After much thought, I have decided that it is time for me to move on from this space. When I started blogging just over three years ago, life was very different--I was pregnant with my first child and had a lot more free time on my hands. Now, I not only have two little ones to juggle, but I've discovered new passions that are keeping me away from my computer screen--guiding me out into the world, enjoying each lovely moment with my young children. Now, I can be found not in cyberspace, but at home behind the sewing machine, or in the backyard dreaming up next year's garden, or peeking out the bedroom window as my baby boy squeaks with delight at the chickadees flitting about the plum tree, or at the kitchen counter tearing kale for dinner with my almost-3-year-0ld. These days are full to bursting with the joyous, messy, wonderful reality that is raising children. Although veganism remains very important to us and our family, my creative passions are now all wrapped up in parenting, a job that I have found ever more fulfilling since discovering Waldorf education (if you are interested, here are some parenting websites I love). With this happily busy life, my blogging has fallen by the wayside, and so, it is time for me to say goodbye.
I have enjoyed blogging and have met some wonderful friends because of it, connections for which I am profoundly grateful. I also have to thank my amazing husband, who has always been Vegan Dietitian's #1 fan, for his support (he continues to blog about tea here). If you have come to this page searching for a vegan dietitian's take on nutrition issues, check out Ginny Messina's amazing blog, The Vegan RD. Who knows, I may someday return to blogging here or elsewhere... but for now I am happy to take a break.
Thank you, everyone, for reading! Wishing all of you health, happiness, and many wonderful plant-based meals.
Saturday, January 1, 2011
Tuesday, November 16, 2010
Sweetener Glossary
After my earlier post on agave nectar, you may be wondering which sweetener is really the best to use. Most dietitians would tell you that “sugar is sugar” and that the best thing to do is to keep your consumption of sugar—no matter the type—at a minimum. While this is largely true, I feel that it is important to consider the methods and degree of processing used to make the sweeteners that we enjoy; this can help us make better decisions when faced with the vast array of options available to us today.
After all the research I have done as a dietitian, I believe that the healthiest diet is one that is based on foods as close to their natural state as possible. Sugars don’t really fit this bill. Sure, there are natural sweeteners that don’t involve much processing, but almost all of the items listed below (with the exception of honey and date sugar) are processed in some way. Nonetheless, most of us take great pleasure in enjoying sweet treats from time to time, and these occasional indulgences will not have a huge impact on health.
The best sweeteners tend to be those that are the least processed. Whereas other food products, such as flour, lose significant amounts of nutrients during processing, the amounts of nutrients in sugar (even relatively unrefined products) aren’t going to make a real nutritional difference. You’d have to eat very large quantities in order get a significant amount of the healthful nutrients naturally present in sugar sources--and relying on sugar to get nutrients is certainly not recommended! Really, the main nutrient sugars provide is calories--something that most of us aren't deficient in--and since all sugars have roughly the same amount of calories per gram, they are generally considered nutritionally equivalent. However, there is some research indicating that less-processed sugars have greater antioxidant potential. Still, sugar will never be a health food and should be used sparingly.
So, without further ado (and just in time for the holidays!), I present to you a handy glossary of sweeteners, from the least to the most processed.
Unprocessed Sweeteners
Honey: Though this sweetener is not technically vegan, it is undoubtedly the least processed sweetener and, not long ago, was the only sweetener available (aside from raw sugarcane). In my opinion, the decision to use or not to use honey should be up to each individual vegan. (See this Slate article for an interesting discussion of the vegan honey debate.) Regardless, there are plenty of plant-based sweeteners to choose from if you decide not to use honey.
After all the research I have done as a dietitian, I believe that the healthiest diet is one that is based on foods as close to their natural state as possible. Sugars don’t really fit this bill. Sure, there are natural sweeteners that don’t involve much processing, but almost all of the items listed below (with the exception of honey and date sugar) are processed in some way. Nonetheless, most of us take great pleasure in enjoying sweet treats from time to time, and these occasional indulgences will not have a huge impact on health.
The best sweeteners tend to be those that are the least processed. Whereas other food products, such as flour, lose significant amounts of nutrients during processing, the amounts of nutrients in sugar (even relatively unrefined products) aren’t going to make a real nutritional difference. You’d have to eat very large quantities in order get a significant amount of the healthful nutrients naturally present in sugar sources--and relying on sugar to get nutrients is certainly not recommended! Really, the main nutrient sugars provide is calories--something that most of us aren't deficient in--and since all sugars have roughly the same amount of calories per gram, they are generally considered nutritionally equivalent. However, there is some research indicating that less-processed sugars have greater antioxidant potential. Still, sugar will never be a health food and should be used sparingly.
So, without further ado (and just in time for the holidays!), I present to you a handy glossary of sweeteners, from the least to the most processed.
