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Supplement Savvy for Cancer: B Vitamins

By Jill Place, MA, RD

What They Are . . .

B vitamins are eight related water-soluble vitamins also called B-complex vitamins.  Water-soluble means they dissolve in water.  Vitamins are organic molecules that act as catalysts in your body.  A catalyst is a substance that helps a chemical reaction happen faster and easier than normal.  Without these vitamin catalysts, there may be vitamin deficiencies that can lead to abnormal body functioning and diseases like cancer.

B vitamins include thiamin (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), folic acid (B9), cyanocobalamin (B12), pantothenic acid, and biotin.  We get B vitamins from leafy green vegetables, fruit, fish, milk, meat, rice, whole-grain cereals, soy, and many other foods.  Friendly bacteria in the intestines also make some B vitamins.

What They Do . . .

Thiamin plays a part in the digestion of carbohydrates like apples, rice, milk, and doughnuts, and may also have antioxidant properties.

Riboflavin protects Vitamin E from oxidizing and forming free radicals.  Free radicals are atoms with an odd number of electrons.  These electrons want to pair up with other electrons.  So they run around trying to find another electron to marry.  While they’re running around, they can cause damage to DNA or cell membranes.  This damage may cause cancer.   Antioxidants marry with free radicals and stop them from doing damage.  Not having enough Riboflavin may cause esophageal cancer.

Niacin in its niacinamide form may have antioxidant activity.  Niacin deficiency may cause DNA damage. Niacin also regulates the p53 gene, which protects against DNA damage and stops normal cells from becoming cancer cells.  Niacinamide doesn’t cause the flushing that most people equate with niacin.

B6 helps over 100 enzymes do their work of digesting food in your body.  B6 deficiency can frequently occur with cancer.  Deficiency may cause your immune system to not work well and also cause peripheral neuropathy, which is tingling or pain mostly in your arms and legs.  B6 can also be a treatment for nausea following radiation.  B6 has been shown to stop melanoma growth.

Folic Acid or Folate is found in dark green leafy vegetables, beans, orange juice, liver, and brewer’s yeast. Folate deficiency has been associated with lung, esophageal, brain, cervical, breast, and especially colorectal cancer.  Folate participates in a very important in a process that affects the health of your DNA called methylation.  Not enough DNA methylation may cause cancer.  It’s been suggested that high levels of Folate might cause cancer, so ask your dietitian what a safe amount might be to take.  Food Folate is only 50% absorbed, while folic acid supplements taken on an empty stomach are mostly absorbed, and Folic Acid taken with food allows almost twice as much Folate to be absorbed.  So take your Folate supplements, and B-Complex supplements, with a meal.  And don’t take too much.

B12 deficiency can cause peripheral neuropathy, which is tingling or pain mostly in your arms and legs.  If you’ve had gastric surgery, you might have a B12 deficiency, so using a supplement might be a good idea.  B12 deficiency has also been identified as a risk fact for breast cancer.  A combination of B12 and Folic Acid may also reduce the risk of lung cancer, even in heavy smokers.

Pantothenic Acid, also known as Vitamin B5, is found in organ meats like liver, egg yolks, cashew nuts, brown rice, lentils, soy, broccoli, and milk.  Pantothenic Acid stops free radical from forming in fats. Because of this, Pantothenic Acid has antioxidant activity.

Biotin is found in abundance in Brewer’s yeast, and also in organ meats, milk, and soy.  Biotin helps in the metabolism of fats, proteins, and carbohydrates in your body.  It also plays a role in gene expression.

What To Do . . .

 If you have a deficiency of one or several B Vitamins, your doctor may have to prescribe supplements for you.  If you have no deficiency and want to try B Vitamins for tingling or pain, it might be a good idea to take them in   a combined   B-Complex   form or in a Multivitamin.  The B-Complex form is more appropriate during chemotherapy and radiation.  It’s not a good idea to take Multivitamins during treatment as the antioxidants contained in them may make your treatment less effective.  Ask your   dietitian or    Supplement    Savvy    Specialist    to recommend a quality B-Complex or Multivitamin brand for you.

What To Watch Out For . . .

Thiamin is generally well-tolerated.  Loop diuretics like furosemide may cause deficiency.  Antithiamin factors, or substances that inactivate Thiamin, are sulfite-containing foods like wine and dried fruit, tea, and coffee.

Riboflavin is also well-tolerated.  Many drugs decrease absorption, such as cholestyramine, chloropromazine, colestipol, metoclopramide, nucleoside reverse-transcriptase inhibitors, oral contraceptives, probenecid, quinacrine, and amitriptyline and other trycyclic antidepressants.  Supplements may turn urine a bright yellow-orange.

Niacin shouldn’t be taken in high doses if you have liver disease, peptic ulcer disease, gastritis, gallbladder disease, diabetes, or gout.  There are few drug interactions;  using niacinamide with carbamazepine will allow this drug to stay in your body longer than normal. 

B6 shouldn’t be taken by pregnant women and nursing mothers in doses greater than 20 mg.  If you’re taking levodopa without carbidopa or amiodarone, you shouldn’t take more than 5 mg.  Neuropathy, nausea, vomiting, and abdominal pain may occur with high doses.  Drugs like carbamazepine, cycloserine, ethionamide, hydralazine, isoniazid, oral contraceptives, penicillamine, and valproic acid decrease B6 levels and may lead to deficiency.  B6 may affect the absorption of phenytoin, phenelzine, phenobarbital, and theophylline. 

Folate shouldn’t be taken in high doses if you have anemia.  Drugs such as anticonvulsants, cholestyramine, colestipol, colchicine, NSAIDS, phenytoin, and sulfasalazine may reduce absorption.  Folate may enhance the actions of fluoxetine, lithium, lometrexol and Vitamins B6 and B12.  Folate can counteract high homocysteine levels sometimes seen with metformin.   Folate can also reduce the side effects of methotrexate.

B12 shouldn’t be used by pregnant women and nursing mothers in doses greater than 12 mcg, and those with anemia because of a Folate deficiency shouldn’t use more than 10 mcg.  Drug such as cholestyramine, colchicine, colestipol, metformin, nitrous oxide, para-aminosalicylic acid, and proton pump inhibitors like omeprazole decrease B12 absorption.  Calcium, Folate, and Vitamin B6 enhance absorption.  Hydroxycobalamin should be used instead of cyanocobalamin for those whose have Leber’s optic atrophy.

Pantothenic Acid shouldn’t be used by pregnant women or nursing mothers in doses greater than 10 mg a day.  Dexpanthenol, a form or Pantothenic Acid, shouldn’t be used by those who develop a rash with topical use (Dexpanthenol is in many cosmetic products) or shouldn’t be used orally if you have an obstruction or hemophilia.   There are no other drug interactions.  High doses of Pantothenic acid may inhibit the absorption of Biotin.  That’s one of the reasons why it’s important to have a balanced B-Complex supplement.

Biotin shouldn’t be used by pregnant women and nursing mothers in does greater than 30 and 35 mcg a day respectively.  Antibiotics, anticonvulsants, and high doses of Pantothenic Acid may inhibit absorption.

© Copyright 2002 Jill Place, MA, RD