Understanding Supplements: What You Need to Know

In the United States, there are over 100,000 dietary supplements available—ranging from capsules and powders to gummies—claiming to enhance or maintain our health. These products can be composed of vitamins, minerals, botanicals, and amino acids, sometimes alone and other times in various combinations.

Despite the rising popularity of these supplements, there’s a common belief that they are completely safe. However, Dr. Pieter Cohen, an internist and associate professor at Harvard Medical School, warns that taking too much of certain nutrients can lead to adverse effects. It’s crucial to understand proper dosages and ensure the quality of what you’re consuming.

Here’s some advice from experts on how to navigate the supplement landscape, including the risks of excessive intake.

Be Mindful of Your Supplement Choices

Ideally, we should obtain our necessary nutrients from our diet, according to Dr. Denise Millstine, director of integrative medicine at the Mayo Clinic Arizona. Unfortunately, this isn’t always feasible; factors like limited access to healthy foods or side effects from medications can complicate things.

“There are circumstances where some may require a supplement, while others should be cautious to not overdo it,” mentions Joan Blake, a registered dietitian and clinical instructor at Boston University. “It really varies.”

With such a plethora of products and varying labeling, it can feel overwhelming for consumers trying to find the right supplement—almost dizzying, as Millstine describes.

For various nutrients, there’s something called a recommended dietary allowance (RDA), indicating how much one should ideally take daily. This can shift depending on factors like sex, age, and health status. Alongside the RDA, there’s also a tolerable upper intake level (UL), which represents the maximum amount considered safe. Exceeding this can lead to health issues, depending on the nutrient in question.

Furthermore, in the U.S., there’s limited pre-market regulation of supplements. Dr. Cohen explains that the contents and quantities listed on labels often lack accuracy, as the FDA does not pre-approve supplements. To verify label accuracy, it’s wise to look for certifications from organizations like the National Sanitation Foundation (NSF) or the United States Pharmacopeia (USP).

Consult Your Doctor Before Taking New Supplements

Since recommended dosages can vary from person to person, discussing your supplement plans with a healthcare provider is essential. They can help determine any interactions with existing medications or supplements, as Dr. Cohen highlights. Potentially harmful effects might arise, or certain medications could lose their effectiveness.

Supplements might even skew blood tests, leading to false results, warns Dr. Fernando Carnavali, an associate professor at the Icahn School of Medicine at Mount Sinai. It’s vital to maintain an open dialogue about your vitamin and supplement use with your physician to stay informed about any new research regarding interactions and effects.

Using supplements cautiously, akin to taking over-the-counter medications such as Tylenol, is advisable, according to Millstine. Sticking to recommended doses is also wise. The National Center for Complementary and Integrative Health website is a good resource for dosage information. Additionally, the U.S. Department of Agriculture offers a tool for calculating vitamin and mineral needs.

And, as Millstine adds, avoid taking dosing advice from product sellers, since there’s a possibility of bias involved.

Carnavali also mentions that due to the perception of vitamins and minerals as “natural,” patients might hesitate to disclose their supplement usage to their healthcare providers. It’s not uncommon for patients to seek medical advice only to find that their vitamin or supplement habits were contributing to their symptoms. “We’re not here to judge,” he reassures, “we’re here to guide you.”

What Happens if You Overdo It?

Multivitamins: These usually contain several vitamins and at least one mineral. However, there are no universal standards on what nutrients must be included or their amounts. According to the National Institutes of Health, some multivitamins may exceed established ULs. Therefore, the risk of overconsumption is significant, especially if taken alongside other supplements.

What kind of harm might result? That varies based on the specific nutrient involved. “Multivitamins can be complicated since you have to consider each component, and there are so many,” comments Millstine.

There are specific risks for different individuals. For instance, the NIH advises that smokers and those who’ve quit might want to steer clear of multivitamins with high amounts of beta-carotene or vitamin A, which could elevate lung cancer risk in smokers. Pregnant individuals should also limit vitamin A intake to avoid birth defect risks.

Those on blood thinners should consult their doctor before using multivitamins containing vitamin K, as it may diminish the effectiveness of those medications.

