Besides Nutrition is Toxicology (dosage/concentration), my other
mantra is becoming "No Nutrient Works in Isolation". Metabolism is an
amazingly interactive system - one dietary change isn't going to have
one effect. Anytime anyone says one aspect of nutrition is bad for you,
you must think "in what context?" This is similar to thinking about
evolution and natural selection - saying one variant is bad for you is
misleading - in what environment does that gene have a detrimental
outcome?
Obviously, there are genetic defects that are not viable - but for gene variants that we associate with long-term health, good/bad are based on context. As I mentioned before in the folic acid post, the most widespread TT variant of MTHFR seems to be detrimental for maintaining methylation - but probably only in an environment where folic acid and riboflavin intake is low.
A quick google search on Fructose and Health effects will take you to websites explaining that dietary fructose is a poison, exacerbates/induces Metabolic Syndrome, leads to fat accumulation, leptin resistance and a number of other conditions that rouse up a lot of fear - Many of these websites are alternative health providers, 'natural' news sites, low carb diet sites, and ancestral diet enthusiasts.
Fructose has moved into the realm of gluten where I can't even talk to alternative health followers about it because their science is so clouded with sentiment. One of the first people to really make an issue out of this, to my knowledge, was Dr. Lustig. First, if you're interested, and I HIGHLY recommend it, is a link to a talk at the Experimental Biology meeting - they had a symposium specifically on sugar, the effects of fructose and HFCS: http://www.visiond.com/ASN_2012/Sun_Sym_Fructose/QandA.html
If you don't have time to watch the video, they basically bash a lot of fructose research because it looks at the effect of high fructose feedings- fructose in our food supply is almost always bound in a sugar complex. There are also suggestions that the rat model is not the best to study behavioural outcomes of sugar consumption, such as leptin resistance and satiety. Critiques also suggest rat vs human liver experience different gene expression patterns as a result of fructose intake. Rats contain an enzyme called uricase - primates lost this gene, it's interestingly caused controversy with the out of Africa hypothesis - but the presence of this gene in rats requires higher levels of fructose to induce metabolic syndrome. De novo lipogenesis in humans from carbohydrates is drastically different from rats (3-15% vs 60-90%) - so all of those websites that tell you that fructose is shuttling carbohydrate calories into your adipocytes are relying on data from an inadequate model. If the rat isn't an appropriate model, then controlled human studies must be looked to - as mentioned in the critique, the outcomes are much less dim or require a huge quantity of fructose. This example (1) required 100g of fructose per day - not outside of the realm of possibility for someone who drinks a 2liter of coke a day, but not of concern for someone eating 5 servings of fruit.
The most important comment, to me, is that the behaviour (effects on lipids, glycemia, uric acid, nonalcoholic fatty liver disease) of fructose is the same as starch, glucose, and sucrose, when diets were isocaloric. However, for hypercaloric conditions, the negative effects of fructose on lipids, fatty acid deposition, NAFLD, etc are seen. It appears to be fructose consumed in excess of caloric needs that is contributing to the pathophysiology of metabolic syndrome and insulin resistance - the speaker notes that his research is not published, but there is plenty of other research that supports a similar stance - here's a meta-analysis (2) that concludes excess CALORIES from fructose may lead to excess body weight. I don't doubt this much but for healthy/active individuals who are already consuming a caloric load in the range of their needs, there is no need for hysteria or worry over fructose.
I've talked about it before - nutrients don't work in isolation. Fructose is almost never consumed alone in our food system - unless you're guzzling spoonfuls of agave nectar. A lot of Dr. Lustig's studies look at isolated fructose's effect on gene expression and physiology. There's a huge difference between this and say, the fructose bound to glucose in the sugar baked into loaf of bread.
I'm in no way advocating for higher sugar consumption - what prompted this post was an email from my favorite alternative medicine practitioner - Dr. Mercola. I signed up to get his email daily because I like to guess what his provocative headline will discuss that day - his articles usually start in a place of science and then take a sharp left turn. Look at this article: http://articles.mercola.com/sites/articles/archive/2011/10/14/why-this-sugar-make-you-and-most-others-fat.aspx
Advocating only consuming 15g of fructose a day from fruit? One cup of apples, 65 calories, has 7.3g of fructose. You can debate the semantics of what the most ideal level of fruit consumption is, but there is no good public health reasoning to say that eating more than 2 apples a day is bad for your health. This borders on absurdity. (note: I googled the fructose in an apple and the top hit was a Paleo based website) Even Dr. Lustig himself has said that fruit, because it comes with fiber, is not as concerning. This sort of research is getting perverted by alternative healthcare practitioners.
No nutrient works in isolation (sick of that yet?). Grape polyphenols have been shown to attenuate the negative effects of added, isolated fructose to the diets of non-diabetic overweight/obese individuals related to type 2 diabetics (3). Another great nutrition blog that I'd recommend following (4) evaluated a study on the effects of strawberry polyphenols and fiber on metabolic dysfunction.
Overall, what's the point of focusing on fructose? Is the point to reduce fructose in the food supply so we can have overweight/obese individuals with lower rates of metabolic syndrome? This research is interesting in and of itself but nutritional sciences has long harped on reducing calories for ideal weight/health - this research doesn't change that.
Be careful of what you read on the internet. Be Skeptical of anything that attempts to arouse a sentimental response in you. If someone poses something as absolute fact, be even more skeptical. Cutting down on your added sugar intake can have numerous benefits, but skimping on fruit to reduce your fructose intake is not supported by science.
