23 March, 2008

Blowing the lid off Agave Nectar

Health foodies and diabetics beware! The short version: Agave Syrup/Nectar is NOT a health food item and is NOT good for people with impaired insulin & glucose metabolism.

Here's the longer version:
Agave syrup/nectar is 90% fructose and 10% glucose. (For some companies it's 97% fructose.) High fructose corn syrup contains anywhere from 55-90% fructose. Table sugar, or sucrose, is a dimeric molecule comprised of 1 glucose monomer plus 1 fructose monomer.

Fructose is the sugar molecule found mostly in fruit and a little in honey. When you eat fruit, you get vitamins and minerals, plus fiber which slows down the absorption of sugar. When you drink pasteurized fruit juice, you are drinking a pretty-colored fructose cocktail, perhaps with a few nutrients that survived the pasteurization process (Vitamin C is destroyed by heat). Sugars consumed without their associated minerals actually pull minerals from our bodily stores during their metabolism. Zoikes, scoob!

For thousands of years, human biochemistry evolved to process relatively low amounts of fructose. Fruit was consumed in season, when available, and as a whole food. Honey was a rare treat, not a pantry staple.

Onto the glycemic index. Agave syrup is often touted as healthy due to its coveted low-glycemic status. The glycemic index is a measurement of how a food affects blood glucose levels in comparison to glucose, as measured 2-3 hours after consumption. Glucose has a glycemic index measurement of 99 or 100, and is the sugar molecule our cells use most effectively as a direct energy source. Sucrose (table sugar) has a GI of 58-68. Fructose is anywhere from 11-25, and Agave Nectar about 10-11. So yes, Agave's fructose is considered low-glycemic when measured in this fashion. Because it cannot be processed by most of our body's cells, it doesn't immediately affect blood sugar metabolism.

Instead fructose must be catabolized by the liver, where it is turned into smaller molecules which bypass the body's glucose-regulating mechanisms. The fructose breakdown molecules readily enter the glycolysis (glucose metabolism) and lipogenesis (fat-producing) cycles. One result of this is an over-production of triglycerides (indeed this is the favored pathway--no other sugar converts to fat as readily as does fructose). Another result is the conversion of fructose into glucose. Interestingly, fructose also activates glucose uptake and metabolism.

Consuming regular, large amounts of isolated Fructose raises serum Triglycerides and Low Density Lipoproteins (and Very Low Density Lipoproteins). This also raises total cholesterol and adversely affects the HDL:LDL ratio. Not only does it alter blood lipids for the worse, fructose consumption also causes cells to be insulin-resistant, sending a message to the pancreas to pump out even more insulin! What happens as a result of insulin resistance and hyperinsulinemia? The body stores fat, primarily around the abdomen. And you crave more sweets--an addictive, vicious cycle. This condition is called the Metabolic Syndrome or Syndrome X, AKA Pre-Diabetes.

What other hidden effects does Fructose have?
-elevates uric acid. In one study, two servings of fruit juice per day increased a person's chances of developing Gout almost twofold over the placebo group. (Underwood BMJ 2008 336: 285-286) Elevated uric acid is also related to heart disease.
-especially contributes to insulin resistance in women who take oral contraceptives or HRT
-does not raise leptin levels comparatively to other sugars, so you don't feel satisfied after eating and may overeat.
-makes you lose minerals! Fructose consumption increases urinary output of calcium, magnesium, and phosphorous and intestinal (fecal) output of magnesium, iron, and zinc.
-may cause gastrointestinal upset and diarrhea
-raises levels of C-reactive protein, a marker for inflammation
-raises levels of homocysteine, an amino acid associated with cardiovascular disease
-contributes to atherosclerosis
-long-term use contributes to cirrhosis of the liver
-inhibits copper metabolism. copper is essential to connective tissue health, including collagen, elastin, bone, and arterial strength. it also plays a role in blood sugar metabolism. hmmm...
-between 1/10,000 and 1/50,000 people have hereditary fructose intolerance. Fructose jams up their glucose pathways and severe hypoglycemia results.
-Fructose may be especially problematic for people with high blood pressure, insulin resistance/metabolic syndrome, type 2 diabetes, bowel disorders, and postmenopausal women.

Now my brain is spinning from processing more biochemistry than I've read in 15 years! I think I need a shot of fermented Agave...


katie said...

wowsers-now to find an alternative. I'm always in awe of your brilliance, let's get together to play....the ever-so-insulin-resistant Katie ;)

Anna said...

So glad to see this. I've been concerned about the growing use of agave syrup for some time, but it's like being Chicken Little sometimes.

Takoda Rain said...

Wow, Im glad I read this. Thank you! Crap I put agave in everything!!

Papa said...

Good points, but let's not overreact.
1. Sugar is sugar... whether it's honey, agave, fruit, or refined table sugar. And agave is sugar.
2. Like honey & raw fruit, agave contains more nutrients than table sugar...
3. It has a higher fructose % than table sugar which means 2 things: it gets stored as fat easier BUT it has a lower affect on blood glucose... the glycemic index.

If the glycemic index is your concern... use agave or honey before table sugar...
If you want more vitamins/minerals... use agave or honey or raw fruits over table sugar...
If you're fat like me... and glycemic index is NOT your problem... use table sugar in your tea instead of honey/agave [or learn to drink it unsweetened, yuck!]

Just remember: Agave is NOT health food... it is sugar. But as a naturally occuring sugar, it's going to normally be a better choice than refined table sugar... even with its higher percentage of fructose. As always, the key is moderation.

Birthkeeper said...