A Complete Guide to Resveratrol Supplements
You may have heard of the heart boosting benefits of red wine – this is mainly due to its high resveratrol content. Beyond being a healthful part of red wine, resveratrol has potential health-boosting capabilities in its own right.
Resveratrol is an antioxidant that is produced by certain plants and can be found in some drinks and foods. Resveratrol supplements have been linked with numerous health benefits including lowering blood pressure, slowing down ageing and protecting the brain.
In this guide to resveratrol supplements, we will be covering the following points:
- What is resveratrol?
- The history of resveratrol
- The benefits of resveratrol supplements
- When is the best time to take resveratrol and how much should you take?
- What are the possible side effects?
- What are the potential interactions and warnings of resveratrol supplements?
What is Resveratrol?
Resveratrol is part of a group of compounds called polyphenols. It is referred to as a polyphenic bioflavonoid antioxidant and it regenerates the body at a cellular level. Polyphenols are micronutrients that give foods their bright colours. Resveratrol is thought to act like an antioxidant, helping to protect you against free radicals and damage that can put the body at a greater risk for things like heart disease and cancer. Free radicals naturally occur in the body but, left unchecked, are associated with ageing and harmful diseases like cancer.
You don’t need to be a wine drinker to receive the benefits of resveratrol. The top dietary sources of resveratrol are peanuts, grapes, blueberries and raspberries. Resveratrol tends to be concentrated mainly on the skin of grapes and berries. These parts of the fruit are involved in the fermentation process of red wine, hence why red wine contains resveratrol.
Other food sources rich in resveratrol include:
- Red grape juice
- Dark chocolate
- Cocoa powder
- Jackfruit skin
The majority of resveratrol supplements are made from an Asian plant called Polygonum cuspidatum, also called Japanese knotweed. The plant is considered an invasive species. In a composition analysis of Japanese knotweed, it was found that it is a great source of resveratrol. It’s also a good source of a few other compounds that are thought to act in a similar way to resveratrol.
So, what’s the difference between resveratrol and trans-resveratrol?
It can sound a bit confusing but there is a difference. Resveratrol is the general product name for supplements that can be sold at varying purity levels. Trans-resveratrol is the active ingredient in resveratrol supplements. Basically, resveratrol supplements can contain different amounts of the active ingredient trans-resveratrol. One brand may contain 5% while another can contain 75%.
Unlike some antioxidants, trans-resveratrol crosses the blood-brain barrier, directly affecting brain cells. This allows for healthy neural support. One study found that resveratrol increased the blood flow to the brain. Increased blood flow means you get more oxygen and nutrients to the brain, supporting healthy cognitive function.
The History of Resveratrol
Resveratrol was first identified in 1939 by a Japanese researcher Dr. Michio Takaoka. It was isolated in the roots of a Japanese plant known as white hellebore. Years later, in 1963, another Japanese scientist isolated resveratrol from Japanese knotweed. The roots of Japanese knotweed had been used in traditional medicine to treat cardiovascular diseases, inflammation and liver diseases. Plants containing resveratrol have been used in traditional medicine for over 2,000 years.
The presence of resveratrol in grapevines wasn’t discovered until 1976. The fact that it’s in wine wasn’t found out until as recently as 1992 by Siemann and Creasy of Cornell University. This realization led to the widespread speculation of wine consumption solving the “French Paradox”. The French Paradox describes the ability the French have to consume a diet rich in saturated fats yet still remain thin.
More recently, scientists from the Harvard Medical School have found that resveratrol can increase the lifespan of yeasts cells and species such as worms and fruit flies. The research on resveratrol and increased lifespan in mammals and humans, however, has been inconclusive so far and therefore largely debated.
The Benefits of Resveratrol Supplements
Resveratrol supplements have been linked to a number of exciting health benefits. Here are nine benefits of resveratrol.
- May Help Lower Blood Pressure
Due to its antioxidant properties, resveratrol may be a promising treatment for high blood pressure. High blood pressure can cause damage to the body and put a person at a higher risk for certain diseases. High blood pressure or hypertension increases the pressure of the blood in your arteries. As a result, hypertension may lead to:
- Heart failure
- Narrow and damaged arteries
- Coronary artery disease
- Damage to the brain and kidneys
- Nerve damage
- Sexual dysfunction
One review carried out in 2015 found that high doses of resveratrol may help to reduce the pressure exerted on artery walls when your heart beats. This type of pressure is referred to as systolic blood pressure and is the top number in blood pressure readings. It’s thought that resveratrol lowers blood pressure by helping the body to produce more nitric oxide. This causes blood vessels to relax.
It’s suggested that more research needs to be carried out before scientists can make a conclusive recommendation about the best dose of resveratrol to get the most benefits in terms of lowering blood pressure. Having said that, the research so far has delivered promising results.
