D-Tagatose is a low-calorie sugar substitute that you may be hearing much about in the future. Various clinical studies have hinted that tagatose appears to be a healthier alternative to non-nutritive sweeteners like sucralose and aspartame, which are ubiquitous in processed foods. This naturally occurring simple sugar, which was discovered in 1897, looks like fructose but behaves differently in the body. Its potential benefits for blood sugar control, satiety, and weight loss have even sparked interest among researchers as a possible next-generation nutraceutical. To help you make sense of all of those, here's a summary of the results of the human research on D-tagatose, along with possible side effects.
What Is D-Tagatose?
D-tagatose is an odorless, naturally occurring, low-glycemic simple sugar that is consumed as a low-calorie alternative sweetener. First discovered in 1897 and later developed as a low-calorie sweetener in 1988, tagatose is 92% as sweet as table sugar (sucrose) but has fewer calories (1-2 cal/gram vs. 4 cal/gram).
Commercially, it is produced from lactose (milk sugar), which is broken down to form a sugar called galactose. Galactose, in turn, yields tagatose.
While it is derived from galactose, structurally, tagatose looks like another sugar called fructose. For the curious, the D in the name refers to dextro or dextrorotatory, which is Latin for “right.” In chemistry terms, the D means the molecule is right-handed.
What Foods Contain Tagatose?
Commercially produced foodstuffs contain far more than natural foods, where they exist in only trace amounts. For example, 3.5 oz of low-calorie ice cream may contain 5-10 grams; the same amount of sugar-free chocolate may have 3-8 grams.
For comparison, here are approximate amounts found in 3.5 oz (100g) of natural foods:
- Cows milk: 0.02 to 0.04 grams
- Yogurt: 0.01 to 0.03 grams
- Apples: 0.001 to 0.005 grams
- Onions: 0.0005 to 0.002 grams
- Garlic: 0.0003 to 0.001 grams
- Carrots: 0.0001 to 0.0005 grams
Unprocessed, natural foods contain so little of this molecule, which is why tagatose is classified as a “rare sugar.”
Tagatose is Safe
The FDA in the US, European Union, Canada, Australia, and New Zealand believe tagatose is safe for humans. The Food and Drug Administration granted GRAS status to tagatose in 2001. One reason a nutrient is accepted as Generally Recognized as Safe (GRAS) is that it has been consumed by people in foods without issue since 1958. Additionally, only 20% of oral tagatose is metabolized, meaning 80% is not used by humans.
It Is a Prebiotic
About 20% of orally consumed tagatose is absorbed by humans. The rest travels to the large intestine, where it is broken down by lactobacillus and streptococcus bacteria to produce short-chain fatty acids (SCFA).
Microbiome-produced SCFAs play roles in many physiologic processes, ranging from vitamin K synthesis and insulin sensitivity to immune system function and cancer protection.
One important short-chain fatty acid produced from tagatose is called butyrate. Various studies have suggested butyrate plays a role in:
- supporting the health of intestinal cells that line the gut wall
- colon cancer prevention
- insulin sensitivity
- brain function
- reducing inflammation
When healthy people were given 30 grams of tagatose daily, their SCFA production quadrupled after just two weeks. As such, don't be surprised if you one day see tagatose on the Supplement Facts labels of probiotics and other nutraceuticals.
D-Tagatose May Lower Blood Sugar
Tagatose appears to disrupt the absorption of carbohydrates, leading to a reduction in blood sugar. This has sparked interest in the possibility that it may be useful to people with diabetes. See below for more on this.
It May Be Better Than Stevia
C-peptide is a marker of how much insulin you are making. The more C-peptide produced, the more insulin you make. When researchers gave women with insulin resistance 2 oz (60 ml) of water mixed with either 5000 mg of D-tagatose or 15.3 mg of stevia, there was a potential worsening of insulin resistance in stevia users as measured by an elevation in C-peptide, compared to when women consumed tagatose.
Additionally, while both sweeteners improved satiety, only stevia raised blood sugar 30 and 60 minutes later. Equally intriguing was that only those consuming stevia reported an increased desire to eat.
Tagotose May Help Weight Loss
When researchers gave this sugar to people with type II diabetes for one year, 7 out of the eight people (87.5%) lost weight. The average reduction in body weight was 8.8 pounds (4 kg).
This reduction in body mass did not appear to be due to appetite suppression. While others have reported that D-tagatose slows gastric emptying, it appears the simple answer is related to the fact that people consumed fewer calories.
It's Good For Teeth
Xylitol is well known for blocking the replication of cavity-causing bacteria. While tagatose has a different structure than xylitol, is it possible it may work, too? To find out, researchers recruited 19 healthy men and women between the ages of 21 and 61 and had them chew gum that
contained either xylitol, D-tagatose, or a combination of both for four weeks.
Tagatose gum resulted in significantly reduced growth of the cavity-causing Streptococcus mutans bacteria. The effect was similar to that seen with xylitol. It remains to be seen if gum containing both tagatose and xylitol synergistically works better together.
