New research suggests that occasional wine consumption as part of the Mediterranean diet may benefit heart health. The Mediterranean diet, rooted in the traditional cuisines of countries bordering the Mediterranean Sea, is often touted for its health benefits, particularly in reducing the risk of cardiovascular disease. However, the role of red wine, a common component of this diet, has been a subject of ongoing debate. While some studies suggest a protective effect, others highlight the potential harms of alcohol consumption.
The Mediterranean Diet: A Foundation for Heart Health
The Mediterranean diet emphasizes plant-based foods such as fruits, vegetables, whole grains, legumes, and nuts. Moderate amounts of dairy, poultry, eggs, and seafood are also included. Unsaturated fats, particularly olive oil and those found in fish, are key components. This dietary pattern provides adequate intakes of total fat and long-chain polyunsaturated fatty acids, dietary fiber, antioxidant vitamins, carotenoids, and polyphenols, as well as a balanced n-6/n-3 ratio of essential fatty acids and low amounts of saturated fatty acids (SFA).
The Mediterranean diet is not a rigid, uniform nutritional model but rather a collection of diverse dietary habits traditionally followed by countries around the Mediterranean basin. Despite their heterogeneity, some common patterns are observed across these countries. These patterns include a high consumption of plant products such as fruits, vegetables, legumes, and nuts, as well as cereals (bread, pasta, rice, and whole grains). A moderate intake of dairy products, fish, poultry, and eggs as main protein sources, with small amounts of red and processed meat, is also typical. The use of olive oil as a main fat source and water as a beverage of choice are other common features. Infusions and optional moderate amounts of wine taken with meals, and a preference for seasonal, fresh, and locally low-processed products are also characteristic of the diet.
Key Components of the Mediterranean Diet:
- Abundant Plant Foods: Fruits, vegetables, whole grains, legumes, and nuts form the base of the diet. Aim for 2 to 3 servings of fruit and four or more servings of vegetables daily.
- Healthy Fats: Olive oil is the primary source of fat, providing monounsaturated fatty acids. Nuts and fatty fish also contribute beneficial unsaturated fats.
- Moderate Protein: Fish, poultry, and beans are preferred over red meat, which should be limited.
- Dairy in Moderation: Choose low-fat options like skim or 1% milk, low-fat cottage cheese, and low-fat Greek or plain yogurt.
- Limited Processed Foods: Focus on fresh, seasonal, and locally sourced ingredients.
Red Wine and Cardiovascular Health: Exploring the Connection
The potential benefits of red wine in the Mediterranean diet have been attributed to its polyphenol content, particularly resveratrol. Polyphenols are plant compounds with antioxidant properties. They are found in abundance in the Mediterranean diet. Red wine contains relevant amounts of polyphenols, for which evidence of their biological activity and positive health effects are abundant. These compounds have been credited with various health benefits, including reducing the risk of heart disease, dementia, depression, and insulin resistance.
The Role of Polyphenols:
Polyphenols are widespread in the diet and are considered at least partly responsible for the health-protective effects of fruit and vegetable-rich diets. The dietary intake of polyphenols varies largely among individuals. It is estimated to range from a few hundred mg/day to more than 1800 mg/day depending on the region and target population, as well as the methodology used for the assessment. Hydroxycinnamic acid esters, namely caffeoylquinic acids and flavan-3-ols oligo/polymers (i.e., proanthocyanidins), are usually reported as the most important groups of consumed polyphenols, followed by anthocyanins and flavonols. In general, the contribution of phenolic acid derivatives and flavonoids tends to be equilibrated, although there are differences across countries and population groups as a function of their dietary habits. For example, there are higher proportions of flavonoids in Mediterranean regions, while phenolic acids would predominate in non-Mediterranean countries. The main food sources for individual polyphenols tend to be similar among individuals, with coffee, tea, and fruits as major items, and vegetables and red wine in a second range. Moderate red wine drinkers consume polyphenols at levels well above the population average.
