Category Archives: disease

Don’t Drink the Agave-Sweetened Kool-Aid Part II: What’s Wrong With Any High-Fructose Syrup

Who knew agaves grew in so many different flavors?

In the first post on agave nectar, I focused primarily on why it’s no more “natural” than high-fructose corn syrup, which is a delicious irony given how both sweeteners tend to be portrayed. But that isn’t necessarily a reason to avoid agave nectar. “Natural” is at best an imperfect heuristic for healthiness or environmental friendliness, and has no inherent relationship with deliciousness. But, as I also suggested in the first post, agave nectar is certainly no better health-wise than other sources of sugar, and the fact that it’s much higher in fructose than most sweeteners (70-90% vs. ~50%) gives me reason to believe it may actually be worse for your health than sucrose or HFCS-55.

So Don’t Drink the Agave-Sweetened Ketchup Either. Because That Would Be Gross.GRANOLA-WASHING

Perhaps the most baffling thing is how many people seem to think agave nectar doesn’t count as sugar. For example, the rave review of Wholemato Organic Agave Ketchup in Men’s Health, contrasts it with the “liquid candy” that is HFCS. And then implies that the even-higher-fructose agave-sweetened condiment is healthier than “fatty” butter (it’s like someone at Men’s Health was specifically trying to give me apoplectic fits): 

This ketchup forgoes the high-fructose corn syrup and uses agave nectar, preserving sweetness without clobbering your fries or hot dog with liquid candy…. Slather it on your sweet potatoes as an alternative to a fatty slab o’ butter.

Note: The review is only available on the Wholemato site because the “read more” link is broken, but I’m not inclined to think it’s a fabrication as the other links on their “buzz” page are legit and you can find nearly-identical, equally-apoplexy-inducing claims about Wholemato Ketchup at The Kitch’n, Girlawhirl, i like granola, and Well Fed Man, among others.

There are also people who claim to have given up sugar, but who still eat agave nectar. Some excerpts from the comment thread on Nicole MacDonald’s resolution to give up sugar in 2010:

Jennifer: I went sugar-free at 16 to help my psoriasis & still don’t have it, 8 years later .
I don’t miss it at all. If I want to make a cake or anything I will use agave nectar … you realise there are so many interesting & alive foods out there you can enjoy without compromising your health!! xx

Nicole: I have to admit that in the first few weeks I baked a lot using ingredients like honey, agave and brown rice syrup. Cookies are my favorite to make, and I have a long list of recipes on my blog to the right. I also drank a lot of flavored tea with honey added and that seemed to cure some of my cravings.

Beth: I stopped eating sugar last year and its worked out pretty well. As long as I can have natural sugars which are found in fruits, then I’m totally satisfied.

Not All Things That Occur Naturally In Fruit Should Be Consumed In Quantity. Like Cyanide.

Beth is certainly not alone in thinking that “sugars which are found in fruits” are healthier than other sugars. People are frequently resistant to the idea that fructose might be unhealthy because, as the name so conveniently reminds them, it’s found in fruit. Or, if they’ve been sold on the idea that HFCS is poison and fructose has something to do with that, they sometimes suggest that there must be different kinds of fructose. Take, for example, the comment by Dave on this post by ThursdaysGirl, which expressed some reservations about agave nectar:

[. . .] you say Agave is 70% fructose, ok, so that means that means a teaspoon of Agave (about 4 grams) has about 2.8 grams of fructose… Hmmm, a small tomato has about 2.6 grams of fructose in it, the same as a carrot!… so, by your ridiculous logic, you should run away from tomatoes and carrots as fast and as far as you can! OMG, never eat another tomato! And don’t even get me started on Apples!

Remember, HFCS, regardless of what the lying chemists say, is not a natural source of Fructose. It is a man made molecule. It is illegal to call High Fructose Corn Syrup “All Natural”. I wonder why… Agave can be found both All Natural and Organic!!! Small amounts of Fructose actually help metabolize Glucose better, plus its low glycemic, has natural inulin fiber which is amazingly beneficial [. . . .]

I would trust the Mayo Clinics recommendations as regards to High Fructose Corn Syrup… it is poison. But really, Apples, Carrots, Tomatoes etc all bad for you? Stop it.