Unprocessed Sweeteners
Honey: Though this sweetener is not technically vegan, it is undoubtedly the least processed sweetener and, not long ago, was the only sweetener available (aside from raw sugarcane). In my opinion, the decision to use or not to use honey should be up to each individual vegan. (See this Slate article for an interesting discussion of the vegan honey debate.) Regardless, there are plenty of plant-based sweeteners to choose from if you decide not to use honey.
Date sugar: Date sugar is just dehydrated, ground dates. Thus, it is the only true “whole food” sweetener listed here. This can be used in baking, but isn’t good for sweetening beverages as it won’t dissolve. You can make a date syrup by boiling dates in water—though of course this would remove the fiber and make it more equivalent to maple syrup.
Sweeteners with Little Processing
Blackstrap molasses: To make molasses, the sugar cane plant is harvested and its juice is extracted. It is then boiled in order to concentrate and crystallize the sugar, which is then removed. The result of the first boiling is “first molasses.” Second molasses is created from a second boiling and sugar extraction, and has a less-sweet, slightly bitter taste. The third boiling makes strong-flavored but relatively nutritious blackstrap molasses.
Unrefined dark brown sugar (such as Muscovado sugar): This is produced from the first crystallization of the sugar cane. Some conventional brown sugars are made from refined beet sugar with molasses added. You can avoid this by making sure the package specifies “cane sugar,” or by buying organic.
Maple syrup: This lovely, time-tested sweetener is made from the sap of certain maple trees. This sap is tapped and then concentrated by heating it to evaporate the water.
Organic sugar/Evaporated cane juice/Raw sugar: This is sugar cane juice that has been concentrated and crystallized. It is unrefined. Apparently, however, the FDA does not regulate the term, so degree of processing could vary between companies. Also, organic sugar cannot use chemicals to bleach and filter the product, or use charcoal made from animal bones for filtration (an important consideration for vegans).
Fruit juice concentrate: This is a rather sneaky type of sugar used especially for beverages, but also for other processed foods. It may sound good and natural, and it does come from fruit originally, but it has been purified so that none of the goodness of the fruit remains. Think of this as sugar.
Sweeteners with Intermediate Processing
Corn syrup: Made from treating corn starch with an enzyme to break the starch into sugar (see previous post)
Agave nectar: Made from treating agave plant with heat and/or enzymes to break down the starch into sugars (see previous post)
Brown rice syrup: This syrup is derived by culturing cooked rice with enzymes to break down the rice’s starches, then straining off the liquid and reducing it by cooking to the desired consistency.
Highly Processed Sweeteners (Avoid!)
Refined sugar: There are many reasons besides health concerns to avoid refined sugar. For example, much of the sugar grown in the U.S. is produced from genetically modified sugar beets, and many herbicides and pesticides are sprayed on conventional sugar plants. Farmers who produce sugar in developing countries generally are not paid a living wage for their work. And some conventional sugar still uses bone char during processing. So stick with organic, fair trade sugar. Sure, it's more expensive, but that may help you eat less.
Conventional brown sugar: Unless specified as cane sugar, this is often made by coating refined beet sugar with molasses. (If you wash the crystals in water, the molasses will wash off, leaving you with white sugar!) Best to buy organic.
High Fructose Corn Syrup: Made by treating corn syrup with enzymes to change the sugar content. Not inherently evil, but still best avoided (see previous post).
A Word on Non-Nutritive/Artificial Sweeteners
I am not a proponent of consuming artificial sweeteners, such as Splenda, NutraSweet, or Equal. Despite FDA assurance that these are safe, there are other reasons to avoid them, chief among them that these artificial chemicals have not been a part of our diets for very long and thus we may not be aware of long-term health effects. There is some evidence indicating that the perceived sweetness of these beverages may actually increase intake at future meals. A recent Danish study showed a link between diet soda and preterm delivery. Some studies have also shown that diet soda consumption is correlated with obesity—but this does not show cause and effect. (For example, it may be that obese individuals are drinking more diet soda in order to control their weight, rather than it causing weight gain in the first place.)
Stevia, which is a naturally derived non-nutritive sweetener, would also fall into this category. Though stevia has been used traditionally in South America, it was only used in its whole leaf form (either fresh, dried, or in a powder). However, most of the widely available stevia powder (and the stevia now being used in processed foods as Truvia or PureVia) is the purified extract of one of the sweet compounds from the stevia leaf. This has only recently been approved by the FDA, and there haven't been many studies done on its safety in humans. As with the above sweeteners, if you are going to use stevia it is best to use a whole-leaf product (you can even try growing your own) since this is the closest to its natural state.
Really, though, it would be best to avoid these and develop a taste for unsweetened beverages (with a little lemon, lime, cucumber or mint for flavor if desired). As is true for caloric sweeteners, the less sweet stuff you eat and drink, the less you will crave.
