The factors influencing fluoride in wine
Several variables determine the fluoride content in a bottle of wine, making it difficult to generalize. Understanding these influences can help clarify why some wines may have higher levels than others.
- Natural Presence in Grapes and Soil: Grapes naturally absorb fluoride from the soil and water where they are grown. The concentration of fluoride in the soil itself, which can be linked to the region's geological and volcanic characteristics, is a primary driver of the mineral's presence in the fruit.
- Use of Pesticides (Cryolite): The use of fluoride-based pesticides, such as cryolite (also known as Kryocide), has historically been a major contributor to high fluoride levels in wine. This practice has seen greater use in certain regions, most notably California, to combat leaf-eating pests. European regulations on residual fluoride are much stricter, leading to lower levels in wines from those regions.
- Irrigation and Water Sources: The water used for irrigation and cleaning during the winemaking process can also impact the final fluoride concentration. In areas where the local water supply has naturally high or added fluoride, this can increase the overall mineral content in the wine.
- Winemaking Process: The specific production techniques can also affect the final mineral concentration. For instance, some studies have indicated that white wines tend to have higher fluoride levels than red wines, though other studies show no significant difference based on origin.
Is wine high in fluoride? A quantitative perspective
To put the amount of fluoride in wine into perspective, it helps to look at the numbers and compare them to recommended daily intakes and other sources.
- USDA Data: The USDA reports a glass of red wine contains approximately 154 micrograms of fluoride, while a glass of white wine contains 297 micrograms. Adult men are recommended to have 4 milligrams (4,000 micrograms) per day, and adult women need 3 milligrams (3,000 micrograms). Moderate wine consumption therefore contributes a fraction of the total daily intake.
- Parts Per Million (ppm): Studies have found wines made with grapes treated with cryolite can have fluoride levels ranging from 3 to 9 ppm. In contrast, those made without cryolite range from 0.1 to 1.6 ppm. To compare, the recommended level of fluoride in optimally fluoridated drinking water is 0.7 ppm. It's notable that a single glass of wine with 6 ppm fluoride can contain more fluoride than a liter of fluoridated water.
- Health Risk Assessment: Despite the varying levels, a 2016 study in the Biological Trace Element Research concluded that 'fluoride intake from wine poses no risk to the health of adults' when consumed in moderation. Regulatory bodies, such as the International Organisation of Vine and Wine, have set maximum fluoride limits (1 mg/L) that wines must meet for quality and safety.
How to choose lower-fluoride wine
For those seeking to limit their fluoride intake from wine, several strategies can be employed:
- Choose Organic Wines: Opting for certified organic wines is a reliable way to minimize exposure to cryolite pesticides, as organic farming practices generally prohibit their use.
- Select European Wines: Due to stricter regulations on fluoride residues, European wines are typically a safer bet for lower fluoride content than many American wines.
- Opt for Non-California American Wines: Since cryolite usage has been concentrated in California vineyards, choosing wines from other U.S. states like Oregon and Washington can help reduce fluoride intake.
- Consider Origin Information: Pay attention to the wine's origin. Volcanic soils, like those found in the Canary Islands, can naturally elevate fluoride levels in grapes grown there.
Comparison of fluoride sources and levels
| Source | Approximate Fluoride Concentration (varies by source/prep) | Reference(s) |
|---|---|---|
| Tap Water (Optimally Fluoridated) | ~0.7-1.0 ppm | |
| White Wine (avg, US) | ~0.3 mg/glass (~297 mcg) | |
| Red Wine (avg, US) | ~0.15 mg/glass (~154 mcg) | |
| Wine (cryolite-treated) | 3-9 ppm | |
| Raisins | ~2.34 ppm (per 1000g) | |
| Black Tea (brewed) | ~3.73 ppm (per 1000g) | |
| Seafood (e.g., shrimp, crab) | High concentrations |
Common dietary sources of fluoride
Beyond wine, many other foods and beverages are natural sources of fluoride, contributing to your overall dietary intake.
- Black Tea: The tea leaves themselves naturally contain high levels of fluoride, making brewed black tea a significant dietary source.
- Seafood: Crab legs, shrimp, and other seafood are known to be rich in natural fluoride.
- Grapes and Raisins: The grapes used to make wine are also a natural source of fluoride. Raisins, in their concentrated form, are particularly high in the mineral.
- Potatoes: Certain types, such as russet potatoes, contain a decent amount of fluoride, especially when baked.
- Other Fruits: A variety of fruits, including strawberries, bananas, and apples, also contribute to fluoride intake.
Conclusion
While grapes naturally contain fluoride and certain vineyard practices, like the use of cryolite, can increase its concentration, it is not accurate to label all wine as 'high in fluoride.' The levels vary greatly depending on factors like origin, soil, water source, and production methods. For most adults, moderate wine consumption contributes a safe, non-toxic amount to their daily intake, and regulatory limits exist to ensure product safety. For those concerned about intake, choosing organic or non-cryolite treated wines, such as many European varieties, is an effective strategy. It's important to remember that wine is just one of many dietary sources of this mineral.
For more information on recommended daily allowances and nutritional guidelines, you can visit the National Institutes of Health website.
