Today we’re going to talk about something that’s becoming really important for anyone taking medications like Ozempic, Wegovy, or other GLP‑1 receptor agonists. You probably already know the benefits of GLP-1s—smaller appetite, better blood sugar control, and noticeable weight loss. But here’s the catch: eating less can sometimes mean you’re also taking in fewer essential vitamins and minerals that your body needs.
In this episode, we’re going to explore how to make sure every bite counts and when it might make sense to consider supplements.
Which Nutrient Deficiencies Can Happen And Why
GLP‑1 receptor agonists don’t directly cause vitamin or mineral deficiencies, but the effects of the medication on your appetite and digestion can indirectly make deficiencies more likely.
Let me try to explain.
When your appetite drops and you’re eating smaller meals, you’re naturally getting fewer nutrients. Less protein, fewer vegetables, less fruit, and sometimes lower fat intake all mean fewer vitamins and minerals.
Furthermore, if you experience side effects like nausea, vomiting, or diarrhea, that can make nutrient absorption even more challenging. So it’s really a combination of reduced intake, less variety, and, in some cases, stomach upset that can create nutrient gaps over time.
Let’s talk about the nutrients that tend to be most affected and why.
Let’s start with vitamin B12. A small study found that people taking semaglutide after weight-loss surgery had lower B12 levels, though it’s not yet clear if the same effect happens in people who haven’t had surgery. Still, low B12 is already common in those with obesity or Type 2 diabetes—the very conditions GLP-1 medications are meant to treat.
Vitamin B12 is crucial for energy, red blood cell production, and nerve health. Because it’s mainly found in animal products like meat, poultry, and dairy, eating smaller portions or skipping protein-rich foods can make it easier to fall short.
If your levels are low, B12 is available both over the counter and by prescription, and your healthcare provider can help determine which form and dose are best for you.
Iron is another nutrient that can be impacted. With smaller meals or less variety, especially fewer meats (e.g., red meat and dark poultry) or iron-fortified foods (e.g., breads and pastas), iron intake can decline, which could eventually lead to fatigue or anemia.
If you’re taking a GLP‑1 medication and feeling extremely fatigued, it’s a good idea to ask your healthcare provider to check your iron levels. They can see if you’re getting enough from your diet and, if needed, suggest an over-the-counter or prescription iron supplement. Just don’t start taking extra iron on your own—too much can be harmful.
Fiber is also a common one that gets overlooked. Smaller meals often mean fewer fruits, vegetables, and whole grains. Fiber is importanat for gut health, blood sugar control, and satiety, so it’s important to make sure the foods you are eating have fiber, or consider a supplement like psyllium (Metamucil) if needed.
Vitamin D is another nutrient to keep an eye on. About a quarter of people have low levels, which can happen if you don’t get enough sunlight, follow a vegan diet, are over 40, or have darker skin. Smaller meals or limited intake of fatty fish like salmon or sardines, egg yolks, and fortified foods such as orange juice and breakfast cereals can make it even harder to get enough. People with obesity or diabetes are also more likely to have lower vitamin D levels.
Vitamin D isn’t just important for strong bones—it also helps reduce inflammation, supports your immune system, and plays a role in blood sugar regulation. If needed, it’s available both as an over-the-counter supplement and by prescription, and your healthcare provider can help determine what’s best for you.
Zinc, too, is often overlooked, but it’s key for immune function, metabolism, and even taste. Since zinc is found in foods like meat, nuts, and seeds, reduced intake can put you at risk of deficiency.
Moving along. The next one I want to talk about is folic acid, or folate, which is critical for red blood cell production, DNA synthesis, and heart health. If your meals are smaller or less varied, it’s easy to fall short on foods that affect folic acid levels like leafy greens, legumes, and fortified grains.
Fat-soluble vitamins, such as vitamins A and E, also need attention. If you’re eating very low-fat meals, which sometimes happens when people try to minimize GI side effects, absorption of these vitamins can be impaired. Try focusing on incorporating healthy fats like olive oil, avocado, nuts, or fatty fish—small amounts go a long way.
Lastly, I want to briefly mention magnesium and potassium to round out the list. They’re essential for muscle, nerve, and heart function, and losses can occur if stomach-related side effects like nausea and diarrhea are present or if intake of nuts, whole grains, and leafy greens is reduced.
So when you add it all up, someone taking a GLP‑1 medication can be at risk for gaps in a broad range of nutrients—not because of the drug itself, but because of reduced food intake, changes in nutrition composition, and potential stomach-related side effects.
A Practical Framework for Supplementation
So, how do you know if you actually need supplements? A good place to start is a baseline assessment. This might include lab checks for things like B12, iron, and vitamin D. That said, not everyone has easy access to labs, and testing can get expensive.
That’s why taking a close look at your diet is just as important. Your healthcare provider can help assess what you’re actually eating—whether you’re skipping meals, sticking to the same foods, or avoiding fats entirely. The goal is to meet your nutrient needs through whole foods as much as possible.
If your labs or dietary review show gaps, then targeted supplements may be appropriate—but it’s important not to take everything “just in case.” Too much of certain vitamins or minerals can be harmful, and supplements can get pricey, so there’s no need to spend money unnecessarily.
Finally, keep the conversation open with your healthcare provider and pay attention to any symptoms like fatigue, muscle cramps, or hair loss, since these can be early hints that something is off.
Thanks for listening to The Peptide Podcast.
Until next time, be well, and have a happy, healthy week.
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