Soda water and its effects on your health
Prof. Dr. habil. Dinya Zoltán, DSC
„You should drink for your health realizing how important it is”
Soda water or carbonated water, soda water, club soda, sparkling water, seltzer, seltzer water or fizzy water as it is called in English is part of our everyday life as a clean drink or a flavoured drink or a drink added other substances or alcohol (such as wine or gin etc.).
Soda water is made by adding carbon-dioxide (CO2) to water under pressure. Carbon dioxide mixed with water produces carbonic acid (H2CO3) and the pH of this solution is between 3 and 4 and the solution is bubbly and fizzy due to free carbon dioxide. Club soda is popular in the USA and Britain that is soda water, still, it contains, depending on various manufacturers, common salt, sodium citrate, sodium hydrogen carbonate sodium sulfate or disodium hydrogen phosphate to reduce acidity ( In Britain, soda water actually always contains sodium hydrogen carbonate (its popular name is soda bicarbonate)) .
Brief history of soda water
Water with natural carbon dioxide content (soda water) had been bottled in the town of Selters, Germany since the 18th century for trade purposes. The name “Seltzer water” comes from this German town name . In 1767 Joseph Priestley brewer from Leeds, England noticed that the air released when beer was fermenting produced a delicious soft drink if it is led into water. History of soda water continued. Later, in 1772 he developed carbon dioxide from chalk and sulfuric acid and led into water [2-3]. Another Englishman called John Mervin Nooth improved Priestley’s equipment and later his device was used in pharmacies. Independently from him a Swedish chemistry professor called Torbern Bergman produced water containing carbonic acid in a similar way. The famous Swedish chemist Jöns Jacob Belzelius was the first person at the end of the 18th century to add spices or fruit juice to soda water so he was the first producer of flavoured soda water.
At the end of the 18th century J.J. Schweppe watchmaker from Switzerland and of German origin developed a method based on Joseph Priestley’s invention for soda water production then in 1783 he established his company called Schweppes Company in Geneva, then in 1792 it was transferred to London. This company has been working since then and has become a world famous corporation.
Ányos Jedlik Hungarian natural scientist (1800-1895) also had an important part in spreading and popularizing soda water all over the world .
„ Artificial mineral waters benefit from adding free carbonic acid into water in a greater quantity than ever or the content of natural waters and this fact is honour for inventors. ” – this concept starts the study written by Ányos Jedlik in Latin that is a brief summary of the original procedure made by Jedlik and the title is: “way of making of soda water, water with sodium and magnesium, Eger, Selters, Püllna water víz”.
In 1828-29, as a teacher of the Benedictine secondary grammar school in Győr he started to study and discover the way of making soda water and artificial acid-water to be also used for the industry in Hungary. He had read about this issue in chapter 12 of Gilbert’s work called “ „Annalen der Physik” which said that in Geneva Paul and Goffe both physicists started to make acid-water in 1798 but they kept the way of preparing in secret. Jedlik did not need any external help as he had successful experiment with good results soon and the soda water prepared by him was made.
He wrote: „… a device is needed for the process which is fit for filling water with carbonic acid by developing carbonic acid gas by this particular device…”. He described the way of preparing as follows: „ A certain quantity of sulfuric acids diluted by three or four parts of water is poured in the first vessel for developing carbonic acid gas. Afterwards chalk ground to powder, ground marble or screened wood ash that is even better are mixed with water to make liquid pulp and it is pushed into the same vessel by a piston. As the major part of the air has been driven by the generated gas through a free gap the vessel is closed hermetically. The ash is added several times so the carbonic acid gas is passed from the first vessel into the second one through a tube that reaches to the bottom of the second vessel.
This second vessel contains the solution of soda or ash fat that cleans the gas from any sulfuric acid vapours delivered. The carbonic acid gas cleaned and thickened can be poured into a third cylinder vessel by opening a tap where the water to be saturated can be found. The water gas is replaced in the vessel to be moved by hand until the sulfuric acid becomes saturated by gas.”
The works performed&results achieved by Ányos Jedlik concerning soda water contributed greatly to the fact that the Hungarian drink “fröccs” (“wine spritzer”) made from wine and soda water became well-known and favourite in several countries in Europe.
Later, in the second half of the 20th century soda water started to capture the market all over the world first of all as flavoured hard drinks with alcohol or soft drinks without alcohol with carbonic acid. Soda water is the basic liquid of various alcohol drinks (e.g. whisky and soda) generally applied.
Soda water has become the part of our everyday life.