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Despite the fact that the antioxidant capacity of polyphenols is well-substantiated in vitro and has been recurrently associated in the literature to their health effects, the little bioavailability and large biotransformation of most polyphenols in the organism raise doubts that this activity can have a primary role on their in vivo effects. Although this possibility might not be discarded for particular compounds or situations, nowadays, other alternatives are considered to contribute to the in vivo effects of polyphenols. For example, they could act as modulators of gene expression and intracellular signaling cascades involved in cell function and protection. There is also increasing evidence about the crucial role of the interactions between polyphenols and gut microbiota as a mainstay to explain the health benefits of their consumption. A vast majority of the consumed polyphenols reach the large intestine unaltered, where they can be catabolized by the colonic microflora to a variety of metabolites. Some of these metabolites can be biologically active, and be responsible for the activity associated with their parent polyphenols. Among others, this would be the case of tyrosols, produced from oleuropein and related phenolics from olive oil, with putative effects against some types of cancer; urolithins, involved in the lipid-lowering effects and improvement in the cardiovascular risk biomarkers of ellagitannins; or estrogenic S-equol, enterodiol, and enterolactone, derived from soy isoflavones and lignans, respectively. The role of other metabolites, such as phenolic acids and aldehydes resulting from the bacterial breakdown of flavonoids, is still uncertain, although they might be expected to contribute to a part of their effects, both at the local and systemic level.
Additionally, unabsorbed polyphenols and phenolic metabolites can also have an impact on the composition of the gut microbiota, acting as prebiotic-like compounds. For instance, they have been suggested to be able to decrease the Firmicutes/Bacteroidetes ratio, linked to obesity trends in humans, and increase the abundance of beneficial Bifidobacteria and Lactobacilli spp., while producing a reduction in the levels of Bacteroides, Streptococci, Enterobacteriacae, or Clostridia. In the end, several mechanisms might be involved in the biological effects of polyphenols and contribute to their health benefits. Most of the available information on the biological activity and effects of the phenolic compounds has been obtained from in vitro, ex vivo, and animal studies, whereas data directly obtained in humans are scarce, and restricted, in general, to short-term intervention trials on a reduced number of people. Some attempts have been made in Mediterranean cohorts, whose results support the role of polyphenol-rich foods to the health benefits of the Mediterranean diet. Nevertheless, assessing the precise contribution of dietary polyphenols to those benefits remains complex, owing to the fact that the same food sources are also rich in other bioactives, such as vitamins, minerals, dietary fiber, or other antioxidants, which should also contribute to the health effects.
However, it's crucial to acknowledge that alcohol, even at low levels of intake, may have severe consequences for health. Alcohol consumption is associated with increased risks of cancer, neurological harms, injuries, and other adverse outcomes. The IARC classifies alcohol as a Group 1 carcinogen, causally associated with the development of cancers of the upper digestive tract and liver, and, with sufficient evidence, can be positively associated with colorectum and female breast cancer. It is therefore tricky, if not irresponsible, to spread any message on the benefits of moderate wine drinking, about which no actual consensus exists. Other hallmarks of the Mediterranean diet are the richness in virgin olive oil, fruits, grains, and vegetables, which are also good sources of polyphenols and other phytochemicals, and lack the risks of wine.
Recent Research Findings:
A recent study published in the European Heart Journal found that light-to-moderate wine consumption (half to one glass per day) among individuals at high risk of cardiovascular disease who followed a Mediterranean diet was associated with a 50% reduction in the risk of cardiovascular events. Light drinking (between one glass per week and less than half a glass per day) reduced cardiovascular risk by 38%. However, the health benefits disappeared in people who drank more than one glass of wine per day.
This study used urinary tartaric acid, a biomarker of wine consumption, to provide a more accurate measurement of wine intake. This approach helps to address the limitations of previous studies that relied on self-reported alcohol consumption.
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Expert Perspectives:
While the study suggests a potential benefit, experts caution against drawing definitive conclusions. Cheng-Han Chen, MD, an interventional cardiologist, stated that "Throughout decades of research, we have not found a clear benefit of wine/alcohol intake to heart health. Conversely, we know a lot about the harms of drinking. Because of this, the World Health Organization states that no amount of alcohol use can be considered safe or beneficial."
Rigved Tadwalkar, MD, a consultative cardiologist, noted that the study "provides intriguing insights into the potential cardiovascular benefits of light-to-moderate wine consumption, particularly for individuals at high risk of cardiovascular disease who are adhering to a Mediterranean diet." However, he emphasized that the study demonstrates a correlation but does not establish causation.
Jayne Morgan, MD, a cardiologist, highlighted the conflicting evidence surrounding resveratrol, a compound found in red wine. She stated that "the risks of alcohol intake outweigh any potential benefits for most individuals. Resveratrol is not as protective as previously touted and not worth the intake of wine or alcohol in order to try to achieve the benefits."
The Importance of Moderation and Context
If occasional to moderate wine consumption with healthy meals is not a ritual that you are interested in abandoning, the Mediterranean diet presents an example of how to enjoy alcohol in moderation in a way that may support cardiometabolic health and help to foster positive social connections.
