Several months ago I posted an article about “Prescribing GLP-1 Receptor Agonists,” on DrGOpines.com. In it, I reported that along with weight loss and blood sugar control, patients were experiencing the loss bone mass and muscle mass. Also, because appetite suppression was causing significantly less food intake, deficiencies of multiple micro-nutrients were being reported. Protein, fiber, calcium, potassium, magnesium, vitamins A, C, D, and E, and iron have shown deficiencies attributed to GLP-1-induced weight loss.
Recently, a number of patients on GLP-1’s have developed iron-deficiency anemia which may be linked to taking this class of drugs. It hasn’t been shown conclusively, yet, but since other deficiencies are common, there is a likely connection. Being diabetic and obese at the same time makes individuals prone to anemia. Iron deficiency anemia is the most common type of anemia, and the GI effects of GLP-1’s may be the culprit. Age, lifestyle, degree of blood sugar control, and duration of diabetes are all accompanying factors.
GLP-1’s affect appetite centers in the brain causing people to feel full and not hungry. People then eat fewer calories and far less of the previously-mentioned micro-nutrients, eg. iron, vitamins, minerals. Potentially, iron-deficiency anemia can cause fatigue, weakness, or even postural hypotension (fainting or lightheadedness when going from sitting to standing).
A statement by four major medical societies recommends for patients on GLP-1’s:
A complete baseline nutritional assessment
Management of GI side effects
Supervision of food preferences and intake
Promotion of healthy lifestyle—exercise, diet, adequate sleep
Greater emphasis on intake of fruits, vegetables, whole grains, legumes, protein, nuts, and
seeds
As with all things, along with the GOOD (blood sugar control, weight loss) must come the BAD (bone loss, muscle mass loss, vitamin and mineral deficiencies, iron deficiency). Nutritional therapy by a registered dietician is recommended as a preventive measure, but also close observation by prescribing doctors will help find these deficiencies before they cause problems.
Reference: Yasgur BS. Anemia: A Lesser-known side effect of GLP-1 drugs? Medscape 2025 December 9.
