Best Time to Take Your Vitamins for Maximum Benefits, According to a Pharmacist

Table of ContentsView AllTable of ContentsWhen to Take Your VitaminsWater-soluble VitaminsFat-Soluble VitaminsMultivitaminsPrenatal VitaminsTips for Taking Supplements

Table of ContentsView All

View All

Table of Contents

When to Take Your Vitamins

Water-soluble Vitamins

Fat-Soluble Vitamins

Multivitamins

Prenatal Vitamins

Tips for Taking Supplements

The human body needs 13 different vitamins, which ideally should come from a balanced diet. The Dietary Guidelines for Americans emphasizes getting nutrients primarily from food. Still, many people fall short of meeting recommendations for key nutrients and choose daily vitamin supplements to fill the gaps.Vitaminsare available as single-nutrient supplements and in multivitamin products.

Taking vitamins might seem straightforward, but timing can make a big difference in how well your body absorbs them. Some work better in the morning, while others can be taken any time if you pair them with meals. Factors like the type of vitamin, your diet, medications, and even lifestyle choices like smoking can all influence vitamin absorption.

In the United States, the Food and Drug Administration (FDA) does not regulate dietary supplements the way it does for prescription medications. As a result, some supplement products may not contain the ingredients listed on the label.

While not a complete guide, the chart below offers a quick overview of the best time of day to take some common vitamin supplements.

