Is it possible to take too many vitamins?

Imagine this scenario. It’s Saturday afternoon. You watch as your friend pulls out her pill organizer to prepare for the week ahead. It has morning, midday and evening slots for each day of the week that she carefully fills with pills.

You take a closer look and you realize the pill bottles aren’t prescription medications but vitamins, dozens of them. You wonder if she needs to take all those vitamins and if it’s possible to take too many?

This scenario is more common than you think. From time to time, I encounter a patient who has a laundry list of vitamins they’re taking. The main question I have for them is do they really need to take them? Sometimes people take vitamins out of habit and they aren’t even aware if they’re helping.

When I think about vitamins, I think supplements. The vitamins should be supplementing something that’s missing from your diet. If your nutrition is bad or you have a condition or disease that prevents your body from absorbing certain nutrients, then yes – you need to take supplements. But if your gut is working well and you’re eating a balanced diet, you’re probably getting all the nutrients your body needs and shouldn’t have to take a supplement. 

So how do you know if you need to take a supplement?

First, take a close look at your diet. Everything we need is going to be provided in what we find in food. That’s actually the best source. Ask yourself – Am I eating a combination of protein, carbohydrates and fat? Does my diet include a variety of fruits and vegetables? Am I a vegetarian or vegan?

Raise your awareness of what you’re eating and make changes to your diet that you can sustain. I tell my patients who only like five vegetables that they need to become super adventurous with eating. You have to find other vegetables you like and find other ways to get your nutrients in. Remember, supplements are not replacements for food.

If you’re a vegan or a vegetarian who doesn’t eat animal products, you do need a supplement for B12, which you can only get in animal products. You can do this by eating fortified foods or by taking a vitamin. For these patients, I also check their iron, calcium and zinc levels. Those are available in grain form and in fruits and vegetables, but aren’t as easily absorbed as with animal products. If these levels are low, supplements may be needed.

If you have a poor diet and are having trouble changing it, supplementation may be necessary.

I take vitamins every day, should I stop?

I usually recommend an elimination process. Why don’t you go off one and see if you feel any difference. If you feel the same, consider no longer taking it.

Can taking too many vitamins impact my health?

It’s possible. Once the human body uses the vitamins and minerals it needs, the rest is excreted or stored.

There are some supplements that can cause harm, so you have to be aware of what you’re taking. There are water-soluble and fat-soluble vitamins. Water-soluble vitamins have less tendency to cause harm because we can flush them out of the system with water, while fat-soluble vitamins are absorbed slowly and stored longer. Unless you’re working out all the time and using those fat stores, there’s more of a chance to build up toxic levels.

Vitamin K, which is found in leafy greens, plays a role in your body’s blood clotting process. People who are on blood thinners need to have stable vitamin K levels. A sudden increase in vitamin K through diet or a supplement can decrease the effectiveness of blood thinners.

We also need to keep an eye on vitamin B6. Too much vitamin B6 may cause neurological symptoms, like tingling in the feet and numbness.

In older adults, we need to watch kidney function. As a natural progression of aging, the kidneys don’t filter as well, so it wouldn’t be wise to take more than the recommended daily allowance of dietary supplements. Less is more in this case.

I’ve been thinking about supplementation. How can I start?

I recommend talking to your doctor before taking supplements beyond a daily multivitamin. If you get the OK from your doctor, look for vitamins from a whole food source. For example, vitamin C that comes from oranges and beta carotene that comes from a vegetable. It will say on the bottle non-GMO, organic, gluten free, soy free and whole food source. Try to avoid synthetic vitamins made in a lab.

Supplements can be costly and may be a huge financial burden. Moderation is key. Only take what you need to make up for what’s missing in your diet.

Dr. Renee Miranda is an integrative medicine physician at The Ohio State University Wexner Medical Center.


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