Soft drinks made from soda water
In the last decades various flavoured and artificially sweetened forms of soda water have been widespread  the so-called soft drinks or recently the so-called “energy drinks” with caffeine and L-carnitine ”. Soft drinks (in English: pop soda, coke, soda pap, fizzy drink or tonic etc.) can contain alcohol but their alcohol content is <0,5%. Soft drinks usually consist of soda water, sweeteners, flavourings and/or fruit juice. Sweeteners are usually sugar (saccharose, glucose, fructose or corn syrup with great fructose content (invert sugar) or as sweetener replacing sugar in its diet versions. Flavouring/aroma substances generally applied are cola, lemon, citrus extracts, grapes, vanilla, ginger etc.
Phosphate soda containing lemon and/or orange juice and phosphoric acid is very popular in the USA, which appeared at the end of the 1870s and was the most popular soft drink until the 1930s.
The broad list of modern soda water based soft drinks can be found on the internet . 
The effects of soda water and soft drinks with carbonic acid on the health
There have been several positive and negative assumed or real statements concerning health mainly in the media and on the internet or less in the scientific journals along with the spreading and drinking of soda water and soft drinks with carbonic acid all over the world. These statements and results are summarized and critically assessed as follows.
The effects of soda water on the health
There are only a few negative experience influencing health and scientifically supported on soda water.
- Consumption of soda water cannot cover the daily liquid need or intake depending on age. The effect of soda water depends on rations just like for other substances. The recommended daily consumption of soda water is appr. 1 liter at the maximum.
- No energy (calories) is taken by drinking soda water.
- Basically, the value of soda water is determined the quality, mineral composition and carbonic acid/carbon dioxide content of the “basic water”. pH of healthy soda water is to be between 3-4 (3,4-3,6 is the optimal value).
- Based on the recent data one of the most supported objection or negative fact against soda water or soft drinks with carbonic acid content is connected with the metal cans of aluminum content in which they are filled and distributed. There is an assumption but no proved facts about aluminum in other words it may contribute to the development of Alzheimer disease a neurodegenerative disease resulting in mental degradation. To avoid this risk factor that has not been proved definitely it is recommended to drink soda water or soft drinks with carbonic acid content in bottles of plastic bottles (smaller bottles are more recommended).
- One of the most frequent counter-arguments or negative comment against soda water is erosion of dental enamel („acid erosion or caries), discoloration of teeth or decayed teeth in other words deterioration of teeth. These negative statements however have not been proved and they are not right but unfortunately they are probably true for soft drinks with carbonic acid and high level of sugar content and/or with phosphoric acid content [7-9]. The findings of scientific tests have proved that teeth deteriorate much quicker if soft drinks with sugar and/or phosphoric acid content are drunk permanently compared to drinking clean soda water. (If teeth are cleaned after drinking these negative effects can be reduced considerably!). When carbon dioxide dissolved in water a smaller quantity of carbonic acid is generated that acidifies water to a slight extent (pH 3-4). If a “healthy” tooth is put into soda water or flavoured soda water without any sugar and it stays for a longer time no changes can be experienced. (Unfortunately, that is different for drinks with higher acid and sugar content.) This statement is especially true if soda water is made from basic water of good quality as the effects of carbonic acid is balanced by the calcium and mineral content of small quantity protecting dental enamel. Permanent use of soda water can cause an enhanced damage of still weak dental enamel for young children (4-7 years) . It is not recommended for elderly people (>50) to drink soda water due to the condition of teeth according to their age. Soda water destroys the bacteria of the oral cavity and it protects our teeth . Phosphoric acid reduce calcium content of bones including teeth (see cola) considerably as phosphoric acid inhibits bone growth and enhance bone metabolism (it strongly enhances osteoporosis). The probability of fractures or decayed teeth also enhances . The scientific data received so far [13-14] prove that drinking simple soda water or flavoured (sugar free) soda water is considered as a negligible factor concerning damage of dental enamel or deterioration of teeth and soda water use does not enhance the probability of fractures.
- Another general counter-argument or negative misconception related to soda water is that drinking soda water causes throat and stomach injuries or digestion system problems or enhances the development of reflux disease and oesophagus cancer.
- Soda water has effect of bacteria killing. It enhances mouth hygiene [15-16], reduces “mouth smell” caused by bacteria and it is especially recommended for people travelling in foreign (tropical) countries. Soda water inhibits virus flu symptoms or development of herpes.
- The scientific results achieved so far [17-21] do not support the above mentioned negative statements, however, in experiments conducted in vitro chicken embryo tissues  histological (morphological) data were found related to the unbalanced extracellular calcium.
