Why timing matters
You might 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.
- Magnesium helps with relaxation and sleep so it is best taken at dinner, Marinov says.
- Melatonin also induces sleep so you should take it one to two hours before bedtime.
- Vitamin C can cause indigestion, so some prefer to take it with food to alleviate nausea or constipation.
Best vitamins to take on an empty stomach
You should take water-soluble vitamins and minerals on an empty stomach as your body will more easily absorb and metabolize them, says Alana Kessler, a registered dietitian and nutrition consultant based in New York City.
Water-soluble vitamins dissolve in water and include vitamin C and all B vitamins. You should also take these vitamins with a full glass of water to help break them down for absorption, Stephenson says.
Because these vitamins are most effective when taken on an empty stomach, it is 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, andcan cause fatigue, and supplementation can help.
Other vitamins best taken on an empty stomach include:
- Iron. This is because certain foods, especially dairy, can block the absorption of iron. Vitamin C helps your body absorb iron, so if you are taking an iron supplement, it’s best to combine that with Vitamin C.
- Probiotics. Some types of probiotics, like ones containing Lactobacillus and Bifidobacterium, have been shown to be most effective when taken up to 30 minutes before a meal.
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 the optimal release of bile and pancreatic enzymes in the stomach that are required for the absorption of fat-soluble vitamins, Marinov says.
Fat-soluble vitamins include:
- Vitamin D
- Vitamin E
- Vitamin A
- Vitamin K
For some people, it makes the most sense to take these vitamins with a meal, like lunch or dinner, but you don’t necessarily have to, Stephenson says. Any food with some fat, like hummus or a handful of nuts, can help break down these vitamins.
Other supplements that should be taken 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 be sure to check the label to see the kind of calcium your supplement contains.
- Multivitamins. These contain both water-soluble and fat-soluble vitamins, so take with food to ensure the fat-soluble vitamins are absorbed.
- Magnesium. Taking magnesium on an empty stomach has a laxative effect and may cause diarrhea.
When to take prenatal vitamins
Prenatal vitamins typically include both water-soluble and fat-soluble vitamins in one tablet. The best time to take prenatal vitamins could vary depending on your individual health factors, so discuss with your doctor. They also could upset your stomach, so it may help to take them with food.
“Because stomach upset is more likely in pregnancy, I recommend taking prenatal vitamins with food, a small snack with some fat in it is enough,” Stephenson says. “This may be the best way to keep the vitamin down, optimally absorb the fat-soluble vitamins, and only minimally impact absorption of the water-soluble vitamins.”
The time of day you take supplements is less important than whether or not you take them with food. Take water-soluble vitamins, like vitamin C and folate on an empty stomach, and fat-soluble vitamins, like vitamins A, E, D, and K with food containing fat to ensure proper absorption. You should also take multivitamins or prenatal vitamins with a snack or meal.
Iron Plus Vitamin C – Uses, Side Effects, and More
This medication is an iron supplement used to treat or prevent low blood levels of iron (such as those caused by anemia or during pregnancy). Ascorbic acid (vitamin C) improves the absorption of iron from the stomach.
How to use Iron Plus Vitamin C
Take this medication by mouth, usually once daily or as directed by your doctor.
This medication is best taken on an empty stomach 1 hour before or 2 hours after meals. If stomach upset occurs, you may take this medication with food. Avoid taking antacids, dairy products, tea, or coffee within 2 hours before or after this medication because they will decrease its effectiveness.
Take with a full glass of water (8 ounces or 240 milliliters) unless your doctor directs you otherwise. Do not lie down for at least 10 minutes after taking this medication.
If you are taking a liquid form of this medication, carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. Mix your dose in a glass of water or juice, and drink the mixture through a straw to prevent staining the teeth. If your liquid form is to be given by dropper, the dose may be placed well back on the tongue and followed with water or juice. If your liquid form is a suspension, shake the bottle well before each dose. Use this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time each day.
Constipation, diarrhea, or upset stomach may occur. These effects are usually temporary and may disappear as your body adjusts to this medication.
If any of these effects persist or worsen, contact your doctor or pharmacist promptly.
Iron may cause your stools to turn black, which is not harmful.
If your doctor has prescribed this medication, remember that your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US –
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada – Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Before taking this medication, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before taking this medication, tell your doctor or pharmacist your medical history, especially of: certain metabolic disorders (such as hemochromatosis, hemosiderosis), use/abuse of alcohol, stomach/intestinal problems (such as ulcers, colitis).
If your particular brand of iron supplement also contains folic acid, be sure to tell your doctor or pharmacist if you have vitamin B12 deficiency (pernicious anemia) before taking it.
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
This medication passes into breast milk. Consult your doctor before breast-feeding.
See also How To Use section.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor’s approval.
This product can decrease the absorption of other drugs such as bisphosphonates (for example, alendronate), levodopa, penicillamine, quinolone antibiotics (for example, ciprofloxacin, levofloxacin), thyroid medications (for example, levothyroxine), and tetracycline antibiotics (for example, doxycycline, minocycline). Separate your doses of these medications as far as possible from your doses of this product. Ask your doctor or pharmacist about how long you should wait between doses and for help finding a dosing schedule that will work with all your medications.
This medication may interfere with certain laboratory tests (tests for blood in the stools), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: stomach pain, nausea, vomiting, diarrhea.
Do not share this medication with others.
Laboratory and/or medical tests (such as complete blood count) may be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.
There are many iron supplement products available. Some can be purchased without a prescription. Some brands may also contain other ingredients (such as folic acid, niacin). Consult your doctor or pharmacist for more details.
This medication is not a substitute for a proper diet. It is important to maintain a well-balanced diet. Foods rich in iron include beans, nuts, asparagus, oatmeal, red meat, dried peaches, and pork liver.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.