Vitamin B Deficiency, Fatigue, Ridged Nails & Rash

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Vitamins are essential nutrients for your body. Without an adequate amount of B vitamins you can develop deficiency that can lead to fatigue, ridged nails and rash, among several other symptoms. There are eight B vitamins you need to get every day to avoid deficiency. Consult your doctor about B vitamins and whether you are at risk of developing deficiency.

B Vitamins

The B vitamins are called thiamine, riboflavin, niacin, pantothenic acid, vitamin B6, biotin, folic acid and vitamin B12. They all have an important role for your health; you need all of them for your body to function normally. B vitamins are water-soluble and are not stored in your body. Thus, you need to get them from food or supplements every day to avoid deficiency.


It is essential that you get the recommended dietary allowance -- or RDA -- of all B vitamins. Current guidelines suggest adults get around 1.2 milligrams of thiamine, 1.3 milligrams of riboflavin, 16 milligrams of niacin, 5 milligrams of panthoenic acid, 1.3 milligrams of vitamin B6, 30 micrograms of biotin, 400 micrograms of folic acid and 2.4 micrograms of vitamin B12. If you are lacking even one of these B vitamins, you can develop deficiency. The symptoms of deficiency can be very similar for the different B vitamins, such as fatigue, or very specific, such as a scaly rash.


Fatigue can be caused by inadequate dietary intake of many B vitamins. Vitamin B12, folic acid, vitamin B6 and riboflavin deficiency can cause anemia. Anemia is a condition that affects the oxygen-carrying capacity of your blood. Without an adequate amount of oxygen, you can suffer from fatigue and weakness. Lack of niacin in your diet can cause pellagra, a condition that may involve neurological symptoms such as fatigue. Lack of thiamine can cause beriberi, another condition that can be associated with fatigue. Your doctor will need to do a blood test to evaluate which B vitamin or vitamins you are missing in your diet. Once your doctor knows what is causing the fatigue, he can advise what foods you should increase in your diet or what B-vitamin supplements to take.

Skin Rash

Rash can be a symptom of vitamin B6, biotin, niacin and riboflavin deficiency. Unlike fatigue, skin rashes caused by B-vitamin deficiencies are more distinct from one another. For example, inadequate intake of biotin can cause a red rash around your eyes, nose, mouth and genitalia. This is very different form the rash caused by inadequate intake of niacin, which causes thick, scaly rash on skin areas exposed to sunlight, or from inadequate intake of riboflavin that leads to seborrheic dermatitis, which is characterized by moist and scaly skin inflammation.

Ridged Nails and Anemia

Besides causing fatigue, another symptom of anemia can be ridged and brittle finger nails. Vitamin B12 and/or folic acid deficiency can cause megaloblastic anemia, characterized by abnormally large and shaped red blood cells. Getting inadequate amounts of vitamin B6 from your diet can cause sideroblastic anemia, while inadequate dietary intake of riboflavin can alter iron metabolism and cause iron-deficiency anemia. Although the exact mechanisms behind these different forms of anemia vary, they can all cause your fingernails to become ridged and brittle. Your doctor will need to do a blood test to evaluate the reason for the anemia.