Eating asparagus benefits your body in several ways. This vegetable is low in calories and rich in B vitamins, antioxidants and vital minerals. However, a trip to the bathroom after eating a few stalks may reveal minor side effects, such as gas and smelly urine.
Asparagus Nutrition Facts
Asparagus benefits your health due to its high nutritional value. This veggie is chock-full of beta‐carotene, lutein, zeaxanthin and phenolic compounds. When consumed as part of a balanced diet, it may help maintain the health of your eyes, reduce cholesterol and potentially protect against cardiovascular disease, diabetes and age‐related cancers, notes Ohio State University.
According to the USDA, one 180-gram cup of cooked asparagus contains approximately 40 calories, no cholesterol and negligible fat. This vegetable is low in carbohydrates and has just 7.4 grams per cup, or 2 percent of the daily value (DV). It also provides 4.3 grams, or 9 percent of the DV of protein.
Asparagus is also rich in B vitamins, which your body needs to produce energy required for the functioning of all your organs, muscles, skeletal system and brain. The B vitamins in this vegetable include:
- Folate: 268 micrograms or 67 percent of the DV
- Thiamin: 0.3 milligrams or 24 percent of the DV
- Riboflavin: 0.3 milligrams or 19 percent of the DV
- Niacin: 2 milligrams or 12 percent of the DV
- Pantothenic acid: 0.4 milligrams or 8 percent of the DV
- Vitamin B6: 0.1 milligrams or 8 percent of the DV
This superfood contains many vitamins that act as antioxidants in your body. Antioxidants neutralize harmful free radicals that contribute to oxidative stress and chronic diseases. Vitamins in cooked asparagus that keep your immune system strong include:
- Vitamin C: 14 milligrams of 15 percent of the DV per cup
- Beta carotene: 1,087 micrograms or 10 percent of the DV per cup
- Vitamin E: 2.7 milligrams or 18 percent of the DV per cup
A one-cup serving of asparagus is also a good source of vitamin K — providing 76 percent of the DV — and vitamin A — with 60 percent of the DV.
Like vitamins, minerals are important for your body's growth and development. These nutrients keep your bones strong, transmit nerve impulses, control muscle contractions and maintain the rhythm of your heartbeat. Each cup of asparagus provides:
- Calcium: 41.4 milligrams or 3 percent of the DV
- Iron: 1.6 milligrams or 9 percent of the DV
- Magnesium: 25 milligrams or 6 percent of the DV
- Phosphorus: 97 milligrams or 8 percent of the DV
- Potassium: 403 milligrams or 9 percent of the DV
- Zinc: 1.1 milligrams or 10 percent of the DV
- Copper: 0.3 milligrams or 33 percent of the DV
- Selenium: 11 micrograms or 20 percent of the DV
Asparagus Is Rich in Fiber
Cooked asparagus is an excellent source of fiber. The 2015-2020 Dietary Guidelines for Americans recommends the consumption of 22 to 33 grams of fiber each day, depending on your age and gender. A one-cup serving of cooked asparagus contains 14 percent of the daily recommended fiber intake.
Dietary fiber remains undigested in your gut, adding bulk and absorbing water that helps soften digested food so it can pass smoothly through your digestive system and out of your body. This not only keeps you regular, but it can also lower your risk of hemorrhoids and ease the symptoms of irritable bowel syndrome and diverticulitis.
Asparagus contains a special type of dietary fiber called "inulin." This nutrient is not digested or absorbed by your stomach but supports the growth of good gut bacteria that are associated with proper bowel function. When consumed as part of a balanced diet, it may also improve blood lipids.
If you're following a weight-loss plan, the fiber in asparagus may help. This nutrient slows down digestion, keeping you full longer. The appetite-suppressing effect of asparagus could help reduce the urge to snack and decrease your daily calorie intake.
However, if you are not used to eating a high-fiber diet, be cautious about consuming too much asparagus, as side effects may result, including gas, abdominal bloating and cramping. By introducing fiber gradually into your diet, you can avoid digestive discomfort.
