What Vitamins Shouldn’t Be Taken Together?

Quick Health Scoop

• What vitamins you shouldn’t take together really depends on the type of nutritional supplement.
• Some individual vitamin supplements work best with or after a meal (especially ones containing fat), while others should be taken on an empty stomach.
• Certain dietary supplements (such as mineral supplements) shouldn’t be taken together often because they affect the absorption of one another such as Iron and Calcium.

Health experts agree that the best way to get all the essential nutrients you need lies in healthy eating. Consuming a wide variety of nutrient-dense foods will deliver the vitamins and minerals your body needs to thrive. In fact, every system in your body depends on these nutrients to function properly and maintain good health. But for a variety of reasons, many people fall short when it comes to consistently eating a nutritious, balanced diet. So, they turn to dietary supplements to make up for any shortfall.

In fact, supplementing can help increase your intake of a specific vitamin or mineral.

However, if you take more than one supplement, you might wonder, “What vitamins shouldn’t be taken together?” On the flip side, you might also wonder, “What vitamins can I take together?”

Vitamins play a vital role in keeping us healthy, but should they be taken at the same time? Keep reading to learn what vitamins shouldn’t be taken together —and which ones pair well together.

Can You Take All Your Vitamins At The Same Time?

Vitamins are classified into two main categories: water-soluble and fat-soluble vitamins. As a quick refresher, your body needs 13 essential vitamins for normal cell function, growth, development, and they help support overall health. [1]†

The body stores fat-soluble vitamins—including Vitamin A, Vitamin D, Vitamin E, and Vitamin K—in fatty tissue. Because of this, fat-soluble vitamins are absorbed more easily in the presence of dietary fat, so avoid taking them on an empty stomach. Instead, take a fat-soluble vitamin with a meal or snack, making sure it includes a healthy fat (such as avocado, eggs, fatty fish, olive oil, nuts, or seeds).

As the name indicates, a water-soluble vitamin is found in the water-based tissues of the body. The body does not store water-soluble vitamins—including the B Vitamin family and Vitamin C—and any “leftovers” leave the body through the urine. [2] The B vitamins include the following:

• Vitamin B1 (Thiamin)
• Vitamin B2 (Riboflavin)
• Vitamin B3 (Niacin)
• Vitamin B5 (Pantothenic Acid)
• Vitamin B6(Pyridoxine)
• Vitamin B7 (Biotin)
• Vitamin B9 (Folate/Folic Acid)
• Vitamin B12 (Cobalamin)

What Vitamins Should You Avoid Taking Together?

Certain supplements seem to work against each other when paired up. What vitamins shouldn’t be taken together? 

Iron and Calcium

For example, if you take an Iron supplement to support healthy cognitive function and a Calcium supplement to support bone health at the same time, this will result in decreased Calcium absorption in the intestine. Why? Because these two minerals both compete with one another for absorption in the body.[3] In fact, it’s probably best if you take a Calcium supplement at a different time from your multivitamin (that may contain Iron) or an Iron-rich meal.[4] Ditto if you’re taking an Iron supplement—avoid taking it with Calcium-rich foods (like milk or leafy greens).†

High doses of Iron and Zinc

If you take a high dose Iron supplement along with a Zinc supplement on an empty stomach, this may block Zinc absorption. [3] It is never recommended to take an iron supplement on an empty stomach.

High doses of Calcium, Zinc or Magnesium

As noted above with the Iron and Calcium, Calcium will compete for absorption with other minerals. Since Calcium can affect how your body absorbs Iron, it can also affect the absorption of Zinc and Magnesium, too. [4] While it’s OK to take them together in a multivitamin (which typically contains smaller doses of these minerals), it’s best to space out these supplements if you’re taking them individually.

Copper and Zinc

If you’re taking a Zinc supplement, don’t take it at the same time as Copper, Iron, or Phosphorus supplements. Instead, space them out a couple of hours apart. [5] In general, large amounts of minerals taken at the same time as other minerals will reduce absorption of each other.

What Vitamins Should You Consider Taking Together And Why?

