease, bacterial growth, or a parasite. Alcohol misuse or heavy drinking can make it harder for your body to absorb nutrients or prevent you from eating enough calories. One sign that you lack enough B12 may be glossitis, or a swollen, inflamed tongue. Immune system disorders, such as Graves’ disease or lupus.
Genetic factors may also affect how vitamins are metabolized and the consequences of supplementation in various clinical situations. Not enough is yet known about how to use genetic information to guide clinical decisions about vitamin deficiencies and supplementation dosing, but that information is likely to become available in the future.