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Side Effects and Symptoms of Taking Too Many Vitamins

Photo by Dvortygirl. Are you poisoning yourself with vitamins?

Photo by Dvortygirl. Are you poisoning yourself with vitamins?

Vitamins are important, but what happens if you take too many? Even though vitamins are good for you and essential to your health, getting too much of the vitamin can cause negative side effects. You need to know how much you need, how much is dangerous, where to get them, and what they do for your body.

Vitamins Covered in This Article

  1. Vitamin C
  2. Vitamin E
  3. Vitamin D
  4. Vitamin A
  5. Vitamin B
  6. Vitamin K
  7. Iron
  8. Zinc

1. Vitamin C

Benefits: Vitamin C is commonly known for its ability to assist in immune system functioning. Vitamin C is even more important for smokers because it can prevent damage caused by the smoke and free radicals. It also has been said to help maintain skins youthful appearance.

Risks: Vitamin C enhances iron absorption, so high levels can lead to iron poisoning. High levels of vitamin C have also been theorized to increase the risk of miscarriage. Extremely high levels can cause upset stomach and diarrhea.

Sources: red pepper, orange juice, grapefruit juice, kiwi fruit, green pepper, broccoli, strawberries, brussels sprouts, and cantaloupe

2. Vitamin E

Benefits: Vitamin E is very important for protecting the skin against sun damage, pollution, and other free radicals. It contains antioxidant properties. It can be used to treat sunburns, skin aging, age spots, stretch marks, psoriasis and scars. Some studies even show that taking vitamin E above the daily recommended amount can be beneficial in preventing certain ailments. These include menstrual pain, Alzheimer's, asthma, arthritis, breast cancer, and cardiovascular disease.

Risks: An excess amount of vitamin E can cause abnormal bleeding and increase the risk of hemorrhaging, diarrhea, flatulence, bloating, weakness, headache, fatigue, and blurred vision. Extremely high doses of vitamin E for prolonged periods of time have been found to increase risk of death.

Sources: wheat germ oil, sunflower oil, safflower oil, nuts, nut oils, palm oil, avocados, asparagus, broccoli, kiwi fruit and pumpkin.

3. Vitamin D

Benefits: Vitamin D is essential for our body to absorb calcium. Without enough vitamin D, our bones would become very brittle, thin, and oddly shaped.

Risks: Excess amounts of vitamin D can cause a loss of appetite, nausea, vomiting and constipation. Toxic levels of vitamin D, called hypervitaminosis D, causes an over absorption of vitamin D in the intestines, causing calcium to be lost from the bones. This over absorption can also be dangerous because it can cause hypercalcemia, a high amount of calcium in the blood. Too much vitamin D can also lead to depression and cause issues in nerve functioning.

Sources: sunlight, dairy products, eggs, cereal and certain fish.

4. Vitamin A

Benefits: Vitamin A helps your eyes function and react properly to light. Vitamin A also has antioxidative properties that help protect the body from free radicals.

Risks: The effect of taking in too much vitamin A are nausea, vomiting, blurred vision, headache, and dizziness. If you have a surplus of vitamin A for a prolonged period of time, your liver is at risk. This can lead to scarring and deterioration of the liver. This condition is called hypervitaminosis A and is typically caused by supplements instead of food.

Sources: animal livers, carrots, broccoli, sweet potato, butter, kale, spinach, pumpkin, collard greens, cantaloupe and egg.

5. Vitamin B

Benefits: Vitamin B is actually a group of eight different vitamins that make up the vitamin B complex. These vitamins play a very important role in cell metabolism. vitamin B12 keeps nerves and red blood cells healthy. Vitamin B Complex plays an important role in energy production, good digestion, a healthy nervous system, healthy skin, hair, and nails.

Risks: Typically, any excess vitamin B will be excreted in the urine since it is water soluble. However, excess vitamin B3 or niacin can nausea vomiting and glucose intolerance. Skin can also become flushed, itchy, or have a burning sensation. Headaches and increased intracranial blood flow is also common with excess niacin. Extreme excess amounts of vitamin B6 or pyridoxine can result in peripheral sensory neuropathy. Excess vitamin B9 or folic acid can mask a B12 deficiency and cause permanent neurological damage.

Sources: turkey, tuna, liver, whole grains, bananas, potatoes, lentils, chili peppers, beans and molasses.

6. Vitamin K

Benefits: Vitamin K can reduce the risk of arterial calcification and cardiovascular disease. Vitamin K is essential in blood clotting, bone health, and brain and nervous system functioning. Without an adequate amount of vitamin K, the body has a greater risk of atherosclerosis and stroke.

