Can Dehydration Cause High B12 Levels? (What High Vitamin B12 Levels Mean)

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Your Vitamin B12 levels may spike up when you’re taking B12 supplements or eating chicken, meat, fish, eggs, milk, or other dairy products, and B12 fortified cereal. Dehydration won’t result in elevated B12 levels in your blood. But, it can cause mild to severe health problems like mild heat cramps, urinary tract infection (UTI), seizures, loss of consciousness, or in worst cases, multiple organ failure and even death. High B12 levels in your body may signal blood disorders, organ failures, tumors, and inflammatory diseases.

Vitamin B12, also known as cobalamin, is just as essential as the other vitamins and minerals we need. 

Adult men and women should take at least 2.4 mcg of Vitamin B12 every day. You can get it from eating poultry, meat, fish, dairy products, and breakfast cereals.

If you’ve been following a plant-based diet, your doctor may prescribe you take vitamin B12 supplements. These supplements are also recommended for older people who need to increase their vitamin B12 intake.

Below we’ll talk more deeply about vitamin B12. Why is it essential? And, should you be concerned if you have high levels of vitamin B12 in your body?

What is the role of vitamin B12?

Vitamin B12 boosts your cognitive function, helps in your nerve and cell function, aids in producing your DNA, and forms the hemoglobin of your red blood cells. 

A chart showing all the vitamins along with foods that these vitamins can be found in.

There’s actually a condition called vitamin B12 deficiency, which is more common than cases of elevated B12 levels.

However, clinical studies have proven that you can’t overdose on vitamin B12.

Unlike fat-soluble vitamins like A & D, vitamin B12 is water-soluble. 

This means that the excess amount of the vitamin your cells won’t take up will eventually be eliminated in your urine. 

Patients experiencing high vitamin B12 levels are very rare compared to vitamin B12 deficient people. 

However, it’s important to know what causes the elevated vitamin B12 levels in your blood because it may indicate serious health complications.

What does dehydration do to your body?

When your body loses more water than you intake, it will cause dehydration. It will result in imbalances in your bodily minerals, which will affect the processes and functions of your body. 

A common warning sign of dehydration is getting really thirsty. Other symptoms of dehydration include:

  • Having darker colored, strong-smelling urine
  • Headaches or migraine attacks
  • Mood swings
  • Slower digestion and lesser urination
  • Drop in blood pressure and oxygen levels

Anybody can become dehydrated, but babies, older people, diabetic and/or alcoholic people, and athletes are more prone to dehydration. 

The most common cause of dehydration is not drinking enough fluid every day. 

Other factors like the following may also cause too much water loss in your body:

  • The climate
  • The amount and intensity of your daily physical activities
  • Your diet and habits
  • Your age and health condition
  • Diarrhea and vomiting

The average daily amount of water that men should take is around 15.5 cups (3.7 L), while women should have at least 11.5 (2.7 L). These include the fluids from the food and other beverages you have every day. 

There’s no literature supporting dehydration elevating vitamin B12 levels in your blood. However, dehydration can lead to serious health complications, including:

  • Mild heat cramps to heat exhaustion that can result in heatstroke
  • Urinary tract infection (UTI) and other kidney problems like kidney stones and kidney failure
  • Seizures
  • Loss of consciousness
  • Low blood volume shock-may lead to multiple organ failure 
  • Coma and death from severe dehydration

What causes elevated B12 levels in your body?

A young woman is drinking a smoothie that's loaded with vitamin B12

It’s normal for your vitamin B12 levels to shoot up, especially when taking vitamin B12 supplements or B12-rich food. These will eventually go down after some time.

But, you must consider other possible sources of the vitamin, such as a multivitamin, a pre-workout drink, a protein powder, etc. These things could contribute to the increase of your B12 levels. 

Vitamin B12 supplements are commonly prescribed in treating patients with pernicious anemia, chronic fatigue, and other medical problems.

If your tests show persistent elevated vitamin B12 even without you taking supplements, it could signify a chronic illness.

Patients often worry about taking high doses of vitamin B12 supplements cause of the unrealistic fear of toxicity and overdosing. 

But, no clinical studies show evidence of B12 intoxication and overdose. 

High levels of vitamin B 12 in your blood could be a side effect or sign of various underlying health conditions such as the following:

1. Solid organ cancers

High vitamin B12 could nonspecifically indicate tumors in your organs, commonly on the liver. 

When the liver cells are damaged, the organ can’t take up an adequate amount of vitamin B12 it needs from your bloodstream. 

