Drug-induced nutrient depletion

Cholestyramine & Nutrient Depletion

Also searched as Questran. What the clinical evidence reports, what it may mean, and what to discuss with your pharmacist.

Medical content reviewed by Dr. Brian Staiger, PharmD, BCPS · Last reviewed July 2026
12Nutrient associations
Insignificant DepletionHighest rating
The bottom line

Cholestyramine has been associated with depletion of BETA-CAROTENE, CALCIUM, IRON and MAGNESIUM and 8 more. This does not mean a deficiency will occur — it means these are worth knowing about and, if you take Cholestyramine long-term, worth raising with your pharmacist or healthcare provider.

Ask a pharmacist about Cholestyramine Free · usually answered within 24 hours

Take more than one medication? Open the checker with Cholestyramine pre-loaded and add the rest to see overlapping nutrient signals.

The evidence

Reported nutrient depletions with Cholestyramine

Each record below is shown as published in our licensed clinical database, with its evidence rating and citations. Expand a section for food sources and talking points.

BETA-CAROTENE

Insignificant Depletion

BILE ACID SEQUESTRANTS

Bile acid sequestrants may modestly reduce absorption of beta-carotene.

Cholestyramine (Questran) and colestipol (Colestid) can reduce absorption of fat-soluble vitamins, including beta-carotene. Serum levels of beta-carotene can be reduced, but this is probably only in proportion to the lowering of cholesterol (on which beta-carotene is transported). Supplements are not usually needed.
Taking Cholestyramine? A supplement is not needed for most patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Beta-carotene is a plant pigment your body converts into vitamin A, which supports healthy vision, skin, and immune function. Cholestyramine works in your gut by binding to bile acids, and because beta-carotene is a fat-soluble nutrient, some of it may get caught up in that process and absorbed a little less efficiently. Here is the reassuring part: any dip in blood levels appears to be tied to the expected drop in cholesterol (which normally carries beta-carotene through the bloodstream), not a true shortage of the nutrient itself. For most people on cholestyramine, a supplement is not needed, but feel free to mention it to your pharmacist or doctor if you have concerns.

What Vitamin A does & food sources

Vitamin A supports vision, immune function, and skin health.

Common food sources:

  • Liver and fish oils
  • Dairy and eggs
  • Orange and yellow vegetables (as beta-carotene)
  • Leafy greens

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

Ask your provider before supplementing vitamin A — status testing is not routine, and intake from food plus multivitamins is often already adequate.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

Vitamin A is fat-soluble and accumulates; excess is harmful (and dangerous in pregnancy). Prefer food sources unless a clinician advises otherwise.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: Avoid high-dose vitamin A in pregnancy or when trying to conceive unless a clinician directs it.

Learn more about this nutrient: Beta-carotene — uses, safety & interactions

References (5)
  1. Hathcock JN. Metabolic mechanisms of drug-nutrient interactions. Fed Proc 1985;44:124-9.
  2. Elinder LS, Hadell K, Johansson J, et al. Probucol treatment decreases serum concentrations of diet-derived antioxidants. Arterioscler Thromb Vasc Biol 1995;15:1057-63. PubMed
  3. Knodel LC, Talbert RL. Adverse effects of hypolipidaemic drugs. Med Toxicol 1987;2:10-32. PubMed
  4. Tonstad S, Silverstein M, Aksnes L, Ose L. Low dose colestipol in adolescents with familial hypercholesterolemia. Arch Dis Child 1996;74:157-60.
  5. Matsui MS, Rozovski SJ. Drug-nutrient interaction. Clin Ther 1982;4:423-40.

CALCIUM

Insignificant Depletion

CHOLESTYRAMINE (Questran)

Taking cholestyramine might decrease calcium absorption, but this is unlikely to increase calcium requirements for most people.

Cholestyramine can reduce absorption of vitamin D, which in turn reduces absorption of calcium. Occasionally this can lead to osteomalacia, usually in patients receiving large doses of cholestyramine (more than 32 grams per day), or prolonged therapy (more than two years). It can also occur in the presence of additional risk factors such as ileal resection or primary biliary cirrhosis. However, cholestyramine (24 grams/day) for treatment of hyperlipidemia in otherwise healthy men doesn't seem to affect vitamin D or calcium levels.
Taking Cholestyramine? A supplement is not needed for most patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Calcium keeps your bones strong and helps your muscles and heart work properly, so it is worth understanding how cholestyramine fits in. This medication works in your gut by binding to bile acids, but it can also catch fat-soluble vitamins like vitamin D along the way, and since your body needs vitamin D to pull calcium in from food, less vitamin D can mean slightly less calcium absorbed. For most people at normal doses, studies suggest this does not meaningfully change calcium levels, and no supplement is needed. If you have been on a high dose for a long time or have other gut or liver conditions, it is worth mentioning to your pharmacist or doctor just to be sure.