It's important to note that the definition of "moderate intake" differs depending on the population and even the country. Generally, thatâs like 12 ounces of a regular beer at 5% ABV and about 1.5 ounces of tequila, bourbon, or any sort of distilled spirit. In other countries, based on their population, sometimes itâs up to three drinks a day for women and four for men. In Mediterranean countries, it is similar to one to two drinks per day, but generally, it is even less. Some interesting drinking patterns involve having like two ounces at a time â in the morning, and then with lunch, and then with dinner and so on. So itâs almost like theyâre having a tipple all day long, but itâs never a huge amount.
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Potential Harms of Alcohol Consumption:
- Increased risk of heart disease, cancer, liver cirrhosis, and other chronic health conditions.
- Increased risk of high blood pressure.
- Potential for alcohol dependency.
- Adverse effects on mental well-being and cognitive function.
Lifestyle Factors: A Broader Perspective
Experts agree that lifestyle factors are the most important components of reducing cardiovascular disease risk.
Key Lifestyle Factors for Heart Health:
- Healthy Diet: Emphasize fruits, vegetables, whole grains, lean proteins, and healthy fats.
- Regular Exercise: Engage in physical activity regularly.
- Adequate Sleep: Prioritize sufficient sleep.
- Weight Management: Maintain a healthy weight.
- Cholesterol and Blood Pressure Management: Keep cholesterol and blood pressure levels within healthy ranges.
- Stress Reduction: Manage stress levels effectively.
- Tobacco Avoidance: Avoid tobacco use and secondhand smoke.
Olive Oil: A Cornerstone of the Mediterranean Diet
Olive oil, and especially virgin olive oil (VOO), is one of the products most usually associated with the health properties of the MedDiet. Its regular consumption has been claimed to provide benefits against a number of disease conditions, such as atherosclerosis, diabetes mellitus, obesity, cancer, or neurodegenerative diseases. It is well-known that olive oil is very rich in monounsaturated fatty acidsâmainly oleic acid, accounting for up to 80% of its total fatty acidsâwith acknowledged positive effects on the profiles of plasmatic lipoproteins, triglycerides, and platelet aggregation, which has been linked to protection against cardiovascular and neurodegenerative diseases.
VOO also contains a series of biologically active polyphenols, in a concentration that oscillates within a large range from 50 to 1000 mg/kg, depending on the olive cultivar and ripening stage, environmental factors (climate, altitude, agricultural practices), extraction techniques, storage conditions, and time. VOO possesses a unique phenolic composition mainly consisting of secoiridoid derivatives, the most abundant one being oleuropein, the glucosylated form of 3,4-dihydroxyphenylethanol-elenolic acid (3,4-DHPEA-EA). Oleuropein is considered the main compound contributing to the bitterness of olives. Other related secoiridoids are the ligstroside aglycone (p-HPEA-EA) and the dialdehydic form of elenolic acid linked to either hydroxytyrosol (3,4-DHPEA-EDA; oleacein) or tyrosol (p-HPEA-EDA; oleocanthal), both existing as aglycones and glucosyl derivatives. Besides, VOO also contains phenolic alcohols such as tyrosol (p-HPEA) and hydroxytyrosol (3,4-DHPEA), mostly derived from their se-coiridoid precursors.
Olive oil phenolics have been extensively studied for their potential to counteract the onset and progression of a variety of chronic and aging-related diseases, and is attributed to hypoglycemic, anti-obesity, cardioprotective, neuroprotective, antimicrobial, and anti-cancer properties. Several in vitro and in vivo studies have associated the health-promoting effects of olive oil phenolics to their antioxidant and anti-inflammatory potential as related to their ability to modulate a series of molecular pathways. Intervention studies have shown that VOO-rich Mediterranean diets are effective in reducing several inflammatory markers. A compound that demonstrated strong in vitro anti-inflammatory properties is oleocanthal, with a structure that resembles ibuprofen, which was shown to cause a dose-dependent inhibition of cyclooxygenase enzymes COX-1 and COX-2. The beneficial effects of phenolic compounds from olives and olive oil (i.e., hydroxytyrosol and oleuropein complex) were recognized by the European Food Safety Authority (EFSA), which authorized health claims in relation to polyphenols in olives and the protection of LDL particles from oxidative damage, the maintenance of normal blood HDL-cholesterol concentrations, the maintenance of normal blood pressure, and âanti-inflammatory propertiesâ.