Diabetes is a chronic disease that affects how the body processes blood sugar (glucose). There are two main types of diabetes: type 1 diabetes is an autoimmune disease where the body attacks the cells in the pancreas that make insulin, a hormone needed to regulate blood sugar levels. Type 2 diabetes is more common and occurs when the body becomes resistant to insulin or doesn’t make enough insulin. Both types of diabetes result in high blood sugar levels which can damage organs, blood vessels and nerves over time if not properly managed.
There are a number of medications and lifestyle changes that can help manage diabetes, and some people look to vitamins and supplements as an additional way to improve blood sugar control. One vitamin that has gained interest is B12, an essential vitamin that plays a role in nerve function and red blood cell formation. This article will examine the link between vitamin B12 and diabetes and whether B12 supplements are beneficial for people with diabetes.
The role of B12 in the body
Vitamin B12, also known as cobalamin, is a water-soluble vitamin that is naturally found in many foods including meat, fish, eggs and dairy products. It can also be taken as a supplement. Vitamin B12 plays several important roles in the body:
– It is needed to form red blood cells and for proper nervous system function. B12 helps make the protective covering of nerves, called the myelin sheath. Without adequate B12, the myelin sheath deteriorates, leading to nerve damage and neurological problems.
– B12 is necessary for proper DNA synthesis and cell division. This is especially important in tissues that are constantly regenerating like bone marrow, skin and the lining of the gut.
– Vitamin B12 is a cofactor for several enzymatic reactions. Enzymes are proteins that speed up chemical reactions in the body. B12 helps enzymes convert certain amino acids and fats into energy.
– B12 may benefit heart health by improving blood flow, reducing inflammation and lowering homocysteine levels. Elevated homocysteine is a risk factor for heart disease.
Without enough vitamin B12, people can develop pernicious anemia, a condition where the body cannot make an adequate amount of healthy red blood cells. Symptoms of vitamin B12 deficiency include fatigue, brain fog, memory problems, depression, neurological damage, headache and pale skin.
The link between B12 and diabetes
So how does B12 relate to diabetes? There are a few key points of intersection between vitamin B12 and diabetes:
– Nerve damage is a common complication of poorly controlled diabetes. High blood sugars can damage the myelin sheath around nerves over time, causing diabetic neuropathy. Given B12’s role in maintaining myelin, it is thought that B12 deficiency could worsen neurological complications in diabetics.
– Metformin, a commonly prescribed medication for type 2 diabetes, has been shown to reduce B12 absorption in some patients over long term use. Metformin interferes with calcium dependent absorption of the vitamin.
– People with diabetes who take metformin may need to supplement with B12 to prevent deficiency, especially the elderly who already have trouble absorbing B12.
– Diabetics are more prone to anemia, or having too few red blood cells. Since B12 is needed to produce red blood cells, anemia in diabetes may be exacerbated by low B12 levels.
– Diabetes causes inflammation and oxidative stress throughout the body. As an antioxidant, B12 supplementation may help reduce some of this excess inflammation.
– High blood sugars can damage blood vessels over time, leading to atherosclerosis and cardiovascular issues. By improving blood flow and lowering homocysteine, B12 may benefit heart health in diabetics.
Research on B12 and diabetes
So is there solid evidence to support B12 supplementation in diabetics? Here’s a look at some of the key research:
– Multiple studies have shown that metformin use is associated with reduced B12 levels. Up to 30% of those taking metformin long term can develop B12 deficiency. The longer someone uses metformin, the more likely they are to have low B12.
– In a study of 140 diabetics, 47% of those taking metformin had B12 deficiency compared to only 6% not taking the medication. The metformin group was also more likely to have anemia.
– Several randomized controlled trials found that giving B12 supplements to those taking metformin improved B12 status and reduced homocysteine levels. In one trial, those who received B12 had less neuropathy progression compared to placebo group.
– A study in rats with induced diabetes found that B12 supplementation reduced oxidative stress markers and apoptosis (cell death) in the retina and nerves, possibly protecting against diabetic retinopathy and neuropathy. Rats given B12 also had improved pancreatic beta cell regeneration and function.
– Multiple studies show an association between low B12 levels and cognitive decline. This may be particularly relevant for elderly diabetic patients at risk of dementia.
– Research on whether B12 supplements directly improve diabetes control has been mixed. Some studies have found benefits like improved nerve conduction while others showed no difference compared to placebo. Larger clinical trials are still needed.
Metformin and vitamin B12 deficiency
The strongest link between diabetes and B12 deficiency involves the use of metformin. Metformin reduces how much B12 is absorbed in the gut and increases its excretion.
With long term metformin use, B12 levels can drop low enough to cause neuropathy, anemia and cognitive problems in some patients. That’s why it’s recommended for anyone on metformin, especially the elderly, to have periodic screening for B12 deficiency.
