We’re going to answer that question right away so you don’t have to wait for the answer. Yes, all B vitamins are water-soluble vitamins.

What exactly does that mean? We’re going to specifically address the letter vitamins in this blog, but first, let’s address a point of differentiation.


Water-Soluble Vitamins vs. Fat-Soluble Vitamins—What’s the Difference? 

Did you know that vitamins can be water-soluble or fat-soluble? And if you’re thinking, so what? Or who cares? You may be saying to yourself “I’ve got a good vitamin regimen going, and I’m not planning to stop taking a vitamin because it’s one or the other.”

We understand. You’re wondering what difference it makes to you. In today’s blog, we’re going to explain the differences and further explain why knowing and understanding them will help you make better choices in terms of how and when you take your vitamins.

So, here’s the first thing you need to know. All eight of the B vitamins and vitamin C are water-soluble. These four vitamins—A, D, E and K—are fat-soluble.

The main differences between water-soluble and fat-soluble vitamins are this: how they dissolve and are absorbed by your body and how they are stored.

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Let’s start with fat-soluble vitamins. Fat-soluble vitamins are similar to oil in that they don’t dissolve in water. Instead, they are best absorbed when accompanied by some fat. That’s why experts will suggest you take fat-soluble vitamin supplements with a well-balanced meal that contains some fat (preferably the “good” fats—mono- or poly-unsaturated fats versus saturated or trans fats). Taking them with fat allows your body to better absorb their benefits.

Fat-soluble vitamins are transported through the small intestines and then indirectly distributed through your bloodstream. But fat-soluble vitamins stick with you—when it comes to storage.

Here’s what we mean by that. Your body stores fat-soluble vitamins in your liver and your fatty tissues, until it is ready to use them. That’s an important fact to know because your body can accumulate toxic levels of fat-soluble vitamins over time, potentially putting your health at risk. And while this is not a common problem, it is a possibility and is one reason why you should not pop these pills above what it is known as the tolerable upper level (UL) for a vitamin—at least certainly not without the recommendation from, and consultation with, your doctor.

VIDEO: How can you correct a B12 deficiency?


The Properties of Water-Soluble Vitamins

On the other hand, water-soluble vitamins dissolve, as the name suggests, in water. The body makes use of water-soluble vitamins very differently than it does fat-soluble vitamins. It doesn’t store up water-soluble vitamins like a squirrel gathering nuts for winter.

In fact, water-soluble vitamins are quickly absorbed into your tissues and are ready for immediate use by your body. You’ve likely heard it said that you can’t get too much vitamin C because your body will just pee out what it doesn’t need. (That’s the non-scientific way of saying that your body will flush out excess water-soluble vitamins—yes, the B vitamins too!—through your urine.)

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But that can lead to a whole other set of issues to consider. Because your body doesn’t store these water-soluble vitamins, you’ll need to self-replenish, through foods or vitamin supplements to make sure your body remains sufficient or at optimal levels.

At the same time, you don’t want to overdo your vitamin B or vitamin C intake—which is generally not an issue from food alone. Do you sense an important tip about that coming a little later on in this blog?


Does Water-Solubility Determine When to Take Your Water-Soluble Vitamins

There are a lot of things to consider when it comes to what time of day you should take your vitamin supplements. Some supplements shouldn’t be taken at the same time (for example, some experts suggest that taking Vitamin B-12 with vitamin C might reduce the available amount of C in your body. A two-or-more hour separation between the two should take care of that issue.) And some drugs, like metformin, may interfere with your body’s ability to absorb B-12.

This doctor has some interesting advice on when you should take your vitamins. It turns out it’s not as much about whether the vitamins are water- or fat-soluble because as he explains, “it’s less about the time of day and more about syncing the habit with your eating and drinking schedule.”

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The advice from some is for water-soluble vitamins to be taken on an empty stomach with a full glass of water to increase absorption. But others advise that you can take water-soluble vitamins with or without food. Some people complain of nausea or stomach issues with vitamin C; if that’s the case, it’s probably better to take it with food.

And remember to discuss your vitamin supplement regimen (along with the medications you’re taking) with your doctor and ask your pharmacist about potential interactions.


How Water-Solubility Determines the Dose

Here are two ways in which water-solubility could determine the dose: 1) don’t take more than you need because it will be excreted out and 2) be sure that you regularly take your water-soluble vitamins so that your body consistently has those nutrients available for use.

