You don’t want to overdose on these 5 vitamins

Put down the pill bottle. 

Turns out, you can get too much of a good thing when it comes to certain vitamins and minerals. And the consequences can be way more serious than an upset stomach. 

“We definitely want people to be cautious with [fat-soluble vitamins] because they will just build up in the system, and those are the ones that can cause more toxicity in excess,” Dr. Wendolyn Gozansky, a geriatrician and chief quality officer with Kaiser Permanente, told AARP.

Vitamins are split into two categories — water-soluble and fat-soluble. Water-soluble vitamins are not easily stored in the body and can be “washed out.” They include vitamin C and B vitamins (like folate, biotin, thiamine, niacin and more), according to the National Institutes of Health (NIH). Fat-soluble vitamins, on the other hand, are more easily stored — which also means they can build up and cause toxicity.

In general, the average healthy person doesn’t need to take extra supplements. But that doesn’t stop people from doing so. For people aged 20 and over, nearly 58% reported taking some type of vitamin or supplement in the last 30 days, according to the Centers for Disease Control and Prevention (CDC). Use was higher among women (63%) than men (51%).

While multi-vitamins are generally fine, and an occasional supplement probably won’t do much harm, some vitamins or minerals taken in excess can wreck havoc on your body. Here’s what to know about each of them.

Calcium

The stuff found in milk does a body good — but only when you take it in appropriate amounts. Calcium is the most abundant mineral found in the body, according to the CDC, but that doesn’t mean you can take it endlessly. About 98% of calcium is stored in the bones, but it’s also important for teeth health, and other vital functions like blood vessel contraction and blood clotting. 

And getting too much — typically from supplements and not from chugging glasses of milk — can do serious harm. Symptoms of an overdose can include abdominal pain, nausea, vomiting and even kidney stones and heart problems, according to AARP. 

“Anything over 2,200 milligrams a day, we start worrying about having stomach upset or potentially predispose people to kidney stones,” Gozansky said.

In general, people need 1,000 – 1,200 mg per day, depending on your age and sex. In addition to milk, other dairy products like yogurt can help you get there.

Iron

Although low iron can cause anemia — which can be a serious condition — most people don’t have that issue. You can get iron from a number of foods, like red meat, fortified cereals, oysters, lentils and spinach. In some cases — like during pregnancy — iron supplementation might be necessary, according to the NIH. But most of the time, you don’t need it. 

Too much iron can have uncomfortable outcomes. Aside from the nausea, vomiting and diarrhea associated with other overdoses, iron can also mess some major organs.

“Too much iron actually can cause problems with the liver and the heart because it will deposit in the tissues,” Gozansky said.

The CDC recommends 8 – 18 mg per day, depending on your age and sex.

Vitamin A

You might be familiar with the cosmetic form of vitamin A — a.k.a. retinol — but the vitamin itself is responsible for a lot more than just fighting wrinkles and aging skin. 

Vitamin A is another fat-soluble vitamin that can build up toxicity in the liver when you take too much of it. 

“You can have some acute symptoms like nausea, vomiting, vertigo, blurry vision,” Dr. Matthew Farrell, family medicine physician at the Ohio State University Wexner Medical Center, told AARP. Other symptoms could include severe headache and muscle or coordination problems. Eventually, an overdose of vitamin A can lead to coma or even death — though most people recover with proper intervention.

Vitamin D

Often called the “sunshine vitamin,” Vitamin D is unique because although we can get it from food, your body makes vitamin D from sun exposure. It’s also one of the most common types of supplements taken, according to the CDC. 

Getting enough vitamin D is essential for your bones, kidney function and muscle health — but too much can cause serious problems. 

“We don’t want people getting too much vitamin D because that can actually cause problems as well with high calcium levels in the blood,” Gozansky explained. 

In one case study from 2022, a British man began taking 150,000 IUs of vitamin D on the advice of a nutritionist — that’s 375 times the daily recommended amount. For months, the man experienced nausea, vomiting, dry mouth, diarrhea, and weight loss. By the time he finally showed up at the hospital, his kidneys were failing. In another similar case, an 89-year-old man died from hypercalcemia — meaning he had way too much calcium in his blood — due to overdosing on vitamin D. 

At the time, the coroner even noted in his report: “In my opinion there is a risk that future deaths will occur unless action is taken.” 

For the average person, 600 – 800 IUs of vitamin D are all you need daily. The CDC says you can get this with just 5 – 30 minutes of sunshine exposure daily. It’s also found in fatty fish, such as salmon, tuna, trout; plus dairy like egg yolks and cheese. Several cereals are also fortified with vitamin D.

Vitamin B6

Despite the fact that vitamin B6 is one of the few wat-er-soluble vitamins on this list — meaning it’s really tough to overdose from food sources alone — it can still be dangerous when you take too much. Taking more than 250 mg per day can cause nerve damage and pain, reports AARP. 

Eating foods like chickpeas, liver, tuna and salmon will do the trick instead, you only need 1.3 – 1.7 mg per day, depending on your age.