Allulose, the sugar that works miracles?

Carlos Sánchez 22 July, 2020 Carbohydrates Leave a comment

If there is one issue that is of the most importance in the food industry, and for consumers themselves, it is finding a sugar substitute that is actually healthy

Index

1. Sugar is Sugar
2. Alternatives to Sugar
3. What is Allulose?
4. Where is it found?
5. What effects does Allulose have on your health?
6. Is allulose safe?
7. Allulose and Energy Metabolism
8. Conclusions
9. Sources
10. Related Articles

Sugar is Sugar

I don’t think it is necessary to explain at this point why added sugar consumption is not recommended, in other words, that which is intentionally added when making a product or preparing a meal, whether it’s at an industrial or daily level.

This is important, because many people think that homemade pastries are much better than ultra-processed ones produced by the industry, but the reality is different: sugar is sugar whether it is in one’s house or in factory “X”.

I am only referring to sugar because this is the subject that we are covering, but this reasoning extends to refined flours or to low quality margarines and fats, for example

Let’s just say that, to this day, the search for the «Holy Grail» of food has not been entirely fruitful…

Alternatives to Sugar

There are some products on the market that are often perceived as the healthy alternative to table sugar, but are actually practically the «same dog with different collar».

We are referring to brown sugar, honey, syrup (agave or maple) or fructose itself, which was considered the healthy alternative to sucrose (common sugar)

Polyalcohols

We also find polyalcohols as widely used substitutes in industrial practices.

They are used as low-calorie sweeteners that appear naturally in foods such as fruits

Some examples are xylitol, sorbitol and erythritol

Although they are beneficial in preventing the occurrence of cavities, they can have laxative effects, which becomes their main disadvantage. In addition, there are people who are intolerant to this type of product

Sweeteners

On the other hand, there are acaloric sweeteners such as saccharin, aspartame, acesulfame-K or the well-known stevia.

From my point of view, these are the best option for quick sweetening, although it is true that it’s always better to try to get used to the real taste of food.

I would also like to clarify that according to the current evidence they are safe, but still do not escape from controversies and discussions about their safety and health effects

The search continues, and in recent years a new name has appeared on the scene: D-allulose or D-psicose

What is Allulose?

It is a natural sugar, low in calories, which possesses 70% of the sweetening power of sucrose.

Its appearance is that of white powder easily soluble in water

Most of the allulose is almost completely absorbed into the small intestine and excreted through the urine practically entirely, which makes little impact on energy metabolism. The unabsorbed fraction passes into the large intestine, where it is fermented

Molecular Structure

Structurally it is an epimer of fructose, which means that they have the same composition but have a variation in the location of one of the OH groups present in their structure.

It is seen more clearly in the following image:

Comparison of Fructose VS Allulose

This simple structural change makes it behave completely differently than fructose once it is absorbed, despite being almost identical molecules as we’ve already seen

Where is it found?

It is only present in products of plant origin such as the Itea plant or in some mixtures of glucose-fructose, steamed coffee, sugar cane processing or beet molasses and even in heat-treated fruit juices.

Because it is a rare sugar, it is found in very small amounts in very specific sources

In any case, the concentration is quite low in these products…

For this reason, methods were developed to achieve chemical synthesis, but due to the formation of waste products and the difficult subsequent processing to isolate it, alternatives have been sought to produce it biologically, through enzymes

Allulose in Commercial Products

Generally, Allulose in crystalline form has a purity of more than 98%, whereas in the form of syrups it can be found at 50 – 90% in combination with variable rates of fructose and glucose.

Depending on the type of commercial product in which it is found, the purity will be higher or lower

What effects does Allulose have on your health?

Allulose competes with glucose and fructose for intestinal transporters (GLUT5 and GLUT2), which means that it blocks the absorption of these two sugars, which has been linked to:

better insulin function,
reduced fat build up and
potential anti-diabetic effects.

