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rebaudioside A

Also known as: Reb A, steviol glycoside, stevia sweetener, Rebaudioside A

Overview

Rebaudioside A (Reb A) is a natural, non-nutritive sweetener extracted from the leaves of the Stevia rebaudiana Bertoni plant. It is a diterpene glycoside and one of the primary steviol glycosides responsible for the sweet taste of stevia. Reb A is widely used as a zero-calorie sugar substitute in foods and beverages, particularly for individuals aiming to reduce caloric intake or manage blood glucose levels. It possesses a high sweetness potency, being approximately 200-400 times sweeter than sucrose, and is known for its clean sweet taste with minimal bitterness compared to some other steviol glycosides. The research on Reb A is moderately mature, with several randomized controlled trials (RCTs) and systematic reviews conducted. While generally recognized as safe (GRAS) by regulatory agencies, the evidence regarding its direct therapeutic benefits on conditions like hypertension or diabetes, beyond its role as a non-caloric sweetener, remains limited and inconsistent.

Benefits

Rebaudioside A's primary benefit lies in its efficacy as a non-caloric sweetener, which aids in reducing caloric intake from sugars. This makes it a useful sugar substitute for individuals managing weight or blood glucose levels, such as those with diabetes or hypertension, as it does not raise blood glucose. However, high-quality clinical evidence does not strongly support direct therapeutic benefits on these conditions. Meta-analyses of randomized controlled trials indicate that Rebaudioside A does not significantly reduce systolic blood pressure (mean difference: approximately -0.36 mm Hg) or other cardiovascular risk factors. While some physiological functions, including antihypertensive and antidiabetic effects, have been suggested, clinical evidence for these beyond its sweetening property is limited and inconsistent. The overall effect sizes on blood pressure and glucose are small or non-significant, and clinical significance remains uncertain. The quality of evidence for these purported therapeutic benefits is mixed, with some RCTs having adequate methodology but often limited by small sample sizes and heterogeneity.

How it works

Rebaudioside A primarily functions as a sweetener by activating the sweet taste receptors (T1R2/T1R3) located on the tongue, providing a sweet sensation without contributing calories. Its metabolic impact on the body is minimal due to its poor absorption in the upper gastrointestinal tract. Once ingested, Rebaudioside A is largely metabolized in the colon by gut microbiota, which break it down into steviol. Steviol is then absorbed and subsequently excreted from the body. There are no established direct pharmacological targets related to cardiovascular or metabolic effects; its action is predominantly confined to taste perception and its subsequent role in reducing sugar intake. This unique metabolic pathway contributes to its zero-calorie status and makes it suitable for individuals monitoring their caloric and sugar intake.

Side effects

Rebaudioside A is generally recognized as safe (GRAS) by regulatory agencies, and no major safety concerns have been identified at typical consumption levels. The most commonly reported side effects, though mild and infrequent, include gastrointestinal symptoms such as abdominal fullness, epigastric pain, and dizziness. These symptoms are generally mild and occur in a small percentage of users. Rare allergic reactions are possible but not well-documented. Serious adverse events have not been reported in high-quality clinical trials. There are no significant documented drug interactions with Rebaudioside A, and no specific contraindications have been established. It is considered safe for use in special populations, including individuals with diabetes and hypertension, as it does not impact blood glucose levels or significantly affect blood pressure. Overall, its safety profile is robust, making it a well-tolerated sugar substitute.

Dosage

There is no established minimum effective dose for therapeutic effects of Rebaudioside A, as its primary use is as a sweetener. Typical sweetening doses in foods and beverages range from 100 to 400 mg per serving. Regulatory bodies have established an acceptable daily intake (ADI) for steviol glycosides, including Rebaudioside A, which is generally set at 4 mg/kg body weight/day, expressed as steviol equivalents. This ADI represents the maximum safe dose for daily, lifelong consumption. No specific timing considerations are required for its consumption. Rebaudioside A is typically used in purified powder or liquid forms in food products. Its low systemic absorption and metabolism by gut microbiota are key factors in its safety profile, as it does not accumulate in the body. No specific cofactors are required for its function or absorption.

FAQs

Is rebaudioside A safe for diabetics?

Yes, Rebaudioside A is a non-caloric sweetener that does not raise blood glucose levels, making it a safe sugar substitute for individuals with diabetes.

Does it lower blood pressure?

Current scientific evidence, including meta-analyses, does not support a significant blood pressure-lowering effect of Rebaudioside A alone.

Can it cause side effects?

Mild gastrointestinal discomfort, such as abdominal fullness or epigastric pain, is possible but uncommon. Serious side effects are rare.

How sweet is it compared to sugar?

Rebaudioside A is approximately 200-400 times sweeter than sucrose (table sugar), meaning only a small amount is needed for sweetening.

Is it natural or artificial?

Rebaudioside A is a natural compound extracted directly from the leaves of the Stevia rebaudiana plant.

Research Sources

https://pubmed.ncbi.nlm.nih.gov/25412840/ – This systematic review and meta-analysis of 9 RCTs (756 participants) investigated the effects of steviol glycosides, including Rebaudioside A. It found that while stevioside showed small reductions in diastolic blood pressure and fasting glucose, Rebaudioside A did not significantly affect blood pressure or cardiovascular risk factors. Mild gastrointestinal symptoms were reported as adverse events. The study noted limitations due to heterogeneity and small sample sizes, particularly in participants with high cardiovascular risk.
https://journals.sagepub.com/doi/10.1177/2047487314560663?int.sj-full-text.similar-articles.1 – This meta-analysis focused specifically on randomized controlled trials involving pure Rebaudioside A. It concluded that Rebaudioside A had a non-significant effect on systolic blood pressure, with a mean difference of –0.36 mm Hg. The authors acknowledged limitations due to the limited number of studies and small effect sizes, suggesting the need for further research.
https://pubmed.ncbi.nlm.nih.gov/36524621/ – This comprehensive review article discusses Rebaudioside A as a safe, zero-calorie sweetener with potential physiological benefits, including antihypertensive, antidiabetic, and anticaries effects. However, it highlights that clinical evidence for these benefits is limited, often relying on preclinical or observational data. The review emphasizes the need for more robust clinical trials to confirm these potential therapeutic effects, while affirming its safety and physicochemical properties as a sweetener.