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GLP Medications and the Return of “Old” Deficiency Diseases: A Growing Concern


For decades, the United States has largely viewed classic nutrient deficiency diseases, like scurvy and beriberi, as relics of another era. They were conditions we associated with maritime history, extreme poverty, or severe malabsorption, not modern medical weight loss therapy. Yet recent headlines suggesting possible cases of scurvy among people taking GLP-1 medications have forced an uncomfortable question into the spotlight – are we witnessing the return of preventable nutrient deficiency diseases in the context of one of the most widely prescribed drug classes in the country?


At this stage, reported cases of scurvy in GLP-1 users are anecdotal. But the broader signal measurable declines in protein and micronutrient intake among GLP-1 users along with rising rates of diagnosed nutritional deficiencies, is supported by emerging research. And with nutritional deficiencies comes an increased risk of morbidity and mortality. Medicare beneficiaries with diagnosed malnutrition had a 69% increased risk of death and significantly greater annual healthcare costs compared to their well-nourished counterparts (Butsch et al, 2025). Given how widely these medications are being prescribed, the potential long-term health impact of untreated nutrient deficiencies deserves urgent attention.


What Are GLP-1 Medications and Why Are They So Popular?


GLP-1 receptor agonists (GLP-1RAs) are medications originally approved in 2005 to treat type 2 diabetes. In 2021, Wegovy was approved for weight loss, and the celebrity success stories shared on social media that followed caused a surge in popularity that resulted in shortages of GLP-1 medications. Manufacturers responded by increasing production of GLP-1 medications, which are now widely prescribed for weight loss.


As described by Bozick et al (2025), GLP-1RA drugs “work by imitating glucagon-like peptide-1 (GLP-1), a growth hormone that triggers insulin release, reduces blood sugar levels, slows the progress of food along the intestinal tract, and stimulates parts of the brain that control craving and satiety.”


By reducing appetite and slowing digestion, GLP-1 medications can significantly decrease calorie intake often by up to 40% (Kerlikowsky et al, 2025). This has resulted in meaningful weight loss for many and a significant increase in GLP-1RA use.


According to KFF polling (Bozick et al., 2025):

  • 1 in 8 U.S. adults (12%) is currently taking a GLP-1 agonist

  • Nearly 1 in 5 (18%) has taken one at some point

  • 20% of women ages 50–64 report GLP-1RA use


With millions using these medications, even moderate increases in nutrient deficiency risk could have substantial public health implications.

 

Can GLP-1 Medications Cause Nutrient Deficiencies?


Yes, GLP-1 medications can cause nutrient deficiencies. The mechanism is straightforward. When appetite is suppressed and food intake drops significantly, intake of protein, vitamins, and minerals declines as well, unless and perhaps even if diet quality is intentionally improved.


GLP-1RAs drive weight loss in part by dramatically reducing overall food intake. While some GLP-1 users eat more nutritious foods than they did previously due to preference or intentional lifestyle changes, less than half (49%) report receiving adequate dietary support from their prescribing provider (Griffiths et al, 2025).

GI side effects, like nausea and diarrhea, can further impair appetite and result in food choices that are palatable and easy to digest. Often, these palatable foods are low in nutrient density, further impairing intake of protein and micronutrients.

Over time, this pattern of insufficient total calories and nutrient consumption increases the risk of both macronutrient and micronutrient deficiencies.



What the Evidence on Nutrient Deficiencies in GLP-1 Users Shows (so far)


Research in this area is still emerging and that’s part of the concern. For medications used by millions, we have surprisingly limited long-term nutrition data. But the data we do have is consistent and concerning.


Urbina et al. (2026) state it plainly:

“Micronutrient deficiencies during GLP-1 therapy are a common consequence rather than a rare adverse effect.”

