Tuesday, November 27, 2012

Asparagus Extract Tops Anti-Diabetes Drug Glibenclamide. Plus: Dozens of Add. Health Benefits - From Aphrodisiac to Anti-Hangover & from Neuroprotection to Anti-Aging

Coho salmon, shrimp and asparagus with melted butter - better than any diabetes drug ;-)
Within the last couple of weeks, I have been moving news-items like this one into the "On Short Notice"  category, or simply totally discarded the dozen or so "herb XYZ" or "extract ABC ameliorates hypoglycemia in rodent model of type II diabetes" papers that are published on a weekly basis. The mere number of studies on whatever exotic, herb, spice or isolated polyphenol from the most remote areas (usually in Asia) the names of which I often even have heard about before, is simply too large to cover them all... and let's be honest: In the end, it's also downright boring to read about stuff that decreases blood glucose in a rodent model to a miniscule extend, when you already know that chances that you ever get your hands on a significant amount of that are zero, right?

There are however, two good reasons, why Rahman Md. Hafizur, Nurul Kabir and Sidra Chishti most recent paper, which has been published on November 24 in the latest issue of the British Journal of Nutrition, has still made it not just into the short, but actually the 'official' SuppVersity news are twofold: Firstly, the effects of the Asparagus officinalis extract they administered at two different dosages to their rodents were just mediocre, but - as you are about to see - right on par with the diabetes drug glibenclamide, a sulfonylurea based medication that is often sold in combination with metformin (the respective drugs are called Glucovance and Glibomet). And secondly, briefly summarizing the main results of the study provided a nice incentive to dig somewhat deeper into the already established beneficial health effects of asparagus - and I can tell you, those are about as numerous as the aformentioned boring "herb XYZ"-studies ;-)

From the scientists' petri dishes to the rodent cage and... onto your dishes?

Asparagus officinalis L. is probably what the average Westerner would call "common asparagus". It's native to most European, African and Asian countries and its medicinal usage has been reported in the British and Indian Pharmacopoeias and in traditional systems of medicine such as Ayurveda, Unani and Siddha. Most of you will probably be aware of its mild diuretic effects and the distinct smell of your urine which will betray that you are someone who loves its delicate flavor in salads, vegetable dishes, soups and (if you are like me) poundwise with melted Kerrygold butter, some potatoes a decent amount of ham or some grilled meat during the asparagus season... but I am digressing here, let's get back to the facts.
To get to the bottom of previously reported beneficial effects of asparagus in various inflammatory (metabolic) diseases, the initially conducted an in-vitro study, to test the radical scavenging ability of their Asparagus extract and found that ...
"[...] A. officinalis at a concentration of 0·5 mg/ml exhibited 86·8 % radical-scavenging activity, as shown by a significant decrease in the absorbance of DPPH radicals. These results suggest that A. officinalis has potent antioxidant activity, as the positive control propyl gallate exhibited 91·4 % radical-scavenging activity. (Hafizur. 2012)
Afterwards they injected a group of male and female Wistar rats with streptozotocin to induce diabetes. Subsequently, the rodents received either 250 or 500mg/kg body weight of an Asparagus officinalis (AO) extract or 5mg/kg body weight of glibenclamide (GIB) once daily via an oral syringe - the dosage was adapted once weekly according to changes in body weight.
Figure 1: Fasting blood glucose and insulin levels, total antioxidant status (TAS was measured using the ABTS) and beta cell area / islet expressed relative to control at the end of the 29 day study period (based on Hafizur. 2012)
A cursory glance at the data in figure 1 reveals: The initially betrayed anti-hypoglycemic effects (hypo[...] = ability to lower [blood sugar]) the high dose of Asparagus officinalis extract (AO500, figure 1) had on the fasting glucose levels of the animals were as potent as those of the diabetes drug glibenclamide.  Moreover, the treatment with AO500 had a slightly, but statistically significanty higher impact on the total antioxidant capacity and the same benificial effect on the morphology and function of the pancreas. Nevertheless, neither the A. officinalis extract, nor the glibenclamide treatment were able to restore the compromised insulin producton to more than ~70% of the value the non-streptozotocin-intoxicated animals.

There is much more to asparagus than it's antidiabetic effects

As impressive as these results may be, if we simply rely on the findings Hafizur, Kabir and Chishtiit present in this recent paper, we will actually miss not just half, but rather 95% of the potential health benefits the different genus and parts of asparagus have to offer.

