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Mineral Toxicity

The following minerals are addressed below:


Do not take if you have: allergies to calcium or antacids, high blood-calcium levels, or sarcoidosis.

Consult your doctor if you have: kidney disease, chronic constipation, colitis, diarrhea, stomach or intestinal bleeding, irregular heartbeat, or heart problems or high blood pressure for which you are taking a calcium channel blocker.

Excessively high intakes of calcium can interfere with the absorption of zinc, magnesium, iron, phosphorus and other nutrients. When calcium in the body is too high compared to magnesium, excess calcium may be deposited in the soft tissues. This may result in calcium deposits in places such as the kidneys, the arteries and the heart.

Signs of toxicity can also include: confusion, slow or irregular heart beat, bone or muscle pain, nausea and vomiting.


Toxicity is rare but there is potential for iron toxicity because very little iron is excreted from the body. Thus, iron can accumulate in body tissues and organs when normal storage sites are full.

Doses of iron prescribed for iron deficiency anemia in adults are associated with constipation, nausea, vomiting, and diarrhea, especially when the supplements are taken on an empty stomach.


Magnesium toxicity is not a concern for most healthy people. However, people with kidney disease may develop toxicity. This is because the kidneys are responsible for regulating the level of magnesium in the blood. Symptoms of magnesium toxicity include: weakness, nausea, and malaise (general discomfort and weakness or an "out-of-sorts" feeling).

Very rarely symptoms of excess include, flushing of the skin, low blood pressure, thirst and shallow breathing.


Zinc is considered to be non-toxic, although very high doses may cause nausea, vomiting and diarrhea.


Boron may be toxic in doses above 100 mg. Symptoms of toxicity include: a red rash, vomiting, diarrhea, reduced circulation, and shock and then coma.


Excessive amounts of cobalt can cause nausea and damage the heart, kidneys and nerves.


Toxicity is rare as less than 10% of the chromium taken into the body is actually absorbed.

Some people experience troubling dreams when taking chromium supplements.


Intakes in excess of 10 mg can cause vomiting, diarrhea, muscular pain, depression, irritability, nervousness and dementia.

Toxicity is low and very rare.

Zinc and copper should not be taken at the same time (take them some hours apart) unless in the form of a well balanced multivitamin and mineral supplement.


Iodine is toxic in high doses and may aggravate or cause acne.

Large doses may interfere with hormone functioning.


Toxicity is rare, but its symptoms may include: lethargy, involuntary movements, posture problems and eventually coma. Manganese is one of the least toxic trace mineral as it is readily excreted from the body.


Molybdenum is toxic in doses higher than 10 to 15 mg. It can cause gout like symptoms.

A high intake of copper or ferrous sulphate iron can decrease the absorption of molybdenum by the body.


Toxicity may occur with dosages or food intakes above 1g per day. It may cause diarrhea, calcification of the organs and soft tissues and prevent the absorption of calcium and magnesium.

Long term imbalances between calcium and phosphorus can cause osteoporosis.


Selenium is toxic in small doses so beware of blackened fingernails and or a garlic-like odor on skin and breath.


Vanadium is very toxic and high quantities are linked to manic depression.

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Bland, J. 1996, Contemporary Nutrition. J & B Associates.

Davies, S. and A. Stewart., 1997, Nutritional Medicine. Pan.

Holden, S., Hudson, K., Tilman, J. & D. Wolf, 2003, The Ultimate Guide to Health from Nature. Asrolog Publication.

Pressman, A. and S. Buff, 2000, The Complete Idiot's Guide to Vitamins and Minerals. (2nd Ed.) Alpha Books.

Soothill, R. 1996, The Choice Guide to Vitamins and Minerals. A Choice Book Publication.

Sullivan, K. 2002, Vitamins and Minerals: A Practical Approach to a Health Diet and Safe Supplementation. Harper Collins.

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Note that we are not concerned here with specific subclassifications, such as mineral or trace element. These are all still minerals and we simply want to consider issues related to toxicity.

For further details, please see our site section related to minerals and deficiencies.


The most effective multi-vitamin and mineral supplements have been formulated with appropriate balance and enable a synergistic benefit with safety assured.

There are none of the risks associated with mega-doses that hope some will survive the stomach to be absorbed in the intestine. This formulation ensures absorption and eliminates waste.

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