Tuesday, September 21, 2010
"Cheesy" Kale Chips
Kale chips seem to be all the rage lately... and I am certainly not one to miss out on any trend involving my favorite veggie! Though I occasionally buy kale chips to snack on (our favorite being Blessings Alive and Radiant Foods' "Quite Cheesey" flavor), the high price tag and limited availability made them a rare treat. For some reason I hadn't attempted to make them at home until recently... and after discovering how wonderful and easy they are, I promptly decided that our fall garden space would be dedicated solely to kale. These are absolutely delicious and, might I add, very kid-friendly (well, I admit they were tested only on one kid in this household who happens to love kale... but the mild flavor and crunchy texture should please even the most hesitant veggie eater). My little helper also enjoyed tearing up the leaves for the chips, and even ate a few pieces raw (yes, her mama is so proud!).
Ideally these would be made in a dehydrator, but since I don't have one (yet!) I baked them at low temperature in the oven. Thanks to our pal Jon for passing on the recipe he developed for the tasty cashew cheese topping!
"Cheesy" Kale Chips
Ingredients:
1 bunch kale (any variety works)
Topping:
Ideally these would be made in a dehydrator, but since I don't have one (yet!) I baked them at low temperature in the oven. Thanks to our pal Jon for passing on the recipe he developed for the tasty cashew cheese topping!"Cheesy" Kale Chips
Ingredients:
1 bunch kale (any variety works)
Topping:
1 cup raw cashews
Juice of 1/2 lemon
1/4 cup nutritional yeast
1 red bell pepper, raw
1/2 tsp sea salt
Preparation:
Preparation:
- Preheat oven to 200 degrees.
- Remove stems from kale and tear into small, chip-sized pieces. Set aside.
- Combine all topping ingredients in a food processor, and blend until creamy.
- In a large mixing bowl, mix the cashew cheese with the kale. You want to coat each leaf with the topping and avoid large clumps, so it's best to roll up your sleeves and work with your hands.
- Spread kale in a single layer on a baking sheet (you will probably need two baking sheets per bunch of kale) and put into the oven.
- Begin checking the chips after about an hour and a half. You want them nice and crispy (though they are still delicious even if they're a bit chewy). This may take 2 hours or longer. You could bake at a higher temperature (though I'd recommend staying below 300) to speed the process, but would have to be more vigilant about removing them as they turn crisp, since they are more apt to burn.
- Store crispy chips in an airtight container. If you have any chewy ones that didn't fully dehydrate, it's best to just eat them... otherwise the rest will become chewy. Enjoy!
Sunday, August 22, 2010
Agave Nectar
Over the past few years, agave nectar (also known as agave syrup) has become a very popular sweetener. Due to its low glycemic index, it is widely assumed to be healthier than sugar, and its versatility and flavor have made it a common vegan substitute for honey. But is agave nectar really as healthy as it is claimed to be?
Agave nectar is made by extracting juice from the core or stalk of the agave plant (depending on which species of the plant is used). Because this juice naturally occurs as a soluble fiber (inulin), it must be processed using heat and/or enzymes in order to break the inulin down into its component sugars. If the juice of certain species is fermented instead, it will become tequila.
Inulin is made mostly of fructose, so agave nectar is extremely high in fructose. Content varies from brand to brand, but most are somewhere between 70 and 90% fructose (much higher than even high fructose corn syrup, which is only 55% fructose). Because it is mostly fructose, agave nectar doesn't have an immediate effect on blood sugar, which is why it classifies as a low-glycemic sweetener. However, as mentioned in my high fructose corn syrup (HFCS) post, the research on fructose indicates that this comes at a cost. If agave consumption is high enough, it could have deleterious effects on health similar to those attributed to HFCS, including elevated blood lipids and insulin resistance.
I was unable to find any studies on agave nectar and health outcomes; since it has only recently become popular, it hasn't really been studied. However, I did find one study comparing antioxidant levels of different sugars, which indicated that agave nectar had very low antioxidant activity, similar to refined sugar and corn syrup (1). In contrast, molasses was fairly high and maple syrup, brown sugar and honey had intermediate levels of antioxidants.
Though agave nectar has been marketed as a safe sweetener for diabetics, there have been some legitimate concerns of its safety in this population. In addition, I have read several reports of certain (unnamed) brands "watering down" their agave with corn syrup or HFCS, since it is so much cheaper (2)!
There is also some debate over whether "raw" agave nectar truly is raw, since most manufacturers use heat at some point of the processing. (See this post to find out more about the processing methods used by specific companies.) Some companies produce agave nectar that is heated to no more than 120 degrees, but the larger question remains: should a sweetener that needs this level of processing should be included in a raw diet? Of course, this is a question that each individual needs to answer for themselves. For those looking for other raw alternatives, see the excellent suggestions at the end of this article (including the healthiest sweetener of all, ripe fresh fruit).
