The Health Benefits of Asparagus Extract

May be helpful for diabetes; risky for those with breast cancer

Asparagus extract capsules

Verywell / Anastasia Tretiak

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Asparagus extract is a natural remedy sourced from the spears, root, and rhizomes (the "underground stem") of the asparagus plant. Asparagus extract is used in alternative and Ayurvedic medicine to treat health problems affecting the urinary tract and other organ systems, including conditions such as diabetes and high blood pressure.

Sold mainly in capsule form, asparagus extract is also available in tea bags, liquid tinctures, and crystallized powders.

Health Benefits

In alternative medicine, asparagus extract is typically used to "detoxify" the bladder and urinary tract. Asparagus is especially high in quercetin, a flavonoid known to have antibacterial, antiviral, and anti-inflammatory properties.

Asparagus is rich in antioxidants such as vitamin E, vitamin C, and polyphenols that help neutralize free radicals that cause damage to cells. Asparagus is also rich in vitamin K (which plays a role in blood clotting), folate (needed to sustain a healthy pregnancy), and an amino acid called asparagine (essential to normal brain development).

Proponents believe that asparagus extract can prevent or treat a host of unrelated health conditions, including:

Some of these claims are better supported by research than others. A few are largely conjecture, while several of these border on pseudoscience.

Asparagus extract is thought to amplify the benefits of asparagus simply because it is concentrated. Clinical research has shown that this isn't always so. Certainly with regards to digestive health, the insoluble fiber found in asparagus—thought to prevent constipation and reduce the risk of colon cancer—is all but missing in asparagus extract.

This shouldn't suggest that asparagus extract is without health benefits; it is simply that clinical studies investigating asparagus extract are sorely lacking.

Here is what some of the existing research says about its potential.

High Cholesterol

A number of studies have concluded that asparagus extract may help reduce cholesterol levels that contribute to heart disease,

According to a 2011 study published in Phytotherapy Research, mice fed a high-fat diet supplemented with asparagus extract experienced a significant decrease in LDL ("bad") cholesterol and an increase in HDL ("good") cholesterol after eight weeks.

The effect was attributed to a substance called n-butanol, which the researchers say improves liver function and increases the organ's ability to produce and clear cholesterol. Further research is needed to see if similar results can be achieved in humans.

Diabetes

Asparagus extract may help fight diabetes, suggests a 2012 study from the British Journal of Nutrition. In tests conducted on rats with chemically induced diabetes, scientists found that asparagus extract helped normalize blood glucose levels and improve insulin secretion. Higher doses conferred better results.

The effect was attributed in part to the trace element chromium which insulin uses to transport glucose through the body. Human research is needed to further support this effect.

Stress

Asparagus extract may help relieve symptoms of stress, suggests a 2014 study in the Journal of Food Science. According to the investigators, mice subjected to sleep deprivation had normal levels of stress biomarkers (such as cortisol and lipid peroxide) in their blood after having been given asparagus extract. Untreated mice showed high elevations of all of these biomarkers.

The scientists also tested the extract on a small group of humans who were given a daily 150-milligram (mg) dose for seven days. At the end of the trial period, the subjects experienced significant increases in a protein called HSP70, which tempers the effect of cortisol and other stress hormones.

By doing so, asparagus extract may help mitigate the physiological impact of stress, such as high blood pressure, fatigue, and mental "fog." The study does not, however, suggest that it can either reduce stress or deliver "calming" psychoactive effects. Further research is needed.

Possible Side Effects

Even though asparagus is safe when consumed as food, little is known about the long-term safety of asparagus extract. What little research there is has shown it to be safe and well-tolerated when used for up to seven days.

Side effects may include increased urination and smelly urine, particularly with supplements that have high concentrations of asparagusic acid.

Not enough is known about the safety of asparagus in children, pregnant women, or nursing mothers. As a precaution, it is best for these individuals to avoid asparagus extract and eat fresh asparagus instead.

Breast Cancer Warning

When buying asparagus extract, the two ingredients often highlighted on the product label are asparagine and glutamine. Asparagine is thought to enhance athletic performance and improve brain function, while glutamine is considered one of the body’s more potent anticarcinogens.

These two compounds appear to have contradictory effects insofar as cancer is concerned.

According to a 2018 study in Nature, asparagine actually shields cancer cells from the effects of glutamine and promotes, rather than inhibits, the spread of breast cancer. The investigator found that exposing breast cancer cells to increasing concentrations of asparagine in the test tube triggered metastasis (the spread of cancer), while the restriction of asparagine reduced this risk.

Though asparagus and asparagine-rich supplements in no way "cause" cancer or promote tumor growth, they may increase the risk of metastasis in women with breast cancer.

The scientists concluded that the risk was associated not only with asparagine found in foods like asparagus but also with asparagine-rich supplements and extracts.

As such, asparagus extract should also be avoided in women with breast cancer due to the increased risk of metastasis. Its effect on other types of cancer is unknown.

Interactions

Because of its diuretic effects, asparagus extract may reduce the concentration of lithium in the blood and, with it, the drug's effectiveness.

Asparagus extract may enhance the effects of diuretics such as Lasix (furosemide), causing excessive urination and side effects.

Asparagus extracts should be used with caution if taking anti-diabetes medications, including insulin, as they may cause a steep drop in blood sugar (hypoglycemia).

As it is unknown how potent these interactions may be, advise your doctor if you are taking asparagus extract and any prescription or non-prescription drugs.

Dosage and Preparation

There are no guidelines for the appropriate use of asparagus extract. Dosages of up to 150 mg per day have been used in short-term studies with no reported side effects.

Most asparagus extract formulations are between 150 mg and 650 mg. As a rule of thumb, never exceed the recommended dose on the product label. If anything, start with the smallest possible dose and increase it incrementally as tolerated.

Capsules are the easiest form to take as the dose is consistent. If using powders or tinctures, always measure the doses accurately rather than "eyeballing" them.

Asparagus extract teas are generally used as an Ayurvedic health tonic.

If taking asparagus extract to help control blood sugar or cholesterol, let your doctor know so your levels can be monitored along with any adverse interactions or side effects.

What to Look For

Asparagus extract can be readily found online as well as in many natural food stores, drugstores, and shops specializing in dietary supplements.

Because dietary supplements are not strictly regulated in the United States, opt for brands that have been voluntarily submitted for testing by independent certifying bodies like the U.S. Pharmacopeia (USP), ConsumerLab, and NSF International.

Certification does not guarantee safety or efficacy, but it does confirm that what is in the bottle matches what is listed on the label. (Some supplements have been found to contain additional ingredients, metals, and other toxins.)

You can further reduce the risk of toxic exposure by choosing supplements that have been certified organic by the U.S. Department of Agriculture (USDA).

Always check the product label for ingredients you may be sensitive to or otherwise want to avoid, such as wheat fillers, animal-based gelatins, or preservatives.

Most asparagus extracts can be safely stored at room temperatures, including liquid tinctures that contain up to 40% alcohol. Never use a supplement past its expiration date.

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