In the United States, deficiencies in vitamin D and iron are alarmingly common, with one in four Americans lacking sufficient vitamin D and approximately 10 million people suffering from iron deficiency. As a result, many turn to supplements to meet their nutritional needs, particularly during the winter months when sunlight—our primary source of vitamin D—is scarce. Additionally, individuals following a vegan or plant-based diet often rely on iron supplements to compensate for the absence of meat in their diet.
While these nutrients are essential for overall health, leading gastroenterologists caution that their consumption in supplement form can lead to side effects that should not be overlooked. These side effects not only cause discomfort but may also interfere with the body’s ability to absorb and utilize these vital nutrients.
The Risks Associated with Iron Supplements
Dr. Geetanjali A. Akerkar, a board-certified gastroenterologist with Gastro Health in Chelmsford, Massachusetts, highlights the critical role iron plays in creating red blood cells. Since the body cannot produce iron on its own, it must be obtained through iron-rich foods or supplements.
Dr. Augustine Tawadros, another board-certified gastroenterologist with Middlesex Monmouth Gastroenterology, underscores iron’s importance for gut health. “Iron is a fundamental nutrient for the growth of beneficial bacteria in your gut, which helps maintain a healthy balance against pathogenic bacteria,” he explains. He adds that iron is vital for maintaining the gut barrier, which ensures proper gastrointestinal function.
However, Dr. Akerkar and Dr. Tawadros warn that iron supplements can cause gastrointestinal issues, with constipation being the most common side effect. Dr. Asma Khapra, a board-certified gastroenterologist with Gastro Health, notes that other potential side effects include an upset stomach, nausea, vomiting, and even dark stools. Dr. Tawadros emphasizes the importance of consulting a gastroenterologist if you notice dark stools, as this could indicate gastrointestinal bleeding rather than just a side effect of the supplement.
To mitigate these side effects, Dr. Tawadros recommends taking a fiber supplement or stool softener (but not simultaneously with iron supplements). He also suggests consuming iron supplements with food if stomach cramps or nausea occur, despite iron being best absorbed on an empty stomach. Increasing hydration can also help alleviate some of these gastrointestinal issues.
The Impact of Vitamin D Supplements
Vitamin D is equally crucial for both overall health and gut health. “Like iron, vitamin D is essential for the gut microbiome, helping to preserve beneficial bacteria and maintain the integrity of the gut barrier,” Dr. Tawadros says. Dr. Khapra adds that some studies have even linked vitamin D with the prevention and management of colon cancer.
Although vitamin D supplements are generally well-tolerated, Dr. Akerkar points out that taking them on an empty stomach can sometimes lead to an upset stomach. To avoid this, she advises taking vitamin D supplements with food.
There is also the risk of vitamin D toxicity if taken in excess, especially if combined with other supplements containing vitamin D, such as multivitamins. Symptoms of excessive vitamin D intake include loss of appetite, nausea, and dehydration. To ensure you are not getting too much or too little vitamin D, Dr. Tawadros recommends having your vitamin D levels checked through a blood test by your healthcare provider.
Conclusion
While supplements can help bridge nutritional gaps, experts agree that it is best to obtain nutrients through a varied diet and regular exposure to sunlight for natural vitamin D. If you experience any side effects from supplements, it’s essential to consult with your healthcare provider to address them. This approach ensures that your body absorbs and uses these critical nutrients effectively, allowing you to feel your best.