Supplement Overload: Can You Overdose on Vitamins?

Our hectic lifestyles can make it hard to eat well. Some people turn to vitamins, minerals, and other supplements to help pick up the slack. Supplements are supposed to give us more of what we need—but can you get too much of a good thing?

Although their prevalence may make them seem benign, some vitamins and minerals can be harmful if we overdo them, with excess levels leading to toxicity.

Let’s look at four common vitamins and minerals, why we need them, and signs that you may be getting too much.

Vitamins and Minerals

Vitamins can be either water-soluble or fat-soluble. Water-soluble vitamins include C and B vitamins (niacin, folate, thiamine, riboflavin, biotin, pantothenic acid, B6, and B12). Water-soluble vitamins are not stored in the body and are excreted via urine.

Fat-soluble vitamins, however, are stored in the body’s tissues, which means we can take too much, and in excess amounts, they can lead to toxicity. The four fat-soluble vitamins are A, D, E, and K.

Calcium and iron are essential minerals to maintain health, but too much of either can lead to serious side effects as well.

Renee Kindler is a functional medicine and nurse practitioner at Aonani Functional Medicine. When it comes to vitamins, minerals, and hormones, she told The Epoch Times it’s best to follow “the Goldilocks principle.”

“You don’t want too much or too little. Some vitamins and minerals, your body is good at eliminating extra if you have extra, and for some of them, it’s more of a challenge,” she said.

Vitamin A

Vitamin A, also known as retinol, is a fat-soluble vitamin needed for clear vision, a healthy immune system, and growth, development, and reproduction.

The recommended daily allowance, or RDA, of vitamin A we need depends on our age and gender and is measured in micrograms (mcg) of retinol activity equivalents, or RAE.

Note: Recommended daily allowances are often based on the minimum amounts needed to avoid deficiency and disease and not necessarily levels required for optimal health.

“Vitamin A can cause birth defects, and you can’t reverse that. If somebody’s taking it for acne, a lot of times that can be a childbearing age woman. So that’s something to pay attention to,” Mrs. Kindler says.

Excessive beta-carotene intake can make the skin turn orange, However, this is harmless and can be remedied by taking less.

The NIH states that the upper limit (UL) for vitamin A from all sources is 3000 mcg for adults over 19 years. There are no upper limits for beta-carotene and other forms of provitamin A.

The authors cautioned that because preformed vitamin A is being added to many processed foods, there was an urgent need to develop population biomarkers to diagnose hypervitaminosis before toxicity.

Vitamin A can interact with certain medications. Conversely, some medications can affect the absorption of vitamin A, so speak to your prescribing physician if you are on medications and considering taking a vitamin A supplement.

Vitamin D

Vitamin D, or calciferol, is an essential nutrient we get from the foods we eat and a hormone our bodies produce. The two types of vitamin D vital to human health are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).

Vitamin D2 primarily comes from plants, while our vitamin D3 comes from animal sources (about 10 percent), with the rest produced by our bodies from exposure to sunlight. Vitamin D3 is better absorbed and more potent than vitamin D2. The liver and kidneys must convert all the vitamin D2 and D3 we get from foods or supplements into the active form our bodies can use.

Vitamin D is fat-soluble and necessary for our bodies’ absorption of calcium and phosphorus, which are needed to make bones. Without calcium and vitamin D, we are more susceptible to osteoporosis, where bones become weak and are more likely to break.

Dairy foods, green vegetables, fish, beans, nuts, and fruits are rich in calcium. Some foods are also fortified with calcium to help us achieve optimal levels.

Exercise, vitamins D and K, magnesium, and phosphorus help the body absorb calcium and increase bone mass. Other factors that affect calcium absorption include age, diseases (like Crohn’s and celiac), and medications.

Many forms of calcium are available in supplement form, and they differ according to their content, how well they are absorbed, and their cost. The two most common are calcium citrate and calcium carbonate.