Taking both vitamin C and D supplements simultaneously may boost immunity, strengthen bones, speed up wound healing, or improve the outcome of cancer treatment.
Vitamins C and D are common ingredients in multivitamins and dietary supplements marketed to support the immune system.
According to Megan Nunn, a community pharmacist in Tennessee with 12 years of experience in medication and vaccination counseling, when combined, these two vitamins offer several health benefits:
Boost immunity
Vitamins C and D both play essential roles in a healthy immune system. When the body lacks either of these vitamins, the risk of illness increases.
These two vitamins complement each other because they boost immunity through different mechanisms. Vitamin C helps fight viral and bacterial infections and reduces inflammation (swelling, redness). It also helps regulate the activity of white blood cells—a key force in the immune response.
Meanwhile, vitamin D helps strengthen the physical defenses of tissues in the body, making it difficult for bacteria and viruses to penetrate. This vitamin also inhibits viral replication, reduces inflammation, and maintains immune system balance, preventing the body from mistakenly attacking healthy cells.
Supplementing with both vitamins C and D simultaneously helps limit the spread of viruses like Covid-19 and reduces the risk of complications.
Bones become stronger.
Low levels of vitamins C and D are associated with low bone mineral density, brittle bones (osteoporosis), and an increased risk of fractures. Supplementing with both vitamins may help increase bone mass by promoting the production of osteocalcin—a crucial protein in bone tissue—instead of reducing the likelihood of fractures.
Vitamins C and D are believed to have a synergistic effect on bone health, meaning that when taken together, they offer better bone protection than when taken individually.
Wounds heal faster
Vitamins C and D play important roles in the wound healing process. Because each vitamin performs a different function, supplementing both simultaneously can help the skin recover more effectively.
Vitamin D helps the skin fight infection and supports the wound healing process, while vitamin C is a powerful antioxidant that helps reduce inflammation and stimulates the body to produce collagen—a protein essential for forming new skin.
Digestive health can be improved.
Supplementing with vitamins C and D helps improve gut health and prevent harmful bacteria from entering the digestive system.
A small study of 23 male athletes showed that using vitamin C, vitamin D, and turmeric helped reduce digestive problems. However, because the study included turmeric, the exact level of benefit from vitamin C or D alone could not be determined.
Cancer treatment outcomes may be more favorable.
In people with a form of acute myeloid leukemia (AML)—a cancer of the bone marrow—vitamin C and D supplementation has been associated with a higher chance of survival.
Taking these two vitamins together is thought to help reduce the risk of serious side effects of cancer treatment, such as bleeding, inflammation, and infection, in AML patients.
Food sources of vitamins C and D
You can increase your intake of vitamins C and D through your diet or supplements.
Vitamin C is abundant in citrus fruits and vegetables. Just half a cup of raw red bell peppers or about 200ml of orange juice provides approximately 100mg of vitamin C.
Healthy adults need approximately 75-120mg of vitamin C per day, depending on gender and whether they are pregnant or breastfeeding; smokers need an additional 35mg/day.
Vitamin D is produced by the body when the skin is exposed to ultraviolet rays from sunlight. Foods rich in vitamin D include salmon, tuna, and cod liver oil. Healthy adults need approximately 15-20 micrograms (mcg), equivalent to 600-800 IU of vitamin D, per day, depending on age.
Note: Please consult with your doctor or healthcare professional before using any vitamins or supplements to ensure maximum safety.