Figure 2: A. racemosis administered at a dose of 200mg/kg per day makes male rats about as horny (and able to perform) as bi-weekly injections of testosterone (Thakur. 2009) - not that you would need that, but it's nice to know anyways.
Despite the fact that asparagus is a highly nutritious source of vitamin B6, calcium, magnesium and zinc, and a very good source of dietary fiber, protein (in at least in view of the fact that it's an almost zero calorie veggie ;-), vitamin A, vitamin C, vitamin E, vitamin K, thiamin, riboflavin, rutin, niacin, folic acid, iron, phosphorus, potassium, copper, manganese, selenium, highly bioavailable chromium, and even small quantities omega-3 fatty acids (Morales. 2012), so that the regular incorporation of asparagus alone into your diet will supposedly be beneficial for you, some of the more intricate health effects may in fact require the extraction of and supplementation with specific phytonutrients from Asparagus officinalis, A. racemosus, A. cochinensis and its various cousins.

In order to give you an idea of what you can expect, I have compiled a comprehensive, yet by no means extensive list of benefits which have been ascribed to root, seed, and even leaf extracts of asparagus over the past decades
  • anti-cancer effects: Asparagus contains saponins that have in-vitro anti-(liver-)cancer effects (Ji. 2012); 
  • neuroprotective effects: Chinese asparagus contains pregnanes that sooth neuro-inflammation (Jian. 2012; compounds could be present in regular A. officinalis as well) and can protect your liver and brain from aging (Xiong. 2011); 
  • antiaging effects: A. contains enzymes that help with protein digestion (Ha. 2012); 
  • hypolipidemic effects: n-butanol extracts from A. officinalis exert anti-hyperlipidemic effects (Zhu. 2011); 
  • antimicrobial effects: A. has antibacterial activity against Escherichia coli, Shigella dysenteriae, Shigella sonnei, Shigella flexneri, Vibrio cholerae, Salmonella typhi, Salmonella typhimurium, Pseudomonas putida, Bacillus subtilis and Staphylococcus aureus (Mandal. 2000); 
  • allows for geno-typing at home ;-) A. allows you to do a personal gene analysis to find out whether you have a single nucleotide polymorphism at rs4481887, which would make it impossible for you to smell the distinct odor the urine acquires after eating asparagus (Pelchat. 2011); 
  • anti-hangover effects: A. helps your liver to metabolize alcohol and can even prevent a hangover (Kim. 2009); 
  • buttery taste: A. contains phytochemicals which generate the sensation of having butter in the mouth (Dawid. 2012); 
  • anti-stress effects: Ethanolic extracts from Asparagus racemosus have anti-stress activity and help your adrenals take a time out (Joshi. 2012)
  • carbblocking effects: Asparagus racemosus inhibits the digestion of carbohydrates and enhances insulin action (Hannan. 2011); in this context it is interesting to remark that the in-vitro essay of the the study at hand suggested that A. officinalis, or rather the specific extract the scientists used in their study "has a very little effect on delaying glucose absorption" (Hafizur. 2012)
  • immune promoting effects: A. racemosus ramps up natural killer cell activity (Thakur. 2012); AR also enhances memory and prevents amnesia (Ojha. 2012), 
  • profound aphrodisiac effects: A dried root extract likewise from A. racemosus more than doubled the 'desire' of male rodents within 29 days (Thakur. 2009; cf. figure 2)
  • MAO and acetylcholine breakdown inhibition: A. racemosus competitively inhibits acetylcholine and monoamine metabolizing enzymes (Meena. 2011)
As this highly incomplete list goes to show you, the health benefits are numerous. Unfortunately, this does also apply to the different phytochemicals which trigger all these effects. The probability that the next best extract you may find on the shelves or virtual outlets of a supplement store is actually going to to yield the health benefits you may be looking for are therefore pretty slim.

Although parts of it are edible as well, A. racemosus, is actually better known for its multitude of beneficial health effects that range from Antibacterial activity (some) antisecretory and antiulcer activity over mood enhancing and anti-depressive properties, and immunomodulatory effects to such profane things as libido enhancement or getting rid of superfluous water before a show or photo shoot.
Bottom line: In view of the practical problems associated with spotting appropriate extracts, I guess it would be best you take the fact that a 2003 paper in scientific journal Nutrition (Pellegrini. 2003) ranked asparagus 7th among 34 fruits and vegetables with respect to its free radical scavenging abilities, as an incentive to simply incorporate asparagus into your diets more frequently.

If, on the other hand, you are dealing with any specific health condition, it would certainly make sense to look for an extract that contains the proper genus of asparagus, is made from the right parts of the plant and - if possible - is even standardized for a specific compound: If you were interested in upping your estrogen levels, you would for example have to pick a whole plant extract of A. dumosus that would at best contain a standardized amount of 20-hydroxecysterone (Kaur. 1998). If it's rather the anti-ulcer effects you are after, your 'asparagus product of choice' should be made of the roots of A. racemosus ideally standardized for its Shatavairin content (Bhatnagar. 2005)... 

And now, you tell me eating healthy was complicated and taking supplements was easy ;-)

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