Supplementary Cautions

46% of households in the UK regularly buy supplements. Many of these supplements are very safe to use when the recommended dose and instructions are followed but even the most popular supplements have some contra-indications.  A contra-indications is a condition or factor which means the supplement may not be beneficial or could even be harmful, so it is important to be aware of any contra-indications the supplements you use may have. As many supplements are now available off the supermarket shelf or internet users maybe missing out on the invaluable professional advice that a specialist health store, pharmacist, nutritionalist or herbalist would offer.If you have health conditions or take prescription medications then professional advice should always be sought.

Some Cautions for popular supplements


This generally very safe supplement should usually be taken with magnesium as the two minerals work in harmony together. As calcium is the main constituent of kidney stones it should not be taken on its own without medical approval where there is a history or risk of this condition. Where it is taken with approval from a professional then taking the supplement at mealtimes reduces the risk. Anyone suffering or with a history of cancer, hyperparathyroidism or sarcoidosis should also seek medical advice before taking calcium. There are certain medications that calcium may interfere with the absorption of. They are:Calcium channel blockers ,Terracycline and fluoroquinolone ,antibiotics ,Thyroid hormone and therefore calcium should only be taken with medical advice and even then at a different time of day to the medications.Calcium is best taken in the evening.

St Johns WortThis very effective herb for mild to moderate depression is used by millions worldwide. Recent research concluded that the herb was at least as effective as anti-depressant drugs and is now classified as prescription medication in some countries.The caution for St Johns Wort is that it interacts with other drugs causing them to metabolise through the body too quickly. This is obviously very significant for people on the contraceptive pill or the blood-thinning drug warfarin, who are at risk of a stroke. The Medicines Control Agency issued a warning on March 1st 2000 that patients who are on a long list of drugs should stop taking St John's wort until they have consulted their GP or pharmacist. Medications for asthma, epilepsy, depression, migraine and heart problems are all implicated. Hypericin, the active ingredient in St John's wort, reacts with sunlight and so those taking the remedy should limit their unprotected sun exposure. This is particularly significant for people who suffer from seasonal affective disorder, who might combine a course of St John's wort with light-box therapy.


This very popular supplement is a real joint saver and protector but is in most cases derived from shellfish. This makes it unsuitable for vegetarians and anyone with a shellfish allergy or intolerance. There are now vegetarian forms of Glucosalmine not from shellfish available in good health food shops. Glucosalmine however is generally well tolerated and no adverse reactions with medications reported

Gingko Biloba

This popular supplement is used to improve the circulatory flow Â? especially to the peripherals arms, legs and brain. Similar to aspirin it can help reduce the Â?stickinessÂ? of the blood. Because of this effect it makes it unsuitable for anyone on blood thinning medication such as high dose aspirin, warfarin and trental.


Iron as a stand alone supplement  should only be taken on medical advice for anemia. As part of a multi vitamin mineral it is usually safe. Iron supplements especially those in the form of ferrous sulphate or ferrous fumate can cause constipation. Gentler forms of iron can be found in the supplement Spatone ( ironised water) or black strap mollasses. Iron supplements may also interfere with the absorption of antibiotics and other meds so be sure to tell your Gp when medications are prescribed. Iron supplements are also contra-indicated with Addisons Disease and hemochromatosis.


Liquorice is a good adrenal gland stimulant and used for those who have adrenal fatigue, hormone problems, inflammation and as an immune boost. However it can raise blood pressure so anyone with even a slightly raised blood pressure should avoid this supplement. Deglycerized liquorice does not raise blood pressure.

Vitamin A

Supplements above 2000iu of vitamin A are not advised in pregnancy because of the risk of feotal damage at high doses. It is therefore advised that pregnant women should only supplement vitamin A on advice. However in the form of betacarotene or mixed caratonoids the amounts usually found in multi are generally safe. Remember to check all the supplements you take as some supplements such as cod liver oil also contain Vitamin A.Some studies have linked taking beta cartene or vitamin A supplements for smokers to an increased risk of lung cancer. Until clearer research is done it is advised that smokers do not take vitamin A or beta carotene supplements.

Vitamin C

While vitamin C is generally non-toxic,as it cannot be stored in the body, in high doses (more than 2,000 mg daily) it can may cause diarrhea, gas, or stomach upset. Those with kidney problems should get advice before using vitamin C as it may increase the risk of kidney stones . Certain medications  may not interact well with higher doses of vitamin C :such as Acetominophen  ,Loop Diuretics, Beta-blockers for high blood pressure , and Warfarin so check with a professional first


You can obtain advice about supplements and medications from a nutritionist, a good pharmacist or trained staff at your local health food shop. 

About the author:

Donna Milligan is a Nutritional and Scio Bioresonance therapist who helps her clients with a range of conditions from IBS, skin and hormonal issues to allergy , mild depression and fatigue among others . Her consultations include Wellness MOTS, Allergy/Intolerance Analysis and Menopause Naturally Consultations as well as postal nutritional consults. Specialises in making programmes suitable for the individual.More info at or call 01234 838880


Author: Donna Milligan
Copyright © 2023 Donna Milligan. All rights reserved

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