Hoping to expand your nutrition knowledge beyond the basics, or diving into the world of antioxidants? If so, it won’t be long before you find yourself stumbling upon resveratrol. Resveratrol is a polyphenol, a class of micronutrients with antioxidant function.
Antioxidants reduce the cellular damage created by free radicals, unstable molecules involved in the process of systemic inflammation that increases the risk for cancer, heart disease, and other inflammatory conditions. While consumption of resveratrol has been shown to reduce the risk for a number of significant and life-threatening health conditions, the role of resveratrol supplementation poses new concerns around resveratrol side effects, efficacy, and consumer safety.
What is Resveratrol used for?
Resveratrol can be consumed via a dietary supplement, or naturally through whole food sources. Found plentifully and in high doses in grapes, wine, grape juice, cocoa, blueberries, bilberries, cranberries, and peanuts, the bioavailability of whole food sources of resveratrol is typically higher than the bioavailability of resveratrol consumed in supplement form.
Resveratrol has been studied for its effect in the prevention and treatment of various diseases and conditions, including, but not limited to cancer, heart disease, diabetes, and neurodegenerative conditions, such as Alzheimer’s disease, Parkinson’s disease, and dementia. It has also been linked to weight loss.
However, it’s important to note that studies surrounding resveratrol and disease prevention are ongoing, and no firm conclusions have been made. While studies have shown some beneficial impact on measures of cardiovascular disease risk, the rate of cognitive decline, and cancer metastasis, many of these studies were in animal or in vitro models.
The ways to consume resveratrol
Resveratrol can be consumed in either supplement or whole food form. It is generally agreed upon that consuming resveratrol in whole food forms is the safest and most advantageous option available currently, as supplements are not regulated by the Food and Drug Administration, leaving risk for low product quality or unspecified ingredients.
Is resveratrol safe?
Resveratrol is generally recognized as safe, save for those who are already taking other supplements or medications, as resveratrol has been shown to interact with other prescription medications and dietary supplements. This is especially important for those taking blood thinners, such as warfarin and/or coumadin, as resveratrol supplementation may increase the risk for bleeding.
Resveratrol side effects from supplementation
The effects of resveratrol are as wide and varied as the health benefits of resveratrol. Below are some of the effects of resveratrol:
Acne
Like many other drugs and supplements, resveratrol may increase the risk for acne, or increase the severity of existing acne. While acne is not a common side effect associated with consumption of resveratrol supplements, a number of consumers have reported increased acne incidence with supplementation.
Surgery
Resveratrol acts as an anticoagulant, increasing the risk of bleeding. Given the increased risk for bleeding that occurs with resveratrol supplementation, those who have recently undergone surgery (or those planning on undergoing surgery) should avoid resveratrol supplementation, unless their personal physician or surgeon recommends otherwise.
The time between surgery and cessation of supplementation should also be discussed with a care team prior to any procedure, as it may take a few weeks for the anticoagulation effect to not pose a major bleeding risk.
Insomnia
While the mechanism of action is not understood, some patients taking resveratrol supplements have reported insomnia-like sleep disturbances, including difficulty falling or staying asleep. For this reason, those with a history of sleep disturbances — or those who take medication for insomnia — should not take resveratrol supplements.
Drug Interactions
As is the case for any dietary supplement, regardless of type, resveratrol has the potential to interact with other prescription medications, over the counter drugs, and dietary supplements. For this reason, consumers should always consult their physician before beginning supplementation or self-prescribing a supplement.
Resveratrol can interact negatively with a number of medications, most notable medications with anticoagulant (blood thinning) effects. For this reason, patients taking medications for blood pressure, stroke or cardiovascular disease risk, and clotting should avoid resveratrol supplements unless prescribed by a personal physician.
Additionally, patients with a history or increased risk for liver disease should not take resveratrol supplements, or should talk to their doctor before beginning a regimen of supplementation.
Studies have shown a significant risk for interactions with medications processed by the liver. Resveratrol consumption should be avoided for those taking chlorzoxazone, theophylline, bufuralol, or other medications processed by the liver. If you are not sure whether medications you are currently taking are processed by the liver, contact your physician before beginning supplementation.
Estrogenic Effects
The chemical structure of resveratrol is very similar to synthetic estrogen agonist. For this reason, some scientists theorize that resveratrol may bind to estrogen receptors and elicit a similar impact as endogenous estrogens. However, studies have shown that resveratrol may act as either an agonist or an antagonist, meaning that resveratrol may act to promote estrogenic activities, or on the contrary counteract them.
The determination of the action, agonist vs antagonist, largely comes down to cell type, the form of estrogen receptor, and the presence of endogenous naturally occurring estrogen.
Because little is known regarding the effect of resveratrol on estrogen-sensitive disease conditions, women with a history or increased risk for breast cancer, ovarian cancer, and uterine cancers should avoid taking resveratrol supplements.
Stomach Troubles
As with any dietary supplement, resveratrol supplementation comes with an increased risk for an upset stomach. This may include nausea, cramping, pain constipation, diarrhea, gas, bloating, or urgency. Gastrointestinal problems tend to be worse when consuming supplements on an empty stomach.
For this reason, always avoid taking resveratrol on an empty stomach (if you do decide to begin supplementation). To avoid stomach upset altogether, favor whole food sources of resveratrol.
Arthritis Pain
Arthritis pain is one of many age-related diseases and while joint pain is not a common symptom associated with the consumption of resveratrol supplements, consumers at an increased risk for joint pain, such as those with arthritis, may experience an increase in pain symptoms while taking resveratrol. Patients have reported increases in pain in muscles, tendons, and joints while taking resveratrol supplements, with pain manifesting in the Achilles tendons, hands, and shoulders.