- Protect the Brain
Alzheimer's disease is one of the most common types of dementia. It gets worse over time and affects memory, thought and language. Although younger people can develop dementia or Alzheimer's disease, generally your risk increases as you age. There are over half a million Canadians living with dementia. By 2031, that number is expected to rise 66% up to 937,000.
Several studies have shown that drinking red wine may slow down age-related cognitive decline. This is believed to be partly due to red wines’ resveratrol levels and anti-inflammatory and antioxidant effects. Resveratrol appears to interfere with protein fragments called beta-amyloid. In the Alzheimer’s brain, abnormal levels of beta-amyloid protein clump together, specifically beta-amyloid 42.
Another study suggests that the plant compound resveratrol may help to set off a chain of events that can protect the brain from damage. As a potent antioxidant and inflammatory, more research needs to be carried out to determine how resveratrol may be used to protect the brain.
- May Ease Joint Pain
Over 4.6 million Canadians over the age of 15 have reported having arthritis. That’s the equivalent to one in six. This number is predicted to hit seven million Canadians by 2031. Arthritis is a common problem that leads to joint pain and often a loss of mobility.
Research in test tubes and animals suggest that resveratrol may reduce inflammation and prevent damage to the joints. One study in rabbits found that when injected with resveratrol, the rabbits experienced less damage to their cartilage.
Studies have shown that when taken as a supplement, resveratrol may help to protect cartilage from breaking down. Cartilage breakdown can cause joint pain, which is one of the most common symptoms of arthritis.
- Slow Down Ageing
Resveratrol is a powerful antioxidant that neutralizes free radicals. Free radical damage is caused by lifestyle factors such as excessive drinking, unhealthy eating, smoking and responses to environmental triggers such as pollution and radiation from the sun. There is evidence suggesting resveratrol activates certain genes that help to ward off diseases of ageing.
Consuming foods that are high in phytonutrients and antioxidants has been shown to provide anticarcinogenic and antioxidative benefits that may protect adults from numerous age-related diseases. Oxidative stress breaks down collagen which advances skin ageing. Collagen is what gives your skin its youthful and supple glow. Antioxidants can help to reduce the symptoms of ageing such as fine lines and wrinkles. Antioxidants also help to repair the skin itself and brighten your complexion.
- May Suppress Cancer Cells
It’s estimated that about 206,200 new cancer diagnoses occurred in Canada in 2017. Lung, colorectal, breast, and prostate cancer account for almost half of cancer diagnoses and deaths.
Resveratrol and its cancer-suppressing abilities have been especially studied in test tubes. In both animal and test tube studies, it’s been found that resveratrol may be able to fight several types of cancer cells including colon, gastric, skin, prostate and breast. Resveratrol may help to suppress cancer cells in a few different ways.
Research shows that it may inhibit the growth of cancer cells, stopping them from spreading and replicating throughout the body. Resveratrol may also have the ability to change the gene expression in cancer cells, stopping them from growing. It’s thought that it could also affect hormones, which may inhibit hormone-related cancer from spreading.
- Increase Insulin Sensitivity
Type 2 diabetes is the most common type of diabetes and accounts for almost 90% of all diabetes. There are several risk factors for developing type 2 diabetes, these include:
- Physical inactivity
- Family history of diabetes
- Increasing age
- High blood pressure
Resveratrol has been shown to have several benefits for diabetes, particularly in animal studies. One of the main benefits for diabetes is increasing insulin sensitivity and preventing further complications from diabetes. One explanation for this is that resveratrol is thought to stop an enzyme from turning glucose into sorbitol. Sorbitol is a sugar alcohol and when there is a buildup of it in people with diabetes, it can cause oxidative stress.
- Protect Cardiovascular Health
Heart disease is the second leading cause of death in Canada. Heart disease refers to a buildup of plaque in the heart’s arteries that could result in a heart attack, heart failure or even death. Men are twice as likely to suffer a heart attack than women. Your risk of developing heart disease is increased if you:
- Have high blood pressure
- Don’t exercise regularly
- Have diabetes
- Have a high blood cholesterol level
Due to its anti-inflammatory properties, resveratrol has been shown to protect against atherosclerosis and coronary heart disease. Atherosclerosis is a serious health condition where the arteries become clogged with fatty substances known as plaques or atheroma.
- May Prevent Obesity
Obesity is a global pandemic. Worldwide obesity has nearly tripled since 1975 according to the World Health Organization. With obesity comes a number of health risks. It can result in harmful conditions such as:
- Type 2 diabetes
- Coronary heart disease
- Depression and low-self-esteem
Evidence from animal studies showed that resveratrol helped to prevent fat storage and regulated insulin levels in rodents on a high-fat diet. Other research suggests that resveratrol may help to reduce body weight in obese animals. This is thought to happen due to the SIRT1 gene being activated. This gene is believed to protect the body from obesity. It’s not completely clear how resveratrol will affect obesity in humans however initial research shows that it could have massive potential in this area.