What Calcium does & food sources

Calcium builds and maintains bone and is essential for muscle contraction and nerve signaling.

Common food sources:

  • Dairy products (milk, yogurt, cheese)
  • Fortified plant milks and juices
  • Canned fish with bones (sardines, salmon)
  • Leafy greens like kale

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

Ask your provider whether bone health monitoring (and vitamin D testing) makes sense with long-term use of an associated medication — a blood calcium level alone does not capture bone calcium status.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

Calcium can interfere with the absorption of several medications (some antibiotics, thyroid medication, iron) — separate the doses and confirm timing with your pharmacist. Total intake from food plus supplements matters more than supplements alone.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: Very high calcium intake has its own risks (kidney stones in susceptible people) — more is not better.

Learn more about this nutrient: Calcium — uses, safety & interactions

References (5)
  1. Knodel LC, Talbert RL. Adverse effects of hypolipidaemic drugs. Med Toxicol 1987;2:10-32. PubMed
  2. Compston JE, Horton LW. Oral 25-hydroxyvitamin D3 in treatment of osteomalacia associated with ileal resection and cholestyramine therapy. Gastroenterology 1978;74:900-2. DOI
  3. Compston JE, Thompson RP. Intestinal absorption of 25-hydroxyvitamin D and osteomalacia in primary biliary cirrhosis. Lancet 1977;1:721-4. PubMed
  4. Heaton KW, Lever JV, Barnard RE. Osteomalacia associated with cholestyramine therapy for post-ileectomy diarrhea. Gastroenterology 1972;62:642-6.
  5. Hoogwerf BJ, Hibbard DM, Hunninghake DB. Effects of long-term cholestyramine administration on vitamin D and parathormone levels in middle-aged men with hypercholesterolaemia. J Lab Clin Med 1992;119:407-11.

IRON

Insignificant Depletion

CHOLESTYRAMINE (Questran)

Cholestyramine might modestly reduce iron absorption and reduce iron levels.

Cholestyramine and colestipol may bind iron in the gut, reducing its absorption. Clinically significant iron deficiency induced by these drugs hasn't been reported, and supplements aren't likely to be needed. If patients are taking iron supplements for other causes of deficiency, recommend they separate the iron and cholestyramine or colestipol doses by at least four hours.
Taking Cholestyramine? A supplement is not needed for most patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Iron is something your body needs to carry oxygen in your blood and keep your energy up. Cholestyramine works by grabbing onto substances in your gut, and it can latch onto iron the same way, leaving a little less of it available for absorption. That said, this is rated as insignificant, meaning actual iron deficiency from cholestyramine has not been reported in practice and most people taking it have nothing to worry about. If you happen to take iron supplements for a separate reason, just let your pharmacist know so they can help you time the two doses at least four hours apart.

What Iron does & food sources

Iron is the core of hemoglobin, which carries oxygen in red blood cells.

Common food sources:

  • Red meat and poultry
  • Beans and lentils
  • Fortified cereals
  • Spinach (plant iron absorbs better with vitamin C)

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

Iron status is easy to assess (ferritin, iron studies, blood counts). Ask your provider before supplementing — unexplained low iron always deserves a medical evaluation for the cause, not just replacement.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

Iron supplements commonly cause constipation or stomach upset and interfere with the absorption of several medications (thyroid medication, some antibiotics). Do not take iron "just in case" — excess iron is harmful.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: Never self-treat suspected anemia; the underlying cause matters as much as the iron level.