Supplementing with B12 is often necessary for those taking metformin long-term to overcome the depletion effects of the medication. Either high dose B12 tablets or B12 injections can be used to restore normal levels.
Patients and doctors should be aware that numbness or tingling in the hands and feet may be an early sign of B12 deficiency, not just diabetes neuropathy. Catching and correcting low B12 can help minimize nerve damage.
Are B12 supplements beneficial for diabetics?
Based on the research, getting adequate B12 appears important for many people with diabetes, particularly those taking metformin. However, there are still open questions about whether B12 supplements should be given broadly to all diabetics.
Here are some key considerations on who may benefit from B12 supplementation:
– Diabetics taking metformin, especially over many years, are at high risk of B12 deficiency and should have levels monitored and supplemented as needed. For those with deficiency symptoms, B12 therapy is strongly recommended.
– Patients with poorly controlled diabetes who already have neuropathy or anemia may benefit from B12 supplementation to support neurological and red blood cell function.
– Elderly diabetic patients could benefit from B12 to reduce dementia and stroke risk. As we age, B12 absorption decreases and low levels are more common. Small studies suggest B12 supplementation can slow cognitive decline in the elderly.
– Vegetarians and vegans with diabetes need to be aware of increased B12 deficiency risk since animal products are the main dietary sources. Supplements are essential for these groups.
– There is still no conclusive evidence that B12 improves diabetes control or lowers blood sugars in those not already deficient. More research is needed before universal B12 supplementation.
– High doses of B12 may interact with other medications or medical conditions, so supplements should be discussed with a doctor.
For many diabetics, correcting any B12 deficiency is likely beneficial. But there is no need for most diabetics to megadose B12 if they don’t have a true deficiency. As with any supplement, more is not necessarily better and excessive doses can potentially cause harm.
Recommendations for getting enough B12 with diabetes
The National Institutes of Health sets the recommended daily allowance for B12 at 2.4 mcg for adults. Here are some tips for getting adequate B12 levels as a diabetic:
– Eat B12-rich foods like meat, eggs, dairy, fish and shellfish. Those who eat little or no animal products should consider B12 fortified foods or supplements.
– If taking metformin, get B12 levels tested regularly, at least every 1-2 years. fast.
– Work with your doctor to determine if you need a B12 supplement or injections to overcome deficiency. Typical doses are between 500-1000 mcg per day.
– Look for signs of B12 deficiency like fatigue, memory loss, tingling/numbness and take action quickly if they occur.
– When supplementing B12, go for cyanocobalamin or methylcobalamin forms which are readily available and absorbed.
– For those on metformin who are not B12 deficient, a daily multivitamin with B12 or weekly B12 tablet may help maintain healthy levels.
– Try combining B12 with other essential nutrients like vitamin D, magnesium, omega-3s that may also benefit diabetes and nerve function.
– If you have gastric conditions like celiac disease or Crohn’s, absorption of B12 from foods may be reduced, requiring supplements.
– Discuss your diet and medication regimen with your doctor and determine an individualized plan for meeting your vitamin B12 needs.
Food sources of B12 for diabetics
You can obtain vitamin B12 from both animal foods and fortified foods:
Animal sources
– Liver and other organ meats – extremely high in B12
– Fish like salmon, tuna, cod – good sources, especially when cooked
– Shellfish such as clams, oysters and mussels
– Red meat – beef, lamb and pork provide B12
– Poultry like chicken and turkey
– Eggs and dairy products like milk, cheese and yogurt
Fortified foods
– Nutritional yeast – often fortified with B12
– Non-dairy milks – many brands fortify soy, almond, coconut or oat milks with B12
– Some breakfast cereals contain added B12
– Meat substitutes and veggie burgers – check labels for B12
– Meal replacement shakes and protein bars with B12
When choosing animal products, go for grass-fed, pasture-raised and wild caught whenever possible. Avoid processed and factory farmed meats. Prepare seafood and eggs thoroughly to reduce risk of infections.
For vegetarians and vegans, combining different fortified foods throughout the day can help meet needs. Supplements are also commonly required on plant-based diets to prevent B12 deficiency.
Supplements and injections
There are two main forms of B12 found in supplements – cyanocobalamin and methylcobalamin.
Cyanocobalamin is typically better absorbed but must be converted to methylcobalamin – the active form used in the body. Methylcobalamin skips this conversion step but may be more expensive. Ultimately, both forms are effective at increasing B12 levels.
The body can only absorb about 1.5-2.5 mcg of a B12 dose at a time via passive diffusion. This is why standard daily B12 supplements provide more than the RDA – to ensure adequate absorption.
With deficiencies, very high dose B12 given through injections or sublingual tablets that dissolve under the tongue may be used. These can deliver B12 more efficiently through active transport instead of just passive diffusion.
