Dr Justus Apffelstaedt: Wine and sulfur headaches – debunking the myth

On a recent international trip, I found myself seated next to a lady who insisted that white wine due to its sulfur content gives her severe headaches. I must admit, I’m highly skeptical of such claims in today’s post-factual world, where alternative ‘facts’ often rival, or even surpass, scientific ones.

In former times, sulfur got a bad rap due to its association with volcanoes, which often discharge foul-smelling sulfurous gasses and were believed to be direct entries to hell. The association with the smell of rotten eggs, caused by hydrogen sulfide (H₂S) gas and all manner of decay, did not help either.

In the food industry, sulfur – most commonly in the form of sulfur dioxide (SO₂, a sulfite rather than a sulfide) – is widely used as an antioxidant and preservative, effective against a broad range of spoilage bacteria and fungi. As an antioxidant, it prevents browning, for example in apples, and is generally recognized as safe. Sulfur dioxide enters the human body through food and is also inhaled in small amounts from the atmosphere.

Not only that, it is also generated in the human body as part of the metabolism of amino acids and serves as a messenger for physiological functions such as heart muscle recovery and anti-inflammatory effects. This already makes claims that it has negative health effects rather tenuous.

What SO₂ in wine really does – and doesn’t do

SO₂ is added to wine as a preservative and antioxidant at various stages of the winemaking process and in a well-run winery is measured at multiple points during the process. In the finished wine, South African law allows a maximum of between 150 mg/l in white and 300 mg/l in red wine of total SO₂ depending on the style of wine; the maximum for free SO₂ is 60 mg/l for all types of wine. These limits are considerably lower than the limits set by the International Organization of Vine and Wine (OIV). From my reading of multiple tech sheets, there is usually much less free SO₂ in South African wines.

What is the difference between free and total SO₂? Free SO₂ is available to do the job of preservation; in time it is used up by binding to other molecules and becoming “bound” SO₂. In an experiment in Bosnia-Herzegovina, experienced tasters could pick up SO₂ only in concentrations above 73 mg/l. This means that, in general, free SO₂ cannot be smelled or tasted in wine.

It is also the free SO₂ that is most likely to cause health trouble, but only when inhaled and not ingested. In the gut, there are potent mechanisms to take care of SO₂ and it is soon detoxified, entered into general metabolism, or excreted via the kidneys.

In the lungs, it may cause in sensitive individuals bronchospasm – meaning cramp-like contractions of airways leading to acute shortness of breath, wheezing, and chest tightness, especially in asthmatic individuals. This is a protective reaction of the lungs rather than an allergic reaction, as SO₂ is an irritant to the airways. Long-term exposure to high concentrations of SO₂ in inhaled air causes structural lung damage; the changes become irreversible and can lead to premature death.

Sensitivity to SO₂ is uncommon, occurring in less than 1% of the population and less than 10% of asthma sufferers. The most common source of SO₂ causing such symptoms is not wine, but rather smog from coal-burning power plants. It is for this reason that governments have limited the amounts of SO₂ that power plants are allowed to emit.

Case closed – with a glass in hand

Returning to the lady mentioned in the introduction: It is very rare that drinking wine leads to any sensitivity reaction due to its SO₂ content. This happens only in individuals extremely sensitive to it, and before any attributable headaches are caused, shortness of breath will long have been acute.

So I asked the lady whether she tolerates red wine, which she does. Generally, red wine contains roughly twice the amount of free SO₂ compared to white wine. Also, dried fruit – especially raisins – contains a lot of SO₂ (about 20 times the amount compared to red wine per kilogram of weight). When asked, she said she regularly puts raisins in her breakfast cereal.

For the rest of the journey, we had a stimulating conversation about a lot of other topics and enjoyed a couple of glasses – white wine for me and red wine for her.

With this, I rest my case: While Lucifer may make his presence known by the smell of sulfur hanging in the air, in wine it is not evil, but preserves our favourite drink. Cheers to that!

• Dr. Justus Apffelstaedt is a specialist in breast and thyroid health, leading Apffelstaedt & Associates in Cape Town and Windhoek. A surgeon with a specific interest in surgical oncology and researcher, he was Associate Professor of Surgery at Stellenbosch University (1994–2017) and Head of Surgical Oncology, managing 1,000-plus cancer cases annually. He has more than 50 publications, shaped South Africa’s breast cancer screening policy, and co-founded Breast Surgery International. A sought-after speaker, he has given over 100 international lectures. He also holds an MBA and a Diploma in Wine. Through Apffelstaedt & Associates, he continues to advance specialized, patient-centered care in Southern Africa.