Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Allulose is a kind of low-calorie sugar naturally existing in very small quantities, but now industrially produced as a commercial sweetener, said to have advantages that make it comparable to erythritol as a sugar substitute. It’s said to have anti-diabetic effects, but this was in obese mice. Allulose decreases LDL cholesterol levels in high-fat-fed hamsters, and is said to have a substantial impact on obesity in lard-munching mice, but what about men and women?
In a petri dish, allulose inhibits fat cell precursors from maturing into fat cells and reduced the amount of fat accumulation within fat cells. Here’s a before and after picture with the fat staining red, of swapping in some allulose for regular sugar. Therefore, the researchers conclude, allulose may be a promising sugar substitute for an anti-obesity diet. But you don’t know, until you put it to the test.
They gave people about a teaspoon of allulose a half hour before eating a meal, and compared to the no-sugar control group, the allulose group started burning more fat. The researchers concluded that allulose enhances after-a-meal fat burning, indicating that it could be a novel sweetener to control and maintain healthy body weight through enhanced energy metabolism. Okay, but first of all, it was only 15 calories of fat burned over that 4-hour period. And they didn’t burn more calories overall. They just switched from burning carb calories to fat calories, and so may have switched back later on and made up for it later in the day.
You can’t just look at one meal. You need to track people’s actual weight over time, and, here we go. A weight reducing effect of a syrup that included about 5 percent allulose, compared to high fructose corn syrup. The results showed significant decreases in body weight, body fat, and waist circumference, but it was some proprietary syrup mixture, and look, anything would look good against high fructose corn syrup.
This, is the study I’ve been looking for. Evaluating the effect of allulose for fat mass reduction in humans. Over a hundred individuals randomized to a placebo control, sucralose, or a teaspoon of allulose twice a day, or one-and-three-quarter teaspoons twice a day, and despite no change of physical activity or calorie consumption between the two groups, body fat was significantly decreased following allulose supplementation. They even took CT scans, so they could tell where the fat was disappearing from.
Now, the drop in body fat was only about 2 pounds over 12 weeks, and the drop in abdominal fat in the higher dose group was almost totally a drop in subcutaneous fat, the flabby superficial fat––not the dangerous visceral fat deeper down that really matters for health. But still, body fat loss despite no change in calorie intake similar to what was seen in the mice, but the hamster effect did not materialize. No significant change in LDL cholesterol in either of the allulose groups. What about the purported anti-diabetes effects?
If you have people chug a beverage with up to about two teaspoons of allulose alone, previously known as psicose, or with a big load of rapidly-digesting carbs, the allulose alone has predictably no influence on blood glucose or insulin concentration. Yet when you consume allulose along with the refined carbs, there was actually a suppression of the elevation of blood sugar and insulin, and by a significant amount: a 30 percent drop in blood sugar and insulin levels over a two-hour period.
We think it’s because the presence of allulose impairs the absorption of sugar through the intestinal lining, because they all might be competing for the same sugar transporter. Yeah, but who’s chugging maltodextrin? What about just like a regular meal?
And…here we go, and in borderline diabetics who could use some blood sugar spike suppression. A randomized double-blind placebo-controlled crossover experiment to see what drinking one and a quarter teaspoon of allulose in a cup of tea with a meal would do, and indeed a significant drop––though only about 15 percent. You can see how they tried to exaggerate the y-axis.
They also did a second experiment randomizing people to a little over a teaspoon of allulose three times a day with meals for 12 weeks. Nice to see there didn’t appear to be any adverse side effects, but they also didn’t find any weight loss effects in contrast with that other study. So, the body fat data are mixed, and so too are the sugar data. This study found no effects of allulose on blood sugars in healthy participants, though a similar study on diabetics did. A systematic review and meta-analysis of all such controlled feeding trials suggested that the acute benefit on blood sugars was of borderline significance, and it’s unclear whether or not this alone could translate into meaningful improvements in blood sugar control over time. So, maybe it’s not enough to just add allulose. You might actually have to also cut out the junk.
Although ability to suppress blood sugar responses is the most well studied aspect of allulose, I do just want to cover one last angle, the fact that allulose extends the lifespan of a tiny roundworm called C. elegans through a dietary restriction mechanism––even though they ate the same amount of food. Two months in, just a few percent of the control group were still alive, whereas twice as many in the low allulose group and about 25 percent still around in the higher allulose group. We think it worked by boosting the expression and activities of antioxidant enzymes in the body, extending lifespan by mopping up free radicals. But who cares about the survival curves of worms?
Well, C. elegans is a well-studied model of aging and longevity, but mostly just for convenience sake, but does share most of the longevity genes or pathways we’re interested in. It would be nice to see experiments on at least human cells, and here we go. The effect of allulose on free radicals and oxidative stress in human coronary artery endothelial cells––the cells that line the inside of our arteries. Add a bunch of sugar, and free radical levels shoot up, but add the same amount of sugar along with some allulose, and it’s as if you never even added the sugar, and this then translates to inhibiting the expression of an inflammatory marker that plays a role in the buildup of atherosclerotic plaque. However, it is still too early to draw conclusions about the clinical relevance of these data.
To conclude, are these rare sugars like allulose a healthy alternative for traditional sweeteners? Well, considering the variety of potentially beneficial effects of allulose without known disadvantages from metabolic and toxicological studies, allulose may currently be the most promising rare sugar. But how much is that saying? We just don’t have a lot of good human data. As a result of the absence of these studies, it may be too early to recommend rare sugars for human consumption.
Please consider volunteering to help out on the site.
