When it comes to certain nutrients, more isnt better.
And they can often fill in any deficiencies in your diet.
But taking large doses of some of themparticularly over a long period of timeis not the answer.
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In fact, certain vitamins and minerals can be toxic when taken in excess.
Achieving your nutrient intake through diet is a first-line approach.
But taking megadoses of vitamins, unless medically prescribed and supervised by a professional, is not the answer.
Anything ingested in excess of what your body needs is excreted through your urine.
Taking large doses of fat-soluble supplements is more likely to cause toxic effects.
Can Taking Large Amounts of Supplements Cause Toxicity?
Side effects range from mild symptoms like headaches, toin the most severe instancesdeath.
Optimal intake is also important in maintaining liver and heart health.
One egg, for example, provides 75 mcg RAE of vitamin A.
There are no established upper limits for beta carotene or other sources of provitamin A.
In severe cases it can lead to coma and death.
When used during pregnancy, too much vitamin A may cause birth defects.
(Although too much might make your skin turn yellow, which will resolve once consumption drops down.)
The RDA for vitamin D is 600 IUor 15 mcgfor people ages 14 to 70.
And there are various reasons why it’s commonly taken as a supplement.
The amount you need will vary depending on how low your blood levels are.
But because vitamin D is fat-soluble, excess consumption for long periods of time can cause vitamin toxicity.
While rare, it can happen, and usually occurs from supplemental use.
Therefore an individualized approach that is supervised by a medical professional is safest.
Vitamin E
This is a powerful antioxidant that is important for immune, cellular and vascular health.
The natural form of vitamin E is called alpha-tocopherol and the synthetic form is DI-alpha-tocopherol.
Some supplements are sold as mixed tocopherols.
It’s found in green leafy vegetables and can be taken in supplemental form.
It’s set as 120 mcg per day for men 19 and older and 90 mcg for women.
There’s no set UL for vitamin K, because there is limited evidence of toxicity.
The RDA for vitamin B6 is 1.3 mg daily for adults ages 19 to 50.
The UL of 100 mg a day is much lower than dosages associated with adverse effects.
Iron
Iron is a mineral and an essential component of hemoglobin.
It supports muscle metabolism and is necessary for physical and neurological development, cellular functioning and oxygen transport.
Heme iron has a higher bioavailabilitymeaning that’s more readily absorbed by the body.
The RDA for iron is 8 mg for males ages 19 to 50 and 18 mg for adult women.
Iron needs increase during pregnancy and lactation.
The ODSnotes that supplemental iron (25 mg) can reduce zinc absorption.
This dosage is commonly found in supplements and may be suggested to treat a deficiency.
But this should be under the supervision of a professional.
And high-dose supplementation can increase the risk of constipation, nausea, abdominal pain, diarrhea and vomiting.
While these symptoms are not toxic, they are certainly unpleasant.
Zinc
Zinc is required to activate certain immune cells and acts as a powerful antioxidant.
It is also important in wound healing.
Zinc deficiency is associated with impaired immune function and increased risk of infections in certain groups.
The UL is 40 mg a day for males and females ages 19 to 50.
Long-term zinc supplementation can result in a copper deficiency.
However, there are times when supplementation is necessary.
Regulated supplementation can be used to meet nutrient requirements or to treat a deficiency.
If you fit into one of these groups, you may need supplementation.
Independent verification companies like NSF, USP and ConsumerLab are independent organizations that review the manufacturing process of products.
This can include product testing and facility audits.
Certain populations are at a greater risk of developing insufficiencies and deficiencies.
However, high-dose supplements without medical supervision, especially fat-soluble vitamins, can be toxic.
High doses of zinc can inhibit copper absorption, and too much iron can decrease zinc absorption.
Copper deficiency may cause anemia, high cholesterol, osteoporosis and increased risk of infection.
In addition, the absorption of iron can be inhibited by calcium supplements.
