What is asparagus?

Asparagus, known by its scientific name Asparagus officinalis, is a long, green spring vegetable.¹

Asparagus was reportedly cultivated as early as 3000 B.C. and contains a ton of micronutrients. This spring vegetable is a good source of manganese, folate, iron, vitamin K, vitamin C, vitamin B1, and vitamin B6.² It is made up of 93% water, with 2 grams of protein, 4 grams of carbohydrates, and 0 grams of fat. With a low macronutrient density, 5 asparagus spears equate to only 20 calories.³ It, further, has a glycemic index scale rating of 1, making it a viable food option for those looking to lose weight.⁴

What are the health benefits of asparagus?

Asparagus is known for its antioxidant effects, anti-inflammatory properties, promotion of good digestive health, and for promoting heart and bone health.⁵ Fiber provides anti-inflammatory benefits and aids in proper digestion.⁶ 100 grams of asparagus contains 2-3 grams of inulin, a type of dietary fiber. Inulin is a great prebiotic and helps promote and activate the good gut bacteria that aids in proper nutrient absorption and digestion.

Asparagus provides high amounts of vitamin K and folate. High levels of vitamin K contribute to reduced bone fracture risk and increased bone density (particularly in those with osteoporosis). It also promotes heart health. Folate is a micronutrient that is important in DNA methylation and thus has preventative cancer and cardiovascular effects.⁷ Folate also reduces congenital disabilities and is important during pregnancy.

Asparagus also contains high levels of vitamin C and vitamin B. Vitamin C is an antioxidant and prevents cancer risks and cardiovascular disease, and is also present in high amounts in asparagus.⁸ B vitamins contribute to energy levels and normal cell function.⁹ Interestingly, asparagus also acts as a natural diuretic, increasing the production of urine and helping to excrete excess fluids and waste from the body.

The high levels of sulfur in asparagus support glutathione synthesis. Glutathione is a powerhouse antioxidant and combats oxidation, thus reducing cancer risk, and contributes to optimal immune function. Studies have also shown that the anti-inflammatory and anti-oxidative behavior of asparagus results from the ability to specifically neutralize hydroxyl and nitric oxide free radicals due to increases in antioxidant enzymes catalase and superoxide dismutase after asparagus consumption.^10,11 Thus, asparagus appears to promote anti-oxidant enzyme synthesis. One reason for this could be due to the presence of manganese in asparagus, as manganese supports superoxide dismutase synthesis.

Recent studies have explored the impact of asparagus on insulin and blood glucose levels.¹² Numerous studies concluded that the vegetable plays a significant role in improving insulin sensitivity and consequently, blood glucose levels.¹³ Reasons for this are unclear, but this could be due to the micronutrient and fiber content of asparagus. Other studies have shown that asparagus helps reduce blood pressure via the presence of the compound 2”-hydroxynicotianamine, which is an angiotensin-converting enzyme (ACE) inhibitor.¹⁴

The nutrients in this power vegetable, such as vitamin C, vitamin E, silica, and sulfur, also, surprisingly, help combat eczema.¹⁵ Eczema is a skin condition categorized by inflammation and rash-like symptoms. Diets high in vitamin C reduce water loss in the skin and play a significant role in proper wound healing. Silica helps form connective tissue contributing to healthy skin. Sulfur is further necessary for the production connective tissue, such as collagen. Sulfur and vitamin E protect the skin from damage via anti-oxidant and anti-inflammatory pathways. Lastly, asparagus has been shown to aid in liver protection and regeneration.¹⁶

So, what is the best way to eat asparagus?

Asparagus has an array of benefits, but what is the best way to reap its nutritional value? It is known that the nutrient content of vegetables can vary depending on whether the vegetable is cooked or raw. Some nutrients are increased when the vegetable is cooked; others are decreased when cooked, and thus better eaten raw. Furthermore, eating raw vegetables can have a beneficial impact on the gut biome (the bacteria profile and number in the gut) due to the fiber content. However, if you have gut issues, it is recommended to avoid raw vegetables.¹⁷ People with gut issues tend to have a harder time digesting raw foods, and this often results in gas, bloating, and an upset stomach. Cooking vegetables helps to break down cellulose, allowing for better and smoother digestion.¹⁸ While a combination of cooked and raw is often best, when it comes to asparagus, cooking is highly recommended.

Cooking asparagus increases its antioxidant content, and various studies and sources point out that, in order to receive the cancer-fighting and anti-inflammatory benefits of asparagus, cooking is better.¹⁹ Cook asparagus on spears for a maximum of 3-5 minutes to gain the most benefits. However, be careful not to cook too long, as long exposures to high temperatures can eventually reduce the anti-oxidant content of asparagus.²⁰

Another reason to avoid raw asparagus is due to the presence of saponins (this is also why raw asparagus has a bitter taste). Saponins are compounds produced by plants and grains to ward off predators, bacteria, and fungi.²¹ Saponins have the potential to create holes in cell membranes, causing leaky gut, and they have been associated with inflammatory and autoimmune conditions.²² Grains and legumes have the highest saponin content, causing many healthcare professionals to recommend limiting these foods. Asparagus does have saponins, however, the amount is much lower than that present in grains. Furthermore, cooking reduces saponin content, so cooking would be the ideal way to consume this vegetable.²³

Is there a downside to asparagus?

Not really. If there are any, the benefits drastically outweigh the downsides. The potential downsides that we can think of are as follows, and they are most likely not concerning:

1. As stated above, the saponin content of asparagus is not ideal. However, cooking solves this problem.
2. A more common deterrent for its consumption is the sulfur smell in urine associated with asparagus. However, this is a side effect of sulfur metabolism and is harmless; the only inconvenience is more potent smelling urine.²⁴ For most, this is not a huge deal.
3. Asparagus does contain high levels of glutamic acid and asparagine. Some studies have linked these amino acids to increased cancer risk, although these studies are done in the lab with mice as their subjects. Thus, they may not accurately portray what happens in the human body. Confounding factors may also complicate these studies, and thus their results should be interpreted with caution. Furthermore, glutamic acid is essential for neurotransmission and immune system regulation, and asparagine is necessary for protein synthesis and function. Many argue that these benefits outweigh the potential negative aspects.

The Bottom Line

Asparagus, specifically cooked asparagus, is an incredibly healthy vegetable and food choice. Include asparagus into your meals a few times a week!

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