The Side Effects of Excessive Intake of Vitamins and Minerals

Updated on September 22nd, 2020
side effects of vitamin and mineral supplements

Minerals and Vitamins are marketed to keep you strong and healthy. But few may carry more risks than benefits, especially as we grow old. Supplements are most beneficial when they’re used to replace dietary deficiencies. Therefore, most of us don’t require them.

Such needless use can be harmful, particularly if you also take prescription medicines.

Besides, the evidence supporting supplements is often mixed or flimsy, and because of lax regulation, you can’t always be sure what they have. The following products may be particularly detrimental if you’re older than fifty.

The side effects of vitamin and mineral supplements:

1. Folic acid

Vitamin B9 (Folic acid) has been recommended — but not proved — to help ward off depression, Alzheimer’s disease, and cardiac disease [1].

But a recent study published by the AJCN (American Journal of Clinical Nutrition) relates excess folate (including folic acid) to tingling, burning, or numbness in the extremities of individuals with a common gene variant. The odds were 7 fold higher for those who took more than 800 [micrograms] daily.

Besides, taking as little as 300 mcg per day can mask a B12 deficiency, which is relatively common in senior adults. Undiagnosed, that may lead to cognitive trouble, nerve damage, and even psychiatric problems.

Folic acid may also reduce the effectiveness of the cancer drug methotrexate (Rheumatrex and generic) and seizure drug fosphenytoin (Cerebyx and generic).

Who might need it? Women who plan for pregnancy or pregnant women or to prevent congenital disabilities.

[Also Read: Why Women Needs Folic Acid]

2. Calcium

You might take calcium supplements to power your bones, which can soften with age. But frequent use may spike the risk of kidney stones and possibly heart disease.

A study in the JAHA (Journal of the American Heart Association) found that individuals who took calcium supplements over ten years were more likely than others to accumulate the artery plaque, leading to cardiac arrests. Supplemental calcium may also negatively interact with some thyroid and heart medications.

Who might need it? People who eat no or little calcium-dense food, such as leafy vegetables and dairy products.

3. Iron

Low iron blood levels or anemia, is more common with age. But taking too much iron can mask anemia symptoms, which may be caused by internal bleeding and lead to a wrong diagnosis [2].

Iron supplements may also inhibit the absorption of specific blood-pressure-lowering drugs such as captopril (Capoten and generic) and antibiotics.

And if you are suffering from hemochromatosis, a common genetic condition, iron pills may lead to an overload of the nutrient in critical organs, potentially causing diabetes symptoms, liver damage, and heart problems.

Who might require it? People with iron-deficiency anemia (diagnosed).

4. Vitamin E

These supplements are said by few to help prevent dementia, cancer, and cardiac disease, but there’s little evidence — and plenty of reason to skip them. Studies have linked regular use to a 13 percent higher risk of heart failure in specific populations.

A study published in JAMA’s 2011 issue also found that taking 400 IU international units per day can boost the likelihood of prostate cancer by seventeen percent. Vitamin E supplements can also make some chemotherapy drugs less effective.

Who might need it? Experts don’t recommend it to anyone.

5. Niacin

Niacin plays a role in several metabolic reactions and is necessary for the activity of multiple enzymes. Niacin deficiency results in a pellagra disease that affects the skin, the nervous system, and the digestive tract.

The disease was common in the U.S and regions of Europe in the early 20th century in places where corn, a cereal low in both the amino acid tryptophan and niacin, was a dietary staple (IOM 1998b).

Still, today it has virtually disappeared in the developed globe. Alcoholism is presently the leading cause of niacin deficiency in the U.S, according to the University of Maryland Medical Center (UMM 2013). 

Excess niacin can lead to flushing reactions, itching, tingling, and rashes, reddening of the skin, and nausea. Extra doses can cause liver toxicity, with symptoms such as glucose intolerance, blurred vision, and jaundice (IOM 1998).

In February 2014, a niacin toxicity case was reported after a shipment of enriched rice was apparently accidentally over-fortified by Mars Foodservices, the manufacturer.

The firm recalled its Uncle Ben’s Infused Rice products after teachers and students in some Texas public schools complained of itching rashes, burning, headaches, and nausea 30-to-90 minutes after eating the rice.

Similar instances have occurred in North Dakota and Illinois (FDA 2014d). Mars Foodservices acknowledged in a press release that the illnesses might have been linked to too high niacin levels in its enriched rice (Sun 2014).

6. Zinc

Although no side effects have been found from consuming naturally occurring zinc in food, excessive supplementation has been confirmed to suppress the immune system.

That’s due to zinc interfering with copper absorption, which leads to anemia, copper deficiency, changes in white and red blood cells, and weakened immunity (IOM 2001). In clinical trials, excessive zinc intake has been linked with a significant increase in hospitalization for genitourinary causes (ODS 2013b). 

Adequate mineral and vitamin intake from a balanced diet are essential for maintaining health and preventing diseases caused by dietary deficiencies, such as night blindness in children who lack vitamin A or pellagra (triggered by a shortage of niacin).

Still, at extremely high levels, some nutrients can be toxic. For instance, intaking too much vitamin A during pregnancy can cause severe developmental abnormalities in the fetus. Too much zinc can suppress rather than stimulate the immune system.

Extra doses of niacin can produce symptoms that range from blurred vision and nausea to liver toxicity. 

[Also Read: Foods High in Zinc]

Bottom Line

Several minerals and vitamins have been tested in clinical trials to investigate whether taking massive amounts could prevent cancer and other diseases. Usually, significantly high vitamin levels had no preventive effect and, in some instances, were linked with increased cancer deaths.

The study highlights the importance of sufficient but not excessive intake of minerals and vitamins.

View Comments (0)

Leave a Reply

Your email address will not be published.

Scroll To Top

Sign up for our Newsletter !
Get access to quality &
Natural Health Tips right from the Experts
Subscribe !
Send this to a friend