Risks: Vitamin K can actually inhibit antioxidants from doing their job. Too much vitamin K can result in oxidative damage from free radicals. It can also reduce the effect of blood-thinning medications resulting in dangerous blood clots.

Sources: kale, spinach, collard greens, turnip greens, mustard greens, cabbage, broccoli, brussels sprouts, swiss chard and asparagus.

7. Iron

Benefits: Most of the body's iron is located in the hemoglobin. Iron carries oxygen to other parts of the body through these hemoglobin. Iron is essential for proper health and growth. It is necessary for the body to produce red blood cells and regulate body temperature.

Risks: The body has no natural way to get rid of extra iron. Any excess is stored in body tissues like the liver, heart, and pancreas. Severely excessive amounts of Iron can cause liver and heart damage. Symptoms of too much iron are tiredness, constipation, nausea, upset stomach, heart palpitations, and pain in the joints.

Sources: beef, chicken, clams, cod, flounder, oysters, pork, salomon, shrimp, tuna, turkey, almonds, baked beans, black eyed peas and bread.

Numbers based on adults. These amounts will fluctuate if pregnant or lactating.
IU - international units
mg - milligrams

Vitamin / MineralDaily Recommended IntakeUpper Limit

Folic Acid (Vitamin B9)

400 IU

1000 IU

Vitamin A

700 - 900 mg

3,000 mg

Pyridoxine (Vitamin B6)

1.3 mg

100 mg

Niacin (Vitamin B3)

14 - 16 mg

35 mg

Vitamin E

20 IU

1,000 mg

Vitamin D

600 IU

2,000 IU

Vitamin C

75 - 90 mg

2,000 IU

Vitamin K

65 - 80 mg

Not Defined


10 - 15 mg

45 mg


12 - 15 mg

40 mg

8. Zinc

Benefits: Zinc stimulates a ton of enzymes that get different reactions started in our body. Zinc helps maintain a healthy immune system, wound healing, your sense of smell and taste, and DNA synthesis. Zinc is also needed for sperm development, ovulation, and fertilization.

Risks: The most common issues associated with too high of a zinc intake is gastrointestinal problems. Upset stomach, diarrhea, and vomiting are also common symptoms of excess zinc. Often, zinc poisoning can result in hospitalization due to decreased urine output. Heavy metal poisoning is a possibility from excess zinc. This kind of poisoning causes a metallic taste in the mouth, low blood pressure, convulsions, shortness of breath, and shock.

Sources: oysters, beef shanks, Alaskan king crab, pork shoulder, fortified breakfast cereals, chicken leg, pork tenderloin, lobster, baked beans, cashews, cheese, milk and yogurt.


Most people do not need to worry about overdosing on vitamins and minerals through their normal daily meals. Toxic levels are typically only reached when an individual is getting the nutrient from a source other than food or drink.

Unless you have a vitamin deficiency or a medical condition, I would not recommend taking any vitamins or supplements without consulting with your doctor. Often times, if the issue is severe enough, a doctor will tell you which vitamins or minerals to take. If you do not have an extreme case, you can typically increase your intake by simply eating foods that are rich in that vitamin or mineral.


This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.


Megan Garcia (author) from Florida on December 03, 2012:

Your Welcome Abdul. Thank you for reading.

Abdul Wahab from Yanbu Al-Bahar, Al Madinah, Saudi Arabia on December 03, 2012:

oh, i never knew that excess intake of vitamins can have such side effects,

Thanks for sharing the info........

Megan Garcia (author) from Florida on December 02, 2012:

Yes it is.

Sleepylog from Australia on December 02, 2012:

Yes, Vitamin A is a good example.

Megan Garcia (author) from Florida on December 02, 2012:

themsasterofall - I do agree with you that it is not that common, but I want people to know that it is possible.

themsasterofall on December 02, 2012:

The fact is that vitamin overdoses are quite uncommon, but deficiencies are commonplace in our society. Even many fat soluble vitamins are not toxic unless you take ridiculous amounts of them over a period of time. Also, the so called "recommended daily allowances" are only the determined minimal amounts the government has determined you must get every day so that you won't die. Many of them were also established decades ago and as such are grossly inaccurate anyway.

Megan Garcia (author) from Florida on December 02, 2012:

rasta1 - If you will notice, it really takes quite a bit more than the recommended amount to cause damage.

Marvin Parke from Jamaica on December 02, 2012:

The Daily recommended amounts is a nice reference.

Megan Garcia (author) from Florida on December 02, 2012:

What people need to realize that sometimes the side effects of taking to much can be worse than what they are trying to fix.

Sleepylog from Australia on December 02, 2012:

Glad to see such an article because too many people abuse supplements hoping to get faster results, alas it doesn't work that way and it IS possible to have to much of a good thing.