Asparagus and Smelly Urine
If you've noticed a pungent odor coming from your urine after you eat asparagus, you're not alone. This vegetable contains a chemical compound called "asparagusic acid," according to a January 2014 review published in Phytochemistry. When you digest asparagus, this chemical breaks down into sulfur-containing compounds that are responsible for the strong unpleasant odor of your urine.
But as strange as it may sound, not everyone smells the stinky pee. Scientists are not exactly sure why this is. Two possible explanations for this are: not all people excrete smelly compounds in their urine after eating asparagus, or not all people can smell the compounds. Scientists speculate that genetics may be involved in this phenomenon.
In December 2016, data was examined from the "Nurses' Health Study," which involved nearly 7,000 participants, to determine the inherited factors associated with smelling asparagusic metabolites in urine. The findings, which were published in the BMJ, reported that more than half of the participants could not distinguish the strong characteristic smell.
Researchers believe that genetic variations of olfactory receptors were associated with the ability to detect the smell. Whether you can smell it or not, there are no harmful effects to producing or smelling the odorous results of eating asparagus.
Fructan Intolerance and Asparagus Allergy
If eating a few stalks of asparagus gives you stomach pain, you may have an intolerance to fructan, a carbohydrate in this food. Since the symptoms are similar to those of gluten sensitivity, intolerance to fructan is often misdiagnosed, warns Ohio State University.
Fructan intolerance is common. A study cited in a manuscript published in Current Gastroenterology Reports in January 2014 estimates that up to one-third of people with suspected irritable bowel syndrome (IBS) actually have fructan malabsorption and dietary fructan intolerance.
Although wheat and onions are the most common sources of fructan, some vegetables, including asparagus, contain this compound too. If you have trouble digesting fructans, you may experience symptoms like:
Symptoms can range from mild to severe enough to necessitate missing work or school, according to Ohio State University.
It is also possible for some people to be sensitive to asparagus because of a food allergy to the Alliaceae family of vegetables, which includes garlic, onions, chives and leeks in addition to asparagus. Each member of the family has the potential of cross-reactivity with each other and may trigger allergic reactions.
At least six IgE compounds have been detected in raw asparagus. Immunoglobulin E (IgE), for example, is an antibody produced by your immune system in response to overreacting to an allergen. This compound releases chemicals in your cells, causing an allergic reaction that may induce symptoms affecting your skin, throat, nose or lungs.
Severe allergic reactions may cause life-threatening anaphylaxis, which requires immediate medical attention.
- MyFoodData: "Nutrition Facts for Asparagus (Cooked)"
- Health.gov: Dietary Guidelines for Americans, 2015-2020: "Appendix 7. Daily Nutritional Goals for Age-Sex Groups Based on Dietary Reference Intakes and Dietary Guidelines Recommendations"
- International Foundation for Gastrointestinal Disorders: "Dietary Fiber"
- Mayo Clinic: "Diet, Lifestyle Choices can Lower Risk of Diverticulosis Developing into Diverticulitis"
- Ohio State University: "Maximize Your Nutrients From Asparagus"
- Mayo Clinic: "Dietary Fiber: Essential for a Healthy Diet"
- The BMJ: "Sniffing Out Significant “Pee Values”: Genome Wide Association Study of Asparagus Anosmia"
- Ohio State University: "Should You Avoid Eating Fructans?"
- Current Gastroenterology Reports: "Dietary Fructose Intolerance, Fructan Intolerance and FODMAPs"
- Thermo Scientific: "Asparagus"
- American Academy of Allergy, Asthma and Immunology: "Immunoglobulin E (IgE) Definitions"
- Nutrients: "Lutein and Zeaxanthin—Food Sources, Bioavailability and Dietary Variety in Age-Related Macular Degeneration Protection"
- Journal of Traditional and Complementary Medicine: "Improvement of Blood Pressure, Glucose Metabolism, and Lipid Profile by the Intake of Powdered Asparagus (蘆筍 Lú Sŭn) Bottom-Stems and Cladophylls"
- American Optometric Association: "Lutein & Zeaxanthin"
- Phytochemistry: "Asparagusic Acid"
- RXList.com: "Inulin"