Research Roundup: January 2020

This month, we have been debunking common detoxing myths and talking all things New Year’s Resolutions. Here at Nuzest HQ, we are committed to educating consumers through current research and providing resources and inspiration to help them be the happiest and healthiest versions of themselves. As part of this commitment, we thought that it would

This month, we have been debunking common detoxing myths and talking all things New Year’s Resolutions. Here at Nuzest HQ, we are committed to educating consumers through current research and providing resources and inspiration to help them be the happiest and healthiest versions of themselves.

As part of this commitment, we thought that it would be fun to share a ’roundup’ of the research that catches our eye every month and break it down into easy-to-digest summaries for you.

This month, we look at whether cleansing diets improve cravings, energy and sleep quality; we debunk the age-old myth that it takes 21- days to form a habit; and explore what happens to the blood glucose response when sugar is swapped for stevia!

Woman in sports clothes sitting on her bed and surfing the internet for research

‘Cleansing’ diets significantly improve self-reported health markers relating to cravings, energy levels and sleep quality

A small exploratory study in a community of Appalachia, US, has discovered that ‘detox’ diets purported to eliminate toxins from the body significantly improve certain self-reported health measures.

Volunteers for the study participated in a pre-defined ‘clean’ diet for three weeks and completed three anonymous surveys to track their progress: one pretest before beginning the program (PRE), one roughly one week after completion (1wPOST) and one follow-up eight weeks after the end of the diet period (8wPOST).

Thirty-four individuals completed the PRE surveys, 15 individuals completed the 1wPOST surveys and eight individuals completed the 8wPOST surveys. Results comparing the PRE, 1wPOST and 8wPOST surveys found significant overall differences seen in the health characteristics of craving sweet/salty foods, “giving in” to cravings, energy levels and sleep quality.

Due to the small sample size of this study and the fact that no clinical outcomes were measured, further research is needed to determine whether cleanses actually improve cravings, energy levels and sleep quality. However, the results of this exploratory study do provide interesting insight into the potential benefits that cleanses may have on mindset and the positive impact this may have on overall health.

Davisson L, Sofka S. “Cleanse” detoxification diet program in Appalachia: Participant characteristics and perceived health effects. J Complement Integr Med 2019;pii: /j/jcim.ahead-of-print/jcim-2018-0174/jcim-2018-0174.xml.

Read our article Detox Diets Part 1: Do Detox Diets Really Work? to see what the research says on this popular topic!

two happy women in sports clothes running and giving each other a hi-five

How the fallacy of the 21-day new healthy habit began with plastic surgery

With new year’s resolutions well underway, many people might still be thinking that it only takes 21 days to form a new habit. Truth be told though; this is simply not correct. In fact, it’s more likely to take you around three times as long.

According to an article in the British Journal of General Practice, forming a new habit within 21 days is unrealistic, and instead, it is more likely to take you 66 days for automaticity to plateau (meaning, it takes about 66 days for you to adopt a behaviour into your normal, everyday, autopilot routine).

It appears though that this myth originated from anecdotal evidence around patients who had received plastic surgery treatment and took approximately 21 days to psychologically adjust to their new appearance. Unfortunately for the rest of us however, this adjustment period somehow made its way into guidance around health habit formation.

Thankfully though, the article explores how psychological theory and evidence around simple and sustainable habit-formation suggests that working effortfully on a new habit for two to three months is the best way to make a new habit second nature! So simply starting on your resolution and working at it till the end of March should see you well on your way to making a healthy habit for life.

Gardner B, Lally P, Wardle J. Making health habitual: the psychology of ‘habit-formation’ and general practice. Br J Gen Pract 2012;62(605):664-666.

Have you seen our 5 Exercise and Lifestyle Tips to Create a Happier and Healthier You this New Year? If not, click here to read.

chocolate block cacao

How combining stevia and cocoa when baking muffins may help reduce glycaemic response

Muffins are delicious. There’s no doubt about it. But generally, they contain high amounts of sugar that when over-consumed, isn’t always so good for your health. As a team of nutrition-conscious foodies (hence why we love adding Nuzest Clean Lean Protein to our baking) we are always looking for ways to make the foods we love better for us and our tastebuds. Thankfully, a group of scientists from China and New Zealand heard our baking prayers and decided to test ways in which to make muffins healthier, while still remaining scrumptious. The results were published in Foods journal.

