Dangerous sulfur dioxide on human health?
In short, it is not 100% harmless.

Is it harmful wine with sulfur dioxide?
Significantly less harmful than a bag of dried fruit.

SO2 can cause adverse effects on asthmatics, even at such low doses as 1 mgL. For this reason, some doctors just in case recommend asthma renounce drinking wine.

For most people, sulfur dioxide is safe in the doses used in winemaking. Yes, those who drink wine regularly, and you can exceed the recommended medical norm. However, there is reason to believe that this rate is underestimated – the same “just in case”.

The content of sulphur dioxide in wine is governed by a number of bodies of different countries. In Russia it is set by GOST 32030-2013:

The mass concentration of total sulfur dioxide in the Russian dry table wines and dry table wine materials should be no more than 200 mg/dm3; in semi-dry, semi-sweet and sweet – no more than 300 mg/dm3.

In the European Union set maximum allowable concentrations of SO2 to wines of different types: from 160 mg / l for dry red to 300 mgl for sweet white and 400 mg / l for botrytised wines.
In Australia the law allows for 250 mg / l in dry wines, and 350 mg / l in wines with a residual sugar content higher than 35 g / L.

In the USA the maximum permitted level of SO2 is the same as in Australia. In this wine, which his more than 10 mg / l, must contain the words “contains sulphur dioxide”.

By the way: sulphur dioxide contained in any wine, even if it was not added during production. The fact that SO2 is a byproduct of fermentation. The yeast in the process, produce approximately 5-15 mg / l quite naturally. Therefore, wines with no SO2 did not happen at all.

In the European Union there are talks about whether to require wine producers to indicate on the label all potential allergens and their concentration, not just the notorious sulphur dioxide.

On the basis of experiments on animals, the world Health Organization has established the RDA (recommended daily allowance) of SO2 in the amount of 0.7 mg per kilogram of body weight.

Some simple calculations will give you the recommended limit in 49 mg of SO2 per day for a person weighing 70 kg.
Half a bottle of wine with a sulfur dioxide content of 150 mg / l 56 mg of SO2, which exceeds the who recommended maximum.

Many people who have bad consequences of drinking wine, such as headaches, redness – blame it on the sulfur dioxide. Partly because it seems the first candidate, as a chemical additive which for most is automatic evil.

However, the impact of wine on the body, including negative is a truly complex mechanism, the individual factors which is still not completely understood.

At the same time, many foods contain a higher level of SO2 than wine. In particular, in dried fruits it is about 10 times more.

Source: Jamie Goode “The science of wine”