Learn more about this nutrient: Iron — uses, safety & interactions

References (1)
  1. Watkins DW, Khalafi R, Cassidy MM, Vahouny GV. Alterations in calcium, magnesium, iron, and zinc metabolism by dietary cholestyramine. Dig Dis Sci 1985;30:477-82.. PubMed

MAGNESIUM

Insignificant Depletion

CHOLESTYRAMINE (Questran)

Small clinical studies show that cholestyramine may slightly increase urinary magnesium excretion, possibly by binding vitamin D and leading to reduced magnesium absorption. Clinically significant magnesium deficiency hasn't been reported, and supplements aren't likely to be needed. For information on foods that are rich in magnesium, see our chart.
Taking Cholestyramine? A supplement is not needed for most patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Magnesium is a mineral your muscles, nerves, and heart rhythm all depend on. Cholestyramine works by binding things in your gut, and there is some evidence it may indirectly reduce magnesium absorption by also soaking up vitamin D, which the body uses to absorb magnesium properly. A small amount of extra magnesium may then spill into the urine as well. That said, small studies rate this as insignificant, meaning real deficiency has not been reported with this drug, and most people taking cholestyramine do not need a magnesium supplement. If you have any concerns, a quick chat with your pharmacist or doctor is all you need.

What Magnesium does & food sources

Magnesium is involved in muscle and nerve function, heart rhythm, blood sugar control, and bone health.

Common food sources:

  • Nuts and seeds (almonds, pumpkin seeds)
  • Whole grains
  • Leafy green vegetables
  • Beans and legumes

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

Ask whether a magnesium level is worth checking if you take an associated medication long-term — particularly with symptoms like muscle cramps, twitching, or palpitations. Blood levels do not always reflect total body stores, which is worth discussing too.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

Magnesium supplements come in many forms and can cause loose stools at higher doses. They can also bind some medications in the gut (certain antibiotics, thyroid medication), so timing matters — check with your pharmacist.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: Magnesium supplementation can be risky in kidney disease, where magnesium can accumulate — always check with a clinician first if your kidney function is reduced.

Learn more about this nutrient: Magnesium — uses, safety & interactions

References (2)
  1. Watkins DW, Khalafi R, Cassidy MM, Vahouny GV. Alterations in calcium, magnesium, iron, and zinc metabolism by dietary cholestyramine. Dig Dis Sci 1985;30:477-82.. PubMed
  2. Runeberg L, Miettinen TA, Nikkila EA. Effect of cholestyramine on mineral excretion in man. Acta Med Scand 1972;192:71-6. PubMed

PHOSPHATE SALTS

Insignificant Depletion

CHOLESTYRAMINE (Questran)

Theoretically, taking cholestyramine might increase the risk of hypophosphatemia and associated adverse effects; cholestyramine and phosphate intake should be separated by at least 2 hours.
Cholestyramine can bind phosphate in the gut. It also reduces absorption of vitamin D which normally acts to increase gastrointestinal absorption and kidney reabsorption of phosphate. There are reports of reduced serum phosphate levels, and occasional hypophosphatemia, in people taking large doses of cholestyramine for more than a year. Cholestyramine doses of 0.2-1.1 grams/kg daily in children and 12-16 grams daily in adults have been associated with reduced phosphate levels. However, most people taking cholestyramine are unlikely to need phosphate supplements unless their dietary intake is low.
Taking Cholestyramine? A supplement is not needed for most patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Phosphate is a mineral your bones, muscles, and cells depend on for energy and structure. Cholestyramine works by binding to things in your gut, and it can grab onto phosphate before your body gets a chance to absorb it. It also reduces how well you absorb vitamin D, which normally helps your body hold onto phosphate. That said, this is rated as insignificant for most people, so unless you are taking very high doses for a long time or your diet is already low in phosphate, this is generally not something to worry about. If you have questions about your specific situation, your pharmacist or doctor is a great place to start.

Learn more about this nutrient: Phosphate Salts — uses, safety & interactions

References (2)
  1. West RJ, Lloyd JK. The effect of cholestyramine on intestinal absorption. Gut 1975;16:93-8. PubMed
  2. Heaton KW, Lever JV, Barnard RE. Osteomalacia associated with cholestyramine therapy for post-ileectomy diarrhea. Gastroenterology 1972;62:642-6.

VITAMIN B12

Insignificant Depletion

BILE ACID SEQUESTRANTS

Bile acid sequestrants might reduce vitamin B12 absorption, but this is unlikely to be clinically significant.

