Vitamin D and the B complex are essential vitamins that your body needs regularly. Because they are natural, it is safe to consume them together. In fact, they are both found in the foods you eat, so you are probably consuming them at the same time already.
Vitamin D is a natural nutrient that your body makes when you are exposed to sunlight. If you do not get enough sun exposure or if your diet does not supply enough vitamin D, you can develop osteoporosis. The B complex is actually made up of eight B vitamins. If you are deficient in these vitamins, you can develop anemia, a slow metabolism and have problems with the function of your nervous system. The eight B vitamins are thiamine, riboflavin, niacin, pantothenic acid, biotin, vitamin B-6, vitamin B-12 and folate.
Each vitamin has a recommended dietary allowance, or RDA. This is the amount you need from your diet or supplements to meet the minimum needs in your body. Therefore, your multivitamin should provide at least this amount, with the rest coming from a healthy and balanced diet. The RDA amounts vary depending on your age and gender. The ideal intake for the vitamins is 600 to 800 IU of vitamin D, 1.0 to 1.2 mg of thiamine, 1.0 to 1.3 mg of riboflavin, 14 to 16 mg of niacin, 5 mg of pantothenic acid, 30 mcg of biotin, 1.2 to 1.7 mg of B6, 2.4 mcg of B-12, and 400 mcg of folate or folic acid.
Upper Intake Levels
Many vitamins have upper intake levels, or maximum doses, which you should consume each day from supplements. This prevents toxicity symptoms from developing that could include gastrointestinal problems and other uncomfortable side effects. To avoid toxicity symptoms, do not consume more than 4,000 IU of vitamin D, 35 mg of niacin, 100 mg of biotin or 1,000 mcg of folic acid per day. The other B vitamins do not have upper limits and are not considered toxic in high doses.
Vitamin D and the B complex vitamins are safe to consume together through food or through a multivitamin. If you are on medications, talk with your doctor or pharmacist about any interactions that could affect how your medications function. Certain vitamins can affect the potency of some medications.