It’s actually not illegal to call HFCS “natural.” The FDA has been notoriously unwilling to define “natural” aside from the essentially meaningless distinction between “artificial” and “natural” colors and flavors—which Eric Schlosser talks about extensively in Fast Food Nation (pp. 121-131). As of July 2008, HFCS is “natural” for the purposes of food labeling. You can read all about the ongoing legal debates here. However, that hasn’t stopped people from trying to differentiate “natural” fructose, like the stuff in fruit, from “chemically-produced” fructose, like the stuff in HFCS. The problem is that they can’t seem to agree which side the fructose in agave nectar is on.

As you might expect, the agavevangelists are on the side of “natural.” According to Kalyn’s Kitchen Picks :

It’s been a long time since I discovered a new product that rocked my world in the way agave nectar has done…. The sweet taste in agave nectar comes from natural fructose, the same sweetener found in fruit (not to be confused with high fructose corn syrup which has chemically produced fructose.)

On the other side, there’s Rami Nagel, whose Natural News article been widelycirculated and cited by people on both sides of the agave nectar debate. According to Nagel, agave nectar is composed of bad, man-made “fructose,” which he claims actually has a completely different chemical formula from the sugar in fruit, which he calls “levulose”:

We all know that the chemical formula for water is H2O: two hydrogens and one oxygen. The opposite would be O2H, which is nothing close to water. Likewise, man-made fructose would have to have the chemical formula changed for it to be levulose, so it is not levulose. Saying fructose is levulose is like saying that margarine is the same as butter. Refined fructose lacks amino acids, vitamins, minerals, pectin, and fiber. As a result, the body doesn’t recognize refined fructose. Levulose, on the other hand, is naturally occurring in fruits, and is not isolated but bound to other naturally occurring sugars. Unlike man-made fructose, levulose contains enzymes, vitamins, minerals, fiber, and fruit pectin. (Similar claims here and here)

However, levulose is just an alternate name for fructose. A search for “levulose” on Wikipedia automatically redirects to their fructose entry. ChemBlink claims they’re synonyms with the exact same molecular formula and structure:

levulose/fructose...not quite as catchy as tomayto/tomahto 

And even the earliest examples from the OED reveal that the terms are completely interchangeable: 

1897 Allbutt’s Syst. Med. III. 386 Cane sugar is partly left unchanged, partly converted into glucose and lævulose. 1902 Encycl. Brit. XXII. 721/1 Glucose and fructose (lævulose)the two isomeric hexases of the formula C6H12O6 which are formed on hydrolysing cane sugar.

With “levulose” eventually giving way to “fructose” by the the 1970s:

1974 Nature 10 May 194/3 Although it is true that some bacteriologists are extremely conservative in the names they use for carbohydrates, surely nobody now uses ‘levulose’…in preference to ‘fructose’ these days.

A PubMed search for “levulose” also turned up 30,398 articles about (surprise!) fructose. The twenty articles that actually had “levulose” in the title were almost all translations, mostly from German.

So no, there is no difference between “naturally occurring” and “chemically-produced” fructose (and if the fructose in HFCS is the latter, so is the fructose in agave). Nonetheless, Dave and Rami Nagel are both at least partially correct. Fructose/levulose may not contain enzymes, vitamins, minerals, fiber, and fruit pectin, but the fruits that contain levulose/fructose certainly do. And there’s no reason to believe that eating a small amount of agave nectar, say a teaspoon, with similar amounts of fiber, protein, and other nutrients as would be found in a tomato or carrot would have a different or worse effect on the body than the vegetables themselves.

Fructose and Your Liver

Just because fructose isn’t necessarily bad for you in the amounts present in most fruits and vegetables, that doesn’t mean it’s a healthier substitution for other sugars. The evidence from studies on humans is still pretty scant. However, in a 2008 study where 23 subjects got 25% of their caloric intake from either fructose-sweetened or glucose-sweetened beverages for 10 weeks, the subjects who drank the fructose-sweetened drinks showed signs of decreased insulin sensitivity (a sign of diabetes) and increased fat in their abdominal regions, especially around their heart and liver, which is associated with cardiovascular disease (here’s the study itself or a translation from WebMD).

We’ve known for over 50 years that fructose is metabolized differently than glucose. Once it enters the body, it’s taken up by the liver, so it doesn’t raise blood sugar levels as much as glucose. It bypasses the step that insulin regulates, so diabetics can digest fructose about as well as non-diabetics. Which initially sounds good, especially for diabetics; however, more recently, fructose has been shown to have the same effects as alcohol on the liver:

I won't pretend to understand everything that's going on here, except that it illustrates the various processes and feedback mechanisms that cause fatty liver disease. From “Fructose Takes a Toll” in the August 2009 Hepatology (login required)

As a recent article in Physiological Review notes:

Fructose was initially thought to be advisable for patients with diabetes due to its low glycemic index. However, chronically high consumption of fructose in rodents leads to hepatic and extrahepatic insulin resistance, obesity, type 2 diabetes mellitus, and high blood pressure. The evidence is less compelling in humans, but high fructose intake has indeed been shown to cause dyslipidemia and to impair hepatic insulin sensitivity.

So while probably harmless in small amounts, it’s certainly not a “healthy” sugar or a free pass to eat sweet things without potential/likely health consequences.

I’ll do a follow-up eventually about the claim that you can use less of it because it’s sweeter. There are lots of conflicting claims about how much sweeter it is and how much less of it you use that I’m still trying to sort out. So far, I’m not at all convinced that the small caloric benefit is a reasonable trade-off for the risks of increased fructose consumption. I’ll also address one final defense: at least in some applications and to some palates, agave nectar may taste better. I admit to being a little skeptical, but a friend has promised to arrange a blind taste-test of mint juleps made with agave nectar, simple syrup, and a 50-50 agave nectar/brown rice syrup blend. That won’t happen until the national day of mint julep drinking, which falls on May 1, 2010 this year. So, until then, I’m going to take a little break from reading and writing about agave nectar.

Things That Won’t Kill You Volume 4: Saturated Fat, Part I

I know this is misleading because lard is mostly unsaturated, but it's been one of the major icons of "bad" fat and also, how graet is this image? from

This is probably going to be an even harder sell than MSG, but I swear I’m not just trying to be contrary. It’s true that all the major sources of public health and nutrition advice, including the Harvard School of Public Health, Mayo Clinic, CDC, and American Heart Association continue to refer to saturated fats as "bad fats" and suggest that people avoid them as much as possible, limit them to <7-8% of their total caloric intake, and replace them with "good," i.e. unsaturated fats, whenever possible. It’s also true that there are a few studies that suggest that increased saturated fat consumption is correlated (albeit weakly) with cardiovascular disease (CVD).

However, many other studies have found no increase in CVD associated with saturated fat consumption. And several recent review articles have concluded that the evidence for a connection between saturated fat consumption and CVD is inconsistent, insufficient or nonexistent.

There are basically three things that have convinced me that saturated fat isn’t independently responsible for heart disease or death:

1) groups of people who eat vastly more saturated fat than most Americans frequently have lower rates of CVD—or no apparent CVD at all

2) the study that first inspired many people to think saturated fat was a bad thing had a lot of obvious flaws and has been thoroughly discredited

3) there’s no good evidence that the proposed mechanism actually works—briefly: saturated fat supposedly causes heart disease by raising serum cholesterol levels because cholesterol is what clogs arteries and causes heart attacks and strokes, but serum cholesterol turns out to be a really poor predictor of CVD 

1) The French (and Polynesian and Melanesian and Masai and Fulani and Sri Lankan) Paradox 

photo by Arun Ganesh most confounding phenomenon for the theory that saturated fat consumption causes heart disease (sometimes called the lipid hypothesis or lipid-heart hypothesis or diet-heart hypothesis) is the virtual non-existence of CVD in multiple populations that eat way more saturated fat than most Americans. This has primarily been documented in the Pacific islands where coconuts, which are very high in saturated fat, are a staple food. For example, before the 1970s, the inhabitants of the island Tokelau got an estimated 55% of their calories from saturated fat, but heart disease was virtually unknown (according to Gary Taubes and Stephen Guyenet; notably, since their diet has shifted to include less saturated fat but more sugars and refined carbohydrates, many health indicators have worsened).

Many proponents of "natural" foods have already embraced the coconut as a source of "healthy" fat, but the confounding phenomenon isn’t unique to coconut-eaters. The Masai of Kenya and Tanzania and Fulani of Nigeria, whose traditional diet is composed primarily of cow’s milk, meat, and blood and estimated to be 33% saturated fat, also had virtually no incidence of CVD—or didn’t until they started eating refined carbohydrates. Red meat and dairy sources of saturated fat are about as classically "unhealthy" as you can get, and yet don’t necessarily cause heart attacks and death.

