Vitamin B12 and vitamin D are two essential nutrients that play important roles in the body. Vitamin B12 is important for neurological function, DNA synthesis, and red blood cell formation. Vitamin D helps regulate calcium absorption and promotes bone health. Many people take vitamin B12 and D supplements, either individually or in combination. This raises the question: can you take vitamin B12 and vitamin D together?
The short answer is yes, vitamin B12 and vitamin D can be taken together safely. In fact, there are several benefits to combining these two vitamins into one supplement or multivitamin. When taken together at appropriate doses, vitamin B12 and D can work synergistically to support energy levels, brain health, bone health, immune function, and more.
Vitamin B12 overview
Vitamin B12, also known as cobalamin, is a water-soluble B complex vitamin. It plays a vital role in many bodily processes. Here are some of vitamin B12’s main functions and benefits:
- Supports red blood cell formation – Vitamin B12 is necessary for the production of red blood cells and prevention of anemia.
- Maintains neurological health – B12 is needed to synthesize neurotransmitters and myelin, which protects nerve fibers.
- Boosts energy levels – Vitamin B12 helps convert carbohydrates into glucose, giving the body energy.
- Supports DNA synthesis – B12 is required for DNA replication and production.
- Promotes heart health – Studies show B12 may lower homocysteine levels, reducing heart disease risk.
- Supports mood and cognitive function – Vitamin B12 impacts the production of serotonin, dopamine, and other mood-regulating neurotransmitters.
The recommended daily intake of vitamin B12 for adults is 2.4 mcg. Vitamin B12 is naturally found in animal foods like meat, eggs, milk, cheese, and fish. It can also be taken as an oral supplement or injection.
People at risk for B12 deficiency include:
- Vegans or vegetarians
- The elderly
- Those with gastrointestinal disorders like celiac disease or Crohn’s disease
- People taking heartburn medications long-term
- Those who have undergone certain surgeries like gastric bypass
Deficiency symptoms include fatigue, weakness, constipation, loss of appetite, weight loss, neurological changes, and megaloblastic anemia.
Vitamin D overview
Vitamin D is a unique vitamin because it functions as a prohormone. Vitamin D helps regulate calcium and phosphorus absorption to support bone health and density. Some additional benefits of vitamin D include:
- Strengthens bones – Vitamin D improves calcium absorption for bone mineralization.
- Boosts immunity – Vitamin D activates immune responses to viruses and bacteria.
- Supports muscle function – Vitamin D receptors are present in muscle tissue and help with contraction.
- Reduces inflammation – Vitamin D exhibits natural anti-inflammatory properties.
- Protects cognitive health – Vitamin D may help prevent dementia, Alzheimer’s disease, and depression.
- Promotes cardiovascular health – Vitamin D is linked to lower blood pressure, cholesterol, and stroke risk.
The recommended daily vitamin D intake is 600-800 IU (15-20 mcg) per day. Good food sources include fatty fish, egg yolks, fortified dairy and juices, beef liver, and mushrooms. Vitamin D synthesis from sunlight is limited based on geography, skin pigmentation, and sunscreen use.
Those at risk for vitamin D deficiency include:
- People with limited sun exposure
- Individuals with darker skin tones
- Infants who are exclusively breastfed
- Older adults
- People who are overweight or obese
- Those with gastrointestinal absorption issues
Low vitamin D is associated with soft, brittle bones, muscle weakness, fatigue, mood changes, impaired wound healing, and an increased risk of autoimmune disorders.
Benefits of taking vitamins B12 and D together
Combining vitamin B12 and vitamin D into one supplement or multivitamin provides synergistic effects. Here are some of the evidence-based benefits of taking B12 and vitamin D together:
Supports energy levels
Vitamin B12 and vitamin D both help fight fatigue and boost energy in the body. Vitamin B12 aids in red blood cell formation, which increases oxygen transport. Vitamin D supports muscle function and nerve conduction. Together, these vitamins can enhance daily energy levels.
Strengthens bones
Vitamin D promotes calcium absorption and bone mineral density, while vitamin B12 is needed to produce osteoblasts, which are bone-forming cells. Consuming adequate amounts of both vitamins provides better bone support than either alone.
Boosts mood
Vitamin B12 participates in neurotransmitter synthesis, and vitamin D is linked to serotonin activity. By taking B12 and vitamin D, you can optimize levels of brain chemicals that regulate mood, focus, stress response, and cognition.
Supports brain health
Vitamin B12 nourishes the brain and central nervous system. Vitamin D activates neuroprotective compounds in the brain. Together, these micronutrients may prevent cognitive decline, dementia, and Alzheimer’s disease.
Aids muscle function
Vitamin D receptors are found in skeletal muscles and the heart. Adequate vitamin D levels support muscle contraction and cardiovascular function. Vitamin B12 maintains muscle coordination and prevents neurological muscle weakness.
