Which Grapes Are High in Resveratrol? A Comprehensive Guide

Resveratrol is a natural phytoalexin produced by grapes, mainly in their skin, as a defense mechanism against fungal infections and environmental stress. Red grapes generally contain a higher concentration of this potent antioxidant than green varieties, but certain cultivars stand out for their exceptional levels.

Quick Summary

This guide examines the specific grape varieties, such as Muscadine and Pinot Noir, that contain the highest levels of the powerful antioxidant resveratrol. It also details the key factors influencing concentration, including grape skin thickness, climate, and winemaking techniques.

Key Points

• Red is Best: Dark red and purple grapes, especially their skins, contain significantly more resveratrol than green grapes.

• Muscadine Grapes are a Top Source: Native American muscadine grapes (Vitis rotundifolia) are known to have exceptionally high resveratrol levels.

• Pinot Noir Leads Wine Grapes: Among common wine grapes, Pinot Noir is often cited for its high resveratrol content, particularly from cooler climates.

• Thick Skins Matter: Grapes with thicker skins, like Malbec and Petite Sirah, tend to have higher concentrations of the antioxidant.

• Climate is a Key Factor: Environmental stress, such as that experienced in cooler climates, can cause grapes to produce more resveratrol.

• Winemaking Influences Extraction: For wine, longer maceration (skin contact) during fermentation increases the amount of extracted resveratrol.

• Whole Foods vs. Supplements: Resveratrol from natural sources like grapes and berries provides synergistic benefits with other compounds, potentially offering advantages over supplements with poor absorption.

Understanding Resveratrol in Grapes

Resveratrol is a polyphenolic compound that has gained significant attention for its antioxidant properties. It plays a crucial role in a grape's natural defense system, with concentrations often increasing in response to stressors like fungal attacks or UV light exposure. The compound is found almost exclusively in the skin of grapes, which is why red grapes and red wine typically have higher amounts than their green or white counterparts. The amount of resveratrol varies widely among different grape varieties, and is influenced by several factors beyond just color, including genetic background, climate, and viticultural practices.

The Highest Resveratrol Grape Varieties

Certain grape varieties are consistently cited for their superior resveratrol content, making them the best choice for maximizing your intake of this antioxidant through natural food sources.

Muscadine Grapes (Vitis rotundifolia)

Native to the southeastern United States, muscadine grapes are a standout in the world of resveratrol content. Studies consistently show that muscadines possess one of the highest levels of this compound, along with other polyphenols. A unique feature of muscadines is that their skins are particularly rich in antioxidants, though often discarded in waste. However, some analyses have shown that even muscadine wine can contain more resveratrol than wines from other grape varieties. The high polyphenol content and robust defense mechanisms of muscadines contribute to their high antioxidant profile.

Pinot Noir Grapes

Often highlighted in discussions about wine and health, Pinot Noir grapes are known for their high resveratrol levels. The concentration is particularly elevated in grapes grown in cooler, moister climates, where the vines experience more environmental stress. This stress encourages the grapes to produce more of the antifungal compound. While Pinot Noir grapes have thinner skins compared to some other red varieties, the specific growing conditions and winemaking processes often result in a significant extraction of resveratrol.

Malbec Grapes

Malbec grapes are distinguished by their thick skins, which contribute to a very high resveratrol content. As the compound is concentrated in the skin, a thicker-skinned grape naturally has a higher potential for containing more resveratrol. Wine made from Malbec grapes often undergoes a longer maceration process, which further extracts the compounds from the skins and boosts the final resveratrol concentration.

Petite Sirah and St. Laurent

These grape varieties are also frequently mentioned among those with the highest resveratrol content. Similar to Malbec, their robust characteristics and thick skins are key contributors to their high concentrations of this valuable compound.

Resveratrol Content: Red vs. Green Grapes

The most straightforward distinction in resveratrol content is between red (or black) and green (or white) grapes. This difference is primarily due to the concentration of the compound in the grape skins.

• Red and Black Grapes: These varieties, with their deep-colored skins, are rich in anthocyanins and other antioxidants like resveratrol. The longer skin-contact period during red wine production also serves to maximize the extraction of these beneficial compounds.
• Green and White Grapes: While still containing some resveratrol and flavonoids, green grapes have a significantly lower concentration of resveratrol compared to their red counterparts. For instance, white wine is made without the grape skins, so it contains far less resveratrol than red wine.