Does It Help Diabetes?
In the 12-month study involving 8 overweight people with type II diabetes, HbA1c declined 1% from 10.6% to 9.6%. The authors of that study stated this was “non-significant.” However, if proven true in future studies, tagatose would promote meaningful improvements in health.
Each 1% decline in HbA1c you achieve is associated with a 21% reduction in diabetes-related deaths. Additionally, reducing Ac1 by just 1% is also associated with a whopping 45% reduced risk of death from heart disease.
Tagatose Raises GLP-1
Given that this low-glycemic sugar slows gastric emptying and may benefit those with diabetes, it's logical to wonder if tagatose also augments glucagon-like peptide-1 (GLP-1). In one clinical trial, when healthy people consumed 40 grams of tagatose, plasma GLP-1 levels increased higher at 60 minutes and 120 minutes after treatment compared to sucralose and glucose.
However, the sugar did not increase plasma levels of the other incretin hormone, GIP. While this is an interesting result, larger clinical trials are required to verify this outcome.
It Appears OK for Those with Gout
Given that tagatose looks like fructose, it's worth considering whether it is safe for conditions like gout, where uric acid is elevated. In one study, 8 healthy people were given 75 grams of tagatose for eight weeks. No rise in basal uric acid was observed, although there was a transient rise seen at the start of the trial.
A lower dose (45 grams/day) did not raise uric acid in another study. This is encouraging, but to know for sure, tagatose needs to be tested in those formally diagnosed with gout.
Effects on Cholesterol are Mixed
Diabetes is associated with metabolic dysfunction that affects not only glucose levels but cholesterol, too. In one study involving overweight men and women with type II diabetes, 45 grams of tagatose consumed daily with food was shown to significantly raise HDL (good cholesterol) from 31 mg/dl to 40.5 mg/dl. However, it did not significantly impact total cholesterol, LDL, or triglycerides.
Here's what the before and after results looked like.
| Before (mg/dl) | After (mg/dl) | |
| Total Cholesterol | 225 | 224 |
| LDL | 154 | 155 |
| HDL | 31 | 40.5 |
| Triglycerides | 222 | 246 |
The rise in HDL was likely due to weight loss, which was also seen in this study. Those using D-tagatose lost about 8 pounds (4 kg) over the course of the study.
Effects on Fatty Liver Disease Need More Research
Fructose and high fructose corn syrup are associated with increased triglycerides, which in turn raise the risk of non-alcoholic fatty liver disease, now called metabolic dysfunction-associated steatotic liver disease (MASLD). This is a precursor to the even more serious condition called cirrhosis of the liver.
Studies in healthy individuals have not reported elevations in liver enzymes or triglycerides in humans who consume D-tagatose.
Another clinical trial showed no increase in liver weight or liver glycogen storage when healthy men consumed 45 grams a day for a month. However, caution is warranted until researchers test this sugar in men and women who have fatty liver disease.
Tagatose Side Effects & Adverse Reactions
When consumed in amounts found in natural foods, tagatose is unlikely to provoke adverse side effects in most healthy people. However, in human studies involving higher doses, gastrointestinal problems have been reported when doses exceed 30 grams per serving. These symptoms include flatulence, bloating, and diarrhea. Some of this is likely due to gut bacteria breaking down sugar. A dry cough is a rare side effect reported in a minority of people who were evaluated.
In the longest clinical trial, which lasted 1 year, people taking 45 grams of tagatose experienced no harm to their liver or kidneys.
The Canadian version of the FDA – Health Canada – has stated that people with a rare genetic condition called Hereditary Fructose Intolerance (HFI) may want to avoid tagatose because both sugars share similar metabolic pathways. When people with HFI consume fructose, table sugar, or sorbitol, they may develop low blood sugar as well as damage to the kidneys and liver.
My Thoughts
The research on D-tagatose is intriguing, but one thing I noticed was that most of the human clinical trials were conducted over 20 years ago. Given the interest by the food and supplement industries, you would think there would be more recent investigations. Also, some study results need to be replicated in other clinical trials. If you are experimenting with tagatose to improve your health, consuming amounts less than those used in the studies outlined above should reduce the side effects you might experience.
What Do You Think?
References
- https://pubmed.ncbi.nlm.nih.gov/23760573/
- https://pubmed.ncbi.nlm.nih.gov/11029974/
- https://pubmed.ncbi.nlm.nih.gov/22158727/
- https://pubmed.ncbi.nlm.nih.gov/11350207/
- https://pubmed.ncbi.nlm.nih.gov/21147362/
- https://pubmed.ncbi.nlm.nih.gov/30334250/
- https://pubmed.ncbi.nlm.nih.gov/10647340/
- https://pubmed.ncbi.nlm.nih.gov/32843762/
- https://pubmed.ncbi.nlm.nih.gov/10341162/