Various studies suggest that it could have a anti-obesogenic effect

Allulose competes with fructose at the GLUT5 transporter level, which is responsible for introducing them from the intestine into the cellular interior, and with glucose and fructose at the GLUT2 level to pass from the enterocyte (intestinal cell) to the bloodstream.

Image taken from Hossain et al., 2015

This translates into potential protective effects against large increases in blood glucose levels:

Image taken from Hossain et al., 2015

Some clinical essays have shown that the administration of allulose together with maltodextrin at a ratio of 1:15 (one part of allulose per 15 of maltodextrin) was effective in reducing the elevation of blood glucose levels.

When 5 g of allulose were provided in isolation it did not affect blood or glucose or insulin levels, meaning that it does not induce hypoglycemia. In addition to all of the above it has been observed that it possesses anti-inflammatory and neuroprotective potential

Is allulose safe?

The FDA (U.S. Food & Drug Administration), the American Food and Drug Safety Agency, considers it a safe ingredient.

However, a clinical study showed maximum tolerable levels of:

0.5 g/kg weight/day in men
0.6 g/kg weight/day in women

In any case, the only attributable adverse effects are some transient gastrointestinal discomfort when ingested in high amounts. This is not considered toxicologically relevant

Allulose and Energy Metabolism

As we explained at the beginning, the absorbed allulose is not used as fuel, but that does not mean that it does not influence energy metabolism.

Study

A study was published last year (Kimura et al., 2017) in which the effects of allulose on postprandial energy metabolism in healthy individuals were evaluated. For this purpose, 5g of allulose (99% purity) was administered against 10 mg of aspartame (control) diluted in 150 ml of water, obtaining solutions of similar sweetness.

The design of this study was crossed, i.e. the subjects who consumed the allulose on the first occasion, took aspartame on the next intake that was made a week later, and vice versa.

This is important, as it eliminates a lot of confusing factors when dealing with results. In addition, the dinner that subjects had to eat was standardised the night before

The research protocol consisted of taking the allulose or aspartame 30 minutes before eating a breakfast consisting of 200g cooked rice and a 166g burger together with 150ml of water. Energy metabolism was measured after breakfast through exhaled air and blood analysis

Results of the study

Although baseline energy expenditure (REE in graphs) was no different between groups, the intake of allulose significantly increased the use of fat (FEE in graphs) at 90 minutes, the use of carbohydrates (EEC in graphs) and the respiratory ratio (RQ in graphs) being lower in this group.

For those unfamiliar with the terms, a high respiratory ratio (close to 1) indicates that carbohydrates are mostly being used as fuel, while a respiratory ratio close to 0.7 indicates greater energy dependence on fats.

In addition, the blood test showed a decrease in glucose levels at 90 minutes in the allulose group, as well as the presence of higher concentrations of fatty acids at 180 – 240 minutes

The authors highlighted the ability of allulose to increase fatty acid oxidation in the postprandial period, linking this finding to the anti-obesogenic properties attributed to allulose.

They also associate the lower use of carbohydrates with the blocking of glucose absorption and the action of the alpha-glucosidase enzyme, which is responsible for breaking down starches into simple molecules that can be absorbed

Conclusions

Allulose or psicose is a rare sugar present in certain products of plant origin. Despite presenting the same composition as fructose, a small change in its structure means it is not used as fuel or metabolized.
It has 70% of the sweetening power of sucrose and does not provide energy.
Although it is absorbed almost entirely, it is excreted by the urinary tract and has no adverse effects consumed in reasonable doses.
Its greater function appears to be its competition for absorption with fructose and glucose at the intestinal level, which is why it is attributed antidiabetic and anti-obesogenic properties, as well as other properties such as anti-inflammatory and neuroprotective ones.
It could stimulate the use of fats as fuel and improve insulin resistance, according to several studies..

On the other hand, its main cons are its high price (about 200g of crystalline allulose cost around 11€) and the lack of studies with large samples carried out in humans with various pathological states and over longer periods of time