Which Vitamins Should Never Be Taken Together?
Key Takeaways
- Nutrient timing can affect absorption: Some vitamins and minerals may interact with each other depending on when they’re taken.
- Certain combinations are best taken separately: Pairings like iron and calcium or zinc and copper are often spaced out to avoid interference.
- Some nutrients are better taken with food: Fat-soluble vitamins like A, D, E, and K are typically taken with meals that include fat.
- Other nutrients can be taken together: Certain vitamins, such as B vitamins, are often grouped in combined supplements.
- Supplement routines may require planning: Considering spacing and interactions can help support overall nutrient intake.†
Most experts will tell you that a healthy diet should be priority number one when it comes to meeting your nutritional needs. There are some instances when supplementing may be beneficial to boost your intake.
If you’re taking more than one vitamin or mineral each day, you may be wondering which vitamins should not be taken together at the same time.
Because many nutrients interact with one another and affect how well your body can utilize each one, it’s a good idea to pay attention to when you supplement in addition to how much you take.
There are also some nutrients that are better absorbed with a meal, such as fat-soluble vitamins that should be taken with a source of healthy fats, which can affect the time of day you’ll want to take them.
Let’s take a closer look below at vitamins you’ll want to skip taking together, as well as those that complement one another.
What Vitamins Should Not Be Taken Together
Here are nutrient combinations you’ll want to avoid taking together:
Iron and Calcium
Taking calcium and iron supplements together will block some iron from being fully digested, plus it may lead to an upset stomach. While you don’t need to go crazy planning your meals perfectly to avoid this combination, it can be helpful to avoid an iron supplement with a high-calcium meal, such as with milk or leafy greens. Instead, take iron on an empty stomach if possible, or at least separate these supplements by taking one in the morning and the other later in the day.
Vitamin C and Vitamin B12
To help your body use these essential nutrients, space out vitamin C supplements from vitamin B12 supplements by at least 2 hours. Vitamin C can interfere with your ability to absorb B12, so it’s best to take these separately.
High doses of calcium, zinc, or magnesium
Although they work together to support bone health and healthy immune function, these minerals compete for absorption. They may all be combined in a multivitamin, but if you’re taking them individually, it’s best to space them out.
Copper and Zinc
Zinc can interfere with copper absorption, especially if you take high doses every day. Generally speaking, taking large amounts of minerals with other minerals will reduce absorption of both, so try to take them at least 2 hours apart if possible.
How to Help Your Body Absorb Nutrients Effectively
1. Avoid fat-soluble vitamins on an empty stomach
These include vitamins A, D, E, and K, which are absorbed best with some fat (such as olive oil, nuts, seeds, fatty fish, eggs, or avocado). While you may be taking these vitamins together in a multivitamin, if you’re taking individual fat-soluble vitamins, it’s recommended that you space them out.
2. Take multivitamins with a meal to prevent nausea
Many high-quality multivitamins, such as those that are “food-based,” may also require more than one dose in order to help you absorb more of the nutrients.
3. Try a B-complex supplement
B vitamins can be taken together (and may be combined into a “B complex” supplement). B vitamins include thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folic acid (B9), and cobalamin (B12), which can be taken with or without food.
4. Try these vitamin pairs
While there are some vitamins you should avoid taking together, there are others you’ll want to combine in order to support absorption. Pair together iron and vitamin C to help with absorption. Vitamin D and calcium can also be taken together to help with absorption and to support bone health and beyond.
5. Keep antioxidants separate
If you take an antioxidant supplement, take it separately from a multivitamin for the most beneficial effects. Be especially careful about avoiding taking calcium supplements and antioxidant supplements together, since calcium can decrease how the body uses carotenoids like beta-carotene, lycopene, and astaxanthin.
6. Be mindful of medication interactions
Keep in mind that supplements containing vitamins, minerals, and omega-3 fatty acids can also interfere with many common medications, such as blood thinners and thyroid medications. Therefore, talk to your doctor about your supplement routine if you take daily meds.
References:
- Hallberg L, Brune M, Erlandsson M, Sandberg AS, Rossander-Hultén L. Calcium: effect of different amounts on nonheme- and heme-iron absorption in humans. Am J Clin Nutr. 1991 Jan;53(1):112-9. doi: 10.1093/ajcn/53.1.112. PMID: 1984335.
- Herbert V, Jacob E. Destruction of vitamin B12 by ascorbic acid. JAMA. 1974 Oct 14;230(2):241-2. PMID: 4479087.
- Spencer H, Norris C, Williams D. Inhibitory effects of zinc on magnesium balance and magnesium absorption in man. J Am Coll Nutr. 1994 Oct;13(5):479-84. doi: 10.1080/07315724.1994.10718438. PMID: 7836627.
- Hoffman HN 2nd, Phyliky RL, Fleming CR. Zinc-induced copper deficiency. Gastroenterology. 1988 Feb;94(2):508-12. doi: 10.1016/0016-5085(88)90445-3. PMID: 3335323.
- Dawson-Hughes B, Harris SS, Lichtenstein AH, Dolnikowski G, Palermo NJ, Rasmussen H. Dietary fat increases vitamin D-3 absorption. J Acad Nutr Diet. 2015 Feb;115(2):225-230. doi: 10.1016/j.jand.2014.09.014. Epub 2014 Nov 17. PMID: 25441954.
- Teucher B, Olivares M, Cori H. Enhancers of iron absorption: ascorbic acid and other organic acids. Int J Vitam Nutr Res. 2004 Nov;74(6):403-19. doi: 10.1024/0300-9831.74.6.403. PMID: 15743017.
- Christakos S, Dhawan P, Porta A, Mady LJ, Seth T. Vitamin D and intestinal calcium absorption. Mol Cell Endocrinol. 2011 Dec 5;347(1-2):25-9. doi: 10.1016/j.mce.2011.05.038. Epub 2011 Jun 1. PMID: 21664413; PMCID: PMC3405161.
- Biehler E, Hoffmann L, Krause E, Bohn T. Divalent minerals decrease micellarization and uptake of carotenoids and digestion products into Caco-2 cells. J Nutr. 2011 Oct;141(10):1769-76. doi: 10.3945/jn.111.143388. Epub 2011 Aug 24. PMID: 21865558.
- Singh N, Singh PN, Hershman JM. Effect of calcium carbonate on the absorption of levothyroxine. JAMA. 2000 Jun 7;283(21):2822-5. doi: 10.1001/jama.283.21.2822. PMID: 10838651.
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