The previously stored vitamin B12 in your liver may also be released. And if your organ wouldn’t be able to take up and keep more vitamin B12, a high amount of the said vitamin will stay in your blood.

Tumors may occur in your breast, colon, stomach, pancreas, kidney, and prostate. 

2. Liver disease

Hepatitis, when left untreated or inadequately treated, can result in cirrhosis, liver failure, or liver cancer. 

Your liver is the largest solid organ in your body, storing the largest amount of vitamin B12.

When it malfunctions, it can’t continue to take up and keep much of the vitamin B12 from your bloodstream, resulting in the increased release of the vitamin, rising its levels in your blood.

3. Leukemia and blood-related diseases

Cancer of the bone marrow, particularly chronic myelocytic leukemia (CML), describes an increased production of the white blood cells in your blood. 

When you suffer from CML, your cells won’t be able to absorb vitamin B12. As a result, the high amounts of the vitamin will only circulate in your bloodstream and will never be used by your cells.

Another type of blood cancer is polycythemia vera which characterizes the over-production of red blood cells in your bone marrow.

In a rare but worst-case scenario, polycythemia vera can transform into a long-term blood cancer called myelofibrosis

All these blood diseases and other types like hypereosinophilic syndrome will restrict your bodily cells from absorbing and using the vitamin B12 in your body. 

4. Kidney Disease

Your kidneys filter your blood from the toxins and wastes in your body.

When you develop diabetic kidney disease or kidney failure, you won’t be able to eliminate the excess vitamin B12 or other wastes present in your blood.

Thus, your vitamin B12 levels would stay high.

5. Inflammatory or autoimmune diseases 

Inflammatory and/or autoimmune diseases like lupus may also cause the vitamin B12 levels in your blood to be persistently elevated.

When your own immune system attacks and destroys healthy cells and tissues of your organs, then your overall organ systems would no longer function normally.

In general, your body can’t absorb and use the vitamin anymore.

Signs and symptoms of high vitamin B12 levels

The vitamin B12 that your body won’t use will be excreted in your urine. You’ll most likely need to replenish this nutrient every day through your diet or supplementation.

There are no reported severe side effects or symptoms from intaking high doses of the vitamin.

Sometimes, you may experience symptoms but only temporarily, such as:

Other potential side effects of B12 injectable supplements may include muscle cramps, weakness, and irregular heartbeat. 

Remember to consult your doctor when other unusual and severe symptoms occur because, as mentioned before, high levels of vitamin b12 may signal underlying severe health conditions. 

What to do with elevated vitamin B12 levels?

Sometimes, high vitamin B12 levels may indicate that you’re deficient in the vitamin. 

Now, that sounds very ironic, right? Well, there are things you need to consider here. 

Suppose your tests show high vitamin B12 levels and high methylmalonic acid and homocysteine in your blood or urine; at the same time, you’re experiencing some symptoms; you must be vitamin B12 deficient.

Your doctor may prescribe you take vitamin B12 supplements until your methylmalonic acid levels go down. 

If you have persistent elevated B12 levels with/without taking any supplements, please schedule a check-up with your doctor and ask to run a test on your blood, liver, and kidney. 

Another test you can do is the holotranscobalamin test which will eventually rule out if it’s a problem with your white blood cells or genetically caused. However, this test is not widely available and is mainly done only in Europe and UK. 

If all of your tests are normal, your doctor may monitor your vitamin B12 levels as they should lower within a reasonable amount of time. 


Dehydration may not directly cause your B12 levels to spike up. It’s when you’re severely dehydrated that results in organ failures (i.e., kidney failure), which these conditions cause elevated levels of the vitamin in your body.

Sometimes, you might actually be vitamin B12 deficient even when you have high B12 levels if your blood/urine tests also show high levels of methylmalonic acid and homocysteine. Then, you might need to take B12 supplements. 

No patients have experienced severe side effects nor showed signs of intoxication on high doses of vitamin B12.

It’s water-soluble, so you’ll most likely urinate excess amounts of the vitamin. That is if your kidneys are perfectly functioning well. 

Please let your doctor monitor your B12 levels if tests show that it’s persistently high even when you’re not taking any supplements.

You must let your doctor check the status of your blood, kidney, liver, and other organs, too. 

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Reana Jean Cuevas
Mabuhay! I'm Reana Jean Cuevas. A healthy body means living well with no worries-just happiness and more life adventures. Taking care of my body and well-being is an investment for my career and future. I was a volunteer at the Philippine Red Cross. I joined the training to become a first-aider and be able to provide other health and safety services in my community. I love discussing anything but mainly first-aid, home remedies, and women's health.

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Nutrition & Diet