What Causes Some Vegetarians to Become Nauseous and Dizzy?

Updated October 5, 2022
Nauseous young woman lying on the couch holding her head with hand

If you're following a vegetarian diet and feeling nauseous or dizzy, you may be wondering if your diet is to blame or if a medical condition is the culprit. A variety of things can cause these symptoms in vegetarians, and a lack of certain nutrients could be the cause. For example, deficiencies in iron, vitamin B12, and vitamin D can contribute to dizziness or nausea, and these nutrients can run low in a vegetarian diet.

Other diet-related reasons for dizziness and nausea could include dehydration or low blood sugar, but a vegetarian diet should not put you at greater risk for this. If you feel nauseous or dizzy and you follow a plant-based diet, consider any of these potential causes, and reach out to a registered dietitian and your healthcare provider to get personalized guidance.

1. Iron Deficiency

Iron is a key nutrient for vegetarians, and iron deficiency can cause you to feel lightheaded, nauseated, and dizzy. Vegetarians have increased risks for iron-deficiency anemia simply because meat is a main source of dietary iron. Foods rich in iron include lentils, spinach, iron-fortified breakfast cereals and other grains, white beans and kidney beans, peas, and raisins. Speak to your healthcare provider for guidance about taking iron supplements.

2. Vitamin D Deficiency

A 2021 review reports that vitamin D deficiency may be associated with vertigo, a condition that can cause nausea and dizziness. Vitamin D is an important nutrient for vegetarians, especially for those who avoid dairy foods which are often fortified with it. Foods rich in vitamin D include vitamin-D enriched breakfast cereal, orange juice, soy milk, almond milk, or any plant-based milk. Certain mushrooms exposed to ultraviolet light are good sources of vitamin D.

Sunlight exposure is another way to meet daily vitamin D needs, but this is not a reliable solution for people with darker skin tones who require more time in the sun to convert sunlight to vitamin D and people living in northern latitudes. The ability of skin to absorb and convert sunlight to vitamin D declines with age.

Consider having your blood levels of vitamin D checked regularly, and follow your healthcare provier's advice about supplementation to reach and maintain healthy levels of vitamin D.

3. Vitamin B12 Deficiency

Although uncommon, a condition called vitamin B12 deficiency anemia can cause dizziness in vegetarians who don't eat enough vitamin B12-rich foods. Vegetarians can get vitamin B12 from food or supplements. Food sources of vitamin B12 for vegetarians include fortified breakfast cereal, milk and fortified plant-based milks, yogurt, cheese, nutritional yeast, and eggs. See your healthcare provider for treatment options.

4. Dehydration

Being dehydrated can cause of nausea and dizziness, and vegetarians can be at risk for dehydration as much as meat eaters. Causes of dehydration include being sick, certain medical conditions, certain medications and excess sweating.

To help avoid dehydration, be sure to increase fluid intake in hot weather conditions and when you're sick. If you experience dizziness or nausea due to dehydration, it's important to replace the fluids as well as the electrolytes that help balance the body's fluids, such as potassium and sodium. Water along with sports drinks can help, but be sure to seek medical help if you experience rapid breathing or heart rate, confusion or fainting.

5. Low Blood Sugar

Regardless of whether or not you're vegetarian, low blood sugar can be a cause of dizziness, nausea, and even fainting. If you're experiencing dizziness and are taking diabetes medications, ask your healthcare provider to evaluate your medication dosage and meal plan.

Skipping meals or exercising can cause low blood sugar. Eat regular meals or snacks spaced evenly throughout the day to help keep blood sugar in check. If you have diabetes, follow your doctor's protocol for managing your low blood sugar. Otherwise, you can boost blood sugar and keep it a bit more stable by eating a carbohydrate-containing food such as fruit or whole grains along with some protein and fat, such as a sliced apple spread with 1 tablespoon peanut butter.

6. Medical Conditions

If you're getting all the essential nutrients your body needs daily, eating regular meals, and drinking plenty of water, certain medical problems may be the cause of your nausea and dizziness.

Dizziness and nausea right after eating can be linked to postprandial hypotension. This condition is more common in older adults, and it's due to an increase in blood flow to the digestive tract, leaving less blood flow in the rest of the body. Although not linked specifically to a vegetarian diet, one strategy that can improve symptoms is eating six small meals rather than three larger meals.

According to The National Institutes of Health, certain medical conditions may cause dizziness and sometimes nausea:

  • A cold
  • Allergies
  • Flu
  • Heart problems
  • Low blood sugar
  • Low blood pressure

See your healthcare provider if you have unexplained dizziness. If you experience chest pain, confusion or loss of consciousness along with dizziness, seek medical help right away.

7. Medications

Taking certain medications, such as anti-convulsant medication, is another common cause of nausea and dizziness. Be sure to check the warning label on your pills to see if your symptoms are related to your meds. Always talk to your doctor before discontinuing prescribed medications.

While vegetarians are at risk for nausea and dizziness if they have certain medical conditions, diet related symptoms can be managed by planning for these important nutrients. Any form of dizziness poses a risk for fainting, falls, and other injuries, so if you're feeling dizzy seek medical attention to determine the cause and appropriate treatment.

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What Causes Some Vegetarians to Become Nauseous and Dizzy?