The aim of the study was to evaluate the effect of replacing sugar in muffins with either 50% or 100% stevia alongside adding natural flavour enhancers (cocoa and vanilla) for their effect on the physical properties of muffins and postprandial (after-meal) glycaemic response in comparison to a control muffin formulation with no stevia, cocoa or vanilla.

The results of the study? Nutritious and delicious.

The team discovered that replacing the sugar with stevia significantly improved in vitro (test tube) glycaemic response during digestion and helped to reduce the blood glucose response that is so commonly experienced following the consumption of high sugary foods. This is due to the fact that stevia lacks the calories and carbohydrates of sucrose, meaning there are no sugars released during digestion.

The study concludes that the full or partial replacement of sugar with stevia in muffins produces a treat with quality characteristics close to that of a full-sucrose muffin sample, however with greater associated health benefits thanks to a reduction in postprandial blood sugar levels. The results of this study provide an interesting avenue for future clinical (human) research.

Gao J, Guo X, Brennan MA, et al. The potential of modulating the reducing sugar released (and the potential glycemic response) of muffins using a combination of a stevia sweetener and cocoa powder. Foods 2019;8(10):pii:E644.

We had Clinical Nutritionist and Researcher Cliff Harvey investigate whether Stevia is safe to consume. See what he found in this article Stevia: Good or Bad? Everything you need to know.

Stevia: Good or Bad? Everything you need to know.

What is Stevia? Stevia originates from the plant Stevia rebaudiana, a perennial shrub originally native to Paraguay and Brazil in South America. The plant has been used traditionally for more than 1,500 years by the Guaraní peoples of South America who called it ka’a he’ê (“sweet herb”), and more widely for the last several hundred

What is Stevia?

Stevia originates from the plant Stevia rebaudiana, a perennial shrub originally native to Paraguay and Brazil in South America. The plant has been used traditionally for more than 1,500 years by the Guaraní peoples of South America who called it ka’a he’ê (“sweet herb”), and more widely for the last several hundred years in both Brazil and Paraguay.

The leaves of Stevia rebaudiana have been used to sweeten local teas, foods, and medicines, and have also been consumed as a sweet treat and medicine on their own. The herb was first described for botanical and medicinal purposes in the 19th century by the Swiss botanist Moisés Santiago Bertoni, and in the 20th century, the sweet-tasting glycosides that give stevia its sweet taste were isolated for other uses.

Nutrition Information

The active compounds in stevia are steviol glycosides; mostly stevioside and rebaudioside A. Stevia also contains more than 30 additional steviol glycosides, along with non-glycoside diterpenes, flavonoids, chlorogenic acids, and vitamins, many of which have antioxidant properties1. These steviol glycosides are approximately 30 to 300 times sweeter than sugar, depending on the particular glycoside2, and because the body does not metabolise these glycosides, stevia is also considered to be a zero-calorie sweetener.

Health Benefits

While stevia is most commonly known as a non-calorific sweetener, it is also a herb with a long history of use for medicinal purposes, particularly as an antihypertensive (reducing blood pressure) and anti-hyperglycaemic (reducing blood sugar) agent. Stevia is purported to also have a variety of other health effects, ranging from anti-microbial, anti-fungal, anti-viral, and anti-bacterial actions, to antioxidant actions3,4.

Stevia preparations have exhibited anti-inflammatory, oral health-promoting, antihypertensive, and cancer-protective effects and they might help to regulate blood glucose through some combination of improved glucose uptake, and possibly by improving insulin sensitivity7.

doctor writing at a desk

The Evidence for Stevia

A thorough review by The Natural Standard Research Collaboration ranked the scientific evidence as ‘good’ (‘B’) for the use of stevia for hypertension (high blood pressure) and ‘Unclear’ (‘C’) for hyperglycaemia (high blood sugar)8.

