The best time to take fat-soluble vitamins such as vitamins D, A and K is with a meal that contains fats.
You should take water-soluble vitamins such as vitamins C, B12 and B6 on an empty stomach in the morning.
Take multivitamins or prenatal vitamins with a meal or snack with fat and a glass of water.
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If you’re taking multiple vitamins and supplements, knowing how to time each dose can be challenging. Now is the best time to take them and why it matters.
Why timing matters
You may want to take vitamins and supplements at certain times of the day based on their effects, says Dimitar Marinov, MD, an assistant professor at the Medical University of Varna, Bulgaria.
Important: While the time of day doesn’t change how effectively your body absorbs supplements, whether you take them with meals or not does matter. Some vitamins, such as B and C, are best taken on an empty stomach, while others, such as vitamins A and K, should be taken with foods containing fats for proper absorption.
The best vitamins to take on an empty stomach
You should take water-soluble vitamins and minerals on an empty stomach because your body can absorb and metabolize them more easily, says Alana Kessler, a registered dietitian and nutritional consultant in New York City.
Water-soluble vitamins dissolve in water and contain vitamin C and all B vitamins. You should also take these vitamins with a full glass of water to break them down for absorption, Stephenson says.
Because these vitamins are most effective when taken on an empty stomach, it’s best to take them in the morning, Kessler says.
B vitamins in particular have been shown to boost energy and mood in people who are deficient in them. A 2020 review found that deficiencies in B and C vitamins, iron and magnesium can cause fatigue, and supplementation can help.
General advice: Some people are more sensitive to vitamins and find that water-soluble vitamins, such as vitamin C, upset their stomach. If this is the case for you, it’s okay to take these vitamins with food, Stephenson says. It reduces their absorption, but only by a small amount.
Other vitamins that are best taken on an empty stomach include:
The best vitamins to take with a meal
You should take fat-soluble vitamins with meals or snacks that contain fat, such as avocado, egg yolks, or olive oil, for proper absorption.
Taking these vitamins with food ensures optimal release of bile and pancreatic enzymes in the stomach that are necessary for the absorption of fat-soluble vitamins, Marinov says.
Fat-soluble vitamins include:
For some people, it makes the most sense to take these vitamins with a meal, such as lunch or dinner, but you don’t necessarily have to, Stephenson says. Foods that contain some fat, such as hummus or a handful of nuts, can help break down these vitamins.
Other supplements to take with food include:
Calcium carbonate. This is because the stomach acid produced when you eat helps your body absorb this type of calcium. Calcium citrate, on the other hand, can be taken with or without food, so check the label to see what kind of calcium your supplement contains.
Multivitamins. These contain both water-soluble and fat-soluble vitamins, so take them with food to ensure that the fat-soluble vitamins are absorbed.
Magnesium. Taking magnesium on an empty stomach has a laxative effect and can cause diarrhea.
When should you take prenatal vitamins?
Prenatal vitamins usually contain both water-soluble and fat-soluble vitamins in one tablet. The best time to take prenatal vitamins can vary based on your individual health factors, so be sure to discuss this with your doctor. They can also upset your stomach, so taking them with food can help.
“Because the risk of stomach upset is higher during pregnancy, I recommend taking prenatal vitamins with food, a small snack with some fat is sufficient,” says Stephenson. “This may be the best way to keep the vitamin low, absorb the fat-soluble vitamins optimally and only minimally affect the absorption of the water-soluble vitamins.”