Best time of day to take some common vitamin supplementsVitaminBest Time to Take ThemVitamin CAnytime; on an empty stomach or with meals if sensitive to acidsVitamin B12Morning, but not at the same time as vitamin CVitamin DMorning or with meals containing fatVitamin AWith meals that include some fatVitamin EWith meals that include some fatVitamin KWith meals that include some fatMultivitaminsWith a meal, ideally in the morning or afternoonPrenatal vitaminsAnytime, but with a meal to reduce nauseaIronMorning, with vitamin C or orange juiceKeep in mind that the guide above is just a general overview. Your needs may vary, especially if you have acute or chronic health conditions or take prescription medications. Your pharmacist or healthcare provider can offer personalized guidance on the best timing and supplements to avoid interfering with any other treatments.Water-soluble VitaminsVitamins are divided intotwo main groups: vitamins that dissolve in water (water-soluble) and vitamins that dissolve in fat (fat-soluble). For most people, water-soluble vitamins can be taken at any time of day.Water-soluble vitamins are not stored in your body, so you must replenish them regularly to avoid deficiencies. Excess amounts are flushed out in your urine, but in rare cases, problems still arise if you have too much of certain ones in your body.For example, too much vitamin C at once can cause diarrhea, and an excess of vitamin B6 can lead to nerve damage.B VitaminsB vitamins are a group of eight water-soluble vitamins that support metabolism, red blood cell production, and nerve function, among other essential roles.Vitamin B supplements are available as individual micronutrient supplements as well as B-complex supplements that contain all of the following:Vitamin B1:ThiamineVitamin B2:RiboflavinVitamin B3:NiacinVitamin B5:Pantothenic acidVitamin B6:PyridoxineVitamin B7:BiotinVitamin B9:Folate (folic acid)Vitamin B12:CobalaminVitamin B12 is unique among water-soluble vitamins because it can be stored in the liver for long periods, sometimes years.So, it’s important not to take more than your healthcare provider recommends. Some experts suggest taking B12 in the morning as it is thought to offer anenergy boost. To avoid reducing effectiveness, however, do not take vitamin B12 supplements at the same time as vitamin C.Other B vitamins can be taken at any time of day. Food does not affect absorption, but taking it with a meal may reduce nausea or upset stomach. Choosing a consistent time of day can help you remember it.Vitamin CVitamin C, another water-soluble vitamin, plays a vital role in maintaining healthy cells, repairing tissues, and supporting your immune system.There isn’t necessarily abest time of day for vitamin C, but taking it on an empty stomach with plenty of water can help maximize its absorption. However, if you’re sensitive to its acidity or prone to stomach upset, you can take vitamin C with meals or choose a “buffered” version, which is formulated to be gentler on digestion.Taking a large amount of vitamin C at once can cause diarrhea or indigestion, though, so it may be best to split it into smaller doses throughout the day.Fat-Soluble VitaminsThe four fat-soluble vitamins are A, D, E, and K—all the other types of vitamins are water-soluble vitamins. They are absorbed in the intestines in the presence of dietary fat.These vitamins are best taken withfood that includes some fat, such as nuts, avocado, or olive oil.Fat-soluble vitamins are stored in your body for later use, specifically in your liver, fatty tissues, and muscles. Unlike water-soluble vitamins, they are not washed away in your urine.Most people get enough of these vitamins from food and natural sources without adding supplements. Excessive amounts of fat-soluble vitamin supplements can build up and becometoxic. Check with a healthcare professional regarding dosage and safety limitations.Vitamin AVitamin Ais essential for vision, immune health, and reproduction. Natural sources of vitamin A include liver, fish, egg yolk, and brightly colored fruits and vegetables like carrots and sweet potatoes.If you take a vitamin A supplement, it’s best to take it with a fat-containing meal. Any time of day works.Vitamin DTakingvitamin D in the morningmay be more effective, as some evidence suggests it can interfere with melatonin (a hormone that regulates yourcircadian rhythm) production and affect sleep if taken at night.Vitamin D levels can affect your sleep, with low levels linked to fewer hours of sleep and poor sleep quality.As with other fat-soluble vitamins, pair vitamin D with a meal containing fat to support optimal absorption.Vitamin D also plays a crucial role in aiding calcium absorption, making it a common pairing withcalcium supplements.If your supplement contains calcium and vitamin D, it’s best taken with food.As with other fat-soluble vitamins, it’s a good idea to check with a healthcare provider before adding a vitamin D supplement to your routine. They can test your blood levels to see if you’re deficient. Taking too much vitamin D can be harmful, raising the risk of kidney stones, digestive upset,elevated calcium levels, high blood pressure, and other complications.Vitamin ELike vitamins A and D,vitamin Erequires dietary fat for proper absorption. Taking it with meals rich in healthy fats can enhance its effectiveness.Vitamin KVitamin Kis key for blood clotting and bone health. As with other fat-soluble vitamins, it should be taken with meals that include some fat for better absorption.MultivitaminsMultivitaminscombine water- and fat-soluble vitamins, and many also contain mineral nutrients. There is no optimal time of day to take a multivitamin per se, but it’s best to take it with a meal to aid the absorption of fat-soluble vitamins and prevent an upset stomach.Drinking plenty of water along with your multivitamin also helps promote absorption of the water-soluble ingredients.Taking multivitamins on an empty stomach may cause nausea and vomiting for some people. While not a requirement, taking your multivitamin in the morning or afternoon may be better than in the evening. Digestion slows overnight, which may affect nutrient absorption.As mentioned, many multivitamin products also contain minerals, such as calcium andmagnesium. Minerals can bind to certain medications, like some antibiotics, and reduce their absorption. To prevent interactions, it’s best to take them a few hours apart. Consult your provider or pharmacist for guidance.Prenatal VitaminsPrenatal vitaminsare vital for supporting fetal development and meeting your body’s increased demands during pregnancy. These supplements contain essential nutrients for pregnancy, including folic acid, iron, calcium, vitamin D,choline, B vitamins, and vitamin C. Many prenatal vitamins also containomega-3 fatty acids.While you can take a prenatal vitamin at any time of day, pairing it with food helps reducenausea. Be sure to check the serving size on your product label. Some prenatal vitamins require more than one pill per day.Folic acid, a type of B vitamin, is especially important during early pregnancy to support neural tube development. For most people, 400 micrograms daily (at any time of day) is enough to help reduce the risk of neural tube defects.Consult your healthcare provider to ensure your prenatal vitamin meets your specific needs or if an additional folic acid supplement may be needed.Tips for Taking SupplementsOverall, when it comes to vitamin supplements, there are a few guidelines to follow:Stick to the recommended dosage on the product label unless your healthcare provider advises otherwise.Take fat-soluble vitamins (vitamins A, D, E, or K) with meals containing fat.Take multivitamin supplements with food.Water-soluble vitamins, such as vitamin C, may be taken on an empty stomach. If this upsets your stomach, taking it with a small amount of food is generally OK, too.Avoid alcohol and smoking when taking your vitamins, as these can affect vitamin absorption.It’s best to takeiron supplementsin the morning with orange juice or a vitamin C supplement before having any food or coffee.Vitamin supplements that contain minerals, like calcium or magnesium, could interact with medications. Ask your pharmacist how to space them appropriately.In most cases, it’s safe to take several different vitamins at the same time of day. But if you also take medications or cancer treatments, check with a healthcare provider or pharmacist first to help create a routine that supports your health needs.SummaryTiming your vitamins can help you get the most out of them. Water-soluble vitamins like C and B12 are best taken in the morning, while fat-soluble vitamins like A, D, E, and K should be taken with meals containing fat. Multivitamins and prenatal vitamins benefit from pairing with food to maximize absorption and reduce side effects like nausea.Keep in mind that vitamin supplements are regulated as food, not drugs, so they are not evaluated for safety or efficacy in the same way medications are.Always check with your healthcare provider before starting a new vitamin supplement to confirm it’s safe for you.

