by Jeff Novick, MS, RD, LD/N
www.JeffNovick.com

Agave has become the sweetener of choice for many health enthusiasts. It is appearing on store shelves everywhere, in many new products and being promoted in magazines and cooking shows. One of the main benefits we hear is that it is lower in the glycemic index. Is agave really a health food and something you should be including in your diet?

No. To understand why, let us take a closer look at the issues surrounding agave.

To begin with, to understand agave, we have to understand some things about fructose which is the main form of sugar in agave and High Fructose Corn Syrup (HFCS). Fructose is metabolized differently than other sugars. Instead of going into the blood stream (where it could raise blood sugar), most of it goes directly to the liver. This is why fructose has a lower glycemic index (GI) as the GI is based on a food’s influence on blood sugar.

While many promote this as a positive, as the consumption of fructose tends not to raise blood sugar, fructose, or any concentrated caloric sweeteners high in fructose, can cause elevated levels of triglycerides and increase someone’s risk for heart disease. It may also somewhat increase the risk of metabolic syndrome/insulin resistance. And these effects are most likely in those who are insulin resistant, and/or overweight and/or obese. It also may not affect the satiety mechanism as well as pure sucrose. (1, 2)

For the record, these are all many of the reasons we are being told to avoid HFCS as it has a higher level of fructose than regular table sugar or regular corn syrup.

Here is the real irony in all of this.

Because of this concern about the elevated levels of fructose in HFCS, some health food stores will not carry any product that has HFCS in it. Yet on the other hand, they carry a full line of agave syrup products on their shelf and carry many products sweetened with agave syrup. But realize agave syrup has a fructose content of about 70-90% which is way higher (worse) than HFCS.

On the one hand, consumers, especially the health conscious, are avoiding HFCS like the plague because the level of fructose in it is higher (55%) than in regular table sugar/sucrose (50%). They consider the higher level of fructose a problem. The fact that is has a lower GI than table sugar is ignored.

On the other hand, agave syrup has become a popular sweetener because it is said to have a lower GI. They consider this to be a health benefit. The fact that it has the highest level of fructose than any other sweetener is ignored.

So, are higher levels of fructose in a concentrated caloric sweetener good or bad?

From my perspective, the glycemic index (and glycemic load) is a very poor indicator of how healthy a food is and I do not recommend choosing foods by it.

However, as agave is being promoted because of its low glycemic index, let’s look at the glycemic issue. Glycemic load (GL) amounts are also included; GL is the total amount of sugar released into the blood.

Sweetener	GI	GL	Notes
Fructose	13	2
Sucrose	65	7
Glucose	100	10
Honey	61	12	Depends on variety; range of 35-74 (GI) and 6-18 (GL)
Agave syrup	13	2	Depends on variety.

HFCS would be similar to a honey that has a similar fructose/glucose ratio because the composition and ratio would be the same. So, let’s say a GI of 45 (and a GL of 9) as a honey with the same ratio of fructose/glucose tested at 45 (and 9). HFCS has a lower GI (GL) than table sugar because of the higher level of fructose. The higher the percentage of fructose, the lower the GI is, with pure fructose being the lowest.

There are other concerns with HFCS and fructose and so potentially agave.

A recent study showed that when HFCS was exposed to warm temperatures, it forms hydroxymethylfurfural (HMF), a potentially dangerous toxic substance, and killed honeybees (3). Some researchers believe that this chemical, HMF, may be a factor in Colony Collapse Disorder, a mysterious disease that has killed at least one-third of the honeybee population in the United States.

In the study, the scientists measured levels of HMF in HFCS products from different manufacturers over a period of 35 days at different temperatures. As temperatures rose, levels of HMF increased steadily. Levels jumped dramatically at about 120 degrees Fahrenheit. They also mentioned other studies that have linked HMF to DNA damage in humans. In addition, HMF breaks down in the body to other substances potentially more harmful than HMF.

The researchers said, “Because HFCS is incorporated as a sweetener in many processed foods, the data from this study are important for human health as well.”

In this study, it was the effect of heat on fructose that formed the toxic chemical, so heating anything high in fructose corn syrup (HFCS) should be a concern.

However, remember, HFCS is about 55% fructose and agave syrup is about 70-90% fructose. Therefore, heating agave would potentially create more of this toxic chemical. Another strike against HFCS, but a bigger strike against agave.

There is more to the concern about heating fructose. It turns out that when fructose is heated it can also create Advanced Glycogen End Products (AGEs), which may be harmful as they may play a role in development of atherosclerosis, diabetes, aging and chronic renal failure.

One study compared the amount of AGE’s formed between a subject following a traditional omnivorous diet and one following a more traditional vegetarian diet (4). (NOTE: This was not the same type of vegetarian diet I would recommend!)

