What is Tartaric Acid?
Tartaric acid is a white, crystalline organic acid that occurs naturally in many plants, including grapes, tamarinds, and bananas. It is one of the primary acids found in wine and is a byproduct of the winemaking process. There are different forms, or isomers, of tartaric acid, but the L(+)-tartaric acid is the most common natural form and the one approved for use as a food additive.
Its properties as an antioxidant, acidity regulator, and flavor enhancer make it a valuable ingredient in both the food and cosmetic industries. In food, it is often added to candies, jams, jellies, and soft drinks to provide a distinct tart taste. As a salt, potassium bitartrate is more commonly known as cream of tartar, a substance used in baking and as a household cleaning agent.
Is Tartaric Acid Safe in Food?
For most people, consuming tartaric acid in the amounts typically found in processed foods and beverages is perfectly safe. Regulatory bodies worldwide, including the U.S. Food and Drug Administration (FDA), have evaluated its safety. The FDA classifies it as a "Generally Recognized as Safe" (GRAS) substance for its intended uses in food. The European Food Safety Authority (EFSA) also sets a high acceptable daily intake (ADI) for tartaric acid.
FDA and EFSA's Stance
The FDA has listed L(+)-tartaric acid as GRAS, allowing its use in food production under good manufacturing practices. The EFSA, following a re-evaluation, established a group ADI of 240 mg/kg of body weight per day for tartaric acid and its salts, a level that is unlikely to be exceeded through normal dietary exposure. In general, the amount of tartaric acid you would consume from a typical diet is well within the safe limits set by these organizations.
An important exception exists for young children. Tartaric acid is not permitted as an additive in food specifically for infants and toddlers due to potential developmental intolerance.
Potential Side Effects and Risks
While safe in food quantities, ingesting very large or concentrated amounts of tartaric acid can be harmful. The most significant risk comes from intentional misuse or accidental ingestion of concentrated forms, such as high doses of cream of tartar.
The Risk of Hyperkalemia
Cream of tartar (potassium bitartrate) is extremely high in potassium, with a single teaspoon containing a significant percentage of the daily recommended value. Consuming large amounts can lead to a dangerous condition called hyperkalemia, or excessive potassium levels in the blood. Symptoms of hyperkalemia include:
- Abdominal discomfort and pain
- Muscle weakness
- Abnormal heart rhythms
- Nausea and diarrhea
This risk is especially high for individuals with pre-existing kidney disease, as their kidneys may not be able to filter out the excess potassium efficiently.
Gastrointestinal and Kidney Issues
Overdosing on concentrated tartaric acid can also cause acute gastrointestinal irritation, leading to nausea, vomiting, and diarrhea. In severe cases, large doses have been linked to acute kidney injury and even death. This is not a risk associated with normal dietary intake but is a serious concern with misuse.
Uses of Tartaric Acid Beyond Food
Tartaric acid has diverse applications in other industries, including:
- Skincare and Cosmetics: As an alpha-hydroxy acid (AHA), it's used in exfoliating products and serums to improve skin texture and reduce signs of aging. High concentrations can cause skin irritation, redness, and increase sun sensitivity. Proper use involves patch testing, starting with low concentrations, and using sun protection.
- Pharmaceuticals: It is used as an excipient to improve the taste of oral medications and in the manufacture of effervescent salts.
- Industrial Applications: Historically, it has been used in metal polishing, dyeing, and photography.
Comparative Safety of Food vs. Concentrated Tartaric Acid
| Feature | Tartaric Acid in Food | Concentrated Tartaric Acid/Cream of Tartar |
|---|---|---|
| Usage Amount | Small, regulated quantities | Large, unregulated amounts |
| Regulatory Status | Generally Recognized as Safe (GRAS) | Not for unsupervised, large-quantity consumption |
| Safety for Humans | Very high safety profile for most individuals | High risk of toxicity and hyperkalemia |
| Key Component | L(+)-Tartaric acid | Potassium bitartrate (rich in potassium) |
| Common Effects | Provides a tart flavor; generally no side effects | Nausea, vomiting, abdominal pain, irregular heartbeat |
| Targeted Organs | None in normal use | Kidneys and cardiovascular system in overdose |
How Much is Too Much?
For the average person, consuming the estimated lethal dose (LD50) of tartaric acid would require ingesting more than 500 grams (over a pound) at once, an amount far beyond normal dietary intake. The primary danger lies not in food consumption, but in the intentional or accidental swallowing of large, concentrated amounts, often from sources like cream of tartar. In such cases, the high concentration of potassium is the main concern.
Conclusion
In conclusion, the answer to the question "Is tartaric acid safe for humans?" is a resounding yes, provided it is consumed in the normal quantities found in food and beverages. It is a safe and regulated food additive (E334) with a long history of use. The danger arises exclusively from the misuse of concentrated forms, such as high-dose ingestion of cream of tartar, which poses a serious risk due to its high potassium content. It is essential for consumers to understand the distinction between normal food use and concentrated, supplemental ingestion to avoid adverse health outcomes. An excellent resource on the FDA's position on Generally Recognized as Safe substances, including tartaric acid, can be found here: FDA Guidance.