Speak to your doctor about whether high-dose B12 therapy is appropriate and which route of administration makes the most sense based on the severity of your deficiency.
Oral B12 tablets
Chewable or sublingual B12 tablets ranging from 500-5000 mcg are available over the counter. The body can absorb about 1% of the B12 dose this way through passive diffusion. This is more than enough for maintenance in most people but higher doses may be preferred in diabetics on metformin. Timed-release B12 preparations may maximize absorption throughout the day.
Sublingual tablets
Sublingual tablets dissolve under the tongue rather than being swallowed. Holding B12 tablets under the tongue allows direct absorption into the bloodstream, bypassing digestion. About 10-30% of the dose is absorbed this way versus only 1% for standard oral tablets. Sublingual forms delivering 1000-5000 mcg are a convenient option for increasing B12 levels quickly.
Patch
B12 transdermal patches worn on the skin provide a continuous release of B12 over 24 hours. Like sublingual forms, patches avoid digestion and liver metabolism. Absorption may be up to 20% of the dose. Patches are easy to use though some people can develop skin irritation from the adhesive.
Nasal gel
Using B12 gel squirted inside the nose is another method that enables direct absorption into the bloodstream. Nasal sprays may utilize 1000-5000 mcg doses of B12. Not all of the gel is fully absorbed but nasal delivery is still highly effective and convenient.
Injections
Intramuscular B12 injections allow nearly complete absorption of very high doses, bypassing limitations of passive diffusion. Injections of 1000 mcg daily or weekly are commonly used to treat deficiency. Effects are seen quickly with injections but they do require administration by a medical professional.
For severe B12 deficiency, practitioners may opt for an initial loading dose between 1000-5000 mcg given daily for 1-2 weeks to rapidly boost B12 levels. This switches to a monthly maintenance dose of 1000-3000 mcg. Injections can help replenish B12 stores faster than oral supplements.
Side effects and precautions
Vitamin B12 is considered very safe, even at high doses. No toxic upper limit has been set. Side effects are rare but can include:
– Itching, rash or swelling with injections
– Metallic taste
– Nausea or diarrhea
– Anxiety or insomnia if taken in extremely large doses
B12 supplementation is considered safe in pregnancy and breastfeeding. Babies born to vegetarian/vegan mothers should be monitored for B12 status.
Due to potential impact on absorption of other nutrients, it is best not to take B12 supplements at the same time as:
– Folic acid supplements
– Iron supplements
– Vitamin C high dose supplements
B12 has potential drug interactions with chloramphenicol, proton pump inhibitors, H2 blockers, metformin, colchicine, and certain anticonvulsants.
Those with Leber’s disease, a rare genetic eye condition, should avoid supplemental B12 which may exacerbate vision loss.
As with any medical therapy, it is wise to start supplementation under supervision of a doctor to ensure safety and efficacy.
Testing B12 levels
Doctors can check biomarkers of B12 status including:
– Serum B12 level – Low levels under 200 pg/mL indicate deficiency. Borderline deficiency is between 200-350 pg/mL.
– Methylmalonic acid – This compound is high when B12 levels are insufficient.
– Homocysteine – High homocysteine indicates a potential B12 deficiency.
– Red blood cell count and hemoglobin – Anemia can signal low B12.
If symptoms of B12 deficiency are present, doctors may recommend trying B12 supplements directly rather than waiting for confirmation from blood tests. Oral therapy is considered safe and the benefits tend to outweigh any risks when deficiency is suspected.
Periodic monitoring of B12 status is wise for those with increased risk like the elderly, diabetics on metformin, strict vegetarians, those with gastric disorders and pregnant/nursing mothers. Catching a deficiency early and promptly correcting with supplementation minimizes any potential complications.
Conclusion
Vitamin B12 plays important roles in the functioning of nerves, blood cells and DNA synthesis. Diabetics are at higher risk of B12 deficiency, especially when taking metformin long-term or if they follow a strict vegetarian or vegan diet.
Research shows that low B12 levels are linked with increased neuropathy, anemia, cognitive decline and heart disease – all critical concerns for diabetics. Studies confirm metformin reduces B12 absorption in many patients over years of use.
There is solid evidence that supplementing can help reverse B12 deficiency in those taking metformin. This may help safeguard neurological health. Routine screening of B12 status is recommended for diabetics on metformin, with supplementation as needed to maintain healthy levels.
The impact of B12 supplements on diabetes outcomes is still unclear for those without existing deficiency. More research is underway to determine if B12 therapy should be given more broadly to all diabetics.
In summary, ensuring adequate B12 consumption from foods and/or supplements is likely beneficial as part of a comprehensive diabetes management plan. Work with your healthcare provider to determine if you need your B12 levels monitored or require supplementation for optimal health.