Other reviews of clinical trials have yielded additional benefits including:

  • Anti-inflammatory effects9 (reduced TNF-α, interleukin 6, interleukin 1β, and interleukin 10)
  • Improved blood glucose control9 (improved post-meal glucose levels when the meal contained stevia)
  • Improved satiety9 (patients do not compensate with more calories, versus when fed with sugar)
  • Significant improvements in systolic blood pressure10
  • Significant improvements in diastolic blood pressure11

Stevia and Diabetes

Research indicates that stevia may be a safe and effective way to help manage blood glucose levels in people with type 2 diabetes. Some clinical trial have reported significant reductions in blood glucose where type 2 diabetic patients were fed meals supplemented with stevia9. These findings indicate that stevia may help to maintain normal blood glucose levels if you have diabetes.

Stevia and Oral Health

As stevia is anti-bacterial it may have implications for oral health. Despite being sweeter than sugar, it offers a non-calorie sweetening option free-from sugar and other carbohydrates that can feed pathogenic bacteria. In vitro research has shown that stevia extracts have antibacterial activity against Streptococcus mutans and Streptococcus sobrinus, which are associated with tooth decay. Stevia may also help to reduce plaque formation by helping to inhibit bacterial biofilm formation12, thus it’s considered to be a non-cariogenic sweetener13 (i.e. does not increase dental decay).

two women happy at desk with laptop and paper working

Is Stevia Safe?

Perhaps the most interesting observation to have been reported is that there have been no adverse effects recorded over the many hundreds of years of use by Paraguayans14. On a biochemical level, the various steviol glycosides (i.e. stevioside, rebaudioside A and rebaudioside C) are metabolised and essentially leave the body without accumulation. Studies have shown that steviol glycosides found in stevia are not teratogenic (ie. they don’t cause physical or functional abnormality following fetal exposure during pregnancy), mutagenic or carcinogenic and cause no acute and subacute toxicity2,15,16.

Some earlier in vitro research had suggested that there might be some genotoxic (DNA damage) effects from stevia. However, the vast majority of scientific findings show no evidence of genotoxic activity and stevioside has not been shown to react directly with DNA or demonstrate genotoxic damage relevant to human risk17. The mutagenic activity of steviol and some of its derivatives, that had been demonstrated in a particular strain of bacteria (Salmonella typhimurium TM677)18, was not reproduced in the same bacteria having normal DNA repair processes. The only positive in vivo study showing DNA damage in Wistar rat tissue by stevioside was not confirmed in subsequent experiments and appears to be a result of differing measurements rather than actual damage to DNA17.

In any event, steviol and steviosides do not produce chromosomal damage or effects even at extremely high dose levels. In vivo reviews of the potential genotoxicity of stevia have concluded that it does not pose a risk of genetic damage following human consumption17.

Scientific analyses have also shown that daily oral intakes of 5mg/kg of body weight are safe, non-toxic and neither carcinogenic (cancer-causing) nor mutagenic14. A safety assessment in a review by The Natural Standard Research Collaboration suggested that 750-1500mg per day were likely to be safe in healthy and hypertensive adults. In the same review, caution was suggested for those with kidney disease, hypotension (low blood pressure), hypocalcaemia (low blood calcium levels), and hypoglycaemia (low blood glucose levels) due to insufficient evidence. Evidence for any harm resulting from stevia use for these conditions is equally lacking8.

Stevia is also stable at temperatures up to 200°C4.

Side-effects: allergy risk

Because stevia arises from the Asteracae/Compositae (daisy) family, those with known allergies to daisies and related plants should exercise caution with its use8. Reviews indicate that there have been no reports of allergy from stevioside use15.


Stevia has a very long history of use both as a sweetener and as a medicine, with no adverse effects having been reported over thousands of years of use, and no toxicity demonstrated in modern, scientific trials.

Stevia is non-cariogenic and non-calorific and so, offers benefits when compared to other sweeteners for oral health. While further research is needed to provide conclusive evidence for the medicinal use of stevia in weight management, diabetes and other health issues, it appears likely that there are (albeit small) benefits to blood pressure.

Overall, based on the available evidence, stevia is a safe and effective non-calorie sweetener that may also offer other health benefits.