Level of actives varies widely among saw palmetto products, researchers find
Saw palmetto as an ingredient has been used for decades in cases of benign prostate hyperplasia. The ingredient has been offered in various forms, ranging from ground green berries, to extracts of the ripened berry to tinctures and even teas. But the amount of active ingredients in each form varies widely.
Wide range of actives
This could mean that large numbers of Americans are using products to ameliorate BPH that do not have enough of the active ingredients to have an effect. The researchs said 1.7 million people reported using saw palmetto in 2007, and in 2011, $18 million worth of saw palmetto products were sold in the US.
So far as is known, saw palmetto works by inhibiting 5 alpha reductase, the enzyme that converts testosterone into the more potent androgen dihydrotestoterone. It is believed that the botanical’s fatty acid and phytosterol content is responsible for this.
Saw palmetto has shown some promising results in studies, but has also shown equiovocal results in some large studies. The researchers raised the question of whether the quality of the saw palmetto used in those studies was uniform.
In the study, researchers Kavitha Penugonda and Brian L. Lindshield from Kansas State University looked at 20 commercially available saw palmetto products and analyzed them for the levels of these actives. These were divied among liquids, powders, dried berries (one of which was called a ‘powdered betty’ product) and tinctures.
Their results were unequivocal: Liquid products had an overwhelmingly greater amount of fatty acids, with a mean content of 90.9% on a mg/g basis, with Doctor’s Best the highest at 94.1%. Powders had a mean of only 18%, with GNC’s Saw Palmetto Formula the weakest at 6.9%. Dried berry products had a mean of 12.6%, and tinctures had the lowest amount, with a mean of 4.6%. Measurements of phytosterol content showed a similar large difference between the various product categories.
False advertising?
“There are several companies that sell to the mass market that sell saw palmetto in capsules and what that is is saw palmetto green berry powder. You have a concentration of fatty acids and phytosterols that is very low,” Rudi Moerck, PhD, CEO of Valensa International told NutraIngredients-USA. Valensa sells a CO2 extracted oil ingredient called USPlus.
“Basically it is a scandal and false advertising when people claim that this powder they have in these capsules can have any sort of effect on prostate health, because the amount of the actives is only about one tenth of what it should be. It winds up giving reputable products a bad name because people try these powders and they don’t work,” he said.
The Kansas State researchers said the efficaciousness of the various product categories has not been measured one against the other and will be the subject of future research.
“It’s certainly frustrating when we hear the reports of that, when we hear about the general pixie dusting of products,” said Cara Welch, PhD, senior vice president for scientific and regulatory affairs for the Natural Products Association. “You could go as far as saying that it is economically motivated adulteration.”
“There are a number of clinical studies available on reputable products containing saw palmetto extracts. Those preparations, or preparations which are phytoequivalent, should be preferably used, independent of their fatty acid content,” said Stefan Gafner, PhD, chief science officer of the American Botanical Council.
Questions of validation
Gafner did note that there were a few holes in the Nutrient paper, which could cast some doubt on the relative values if not the ultimate conclusion. Gafner noted, as did the authors, that some of the additional ingredients, such as pumpkin seed oil, in some of the products skewed the results a bit. And he said he was unsurprised at the low levels of fatty acids found in the tinctures.
“From my own experience with glycerin-water mixtures, this solvent system does not extract the lipophilic constituents of saw palmetto,” he said.
“The authors used an older method for the fatty acids from 1988 and there is no indication that they have validated their fatty acid and phytosterol methods. Even if the methods are appropriate, the lack of validation is a missing piece in their work. I also believe it would have been more meaningful to relate their results to daily intake rather than mg/g of dry weight,” he said.
Source: Nutrients
2013, Volume 5, Number 10, Pages 3617-3622; doi:10.3390/nu5093617
“Fatty Acid and Phytosterol Content of Commerical Saw Palmetto Supplements”
Authors: K. Penugonda and B. Lindshield.