Vitamin D: “Vitamin D can become quite harmful when consumed excessively,” cautions Millstine. High intake can lead to symptoms like nausea, excessive urination, and in severe cases, issues like kidney failure or irregular heartbeats. The NIH states that high levels of vitamin D are “almost always” due to excessive supplementation.

Individual needs for Vitamin D can vary, with the NIH recommending an RDA of about 15mcg, or 600 International Units (IU), for adults between 19 and 70 years old. The upper limit is around 100mcg, or 4,000 IU.

It’s generally recommended to start at a standard dose of vitamin D if advised by your healthcare provider and then reassess levels after three months, according to Millstine.

Omega-3 Fatty Acids: These are found in foods like fatty fish and chia seeds. Supplements such as fish oil or fish liver oil contain two main types: DHA and EPA. Experts haven’t set standardized recommended amounts for these but the FDA suggests keeping combined intake from supplements under 5 grams daily. Exceeding that can heighten risks for bleeding and stroke, according to the Mayo Clinic.

Low-quality omega-3 supplements can increase side effects like heartburn and nausea. Millstine advises checking what else is in the product, as additional components might lead to gastrointestinal issues and higher bruising risk.

Another omega-3 fatty acid, alpha-linolenic acid (ALA), comes from plants. You can find ALA in flaxseed oil supplements. Recommended amounts for adults range from 1.1 grams to 1.6 grams.

Calcium: The usual daily recommendation for adults is between 1,000mg and 1,200mg, ideally split into no more than about 500mg portions at once, as noted by Millstine. The upper limit varies depending on age and health status. High calcium intake can negatively interact with other supplements and medications.

Consuming too much supplemental calcium might lead to kidney stones. Research indicates mixed results surrounding its impact on heart disease, particularly in postmenopausal women. Additionally, the National Health Service highlights that exceeding 1,500mg daily can result in stomach pain and diarrhea.

Vitamin C: Many people overuse vitamin C, trying to ward off illnesses, as Blake explains. While it may slightly reduce the duration of a cold, studies indicate it won’t prevent one altogether.

Any excess vitamin C is expelled through urination. However, chronic overuse can lead to digestive problems like nausea and diarrhea, as Blake notes. Doses exceeding 2,000mg can provoke stomach issues and even kidney stones.

Millstine suggests a daily intake of around 500mg to 1,000mg. “The trouble with taking too much is that it’s not really beneficial, so why put extra strain on your kidneys?” she inquires.

Vitamin B12: The NIH recommends 2.4mcg per day for most adults, although personalized needs can differ. B12 is available in various supplements, many of which contain significantly high dosages.

While rare, taking excessive B12 can result in symptoms like anxiety and headaches, according to Millstine. It may interfere with medications like gastric acid inhibitors and metformin. Other types of B vitamins, such as B6, can be more toxic.

Magnesium: This mineral comes in different forms, including magnesium oxide, citrate, and chloride, each with varying effects. For instance, magnesium citrate is often used as a laxative, which can pose issues for those with sensitive stomachs.

The general recommendation for adults hovers between 300mg to 400mg, varying by age and sex. The UL for supplements is set at 350mg.

There’s typically no risk associated with magnesium in food, but high supplement doses can lead to symptoms like nausea and cramping. In extreme cases, they could even be fatal. Those with kidney disease need to be particularly cautious, as they can’t effectively excrete excess magnesium.

Probiotics: There’s no official

While excessive probiotic intake may not be toxic, it can have other consequences.

“Probiotics might hinder your ability to return to a healthy gut microbiome,” warns Millstine. Overdoing it can compromise the diversity of your gut bacteria. “It’s worth considering carefully whether you really need probiotics.”

Creatine: This supplement can lead to bloating and gastrointestinal discomfort. Millstine suggests a daily intake of 4 to 5 grams.

Research indicates that higher doses of creatine do not providekidney disease should discuss it with their doctor first.

Collagen Peptides: These smaller molecules of collagen can be found in powder or pill forms. Some studies suggest that they could support joint and skin health, but much more research is necessary to validate those claims, according to Carnavali.

Although there’s no standardized dosage, some evidence

Millstine cautions against using collagen peptides in place of a complete protein powder, as they lack essential amino acids necessary for overall health.