The differences can’t be attributed, at least entirely, to genetics, and not just because the phenomenon is consistent among so many far-flung populations. The Masai are known to be highly genetically diverse due to conflict/intermarriage, and all of the populations have experienced changes in their health as their diets have changed.

Nor are the changes likely due to higher activity levels, cyclical feast and famine, average lifespan, or the absence of other risk factors like cigarette use in these populations. A 1993 study of diet and health in Kitava, the Trobriand Islands, and Papua New Guinea found that Kitavans get an average of 17% of their calories from saturated fat (compared to about 10% for Americans or the <7% recommended by the AHA), tend to be about as active as moderately active Swedes, and have virtually no experience of food scarcity or shortage. Furthermore, 75% of the population smokes. Nonetheless, stroke and heart attack basically don’t exist even among the elderly there, and their fasting insulin levels are significantly lower than Swedes’ in every age group.  

Another potentially confounding fact that some low-carb proponents point to is the alleged decline in the average American’s consumption of saturated fat. It’s true that the consumption of some primary sources of saturated fat like butter and lard declined for most of the 20th Century; however, per capita red meat consumption grew until the 1970s, and according to the USDA, the proportion of saturated fat in the U.S. food supply has remained pretty steady for the last century. What is clear, at least, is that increasing rates of cardiovascular disease were not caused by increasing per capita consumption of saturated fats.

So why the hell have the institutions we trust to tell us how our diets affect our health spent the last half-century trying to convince us that saturated fat clogs your arteries, causes heart attacks, and might kill you?

2) It All Began With Some Falsified Data January 13, 1961 cover of Time magazine

I know, I sound like a climate change skeptic, but this is way more blatant than some sketchy e-mails.

The research that first convinced many Americans and public health institutions like the AHA that saturated fats cause heart disease was the Seven Countries Study led by Ancel Keys. Keys and his colleagues carried out surveys of men (only men because the rate of CVD in women was considered too low to merit attention) in eighteen rural regions in Italy, the Greek Islands, Yugoslavia, the Netherlands, Finland, Japan, and the U.S. The regions were supposedly chosen because they were areas with stable and widely-contrasting diets. The researchers asked the men about their eating habits, performed chemical analysis on meals prepared by randomly-selected families, and compared their findings to the rate of disease and death in the different populations, with special attention given to CVD and "risk factors" like serum cholesterol levels. They concluded that higher levels of dietary saturated fat cause elevated serum cholesterol and heart disease. The especially low rates of CVD in Crete, despite relatively high proportions of dietary fat, were a large part of the impetus behind the "Mediterranean Diet" and the idea that olive oil is nutritionally sacrosanct.

However, as many people later pointed out, it seems more than coincidental that Keys only included regions where both saturated fat consumption and heart disease were high or where they were both low. Apparently, data was available for a number of other countries (anywhere between 15 and 27, according to various critics), perhaps most notably France, which would have been just as easy to study as Finland and Japan. Keys seemingly ignored, or systematically excluded, all confounding data from his analysis.  

Even for the countries that were included, according to statistician Russell H. Smith:

The dietary assessment methodology was highly inconsistent across cohorts and thoroughly suspect. In addition, careful examination of the death rates and associations between diet and death rates reveal a massive set of inconsistencies and contradictions…. It is almost inconceivable that the Seven Countries study was performed with such scientific abandon. It is also dumbfounding how the NHLBI/AHA alliance ignored such sloppiness in their many "rave reviews" of the study…. In summary, the diet-CHD relationship reported for the Seven Countries study cannot be taken seriously by the objective and critical scientist.

The problem seems to be that Keys had already decided that saturated fat was the problem. According to the Time magazine cover article (click the picture to read it), Keys had treated a heart disease patient with large knobs of what turned out to be cholesterol under his skin and very high serum cholesterol. When he put that patient on a low-fat diet, his cholesterol went down. Since cholesterol is what clogs arteries and causes heart attacks, and foods high in saturated fat are often also high in cholesterol, Keys concluded that the high rates of heart disease in American men were caused by the saturated fat and cholesterol content of their diets. In the Seven Countries study, he set out to prove that theory (as opposed to testing it).

Fifty years of subsequent research have not found a consistent or reliable correlation between saturated fat consumption and heart disease or death. This entry got a little out of hand, so I split it into a couple of parts. More coming soon on dietary cholesterol and the dreaded LARD, neither of which, it turns out, are likely to kill you or even probably hurt you a little bit. Also, an epilogue of sorts on trans-fats, which might actually kill you.