Artichoke leaves – metabolic and glycemic response
Lots of brands advertise supplements that contain the above to reduce the glycemic response after meals as well as improve metabolic issues, but is there any research to support this?
There is a significant amount of research on artichoke leaf extract (ALE) from the species Cynara scolymus (as opposed to directly feeding artichoke leaves). One effect in people is that it may stimulate bile secretion. In a meta-analysis, ALE was found to reduce the activities of enzymes associated with liver damage, again in people. ALE has also been shown to reduce cholesterol and LDL cholesterol. Studies in isolated cells and some laboratory animals has shown that ALE may lower blood glucose. There only appears to be one study in people published in 2020 https://pubmed.ncbi.nlm.nih.gov/33126534/. Obese adults with impaired glucose tolerance were given a placebo of 1g ALE for 8 weeks. The ALE group experienced a 13% improvement in fasting glycemic response, some reduction in insulin resistance and a reduction in bodyfat.
Artichoke from the species Cyanra scolymus does appear on the Feed Materials Register “Aerial parts of Cynara scolymus L. (artichoke), crushed, filtrated, spray-dried.”
I was able to find several published papers on feeding Cynara scolymus to horses. In one study, Cynara scolymus and Silybum marianum were fed to horses to alleviate the liver toxicity induced when treating horses with piroplasmosis with imidocarb dipropionate. https://pubmed.ncbi.nlm.nih.gov/33178437/ The authors only studied 10 horses, split into 2 groups of 5. They concluded “C scolymus and S marianum supplements resulted in beneficial hepatoprotective effects in horses treated with imidocarb dipropionate.” However, obviously, it is not possible to infer which plant had the most effect. The supplement contained 11.5 g of C scolymus extract and 96g of milk thistle extract (Silybum marianum).
Other studies in horses have used the Jerusalem artichoke which is a very different species – Helianthus tuberosus. This is considered to be a prebiotic and is also on the Feed Materials Register.
One study published in 2017 studied glucose and insulin responses to feeding Jerusalem Artichokes (JA) for 3 weeks. 939g of JA meal did not change the peak glucose or insulin nor the area under the curve (AUC). There was a tendency for glucose and insulin to decline more rapidly after JA. So this study is not particularly convincing for JA improving glucose regulation in mares with normal body condition score. The result may of course have been different in obese of insulin insensitive horses. https://pubmed.ncbi.nlm.nih.gov/28627061/
A more recent study in horses showed that JA feeding (as a prebiotic) increased the rate of disappearance of glucose, fructose, sucrose and fructans from the stomach but the authors did not assess blood glucose or insulin responses. https://pubmed.ncbi.nlm.nih.gov/34607684/
One study in obese people showed improvements in glucose and insulin regulation with Cynara scolymus. We currently have no evidence that artichoke (Cynara scolymus) or Jerusalem artichoke (Helianthus tuberosus) will improve glucose and insulin regulation in horses or ponies, obese or normal body condition.