Are Multivitamins Necessary? And Other Frequently Asked Questions

“I don’t take vitamins — isn’t it better just to get your nutrients from food?”

My attempt to justify why I don’t pop a multivitamin every day is what started this whole series. My co-workers’ reactions were immediate and hysterical, as if they were shocked I hadn’t collapsed from rickets in front of them.

But that sparked a conversation, and we realized we really didn’t know much about vitamins. So I took our questions to UVA pharmacist Donna White.

What exactly are vitamins and minerals?

They’re basically nutrients that are required in small amounts for essential functions in our bodies. These functions maintain:

• Bone health
• Teeth
• Structural health
• Blood cells

Why do we need vitamins and minerals?

If we don’t get adequate amounts, we can get diseases like scurvy, which comes from a lack of vitamin C. We don’t see that anymore because we can easily get vitamin C through food sources. And there are actually foods that are fortified with vitamins that aren’t as easy to get.

For example, milk and cereal are fortified with vitamin D, but you can also get it from even small exposure to sunlight, as little as 15 minutes three times a week.

We see a lot of ads for multivitamins. Do we really need those?

A balanced diet provides us with the appropriate vitamins and minerals. The problem is whether we’re eating what’s necessary to obtain those minerals and vitamins. You should have three servings of fruits and five servings of vegetables per day, and pick bright colors. But in our daily routines, we might not be getting all of that.

There are some instances where some vitamins are needed in higher amounts. For example, higher doses of folic acid in pregnancy prevent birth defects.

Also, say somebody is on a very restricted caloric diet for weight loss or other reasons. They would certainly benefit from a multivitamin. And certain diseases cause absorption issues.

But for the regular person who should be eating a healthy diet, you can get what you need from food.

If you do take a multivitamin, does it matter if it’s name-brand or generic?

Yes and no.

We know brand names have been well studied and their ingredients have been verified in studies. Generics are OK as long as they’re verified by the USP (U.S. Pharmacopeial Convention.)

I think most places where you buy vitamins, like pharmacies and grocery stores, are going to be OK. A health food store may have some vitamins that aren’t USP branded.

What does “fat-soluble” and “water-soluble” mean?

Fat-soluble vitamins (A, D, E and K) are stored in the liver, whereas water-soluble vitamins (C and the B vitamins) pass through the system and leave through the kidneys.

You’ve probably heard the phrase: If you’re taking large doses of water-soluble vitamins, you have expensive urine. And with water-soluble vitamins, if you have poor renal function, anything that is excreted through urine could build up in the body.

Your liver is a great detoxifier, so you do process and excrete fat-soluble vitamins. But the process is different, so if you have something you’re taking too much of, your body has less ability to clear it.

Is it possible to get too much of a vitamin?

It shouldn’t be much of an issue if it’s just your food source plus a multivitamin. If you’re taking multivitamins and then additional singular vitamins on top of that, that could be a concern.

In particular, it’s the fat-soluble vitamins that can be problematic — in very very large doses — because they stay in your system and can become toxic.

If you were taking high, high doses of vitamin C, which is water-soluble, that could lead to kidney stones. The requirement for vitamin C is around 100 milligrams a day. But when people purchase Vitamin C for colds or whatever reason, the doses are 500 or 1,000 milligrams. When you get to doses above 2,000 milligrams, which is not that many if someone is thinking they’ll cure their cold by popping them in, there’s a risk of kidney stones.

Do fish oil supplements have enough mercury to cause harm?

They do not. There are several studies that have looked at that. Fish oil goes through a purification process. In some studies, there may have been the slightest amount of mercury. Some people tout that fish oil supplements are actually safer than eating the fatty fish, with regards to mercury.

Back to vitamin C. Is there any truth to the claim it can cure a cold?

No, not really.  If you’re susceptible to six colds a year and you took a high dose of vitamin C every day for a year, you might shorten the length of the cold from 10 days to nine days. And that’s if you’re taking it every single day.

So it really hasn’t borne out. And then you could get into the issues with kidney stones.

What about protein powder? Do people doing strength training need extra protein?

Proteins aren’t vitamins or minerals; they’re amino acids. You have to be careful about them, too. Increasing your protein like that has wear and tear on your kidneys. It’s not unusual to find someone who is young and who exercises a lot and also has a big body build, and they have increasing levels of muscle breakdown in their system.

Most of us need about a gram of protein per kilogram (2.2 pounds) of weight per day.

If you’re taking vitamin supplements and are on medication, do you need to worry about interactions?

There are certainly drugs that are affected by taking vitamins or minerals. It works both ways. Some drugs cause a depletion of vitamins and minerals. For example, Metformin, which is for diabetes, can cause a decrease in B12.

There are some antibiotics that, if they are given closely with a multivitamin with minerals, the antibiotic doesn’t work as well. That’s why you’ll see on the bottle to take on an empty stomach.

Most of the time, I think physicians are not telling patients to take a multivitamin. People get the idea from outside resources or seeing it on TV.  But also patients will come into the pharmacy and ask about multivitamins. When we ask patients, “Are you taking anything over-the-counter?” we ask specifically about multivitamins and minerals, because a lot of times patients don’t consider those medications.

I think it would be good to always bring up any change in your medication, including vitamins, with your doctor.