Doctors have raised the alarm about the risks of a handful of supplements that could be hiding in your medicine cabinet.
Vitamin A, vitamin B3, also known as niacin, and vitamin E can be dangerous in high amounts, causing nausea, bone pain, and even internal bleeding.
A balanced diet contains all of these nutrients in small amounts. Vitamin A is found in leafy green vegetables, milk, and eggs, vitamin B3 is found primarily in red meat, and vitamin E is abundant in seeds, nuts, and fruits and vegetables.
However, experts have warned that some supplement products contain high amounts of these nutrients, meaning it could be easier than you think to overdose.
Certain supplements can have unpleasant and potentially dangerous side effects, such as thinning the blood, which has been linked to an increased risk of bleeding.
In a report for Discoverco-authored by Dr. Ahmad Talha Azam, a Texas-based internal medicine physician, the three vitamins above stand out as potentially harmful due to the risk of taking too many.
‘Some people take them [vitamins and supplements] because they automatically assume that vitamins and supplements have only positive health benefits, but very little is known about how they actually work,” said Elena Goun, a chemistry professor at the University of Missouri who studies supplements.
Niacin, or vitamin B3, is a popular supplement recommended for high cholesterol, arthritis, and brain function.
The recommended daily amount of niacin is 16 mg for men, 14 mg for women, and 18 mg for pregnant women.
Niacin used to be recommended for people at risk of developing heart disease, according to Harvard TH Chan School of Public Health.
but a series of studies found that niacin did not actually reduce the risk of developing heart disease, stroke, or increase longevity, but was associated with negative side effects such as diarrhea and skin redness.
Other forms of vitamin B3, such as the popular anti-aging supplement nicotinamide riboside, have been linked to an increased risk of brain cancer.
According to Harvard, taking more than 35 milligrams (mg) per day increases the chance of experiencing harmful effects, especially if taken over a long period of time. Some side effects may include itching, redness of the skin, dizziness, nausea, upset stomach, or fatigue.
Supplement package available online as well as 50 mg in a daily dose.
Symptoms of a niacin overdose include dizziness, nausea, and fatigue.
Vitamin A is a recommended supplement for eye health and to support the immune system.
The FDA recommends about 900 micrograms of vitamin A per day for men and 700 micrograms for women. If you take more than 3,000 micrograms a day, you could be at risk for toxicity.
DailyMail.com found some products containing up to 7,500 micrograms in one pill.
“Vitamin A toxicity may be more common in the US than a deficiency, due to the high doses of preformed vitamin A (retinol) found in some supplements,” according to the Harvard TH Chan School of Public Health.
If you take too much vitamin A, you may develop bone pain, nausea, vomiting, dry skin, blurred vision, and sensitivity to bright light.
In the long term, researchers have also linked intake of vitamin A and similar forms, such as beta-carotene, to an increased risk of lung cancer– especially if you previously smoked.
Many types of supplements contain much more than the recommended daily intake, experts say, which could increase the risk of taking too many nutrients.
Vitamin E is a supplement that has been recommended for its immune-boosting effects. It is found naturally in nuts such as peanuts and almonds, seeds and some fruits such as mango and kiwi.
The NIH recommends Adult men and women take 15 mg of vitamin E daily, either through diet or a supplement.
If you take more than 1,000 milligrams of the nutrient, you could be at risk of developing vitamin E toxicity, which manifests itself in muscle weakness, diarrhea, and nausea.
The most common risk of taking vitamin E is the fact that it acts a bit like a blood thinner. according to Merck. Therefore, if you are injured while taking this medication, you may bleed, internally or externally, much more than you would naturally.
If you take too much vitamin E, you could be at higher risk of internal bleeding or you could simply experience some unpleasant side effects, such as diarrhea.
In rare cases, the NIH reports that vitamin E has caused life-threatening bleeding, even worsening the consequences of strokes. A study from Harvard Medical School reported that taking vitamin E increased the chance of developing a bleed by 22 percent.
Aside from those three particularly dangerous supplements, there are other things to consider in this area, such as multivitamins.
These products may contain “substantially higher amounts of some vitamins and minerals” than the recommended daily allowance, and may even reach dangerous levels, according to the NIH.
There are also some supplements that interact with prescription medications.
For example, taking the herbal supplement St. John’s Wort can cause ineffective contraceptive. That’s why experts recommend talking to your doctor before starting a new supplement regimen.
With all this in mind, whenever possible, dietitians recommend getting nutrients from a well-balanced diet.