- May Encourage Normal Estrogen Levels
Consuming resveratrol may be beneficial to women, especially older women. At menopause, estrogen levels naturally decline. Some research suggests that resveratrol could help stabilize estrogen levels as well as other hormones.
One small study of postmenopausal women taking resveratrol daily for 12 weeks showed improvements in estrogen metabolism. The supplement also promoted normal levels of SHGB (sex hormone-binding globulin). The role of SHGB is to help the body make better use of the hormones already present. Resveratrol may support hormone balance, therefore, helping heart and bone health.
Another study found that resveratrol can help correct hormone imbalances in women with polycystic ovarian syndrome (PCOS). PCOS is a hormonal disorder. Women with PCOS may experience infrequent or prolonged periods, excess male hormone levels and small collections of fluids in the ovaries. PCOS is one of the most common causes of infertility and affects an estimated 6% to 10% of the female population. The supplement appears to lower testosterone levels in women with PCOS according to evidence published in the Journal of Clinical Endocrinology & Metabolism.
When is the Best Time to Take Resveratrol and How Much Should You Take?
It’s suggested that the best time to take antioxidants such as resveratrol or astaxanthin is with a fatty meal because they are fat soluble. If the dosage calls for twice a day then aim to take the supplement in the morning and evening with a meal if possible.
Most resveratrol supplements contain 50-500mg of resveratrol. This differs from brand to brand. Some products can contain higher doses, up to around 1,200mg. Although clinical studies in humans are somewhat limited, the dose of resveratrol taken daily ranges from 150-500mg in clinical studies. For boosting weight loss, it’s been found that 150 mg/day for a minimum of 30 days is beneficial. During studies, higher doses have been needed to have an effect on brain circulation and hormone levels.
The dosage can vary massively from brand to brand so always read the instructions carefully. A higher dose may need to be taken only once a day whereas a lower dose may need to be taken twice daily.
What are the Possible Side Effects?
Generally, resveratrol is considered safe and well-tolerated by the majority of adults. It’s suggested that resveratrol taken up to 500mg/day is tolerated in healthy adults in clinical studies. Although rare, when taken as a supplement, some people may experience mild to moderate gastrointestinal symptoms and diarrhea. Other reported side effects include cramping, decreased appetite and pain in the joints.
Resveratrol has been shown to have both estrogen agonist and estrogen antagonist effects in test tube studies. Estrogen agonists act to promote the effects of estrogen, whereas estrogen antagonists work to block the effects of the hormone by binding to the receptor sites. The estrogen hormone has the potential to aggravate estrogen-dependent tumours. These types of tumours have estrogen receptors that need the hormone to be able to grow.
No major risks or severe side effects have been discovered in studies. However, it’s important to understand that no conclusive recommendations have been made about the amount of resveratrol a person should take to achieve health benefits.
Resveratrol may reduce the absorption of iron in the body, potentially worsening anemia. Resveratrol signals certain genes involved in iron metabolism, which can reduce iron absorption. However, this same resveratrol effect on iron metabolism may be beneficial in the case of iron overload.
What are the Potential Interactions and Warnings of Resveratrol Supplements?
Resveratrol supplements may interact with certain medications. Here are known interactions of the supplement and its effects.
- Blood thinners - high doses of resveratrol have been shown to stop blood from clotting in test tubes. Therefore, it’s possible it could increase bleeding and bruising in people who take blood thinners such as heparin or warfarin.
- Certain blood pressure, anxiety and immunosuppressant medications - resveratrol may block certain enzymes that help to remove particular compounds from the body. This means there could be a buildup of some medications to an unsafe level.
- Medications changed by the liver - some medications are altered and broken down by the liver. Resveratrol may decrease the speed at which the liver breaks these medicines down. This may increase the side effects and effects of the medication. Medications that are changed by the liver include chlorzoxazone and bufuralol.
This list of medications is not exhaustive. If you’re taking medication, always consult your health provider before taking any supplements.
If you’re considering taking resveratrol supplements, there are warnings and cautions in place for some health conditions. If you have any of the following, you should avoid taking the supplement.
- Pregnant or breastfeeding - research into human pregnancy and resveratrol is limited so it’s best to stay on the safe side and avoid it.
- Blood condition - if you have a blood condition or are taking blood thinners, you should avoid consuming resveratrol supplements.
- Hormone-sensitive conditions - as resveratrol may impact estrogen and hormone levels, if you are suffering from an illness such as breast cancer or ovarian cancer which is affected by hormones, then you should avoid resveratrol.
- Resveratrol allergy - if you are allergic to any of the ingredients in the resveratrol supplement, do not use them.
- Surgery - resveratrol may increase the risk of bleeding after surgery. It’s advised to avoid taking it for at least two weeks before surgery.
Resveratrol is a potent antioxidant with great potential. Research suggests that the polyphenol antioxidant has many benefits and could even protect against cellular damage. With anti-ageing properties, it’s a powerful ally for brain and heart health. As more research comes to light, the potential therapeutic and preventative abilities of resveratrol will be made even clearer.