Jittery Feelings
While sensations of shakiness or a jittery feeling is not a common side effect of resveratrol supplementation, it has been noted in a small number of cases. This may be due to tainted supplements, given that supplements are not regulated by the Food and Drug Administration.
For this reason, many supplements contain unspecified ingredients that may be to blame for sensations of shakiness, nervousness, anxiety, or an otherwise jittery feeling. If you experience these symptoms while taking any drug or supplement, contact your physician immediately.
Flu-Like Symptoms
The gastrointestinal upset experienced by some patients while taking resveratrol supplements may cause flu-like sensations of symptoms. If you experience these symptoms, contact your doctor if the supplements were prescribed to you, or stop supplementation immediately if you self-prescribed. If your symptoms cease after you stop taking resveratrol, the supplements were likely to blame.
Blood in the Urine
Given that resveratrol functions as an anticoagulant, a small number of patients have reported blood in their urine after consuming resveratrol supplements. If this occurs, contact your doctor immediately.
Resveratrol foods: Avoiding side effects the natural way
Given the litany of side effects that may occur with resveratrol supplementation, and given the theoretically low bioavailability of resveratrol supplements, consuming resveratrol in natural food forms is likely of highest benefit for consumers interested in consuming resveratrol in an effort to reap its antioxidant properties and for its health benefits.
Itadori tea
Far less common than green or black teas, many consumers have never even heard of itadori tea. Itadori tea, also known as Japanese Knotweed, is a perennial, herbaceous shrub that grows very aggressively, leading to its classification as an invasive species. Itadori teas are often used for their resveratrol content, although research surrounding the consumption of Japanese Knotweed is ongoing.
Red grapes
Interestingly, resveratrol occurs only in the skin of red grapes. The amount of resveratrol and free radicals present in any one bunch of grapes varies widely, depending on geographic origin, farming practices, and grape skin exposure to environmental fungus and invasive pests.
While red wine is typically discussed with high regards for its resveratrol content, other polyphenols found in red wine are much more abundant than resveratrol. Additionally, the research surrounding wine consumption and health is still evolving and is highly complex.
While research has shown that moderate drinking is associated with a reduction in cardiovascular disease risk, it is also associated with an increased for many types of cancer, including cancers of the head, neck, esophagus, liver, breast, colon, and rectum.
Grape juice has also shown to have the effects of resveratrol one gets through drinking wine, without the alcohol after effect.
Blueberries
Common and well-loved, blueberries have been regaled for their antioxidant content for a number of years, resveratrol included. Blueberries are not the only berries containing resveratrol: cranberries and bilberries are also good candidates.
However, the widespread availability of blueberries makes them a great whole food source for consumers hoping to include resveratrol foods on their trip to the grocery store. It should also be noted that cooking appears to reduce the resveratrol content of blueberries.
Dark chocolate
Cocoa and dark chocolate are a good source of antioxidants, resveratrol included. Dark chocolate contains two to three times as much antioxidant content as milk chocolate thanks to its highly condensed nature. While studies have shown a beneficial impact on markers of cardiovascular health with consumption of high-quality dark chocolate and cocoa, research in this area is ongoing.
Also keep in mind that many chocolate products are also high in sugar, fat, and calories, potentially negating the beneficial impact of resveratrol content. Whenever purchasing or consuming a chocolate product, always look for high cocoa content and minimal add-ins.
Peanuts
Once enjoying a ranking as the United State’s most consumed nut, peanuts have now become somewhat threatened by almonds, as peanuts have now been surpassed by almonds in growth rate. However, peanut still remains widely popular, with little likelihood of cultivation and consumption slowing down anytime soon. Peanuts are a good source of resveratrol and healthy unsaturated fats. Studies have shown that consuming 1.5 oz of peanuts each day may help reduce the risk for heart disease.
Peanut butter
Just as peanuts contain resveratrol, so too does peanut butter. The condensed nature of peanut butter actually makes it higher in resveratrol content than peanuts. However, the pureeing or grinding process also makes peanut butter much higher in calories, which may be problematic for weight management. Many peanut butters also contain partially hydrogenated oils, increasing the risk for high blood pressure, heart disease, and stroke. For this reason, always purchase nut butter that does not contain hydrogenated or partially hydrogenated oils.
Pistachios
While perhaps not as well-loved as almonds, peanuts, or cashews, pistachios are a good source of resveratrol. Additionally, the peel and eat nature of pistachios requires consumers to slow down while eating them, which has shown to be of benefit to weight management in certain instances. Other studies have found a significant correlation between nut consumption and longevity. When consumed in moderation, nuts play a vital role in heart health, especially when nuts replace sources of saturated and trans fat in the diet.
Resveratrol: What we know and what we don’t
Resveratrol antioxidant properties are likely of benefit to consumers. However, the role of resveratrol supplements is not well understood, and the lack of supplement regulation by the Food and Drug Administration is concerning, as it increases the risk for unspecified ingredient content and subsequent drug interactions or negative side effects. Even in the absence of unspecified ingredients, poor product quality or impurities may be of concern.
Additionally, certain consumers should not take resveratrol supplements, including those taking other medications or dietary supplements, those at an increased risk for bleeding, and women who are pregnant or may become pregnant. Although supplementation may not be a good route for the majority of consumers, consumption of resveratrol in natural form poses little to no risk and is likely of benefit. Whole foods containing resveratrol contain other beneficial micronutrients and antioxidants that also serve to promote general health and cellular function.
For this reason, consumers interested in resveratrol antioxidant properties should turn to whole food sources before considering supplements, and should always speak with their individual physician before purchasing or consuming resveratrol supplements.