Do Vitamins Break a Fast? The Best Supplements for Fasting

Do vitamins actually break a fast?

And what about those other supplements in the kitchen cupboard? Are they ok to take while intermittent fasting?

Well, whether vitamins or supplements break a fast isn't a simple yes or no answer. It really depends on what type of fasting you're doing and which supplements you choose. Some vitamins and supplements will absolutely break your fast, while others won't affect your fasting state at all.

We're going to sort through the confusion and tell you exactly which vitamins you can take during your fasting window and which ones to save for your feeding window.

Short answer: It depends.

Most vitamins won't break a fast if you're taking the right type. The problem is that many vitamin supplements contain small amounts of carbs, sugar, fillers or additives that might break your fast. Those vitamin gummies on the shelf might taste brilliant, but they're high in sugar and will definitely break your fast.

To get the benefits of fasting, you want to avoid foods and beverages that have calories or might trigger an insulin response. Some vitamins are best absorbed with food, which creates a bit of a dilemma when you're fasting. The key is knowing which vitamins you can take during fasting and which ones are better saved for when you're ready to break your fast.

Fat-soluble vitamins may not technically break a fast, but they need to be taken with food for proper absorption. Water-soluble vitamins can be taken during your fasting window since they dissolve in water and don't require food for absorption.

If you're within your fasting window, there are still plenty of vitamins you can take without worrying about breaking your fast.

These include all B vitamins (B1, B2, B3, B5, B6, B7, B9, B12) and vitamin C. Water soluble vitamins are excreted throughout the day through your urine, so it's important to drink plenty of water when taking these supplements. Since they are not stored by the body, they need to be consumed daily.

Water-soluble vitamins can be taken during fasting since they dissolve in water and don't need food for absorption. Your body doesn't store these vitamins, so taking water-soluble vitamins during your fasting period helps maintain adequate vitamin levels.

Note: Some people find that B vitamins might cause stomach upset when taken on an empty stomach. If this happens, try taking them with a large glass of water.

Here's where things get a bit tricky. Most multivitamins contain both water soluble and fat soluble vitamins, which creates a timing dilemma. A multivitamin that contains no added sugar, artificial sweeteners, fillers or unnecessary preservatives won't technically break your fast, but you might be wasting some of the nutrients.

The fat soluble vitamins (A, D, E, K) in your multivitamin need food for proper absorption. Taking your multivitamin during fasting means these vitamins won't be absorbed effectively. You're basically flushing money down the toilet.

Your best bet? Save your multivitamin for when you break your fast with a meal containing healthy fats. If you really want to take something during your fasting window, look for a supplement that focuses mainly on water soluble vitamins like B complex and vitamin C.

Folic acid (Vitamin B9) is a water soluble vitamin that's safe to take during fasting. Like other B vitamins and Vitamin C, it doesn't require food for absorption and contains no calories. This makes it perfectly fine for your fasting window.

Probiotics are those helpful little bacteria that support your digestive system. The good news? Zero calorie probiotic capsules won't break your fast since they don't contain any calories or macronutrients.

Here's the thing though - fasting already does brilliant things for your gut microbiome all on its own. Research shows your gut bacteria get a proper reset during fasting periods. Will adding a probiotic capsule make things even better? The jury's still out on that one, but since a zero-calorie capsule won't hurt your fast, we will leave it up to you!

Want to know what might break your fast? Here's what to avoid during a fast:

These are basically sweets with added vitamins. Vitamin gummies are often filled with sugar and calories that will spike your insulin and break your fast. If you're taking these, swap them for capsules or tablets without added sugars.

Many liquid vitamin supplements are sweetened with sugar, honey or fruit concentrates. These will definitely break your fast and kick you out of ketosis if that's your goal.

Most chewable vitamins contain sugar or artificial sweeteners that might break your fast. Even sugar free versions often have ingredients that could affect your fasting state.

The purpose of protein powders is typically to help your muscles recover post workout, which is impossible to do without energy (calories). Many protein powders will contain 20+ grams of protein, 5+ grams of carbohydrates and at least 100 calories, which will certainly break a fast.

Branched chain amino acids, or BCAAs, are amino acids including leucine, isoleucine and valine. One of the primary benefits of intermittent fasting is autophagy, or your body's efforts to clean out its cells. Even when BCAA supplements don't contain calories, they've been shown to cause an insulin response that prevents autophagy from happening.

Fish oil might be a healthy fat, but it's still fat. Each capsule contains around 5 to 10 calories. For a strict fast aimed at autophagy, these calories are enough to break your fast. Save your omega 3 supplements for when you break your fast with a meal.

Those fizzy vitamin tablets might seem harmless, but they're fast breakers in disguise. Effervescent vitamins like Berocca almost always contain sweeteners (like aspartame or sorbitol) and flavourings that can trigger an insulin response, even if the calorie count looks low on the label.

