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From Mary Shomon Your Thyroid Guide


Do You Need B-12?

by Mary J. Shomon

October, 2002 -- A study that came out of Tufts University last year found that as many as 40 percent of healthy men and women have low levels of B-12 -- and those levels were deficient even though the people were eating diets tht has amuch as three times the recommended daily intake of this critical vitamin.

Vitamin B-12, which is also known as cyanocobalamine or cobalmin, is an essential nutrient in our diet. It is required for development of red blood cells, and is used to make the protective coating surrounding nerves.

Vitamin B-12 is found mainly in animal foods such as meat, poultry, milk products, eggs, and fish.


The study was led by Katherine Tucker, PhD a nutritional epidemiologist at the Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center at Tufts University in Boston. They evaluated B-12 blood levels in 3,000 adults.

What they found was that low B-12 levels were fairly common in the entire population, but of all those texted, 39 percent had levels that were on the border or slightly below the cutoff, 17 percent had demonstrably low levels, and 9 percent had levels so low that they are considered clinically deficient.

According to Dr. Tucker, "I think there's a lot of undetected vitamin B12 deficiency out there."

B-12 deficiency can cause a type of anemia that is characterized by fewer but larger red blood cells. Other effects include walking and balance disturbances, a loss of vibration sensation, confusion, and, in seriously advanced cases, dementia. Since the body requires B12 to an inadequate supply of B12 can expose nerves to damage.

Symptoms of B-12 deficiency and B-12-related anemia include:

  • Feeling tired or weak
  • Pale appearance to the lining of lower eyelids
  • Palpitations, fast or irregular heart beat.
  • Faintness and breathlessness.
  • Hair loss
  • Bruising that occurs without reason
  • Dizziness
  • Long or unusually heavy menstrual periods
The researchers were particularly suprised by the fact that among those studied, the youngest -the 26 to 49 year olds-had similar B12 status to the group aged 65 and up. Says Dr. Tucker, "We thought that low concentrations of B12 would increase with age. But we saw a high prevalence of low B12 even among the youngest group."

The deficiencies in B-12 did not correlate with meat, poulty and fish in the diet, even those these foods are the typical source of B-12. According to Dr. Tucker, "It's not because people aren't eating enough meat," Tucker says. "The vitamin isn't getting absorbed."

Although many people can make up the deficiency by eating cereals or dairy products fortified with B-12, others had to take vitamin supplements to bring their levels up to normal.

Most people, and particularly those with autoimmune diseases, should be tested for a B-12 deficiency, and for anemia. Once diagnosed, in addition to your doctor's recommendations regarding treatment for anemia and any suggested iron supplementation, you can also consider the following recommendations:
  • Eat more foods that are good sources of iron. Concentrate on green, leafy vegetables, lean, red meat, beef liver, poultry, fish, wheat germ, oysters, dried fruit and iron-fortified cereals.
  • Help your body absorb iron better by eating foods high in vitamin C.
  • Red meat can supply iron, but also helps your body absorb iron from other foods.
  • Limit your use of tea, except herbal teas. The tannins in tea can inhibit iron absorption.
  • Avoid antacids, phosphates (found in soda, beer, ice cream, candy bars, etc.) and the food additive EDTA. These block iron absorption.
  • Increase dietary fiber to prevent constipation.
Pernicious Anemia

In other studies, it was found that as many as 10 percent to 15 percent of adults older than 65 have a vitamin B-12 deficiency called pernicious anemia.

Pernicious anemia is one of the autoimmune conditions discussed in the book "Living Well With Autoimmune Disease." The book discusses how pernicious anemia is connected with autoimmune endocrine conditions, including Hashimoto's thyroitis, thyrotoxicosis, diabetes, Addison's disease and primary ovarian failure. People with these autoimmune conditions are at higher risk of pernicious anemia, and vice versa.

Pernicious anemia is an autoimmune disease in which the body is not able to absorb enough vitamin B-12 from the digestive tract. It occurs after long-term autoimmune gastritis (inflammation of the mucosal lining of the stomach). The destruction of the gastric mucosal cells makes you unable to make intrincsic factor, a substance that enables vitamin B-12 to be absorbed from the intestine, resulting in a B-12 deficiency.

Pernicious anemia is most common in people of Celtic (i.e., English, Irish, Scottish) or Scandinavian descent. Pernicious anemia usually occurs in people aged 40 to 70 years. Among Caucasians, the mean age of onset is 60 years, but it shows up at an average of 50 with African-Americans.

While symptoms of pernicious anemia are usually slow and vague, making diagnosis difficult, the most common symptoms include weakness, sore tongue, and paresthesias (numbness, tingling, burning sensations). Other symptoms include:

  • Lack of appetite, weight loss of 10-15 pounds in about 50% of patients, due to lack of appetite
  • Low-grade fever
  • Anemia
  • Half of all patients have a smooth tongue which may may be painful and red. Burning and soreness on the tongue may also be accompanied by changes in taste and loss of appetite.
  • Constipation or several semisolid bowel movements daily
  • Numbness and tingling in hands and feet
  • Nausea, vomiting, heartburn
  • Flatulence, diarrhea
  • Sense of fullness, abdominal pain
  • Fatigue, weakness
  • Pale skin, pallor, lemon-yellow waxy appearance to the skin
  • Impaired smell
  • Bleeding gums
  • Shortness of breath
  • Headache
  • Ringing in the ears (tinnitus)
  • Loss of bladder control
  • Impotence
  • Clumsiness and unsteady gait (worse in the dark)
  • Irritability, personality changes, memory loss
  • Delusions, hallucinations
  • Premature whitening of the hair
  • Rapid heartbeat
Pernicious anemia can frequently be diagnosed through various tests, including:
  • Bloodwork to assess iron levels, typically a complete blood count (CBC), which can measure various iron levels
  • Blood tests for vitamin B-12 deficiency, and folic acid deficiencies
  • Measurement of methylmalonic acid and homocysteine, which can be elevated in pernicious anemia
  • Testing for antibodies to intrinsic factor
  • Indirect bilirubin may be elevated
  • Other red blood cells, enzymes, and serum iron saturation may be elevated
  • Sserum potassium, cholesterol, and alkaline phosphatase may be decreased
  • Other disorders that interfere with the absorption and metabolism of vitamin B-12 can produce cobalamine (Cbl) deficiency, so many of the tests to rule out and diagnose pernicious anemia focus on identifying the casue of Cbl deficiency. Some of these results include low serum Cbl levels
  • The Schilling test to measure Cbl absorption, which shows that anemia is not secondary to other causes of Cbl deficiency
Iron replacement can treat general anemia, but not pernicious anemia. For pernicious anemia, injections of vitamin B-12 (called cyanocobalamin or hydroxyocobalamin), oral folic acid therapy, or both, can reverse the production of abnormal blood cells.

To deal with acute situations, injections of the B-12 are given daily for several weeks, then twice a week for a month, and monthly thereafter.

Usually, the B-12 shots must be taken for life, although some patients can be maintained on an orally administered form of B-12.

It's difficult to get people to take monthly injections, so other forms are being investigated. In Europe, a nasal spray form of hydroxocobalamin is showing promise and is expected to reach the U.S. soon.

You can find out more about pernicious anemia and its linkages to autoimmune thyroid and other diseases in "Living Well With Autoimmune Disease"



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