1. Diagnosed Nutritional Deficiencies Are Common


Butsch et al. (2025) analyzed claims data from over 400,000 GLP-1 users with no prior history of deficiency and found that “over 20% had a diagnosed nutritional deficiency within one year…

"Nutritional deficiencies were diagnosed in 12.7% of the patients within 6 months after GLP-1RA initiation and in 22.4% within 12 months.”

Another study by Urbina et al. (2026) found that the most common nutrient deficiencies were diagnosed starting 6-months after starting a GLP-1 medication and worsened over time. Diagnosed nutrition deficiencies included:

  • Vitamin D

  • Iron

  • Vitamin B12

  • Thiamine (B1)

  • Protein


Muscle loss and anemia were the most commonly diagnosed nutrition-related complications in GLP-1 users in another study, showing how low nutrients can have a real impact on how real people feel each day (Butsch et al., 2025).


2. Intake of Multiple Nutrients Falls Below Minimum Requirements

In addition to diagnosed nutrient deficiencies, emerging data show that GLP-1 users commonly have inadequate intake of:

  • Calcium

  • Iron

  • Magnesium

  • Potassium

  • Choline

  • Vitamins A, C, D, and E


Remember, nutrient DRIs are minimums designed to prevent overt deficiency diseases, not necessarily to support optimal health. If intake drops below even those baseline levels, deficiency diseases become more likely.


It’s also important to recognize that what gets diagnosed depends on what gets tested. If labs to test nutrients aren’t ordered, deficiencies remain undetected.


Why Scurvy and Thiamine Deficiency Are Warning Signs


Scurvy (severe vitamin C deficiency) was once considered eradicated in the U.S. Yet recent media reports describe possible cases among GLP-1 users.


The pathway is biologically plausible:

  • Low fruit and vegetable intake due to reduced appetite

  • Persistent nausea or vomiting further reduces appetite and intake of vitamin C-rich foods

  • Very small meal portions do not provide adequate vitamin C


Similarly, case reports have documented Wernicke encephalopathy and beriberi, serious conditions caused by thiamine deficiency.


These developments are concerning not because they are widespread (they aren’t, yet), but because they suggest a pattern: when intake falls below minimum requirements long enough, deficiency diseases can emerge.


How GLP-1 Nutrient Deficiencies Affect Long-Term Health


Nutrient insufficiency affects far more than body weight. Untreated nutrient insufficiency may have a detrimental effect on:


Bone Health

Low calcium, vitamin D, magnesium, and vitamin K2 impair bone density and fracture resistance.


Muscle Mass and Metabolism

Insufficient protein intake can lead to loss of lean body mass, increasing frailty risk, and slowing metabolic rate.


Mental Health and Energy

Low iron, B12, magnesium, and vitamin D contribute to fatigue, brain fog, low mood, and sleep disturbance.


Thyroid and Metabolic Function

Iron, selenium, and zinc are required for proper thyroid hormone conversion.


Immune Function

Protein, zinc, vitamin A, vitamin D, and vitamin C are critical for immune resilience.


Why Monitoring and Guidance Matter


Despite the massive scale of GLP-1 prescribing:

  • Long-term nutrition research remains limited

  • Standardized nutrient monitoring protocols are lacking

  • Many patients receive little dietary counseling


Given the mechanisms involved, proactive monitoring should be standard care. Here are some labs to consider requesting from your provider that can help to monitor your nutrient status, if your provider is not monitoring them already:

  • CBC and CMP

  • 25(OH) vitamin D

  • Ferritin and iron panel

  • Vitamin B12 (± MMA) and folate

  • Thiamine (especially if experiencing nausea/vomiting or rapid weight loss)

  • Magnesium (RBC) and zinc

  • HbA1c and fasting insulin (especially if diabetic, prediabetic, or struggling with symptoms of hypoglycemia)

  • Albumin/prealbumin (contextual markers of protein status)


Reassessment every 3–6 months early in GLP-1 therapy may help identify emerging deficiencies before they become clinically significant.


