The "negatives" of vitamin B12 generally fall into two categories: the consequences of a deficiency and the potential side effects of high-dose supplementation, though the latter is rare and usually mild.
Safety and side effects
Taking doses of vitamin B-12 might cause: Headache. Nausea. Diarrhea.
You should be able to get all the vitamin B12 you need by eating a varied and balanced diet. If you take vitamin B12 supplements, do not take too much as this could be harmful. Taking 2mg or less a day of vitamin B12 in supplements is unlikely to cause any harm.
While research shows that high vitamin B12 levels don't directly damage healthy kidneys, elevated B12 often serves as an indicator of underlying kidney dysfunction.
Vitamin B12 is a nutrient that supports healthy nerve and blood cells. It also helps you make DNA, your body's genetic material, that are present in every cell. B12 also helps prevent megaloblastic anemia, which is a blood condition that can make people feel tired and weak.
Vitamin B12 Deficiency Has Nothing To Do With Weight Gain
There is very little evidence to suggest that vitamin B12 affects the process of gaining or losing weight, despite the numerous techniques involved. Most of the evidence supporting this claim comes from a few observational studies.
Vitamin B12 does a lot of important things for your body. It helps create your DNA and red blood cells, for example. Your body also needs B12 for the development of your central nervous system (your brain and spinal cord).
The foods highest in Vitamin B12 are animal products, with clams and liver (beef, lamb) being exceptionally rich sources, often providing several hundred percent of the daily value in a single serving, alongside seafood like mussels, sardines, and salmon, dairy, eggs, and fortified cereals and nutritional yeast for vegans.
Symptoms of vitamin B12 or folate deficiency
Dairy Milk
In addition to B12, milk is an excellent source of calcium and is rich in protein, both of which are needed for bone and muscle health. Best for: People who consume animal products, tolerate dairy well, and are looking for a high-protein drink.
B12 deficiency can trigger specific food cravings, most notably for meat, fish, or eggs, as the body seeks animal-based sources to replenish the vitamin, especially in those on vegetarian/vegan diets or older adults. While cravings for sugary or salty foods can also signal general B-vitamin issues, the distinct urge for protein-rich animal products is a key indicator, but professional testing is crucial for confirmation.
A lack of vitamin B12 can cause neurological problems, which affect your nervous system, such as: vision problems.
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.
In conclusion, our results show that lower vitamin B12 was associated with insomnia symptoms and sleepiness in specific groups of participants. However, further research with objective measurements of sleep is crucial to assess the relationship between sleep and vitamin B12.
Research shows that low B12 could influence fat metabolism because a lack of B12 may hinder your body's ability to burn fat effectively, potentially leading to weight gain.
High B12 levels can cause the following symptoms:
Cutaneous manifestations associated with vitamin B12 deficiency are skin hyperpigmentation, vitiligo, angular stomatitis, and hair changes. A diagnosis of vitamin B12 deficiency is often overlooked in its early stages because these signs are not specific to vitamin B12 deficiency alone.
Dietary folate, vitamin B6, and vitamin B12 were significantly associated negatively with hypertension, indicating that these nutrients might have a protective effect against hypertension in United States adults.
Some studies have also linked riboflavin deficiencies to ophthalmological findings such as blurred vision. Most recently a study by Zhao et al, in 2022 reported on the possible association between riboflavin deficiencies and night-time blindness.
Animal products – meat, fish, dairy and eggs – are great sources of Vitamin B12. Consider beef, liver, sardines, salmon, eggs, milk, cheese, clams and tuna. If you don't eat animal products, you may have a more challenging time getting enough vitamin B12.
Foods or drinks to avoid
May improve brain health
One study found that low B12 levels, even within the lower normal range, can in part lead to poor memory performance. Vitamin B12 is an important nutrient for the neurons in your brain. Brain atrophy, which refers to the loss of neurons in your brain, is connected to memory loss and dementia.
Two large eggs provide a significant portion of your daily Vitamin B12, roughly 1.4 to 2.7 micrograms, depending on size, with almost all of it found in the yolk, contributing around 15-46% of the Daily Value (DV) for adults, making eggs a good source of this essential nutrient for red blood cell formation and nerve function, though absorption from eggs might be lower than meat, notes Healthline, EggInfo, and Australian Eggs.
Organ meats
An animal's liver and kidneys tend to have the largest amounts of vitamin B12. One study showed that beef organ meats had more vitamin B12 than pork organ meats. A 3-ounce serving of these organ meats contains: Cooked beef liver: 70.7 micrograms.