Factors Influencing Resveratrol Levels

Beyond the grape variety itself, several other elements play a critical role in determining the final resveratrol concentration.

• Climate and Location: Grapes grown in cooler climates and at higher altitudes tend to have higher resveratrol levels. The vines produce more of the compound in response to environmental stresses.
• Winemaking Process: For wine, the amount of skin contact during fermentation is crucial. Longer maceration periods, where the grape skins and seeds remain in contact with the juice, lead to higher resveratrol extraction.
• Fungal Infection: In some cases, exposure to certain fungi can naturally elicit a stronger defense response from the plant, increasing resveratrol production.
• Organic vs. Conventional: While not a definitive rule, some suggest that organic wines may contain higher resveratrol levels due to more natural growing practices and potential higher exposure to environmental stressors.

Comparison of Resveratrol in Grape Varieties

Grape Type	Resveratrol Content Level	Key Factors Influencing Content	Comments
Muscadine	Very High	Thick skin, genetic background, natural resilience	Native American species, consistently high in polyphenols.
Pinot Noir	High (Varies)	Climate (cooler), winemaking process, thin skins	Thinner-skinned grape, but specific conditions can yield high levels.
Malbec	High	Thick skin, winemaking process (maceration)	Thicker skin contributes to higher concentration.
Merlot	Moderate	Genetic background, processing	Generally contains less than Pinot Noir but more than green grapes.
Cabernet Sauvignon	Moderate	Thick skin, winemaking process	Moderate levels compared to the highest varieties.
Green Grapes	Low	Color (lack of dark pigment), processing	Contains some flavonoids but significantly less resveratrol.

Conclusion

If you are looking to maximize your resveratrol intake directly from grapes, focusing on specific red and purple varieties is the most effective strategy. Muscadine grapes, along with wine varieties like Malbec, Petite Sirah, St. Laurent, and Pinot Noir, are among the top contenders for their high resveratrol concentration. Remember that the amount can fluctuate based on environmental conditions and processing methods, especially for wine. While supplements are available, the bioavailability of resveratrol from whole foods is an important consideration. Including a variety of these grapes in your diet provides not only resveratrol but also a host of other beneficial nutrients. For more information on the health benefits of this compound, a good resource is the National Institutes of Health.

List of Other Resveratrol Sources

• Peanuts
• Peanut Butter
• Blueberries
• Cranberries
• Mulberries

Frequently Asked Questions

Do green grapes have any resveratrol?

Yes, green grapes do contain some resveratrol, but in significantly lower concentrations than red or purple grapes. The compound is predominantly found in the skin, which has less pigment in green varieties.

Which type of red wine has the most resveratrol?

Wines made from grapes with naturally high resveratrol content, such as Pinot Noir, Malbec, Petite Sirah, and St. Laurent, generally contain the most. Pinot Noir is frequently cited as a leader due to environmental factors in its typical growing regions.

Does red grape juice contain resveratrol?

Yes, red grape juice does contain resveratrol, as it is made from the skins of red grapes. The concentration can vary but provides a notable source of the antioxidant.

Are resveratrol supplements more effective than getting it from grapes?

Not necessarily. Studies indicate that resveratrol from supplements can be poorly absorbed and rapidly metabolized by the body. Consuming it from whole food sources like grapes provides the compound along with other beneficial nutrients and fiber.

How do winemaking techniques affect resveratrol levels?

Winemaking techniques, especially maceration, heavily influence the amount of resveratrol in the final product. A longer maceration process, where the grape skins are in contact with the juice, allows for greater extraction of the compound.

Does the growing region affect resveratrol levels in grapes?

Yes, climate and region are important. Grapes grown in cooler climates and at higher altitudes often develop thicker skins and produce more resveratrol as a defense mechanism against environmental stresses.

Do all grapes have the same amount of resveratrol?

No, the resveratrol content varies significantly based on the grape's genetic background, skin thickness, growing conditions, and exposure to environmental stressors. Red and purple grapes generally have more than green varieties.