These resins can decrease gastrointestinal (GI) absorption of vitamin B12 by binding intrinsic factor and vitamin B12-intrinsic factor complexes. However, absorption isn't completely prevented. It's unlikely that this interaction will deplete body stores of vitamin B12 unless there are other factors contributing to deficiency. In a group of children treated with cholestyramine for up to 2.5 years, there was no change in serum vitamin B12 levels. Routine supplements aren't necessary.
Taking Cholestyramine? A supplement is not needed for most patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Vitamin B12 is something your nerves and red blood cells genuinely depend on, so it is worth knowing how cholestyramine fits in. This medication works in the gut by grabbing onto bile acids, but it can also latch onto a protein called intrinsic factor that normally escorts B12 into your bloodstream. That said, the binding is not complete, and a study in children who took cholestyramine for over two years showed no drop in B12 levels at all. For most people on this medication, this is not something to worry about, though if you have other reasons to be concerned about your B12, it is worth a quick conversation with your pharmacist or doctor.

What Vitamin B12 does & food sources

Vitamin B12 supports red blood cell formation, nerve function, and DNA synthesis.

Common food sources:

  • Meat, poultry, and fish
  • Eggs and dairy products
  • Fortified cereals and nutritional yeast

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

If you take an associated medication long-term, ask your healthcare provider whether checking a vitamin B12 level (sometimes with methylmalonic acid) is appropriate — especially if you notice fatigue, numbness, tingling, or memory changes.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

B12 status is easy to check and low levels are usually straightforward to address, so testing before supplementing is often the sensible order. High-dose folic acid can mask a B12 deficiency, which is one reason B12 and folate questions are best sorted out together with your provider.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: B12 deficiency can look like other conditions — do not self-diagnose from symptoms alone.

Learn more about this nutrient: Vitamin B12 — uses, safety & interactions

References (3)
  1. Coronato A, Glass GB. Depression of the intestinal uptake of radio-vitamin B12 by cholestyramine. Proc Soc Exp Biol Med 1973;142:1341-4. DOI
  2. Leonard JP, Desager JP, Beckers C, Harvengt C. In vitro binding of various biological substances by two hypocholesterolemic resins. Arzneimittelforschung 1979;29:97-81.
  3. West RJ, Lloyd JK. The effect of cholestyramine on intestinal absorption. Gut 1975;16:93-8. PubMed

VITAMIN E

Insignificant Depletion

BILE ACID SEQUESTRANTS

Bile acid sequestrants might reduce vitamin E levels.

Cholestyramine (Questran) and colestipol (Colestid) reduce absorption of dietary fat, so there is concern that they might reduce absorption of fat soluble vitamins, including vitamin E. Some studies suggest that the bile acid sequestrants lower vitamin E levels by 7% to 20%. But other studies have found no effect on vitamin E levels. When decreases did occur, they were often in proportion to the lowering of LDL (on which vitamin E is transported), and did not fall below the lower limit of normal (5 micrograms/mL) with up to 2 years of treatment. Routine vitamin E supplements aren't necessary, but consider them for patients who take high doses of bile acid sequestrants for several years, or who have low serum vitamin E levels.
Taking Cholestyramine? A supplement is not needed for most patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Vitamin E is a fat-soluble nutrient your body uses as an antioxidant to protect cells from damage. Because cholestyramine works in the gut by binding bile acids and reducing fat absorption, there has been some concern that fat-soluble vitamins like vitamin E could get swept along and absorbed less efficiently. Research on this is actually mixed, though, and any dip seen in vitamin E levels was small and stayed within the normal range even after two years of use. For most people on this medication, this is not something to worry about, but if you have been on a high dose for several years, it is worth a quick conversation with your pharmacist or doctor.

What Vitamin E does & food sources

Vitamin E is a fat-soluble antioxidant that protects cell membranes.

Common food sources:

  • Vegetable oils
  • Nuts and seeds
  • Wheat germ
  • Leafy greens

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

Deficiency is rare; ask your provider before supplementing, particularly if you take blood thinners.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

Higher-dose vitamin E can increase bleeding tendency, especially with warfarin or antiplatelet medications.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: Discuss vitamin E supplements with your provider if you take any blood thinner.

