Gastroenterologists Are Begging People to Pay Attention to the Side Effects of These 2 Common Vitamins
09/16/2024
Vitamin D and iron are two nutrients that many people in the U.S. don’t get enough of. One in four people in the U.S. don’t get enough vitamin D while 10 million people in the U.S. are deficient in iron.
Since sunlight is the primary way to get enough vitamin D, it’s common for many people to take a vitamin D supplement during the winter to ensure they’re getting enough. And if you are vegan or primarily eat a plant-based diet, you may be taking an iron supplement since it can be trickier to get enough of the nutrient if you don’t eat meat.
Both nutrients are crucial for overall health, but as gastroenterologists explain here, consuming them in supplement form can have some side effects it’s important to pay attention to. Not only can these side effects be bothersome, but they could also get in the way of your body absorbing and actually using the nutrients. Keep reading for everything you need to know.
What Gastroenterologists Want Everyone Taking an Iron Supplement To Know
Dr. Geetanjali A. Akerkar, MD, a board-certified gastroenterologist with Gastro Health in Chelmsford, Massachusetts, explains that iron is important for many reasons, chief among them creating red blood cells. She explains that since the body cannot make iron, it must be consumed through iron-rich foods or in supplement form.
Dr. Augustine Tawadros, MD,a board-certified gastroenterologist with Middlesex Monmouth Gastroenterology, a division of Allied Digestive Health, explains that iron is an important nutrient for gut health. “It is a fundamental nutrient for the growth of many beneficial bacteria in your gut. Your gut requires a healthy balance of these beneficial bacteria to overcome the pathogenic bacteria in your body and prevent gastrointestinal infections. It is also vital to maintaining the gut barrier and ensuring proper functioning of your gut,” he says.
This means that not getting enough iron means the gut can’t function as well as it should. “In the gut, most bacteria depend on iron to survive as well,” says Dr. Asma Khapra, MD, a board-certified gastroenterologist with Gastro Health.
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With all this in mind, you may be ready to start taking an iron supplement, but before you do, all three G.I. docs say it’s important to be aware of the side effects. “G.I. side effects are the most common issues with iron supplements—the biggest one being constipation. Some formulations may be a bit gentler on the gut, but it can be person specific and you may need to try out a few different types to find a well-tolerated supplement. Other G.I. side effects include an upset stomach, nausea or vomiting,” Dr. Khapra says.
Dr. Tawadros says that stomach cramps and constipation can also be side effects of taking an iron supplement. He says that it can cause stools to look dark as well. “In regards to dark stool, I recommend consulting a gastroenterologist if it occurs, because dark stool may also be a sign of gastrointestinal bleeding and will need further evaluation before it can be safely attributed to a side effect of iron supplementation,” he says.
If an iron supplement is making you constipated, Dr. Tawadros recommends taking a fiber supplement or stool softener, though not at the same time as your iron supplement. “Although iron is best absorbed on an empty stomach, you can try taking it with food if you start having stomach cramps or nausea with vomiting,” he says. Both Dr. Tawadros and Dr. Khapra say that upping your hydration can also help minimize the side effects of taking an iron supplement.
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What Gastroenterologists Want Everyone Taking a Vitamin D Supplement To Know
Vitamin D is another nutrient that is important for overall health and, specifically, gut health. “Similarly to iron, vitamin D is essential to the gut microbiome. It helps preserve the beneficial bacteria in your gut and prevent the proliferation of pathogenic bacteria. Also, vitamin D helps maintain the integrity of the gut barrier, which is a major function of the immune system to protect against gastrointestinal infections,” Dr. Tawadros says. Dr. Khapra adds to this, saying that some scientific research shows a connection between vitamin D and colon cancer prevention and management.
While all three doctors say that vitamin D supplements tend to be well-tolerated by most people, they say that it is possible to experience an upset stomach as a side effect, something that Dr. Akerkar says it is more likely to happen if it’s taken on an empty stomach. For this reason, she suggests taking a vitamin D supplement with food if it’s causing any stomach troubles.
There is also a risk of getting too much vitamin D—such as if you are taking a vitamin D supplement in addition to vitamin D being in other supplements you may be taking, like a multivitamin. When this happens, Dr. Tawadros says it’s possible to experience loss of appetite, nausea, dehydration and dehydration. To know what your vitamin D levels are—including if you are getting too little or too much of the nutrient—you can ask your healthcare provider for a blood test to check.
Ideally, it’s best to eat a varied diet to get the nutrients the body needs through food—and to spend some time each day in direct sunlight for your daily dose of vitamin D. Supplements are just there to fill in the gaps. If you are experiencing any side effects at all, talk with your healthcare provider about how to mitigate them. That way, not only will you physically feel your best, but you can be sure that your body is absorbing and using these crucial nutrients.
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