Your body absorbs only as much as it needs, and any excess passes through your urine. High doses of vitamin B-12, such as those used to treat a deficiency, might cause: Headache. Nausea and vomiting.
Can you overdose on vitamin B12? Overdosing on vitamin B12 is unlikely. Because vitamin B12 (cobalamin) is a water-soluble vitamin and your body excretes it daily in your urine, it doesn't build up in the body like fat-soluble vitamins—like vitamin D—do.
Healthcare professionals have not identified an upper limit blood level of vitamin B-12. The body will typically excrete excess vitamin B-12 that a person gets from the diet or via supplements. The body does not absorb vitamin B-12 supplements very effectively.
There is no risk of an overdose when taking large amounts of vitamin B-12 such as 1000 mcg, because it is a water-soluble vitamin. Meaning the body will use the amount that it needs then the excess will be excreted through urine.
High vitamin B12 is a symptom of an underlying illness that causes the amount in your blood to increase. For example, a damaged liver may release the vitamin out of storage and into the blood. In early stages, illnesses associated with high vitamin B12 often have generic symptoms, such as fatigue and loss of appetite.
The usual dose for: diet-related deficiency is 50 micrograms to 150 micrograms, taken once a day. B12 deficiency not caused by your diet is one to two 1,000 microgram tablets, taken once or twice a day – this is usually if you cannot have vitamin B12 injections.
Vitamin B12 deficiency can have distressing neuropsychiatric symptoms. It can have an etiological role in clinical presentations like depression, anxiety, psychosis, dementia, and delirium, requiring screening of at-risk populations.
One Possibility: Supplement Allergies
Thus if you're otherwise healthy but still continue to feel tired after taking a B-12 supplement, it could be a sign of a mild allergic reaction. If a rash, difficulty breathing or swelling coincides with taking your dose of B-12, get to the doctor right away.
The recommended daily amount for B12 is 2.4 mcg for adults. Pregnant and lactating women need higher amounts [1]. There is no upper intake limit for vitamin B12 because there is no known toxicity [2]. Most vitamin B12 supplements provide a range of strengths between 500 to 5,000 mcg [2].
As summarized in the table provided, vitamin B12 (cobalamin) absorption and utilization by the body can be compromised with the chronic use of certain medications which include: colchicine, chloramphenicol, ethanol, histamine 2 receptor antagonists (H2RA), metformin, and proton pump inhibitors (PPI).
Vitamin B12, for example, should definitely be taken in the morning. This is because it is important for energy metabolism, which may interrupt your sleep if taken at night.
Fat-soluble and water-soluble vitamins
For example, although it's safe to take vitamin D with vitamin B12, it's not advisable, says Virgilio Sanchez, MD, a board certified family medicine physician at Conviva Care Center in Miami, Florida.
Vitamin B12 is considered an important brain and nervous system micronutrient and is often used for anxiety. It helps to ensure normal function for your nerves, which can help combat physical symptoms of anxiety.
Once you begin treating your vitamin B12 deficiency, it can take up to six to 12 months to fully recover. It is also common to not experience any improvement during the first few months of treatment. If you can, it's a good idea to address what's causing the deficiency.
Nervous System Reactions
After getting a vitamin B12 injection some people may experience a disturbance to the nervous system. These symptoms may include dizziness, difficulty walking normally, nervousness, anxiety, weakness and uncoordinated movements.
Deficiency of Vitamin B12 can result in hematological changes, neurological and psychiatric problems, which can manifest as irritability, changes in personality, depression, and memory loss [9]. It is also known to worsen depression by excitotoxic reactions caused by the accumulation of homocysteine [10].
Some of the negative side effects of vitamin B overdose include mood swings, restlessness, depression, and panic attacks. Mood swings can worsen in people who suffer from paranoia, confusion, or mental fogginess; due to the high doses of vitamin B complex.
Comparing the sublingual method to vitamin B12 injections, research found that taking B12 under the tongue had a higher absorption rate, making it a better option (Bensky, 2019). Taking vitamin B12 sublingually may also be a good option for people with a condition called pernicious anemia.
Bananas are a cheap, healthy, and nutrient-dense fruit that can easily become a part of every individual's diet. It is one of the best fruits rich in vitamin B12. Bananas also contain fibre and potassium. It helps manage blood pressure, reduce stress, and relieve constipation and ulcer problems.
There are certain foods that also need a cut-down in case of vitamin B12 deficiency. “Some foods and drinks can interfere with vitamin B complex intake like alcohol, caffeine and processed foods, etc should be avoided completely,” Shah added.
Neurological changes
memory loss. pins and needles. loss of physical co-ordination (ataxia), which can affect your whole body and cause difficulty speaking or walking. damage to parts of the nervous system (peripheral neuropathy), particularly in the legs.