Vitamin D is an essential fat-soluble vitamin and found in foods such as eggs, fish and fortified milk. Consuming these foods can help you meet your recommended dietary allowance for this vitamin, which helps to regulate the amount of phosphorus and calcium in your blood, increase your bone density and lower your risk for cancer and high blood pressure. Although vitamin D affects calcium absorption, as reported by the Linus Pauling Institute, it doesn't affect B vitamin or vitamin C absorption.
Vitamin C is an essential water-soluble vitamin found in many fruits and vegetables. This vitamin helps to boost immune function, repair damaged tissues, limit the buildup of free radicals, make collagen and maintain your teeth and bones according to the University of Maryland Medical Center. Cigarette smoking and taking certain medications, including NSAIDs -- anti inflammatories -- and aspirin, can decrease your absorption of vitamin C.
The eight B-complex vitamins include folate, niacin, thiamine, riboflavin, pyridoxine, biotin, cobalamin and pantothenic acid. These water-soluble vitamins help your body turn food into energy and are essential for growth and development, as reported by the American Cancer Society. Consuming whole grains along with a variety of fruits and vegetables can help you meet your recommended intake of the B vitamins, although you need to consume animal products to get your vitamin B-12.
Vitamin B-12 and Vitamin C
Although vitamin D doesn't interfere with the absorption of the B vitamins, vitamin C may interfere with the absorption of dietary vitamin B-12, according to MedlinePlus.com. However, this interaction is easy to avoid by taking your vitamin C supplement two hours before or after consuming foods containing vitamin B-12 or vitamin B-12 supplements.
Do not take megadoses of any particular vitamin or mineral without first consulting your doctor. High doses of individual vitamins or minerals can cause toxicity symptoms, and may interfere with the absorption of certain medications or other vitamins and minerals. Multivitamins offer a balanced way to increase your intake of vitamins and minerals and make it less likely you will become deficient in the nutrients they contain.