If you want to understand what the government recommends you take daily, read more here. But what is as important, if not more, than taking the “right” amount, is understanding what your body has.

BLOG: Can You Get Too Much Vitamin B12?

By that we mean, know your numbers. Even if you were able to keep track (no easy feat) of how much vitamin B12, for example, you were getting each day from your combined food and supplements, you still want to know what your status is. That’s the test of whether you’re getting the most from your vitamins. At OmegaQuant, we offer an at-home urine test for Methylmalonic Acid, a vitamin B12 status marker.

By collecting a urine sample with this collection kit, then sending it in to our lab, you’ll get an indication in the form of a report from us that will let you know whether you are low in this critical nutrient. From there, you’ll get some advice on next steps.


What Are Water-Soluble Vitamins Good For?

Let’s do a quick review of some of the reasons why you need your B-vitamins and vitamin C. To read more about the B’s, check out this blog.

  • B1 (thiamine)—like all B vitamins, this one helps metabolize your food into the accessible energy that your body needs to function. It also helps your heart operate properly and may help improve high blood sugar and insulin levels in people with diabetes.
  • B2 (riboflavin)—this B vitamin protects an important antioxidant in your eyes, known as glutathione, thereby supporting eye health. There’s some research that has shown it may help lower migraine frequency in those who suffer from those debilitating headaches.
  • B3 (niacin)—it plays a role in cell signaling and producing and repairing DNA. Other potential benefits may include support for brain function and skin cell protection from the sun.
  • B5 (pantothenic acid)—one of its functions is to manufacture sex and stress-related hormones in the adrenal glands. Plus, your cells need it for growth, development and proper function.
  • B6 (pyridoxine)—this B vitamin is involved with over 100 enzyme reactions related to metabolism. Other potential benefits may include brain health support, potentially as a mood improver, cognition strengthener and helper in reducing the risk of Alzheimer’s.
  • B7 (biotin)—this B is thought by some experts to promote healthy hair, nails and skin. For a basic, but “must-have,” benefit, B7 works with enzymes to take the carbs, fats and protein you eat and convert them it into energy for your body.
  • B9 (folic acid or folate)—this one is a must for pregnant women to reduce the risk of neural tube birth defects such as spina bifida. But it’s also important throughout life for healthy cell growth and function and protein metabolism.
  • B12 (cobalamin)—Known as the “energy” vitamin, B12 turns food into usable energy. It also helps with DNA synthesis and keeping your blood and nerve cells healthy. You need it too during pregnancy for maternal health and the health of your fetus.
  • Vitamin C—this antioxidant fights off free radicals to protect your cells and support your immune system. It may also play a role in supporting heart and eye health.


Too Much of a Good Thing? Or Not Enough?

If you consume (including supplements) too much of the water-soluble vitamins, is it dangerous? Let’s put it this way—at the very least, it’s not a good idea.

Even though your body takes in what it needs and pushes the rest of the water-soluble vitamins out, high doses of vitamin C can cause nausea and diarrhea. As for vitamin B, this article explains that, in general, many of the eight B vitamins are generally non-toxic, and for some (like B5, B7 and B12) no tolerable UL has been established; for other B vitamins, high doses can result in diarrhea (B5) or neurotoxicity (B6).

BLOG: Does Vitamin B12 Give You Energy?

On the other hand, you could end up with a water-soluble vitamin deficiency. For example, too much vitamin B9 could mask the symptoms of a vitamin B12 deficiency in older people.

Bottom line: With so many variables, testing your vitamin levels or status can help reassure you that you’re truly getting the right amount for your body. Although OmegaQuant does not currently offer a test to measure vitamin C, there are blood tests that do measure those levels. Testing can be a relatively simple way to stay on top of your numbers. Read more about our B12 test here.

VIDEO: What OmegaQuant’s Vitamin B12 Test Measures and Why

These statements have not been evaluated by the Food and Drug Administration. This test is not intended to diagnose, treat, cure, prevent or mitigate any disease. This site does not offer medical advice, and nothing contained herein is intended to establish a doctor/patient relationship. OmegaQuant, LLC is regulated under the Clinical Laboratory improvement Amendments of 1988 (CLIA) and is qualified to perform high complexity clinical testing. The performance characteristics of this test were determined by OmegaQuant, LLC. It has not been cleared or approved by the U.S. Food and Drug Administration.

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