Should I Be Taking Supplements?

by Katy Keogh, MS, RDN, LD

Last Updated: September 29, 2020

Since the Coronavirus began, an interest in foods and supplements to support immune health have become as hot of a topic as the pandemic itself. Trends for supplement use have skyrocketed like never before. As dietitians, we have certainly seen our patients’ interest peak as well. People tend to lean on a supplement as an easy way to boost their immune system and help ward off COVID-19. However, there are many misconceptions about supplements. Here are three things to consider when taking supplements.
  1. More is not always better.
    If you have a somewhat balanced diet and don’t have a deficiency, then taking more than what you need of a nutrient via supplement form is typically not beneficial. It is important to obtain as many nutrients as possible from food and to have a balanced lifestyle for your immune system to run at 100%. Once our bodies reach their capacity on certain nutrients, their tanks are full, thus having extra nutrients won’t make your immune system run above 100%.
  2. You could do more harm than good.
    Supplements are regulated in a reactive way, rather than a proactive way. This means that they are regulated to ensure that they aren’t harmful, but there are supplement types or dosages that could have a negative effect in certain people. Contraindications could occur for people with certain medical conditions, if the supplement harmfully interacts with a medication, or if the dosage is too high.
  3. The “expensive pee” effect.
    What our body doesn’t need or use is generally excreted in urine and stool. There are many supplements that have not been shown to be effective in research, increasing the likelihood that these may be excreted as waste if not needed. Most people don’t realize that while supplements are regulated against false claims and doing harm, manufacturers can sell supplements that may not be effective. This is not to say that all supplements are ineffective, but it varies on an individual basis.

Here are the three supplements that we find most people misusing and therefore are often recommended to discontinue.
  1. Probiotics
    According to a recent Healio article, “In newly issued guidelines, the American Gastroenterological Association did not recommend using probiotics for most digestive conditions.” We know that probiotics have been shown to be helpful for some digestive and other medical conditions, but there is some evidence that using probiotics for general use, in people with certain medical conditions or for conditions that lack research support, could cause harm. Anytime you introduce bacteria to the gut, the microbiome is altered. One theory is that your gut microbiome is a unique, inter- and intra-functioning system designed just for you. If you alter that, then you risk altering the optimum functioning of your entire system. It is unknown, but also unlikely, that taking a probiotic would improve the immune system of a generally healthy person. Probiotics should only be taken by persons that have conditions for which research supports usage, and the exact probiotic dosage, strain, and brand should be precisely prescribed to fit that circumstance. If other aspects of wellness (managing stress, sleep, and eating enough prebiotic foods) are not maintained, the probiotics will not have their full effect.
  2. Vitamin C
    While vitamin C is essential for the immune system, most people get sufficient vitamin C if their diet includes some intake of fruits, vegetables, or fortified foods. The average adult needs 75mg (women) to 90mg (men) per day. If you are a fruit and veggie fanatic, or enjoy the vitamin-type waters or juices, you likely get more than the daily recommended amount. Some research shows that higher amounts may benefit the immune system, but those benefits are typically seen with vitamin C through foods, not supplements. Excess vitamin C can cause diarrhea, nausea, and stomach cramps and can be damaging for people with a condition called hemochromatosis. We have personally seen many people with “stomach issues” get some resolution after ditching their excessive vitamin C supplement. The upper limit recommendation for vitamin C is 2,000mg per day for adults.
  3. Zinc
    Zinc is another top immune system nutrient. It's found in a wide variety of foods, and therefore it is relatively easy to get the recommended 8mg (women) to 11mg (men) per day. Excess zinc can lead to nausea, vomiting, loss of appetite, stomach cramps, diarrhea, and headaches. Be cautious around supplementing with excess Zinc long term, as it can cause a copper deficiency. A copper deficiency can lead to neurological problems and lowered immunity. People often take Zinc to strengthen their immune system without understanding that too much can actually lower their immune system.

Do your research.
While supplements are not medicine, they are like medicine in the regard that they should also be taken in a prescriptive fashion. Before you decide to supplement, check with a registered dietitian and/or doctor to help you figure out what supplements and dosages are right for you. A medical professional can do a full medical and nutritional assessment to help you understand what choices may be right for you, and what supplements have shown promise in research. For your own research, we recommend checking out the National Institutes of Health, Office of Dietary Supplements database for reputable summaries of the effectiveness and risks of many popular supplements. Also, a good mantra to keep in mind is that supplements “are intended to be used as supplements to, not substitutes for, a well-balanced diet and a healthy lifestyle” (Council for Responsible Nutrition).

Disclaimer: This information is educational only and not providing healthcare recommendations. Please see a healthcare provider.


Katy Keogh, MS, RDN, LD

Katy Keogh, MS, RDN, LD

A mom of 2 little kiddos and over 15 years’ experience in nutrition, Katy enjoys helping her patients squeeze good nutrition and activity into an already “full” life and find their own balance with nutrition and health while still enjoying food to the fullest. She is an expert in weight management, mindful eating, digestive health, anti-inflammatory nutrition, culinary nutrition, cooking/baking, and any other topic related to food! Outside of work, you’ll find her traveling, walking, jogging, beer tasting, and eating gelato.