Keep in mind that the guide above is just a general overview. Your needs may vary, especially if you have acute or chronic health conditions or take prescription medications. Your pharmacist or healthcare provider can offer personalized guidance on the best timing and supplements to avoid interfering with any other treatments.

Vitamins are divided intotwo main groups: vitamins that dissolve in water (water-soluble) and vitamins that dissolve in fat (fat-soluble). For most people, water-soluble vitamins can be taken at any time of day.

Water-soluble vitamins are not stored in your body, so you must replenish them regularly to avoid deficiencies. Excess amounts are flushed out in your urine, but in rare cases, problems still arise if you have too much of certain ones in your body.For example, too much vitamin C at once can cause diarrhea, and an excess of vitamin B6 can lead to nerve damage.

B Vitamins

B vitamins are a group of eight water-soluble vitamins that support metabolism, red blood cell production, and nerve function, among other essential roles.

Vitamin B supplements are available as individual micronutrient supplements as well as B-complex supplements that contain all of the following:

Vitamin B12 is unique among water-soluble vitamins because it can be stored in the liver for long periods, sometimes years.So, it’s important not to take more than your healthcare provider recommends. Some experts suggest taking B12 in the morning as it is thought to offer anenergy boost. To avoid reducing effectiveness, however, do not take vitamin B12 supplements at the same time as vitamin C.

Other B vitamins can be taken at any time of day. Food does not affect absorption, but taking it with a meal may reduce nausea or upset stomach. Choosing a consistent time of day can help you remember it.

Vitamin C

Vitamin C, another water-soluble vitamin, plays a vital role in maintaining healthy cells, repairing tissues, and supporting your immune system.

There isn’t necessarily abest time of day for vitamin C, but taking it on an empty stomach with plenty of water can help maximize its absorption. However, if you’re sensitive to its acidity or prone to stomach upset, you can take vitamin C with meals or choose a “buffered” version, which is formulated to be gentler on digestion.

Taking a large amount of vitamin C at once can cause diarrhea or indigestion, though, so it may be best to split it into smaller doses throughout the day.

The four fat-soluble vitamins are A, D, E, and K—all the other types of vitamins are water-soluble vitamins. They are absorbed in the intestines in the presence of dietary fat.These vitamins are best taken withfood that includes some fat, such as nuts, avocado, or olive oil.

Fat-soluble vitamins are stored in your body for later use, specifically in your liver, fatty tissues, and muscles. Unlike water-soluble vitamins, they are not washed away in your urine.

