Asparagus Has A Nutritional Uniqueness that is Second to None
Researchers have identified nearly 100 phytonutrient compounds in asparagus:
- Organic acids
- gluconic acid
- malic acid
- nonanedioic acid
- Oxylipins
- dihydroxy-octadecanedioic acid
- trihydroxy-octadecanedioic acid
- hydroxyperoxy-octadecanedioic acid
- Saponins
- asparanin A
- protodioscin
- sarsasapogenin
- Lignans/Norlignins
- secoisolariciresinol
- iso-agatharesinoside
- Amino Acids
- asparagine
- Phenolic acids
- vanillic acid
- caffeic acid
- coumaric acid
- ferulic acid
- Flavonoids
- apigenin
- noricaritin
- isorhamnetin
- kaempferol
- Other
- asparagus acid
- rhodioloside D
Of course, not shown in the list above are more common flavonoids (like quercetin and rutin) as well as the conventional 8 nutrients: vitamin K, folate, copper, vitamin B1, selenium, vitamin B2, vitamin C and vitamin E; very good rankings go to 12 additional nutrients: fibre, manganese, phosphorus, vitamin B3, potassium, choline, vitamin A, zinc, iron, protein, vitamin B6, and pantothenic acid; and good rankings go to 2 additional nutrients: magnesium and calcium. In other words, not only does asparagus contain the unusual list of phytonutrients presented in the chart above, but it also ranks as a good, very good, or excellent source of 22 of the 29 nutrients.
One of the unique phytonutrients in asparagus is asparagusic acid. Asparagusic acid is the compound responsible for the urine odour that many people associated with asparagus. In chemical terms, asparagusic acid (1,2-dithiolane-4-carboxylic acid) is unusually reactive due to the two sulfur atoms that are positioned adjacent to each other in the molecule. Among other things, this increased reactivity helps asparagusic acid break down rapidly and its derivatives are what researchers believe we smell after asparagus has been consumed. However, it's important to note that people differ in three basic ways in terms of asparagus consumption and urine odor. First, there are differences in digestion while asparagus is inside our GI tract and differences in the absorption of asparagusic acid. Second, there are differences in the way we metabolize asparagusic acid if it gets absorbed up into our bloodsteam. And finally, there are differences in our ability to detect the presence of asparagusic acid derivatives. These factors can combine in such a way as to produce some unusual results. For example, one person might end up with significant amounts of asparagusic acid derivatives in his or her urine, but be unable to detect the odor, even when another person can!
Anti-Inflammatory and Antioxidant Benefits of Asparagus
It's not surprising to see asparagus being heralded as an anti-inflammatory food because it provides a truly unique combination of anti-inflammatory nutrients. Among these anti-inflammatory nutrients are asparagus saponins, including asparanin A, sarsasapogenin, protodioscin, and diosgenin. In this anti-inflammatory context, it is worth noting that recent research on the shatavarins in asparagus (shatavarin I, II, III, and IV) has revealed another group of saponins that influence inflammation through cytokine messaging. These asparagus saponins are able to inhibit production of cytokines IL-6 (interleukin-6) and TNF (tumor necrosis factor) and in this way help reduce excessive inflammatory processes.
In the antioxidant category of health benefits provided by asparagus glutathione (GSH) and rutin are at the top of the list. GSH is one of the body's premiere antioxidant molecules, which consists of three amino acids—glutamic acid, cysteine, and glycine—linked together; GSH is known as a tripeptide because it composed of three amino acids. GSH is so important as an antioxidant that its depletion within our cells is sometimes used to measure overall oxidative stress. GSH also plays a critical role in phase 2 of our body's detoxification processes.
Asparagus is also rich in one particular antioxidant flavonoid called rutin. Rutin has been especially interesting to researchers because of the special role it may play in Maillard reactions. In the kitchen, Maillard reactions are familiar to us as the browning reactions that take place when the sugars in food react with amino acids. (The browning of bread when toasted is a good example here.) When rutin is present during the Maillard reaction process, it may become involved with the Maillard reaction products in such a way as to increase free radical scavenging and to lower risk of oxidative stress.
The polysaccharides in asparagus are also important to include in this section on antioxidant and anti-inflammatory health benefits. Polysaccharides are a very common type of complex carbohydrates, and you will sometimes hear them being referred to simply as "starches." Most of the polysaccharides analysed in asparagus to date involve the inulins and heteroxylans.
How to Enjoy - A Few Quick Serving Ideas
- Add cold asparagus to your favourite salad.
- Toss freshly cooked pasta with asparagus, olive oil and your favourite pasta spices. We especially enjoy thyme, tarragon and rosemary.
- Chopped asparagus make a flavorful and colourful addition to omelettes.
- Healthy saute asparagus with garlic, shiitake mushrooms and tofu or chicken for a complete meal.