I've Got a Headache...

By Leah Jorgensen

The French Paradox introduced the world to the concept that moderate wine consumption produced more health benefits than risks for the average person in good condition.

The most clearly established benefit of moderate alcoholic consumption, notably in red wine, relates to nearly 30 to 35 percent reduction in death rate due to cardiovascular disease. Further studies on the benefits of wine have shown that high doses of resveratrol, which is found in the grape skins, have been linked to longevity and cancer prevention.

A group of polyphenols, known as oligomeric procyanidins, which offer significant antioxidant protection, including the greatest degree of protection to human blood vessel cells, also reduce the absorption of malondialdehyde, which is implicated in arteriosclerosis, cancer, diabetes and other diseases. Other health benefits recorded from moderate wine consumption include: antimicrobial and, in some cases, antiviral effects; bone retention; reduced incidence of type 2 diabetes; and the reduction of kidney stones.

While there are lots of reasons for most adults to raise a glass for wine, there is a small percentage of wine consumers who complain about a host of symptoms and side effects stemming from wine. People with allergies and hypersensitivity may experience discomforts ranging from rhinitis, itching, allergic and allergic-like reactions, facial swelling, skin flush, headache, cough and asthma.  People are quick to assume the root cause for these reactions is from sulfur additions.

"Sulfur dioxide is blamed for a lot of reactions that are not actually SO2 related," explained John Zelko, physician and owner of Z'IVO Wines.

Free SO2 is bound to other compounds in wine, such as sugars, acetaldehyde and phenolic compounds, which come from grape skin and seeds. Since sulfites bind to these other chemical constituents, they are not as readily available as antigens, which are any molecule or molecular fragments that can be bound by a major histocompatibility complex (MHC) and presented to a T-cell receptor in the immune system.

There are typically more compounds in red wine for sulfur dioxide to bind with, and, thus, would produce less of an antigen response in the immune system than from white wine. Since most people who blame sulfites for headache and congestion responses are pointing at red wine as the major culprit, they are more likely experiencing a reaction from other compounds in wine - not from sulfites.

According to Zelko, the vast majority who experience typical allergy-like reactions, including headaches and sinus congestion, are more likely to have adverse reactions to histamines, organic nitrogen compounds involved in local immune responses, and tyramine, a naturally occurring compound derived from the amino acid tyrosine, which is produced by the decarboxylation of tyrosine during fermentation. In wine, these compounds are by-products of the fermentation process generally produced by the Pediococcus strain of bacteria.

"Typically, I tell people if they can eat at a salad bar, which uses anywhere from 200 to 300 ppm (parts per million) of sulfites, and not have a reaction, then it's highly unlikely that they are having reactions to the sulfur dioxide additions in wine," Zelko said.

To reduce the headache and congestion symptoms typical of histamine or tyramine reaction, Zelko suggests taking a Benadryl or other antihistamine ahead of time, and to drink plenty of water, which will help reduce the severity of headache.

For individuals who experience symptoms beyond a headache or congestion, such as a rash or difficulty in breathing, this might suggest sensitivity to sulfites. Occasionally, ethanol (alcohol) plays a role in these responses. However, the most common adverse reaction to sulfite compounds is asthma. A small proportion of wine sensitive asthmatics may experience bronchial constriction on exposure to sulfite. Adverse reactions to sulfite compounds in non-asthmatic and non-sensitive individuals are rare. Further, it has been clinically demonstrated that sulfur dioxide will generally precipitate an adverse reaction only in sulfite-sensitive asthmatics, which comprise approximately 1.7 percent of all asthmatics. Steroid-dependent asthmatics are most at risk of an adverse reaction.

Red wine tends to provoke more asthma problems than white, even though red wine typically has lower SO2 contents than white wine. Normally, sulfite is rapidly converted to sulfate by the enzyme sulfite oxidase in the blood. However, low levels of this enzyme could permit sulfite to persist provoking a heightened response in hypersensitive individuals. In these cases, a rare autosomal genetic disease caused by a deficiency in sulfite oxidase may be to blame.

Regulations have been set in place to limit the level of sulfur dioxide in wine, responding to the general health concerns to reduce the dietary intake of sulfur dioxide by optimizing the use of SO2 in winemaking. Data indicates the low concentration of sulfur dioxide observed in studies generally in wine was not problematic for a significant proportion of sensitive individuals. Further data implies the influence or role of sulfur dioxide and/or wine in triggering asthmatic adverse reactions may have been overestimated.

The legal maximum sulfite level for U.S. wines is 350 ppm, with most wines averaging about 125 ppm. Naturally occurring levels of sulfur dioxide in a wine, without chemical additives, would weigh in at around 10 to 20 ppm. Current FDA regulations in the U.S. require all wines, both domestic and imports, that contain 10-plus ppm of sulfur dioxide to state "Contains Sulfites" on the label. This label designation was intended to protect people who may be allergic to sulfites (an estimated 1 percent of the U.S. population).

There has been an industry-wide trend toward reducing sulfur dioxide use whenever possible. The reasons include health concerns, possible desire for a malolactic fermentation (that would otherwise be affected by the antimicrobial effects of SO2), and the enhanced suppleness of red wines that have had only limited sulfur dioxide additions.

So, why do many winemakers continue to use sulfites?

Sulfur dioxide is considered by many winemakers to be the most important additive used in winemaking, and is possibly the second most important winemaking practice, next to managing yeasts for alcoholic fermentation. It has been used for thousands of years as both an antioxidant and as an antimicrobial agent, and is quite effective at very low concentrations in the ppm range. Sulfur dioxide additions are key to preserving wine quality and freshness. Typically, it works best when enough is added at the proper time to accomplish the desired task without adding too much and adversely affecting wine quality. The amount and timing of additions depends on the style of wine and the composition of the wine to which it's being added.

"The approach is pretty scientific when using sulfur dioxide additions to ensure sound, clean wines," said Drew Voit, winemaker at Shea Vineyards, who uses minimal sulfur dioxide additions when the fruit comes in at harvest, during de-stemming, before his cold soaks, after malolactic fermentation, and during filtering and bottling.

"As with any wine technique, it's important to have knowledge of the science behind the skill," Voit added.

By understanding the chemistry of sulfur dioxide and what reactions occur when it's added to wine, the winemaker can make decisions that are based on goals for how the wine should ultimately taste like, allowing for it to work not only as a preservative but also as a tool to influence wine style. And, since this tool is used at regulated, minimal levels, its antimicrobial and antioxidant benefits far exceed the risks for adverse reactions affecting only 1 percent of the population.

For more information on the health risks of sulfites, visit www.pubmed.gov and search "sulfur dioxide." 

Leah Jorgensen is a freelance writer who has worked in the wine industry for over a decade. She consults for several wineries and is enrolled in the winemaking program at Chemeketa's Northwest Viticulture Center.