So, should you use agave nectar at all? Like any sweetener, it shouldn't be eaten in unlimited quantities. In fact, I wouldn't recommend using agave as your only source of added sugar, because there has been fairly convincing research that large intakes of fructose can be harmful. In addition, whether or not agave nectar is a "natural" sweetener is open to interpretation. It is subjected to a fair amount of processing (similar to that of corn syrup). All that being said, a small amount of agave nectar in the context of a healthy plant-based diet low in added sugars probably isn't too harmful. But my research has led me to believe that agave nectar actually isn't any healthier than refined sugar.
References
1. Phillips KM, Carlsen MH, Blomhoff R. Total antioxidant content of alternatives to refined sugar. Journal of the American Dietetic Association 2009; 109 (1):64-71.
2. Johannes L. Agave Syrup May Not Be So Simple. Wall Street Journal, October 27, 2009.
Agave nectar is made by extracting juice from the core or stalk of the agave plant (depending on which species of the plant is used). Because this juice naturally occurs as a soluble fiber (inulin), it must be processed using heat and/or enzymes in order to break the inulin down into its component sugars. If the juice of certain species is fermented instead, it will become tequila.
Inulin is made mostly of fructose, so agave nectar is extremely high in fructose. Content varies from brand to brand, but most are somewhere between 70 and 90% fructose (much higher than even high fructose corn syrup, which is only 55% fructose). Because it is mostly fructose, agave nectar doesn't have an immediate effect on blood sugar, which is why it classifies as a low-glycemic sweetener. However, as mentioned in my high fructose corn syrup (HFCS) post, the research on fructose indicates that this comes at a cost. If agave consumption is high enough, it could have deleterious effects on health similar to those attributed to HFCS, including elevated blood lipids and insulin resistance.
I was unable to find any studies on agave nectar and health outcomes; since it has only recently become popular, it hasn't really been studied. However, I did find one study comparing antioxidant levels of different sugars, which indicated that agave nectar had very low antioxidant activity, similar to refined sugar and corn syrup (1). In contrast, molasses was fairly high and maple syrup, brown sugar and honey had intermediate levels of antioxidants.
Though agave nectar has been marketed as a safe sweetener for diabetics, there have been some legitimate concerns of its safety in this population. In addition, I have read several reports of certain (unnamed) brands "watering down" their agave with corn syrup or HFCS, since it is so much cheaper (2)!
There is also some debate over whether "raw" agave nectar truly is raw, since most manufacturers use heat at some point of the processing. (See this post to find out more about the processing methods used by specific companies.) Some companies produce agave nectar that is heated to no more than 120 degrees, but the larger question remains: should a sweetener that needs this level of processing should be included in a raw diet? Of course, this is a question that each individual needs to answer for themselves. For those looking for other raw alternatives, see the excellent suggestions at the end of this article (including the healthiest sweetener of all, ripe fresh fruit).
So, should you use agave nectar at all? Like any sweetener, it shouldn't be eaten in unlimited quantities. In fact, I wouldn't recommend using agave as your only source of added sugar, because there has been fairly convincing research that large intakes of fructose can be harmful. In addition, whether or not agave nectar is a "natural" sweetener is open to interpretation. It is subjected to a fair amount of processing (similar to that of corn syrup). All that being said, a small amount of agave nectar in the context of a healthy plant-based diet low in added sugars probably isn't too harmful. But my research has led me to believe that agave nectar actually isn't any healthier than refined sugar.
References
1. Phillips KM, Carlsen MH, Blomhoff R. Total antioxidant content of alternatives to refined sugar. Journal of the American Dietetic Association 2009; 109 (1):64-71.
2. Johannes L. Agave Syrup May Not Be So Simple. Wall Street Journal, October 27, 2009.
Friday, August 20, 2010
High Fructose Corn Syrup
Possibly the most contentious sweetener of our times is high fructose corn syrup (HFCS). This ubiquitous sweetener makes its appearance in many processed foods--from the obvious (soda and cookies) to the seemingly innocuous (ketchup, salad dressing, crackers). While there has been a huge public outcry against this sweetener, industry groups (especially the Corn Refiners Association, or CRA) insist that HFCS is the same as sugar, even going so far as to call it a "natural" sweetener. So, is HFCS really the root of all our health problems, or is it merely a convenient, economical sweetener with no adverse effects?
Corn syrup is made by breaking up corn starch into its component sugars (mostly glucose), which yields the standard corn syrup available in any grocery store. High fructose corn syrup is made when corn syrup undergoes an additional enzymatic reaction to convert its glucose into fructose, which is sweeter than sugar. This is then mixed with pure glucose in varying ratios for different food industry products; the most common form is HFCS-55, which is about 55% fructose and 45% glucose. On the other hand, sugar (sucrose) is made of 50% glucose and 50% fructose (see previous post for sugar chemistry overview). Therefore, the ratios of glucose and fructose are not all that different in the two sweeteners; the term "high fructose" is a bit of a misnomer, and is certainly not interchangeable with pure fructose.