Learn more about this nutrient: Vitamin E — uses, safety & interactions

References (7)
  1. West RJ, Lloyd JK. The effect of cholestyramine on intestinal absorption. Gut 1975;16:93-8. PubMed
  2. Cywes C, Millar AJ. Assessment of the nutritional status of infants and children with biliary atresia. S Afr Med J 1990;77:131-5.
  3. Elinder LS, Hadell K, Johansson J, et al. Probucol treatment decreases serum concentrations of diet-derived antioxidants. Arterioscler Thromb Vasc Biol 1995;15:1057-63. PubMed
  4. Schwarz KB, Goldstein PD, Witztum JL, et al. Fat-soluble vitamin concentrations in hypercholestrolemic children treated with colestipol. Pediatrics 1980;65:243-50.
  5. Tonstad S, Silverstein M, Aksnes L, Ose L. Low dose colestipol in adolescents with familial hypercholesterolemia. Arch Dis Child 1996;74:157-60.
  6. Schade RWB, van't Laar A, Majoor CLH, Jansen AP. A comparative study of the effects of cholestyramine and neomycin in the treatment of type II hyperlipoproteinemia. Acta Med Scand 1976;199:175-80..
  7. Glueck CJ, Tsang RC, Fallat RW, Scheel D. Plasma vitamin A and E levels in children with familial type II hyperlipoproteinemia during therapy with diet and cholestyramine resin. Pediatrics 1974;54:51-5.. DOI

ZINC

Insignificant Depletion

CHOLESTYRAMINE (Questran)

Cholestyramine might modestly reduce zinc absorption and zinc levels.

Limited animal research suggests cholestyramine might reduce zinc absorption; however, this is not likely to be clinically significant.
Taking Cholestyramine? A supplement is not needed for most patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Zinc is a mineral your immune system, wound healing, and sense of taste all depend on. Cholestyramine works by binding substances in the gut to carry them out of the body, and there is some thought it could lightly interfere with zinc absorption the same way. That said, this comes mostly from animal studies, and the effect is considered insignificant for most people taking the medication. No action is needed for the average patient, but if you have concerns about your zinc levels, a quick conversation with your pharmacist or doctor can put your mind at ease.

What Zinc does & food sources

Zinc supports immune function, wound healing, taste and smell, and many enzyme systems.

Common food sources:

  • Meat and shellfish (especially oysters)
  • Beans and lentils
  • Nuts and seeds
  • Whole grains

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

Ask about zinc status if you take an associated medication long-term and notice slow wound healing, frequent infections, or taste changes — a clinician can decide whether testing or an empiric plan makes sense.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

Zinc competes with copper for absorption — long-term, higher-dose zinc without medical guidance can cause copper deficiency. Zinc also binds some antibiotics in the gut, so dose timing matters.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: Keep zinc doses moderate and time them away from interacting medications — ask your pharmacist.

Learn more about this nutrient: Zinc — uses, safety & interactions

References (1)
  1. Watkins DW, Khalafi R, Cassidy MM, Vahouny GV. Alterations in calcium, magnesium, iron, and zinc metabolism by dietary cholestyramine. Dig Dis Sci 1985;30:477-82.. PubMed

FOLIC ACID

Moderate Depletion

CHOLESTYRAMINE (Questran)

Cholestyramine might interfere with folic acid absorption and reduce serum folate levels.

Cholestyramine reduces folic acid absorption. It can lower serum and red blood cell folate levels in children taking large doses (0.2 to 1.1 grams/kg/day) for several months. There aren't any reports of deficiency in adults. Encourage patients to maintain a good dietary intake of folic acid. For information on foods that are rich in folate, see our chart.
Taking Cholestyramine? Monitor for depletion; a supplement is needed for some patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Folic acid is a B vitamin your body uses to build healthy cells, including red blood cells and the cells that repair tissue. Cholestyramine works by binding things in your gut to carry them out of the body, and folate can get caught up in that process, leaving less available for your system to absorb. The evidence here is rated moderate, and in adults no actual deficiencies have been reported, though high doses in children over several months have shown measurable drops in folate levels. Keeping folate-rich foods in your diet is a reasonable step, and if you have been on cholestyramine long term it is worth asking your pharmacist or doctor whether your levels should be checked.

What Folic acid (folate) does & food sources

Folate is needed for cell division, red blood cell formation, and healthy fetal development.

Common food sources:

  • Leafy green vegetables
  • Beans, lentils, and peas
  • Fortified grains and cereals
  • Citrus fruits

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

Ask your provider whether folate monitoring or supplementation is appropriate for you — this matters most before and during pregnancy, and with long-term use of certain seizure or arthritis medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

Folate needs are individual. With some medications (for example, methotrexate), folic acid is often prescribed deliberately on a specific schedule — follow your prescriber's instructions rather than adding your own.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: High-dose folic acid can mask vitamin B12 deficiency, so the two are often evaluated together.