Most people get enough of these vitamins from food and natural sources without adding supplements. Excessive amounts of fat-soluble vitamin supplements can build up and becometoxic. Check with a healthcare professional regarding dosage and safety limitations.

Vitamin A

Vitamin Ais essential for vision, immune health, and reproduction. Natural sources of vitamin A include liver, fish, egg yolk, and brightly colored fruits and vegetables like carrots and sweet potatoes.

If you take a vitamin A supplement, it’s best to take it with a fat-containing meal. Any time of day works.

Vitamin D

Takingvitamin D in the morningmay be more effective, as some evidence suggests it can interfere with melatonin (a hormone that regulates yourcircadian rhythm) production and affect sleep if taken at night.Vitamin D levels can affect your sleep, with low levels linked to fewer hours of sleep and poor sleep quality.

As with other fat-soluble vitamins, pair vitamin D with a meal containing fat to support optimal absorption.

Vitamin D also plays a crucial role in aiding calcium absorption, making it a common pairing withcalcium supplements.If your supplement contains calcium and vitamin D, it’s best taken with food.

As with other fat-soluble vitamins, it’s a good idea to check with a healthcare provider before adding a vitamin D supplement to your routine. They can test your blood levels to see if you’re deficient. Taking too much vitamin D can be harmful, raising the risk of kidney stones, digestive upset,elevated calcium levels, high blood pressure, and other complications.

Vitamin E

Like vitamins A and D,vitamin Erequires dietary fat for proper absorption. Taking it with meals rich in healthy fats can enhance its effectiveness.

Vitamin K

Vitamin Kis key for blood clotting and bone health. As with other fat-soluble vitamins, it should be taken with meals that include some fat for better absorption.

Multivitaminscombine water- and fat-soluble vitamins, and many also contain mineral nutrients. There is no optimal time of day to take a multivitamin per se, but it’s best to take it with a meal to aid the absorption of fat-soluble vitamins and prevent an upset stomach.Drinking plenty of water along with your multivitamin also helps promote absorption of the water-soluble ingredients.

Taking multivitamins on an empty stomach may cause nausea and vomiting for some people. While not a requirement, taking your multivitamin in the morning or afternoon may be better than in the evening. Digestion slows overnight, which may affect nutrient absorption.

As mentioned, many multivitamin products also contain minerals, such as calcium andmagnesium. Minerals can bind to certain medications, like some antibiotics, and reduce their absorption. To prevent interactions, it’s best to take them a few hours apart. Consult your provider or pharmacist for guidance.

Prenatal vitaminsare vital for supporting fetal development and meeting your body’s increased demands during pregnancy. These supplements contain essential nutrients for pregnancy, including folic acid, iron, calcium, vitamin D,choline, B vitamins, and vitamin C. Many prenatal vitamins also containomega-3 fatty acids.

While you can take a prenatal vitamin at any time of day, pairing it with food helps reducenausea. Be sure to check the serving size on your product label. Some prenatal vitamins require more than one pill per day.

Folic acid, a type of B vitamin, is especially important during early pregnancy to support neural tube development. For most people, 400 micrograms daily (at any time of day) is enough to help reduce the risk of neural tube defects.Consult your healthcare provider to ensure your prenatal vitamin meets your specific needs or if an additional folic acid supplement may be needed.

Overall, when it comes to vitamin supplements, there are a few guidelines to follow:

Summary

Timing your vitamins can help you get the most out of them. Water-soluble vitamins like C and B12 are best taken in the morning, while fat-soluble vitamins like A, D, E, and K should be taken with meals containing fat. Multivitamins and prenatal vitamins benefit from pairing with food to maximize absorption and reduce side effects like nausea.

Keep in mind that vitamin supplements are regulated as food, not drugs, so they are not evaluated for safety or efficacy in the same way medications are.Always check with your healthcare provider before starting a new vitamin supplement to confirm it’s safe for you.