With all that in mind, let's take a look at some of the claims against HFCS and the evidence behind them.
High fructose corn syrup is responsible for the obesity epidemic. This claim originated from the fact that the use of HFCS as a sweetener rose along with the increase in obesity over the last 20 years. However, correlation does not prove causation, and obesity is a complex condition that arises from many factors. Blaming it on a single ingredient oversimplifies the issue. Rather, the obesity epidemic seems to have stemmed from a "toxic food environment," of which HFCS-containing soft drinks are certainly a part, but the incessant food advertising, the ubiquity of fast food restaurants, the subsidization of corn and soybeans (processed to produced HFCS and soybean oil, respectively), and the high cost of healthy foods like fruits and vegetables also contribute to this. Add to this the decrease in physical activity as people become more sedentary, and you have a perfect storm. In so far as HFCS-containing beverages and foods are a contributor to this, they could be considered one of the causes of obesity, but not the only cause.
That being said, there are several underlying biochemical reasons that would support the link between HFCS and obesity. Most importantly, fructose undergoes a different biochemical pathway than glucose; it must be processed in the liver. Unlike glucose, which can feed the body's cells directly, fructose either goes into storage in the liver, or can be converted into fat (triglycerides) for storage or for transport to other cells in the body to use as energy. Since it goes through different pathways, fructose is not regulated by insulin and does not have a direct effect on blood sugar. This may come at the price of elevating triglycerides, however. There is evidence that high intakes of fructose over the long term can lead to insulin resistance and have negative effects on blood lipids (1). Again, this link has been found with pure fructose, so the industry argues that because HFCS is only 5% higher in fructose compared to sugar, these detrimental effects of fructose do not apply to their product.
However, it stands to reason that if intakes are significant enough (and unfortunately, intakes of added sweeteners are extremely high in the U.S), this difference could become important. In fact, total fructose intake increased nearly 30% between 1970 and 2000 (2)--an increase that could have only come from the concomitant increase in the use of HFCS in processed foods. (Most Americans don't come close to meeting the recommended dietary intake of fruit, which is naturally high in fructose, and while honey and agave nectar are also high in fructose, these sweeteners are nowhere near as common as HFCS.) Thus, concerns for HFCS having a detrimental effect on blood lipids seem to be legitimate.
It has also been suggested that HFCS increases appetite, since fructose has different effects from sugar on the hormones regulating appetite control. Several studies have indicated that fructose-containing beverages increase caloric intake at later eating occasions more than sucrose-sweetened beverages. However, many of these studies were done with pure fructose, not HFCS, and results have been very mixed (3). Overall, the body of evidence for this claim is fairly equivocal.
Fructose feeds cancer. A recent study (4) found that pancreatic cancer cells can use fructose to help them grow and proliferate; this paper was picked up by the mainstream media and was billed as one more reason to avoid HFCS. The study builds on previous research, which showed a link between sugar consumption, glycemic load and pancreatic cancer risk (5). While its results are quite interesting, it had significant limitations. For one thing, the researchers fed pure fructose (not HFCS) to cultured cancer cells, conditions which are far removed from the complex environment found in the body. Much more research needs to be done in order to determine if dietary fructose plays a role in the development of pancreatic cancer--and if so, whether there are specific sources of fructose that should be avoided by pancreatic cancer patients.
It's not natural: High fructose corn syrup, in contrast to sugar, maple syrup, and honey, does not occur in nature. It is highly processed in order to yield a sweetener that is tailor-made for the needs of the food industry. Of course, the definition of "natural" may differ from person to person, and the Food and Drug Administration does not regulate this claim, which is why the CRA can legitimately argue that it is a natural sweetener. After all, it is derived from a natural product. However, if (like me) your definition of "natural" includes being as close to its natural state as possible with minimal processing, HFCS definitely does not fit the bill. And if it extends even further, to include a product that is sustainably produced by an environmentally responsible company, HFCS wouldn't even be considered. Because it is processed from corn grown in huge monocrops, it is almost guaranteed to come from genetically engineered corn, and buying it supports huge food industry conglomerates like Archer Daniels Midland and Cargill.
Conclusion
When all is said and done, there are good reasons to avoid HFCS. It is, if nothing else, a handy marker for a food that is highly processed. Once you start reading ingredient labels, you will find that many HFCS-containing products have dozens of ingredients, some of which are better avoided. There isn't really any place for HFCS in a whole foods, plant-based diet.
The bottom line is that you should avoid added sugars as much as possible for optimal health. While bans on HFCS are a step in the right direction, it isn't until we reduce the overall level of added sweeteners in our food supply (and in our own pantries) that we will truly see a difference in the health of our nation.
References
1. Basciano H, Federico L, and Adeli K. Fructose, insulin resistance and metabolic dyslipidemia. Nutrition and Metabolism 2005, 2 (5).
2. Bray GA, Nielsen SJ, and Popkin BM. Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity. American Journal of Clinical Nutrition 2004, 79 (4): 537-543.