Other considerations:

  • The NIH Office of Dietary Supplements database (https://ods.od.nih.gov) provides deficiency symptoms for each nutrient. If you have a symptom that developed since starting a GLP-1 medication, look it up and discuss it with your provider.

  • Insurance may not cover all costs of nutrition related testing. Monitoring is part of responsible GLP-1 care, so patients who choose to pay for GLP-1 medications should account for the added cost of testing to detect and monitor nutrient deficiencies.


 How to Prevent Nutrient Deficiencies While on GLP-1 Medications


1. Prioritize Adequate Protein

Aim for approximately 1.2–1.6 g/kg/day (distribute ~25–40 g per meal). Protein preserves lean mass, steadies appetite, and supplies amino acids necessary for detoxification, neurotransmitter synthesis, and immunity.

  • Easy options when appetite is low: Greek yogurt or cottage cheese; eggs; chicken salad; soft tofu or tempeh; whey or pea protein shake; blended soups with added collagen + strained lentils/beans; tuna pouches; tender stews or slow‑cooker meats.


2. Focus on Nutrient-Dense Foods

When total intake is lower, nutrient density matters more. Make every bite count by emphasizing:

  • Protein-rich whole foods, like meat, seafood, shellfish, eggs, and dairy

  • Leafy greens and colorful vegetables

  • Citrus and berries (vitamin C)

  • Beans and lentils

  • Nuts and seeds


My Rule of Thirds diagram can provide a visual to help plan and build meals.

  • If textures are challenging due to nausea, lean into bone broth, blended soups, smoothies, yogurt bowls, and tender stews.


3. Supplement Strategically

Food first, but supplementation is almost certainly necessary. Under clinician guidance, consider:

  • A high-quality multivitamin and mineral supplement as a “safety net”, especially while food intake is low

  • Vitamin D3 (dose to optimal blood level)

  • B12 (sublingual methyl‑ or adenosyl‑cobalamin) if below optimal on labs (<500) or if symptoms warrant, especially with low animal‑food intake

  • Iron, if confirmed via below-optimal ferritin (<50), especially in the presence of low transferrin saturation and/or low RBC, hemoglobin, hemoglobin concentration

  • Thiamine if vomiting, rapid weight loss, or alcohol consumption (even moderate amounts). Larger doses can be used proactively since this is a water-soluble B-vitamin.

  • Magnesium if intake is low or labs suggest need. May be especially helpful for constipation.

  • Omega-3 (EPA/DHA) if intake is low (hint: it is for most Americans)


4. Incorporate Resistance Training

Without adequate protein and resistance training, 10–25% of weight lost can be skeletal muscle (Heymsfield et al.). Loss of muscle lowers metabolic rate and increases frailty risk. Strength training 2–3 times per week helps preserve lean mass during weight loss.


The Bottom Line: GLP-1 Weight Loss Requires Nutritional Oversight


GLP-1 medications can be powerful tools for weight loss and metabolic improvement. But significant appetite suppression without intentional nutritional planning increases the risk of nutrient deficiencies, and weight loss alone does not equal health.


The scurvy headlines may be anecdotal but the broader trend of declining micronutrient intake among GLP-1 users is real. Deficiencies in vitamin D, iron, B12, thiamine, protein, and others are being documented within months of starting GLP-1 therapy. Despite this,

  • Research is still limited given the scale of GLP-1 use.

  • Nutrition guidance and monitoring remain inconsistent.


Long-term nutrient insufficiency can impair bones, muscles, immunity, thyroid function, mitochondrial energy production, and mental health.

More research is urgently needed. In the meantime:

  • Nutrient-dense eating is non-negotiable

  • Laboratory monitoring is essential

  • Supplementation may be necessary

  • Long-term health must remain the priority


Weight loss without adequate nourishment is not sustainable health. Despite the benefits of GLP-1 medications, without proper nutritional oversight, the long-term risks of deficiency could outweigh the benefits.


This article is for educational purposes only and does not constitute medical advice. Always consult your healthcare provider to individualize monitoring and supplementation.


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