B Vitamins

Often recognized as a group, the B vitamins often work together in the body and are often found together in the same food. The B vitamins perform unique, important functions, like converting food into energy, and is foundational to the whole body health. As a supplement, these are vitamins that can be taken together, either as an individual nutrient (such as Vitamin B12) or combined into a B Complex supplement. †

Vitamin C and Zinc

According to recent research, “The prevalence of inadequate nutrient intakes that support the immune system (Vitamin A, C, D, E) remain substantial and some are higher (Vitamins C, D, and Zinc) than previously reported.” [6] That’s why you might commonly see Vitamin C and Zinc together in immune supplements. †

Iron and Vitamin C

Vitamins that can be taken together also include Iron and Vitamin C, since Vitamin C increases the absorption of non-heme Iron (Iron from plant-based sources). [3]

Best Ways To Take Different Vitamins

When it comes to vitamins that complement each other, there’s a lot to consider. Take water-soluble vitamins, like B Vitamins and Vitamin C, with a glass of water and a meal or snack. The when is up to you. For some people, this might work best first thing in the morning while eating breakfast or at lunch to help them build a routine and remember to take their supplements.

Keep in mind that some vitamin supplements and mineral supplements may interfere with certain medications, including antibiotics, blood thinners, blood pressure medications as well as others. Taking them together may affect nutrient absorption and may cause side effects and other issues. Therefore, always talk with your healthcare provider before taking any supplements—especially if you regularly take medication.

Finally, take your dietary supplements according to the dosage instructions and pay attention to what you eat. Taking an excessive amount of a supplement may result in a large dose of a specific nutrient, which is not recommended. Discuss your routine with your doctor to ensure you are taking the right dosage for your lifestyle.

What About Multivitamins?

Many health experts say it’s often less about what time you take supplements and more about whether you’re taking them with a meal and/or with water. For most supplements—including your daily multivitamin—you should take them with your largest meal of the day, which is probably lunch or dinner. Ideally, the meal should contain some healthy fat (think avocado, eggs, fatty fish, or nuts) to allow optimal absorption of the fat-soluble vitamins. The most important point to remember? Take your daily multivitamin supplement with food and water.†

And what about a prenatal vitamin? Since a prenatal supplement is also a multivitamin, take it with a meal. Why? Because the vitamins and minerals (especially those fat soluble vitamins like Vitamins A, D, E, and K and Omega-3s like DHA) absorb best with a meal that contains some fat. Since it helps to take your vitamins at the same time every day to establish this healthy habit, take them at breakfast, lunch, or dinner--whatever works best for you.

How Can Supplements Help Me Support My Health?

Supplements can support your nutritional needs, from A to Zinc. While they don’t replace healthy eating, they do help fill in any nutrient gaps to support your health and well-being. To ensure you’re choosing the right supplement to meet your individual needs and health goals, first talk to your doctor. Then, make sure you choose a high-quality supplement from a trusted brand like Nature Made®. Grounded in decades of research, we deliver high-quality, science-backed products—and we’ve been an industry leader since 1971.†

Bottom Line

The body stores fat-soluble vitamins—including Vitamins A, D, E, and K—and they’re absorbed more easily in the presence of dietary fat, so avoid taking them on an empty stomach. Take them with a meal or snack that includes a healthy fat. Water-soluble vitamins—including the B Vitamin family and Vitamin C—are found in the water-based tissues of the body and should be taken with water and food. What vitamins shouldn’t be taken together? Mineral supplements—often because they affect the absorption of one another. Other individual nutrient supplements (like B Vitamins) work well together in the body. Your best bet is to follow the directions on the supplement package. And talk to your doctor about your supplement routine, asking about any questions or concerns.

Continue to check back on the Nature Made blog for the latest science-backed articles to help you take ownership of your health.

† These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.

References 

1. National Center for Complementary and Integrative Health. “Vitamins and Minerals.” February 2018. Accessed on: August 31, 2022. https://www.nccih.nih.gov/health/vitamins-and-minerals

2. “Vitamins.” February 26, 2021. Accessed on: August 31, 2022. https://medlineplus.gov/ency/article/002399.htm

3. Oregon State University Linus Pauling Institute. “Iron.” May 2016. Accessed on: August 31, 2022. https://lpi.oregonstate.edu/mic/minerals/iron#nutrient-interactions

4. Mayo Clinic. “When should I take calcium supplements? Does the timing matter?” September 12, 2020. Accessed on: August 31, 2022. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/calcium-supplements/faq-20058238

5. Mayo Clinic. “Zinc Supplement (Oral Route, Parenteral Route).” July 1, 2022. Accessed on: August 31, 2022. https://www.mayoclinic.org/drugs-supplements/zinc-supplement-oral-route-parenteral-route/precautions/drg-20070269

6. “Inadequacy of Immune Health Nutrients: Intakes in US Adults, the 2005–2016 NHANES.” Accessed on: September 1, 2022. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7352522/