3. Moran TH. Fructose and satiety. Journal of Nutrition 2009, 139 (6): 1253S-1256S.
4. Liu H, Huang D, McArthur DL, Boros LG, Nissen N and Heaney AP. Fructose induces transketolase flux to promote pancreatic cancer growth. Cancer Research 2010, 70 (15):6368-76.
5. Michaud DS, Liu S, Giovannucci E, Willett WC, Colditz GA, and Fuchs CS. Dietary sugar, glycemic load, and pancreatic cancer risk in a prospective study. Journal of the National Cancer Institute 2002, 94 (17): 1293-1300.
Corn syrup is made by breaking up corn starch into its component sugars (mostly glucose), which yields the standard corn syrup available in any grocery store. High fructose corn syrup is made when corn syrup undergoes an additional enzymatic reaction to convert its glucose into fructose, which is sweeter than sugar. This is then mixed with pure glucose in varying ratios for different food industry products; the most common form is HFCS-55, which is about 55% fructose and 45% glucose. On the other hand, sugar (sucrose) is made of 50% glucose and 50% fructose (see previous post for sugar chemistry overview). Therefore, the ratios of glucose and fructose are not all that different in the two sweeteners; the term "high fructose" is a bit of a misnomer, and is certainly not interchangeable with pure fructose.
With all that in mind, let's take a look at some of the claims against HFCS and the evidence behind them.
High fructose corn syrup is responsible for the obesity epidemic. This claim originated from the fact that the use of HFCS as a sweetener rose along with the increase in obesity over the last 20 years. However, correlation does not prove causation, and obesity is a complex condition that arises from many factors. Blaming it on a single ingredient oversimplifies the issue. Rather, the obesity epidemic seems to have stemmed from a "toxic food environment," of which HFCS-containing soft drinks are certainly a part, but the incessant food advertising, the ubiquity of fast food restaurants, the subsidization of corn and soybeans (processed to produced HFCS and soybean oil, respectively), and the high cost of healthy foods like fruits and vegetables also contribute to this. Add to this the decrease in physical activity as people become more sedentary, and you have a perfect storm. In so far as HFCS-containing beverages and foods are a contributor to this, they could be considered one of the causes of obesity, but not the only cause.
That being said, there are several underlying biochemical reasons that would support the link between HFCS and obesity. Most importantly, fructose undergoes a different biochemical pathway than glucose; it must be processed in the liver. Unlike glucose, which can feed the body's cells directly, fructose either goes into storage in the liver, or can be converted into fat (triglycerides) for storage or for transport to other cells in the body to use as energy. Since it goes through different pathways, fructose is not regulated by insulin and does not have a direct effect on blood sugar. This may come at the price of elevating triglycerides, however. There is evidence that high intakes of fructose over the long term can lead to insulin resistance and have negative effects on blood lipids (1). Again, this link has been found with pure fructose, so the industry argues that because HFCS is only 5% higher in fructose compared to sugar, these detrimental effects of fructose do not apply to their product.
However, it stands to reason that if intakes are significant enough (and unfortunately, intakes of added sweeteners are extremely high in the U.S), this difference could become important. In fact, total fructose intake increased nearly 30% between 1970 and 2000 (2)--an increase that could have only come from the concomitant increase in the use of HFCS in processed foods. (Most Americans don't come close to meeting the recommended dietary intake of fruit, which is naturally high in fructose, and while honey and agave nectar are also high in fructose, these sweeteners are nowhere near as common as HFCS.) Thus, concerns for HFCS having a detrimental effect on blood lipids seem to be legitimate.
It has also been suggested that HFCS increases appetite, since fructose has different effects from sugar on the hormones regulating appetite control. Several studies have indicated that fructose-containing beverages increase caloric intake at later eating occasions more than sucrose-sweetened beverages. However, many of these studies were done with pure fructose, not HFCS, and results have been very mixed (3). Overall, the body of evidence for this claim is fairly equivocal.
Fructose feeds cancer. A recent study (4) found that pancreatic cancer cells can use fructose to help them grow and proliferate; this paper was picked up by the mainstream media and was billed as one more reason to avoid HFCS. The study builds on previous research, which showed a link between sugar consumption, glycemic load and pancreatic cancer risk (5). While its results are quite interesting, it had significant limitations. For one thing, the researchers fed pure fructose (not HFCS) to cultured cancer cells, conditions which are far removed from the complex environment found in the body. Much more research needs to be done in order to determine if dietary fructose plays a role in the development of pancreatic cancer--and if so, whether there are specific sources of fructose that should be avoided by pancreatic cancer patients.
