Safety and side effects 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.
Even the lowest doses in B12 supplements are many times the recommended dietary allowance. Doses up to 1,000 mcg, though unnecessary, aren't harmful.
For B12 deficiency, a typical injection dose is 1,000 mcg once a week for 4 to 8 weeks and then 1,000 mcg once a month. But dosages can vary depending on if you're treating severe, mild, or asymptomatic B12 deficiency.
In the absence of a consensus on the threshold that defines an abnormal increased B12 level, elevated B12 is generally defined as a level higher than the upper limit of the reference range, i.e., around 1000 +/− 100 ng/L (738 +/− 73.8 pmol/L) [2,3,4].
It may take a few weeks before your vitamin B12 levels and symptoms (such as extreme tiredness or lack of energy) start to improve. If you have hydroxocobalamin injections to boost your vitamin B12 levels at the start of treatment, the cyanocobalamin tablets may start to work within a few days.
Water soluble vitamins, like B12, can be tolerated at higher doses without adverse effects upon the body, and the National Academy of Medicine has not established an upper limit of Vitamin B12 intake.
So does vitamin B12 give you energy? While B12 doesn't directly provide energy, it does give the body the tools it needs to convert food molecules into energy. Getting the recommended daily amount of B12 can therefore help ensure that the body is able to make the energy it needs to do everything you need it to do.
What Abnormal Results Mean. Values of less than 160 pg/mL (118 pmol/L) are a possible sign of a vitamin B12 deficiency. People with this deficiency are likely to have or develop symptoms. Older adults with a vitamin B12 level less than 100 pg/mL (74 pmol/L) may also have symptoms.
If a person does not get enough vitamin B-12, a doctor may suggest supplements containing more than the daily recommended dose. The body does not store excess vitamin B-12, so taking extra is not harmful.
In some people, high levels of B12 may cause gastrointestinal problems such as bloating and diarrhea. And if you have high blood pressure or poor cardiovascular health, having too much B12 may further complicate these issues. Pregnant and breastfeeding women may also need to be especially mindful of B12 levels.
“Take water-soluble vitamins on an empty stomach with a glass of water,” recommends Dr. Perez-Gallardo. And since it can be energizing, Dr. Perez-Gallardo says that the best time to take vitamin B12 is in the morning, so it won't affect your sleep.
Oral B12 supplements often contain higher levels than the recommended daily allowance (RDA). The reason for higher amounts is that the body doesn't absorb most of it. For example, if you take a low dose supplement (less than 1-2 mcg), your body absorbs only about half of it.
Generally 120-680 pmol/L.
In contrast to iron deficiency, the prognostic value of B12 and folic acid was not significant. Increased levels of serum cobalamin are associated with malignancies, autoimmune diseases, and renal and liver failure. It is a marker for liver-cell damage, due to release of the vitamin from damaged liver cells.
Stores of vitamin B12 in the body can last around 2 to 5 years without being replenished, so it can take a long time for any problems to develop after a dietary change.
People with vitamin B12 deficiency can have neurological symptoms and/or damage without anemia (lack of red blood cells). General physical symptoms of vitamin B12 deficiency can include: Feeling very tired or weak. Experiencing nausea, vomiting or diarrhea.
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.
Vitamin B12 deficiency can indeed lead to weight gain. But the weight gain is not a direct result of the deficiency. Instead, vitamin B12 deficiency causes lethargy or lack of energy, and in turn, inactivity causes weight gain.
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.
According to health experts at Click Pharmacy, as a general rule of thumb, take your B vitamins in the morning or with a meal. 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.
Vitamin B12 is essential for the production of red blood cells and DNA. It is also essential for the functioning of the nervous system. When your body does not receive enough vitamin B12 you may feel fatigued and tired all the time. It can also lead to weakness.
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].
Interactions between your drugs. No interactions were found between Vitamin B12 and Vitamin D3. However, this does not necessarily mean no interactions exist. Always consult your healthcare provider.