What Vitamins Should Not Be Taken Together?
  /   Dr. John Snow

What Vitamins Should Not Be Taken Together?

Your body wants all the good things. Vitamins, minerals, trace minerals, and nutrients all work together to power your body. While they all provide you with benefits, they may not prefer to work on the same shift. The things that react beautifully with your body may not react beautifully with each other.

Most multivitamin companies keep this in mind when formulating their products. For example, they attempt to adjust the amounts of certain vitamins to promote maximum absorption while reducing the chance for counterproductive interaction between vitamins and minerals, but this isn’t always the case.

There are also a few things that multivitamins may not mention on the label about the best way to take them and what supplements or vitamins you should avoid after you’ve taken them. If you want to get the most out of your vitamins and supplements, you need to understand how your body will best achieve the perfect state of harmony for your wellness products to work properly. 

Don’t Take Vitamins on an Empty Stomach

Many vitamins and supplements contain fat-soluble ingredients. This means that they’re absorbed by the fat in your digestive system and utilized appropriately. For example, if you take your vitamins in the morning on an empty stomach, there is no fat for vitamins like A, E, D, and K to bind to. 

If you’re using these vitamins, you don’t need to use them every day. Fat-soluble vitamins are stored in your tissue and released by your body as they’re needed. It’s possible to build up an unnecessary surplus of fat-soluble vitamins, so if you believe you’re getting plenty of A, E, D, and K from your diet, you don’t necessarily need to ingest more. However, if you’d like to, eat them with a meal and take them once or twice a week. They’ll work much better for you. 

Water-soluble vitamins, like B vitamins, are easily absorbed in water. Take these with a full glass of water before your meal, and take your fat-soluble vitamins after your meal. If you’re using a multivitamin that combines the two, take them in conjunction with a meal and a glass of water. 

Take B12 and Vitamin C Separately

Vitamin C plays many important roles in the body. It’s necessary for immune function, the production of collagen, healing wounds, maintaining healthy teeth and bones; Vitamin B12 helps convert food into energy, assists your body in the manufacturing of red blood cells, and is necessary for the healthy function of the nervous system. 

It can also make it harder for your body to absorb B12. In the end, all you’ll receive a substantial amount of is vitamin C. Wait at least two hours between each supplement. Try taking one with breakfast and one with lunch to assure you’ve given each enough time to be absorbed without interference. 

Calcium Counteracts Iron

Calcium can prevent your body from fully digesting iron. The combination can lead to an upset tummy or a few uncomfortable trips to the bathroom while they’re battling it out in your digestive system. Iron is essential, but it’s better off taken as a solo supplement at a time where the body can properly use it. 

Iron does not need to be taken with food for your body to use, and it has a hard time playing nice with calcium. A beautiful, green salad with a whey protein shake may be your favorite healthy lunch after a trip to the gym, but it’s completely adversarial to iron. It’s better to take iron on an empty salad than to take it with calcium-rich greens and dairy. 

Magnesium, Zinc, and Calcium Together

All three of these minerals are common additions to multivitamin supplements that promote the “all-encompassing, one-a-day” philosophy. The problem with taking magnesium, zinc, and calcium together is that they’re all attempting to be absorbed by your body the same way. They compete, and in that competition, a significant portion of each mineral may be lost. 

If you’re supplementing with all three of these minerals, it’s better to take them in low doses and spread them out over the course of the day. Taking one with each meal will ensure that each mineral has had a chance to absorb before the other is consumed. 

Multivitamins and Omega-3 Supplements May Interfere With Other Medications

If you are taking any medications, ask your doctor before adding any multivitamins or supplements to your routine. Some vitamins, minerals, and Omega-3 fatty acids can affect the way your body absorbs and utilizes thyroid medications, blood thinners, 

Supplements like St John’s wort diminish the effectiveness of many necessary medications. In addition, they can reduce the accuracy of oral contraceptives and create unintended consequences. That’s why many doctors, dentists, and surgeons will ask if you have been taking St John’s wort on the official paperwork you complete before a procedure or treatment begins. 

Even if a new supplement or vitamin-infused green smoothie powder seems innocent enough, you should still double-check that its contents won’t interfere with any medication you need to promote your health and wellbeing. If you can’t get a hold of your doctor, call your pharmacy. In most cases, any available pharmacist will have access to the knowledge you need. 

How to Choose The Right Vitamins

Children should take different multivitamins because the needs of a growing body are different from the needs of a body in maintenance. While certain aspects of choosing the right multivitamin (like quality) for your child, they should be targeted to the needs of the individual.

Every multivitamin that enters your household should be produced by a transparent and reputable brand subject to routine lab tests for quality and consistency. The ingredients list should be free of unnecessary additives. Choose a multivitamin that’s been formulated by medical experts and manufactured in the United States of America. Vitamins manufactured overseas may have different standards for purity and factory sanitation. 

Lastly, you need to make sure the diet is compliant with allergies, lifestyles, and specific needs. If you need a vitamin that’s vegan, non-GMO, gluten-free, or dairy-free, check the label. It’s best not to assume a vitamin meets those needs unless the packaging specifically states it does. 

Multivitamins for Adults

Adult multivitamins often come in varieties for men or women. It’s not necessary to take a gendered multivitamin. The most significant difference between the two is usually the amount of iron. Iron levels tend to go down during menstruation as a direct result of blood loss. 

The idea is that a female-specific multivitamin would provide enough iron to counteract that iron loss, but it isn’t necessary. Instead, it’s introducing more iron to your diet during menstruation in the form of a separate iron supplement or through diet. Beef is an excellent source of iron, but plant-based dieters may prefer a boost of iron for spinach or dark chocolate.

Your doctor may suggest that you take additional supplements to help your body achieve specific goals. Lycopene supplements are often recommended to males looking for a boost to their reproductive health. A pregnant woman’s need for vitamins, minerals, and micronutrients completely changes. In these cases, you should ask your doctor to recommend a multivitamin or supplement specific to your situation. 

Multivitamins for Children

It can be tricky to navigate children’s multivitamins. Children tend to be picky eaters. They’re interested in eating fun colors and dipping everything in ketchup. This makes spinach and healthily prepared proteins a challenge. Children could be missing out on many things vital to their development, like folate and iodine. Children’s multivitamins are designed to supply them with the things they need the most. 

Just watch out for all that sugar. Multivitamins that incorporate sugar and artificial colors to make gummy vitamins more appealing are contrary to the entire purpose of promoting health. Make sure your child’s multivitamins don’t contain more junk than benefits

The Takeaway

Overall, there are a few vitamins that shouldn’t be taken together, and specific vitamins and supplements may interfere with vital medications. Navigating the world of multivitamins can be tricky because many that claim to be all-encompassing will negate themselves. 

Talking to your doctor about your needs will help you find the right combination of vitamins and supplements or the right multivitamin and help you establish a schedule for maximum efficiency and safety.

If you’re seeking a perfectly balanced multivitamin for your child, Hiya has the perfect solution. Our eco-friendly, dairy-free, vegan, gluten-free, and sugar-free chewable vitamins were created by consulting doctors about the nutritional needs of children. The result is a clean multivitamin with an accurate label with none of the junk that many other children’s multivitamins contain. 


Vitamins | MedlinePlus

St. John's Wort StatPearls | NCBI 

Lycopene and Male Infertility | NCBI