Boosts immunity
Vitamin D enhances innate immunity by modulating the expression of antimicrobial proteins. Vitamin B12 assists in the production of new immune cells. Combining B12 and D provides broader immune system support.
| Benefit | Vitamin B12 Contribution | Vitamin D Contribution |
|---|---|---|
| Energy Levels | Aids red blood cell formation | Supports muscle function |
| Bone Health | Produces osteoblasts | Improves calcium absorption |
| Mood | Synthesizes neurotransmitters | Regulates serotonin |
| Brain Health | Nourishes nervous system | Activates neuroprotective compounds |
| Muscle Function | Maintains coordination | Supports muscle contraction |
| Immunity | Produces immune cells | Modulates antimicrobial proteins |
Are there any side effects or interactions?
Vitamin B12 and vitamin D are considered very safe when taken at appropriate supplemental doses. Since they are both water-soluble vitamins, excess amounts are flushed out in urine rather than stored long-term.
There are no known interactions or side effects from combining vitamin B12 and vitamin D together. Very high doses of either nutrient could potentially lead to adverse effects, such as:
- Vitamin B12 – Diarrhea, blood clots, itchy skin, kidney problems
- Vitamin D – Hypercalcemia, hypercalciuria, kidney stones, nausea, vomiting
However, this requires extremely high supplemental intakes often exceeding 10,000 mcg per day. As long as you avoid excessive doses, vitamin B12 and D can be taken together without concern.
Those with chronic medical conditions should have levels monitored by a doctor when taking new supplements. Individuals taking digoxin (Lanoxin) for heart disease should consult a physician before using vitamin D.
Recommended dosages
The Recommended Dietary Allowance (RDA) for vitamin B12 is 2.4 mcg per day for adults. The RDA for vitamin D is 600-800 IU (15-20 mcg) per day. Most multivitamin supplements contain around 100% of the daily value for both nutrients.
When purchasing individual vitamin B12 and D supplements, aim for a dose within the following ranges:
- Vitamin B12 – 25-100 mcg per day
- Vitamin D – 600-4000 IU (15-100 mcg) per day
Higher doses may be recommended by your doctor for certain medical conditions or recovery needs. For example, older adults often require at least 1000-2000 IU daily of vitamin D.
Look for supplements that use bioavailable, well-absorbed forms like:
- Vitamin B12 – methylcobalamin, adenosylcobalamin, hydroxycobalamin
- Vitamin D – D3 (cholecalciferol)
Avoid taking more than 10,000 mcg (10 mg) per day of either nutrient without medical supervision. Make sure to take B12 and vitamin D supplements with food for optimal absorption.
Who may need extra vitamin B12 and vitamin D?
Certain populations may require increased vitamin B12 and D either from high-nutrient foods or supplements:
Older adults
As we age, vitamin absorption decreases and sun exposure often declines. Older adults often need 2-3 times more vitamin D and extra B12.
Vegans and vegetarians
Plant-based diets provide zero vitamin B12, as it’s only found in animal foods. Vegans/vegetarians also generally eat less D-fortified dairy. Supplements are recommended.
Those with gastrointestinal disorders
Digestive diseases like celiac, Crohn’s, and IBS can impair vitamin absorption. Supplemental B12 and D bypass GI issues.
Obese individuals
The fat cells of those who are obese tend to sequester and hang onto vitamin D, increasing needs. Vitamin D deficiency is common in obesity.
Breastfed infants
Exclusively breastfed babies need supplemental vitamin D beginning within days of birth to prevent deficiency.
Those with certain surgeries
Procedures like gastric bypass can decrease B12 absorption long-term. Additional vitamin D and calcium are also required.
People with darker skin
Higher melanin content can reduce vitamin D synthesis from sunlight. Increased vitamin D intake is recommended.
Sunscreen users
Diligent sunscreen use blocks a significant portion of vitamin D production. Extra vitamin D from diet and supplements is beneficial.
Those with autoimmune disorders
Diseases like multiple sclerosis, rheumatoid arthritis, and lupus often involve vitamin D deficiency. Supplementation may help modulate the immune system.
Conclusion
In conclusion, vitamin B12 and vitamin D can safely be taken together in one supplement, multivitamin, or as individual nutrients. Combining them offers synergistic effects that support energy, brain health, bone density, immunity, mood, and more.
Aim to meet the RDA levels of around 2.4 mcg per day of vitamin B12 and 600-800 IU of vitamin D. Increase your intake if you have a medical condition or factor impacting nutrient status. As long as you avoid excessive amounts, there are no known interactions or side effects with combined vitamin B12 and D supplementation. Those at risk for deficiency will likely benefit from ingesting these two essential vitamins together.