Vitamin B12, one of the eight B vitamins, is vital to the healthy function of every cell in the body. Insufficient vitamin B12 intake — or insufficient absorption in the gastrointestinal system — can cause a wide range of health problems. In addition, some of these can be confused with complications related to diabetes, so it’s important to know the possible causes, signs, and symptoms of deficiency. How much do you know about vitamin B12? Take this quiz and find out!
1. The primary functions of vitamin B12 in the body are the formation of red blood cells and the maintenance of a healthy nervous system.
2. Vitamin B12 is naturally available in which of the following foods? (More than one answer may be correct.)
3. Insufficient amounts of B12 in the body can cause which of the following symptoms? (More than one answer may be correct.)
A. Tingling or numbness in the hands or feet.
B. Diarrhea or constipation.
D. Weakness and fatigue.
E. Confusion, memory loss, or dementia.
4. B12 deficiency is a common side effect of long-term treatment with which of the following diabetes drugs?
A. Thiazolidinediones (brand names Actos, Avandia).
B. Metformin (Glucophage, Glucophage XR, Riomet, Fortamet, Glumetza).
C. Sulfonyureas (DiaBeta, Glynase, Micronase, Glucotrol, Glucotrol XL, Amaryl).
D. DPP-4 inhibitors (Januvia, Onglyza).
5.Vitamin B12 supplements can be taken in which of the following ways? (More than one answer may be correct.)
A. By injection.
B. By pill, either swallowed or sublingually (absorbed under the tongue).
C. By nasal spray.
D. In B12-fortified foods, such as certain breakfast cereals.
6. Bodily damage from B12 deficiency can be permanent.
1. TRUE. Vitamin B12, along with related B vitamins B6 and B9 (better known as folic acid), is important in the formation of hemoglobin, the oxygen-carrying component of red blood cells. It also plays a key role in making the fats and proteins that form myelin, the material that covers and insulates the nerves in the brain and spinal cord. Additionally, vitamin B12 has a part in almost a hundred different reactions that govern metabolism and tissue synthesis, growth, and repair. Along with vitamin B6 and folic acid, it also aids in the formation of hormones and neurotransmitters, chemicals that nerve cells use to send signals to each other.
2. A and B. Vitamin B12 is naturally present in all foods of animal origin, including fish, meat, eggs, and dairy products. Vitamin B12 is generally absent in plant-based foods, but many processed foods such as cereal, nutrition bars, and some beverages and snacks are fortified with vitamin B12. The Dietary Reference Intake for men and nonpregnant or lactating women 14 years of age and older is 2.4 micrograms (mcg) per day. Three ounces of baked trout has 14.7 mcg of vitamin B12, a large hard-boiled egg has 0.6 mcg, and an ounce of low-fat Cheddar cheese has 0.2 mcg.
Lettuce and potatoes are not sources of vitamin B12. However, dark leafy lettuces (such as endive, Boston, or Bibb) and potatoes are sources of folic acid, one of the B vitamins that works with vitamin B12 in many of its functions.
3. A, B, D, and E. There are many symptoms of vitamin B12 deficiency. These include fatigue, weakness, poor balance and coordination, loss of appetite, weight loss, soreness of the mouth and tongue, diarrhea or constipation, and numbness, burning, and tingling in the hands and feet, which can be mistaken for diabetic neuropathy. Some of these symptoms occur as a result of anemia caused by vitamin B12 deficiency, but the neurological changes (numbness, tingling, etc.) can occur even in the absence of anemia. Early identification of B12 deficiency and intervention is therefore important. Vitamin B12 deficiency does not cause nausea.