Raspberry Seeds and Ellagic Acid
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There are a number of foods naturally rich in a powerful antioxidant known as ellagic acid. Good sources of ellagic acid include almonds, black raspberries, peaches, persimmons, plums, pomegranates, red raspberries, walnuts, and wine. The antioxidant properties found in red raspberries are so powerful that raspberry seed extract has been shown in studies to be an excellent, safe preservative, reducing rancidity in food products. (Source)
Ellagic Acid and Cancer
Of course, once a substance has proven to have strong antioxidant properties, scientists look to see what benefits it might have for human health. Thus, in recent years much research has been done on the potential of ellagic acid to prevent cancer. For example, according to research performed at The Hollings Cancer Institute at the University of South Carolina, ellagic acid can inhibit and stop cancer cell division, and induce apoptosis (normal cell death), in a variety of cancers (breast, colon, esophageal, pancreatic, prostate, and skin).
While much of this research was done on cultured human cells, a few human studies have confirmed this anticancer potential of ellagic acid, including one double blind study done on a group of 500 patients with cervical cancer. As well, other human studies have confirmed this anti-cancer potential of raspberry seed extract on lung cancer. (Study). During their research into ellagic acid, the Hollings Institute, under the guidance of Dr. Daniel Nixon, determined that the best and most bioavailable source of ellagic acid was red raspberries.
Many years of research on red raspberries by Dr. Nixon led him to conclude that the amount of red raspberries we need to consume, to attain this anticancer benefit, is about one cup per day. This amount provides us with around 40 mg of ellagitannins, the building block from which we make ellagic acid. (Note this distinction, because there will be more to discuss on the subject of ellagitannins and ellagic acid.)
So, to be precise, when we ingest foods rich in ellagic acid, we are actually ingesting ellagitannins, which will be converted into ellagic acid in our intestines. However, in a clinical study using cells (in vitro) rather than human subjects (in vivo), ellagic acid is used, since cells do not have the ability to convert ellagitannins into ellagic acid. (This will become more relevant as we carry on.)
Not only can ellagitannins slow the growth of cancer cells at low levels, and kill cancer cells (apoptosis) at high intake levels, but they also work as free radical scavengers, binding to cancer-causing agents (tobacco smoke, chemical toxins, etc), and rendering them inactive. As well, ellagitannins further protect us by forbidding carcinogens from binding to our DNA.
But wait, there’s more!
“Ellagitannins exhibit antimicrobial activity against fungi, viruses, and importantly, bacteria, including antibiotic-resistant strains such as methicillin-resistant Staphylococcus aureus.” (Source)
As well, these compounds also have anti-inflammatory and antitumor properties, improve the health of blood vessels, lower cholesterol, and reduce gum recession. Other studies, done overseas, suggest that ellagitannins have a host of other potential benefits. Such benefits include protecting the cardiovascular system, improving wound healing, and preventing birth defects,
As recently as June of 2021, a study titled, “Role of ellagic acid for the prevention and treatment of liver diseases”, was released, indicating that ellagic acid has the potential to reverse liver fibrosis, and prevent the development of liver cancer. (Source) (“Fibrosis is the formation of an abnormally large amount of scar tissue in the liver. It occurs when the liver attempts to repair and replace damaged cells.” Source)
And, in January of this year (2021), it was determined that “ellagic acid is a neuroprotective polyphenol that can protect against demyelination”. (Source) Which means it can be of benefit for all neurological disorders (MS, ALS, Parkinson’s disease, etc).
Ellagitannins vs Ellagic Acid
Just above, when referencing different studies, I went from using the term ellagitannins to ellagic acid. Again, science uses synthesized ellagic acid for cell-based studies, rather than raspberry puree, as was used in the human studies. In the same manner, science uses isolated curcumin instead of whole turmeric extract, which includes the family of curcuminoids. And in the same manner, the whole plant concentrate of turmeric (95% curcuminoids) is ultimately more effective, and safer, than the isolate (95% curcumin). So it is with ellagitannins and ellagic acid.
Certainly, ellagic acid (like curcumin) works effectively at inhibiting cancer growth in cell line studies (in vitro), but studies done with the full range of antioxidant compounds found in ellagitannins, have discovered that some of the other constituents also have powerful therapeutic effects.
According to the USDA Agricultural Research Services: “In pure form, ellagic acid is highly insoluble and biologically unavailable…ellagic acid, as it is biosynthesized in plants, occurs in combination with glucose as ellagitannins. These compounds are quite water soluble and biologically available. This means that relatively small amounts of ellagitannins may be more effective in the human diet than large doses of ellagic acid.”
This concept is backed up by Dr. Nixon, whose human studies are done using whole raspberries containing ellagitannins, rather than isolated ellagic acid. In fact, Dr. Nixon went so far as to state: “What is interesting to note is the superior efficacy of eating red raspberries as opposed to taking the individual phytochemicals in the form of dietary supplement.”
He takes this position because ellagic acid does not naturally occur in plant foods. Plants contain the group of compounds defined as ellagitannins, which are converted to ellagic acid in the digestive tract, through a chemical process. Therefore, when researchers discuss the ellagic content of foods, they are actually referring to the amount of ellagic acid that can be derived from that food.
And, red raspberries have so far been proven to be higher in ellagitannins than other foods containing these compounds, and to have a higher bioavailability. The only other plant that is comparable to red raspberries in ellagitannin content is pomegranate.
One reason other plants are not in the running is that each plant has its own mix of polyphenols. For example, both green tea and grape seed are high in polyphenols (an antioxidant category that ellagic acid belongs to), however because they have a different mix of these components, each has somewhat different therapeutic properties.
Currently, the “Meeker” variety of red raspberry is considered to be the highest source of ellagic acid producing ellagitannins (with pomegranate being a close second).
In his studies, Dr. Nixon gave his patients one cup of red raspberry puree per day, which is enough to obtain a therapeutic dose of ellagitannins. However, outside of summer, this can be difficult and/or expensive to obtain for the average person, so it was fortunate that researchers discovered that the raspberry seeds have a far higher concentration of ellagitannins than the fruit does.
In fact, in a nutritional profile of raspberries put out by the Washington State Red Raspberry Commission, it is established that over 70% of the ellagitannins present in the Meeker red raspberry are found in the seeds. Thus, two grams of red raspberry seed powder provides the therapeutic amount of ellagitannins, 40 mg, which is equal to the amount found in one cup of fresh red raspberries. (Source)
In conclusion, I would like to introduce Provide Smoothie Mix, now containing 1.5 grams of Meeker red raspberry seed powder, per serving. As well, this new version of Provide, designed to support the gut/brain axis, also includes other high antioxidant fruit seed extracts, Lion’s Mane mushroom, Lactospore, and hydrolyzed guar gum, along with plant proteins.