Astragalus is a herb which has attracted a lot of attention in recent years. Here I will have a look at the current claims and supporting evidence for the health benefits of astragalus.
Can astragalus make you live longer?
This is the biggest claim I see for astragalus, and to first understand the origin of this claim, you need to understand a key part of the ageing process. At the end of all DNA strands are bits of DNA which don’t code for anything, and these are called telomeres. Although they don’t code for anything, they have a very important role in protecting the rest of the DNA from damage or tearing. They are a kind of shield, if you like. The telomeres themselves will get damaged by radicals/ tear regularly, and we actually have an enzyme in the body which repairs the telomeres, called telomerase. Keeping telomers in good condition protects the DNA from being damaged, and DNA damage from various sources such as radicals is thought to be a major cause for the development of signs of ageing, such as wrinkles/ bad joints.
As the years go by, these telomers naturally shorten in length, which reduces the amount of protection our DNA has, and so naturally we begin to show the typical signs of ageing develop. These signs of ageing can be reduced/ sped up depending on how much radical damage our body experiences. Smoking or excessive use of sun beds will obviously increase the amount of radical damage (ever seen a well tanned person with loads of wrinkles?), whereas eating plenty of fresh fruit/ veg should slow down the signs of ageing. Ultimately though, telomere length is crucial for protecting DNA and reducing the onset of the signs of ageing – the longer the telomeres are, the more protection your DNA has.
Astragalus is a unique source of a compound called cycloastragenol (or TA-65), which has been shown to activate the telomerase enzyme. This will help reduce the rate at which telomeres shorten, or even possibly lengthen the telomeres, which can reduce signs of ageing.
One study found that TA-65 was able to induce telomerase activity 1.4-3.3x fold relative to control groups, and other compounds in astragalus also acted as telomerase activators, but to a lesser extent1. A separate study showed that treatment with TA-65 resulted in telomerase-dependent elongation of short telomeres and rescue of associated DNA damage2, showing that TA-65 can lengthen telomeres, and reduce DNA damage associated with short telomeres.
Admittedly studies are sparse, but current findings are very promising and have shown some clear results. Compounds found in astragalus have been shown to activate telomerase and protect against the onset of the signs of ageing. The EFSA (European Food Safety Authority), have evaluated the data themselves and have concluded that astragalus can “protect cells and tissues from oxidative damage” 3. Which is essentially the role of telomeres.
This current evidence doesn’t show an increase in life-span as much as an increase in health-span though – which are different. Health-span is a measure of how long you are healthy, whereas life-span is a measure of age, and astragalus hasn’t necessarily shown an increase in life-span. However, I can imagine that delaying the onset of the signs of ageing is attractive to anyone, and who wants to live forever anyway?
Other benefits of astragalus
In China astragalus tea is given to treat any number of ailments from foamy/ bubbly urine to a cold. I would be tempted to dismiss this as anecdotal evidence, but lets not forget that the benefits of green tea, turmeric and even the pain relief claims of asprin (originated from willow bark) started off as anecdotal evidence. Now, the benefits of these all well recognised, and widely used. So although I wouldn’t turn to astragalus if I have a headache for the time being, it is more than likely it will offer other benefits than just as a telomerase activator. There is currently already some evidence that astragalus can stimulate parts of the immune system4,5, and can also protect the kidneys from damage, but the evidence for this is very limited for the time being.
Interestingly one of the likely causes of foamy/ bubbly urine is a problem with the kidneys, and although there are no actual clinical trials showing astragalus can help promote kidney health for this particular aliment, we do know it does have positive effects on the kidneys. Maybe we should all listen to traditional medicine more (maybe).
Health risks of astragalus
If it can have beneficial effects on the body it will have the potential to have negative effects too. You might think twice about trying to increase telomerase activity/ stimulate the immune system if it is going to make your hair fall out, so negative effects must be investigated. Fortunately, astragalus teas have been consumed for many years with no recorded ill effects, and studies using small dosages have consistently shown no toxic effects. Studies using extremely high dosages of 2000 mg per kg body weight of cycloastragenol (the active ingredient in astragalus) have also showed no toxic effects6, and you would need to consume many kilos of the astragalus to come close to this dosage. So you are safe to consume astragalus to your hearts content.
There has been concern that because astragalus effects telomere length, it could trigger cancer cell growth, but studies on astragalus and cancer have shown that this is not the case. Rather astragalus has been shown to complement chemotherapy, by improving its performance, or by reducing chemotherapy toxicity7. There are no recorded health risks associated with astragalus, and its toxicology has been tested with some very high dosages, so you don’t have to worry about hair loss or any other possible negative effects from it.
How to get more astragalus in your diet
As much as I love getting all my nutrients from whole food, I have to admit that it isn’t always possible with every nutrient. Its the same story with most herbs – there just isn’t enough recipes which use enough of the herb to make a significant impact on your health. In fact, I’ve never heard of a recipe which includes astragalus, and I’m sure you haven’t either. So, the only real way you can any meaningful amount of astragalus in your diet is with an astragalus supplement.
1. Hector Valenzuela,Clarissa Burguez,Kristin Chikami,Manuel Cruz, and Domenico Rinaldi. (2013). Assessing natural telomerase activators (P4342) . The Journal of Immunology. 193 (5), 144.
2. Bruno Bernardes de Jesus, Kerstin Schneeberger, Elsa Vera, Agueda Tejera, Calvin B. Harley and Maria A. Blasco. (2011). The telomerase activator TA-65 elongates short telomeres and increases health span of adult/old mice without increasing cancer incidence. Aging Cell. 10 (4), 604-621.
3. EFSA. (2011). Consolidated list of Article 13 health claims List of references received by EFSA (part 4). Available: http://www.efsa.europa.eu/en/ndaclaims13/docs/ndaart13ref04.pdf. Last accessed 26th Aug 2014.
4. Chu DT, Wong WL, Mavligit GM. (1988). Immunotherapy with Chinese medicinal herbs. I. Immune restoration of local xenogeneic graft-versus-host reaction in cancer patients by fractionated Astragalus membranaceus in vitro. Journal of Clinical & Laboratory Immunology. 25 (3), 119-123.
5. Bao-Mei Shao, Wen Xua, Hui Dai, Pengfei Tu, Zhongjun Li, Xiao-Ming Gao. (2004). A study on the immune receptors for polysaccharides from the roots of Astragalus membranaceus, a Chinese medicinal herb.Biochemical and Biophysical Research Communications. 320 (4), 1103-1111.
6. Nancy J. Szabo. (2014). Dietary safety of cycloastragenol from Astragalus spp.: Subchronic toxicity and genotoxicity studies. Food and Chemical Toxicology. 64 (n/a), 322-334.
7. Michael McCulloch, Caylie See, Xiao-juan Shu, Michael Broffman, Alan Kramer, Wei-yu Fan, Jin Gao, Whitney Lieb, Kane Shieh and John M. Colford Jr. (2006). Astragalus-Based Chinese Herbs and Platinum-Based Chemotherapy for Advanced Non–Small-Cell Lung Cancer: Meta-Analysis of Randomized Trials . Journal of clinical oncology. 24 (3), 419-430.
Images courtesy of hapal, ajc1 and vintagedept