Manual of Clinical Nutrition

Food and Drug Interactions

Manual of Clinical Nutrition Management II- 32 Copyright © 2013 Compass Group, Inc.

Vitamin
Supplements
Vitamin A
Adequate fat,
protein, and
vitamin E
needed for
absorption 
calories for
carbohydrate
intake; 
thiamin
requirement

Toxic in excess doses

Avoid excessive intake of raw fish

aGI indicates gastrointestinal;  , increase; and , decrease
bNatural licorice contains a corticosteroid pressor substance (carbenoxolone), which can interfere with the effect of antihypertensive medications (beta
blockers/hydralazine /thiazides/spironolactone). Advise patients receiving antihypertensive therapy to eat no more than an occasional piece of natural
licorice. See Section II: Herb and Medication Interaction.

Medication

Classification

Effect of Food

on Medication

Effect of Medication on

Nutritional Status

Patient Guidelines

Thiamin (B 1 )

Niacin (B 3 )

Pyridoxine (B 6 )

Foods high in

thiaminase may

 thiamin

activity

Large doses may  blood glucose

and cause jaundice and GI

disturbances; 3 – 9 g/day produces

toxicity

Take with food or milk to  GI

distress

For capsules, do not mix contents

with jam or jelly

Vitamin C

Vitamin D

Vitamin E

Large doses may  red blood cell

hemolysis and destroy dietary

vitamin B 12 when taken with food

May be relevant to kidney stone

formation

Toxic in excess doses

Large doses may induce vitamin K

deficiency

Take vitamin B-12 supplement

separately by 1 hour

Take with iron supplement to 

iron absorption

Mineral
Supplements
Fluoride

Potassium
(K-Dur, K-Lor,
K-Lyte)

Decreased

absorption when

taken with dairy

products

20 mg/day will produce severe

skeletal fluorosis

Ca, vitamin C, or protein deficiency

will  fluorosis

Do not take with high-fat, low-sugar

(rich) foods

Keep Ca supplement and albumin

hydroxide separate of fluoride by 2

hours

Do not take with dairy products

aGI indicates gastrointestinal;  , increase; and  , decrease

Also find reference to the following medications:

Anticoagulants See Section III: Anticoagulant Therapy

Corticosteroids See Section III: Corticosteroid Therapy

Calcium supplements See Section IF: Nutrition Management of Calcium Intake

Chemotherapeutic agents See Section III: Cancer

Monamine oxidase inhibitors See Section IH: Tyramine Restricted Diet