19 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Marra MV, Bailey RL.Position of the Academy of Nutrition and Dietetics: Micronutrient supplementation.J Acad Nutr Diet. 2018;118(11):2162-2173. doi:10.1016/j.jand.2018.07.022NIH Office of Dietary Supplements.Background information: dietary supplements.MedlinePlus.Vitamins.NIH Office of Dietary Supplements.Vitamin B6 fact sheet for consumers.NIH Office of Dietary Supplements.Vitamin C fact sheet for consumers.Calderón-Ospina CA, Nava-Mesa MO.B vitamins in the nervous system: current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin.CNS Neurosci Ther. 2020;26(1):5-13. doi:10.1111/cns.13207MedlinePlus.Vitamin B12.Yamada K, Shimodaira M, Chida S, et al.Degradation of vitamin B12 in dietary supplements.Int J Vitam Nutr Res. 2008;78(4-5):195-203. doi:10.1024/0300-9831.78.45.195Carr AC, Vissers MC.Synthetic or food-derived vitamin C–are they equally bioavailable?.Nutrients. 2013;5(11):4284-4304. doi:10.3390/nu5114284Youness RA, Dawoud A, ElTahtawy O, Farag MA.Fat-soluble vitamins: updated review of their role and orchestration in human nutrition throughout life cycle with sex differences.Nutr Metab (Lond). 2022;19(1):60. doi:10.1186/s12986-022-00696-yGhareghani M, Zibara K, Rivest S.Melatonin and vitamin D, two sides of the same coin, better to land on its edge to improve multiple sclerosis.Proc Natl Acad Sci U S A. 2023;120(14):e2219334120. doi:10.1073/pnas.2219334120Abboud M.Vitamin D supplementation and sleep: a systematic review and meta-analysis of intervention studies.Nutrients. 2022;14(5):1076. doi:10.3390/nu14051076Fleet JC.Vitamin D-mediated Regulation of intestinal calcium absorption.Nutrients. 2022;14(16):3351. doi:10.3390/nu14163351NIH Office of Dietary Supplements.Multivitamin/mineral supplement fact sheet for health professionals.American College of Obstetricians and Gynecologists.Nutrition during pregnancy.NIH Office of Dietary Supplements.Folate fact sheet for consumers.Butts M, Sundaram VL, Murughiyan U, et al.The influence of alcohol consumption on intestinal nutrient absorption: a comprehensive review.Nutrients. 2023;15(7):1571. doi:10.3390/nu15071571Yang L, Zhao H, Liu K, et al.Smoking behavior and circulating vitamin D levels in adults: a meta-analysis.Food Sci Nutr. 2021;9(10):5820-5832. doi:10.1002/fsn3.2488von Siebenthal HK, Moretti D, Zimmermann MB, Stoffel NU.Effect of dietary factors and time of day on iron absorption from oral iron supplements in iron deficient women.Am J Hematol. 2023;98(9):1356-1363. doi:10.1002/ajh.26987