What the authors found was that the AGE’s levels were higher in the vegetarians. Upon closer examination, they discovered that it was higher levels of fructose in the vegetarian diet that was the main contributor to the increased level of AGEs and stated, “Comparison of nutrition and plasma AGEs in vegetarian and omnivorous groups shows that the higher intake of fructose in alternative nutrition of healthy subjects may cause an increase of AGE levels.”

In the above study, most of the AGEs were formed from the fructose which came from honey. As the authors stated, “Furthermore, the intake of honey is three times higher in vegetarians.”

Honey has one of the higher concentrations of fructose out of many of the typical sweeteners available and is around 55% fructose depending on the variety. Agave is 70-90% fructose. Therefore, substituting agave for any other sweetener would make the above results (of a potential increase in AGEs) more likely to occur. This is one more good reason to avoid agave.

Two last points:

A recent study in the journal Environmental Health (5), found mercury in nearly 50 percent of the tested samples of commercial high fructose corn syrup (HFCS). A separate study by the Institute for Agriculture and Trade Policy (IATP) detected mercury in nearly one-third of 55 popular, brand name food and beverage products where HFCS is the first or second highest labeled ingredient. The authors concluded, “With respect to total mercury exposure, it may be necessary to account for this source of mercury in the diet of children and sensitive populations.” This concern would only relate to HFCS, not agave.

A recent study (6) measured the antioxidant acuity level of several sweeteners and found that refined sugar, corn syrup, and agave nectar contained minimal antioxidant activity, raw cane sugar was slightly higher, and dark and blackstrap molasses had the highest antioxidant activity. Maple syrup, brown sugar, and honey showed intermediate antioxidant capacity.

Let’s put all of this in perspective…

Are higher levels of fructose in a concentrated caloric sweetener good or bad?

Well, if you think HFCS is bad because of the amount of fructose in it, then agave must be much worse than HFCS.

If you think agave syrup is good because it has a very low GI/GL, as a result of the fructose in it, than HFCS must not be that bad and at least better than table sugar because it has a higher level of fructose in it, and so would have a lower GI/GL than table sugar.

So again, are higher levels of fructose in a concentrated caloric sweetener good or bad?

We just can’t argue it both ways.

Now, as we see from these recent studies (1,2) , fructose, in excess, can create problems as it goes directly to the liver. However, these problems only existed when excess was consumed as there were no negative effects when less than 50 grams was consumed, even when it was pure fructose. So again, the real issue is quantity.

If it takes a minimum of 50 grams of fructose to see any negative effect and at least 100 grams of fructose to see a significant negative effect, let’s see how these numbers relate to potential intakes.

50 grams fructose would be the equivalent of consuming 100 grams of sucrose (sucrose is 50% glucose and 50% fructose) or consuming about 91 grams of HFCS (HFCS is typically 55% fructose and 45% glucose).

100 grams of fructose is the equivalent of 200 grams of sucrose or about 182 grams of HFCS.

100 grams of sucrose is 400 calories
91 grams of HFCS is 370 calories
200 grams of sucrose is 800 calories
182 grams of HFCS is 740 calories

On a 2000 calorie diet, this would be 19% (at 370 calories) to 40% (at 800 calories) of someone’s caloric intake.

The recommendation I give in my Label Reading talk is to limit consumption of all concentrated caloric sweeteners to no more than 5% of calories which for someone consuming 2000 calories is 100 calories per day which is 25 grams or about 2 tablespoons. The only exception I give is that if someone has elevated TGs, or at risk for CVD, then they may want to avoid those higher in fructose.

Therefore, limit your consumption of all refined and/or concentrated sweeteners and if heart disease, elevated triglycerides, insulin resistance, diabetes and/or weight are concerns of yours, avoid the ones higher in fructose, especially agave.

Reader comments.

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References

1. Br J Nutr. 2008 Nov;100(5):947- 52. Consumption of fructose-sweetened beverages for 10 weeks increases postprandial triacylglycerol and apolipoprotein- B concentrations in overweight and obese women.

2. Am J Clin Nutr. 2008 Nov;88(5):1419- 37. Fructose consumption and consequences for glycation, plasma triacylglycerol, and body weight: meta-analyses and meta-regression models of intervention studies.

3. J Agric Food Chem. 2009 Jul 31. [Epub ahead of print] Formation of Hydroxymethylfurfural in Domestic High-Fructose Corn Syrup and Its Toxicity to the Honey Bee (Apis mellifera ).

4. Advanced Glycation End Products and Nutrition Physiol. Res. 51: 313-316, 2002

5. Environ Health. 2009 Jan 26;8:2. Mercury from chlor-alkali plants: measured concentrations in food product sugar.

6. Total Antioxidant Content of Alternatives to Refined Sugar, JADA. Volume 109, Issue 1, Pages 64-71 (January 2009).