It's not natural: High fructose corn syrup, in contrast to sugar, maple syrup, and honey, does not occur in nature. It is highly processed in order to yield a sweetener that is tailor-made for the needs of the food industry. Of course, the definition of "natural" may differ from person to person, and the Food and Drug Administration does not regulate this claim, which is why the CRA can legitimately argue that it is a natural sweetener. After all, it is derived from a natural product. However, if (like me) your definition of "natural" includes being as close to its natural state as possible with minimal processing, HFCS definitely does not fit the bill. And if it extends even further, to include a product that is sustainably produced by an environmentally responsible company, HFCS wouldn't even be considered. Because it is processed from corn grown in huge monocrops, it is almost guaranteed to come from genetically engineered corn, and buying it supports huge food industry conglomerates like Archer Daniels Midland and Cargill.
Conclusion
When all is said and done, there are good reasons to avoid HFCS. It is, if nothing else, a handy marker for a food that is highly processed. Once you start reading ingredient labels, you will find that many HFCS-containing products have dozens of ingredients, some of which are better avoided. There isn't really any place for HFCS in a whole foods, plant-based diet.
The bottom line is that you should avoid added sugars as much as possible for optimal health. While bans on HFCS are a step in the right direction, it isn't until we reduce the overall level of added sweeteners in our food supply (and in our own pantries) that we will truly see a difference in the health of our nation.
References
1. Basciano H, Federico L, and Adeli K. Fructose, insulin resistance and metabolic dyslipidemia. Nutrition and Metabolism 2005, 2 (5).
2. Bray GA, Nielsen SJ, and Popkin BM. Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity. American Journal of Clinical Nutrition 2004, 79 (4): 537-543.
3. Moran TH. Fructose and satiety. Journal of Nutrition 2009, 139 (6): 1253S-1256S.
4. Liu H, Huang D, McArthur DL, Boros LG, Nissen N and Heaney AP. Fructose induces transketolase flux to promote pancreatic cancer growth. Cancer Research 2010, 70 (15):6368-76.
5. Michaud DS, Liu S, Giovannucci E, Willett WC, Colditz GA, and Fuchs CS. Dietary sugar, glycemic load, and pancreatic cancer risk in a prospective study. Journal of the National Cancer Institute 2002, 94 (17): 1293-1300.
Sunday, August 1, 2010
The Glycemic Index
It's no secret that humans have an innate sweet tooth. We have evolved through time to crave the concentrated energy that sweet foods provide. Unlike most of human history, however, where most sugar came in the forms of fruit and honey, our current environment offers an ever-expanding supply of foods with added sugars. This includes not only sweet treats and desserts, but many other products on grocery store shelves, from cereals to crackers to peanut butter. As such, sugar has become an increasing target of public health concern, with some groups going so far as to contest that the obesity epidemic was caused by high fructose corn syrup (HFCS), and others saying that refined sugar should be avoided altogether.
In order to help make sense of the conflicting information out there and give you a nutrition professional's perspective on the topic, I am starting a new blog series on sweeteners. First up: a short summary of sugar chemistry, and a discussion of the glycemic index. Posts on HFCS and agave nectar will follow.
Sugar Chemistry 101
The sugars that we consume in food consist of two sugar molecules linked together. Table sugar, sucrose, is made up of a glucose molecule and a fructose molecule. These molecules are broken apart during digestion and have different pathways into the bloodstream, where they can be used to provide energy for cells throughout the body.
Glucose can be absorbed directly into the bloodstream, and its availability to cells is extensively regulated by hormones including insulin. If there is an excess of glucose in the blood, it can be carried to the liver, muscle, and fat cells for storage. In most individuals, the action of insulin prevents glucose from building up into high levels, but diabetics and those with insulin resistance cannot adequately regulate glucose levels, leading to a high concentration of blood glucose.
Many of us occasionally experience a sugar crash following a sugary meal or snack, even if we don't have diabetes. This occurs because the large intake of sugar requires a large secretion of insulin to remove it from the blood, which can lead to low sugar levels and a feeling of sluggishness.
The Glycemic Index
Some carbohydrate-containing foods influence blood glucose more than others. The glycemic index (GI) of a food is a measure of a specific food's influence on blood sugar levels. While GI can be a useful tool, it does have some drawbacks. For example, the GI for specific foods can vary greatly depending on the testing conditions, as well as the preparation of the food. Take pasta, which actually has a fairly low GI if it is cooked al dente. If it is overcooked, the GI increases dramatically. Also, the glycemic response to a meal is different than the glycemic response to one food; a meal containing sources of protein and fat will have less of an effect on blood sugar than the carbohydrate-containing food eaten on its own.
Paying attention to the glycemic index of foods can be helpful for individuals with diabetes. However, keep in mind that GI figures are an average of the blood sugar responses of a few research participants (usually about 10 people for each food), and that it is far more important to consider your own response. You don't have to rule out all foods that are high GI; instead, try testing your blood sugar before and after eating a food to see how it affects you. This is true for everyone--it is always important to listen to your body and do the things that make you feel your best.