Learn more about this nutrient: Folic Acid — uses, safety & interactions

References (1)
  1. West RJ, Lloyd JK. The effect of cholestyramine on intestinal absorption. Gut 1975;16:93-8. PubMed

VITAMIN A

Moderate Depletion

BILE ACID SEQUESTRANTS

Bile acid sequestrants may reduce absorption of vitamin A.

By reducing absorption of dietary fats, cholestyramine (Questran) and colestipol (Colestid) may also reduce absorption of fat-soluble vitamins such as vitamin A. Some studies have reported a fall in serum vitamin A levels, but they rarely fall below the normal range with therapy of up to 2 years' duration. Since some of the vitamin A in plasma is carried on lipids, part of this fall in plasma vitamin A levels may be due to decreased plasma lipid levels. Other studies have reported no change in plasma vitamin A levels with colestipol, up to 30 grams/day for 6 months, or cholestyramine 12 to 24 grams/day for up to 10 years. Routine vitamin A supplements aren't necessary in people taking bile acid sequestrants, but check vitamin A levels in people taking high doses for more than 2 years. For information on foods that are rich in vitamin A, see our chart.
Taking Cholestyramine? Monitor for depletion; a supplement is needed for some patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Vitamin A supports your vision, immune system, and skin, and cholestyramine can make it harder for your body to absorb it. This medication works by binding bile acids in your gut to lower cholesterol, but that process also disrupts how dietary fats are absorbed, and vitamin A is a fat-soluble vitamin that hitches a ride on those fats. The good news is that most people taking cholestyramine do not develop a true deficiency, and studies show levels rarely drop below the normal range. If you have been on a high dose for more than two years, though, it is worth asking your doctor or pharmacist whether checking your vitamin A level makes sense.

What Vitamin A does & food sources

Vitamin A supports vision, immune function, and skin health.

Common food sources:

  • Liver and fish oils
  • Dairy and eggs
  • Orange and yellow vegetables (as beta-carotene)
  • Leafy greens

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

Ask your provider before supplementing vitamin A — status testing is not routine, and intake from food plus multivitamins is often already adequate.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

Vitamin A is fat-soluble and accumulates; excess is harmful (and dangerous in pregnancy). Prefer food sources unless a clinician advises otherwise.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: Avoid high-dose vitamin A in pregnancy or when trying to conceive unless a clinician directs it.

Learn more about this nutrient: Vitamin A — uses, safety & interactions

References (8)
  1. West RJ, Lloyd JK. The effect of cholestyramine on intestinal absorption. Gut 1975;16:93-8. PubMed
  2. Elinder LS, Hadell K, Johansson J, et al. Probucol treatment decreases serum concentrations of diet-derived antioxidants. Arterioscler Thromb Vasc Biol 1995;15:1057-63. PubMed
  3. Schwarz KB, Goldstein PD, Witztum JL, et al. Fat-soluble vitamin concentrations in hypercholestrolemic children treated with colestipol. Pediatrics 1980;65:243-50.
  4. Tonstad S, Silverstein M, Aksnes L, Ose L. Low dose colestipol in adolescents with familial hypercholesterolemia. Arch Dis Child 1996;74:157-60.
  5. Schade RWB, van't Laar A, Majoor CLH, Jansen AP. A comparative study of the effects of cholestyramine and neomycin in the treatment of type II hyperlipoproteinemia. Acta Med Scand 1976;199:175-80..
  6. Glueck CJ, Tsang RC, Fallat RW, Scheel D. Plasma vitamin A and E levels in children with familial type II hyperlipoproteinemia during therapy with diet and cholestyramine resin. Pediatrics 1974;54:51-5.. DOI
  7. Probstfield JL, Lin TL, Peters J, Hunninghake DB. Carotenoids and vitamin A: the effect of hypocholesterolemic agents on serum levels. Metabolism 1985;34:88-91. PubMed
  8. Lipid Research Clinics Program. The Lipid Research Clinics' Coronary Primary Prevention Trial Results: 1. Reduction in incidence of coronary heart disease. JAMA 1984;251:351-64. DOI

VITAMIN D

Moderate Depletion

CHOLESTYRAMINE (Questran)

