- While GLP-1 drugs like Ozempic, Wegovy, and Zepbound can aid in weight loss, they can also cause nutritional deficiencies.
- When taking a GLP-1 medication, it is important to get enough protein, vitamin B12, vitamin D, iron and calcium.
- Experts share how to address these deficiencies through diet and lifestyle changes.
Losing weight with GLP-1 medications such as Ozempic, Wegovy, Mounjaro, and Zepbound may increase the risk of developing nutritional deficiencies because these medications cause people to eat significantly less.
"If the reduced amount they eat is not nutrient-dense, they may not be getting all the vitamins and minerals they need," Rekha B. Kumar, MD, associate professor of clinical medicine at Cornell and chief medical officer at Found, told Healthline.
If you experience side effects from GLP-1 medications, such as vomiting or diarrhea, you may not be absorbing all the nutrients from your diet.
However, Tara Schmidt, chief dietitian at the Mayo Clinic Diet, says nutritional deficiencies develop over weeks and sometimes even months.
"Most deficiencies likely arise from long-term inadequate intake, such as an overly restrictive diet, malnutrition, or avoidance of entire food groups," she told Healthline.
While there still isn't enough data on nutritional deficiencies specific to people taking GLP-1 drugs, experts say these are the five most common nutritional deficiencies people may experience and what they can do to prevent them.
Not getting enough protein can lead to loss of muscle mass, weakness, edema, hair loss and skin changes.
While recommendations vary based on age, gender, exercise frequency, and health, Dietary Guidelines for Americans recommends that most adults consume about 50 grams of protein per day.
However, for people with obesity who are undergoing weight loss treatment, such as those who have had bariatric surgery, their doctor may recommend as much as 60 to 75 g/day protein.
Kumar encourages her patients taking GLP-1 medications to prioritize eating protein, healthy fats and vegetables, "because they feel full quickly and get the nutrients they need."
Foods high in protein include:
Vitamin D helps the body build and maintain strong bones. The recommended amount of vitamin D for adults aged 19 to 70 is 600 International Units (IE).
If you don't get enough vitamin D, your body may show the following symptoms:
- muscle strain
- Muscle weakness
- Fatigue
- Bone pain
- Tingling sensation in hands or feet
Some foods high in vitamin D include:
- Fatty fish, including trout, salmon, tuna and mackerel
- Beef liver
- Egg yolks
- Cheese
- Milk
Vitamin D helps the body absorb calcium.
Calcium helps the body function in several ways, such as allowing muscles to move and nerves to transmit signals from the brain to the body.
It also helps blood vessels to circulate blood and releases necessary hormones in the body. Adults have about 1,000 mg to 1,2000 mg calcium per day.
Foods high in calcium include milk, yogurt, and cheese.
"For those wanting to avoid dairy, tofu, soy milk, broccoli, some mushrooms and fortified orange juice are other options, but not all contain both nutrients," Schmidt says.
Vitamin B12 helps keep blood and nerve cells healthy and helps make DNA. It also prevents anemia.
Some symptoms of a B12 deficiency include fatigue, headaches, pale or yellow skin, and difficulty concentrating.
The recommended amount of B12 for adults is 2.4 micrograms (mcg).
Vitamin B12 occurs naturally in meat, fish, poultry, eggs and dairy products.
"For people following a vegan diet, this can be a challenge, so it can be helpful to choose fortified products such as grains, meat substitutes and nutritional yeast," Schmidt said.
Iron helps the body grow and develop. It also helps the body make hemoglobin in red blood cells, which carries oxygen from the lungs to the body, and myoglobin, which delivers oxygen to muscles. Iron also makes some hormones.
Grown men need 8 mg iron per day. Adult women need 18 mg until age 51, and 8 mg thereafter.
Some signs of iron deficiency are:
- Fatigue
- Weakness
- Shortness of breath
- Pale or yellow skin
- High heart rate
- Headache
- Brittle nails
Sources of iron include:
- Mussels and oysters
- Lean beef and poultry
- Legumes and lentils
- Whole grain
- Fortified breakfast cereals
- Spinach and kale
"Because iron from plants is not absorbed as well, it is a good idea to combine the iron source with a source of vitamin C; think of spinach salad with strawberries, a lean piece of beef with peppers or iron-fortified breakfast cereal with melon," says Schmidt.
When using GLP-1 medications for weight loss, keep the following tips in mind to ensure you get enough nutrients.
Think about what you drink
Food and beverage choices should provide adequate calories, protein, and hydration in a smaller amount of food, "because eating too much while on a GLP-1 diet can cause nausea or vomiting," Schmidt said.
Adjust your food intake
When starting a GLP-1 or increasing the dose, Schmidt suggested eating soft, blended or liquid meals to help manage symptoms. Consider overnight oats, smoothies, Greek yogurt, soft fruits and protein shakes, which can provide protein, vitamins, minerals, fiber and/or hydration.
Avoid empty calories
Foods and beverages that provide empty calories, meaning lots of calories with little nutritional value, should be avoided. These include sugary drinks, candy, alcohol and ultra-processed snacks. "Ingesting these products can replace the nutrient-dense foods that the body needs," Schmidt said.
Take a multivitamin
Kumar said your doctor may recommend a multivitamin or supplement. Sometimes she recommends her female patients take a prenatal or bariatric supplement if they have significantly reduced their food intake.
"If someone is dehydrated and experiencing cramping, I would recommend drinking water and taking a magnesium supplement," she said.
Monitor your own habits
Tracking how well you hydrate, how many nutrients like protein you consume, how many calories you eat and how much exercise you get will increase your self-awareness and motivate you to make realistic changes, Schmidt says.
Get some help
If you feel that your diet is inadequate, talk to your doctor and a registered dietitian about how you can ensure you are getting enough nutrients.