19 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Marra MV, Bailey RL.Position of the Academy of Nutrition and Dietetics: Micronutrient supplementation.J Acad Nutr Diet. 2018;118(11):2162-2173. doi:10.1016/j.jand.2018.07.022NIH Office of Dietary Supplements.Background information: dietary supplements.MedlinePlus.Vitamins.NIH Office of Dietary Supplements.Vitamin B6 fact sheet for consumers.NIH Office of Dietary Supplements.Vitamin C fact sheet for consumers.Calderón-Ospina CA, Nava-Mesa MO.B vitamins in the nervous system: current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin.CNS Neurosci Ther. 2020;26(1):5-13. doi:10.1111/cns.13207MedlinePlus.Vitamin B12.Yamada K, Shimodaira M, Chida S, et al.Degradation of vitamin B12 in dietary supplements.Int J Vitam Nutr Res. 2008;78(4-5):195-203. doi:10.1024/0300-9831.78.45.195Carr AC, Vissers MC.Synthetic or food-derived vitamin C–are they equally bioavailable?.Nutrients. 2013;5(11):4284-4304. doi:10.3390/nu5114284Youness RA, Dawoud A, ElTahtawy O, Farag MA.Fat-soluble vitamins: updated review of their role and orchestration in human nutrition throughout life cycle with sex differences.Nutr Metab (Lond). 2022;19(1):60. doi:10.1186/s12986-022-00696-yGhareghani M, Zibara K, Rivest S.Melatonin and vitamin D, two sides of the same coin, better to land on its edge to improve multiple sclerosis.Proc Natl Acad Sci U S A. 2023;120(14):e2219334120. doi:10.1073/pnas.2219334120Abboud M.Vitamin D supplementation and sleep: a systematic review and meta-analysis of intervention studies.Nutrients. 2022;14(5):1076. doi:10.3390/nu14051076Fleet JC.Vitamin D-mediated Regulation of intestinal calcium absorption.Nutrients. 2022;14(16):3351. doi:10.3390/nu14163351NIH Office of Dietary Supplements.Multivitamin/mineral supplement fact sheet for health professionals.American College of Obstetricians and Gynecologists.Nutrition during pregnancy.NIH Office of Dietary Supplements.Folate fact sheet for consumers.Butts M, Sundaram VL, Murughiyan U, et al.The influence of alcohol consumption on intestinal nutrient absorption: a comprehensive review.Nutrients. 2023;15(7):1571. doi:10.3390/nu15071571Yang L, Zhao H, Liu K, et al.Smoking behavior and circulating vitamin D levels in adults: a meta-analysis.Food Sci Nutr. 2021;9(10):5820-5832. doi:10.1002/fsn3.2488von Siebenthal HK, Moretti D, Zimmermann MB, Stoffel NU.Effect of dietary factors and time of day on iron absorption from oral iron supplements in iron deficient women.Am J Hematol. 2023;98(9):1356-1363. doi:10.1002/ajh.26987

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Marra MV, Bailey RL.Position of the Academy of Nutrition and Dietetics: Micronutrient supplementation.J Acad Nutr Diet. 2018;118(11):2162-2173. doi:10.1016/j.jand.2018.07.022NIH Office of Dietary Supplements.Background information: dietary supplements.MedlinePlus.Vitamins.NIH Office of Dietary Supplements.Vitamin B6 fact sheet for consumers.NIH Office of Dietary Supplements.Vitamin C fact sheet for consumers.Calderón-Ospina CA, Nava-Mesa MO.B vitamins in the nervous system: current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin.CNS Neurosci Ther. 2020;26(1):5-13. doi:10.1111/cns.13207MedlinePlus.Vitamin B12.Yamada K, Shimodaira M, Chida S, et al.Degradation of vitamin B12 in dietary supplements.Int J Vitam Nutr Res. 2008;78(4-5):195-203. doi:10.1024/0300-9831.78.45.195Carr AC, Vissers MC.Synthetic or food-derived vitamin C–are they equally bioavailable?.Nutrients. 2013;5(11):4284-4304. doi:10.3390/nu5114284Youness RA, Dawoud A, ElTahtawy O, Farag MA.Fat-soluble vitamins: updated review of their role and orchestration in human nutrition throughout life cycle with sex differences.Nutr Metab (Lond). 2022;19(1):60. doi:10.1186/s12986-022-00696-yGhareghani M, Zibara K, Rivest S.Melatonin and vitamin D, two sides of the same coin, better to land on its edge to improve multiple sclerosis.Proc Natl Acad Sci U S A. 2023;120(14):e2219334120. doi:10.1073/pnas.2219334120Abboud M.Vitamin D supplementation and sleep: a systematic review and meta-analysis of intervention studies.Nutrients. 2022;14(5):1076. doi:10.3390/nu14051076Fleet JC.Vitamin D-mediated Regulation of intestinal calcium absorption.Nutrients. 2022;14(16):3351. doi:10.3390/nu14163351NIH Office of Dietary Supplements.Multivitamin/mineral supplement fact sheet for health professionals.American College of Obstetricians and Gynecologists.Nutrition during pregnancy.NIH Office of Dietary Supplements.Folate fact sheet for consumers.Butts M, Sundaram VL, Murughiyan U, et al.The influence of alcohol consumption on intestinal nutrient absorption: a comprehensive review.Nutrients. 2023;15(7):1571. doi:10.3390/nu15071571Yang L, Zhao H, Liu K, et al.Smoking behavior and circulating vitamin D levels in adults: a meta-analysis.Food Sci Nutr. 2021;9(10):5820-5832. doi:10.1002/fsn3.2488von Siebenthal HK, Moretti D, Zimmermann MB, Stoffel NU.Effect of dietary factors and time of day on iron absorption from oral iron supplements in iron deficient women.Am J Hematol. 2023;98(9):1356-1363. doi:10.1002/ajh.26987

