TL;DR: Taking vitamins on an empty stomach can lead to poor absorption, nausea, or other digestive issues, especially with fat-soluble vitamins like A, D, E, and K, which need food to be properly absorbed. Water-soluble vitamins like B12 and C are less dependent on food but may still cause stomach discomfort for some. Eating even a small amount of food, especially with some fat, can improve absorption and reduce side effects. While vitamins can help fill nutrient gaps, they are not a substitute for a balanced diet, which provides a variety of nutrients that work together to support overall health.
What Happens If You Take Vitamins Without Eating?
Taking vitamins without eating can affect how well your body absorbs them. Some vitamins are better absorbed when taken with food, while others may be absorbed differently depending on what you eat.
For example, if you take vitamin D3 supplements without food, you may absorb less of the vitamin than when you take it with a low-fat meal.1 Calcium supplements can make it harder for your body to absorb iron from food when taken together.2 This means that if you're trying to get enough iron in your diet, it might be better to take calcium supplements at a different time than when you eat foods high in iron.
Can You Throw Up From Taking Vitamins on an Empty Stomach?
Yes, you can throw up from taking vitamins on an empty stomach.3
Taking certain vitamins without food might upset your stomach and make you feel sick, leading to nausea and vomiting. Some vitamins may have added ingredients or "fillers" that cause these problems.
It's important to note that taking large amounts of some vitamins or supplements, like arginine, can also cause stomach issues, especially when taken all at once.
Other side effects of taking vitamins on an empty stomach may include:
- Diarrhea
- Nausea
- Rash
- Stomach discomfort
Why Do You Feel Sick After Taking Vitamins on an Empty Stomach?
Taking vitamins on an empty stomach might make you feel sick because some can upset your stomach. This is especially true for certain vitamins or supplements containing added ingredients.
Another reason you might feel sick after taking vitamins on an empty stomach is that they can change how your stomach works. For example, if you drink water with copper in it on an empty stomach, your stomach takes longer to empty. This delay in stomach emptying could make you feel nauseous or sick. So, taking vitamins with food is often better to help prevent these uncomfortable feelings.
Why Should You Take Vitamins With Food?
Taking vitamins with food is important because it can help your body absorb them better. Some vitamins, especially fat-soluble ones like vitamins A, D, E, and K, need fat to be absorbed effectively. When vitamin D is taken with a meal that contains fat, the absorption increases significantly. This means your body can use the vitamins more efficiently when consumed with food. Additionally, taking vitamins with meals can help reduce stomach upset and nausea that sometimes occurs when taking vitamins on an empty stomach.
Other benefits of taking vitamins with food include:
- Improved absorption of nutrients
- Reduced risk of stomach discomfort
- Better overall nutrient intake
- Lower rates of vitamin deficiency in the body
Are There Any Vitamins You Can Take on an Empty Stomach?
Some vitamins can be taken on an empty stomach, while others are better absorbed with food. Water-soluble vitamins, like vitamin C and all B vitamins, don't necessarily need food to be absorbed and can be gentle on the stomach. Fat-soluble vitamins, like vitamins A, D, E, and K, require fat for proper absorption, so it's better to take them with a meal that includes healthy fats.
However, taking certain vitamins on an empty stomach, especially ones with higher doses, might cause mild discomfort or nausea. Always follow the supplement's instructions or consult your healthcare professional for personalized advice.
Do You Need To Eat a Full Meal When Taking Supplements?
You don't necessarily need to eat a full meal when taking vitamin supplements. Still, eating some food, especially with fat, can help your body absorb certain vitamins better.
For example, taking vitamin D with the largest meal of the day can support its absorption and healthy vitamin D levels in the blood.4 Taking it with a meal containing fat supports absorption even more than taking it with a fat-free meal. This means that even a small amount of food with some fat can help your body better use your vitamin supplements. However, the type of fat (whether it's mostly monounsaturated or polyunsaturated) doesn't make a difference in how well the vitamin is absorbed.
What Happens If You Take Vitamins Instead of Eating?
Taking vitamins instead of eating regular meals can lead to nutritional gaps and health issues. While vitamins can help fill in some nutrient deficiencies, they are not a complete substitute for food.5
A balanced diet provides a variety of essential nutrients that work together in the body, which vitamins alone cannot fully replace.6 For example, vitamins like B12 and D are essential but best absorbed with other nutrients in whole foods. Relying solely on vitamins may lead to deficiencies in protein, fiber, and other vital components necessary for good health.
Additionally, multivitamins and mineral supplements can have an appetite-related effect, potentially leading to lower hunger levels in some individuals.7 However, this does not mean that they should replace meals. It is essential to maintain a well-rounded diet to ensure overall health and proper nutrient intake. While vitamins can support your diet, they should not be seen as a replacement for eating nutritious foods.
The Bottom Line
Taking vitamins without food is often less effective and may cause unpleasant side effects like nausea or upset stomach. Fat-soluble vitamins (A, D, E, and K) need dietary fat for proper absorption, while even water-soluble vitamins like B12 and C can sometimes irritate an empty stomach. Pairing vitamins with even a light snack containing some fat can support adequate absorption and minimize discomfort. However, supplements are just that—supplements. They are not a replacement for a balanced diet full of whole foods, which provide a variety of nutrients that work together to support overall health. Combine your vitamins with a nutritious, well-rounded diet to get the most from your vitamins and support your health and well-being for the long term.†
References:
- https://pubmed.ncbi.nlm.nih.gov/22190928/
- https://pubmed.ncbi.nlm.nih.gov/33758936/
- https://pubmed.ncbi.nlm.nih.gov/21749321/
- https://pubmed.ncbi.nlm.nih.gov/20200983/
- https://pubmed.ncbi.nlm.nih.gov/25027766/
- https://pubmed.ncbi.nlm.nih.gov/26134111/
- https://pubmed.ncbi.nlm.nih.gov/17977472/
† These statements have not been evaluated by the Food and Drug Administration (FDA). This product is not intended to diagnose, treat, cure, or prevent any disease.