Summary of
Interactions with Vitamins, Herbs, and Foods
In some cases, an herb or supplement may appear in more than one category, which may seem
contradictory. For clarification, read the full article for details about the summarized
interactions.
May Be Beneficial:Depletion or
interference—The medication may deplete or interfere with the absorption or
function of the nutrient. Taking these nutrients may help replenish them.
Zinc
May Be Beneficial:Side effect
reduction/prevention—Taking these supplements may help reduce the likelihood and/or
severity of a potential side effect caused by the medication.
Iron
Avoid:Adverse interaction—Avoid these supplements when taking this
medication because taking them together may cause undesirable or dangerous results.
High-potassium foods*
Potassium supplements*
Salt substitutes*
Supportive interaction
None known
Reduced drug
absorption/bioavailability
None known
An asterisk (*) next to an item in the summary indicates that the
interaction is supported only by weak, fragmentary, and/or contradictory scientific
evidence.
Interactions with Dietary Supplements
Potassium
An uncommon yet potentially serious side effect of taking ACE inhibitors is increased blood
potassium levels.123 This problem is more likely to occur
in people with advanced kidney disease. Taking potassium supplements,4
potassium-containing salt substitutes (No Salt®, Morton Salt Substitute®, and
others),567 or large amounts of high-potassium foods at the
same time as ACE inhibitors could cause life-threatening problems.8 Therefore,
individuals should consult their healthcare practitioner before supplementing additional
potassium and should have their blood levels of potassium checked periodically while taking
ACE inhibitors.
Zinc
Preliminary research has found significant loss of zinc in urine triggered by taking
captopril.9 In this trial, depletion of zinc reduced red blood cell levels of zinc.
Although details remain unclear, it now appears that chronic use of captopril may lead to a
zinc deficiency.10
It makes sense for people taking captopril long term to consider taking a zinc supplement
or a multimineral tablet containing zinc as a
precaution. (Such multiminerals usually contain no more than 99 mg of potassium, probably not
enough to trigger the above-mentioned interaction.) Supplements containing zinc should also
contain copper, to protect against a
zinc-induced copper deficiency.
Iron
In a double-blind study of patients who had developed a cough attributed to an ACE inhibitor,
supplementation with iron (in the form of 256 mg of ferrous sulfate per day) for four weeks
reduced the severity of the cough by a statistically significant 45%, compared with a
nonsignificant 8% improvement in the placebo group.11
References (To view, roll mouse over the "References" heading; to hide, click on the heading)
1. Good CB, McDermott L, McCloskey B. Diet and serum potassium in
patients on ACE inhibitors. JAMA 1995;274:538.
2. Rush JE, Merrill DD. The Safety and tolerability of lisinopril in
clinical trials. J Cardiovasc Pharmacol 1987;9(Suppl 3):S99–107.
3. Sifton DW, ed. Physicians’ Desk Reference. Montvale,
NJ: Medical Economics Company, Inc., 2000, 1965–8.
4. Burnakis TG, Mioduch HJ. Combined therapy with captopril and potassium
supplementation. A potential for hyperkalemia. Arch Intern Med
1984;144:2371–2.
6. Ray K, Dorman S, Watson R. Severe hyperkalemia due to the concomitant
use of salt substitutes and ACE inhibitors in hypertension: a potentially life threatening
interaction. J Hum Hypertens 1999;13:717–20.
7. Sifton DW, ed. Physicians’ Desk Reference. Montvale,
NJ: Medical Economics Company, Inc., 2000, 1965–8.
8. Stoltz ML. Severe hyperkalemia during very-low-calorie diets and
angiotensin converting enzyme use. JAMA 1990;264:2737–8 [letter].
9. Golik A, Modai D, Averbukh Z, et al. Zinc metabolism in patients
treated with captopril versus enalapril. Metabolism 1990;39:665–7.
10. Golik A, Zaidenstein R, Dishi V, et al. Effects of captopril and
enalapril on zinc metabolism in hypertensive patients. J Am Coll Nutr
1998;17:75–80.
11. Lee SC, Park SW, Kim DK, et al. Iron supplementation inhibits cough
associated with ACE inhibitors. Hypertension 2001;38:166–70.
The information presented in Healthnotes is for informational purposes
only. It is based on scientific studies (human, animal, or in vitro), clinical
experience, or traditional usage as cited in each article. The results reported may not
necessarily occur in all individuals. For many of the conditions discussed, treatment with
prescription or over the counter medication is also available. Consult your doctor,
practitioner, and/or pharmacist for any health problem and before using any supplements or
before making any changes in prescribed medications. Information expires June 2009.