- The counter-argument saying soda water changes stomach acid pH is not true. It does not change it permanently to such an extent that it inhibits digestion. What is more, according to the experience made so far soda water promotes digestion and it reduces the feeling “fullness” after substantial meals. Soda water does not dilute stomach acid so that is also a misconception. It reduces nausea or sickness (e.g. a frequent side effect for patients under chemotherapy). Soda water promotes discharge of excrement so it reduces symptoms of constipation. It is not recommended for patients suffering from inflammatory intestinal diseases (IBD) or Chron diseases to drink soda water permanently.
- There are communications in literature (summary l. 1 literature 21) that make reference to the fact that soda water enhances so called reflux diseases (GERD disease) and there are other studies describing opposite conclusions. Johnson &Co.  believe this negative effect is not considerable for soda water but it is significant for strongly acidic soft drinks with pH 3 or under (e.g. pH of some well-known drinks RC Cola:2.4, Coca Cola:2.5, Pepsi Cola:2.5, Diet Pepsi:3, Seven Up:3.2, Diet Coke: 3.3, Sprite: 3.3). The present results do not prove a close connection between drinking soda water and reflux diseases [18-21], in other words they do not influence the physiological condition of the upper digestion tract.
- Drinking soda water has benefits for sportsmen and people performing heavy manual work. Drinking soda water reduces muscle pains, enhances muscle functioning, reduces feeling of tiredness and promotes digestion. it is especially beneficial if after any competition or race sportsmen soak legs or arms in soda water or they are washed/flushed with soda water (it has essential disinfection effect!).
- When you drink soda water/soft drinks with high sodium content you have to consider that enhanced level of sodium intake can lead to high blood pressure in other words it can increase the risk of diseases due to high blood pressure (e.g. apoplexy, infarct, kidney diseases etc.).
- Soda water enhances kidney pressure or urination, and speed of alcohol absorption in blood stream .
- It is supported by several scientific surveys that soda water rich in calorie-free minerals reduces the whole or LDL cholesterol level by appr. 7,8 % or by appr. 10-12% and glucose level of blood serum [24-26]. Overweight people think simple water is not “delicious” enough for them but soda water is more accepted. Soda water can be considered as a natural “weight regulator” as drinking soda water contributes to the regulation of the energy household of the body needed for the prevention of metabolic syndromes such as diabetes II type. This statement is also true for children . From this aspect sugar-free soda waters with caffeine content are especially beneficial (for children or young people ≤15 years). Moderate drinking is to be considered (optimal quantity is 3-4dl every day). 
Soft drinks with carbonic acid content
Sugar-free flavoured soft drinks with pH value between 3 and 4 can be/are recommended, especially if they are based on healthy water with well-balances minerals and natural (plant) flavouring/additives have functional heath protecting effects in conformity with/based on the current scientific results.
The supported negative statements/facts that do not recommend or restrict soft drinks with carbonic acid can be connected with the following three facts: strongly acidic nature/ phosphoric acid content, sugar and/or artificial sweetener or high sodium content.
- High acid content
It has been discussed above. The data found in the literature mainly confirms or prove the common negative effect of phosphoric acid and sugar content. Bacteria in the mouth ferment acids from carbon hydrates enhancing high acid level. These facts can enhance the deterioration of teeth  or removing calcium from bones /osteoporosis, especially for women in a critical age .
- High sodium content
There are data concerning the fact [5,30] that drinking cola drinks in great quantities can cause low potassium level /hypokalemia/. Based on the studies in the reviews American J.Medicine or J. Nutrition healthy drinking waters/drinks with carbonic acid should have lower sodium content than 200mg/l .
(Remark: the negative effect of the higher content of drinks with carbonic acid can be reduced by bicarbonate concentration.)
- Carbon hydrate/sugar content
The negative effects of this fact are the most proved/supported that are mainly obesity, diabetes II type or enhanced deterioration of teeth both for children and adults [32-41]. Unfortunately artificial sweeteners (aspartame, saccharine etc.) have also negative effects e.g. they can enhance feeling of thirst (do drink more and more!) or sodium level and these can raise body weight [42-46].
Diabetic patients can drink sugar-free drinks with carbonic acid. Products with sodium benzoate content have not only the effect of raising sodium level but it causes hyperactivity for children or young people, which is a problem. Another more serious problem is the effect of damaging DNA due to benzene generated therefrom.
The quantity of benzene in the soft drinks tested is 4 or 5 times higher than in tap water .
The current scientific results do not confirm or in many cases do not contravene the negative views or believes related to soda water. Soda water made from proper water has several proved positive effects protecting or influencing health. It is recommended for health-conscious people. Drinking soda water free from sugar and/or sweeteners flavoured with plant substances in a proper quantity is beneficial.
Strongly acidic soft drinks with carbonic acid have or may have negative effects influencing or damaging health if they are drunk permanently.
Organic water confirmation: