In the Low Carb Shrinks Your Brain? thread came this question:
What are your thoughts on Agave Nectar? The bottle says it has 16 grams of carbs per tablespoon and 60 calories, the same as honey. But it also says it has a low glycemic index. Is agave nectar easy on the blood sugar after all or not?
I'd appreciate your perspective. Thank you for all you do!
Ah, yes, agave nectar, the "healthy, natural" sweetener du jour. My nutrition-minded friends have, for the most part, accepted the idea that maybe carbs ain't all they're cracked up to be, whole grains aren't necessarily better than, say, wild-caught salmon or grass-fed beef. They've figured out fruit juice is a bad idea. Many even are hip to my use of unprocessed lard from pasture-raised pigs.
But just try telling them that your idea of a healthy diet includes artificial sweetener!
"But it's artificial," they cry. "How about honey?" they ask plaintively.
"Nope, honey is just sugar refined by bees."
"What about sucanat*?"
"More nutritious, but still a concentrated sugar, and still rough on blood sugar. Still gonna make me fat."
"Stevia! You can use stevia!"
"Well, for some things. It's fine in yogurt, but made a vile teriyaki sauce, and not even my dog would eat the stevia-sweetened cheesecake."
"AGAVE NECTAR! You can use agave nectar! It's NATURAL! And it has a really low glycemic index! That's it! You can use agave nectar!"
Sigh. One has to admire their tenacity. Sadly, like so many natural things, agave nectar is not health food.
Ironically, the heart of the agave plant, from which agave nectar is made, appears to be pretty healthy stuff. It's loaded with inulin, aka fructooligosaccharides, a carbohydrate which, while sweet, is classed with the soluble fibers rather than with the sugars. The stuff improves your absorption of calcium, and maybe magnesium, while nourishing the good bacteria in your gut. Inulin is one of the genuinely promising low carbohydrate sweeteners.
But is that good enough for the agave nectar folks? Nope. They use enzymes to break the inulin down into component sugars. In other words, they process it.. What results is a syrup of fructose and glucose, the same components as honey and table sugar. Except that, unlike honey and table sugar, both of which contain roughly equal quantities of fructose and sucrose, agave nectar is 92% fructose, 8% glucose.
This accounts for the claims of a low glycemic index. Unlike glucose, which can be metabolized by every cell in your body, fructose can only be metabolized in your liver. Apparently this slows absorption, leading to a seemingly low GI. Sounds good? Not so fast. According to Wikipedia:
There is a concern with Type 1 diabetes patients and the apparent low GI (glycemic index) of fructose. Fructose gives as high a blood sugar spike as that obtained with glucose. The basic GI measurement technique can be misleading. The blood sugar levels over time are graphed and the total area covered by this bell curve is used to calculate the GI number. This means that a slow release food can have the same GI rank as a food that raises the levels of sugar in blood, and lowers it again quickly.
In other words, fructose is still sugar, just a sugar subject to a metabolic bottleneck. As a result the blood sugar spike happens later -- a long enough time later that most glycemic index tests are over. But it gets worse.
Perhaps because of needing to be metabolized in the liver, fructose causes non-alcoholic fatty liver disease, making the livers even of teetotalers look and function like those of long-term alcoholics. Fructose is implicated in metabolic syndrome -- you know, carbohydrate intolerance, the thing we're all fighting. Repeated studies demonstrate that fructose raises triglycerides like nothing else. And there are some studies that indicate that the stuff is uniquely fattening.
(Completely speculative parenthetical note: It makes sense to me that fructose would be a trigger to store fat. Why? Because in a pre-agricultural world, fructose would only have been available in the form of wild fruit in season. A seasonal trigger to put on fat to get through the winter makes all kinds of evolutionary sense, especially when you keep in mind that that trigger would have coincided with the time of the year when the fattest game -- and therefore the greatest number of spare calories -- would have been available.)
All of this is why high fructose corn syrup is the current Nutritional Enemy Number One, and it couldn't happen to a more deserving substance. And I have to tell you, consuming lots of fructose in the form of "natural" agave nectar (no more natural that HFCS, which is also made by converting other carbohydrates into fructose using enzymes) is no better for you. Worse, actually, since the percentage of fructose in agave nectar is actually higher than that is HFCS.
In short, agave nectar is not your blissfully natural and healthful substitute for those evil artificial sweeteners. While I am not sure Splenda is 100% safe, I'm darned sure it's safer than nearly pure fructose.
If you are really afraid of Splenda, my best recommendation is one of the new erythritol/stevia blends on the market, or to simply stop eating sweet stuff. But agave nectar? Steer clear.
* Sucanat is unrefined sugar cane juice that is dried and ground into a coarse powder. It is, as I said, a concentrated sugar, but it does contain all the vitamins and minerals originally present in the sugar cane, which is a heckuva lot more than you can say for white sugar. It tastes much like brown sugar, though it doesn't have the sticky, packable texture.