OPC: Powerful Antioxidant or Humbug?
The world of dietary supplements comes in many colors: for commercially understandable reasons, companies like to discover miracle drugs that supposedly improve your health in fantastic ways. OPC grape seed extract is one of the natural substances that are supposed to act like a fountain of youth. Can OPC really do that and who needs OPC? Inform yourself comprehensively!
OPC: what do these letters mean?
The letters OPC stand for oligomeric proanthocyanidins. The term oligomer describes a large molecule that consists of several identical or chemically similar building blocks. Proanthocyanidins are a group of condensed flavan-3-ols found in many plants, such as apples, most pine trees, cinnamon, aronia berries and grape seeds and grape skins. Berries and tea Tea and other plants also contain these flavonoids. Cocoa beans contain the highest concentrations (1).
OPC: What is it?
OPC as a dietary supplement is usually made from grape seeds. Grape seeds are a waste product in wine production and are therefore a cheap raw material, but they are rich in oligomeric proanthocyanidins and other polyphenols (2). OPC grape seed extract capsules are often fortified with resveratrol, a polyphenol also found in grapes (3).
These secondary plant active ingredients are said to have a strong antioxidant effect and to be able to destroy bacteria and viruses. In addition, they are reported to reduce inflammation, increase blood flow, strengthen blood vessels, and promote antioxidant enzyme reactions (4).
Proanthocyanidins belong to the group of tannins, which in turn are flavanols, a member of the flavonoid family and the parent polyphenols, secondary plant compounds. Tannins are phytonutrients that protect plants. They have an astringent and drying effect and thus remove the breeding ground for bacteria. In humans, they have a beneficial effect on wound healing. Traditional medicinal plants are often excellent sources of these phytochemicals (5).
OPC: who discovered it?
OPC is one of the first plant active ingredients to be discovered and scientifically studied decades ago. The Hungarian Nobel Prize winner Albert von Szent-Györgyi Nagyrápolt discovered flavonoids back in the 1930s.
The French physician and microbiologist Jacques Masquelier was the first scientist to isolate OPC in 1947 — not from grape seeds, but from the red skin of peanuts. He wanted to know whether the superfluous membranes could be used as animal feed. In animal experiments, he found out that the peanut skins can heal vein diseases. He then isolated OPC as the substance responsible for the healing effect.
Since its discovery, OPC has been the subject of numerous studies. PubMed, the US medical library, provides around 1,000 studies when searching for grape seed extract, Dutch scientists found in a study published in 2017 (6). In a way, the research results reflect the advances in science since 1947.
In addition, the researchers emphasize the difficulties in scientifically proving concrete claims for products made from fruit. On the one hand, the product, in this case OPC grape seed extract, should have consistent ingredients. However, the ingredients of every natural product are subject to fluctuations. Just think of the importance of the vintage for the taste of wine. However, a study published in 2019 (7) showed that grape seeds of different varieties contain a lot of OPC.
In addition, according to the Dutch study, the direct cause-and-effect relationship should be supported by human studies. This is where the European Food Safety Authority (EFSA) criticized OPC grape seed extract. In 2009, it rejected claims that OPC as a dietary supplement could be labeled as lowering cholesterol (8) and improving circulation in venous insufficiency (9). However, the EFSA only considered older studies in its assessment (10).
This negative assessment of OPC by EFSA was reflected in the attitude of the German consumer advice center, which is supported by the Federal Ministry of Food and Agriculture. Right at the beginning of the text on OPC and resveratrol (11) it is boldly claimed that research on resveratrol, OPC or grape extracts is still in its infancy. Many advertising statements are not sufficiently scientifically proven.
The fact is, however, that scientist Masquelier began researching OPC back in 1947. He was so convinced of the effect that he founded a company for the production of OPC. He spent the rest of his life researching its effects.
It’s also a fact that in the recent past, numerous studies on antioxidants, including grape seed extract, have been conducted in humans. Admittedly, the number of participants was mostly small. Nevertheless, a certain significance cannot be denied.
On the other hand, the source of the text from the consumer advice center appears somewhat thin. A total of only four sources are given, two of which are the European Commission’s position on resveratrol.
