Vitamin B12 - Symptoms and Toxic Effect Vitamin B12

Vitamin B12, also called cobalamin, occurs naturally in animal foods. It can also be added to foods or dietary supplements. Vitamin B12 is needed for the formation of red blood cells and DNA. It also plays a key role in brain and nerve cell function and development.

Vitamin B12 binds to the proteins in the foods we eat. In the stomach, hydrochloric acid and enzymes break the bond of vitamin B12 into its free form. From there, vitamin B12 binds to a protein called intrinsic factor so it can be absorbed further down in the small intestine.

Supplements and fortified foods contain B12 in its free form, making it easier to absorb. There is a variety of vitamin B12 supplements available. Although it is claimed that certain forms - such as sublingual tablets, or liquids that are placed under the tongue to be absorbed through the tissues in the mouth - are better absorbed than traditional tablets, studies have not shown a significant difference. Vitamin B12 tablets are available in high dosages, well above the recommended daily allowance, but these high amounts are not necessarily the amount that will be absorbed, as a sufficient intrinsic factor is also required. In cases of severe vitamin B12 deficiency due to insufficient intrinsic factors (pernicious anemia), physicians may prescribe B12 injections into the muscle.

Source of Food

1. Fish
2. Liver
3. Red Meat
4. Eggs
5. Poultry
6. Dairy products such as milk, Cheese, and Yogurt
7. Fortified Nutritional Yeast
8. Fortified Breakfast Cereals
9. Enriched soy or Rice Milk

Symptoms of Weakness and Toxic Effect

Measuring vitamin B12 in the blood is actually not the best way to determine if someone has a deficiency, since some people with a deficiency may have normal blood levels of B12. Blood levels of methylmalonic acid, a protein breakdown product, and homocysteine are better markers that capture actual vitamin B12 activity. These levels increase in the presence of vitamin B12 deficiency. It is estimated that up to 15% of the general population is deficient in vitamin B12.

Factors that may cause vitamin B12 deficiency:

1- Avoiding animal products: People who do not eat meat, fish, poultry, or dairy products run the risk of vitamin B12 deficiency, as it is naturally found only in animal products. Studies have shown that vegetarians have low blood levels of vitamin B. [5] For this reason, people who eat a vegetarian or vegan diet should include B12-fortified foods or a B12 supplement in their diet. This is especially important for pregnant women, as the fetus needs sufficient vitamin B12 for neurological development and a deficiency can lead to permanent neurological damage.

2- Absence of intrinsic factor: Pernicious anemia is an autoimmune disease that attacks and possibly destroys intestinal cells, resulting in the absence of intrinsic factor, which is critical for the absorption of vitamin B12. When vitamin B12 deficiency occurs, other types of anemia and neurological damage can result. Even taking a high-dose B12 supplement cannot solve the problem because the intrinsic factor is not available for absorption.

3- Insufficient stomach acid or medications that cause decreased stomach acid: A much more common cause of B12 deficiency, especially in the elderly, is a lack of stomach acid because stomach acid is needed to release vitamin B12 from food. An estimated 10-30% of adults over age 50 have difficulty absorbing vitamin B12 from food. People who regularly take medications that suppress stomach acid in conditions such as gastroesophageal reflux disease (GERD) or peptic ulcer diseases - such as proton pump inhibitors, H2 blockers, or other antacids - may have difficulty absorbing vitamin B12 from food. These medications may slow the release of stomach acid or decrease its production. In theory, this may prevent the vitamin from being converted to its free, usable form in the stomach; however, studies have not shown that deficiency is more common in people taking these medications. People who take these medications for a long period of time and who are at risk for vitamin B12 deficiency for other reasons should be closely monitored by their doctor. You can also use fortified foods or supplements containing vitamin B12, as these forms are usually well absorbed and do not require stomach acid.

4- Surgery on the intestines or digestive disorders that cause malabsorption: Surgeries that affect the stomach, where intrinsic factor is made, or the ileum (the last part of the small intestine), where vitamin B12 is absorbed, can increase the risk of deficiency. Certain diseases such as Crohn's disease and celiac disease that negatively affect the digestive tract also increase the risk of deficiency.

Symptoms:

1. Megaloblastic anemia—a condition of larger than normal sized red blood cells and a smaller than normal amount; this occurs because there are not enough vitamin B12 in the diet or poor absorption
2. Pernicious anemia—a type of megaloblastic anemia caused by a lack of intrinsic factors so that vitamin B12 is not absorbed
3. Fatigue, weakness
4. Nerve damage with numbness, tingling in the hands and legs
5. Memory loss, confusion
6. Dementia
7. Depression
8. Seizures

Toxic Effect:

Vitamin B12 is a water-soluble vitamin, so unused amounts leave the body through the urine. Generally, up to 1000 mcg per day in tablet form is considered safe to treat a deficiency. The Institute of Medicine notes that no adverse effects of excessive dietary or supplemental vitamin B12 intake have been found in healthy people. However, it is important not to start high-dose supplementation without first talking to your doctor.

Important Information:

1- Taking a B vitamin complex is often touted as a way to boost energy and mood. People with a B vitamin deficiency may feel an increase in energy levels after taking the supplement, as the vitamin is directly involved in the formation of healthy blood cells and can correct any anemia that may be present. However, there is no evidence of benefit when people without deficiency take supplemental B vitamins.

2- People on a vegan diet are often advised to take brewer's yeast or nutritional yeast for its B12 content. However, yeast does not naturally contain this vitamin, but only when it is fortified with it. Note that certain brands, but not all, contain B12.

3- Nori (purple kelp), the dried edible seaweed used to make sushi rolls, is sometimes touted as a plant-based source of vitamin B12. It does contain small amounts of active vitamin B12, but the amount varies depending on the type of seaweed, and some contain none at all. Therefore, it is not considered a reliable food source.