Stick to plain vitamin capsules or tablets if you want to maintain your fast.

Kombucha might be trendy and packed with probiotics, but it's fermented tea that contains loads of sugar and calories. Even the "low sugar" versions will break your fast.

Save this gut-friendly drink for your eating window.

This popular supplement is a tricky one. Pure creatine monohydrate is technically calorie free, but it can cause an insulin response in some people. Most commercial creatine powders are mixed with sugars like dextrose to help absorption, which definitely breaks a fast.

Best to save your creatine for your eating window to be safe.

Here's a recap of which supplements to take and which to avoid during your fasting window.

Timing is everything when it comes to taking vitamins during fasting. Get this wrong and you might break your fast or waste your vitamin intake.

Water-soluble vitamins are your friend during fasting. B vitamins and vitamin C can be taken anytime. Since these dissolve in water, they won't break your fast and your body can absorb them without food.

It's best to take these in the morning if you're doing intermittent fasting to support your energy levels throughout the day.

Morning Fasters (8pm to 12pm fast):

• Take B vitamins around 10am with plenty of water
• Vitamin C can be taken anytime during your fasting window
• Avoid taking B vitamins too late as they might affect sleep

Evening Fasters (12pm to 8pm fast):

• Take water soluble vitamins in the early afternoon
• This timing supports energy when you need it most

Fat soluble vitamins need food. Vitamins A, D, E and K are best absorbed with food containing healthy fats. Take fat soluble vitamins with your first meal to maximise absorption. This is when your body can properly use these nutrients.

Breaking Your Fast Protocol:

• Take vitamin D with foods containing fat like eggs or avocado
• Vitamin K works well with leafy greens and healthy oils
• Consider taking these with your largest meal of the day
  
  

This is the most common fasting protocol. Take water soluble vitamins during your 16 hour fasting window and fat soluble vitamins with your first meal.

During longer periods of fasting, taking water soluble vitamins becomes more important to support your body's functions. Take B vitamins and vitamin C every 24 hours during extended fasting.

On your two low calorie days (500 to 600 calories), stick to water soluble vitamins to avoid using up your calorie allowance. On normal eating days, take your full vitamin regimen.

Most multivitamins contain both water and fat soluble vitamins, which creates a timing challenge. Here's what to do:

Option 1: Take your multivitamin with your first meal to get proper absorption of fat soluble vitamins

Option 2: Split your vitamins. Take water soluble ones during fasting and fat soluble ones with meals

Option 3: Choose a multivitamin that focuses mainly on water soluble vitamins for fasting windows

If you work out during fasting, take B vitamins 30 to 60 minutes before exercise. These support energy metabolism when your body is switching fuel sources.

B vitamins can be stimulating, so avoid taking them within 4 hours of bedtime. This is particularly important if you're sensitive to supplements.

If vitamins make you feel sick during fasting, try taking them with more water or split the dose throughout your fasting window.

The short answer? It depends on what you're taking and why you're fasting.

Taking water soluble vitamins probably won't affect your results. Your main focus is creating a calorie deficit, and a zero calorie vitamin capsule won't interfere with that.

Be more strict about what you take. Stick to truly zero calorie, zero insulin response supplements. Even small amounts of certain compounds can interrupt the cellular cleanup process you're trying to achieve.

Vitamins become more important to prevent deficiencies. Focus on water soluble vitamins and electrolytes to support your body through longer fasting periods.

Here's the thing - people take vitamins for different reasons. Some want to maintain energy levels during fasting. Others are concerned about nutrient gaps in their regular diet. If you're already taking vitamin supplements, there's no need to completely overhaul your routine just because you're fasting.

The key is being smart about timing and choosing vitamins that won't interfere with your fasting goals. Most water soluble vitamins are needed for proper body function, so don't sacrifice vital nutrients in the name of being "perfectly" fasted.

Taking vitamins during fasting doesn't have to be complicated.

Water-soluble vitamins can be taken during your fasting window without worry.

Fat-soluble vitamins are best saved for when you break your fast with healthy foods containing fat.

The key principles:

• Water soluble vitamins (B complex, vitamin C) are fine during fasting
• Fat soluble vitamins (A, D, E, K) need food for absorption
• Avoid vitamin gummies and sweetened supplements
• Pure form vitamins are less likely to break your fast
• Timing matters for maximising both fasting benefits and vitamin absorption

Remember, the best fasting protocol is one you can stick to long term. If taking certain vitamins helps you maintain your energy and makes fasting easier, that's more important than being perfectly strict about every little thing.

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It is not intended to treat or diagnose symptoms, and is definitely not intended to be misconstrued for medical advice. We always advise you seek the advice of a trained professional when implementing any changes to your lifestyle and dietary habits.

We do, however, recommend seeking the services of a trained professional who questions the conventional wisdom to enable you to become the best version of yourself.