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What Causes Deficiencies in Iron and Vitamins B-12, B-6 and D?

author image Elle Paula
Elle Paula has a Bachelor of Science in nutrition from Framingham State College and a certificate in holistic nutrition from the American College of Healthcare Sciences. She is also a licensed aesthetician with advanced training in skincare and makeup. She plans to continue on with her education, complete a master's degree program in nutrition and, ultimately, become a registered dietitian.
What Causes Deficiencies in Iron and Vitamins B-12, B-6 and D?
Being a vegan can cause iron deficiency. Photo Credit: Tuned_In/iStock/Getty Images

A nutrient deficiency occurs when your body does not contain adequate amounts of a specific vitamin or mineral to perform its physiological functions. Over time, a lack of a specific nutrient can lead to disruptions in body processes and the development of physical symptoms. While most people quickly associate nutrient deficiencies with a lack of the specific nutrient in the diet, there is sometimes another underlying cause.

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Iron Deficiency

Two-thirds of the iron in your body is located in the hemoglobin in your red blood cells, according to “Nutrition and You” by Joan Salge Blake. Because such a high amount of iron is in your red blood cells, blood loss is a common cause of iron deficiency. Blood loss may occur as a result of trauma, abnormal menstrual periods or internal bleeding from ulcers or colon cancer. Iron deficiency can also develop as a result of a decreased ability to absorb iron due to intestinal disorders or prior intestinal surgery. A lack of iron in the diet can also cause iron deficiency. This is most common in strict vegetarians or vegans because the most absorbable forms of iron are found in animal foods.

Vitamin B-12 Deficiency

The most common cause of a vitamin B-12 deficiency is a lack of intrinsic factor, a protein produced by cells in your stomach. Without intrinsic factor, you cannot physically absorb this water-soluble vitamin. A lack of intrinsic factor can be caused by autoimmune disorders or prior stomach surgery. Vitamin B-12 deficiency may also develop due to abnormalities in the small intestine that cause a decreased absorption rate of the vitamin. Possible causes include tapeworm infection, bacterial overgrowth and certain types of medication. Digestive diseases can also cause vitamin B-12 deficiency. Lack of vitamin B-12 in the diet can eventually lead to a deficiency of this B-complex vitamin, but because your body can store years’ worth of the vitamin, such a deficiency can take a long time to develop.

Vitamin B-6 Deficiency

Vitamin B-6 deficiency is rare in the United States, according to the Office of Dietary Supplements. One of the most common causes of a vitamin B-6 deficit is alcohol abuse. Alcohol increases the rate at which your body destroys and removes vitamin B-6. Alcoholics also generally have a poor diet. Asthmatic children taking medicine containing theophylline are also at risk of vitamin B-6 deficiency because the medication decreases your body’s vitamin B-6 levels.

Vitamin D Deficiency

Like all other vitamins, you can obtain the vitamin D from foods and supplements. Vitamin D is unique in that your skin is able to synthesize it with the aid of ultraviolet-B rays from sunlight. Because vitamin D is fat-soluble, your body needs dietary fat to absorb it properly. Disorders that reduce the amount of fat you are able to absorb can cause decreased absorption of vitamin D as well. These disorders, which include celiac disease, Crohn’s disease and bile duct disorders, can lead to a vitamin D deficiency. Such a deficiency may also develop if you do not have adequate exposure to sunlight. As you age, your ability to synthesize vitamin D in the skin naturally declines, increasing your risk of vitamin D deficiency. A diet low in vitamin D may cause deficiency, but this is rare in developed countries.

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