An Italian study (12) that caused a stir in 2014 is also mentioned. Accordingly, resveratrol in red wine has no life-prolonging effect. Furthermore, the consumer center quotes the German medical journal that interprets the Italian study. The February 2018 text completely disregards recent studies on OPC and resveratrol. It also ignores the fact that resveratrol is found in many foods (13).
Why OPC Grape Seed Extract?
A healthy diet with plenty of fruit and vegetables provides the body with numerous nutrients. However, those suffering from a chronic disease can definitely benefit from dietary supplements. Autoimmune diseases such as multiple sclerosis, Hashimoto’s thyroiditis or rheumatoid arthritis burden the body with oxidative stress (14) (15) (16).
OPC: Powerful antioxidant
Determining the effect of OPC grape seed extract on free radicals in the human body is almost impossible. How can you prove with certainty what exact effect a particular substance has? This is only possible with large-scale studies.
A US study (17) was published in 2000. Scientists studied various living human cells and conducted animal experiments. The result: the bioavailability of grape seed extract is very high. OPC therefore offers significantly better protection against free radicals than vitamins C, E and beta-carotene.
The antioxidant effect of grape seed extract was confirmed by a 2013 study (18) in human cells and a 2015 study (19) using animal experiments. Apparently, OPC promotes the transcription factor NRF2. This protein acts as a molecular switch that protects cells from stress and is active in wound healing.
Can lower blood pressure
High blood pressure is one of the most widespread life-threatening complaints worldwide. Excessively high blood pressure means for the body: vascular walls have to endure forces that they are not designed for. The heart also has to work hard. Over time, high blood pressure overloads the heart, other organs and blood vessels. In addition, the risk of cardiovascular diseases as well as heart attacks and strokes increases enormously.
A meta-study by Chinese scientists published in 2016 evaluated 12 studies with a total of 816 participants (20). Accordingly, between 100 mg and 800 mg of OPC per day effectively improves high blood pressure. However, it took between 8 and 16 weeks for this effect to be fully felt.
US researchers conducted a randomized controlled study in the same year (21). In this study, 36 participants received 300 mg of grape seed extract daily. This dosage was also able to reduce high blood pressure after 6 weeks.
Inhibits inflammation
Many chronic diseases share a common trait: they are rooted in inflammation (22). The immune system responds to any disturbance by inflaming the tissue around the disruptor. In the case of a temporary illness, the inflammation disappears again. If the balance remains disturbed, inflammation becomes chronic. Those affected often do not even notice that there are numerous sources of inflammation in their body.
Fighting inflammation is a typical property of antioxidants. Inflammatory processes burden the entire metabolism with oxidative stress. The brain is also sensitive to this type of stress. Experts around the world now suspect that oxidative stress not only plays a role in depression and anxiety, but also in mental illnesses such as bipolar disorder and schizophrenia (23).
Positive effect on the psyche
The relief of the immune system through the anti-inflammatory effect of plant substances is obviously also noticeable in the psyche. British scientists investigated the effect of flavonoids, including OPC, on mood in a large-scale study evaluating a total of 82,643 cases in elderly women (24). Accordingly, the consumption of flavonoids can lead to a lower susceptibility to depression.
A group of international researchers who published a study on the subject in 2017 came to a similar conclusion. They consider flavonoids to be promising candidates for the treatment of depression and anxiety (25). An animal experiment also showed that grape powder improves brain function in post-traumatic stress disorder (26).
Counteracts neurodegenerative diseases
The antioxidant effects of OPC can help prevent neurodegenerative diseases such as Alzheimer’s or dementia (27). In a 3-month study of 111 elderly people, OPC was shown to improve concentration and memory (28). In addition, these active ingredients can counteract beta-amyloid peptides. As a component of senile plaques, these substances are considered important factors in Alzheimer’s disease and dementia (29).
Alleviates chronic inflammatory bowel diseases
The anti-inflammatory effect of grape seed extract in chronic inflammatory bowel diseases has been shown in several animal experiments. Chinese scientists published a study in rats in 2013 (30). Accordingly, OPC alleviates the symptoms and also improves the composition of the intestinal flora.
