Will a Vitamin B12 Deficiency Cause Weight Gain or Weight Loss?

Vitamin B12 is utilized by the body for the formation of red blood cells and DNA, brain and nerve cell development, and brain function. It is presumed that vitamin B supplements may have contributed to obesity development levels.

Vitamin supplementation has been around for over a century. Vitamins are needed for the proper functioning of every body system. Though vitamins can be found naturally in foods, some body processes make them hard to absorb, and deficiencies can occur. One such vitamin is B12. Improper amounts can lead to vitamin B12 deficiency, and several health mishaps can occur. The mishaps can lead to alterations in bodily processes, like weight gain and loss. But can we directly link vitamin B12 deficiency and weight gain and loss? The studies are still being conducted. 

Vitamin B12 is known as cobalamin. It is utilized by the body for the formation of red blood cells and DNA. It is also used for brain and nerve cell development, and brain function. It is found in some animal meats naturally. It combines with the proteins in our dietary meals.  Via chemical digestion in the stomach, vitamin B12 is released in free form to combine with intrinsic factors to be reabsorbed by the intestines. 

Vitamin B12 is a complex vitamin that is water soluble. Though it is naturally found in foods like fish, meat, and dairy, it is sometimes added to foods, and used in capsule form as a dietary supplement. Foods fortified with B12 and B12 supplements contain the free form of B12 so they are more readily absorbed. B12 shots are often prescribed by medical providers to treat B12 deficiencies and pernicious anemia.

Vitamin B12 vitamins are part of the complex vitamin supplementation group that is known to increase energy levels and elevate your mood. Those with a deficiency may notice an increase in their level of energy after supplementation. This is because vitamin B12 is directly responsible for making healthy red blood cells and eliminating anemia symptoms. Medical studies do not yet have proper evidence to promote the use of vitamin B12 supplementation without a B12 deficiency. 

Vitamin B12 deficiency anemia occurs when your body does not produce enough adequate red blood cells because of a lack of B12. Red blood cells are needed to transfer oxygen to the periphery of your body. If you do not have enough red blood cells, your body will not function properly due to a lack of oxygen in your organs and tissue. Vitamin B12 often occurs in a combination with deficiency of vitamin B6, or folate deficiency anemia.

You may be at risk of having vitamin B deficiencies if you have Crohn's disease, autoimmune diseases, HIV, are elderly, or have a family history of the disease. Vitamin B12 deficiency anemia is most common in people with ancestral history in Northern Europe. It is caused by either lack of intrinsic factors or surgical removal of parts of the digestive system that bypass the small intestine. Intrinsic factor is a protein needed so that B12 can be absorbed. This anemia is also known as pernicious anemia. The end of the small intestine is where the absorption of vitamin B12 takes place. Taking B12 supplements is more effective than eating vitamin-rich foods. B12 injections are the most effective. 

There are several foods rich in both B12 and B6 that can be easily incorporated into your diet. But those with diets low in animal protein, like vegetarians or vegans, are at high risk for deficiencies. Foods rich in B vitamins include:

• Meat
• Milk
• Eggs
• Poultry
• Fortified cereals
• Shellfish
• Vegetables like spinach, sprouts, soybeans, romaine lettuce, beans, broccoli, peas, asparagus

In your body, cell energy production and DNA synthesis both rely on Vitamin B12. Because of these properties, B vitamins have been documented to promote fat gain. At levels below toxicity, B vitamins have traditionally been known to promote gains in body fat. Certain studies have shown concoctions containing high levels of vitamin B promote weight gain in infants, specifically gains in fat mass. This is a widely accepted risk for obesity development in children. 

Since synthetic vitamins were first used in the late 1930s, humankind has undergone the most massive increase in vitamin use in history. It is presumed that vitamin B supplements may have contributed to obesity development levels. Some ecological studies have demonstrated a connection between vitamin B use and obesity and diabetes prevalence. The consumption of foods fortified with B vitamins has shown an increase in the prevalence of obesity over the years. 

In addition to physiological changes that occur with aging, and also social risk factors, the elderly population is at a risk for protein malnutrition and vitamin deficiency. Having gastric surgery also increases the risk of b12 deficiency. Studies show that supplementation with parenteral vitamin B12 and nutritional assessments have shown weight maintenance or gain with early intervention. This study is a reminder of the prevalence of deficiencies and maturity in the elderly population in various communities. 

In regards to loss of weight, there is no documented outcome that supports vitamin B12 shots or injections promoting weight loss.

Since vitamin B12 is water soluble, portions not metabolized by the body will be eliminated via urination. Supplementation of vitamin 12 in amounts up to 1000 mcg can be consumed safely. Though there have been no side effects documented from vitamin B12 use from either supplementation or food consumption, you should always check with your doctor prior to beginning supplementation of any type. Supplementation of some vitamins at higher doses level can cause toxicity. Toxic effects can be severe and can possibly lead to death. An example of this is sudden infant death syndrome traced back to high body serum levels of thiamin.