High-dose or prolonged therapy with cholestyramine might reduce blood levels of vitamin D.
Cholestyramine can reduce absorption of vitamin D. Occasionally this leads to osteomalacia, usually in patients receiving cholestyramine in doses above 32 grams daily, or prolonged therapy over 2 years, and with additional risk factors such as ileal resection or primary biliary cirrhosis, which deplete the bile acids needed for vitamin D absorption. Supplements of vitamin D, and sometimes calcium, are necessary in these patients. Use of cholestyramine (24 grams daily) for treatment of hyperlipidemia in otherwise healthy men doesn't seem to affect vitamin D and calcium levels, and supplements aren't necessary.
Taking Cholestyramine? Monitor for depletion; a supplement is needed for some patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Vitamin D is something your bones, muscles, and immune system genuinely depend on, so keeping levels in a healthy range matters. Cholestyramine works by binding things in your gut, and unfortunately it can grab fat-soluble vitamins like vitamin D along the way, reducing how much your body actually absorbs. For most people taking standard doses, this is not a major concern, but if you have been on cholestyramine long-term or at higher doses, it is worth asking your pharmacist or doctor whether your vitamin D level should be checked.

What Vitamin D does & food sources

Vitamin D helps the body absorb calcium and supports bone, muscle, and immune health.

Common food sources:

  • Fatty fish (salmon, mackerel)
  • Fortified milk and cereals
  • Egg yolks
  • Sunlight exposure (the main natural source)

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

A 25-hydroxyvitamin D blood test is the standard way to assess status — ask whether it is appropriate if you take an associated medication long-term, have limited sun exposure, or have bone concerns.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

Vitamin D dosing varies a lot between people; some medications change how vitamin D is processed. Your provider can target a dose to your level instead of guessing.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: Vitamin D is fat-soluble and can accumulate — very high doses over time can cause harm, so follow a clinician-guided plan.

Learn more about this nutrient: Vitamin D — uses, safety & interactions

References (5)
  1. Knodel LC, Talbert RL. Adverse effects of hypolipidaemic drugs. Med Toxicol 1987;2:10-32. PubMed
  2. Compston JE, Horton LW. Oral 25-hydroxyvitamin D3 in treatment of osteomalacia associated with ileal resection and cholestyramine therapy. Gastroenterology 1978;74:900-2. DOI
  3. Compston JE, Thompson RP. Intestinal absorption of 25-hydroxyvitamin D and osteomalacia in primary biliary cirrhosis. Lancet 1977;1:721-4. PubMed
  4. Heaton KW, Lever JV, Barnard RE. Osteomalacia associated with cholestyramine therapy for post-ileectomy diarrhea. Gastroenterology 1972;62:642-6.
  5. Hoogwerf BJ, Hibbard DM, Hunninghake DB. Effects of long-term cholestyramine administration on vitamin D and parathormone levels in middle-aged men with hypercholesterolaemia. J Lab Clin Med 1992;119:407-11.

VITAMIN K

Moderate Depletion

BILE ACID SEQUESTRANTS

Bile acid sequestrants might decrease the absorption and levels of vitamin K.

By reducing absorption of dietary fats, bile acid sequestrants may also reduce absorption of fat-soluble vitamins such as vitamin K. Some studies have found no changes in vitamin K levels or prothrombin times after up to 2 years of bile acid sequestrant use. However, there are a few case reports of hypoprothrombinemia and bleeding, usually in people with other risk factors.
Taking Cholestyramine? Monitor for depletion; a supplement is needed for some patients. ⓘ
Dr. Brian Staiger, Pharm.D explains

Vitamin K is something your blood needs to clot properly, and cholestyramine can interfere with how much of it your body absorbs. This medication works by binding to bile acids in your gut, which disrupts fat digestion overall, and because vitamin K is a fat-soluble vitamin, it gets caught in that same absorption problem. Most long-term users do fine, but there are a handful of reported cases of bleeding, especially in people who already had other risk factors. If you have been on cholestyramine for a while, it is worth asking your doctor or pharmacist whether your vitamin K status should be checked.

What Vitamin K does & food sources

Vitamin K is required for normal blood clotting and contributes to bone health.

Common food sources:

  • Leafy green vegetables (spinach, kale, broccoli)
  • Vegetable oils
  • Fermented foods like natto

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

What to discuss with your clinician

If you take warfarin, vitamin K intake is a central part of your therapy — consistency matters more than avoidance. Discuss any planned change in vitamin K intake (diet or supplements) with the clinic that manages your INR.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Supplement considerations

Never start or stop a vitamin K supplement on your own if you take warfarin — it directly changes how the medication works.

Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

Caution: Vitamin K interacts with warfarin: keep intake consistent and involve your anticoagulation clinic in any change.

Learn more about this nutrient: Vitamin K — uses, safety & interactions

References (5)
  1. West RJ, Lloyd JK. The effect of cholestyramine on intestinal absorption. Gut 1975;16:93-8. PubMed
  2. Schwarz KB, Goldstein PD, Witztum JL, et al. Fat-soluble vitamin concentrations in hypercholestrolemic children treated with colestipol. Pediatrics 1980;65:243-50.
  3. Schade RWB, van't Laar A, Majoor CLH, Jansen AP. A comparative study of the effects of cholestyramine and neomycin in the treatment of type II hyperlipoproteinemia. Acta Med Scand 1976;199:175-80..
  4. Knodel LC, Talbert RL. Adverse effects of hypolipidaemic drugs. Med Toxicol 1987;2:10-32. PubMed
  5. Vroonhof K, van Rijn HJ, van Hattum J. Vitamin K deficiency and bleeding after long-term use of cholestyramine. Neth J Med 2003;61:19-21.
Important

This tool is educational and is not a substitute for professional medical advice. An association is not a diagnosis and does not mean a deficiency will occur. Always talk to your pharmacist or healthcare provider before starting, stopping, or changing any medication or supplement.

Disclaimer: This checker finds which nutrients might be depleted by prescription or over-the-counter medications. Each nutrient depletion issue is rated based on clinical significance. Use your own professional judgment prior to making clinical decisions.

© 2026 Therapeutic Research Center Licensed records refresh weekly · last updated July 3, 2026.
Keep exploring

More about Cholestyramine

Understand the basics

What drug-induced nutrient depletion means

Some medications can, over time, lower the levels of certain vitamins, minerals, or other nutrients — through reduced absorption, increased loss, or changes in how the body uses them.

Association is not deficiency

An entry here means a depletion has been reported or studied — not that it happens to everyone, or that you are deficient. Dose, duration, diet, and your own health all matter.

Evidence varies by pair

Some drug–nutrient links (like metformin and vitamin B12) are well studied; others rest on limited or preliminary research. Each entry shows the evidence rating from our licensed clinical database.

When to ask about labs

If you take an associated medication long-term, ask your healthcare provider whether monitoring is appropriate for you. Not everyone needs testing — your provider can weigh your dose, duration, and symptoms.

Don't self-supplement blindly

Supplements are not risk-free: some can interact with medications, and some (like potassium or magnesium) can be risky with kidney disease. Talk to your pharmacist before adding anything.

Never stop a medication over this

These medications are prescribed for good reasons, and the benefit usually far outweighs a manageable nutrient consideration. Any change belongs in a conversation with your prescriber.

Food first, usually

For many nutrients, a varied diet covers the gap. Each entry lists common food sources; a supplement is a decision to make with your pharmacist or provider, not a default.

Common questions

Cholestyramine & nutrients: FAQs

Does Cholestyramine deplete BETA-CAROTENE?
Cholestyramine has been associated with lower BETA-CAROTENE levels in the clinical literature — see the evidence rating and details above. An association is not a guarantee: dose, duration, diet, and your own health all matter. If you take Cholestyramine long-term, ask your healthcare provider whether checking your BETA-CAROTENE status is appropriate.
Should I take a supplement because I take Cholestyramine?
Not automatically. The right first step is usually a conversation with your pharmacist or provider — they can weigh your dose and duration, decide whether testing makes sense, and recommend food-first strategies or a supplement if genuinely needed. Some supplements can interact with medications, so do not add one without checking.
Should I stop taking Cholestyramine?
No — never stop a prescribed medication because of a nutrient association. Cholestyramine is prescribed for good reasons, and nutrient considerations are usually manageable with monitoring or diet. Any change to your medication belongs in a conversation with your prescriber.
Where does this information come from?
The depletion records come from the Natural Medicines (Therapeutic Research Center) database — an evidence-graded clinical reference — and are displayed as published, with their citations. The plain-English context is written and reviewed by licensed HelloPharmacist pharmacists.

Questions about Cholestyramine and your nutrition?

Ask a licensed pharmacist — free, no appointment needed.

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Sources

Sources & How We Checked

Nutrient depletion records for Cholestyramine are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.