Apparently, grape seed extract interferes with the protein Claudin-2, which triggers diarrhea in Crohn’s disease and ulcerative colitis (31–32). Additionally, grape seed extract appears to inhibit pro-inflammatory cytokines in the gut (33).
In a 2020 study, Spanish researchers showed that OPC from grape seeds strengthens the barrier function of the intestinal wall (34). In addition, the scientists consider it proven that these active ingredients effectively reduce inflammation in the digestive system.
Helps with joint problems
Thanks to the anti-inflammatory effect, OPC and grape seed extract can also relieve the symptoms of joint problems — regardless of whether it is an autoimmune disease such as rheumatoid arthritis or osteoarthritis caused by wear and tear or accidents (35–36).
Accordingly, OPC are apparently able to effectively reduce inflammation in joints through various signaling pathways. It may even work to protect bone mass from the effects of rheumatoid arthritis
Protects the liver
The liver is the organ that protects our body from toxins of all kinds. Grape seed extract, in turn, can help protect the liver from damage from toxins. An important biomarker for this is the enzyme alanine aminotransferase (37). If an elevated level of this enzyme is detected, the liver is probably damaged.
Grape seed extract with OPC even has a positive effect on fatty liver. This is the most common liver disease in Germany, which does not only occur with alcoholism. In patients with fatty liver, after 3 months of taking grape seed extract, the enzyme alanine aminotransferases was shown to decrease by almost half (38).
Strengthens kidney function
The kidneys often suffer from chronic stress. The adrenal glands are particularly challenged during stress because they produce the messenger substances adrenaline, noradrenaline and cortisol. The body needs these signal substances for the stress reaction. Over time, this can affect kidney function.
In a study published in 2016, Tunisian scientists showed that OPC can have a beneficial effect on kidney function (39). Patients with chronic kidney disease received 2 grams of grape seed extract for 6 months. It was found that the kidneys were able to filter urine better under this influence.
Improves cholesterol levels
Conventional drugs improve cholesterol levels, but often have serious side effects. OPCs from grape seed extract can also balance cholesterol levels without the price of unwanted side effects. This is the conclusion reached by US researchers in a study published in 2000 (40).
Promotes insulin sensitivity
In obese patients — with and without existing diabetes — insulin works increasingly poorly. The body has to produce more and more insulin until insulin resistance occurs. This is a typical side effect of the metabolic syndrome.
OPC can help counteract this. British researchers found that grape seed extract improved insulin sensitivity in obese patients with type 2 diabetes (41). An animal experiment in 2014 yielded similar results (42).
Helps with periodontal disease
OPC also develop their anti-inflammatory effect in the oral mucosa. In this way, these active ingredients can help to get periodontal disease under control (43). In Germany, almost every second person suffers from periodontal disease. Along with tooth decay, gum disease is the most common reason for tooth loss. Periodontosis is particularly noticeable in implants.
Prevents cell damage from exercise
Intensive sport puts enormous strain on the body and can lead to damage at the cellular level. OPCs may help protect cell walls during heavy muscle exertion (44).
Accelerates wound healing
The antioxidant effect of OPC even has a beneficial effect on wound healing. This was shown in a study in which a cream with OPC accelerated the healing of surgical wounds by almost half (45). In addition, OPC can improve the elasticity of the skin and strengthen the skin’s protective barrier (46).
Natural blood thinner
OPC acts as a natural blood thinner because it inhibits platelet aggregation (47–48). This is the sticking together of platelets to seal wounds. This effect is definitely desirable for smokers, because nicotine promotes the development of thrombosis. For this reason, however, one should not combine blood-thinning drugs such as warfarin with OPC.
How to take OPC?
OPC works best if you take the capsules on an empty stomach in the morning. If your stomach is sensitive to it, you can also take OPC between meals. Ideally, allow at least an hour after a meal.
Under no circumstances should you take grape seed extract supplements together with dairy products or other foods that contain a lot of protein. OPC tend to associate with protein. If this happens, your body can no longer utilize the active ingredients.
Grape seed extract may adversely affect the absorption of iron (49). People with special needs for iron such as pregnant women, children and adolescents should pay attention to this when taking OPC.
Sources:
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