1. http://www.ncbi.nlm.nih.gov/pubmed/23825185
2. http://www.ncbi.nlm.nih.gov/pubmed/22351714
3. http://www.ncbi.nlm.nih.gov/pubmed/23275372
4. http://nutsci.org/2012/01/06/strawberry-polyphenols-mitigate-very-high-dietary-fructose-induced-metabolic-dysfunction-in-rats/
Obviously, there are genetic defects that are not viable - but for gene variants that we associate with long-term health, good/bad are based on context. As I mentioned before in the folic acid post, the most widespread TT variant of MTHFR seems to be detrimental for maintaining methylation - but probably only in an environment where folic acid and riboflavin intake is low.
A quick google search on Fructose and Health effects will take you to websites explaining that dietary fructose is a poison, exacerbates/induces Metabolic Syndrome, leads to fat accumulation, leptin resistance and a number of other conditions that rouse up a lot of fear - Many of these websites are alternative health providers, 'natural' news sites, low carb diet sites, and ancestral diet enthusiasts.
Fructose has moved into the realm of gluten where I can't even talk to alternative health followers about it because their science is so clouded with sentiment. One of the first people to really make an issue out of this, to my knowledge, was Dr. Lustig. First, if you're interested, and I HIGHLY recommend it, is a link to a talk at the Experimental Biology meeting - they had a symposium specifically on sugar, the effects of fructose and HFCS: http://www.visiond.com/ASN_2012/Sun_Sym_Fructose/QandA.html
If you don't have time to watch the video, they basically bash a lot of fructose research because it looks at the effect of high fructose feedings- fructose in our food supply is almost always bound in a sugar complex. There are also suggestions that the rat model is not the best to study behavioural outcomes of sugar consumption, such as leptin resistance and satiety. Critiques also suggest rat vs human liver experience different gene expression patterns as a result of fructose intake. Rats contain an enzyme called uricase - primates lost this gene, it's interestingly caused controversy with the out of Africa hypothesis - but the presence of this gene in rats requires higher levels of fructose to induce metabolic syndrome. De novo lipogenesis in humans from carbohydrates is drastically different from rats (3-15% vs 60-90%) - so all of those websites that tell you that fructose is shuttling carbohydrate calories into your adipocytes are relying on data from an inadequate model. If the rat isn't an appropriate model, then controlled human studies must be looked to - as mentioned in the critique, the outcomes are much less dim or require a huge quantity of fructose. This example (1) required 100g of fructose per day - not outside of the realm of possibility for someone who drinks a 2liter of coke a day, but not of concern for someone eating 5 servings of fruit.
The most important comment, to me, is that the behaviour (effects on lipids, glycemia, uric acid, nonalcoholic fatty liver disease) of fructose is the same as starch, glucose, and sucrose, when diets were isocaloric. However, for hypercaloric conditions, the negative effects of fructose on lipids, fatty acid deposition, NAFLD, etc are seen. It appears to be fructose consumed in excess of caloric needs that is contributing to the pathophysiology of metabolic syndrome and insulin resistance - the speaker notes that his research is not published, but there is plenty of other research that supports a similar stance - here's a meta-analysis (2) that concludes excess CALORIES from fructose may lead to excess body weight. I don't doubt this much but for healthy/active individuals who are already consuming a caloric load in the range of their needs, there is no need for hysteria or worry over fructose.
I've talked about it before - nutrients don't work in isolation. Fructose is almost never consumed alone in our food system - unless you're guzzling spoonfuls of agave nectar. A lot of Dr. Lustig's studies look at isolated fructose's effect on gene expression and physiology. There's a huge difference between this and say, the fructose bound to glucose in the sugar baked into loaf of bread.
I'm in no way advocating for higher sugar consumption - what prompted this post was an email from my favorite alternative medicine practitioner - Dr. Mercola. I signed up to get his email daily because I like to guess what his provocative headline will discuss that day - his articles usually start in a place of science and then take a sharp left turn. Look at this article: http://articles.mercola.com/sites/articles/archive/2011/10/14/why-this-sugar-make-you-and-most-others-fat.aspx
Advocating only consuming 15g of fructose a day from fruit? One cup of apples, 65 calories, has 7.3g of fructose. You can debate the semantics of what the most ideal level of fruit consumption is, but there is no good public health reasoning to say that eating more than 2 apples a day is bad for your health. This borders on absurdity. (note: I googled the fructose in an apple and the top hit was a Paleo based website) Even Dr. Lustig himself has said that fruit, because it comes with fiber, is not as concerning. This sort of research is getting perverted by alternative healthcare practitioners.
No nutrient works in isolation (sick of that yet?). Grape polyphenols have been shown to attenuate the negative effects of added, isolated fructose to the diets of non-diabetic overweight/obese individuals related to type 2 diabetics (3). Another great nutrition blog that I'd recommend following (4) evaluated a study on the effects of strawberry polyphenols and fiber on metabolic dysfunction.
Overall, what's the point of focusing on fructose? Is the point to reduce fructose in the food supply so we can have overweight/obese individuals with lower rates of metabolic syndrome? This research is interesting in and of itself but nutritional sciences has long harped on reducing calories for ideal weight/health - this research doesn't change that.
Be careful of what you read on the internet. Be Skeptical of anything that attempts to arouse a sentimental response in you. If someone poses something as absolute fact, be even more skeptical. Cutting down on your added sugar intake can have numerous benefits, but skimping on fruit to reduce your fructose intake is not supported by science.
1. http://www.ncbi.nlm.nih.gov/pubmed/23825185
2. http://www.ncbi.nlm.nih.gov/pubmed/22351714
3. http://www.ncbi.nlm.nih.gov/pubmed/23275372
4. http://nutsci.org/2012/01/06/strawberry-polyphenols-mitigate-very-high-dietary-fructose-induced-metabolic-dysfunction-in-rats/
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