In conclusion, the GI can be a useful guide for helping to plan a healthful diet, but you don't have to look up GI values for every food you eat. Luckily, the dietary advice boils down to the same general healthy eating guidelines as usual: base your diet on whole grains, fruits and vegetables, and limit high-sugar foods such as sweetened beverages and desserts. Make sure your meals contain a whole grain or high-fiber carbohydrate source, along with sources of protein and fat, to satisfy your appetite and avoid sugar crashes. Think: oatmeal with nuts and fruit for breakfast, whole wheat pita with hummus and a salad with vinaigrette dressing for lunch, and Chinese-style brown rice noodles with stir-fried tofu and broccoli for dinner. This will help your blood sugar stay within the normal range and leave you feeling healthy and energetic.
If you are interested in learning more about the glycemic index, a great resource is the University of Sydney's website.
In order to help make sense of the conflicting information out there and give you a nutrition professional's perspective on the topic, I am starting a new blog series on sweeteners. First up: a short summary of sugar chemistry, and a discussion of the glycemic index. Posts on HFCS and agave nectar will follow.
Sugar Chemistry 101
The sugars that we consume in food consist of two sugar molecules linked together. Table sugar, sucrose, is made up of a glucose molecule and a fructose molecule. These molecules are broken apart during digestion and have different pathways into the bloodstream, where they can be used to provide energy for cells throughout the body.
Glucose can be absorbed directly into the bloodstream, and its availability to cells is extensively regulated by hormones including insulin. If there is an excess of glucose in the blood, it can be carried to the liver, muscle, and fat cells for storage. In most individuals, the action of insulin prevents glucose from building up into high levels, but diabetics and those with insulin resistance cannot adequately regulate glucose levels, leading to a high concentration of blood glucose.
Many of us occasionally experience a sugar crash following a sugary meal or snack, even if we don't have diabetes. This occurs because the large intake of sugar requires a large secretion of insulin to remove it from the blood, which can lead to low sugar levels and a feeling of sluggishness.
The Glycemic Index
Some carbohydrate-containing foods influence blood glucose more than others. The glycemic index (GI) of a food is a measure of a specific food's influence on blood sugar levels. While GI can be a useful tool, it does have some drawbacks. For example, the GI for specific foods can vary greatly depending on the testing conditions, as well as the preparation of the food. Take pasta, which actually has a fairly low GI if it is cooked al dente. If it is overcooked, the GI increases dramatically. Also, the glycemic response to a meal is different than the glycemic response to one food; a meal containing sources of protein and fat will have less of an effect on blood sugar than the carbohydrate-containing food eaten on its own.
Paying attention to the glycemic index of foods can be helpful for individuals with diabetes. However, keep in mind that GI figures are an average of the blood sugar responses of a few research participants (usually about 10 people for each food), and that it is far more important to consider your own response. You don't have to rule out all foods that are high GI; instead, try testing your blood sugar before and after eating a food to see how it affects you. This is true for everyone--it is always important to listen to your body and do the things that make you feel your best.
In conclusion, the GI can be a useful guide for helping to plan a healthful diet, but you don't have to look up GI values for every food you eat. Luckily, the dietary advice boils down to the same general healthy eating guidelines as usual: base your diet on whole grains, fruits and vegetables, and limit high-sugar foods such as sweetened beverages and desserts. Make sure your meals contain a whole grain or high-fiber carbohydrate source, along with sources of protein and fat, to satisfy your appetite and avoid sugar crashes. Think: oatmeal with nuts and fruit for breakfast, whole wheat pita with hummus and a salad with vinaigrette dressing for lunch, and Chinese-style brown rice noodles with stir-fried tofu and broccoli for dinner. This will help your blood sugar stay within the normal range and leave you feeling healthy and energetic.
If you are interested in learning more about the glycemic index, a great resource is the University of Sydney's website.
Thursday, June 24, 2010
First CSA Box of the Season
Summer is officially here, and so is the beginning of our CSA season with Helsing Junction Farm. We are looking forward to another wonderful summer of produce, and are thrilled that this year they have added a fruit share as well! We picked up our first box today and have already made quite a dent in it (especially the strawberries, which are melt-in-your-mouth delicious).
Today we received:
2 bunches arugula
1 bunch rapini
1 bunch bok choy
2 bunches lettuce
1 bunch chives
1 head green garlic
1 pint strawberries
Brett whipped up a wonderful summer pasta dish with sauteed arugula and garlic, white beans, heirloom tomatoes from yesterday's farmers market, chives, balsamic vinegar and olive oil. What a perfect way to usher in the season!
Today we received:
2 bunches arugula
1 bunch rapini
1 bunch bok choy
2 bunches lettuce
1 bunch chives
1 head green garlic
1 pint strawberries
Brett whipped up a wonderful summer pasta dish with sauteed arugula and garlic, white beans, heirloom tomatoes from yesterday's farmers market, chives, balsamic vinegar and olive oil. What a perfect way to usher in the season!
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