Marra MV, Bailey RL.Position of the Academy of Nutrition and Dietetics: Micronutrient supplementation.J Acad Nutr Diet. 2018;118(11):2162-2173. doi:10.1016/j.jand.2018.07.022

NIH Office of Dietary Supplements.Background information: dietary supplements.

MedlinePlus.Vitamins.

NIH Office of Dietary Supplements.Vitamin B6 fact sheet for consumers.

NIH Office of Dietary Supplements.Vitamin C fact sheet for consumers.

Calderón-Ospina CA, Nava-Mesa MO.B vitamins in the nervous system: current knowledge of the biochemical modes of action and synergies of thiamine, pyridoxine, and cobalamin.CNS Neurosci Ther. 2020;26(1):5-13. doi:10.1111/cns.13207

MedlinePlus.Vitamin B12.

Yamada K, Shimodaira M, Chida S, et al.Degradation of vitamin B12 in dietary supplements.Int J Vitam Nutr Res. 2008;78(4-5):195-203. doi:10.1024/0300-9831.78.45.195

Carr AC, Vissers MC.Synthetic or food-derived vitamin C–are they equally bioavailable?.Nutrients. 2013;5(11):4284-4304. doi:10.3390/nu5114284

Youness RA, Dawoud A, ElTahtawy O, Farag MA.Fat-soluble vitamins: updated review of their role and orchestration in human nutrition throughout life cycle with sex differences.Nutr Metab (Lond). 2022;19(1):60. doi:10.1186/s12986-022-00696-y

Ghareghani M, Zibara K, Rivest S.Melatonin and vitamin D, two sides of the same coin, better to land on its edge to improve multiple sclerosis.Proc Natl Acad Sci U S A. 2023;120(14):e2219334120. doi:10.1073/pnas.2219334120

Abboud M.Vitamin D supplementation and sleep: a systematic review and meta-analysis of intervention studies.Nutrients. 2022;14(5):1076. doi:10.3390/nu14051076

Fleet JC.Vitamin D-mediated Regulation of intestinal calcium absorption.Nutrients. 2022;14(16):3351. doi:10.3390/nu14163351

NIH Office of Dietary Supplements.Multivitamin/mineral supplement fact sheet for health professionals.

American College of Obstetricians and Gynecologists.Nutrition during pregnancy.

NIH Office of Dietary Supplements.Folate fact sheet for consumers.

Butts M, Sundaram VL, Murughiyan U, et al.The influence of alcohol consumption on intestinal nutrient absorption: a comprehensive review.Nutrients. 2023;15(7):1571. doi:10.3390/nu15071571

Yang L, Zhao H, Liu K, et al.Smoking behavior and circulating vitamin D levels in adults: a meta-analysis.Food Sci Nutr. 2021;9(10):5820-5832. doi:10.1002/fsn3.2488

von Siebenthal HK, Moretti D, Zimmermann MB, Stoffel NU.Effect of dietary factors and time of day on iron absorption from oral iron supplements in iron deficient women.Am J Hematol. 2023;98(9):1356-1363. doi:10.1002/ajh.26987

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