Early in his career as a patent examiner Albert Einstein had a boss whose credo was "You have to remain critically vigilant". He urged the young Albert to question every premise, challenge conventional wisdom and never accept the truth of something merely because everyone else views it as obvious; resist being credulous. Einstein developed an independence of judgment that allowed him to challenge basic assumptions.
What has me thinking about Einstein is not his theory of relativity, but rather a book I've just read by Carol Tavris and Elliot Aronson called "Mistakes Were Made (but not by me): Why We Justify Foolish Beliefs, Bad Decisions, and Hurtful Acts". Tavris and Aronson propose that a lot of what ails us as a society is based on our inability to admit that we've been wrong. And what I'm leading up to here is that perhaps it's time we admitted that our promotion of high omega-6 vegetable oils might have been a bit over the top. In our valid haste to get trans fats out of the diet, I fear that not enough attention was paid to the possible downside of just what would replace hydrogenated vegetable oils in the myriad of products that used them. The general thinking was that replacing trans fats with saturated fats would merely be a leap out of the fat and into the fire since "everybody knows" that saturated fats lead to heart disease. (I'll present evidence against that notion in another piece). We now know that perception becomes reality irrespective of fact when enough people believe it; or in other words, if we feel it's true, then it is --even if it isn't! Those of you old enough might recall when our advice to all (cardiac patient or not) was to severely limit the intake of the demon egg. Sure enough, we have egg on our collective faces over that one...though nobody seems particularly embarrassed by how wrong we were (nutrition is an evolving science, after all).
So my issue now is not to suggest that animal fats should at least partially replace hydrogenated fats (although I think they should), but instead to dray attention to the real threat posed by excessive intake of the omega-6 fatty acids, especially when that intake further skews an already inappropriate ratio of omega-6:omega-3. The importance of omega-3s in the diet won't be discussed today, since I'm pretty sure that most people are aware of this fact already.
Statistics reveal that the diet of the average person in developed countries contain roughly ten times more vegetable oil than it did fifty years ago. I would go so far as to suggest that we're consuming roughly 1000 times more than we did a century ago. After all, who could squeeze a corn cob? Expressed oil simply wasn't available, although those who lived around the Mediterranean did have olive oil with its relatively low level of linoleic acid. Over fifty years ago it was determined that the necessary requirement for essential fatty acids is fulfilled when 1 to 2 percent of the total daily caloric intake is provided by linoleic acid...a diet of 1800 calories per day should provide 2 to 4 grams of linoleic acid (an omega-6 fatty acid). Current intake of linoleic acid, by many estimates, is in the 19-22 percent range...and going higher. There has been speculation that the effectiveness of statin treatment is due to not only lowering serum fatty acid concentrations, but also to altering the relative percentages of omega-6 and omega-3 fatty acids. It is evident from the research literature that lipid oxidation in vivo can and does occur (with linoleic acid being one of the prime substrates), and that this is detrimental to human health.
Omega-6 and Cancer
Linoleic acid is the only fatty acid to exhibit an unequivocal cancer-enhancing effect in rodents, impacting mammary, pancreatic and colon cancer. A number of nutrients exhibit tumour-enhancing properties, but excessive levels of intake are usually required. This is not the case, however, with linoleic acid of which only five times the amount needed for optimal growth will bring about mammary tumour development in rats. The effect of "fat type: has been the subject of a great deal of research, but the effects are almost always related to linoleic acid intake. The more linoleic acid in a product (corn oil, for example), the more carcinogenesis enhancement compared to low linoleic acid foods like fish oils, dairy fat and beef tallow.
In 1997 D.P. Rose examined the effect of dietary fatty acids on breast and prostate cancer and concluded that "omega-6 fatty acids perform functions in experimental prostate cancer progression similar to those described for breast cancer" and that saturated fats have no effect on breast carcinogenesis or progression. S. L. Goodstine's research indicated that a higher omega-3:omega-6 ratio would reduce the risk of breast cancer, especially in pre-menopausal women. Hilakivi-Clarke looked at the influence of maternal diet on breast cancer risk among female offspring and determined that "a high dietary linoleic acid intake can elevate pregnancy estrogen levels and this, possibly by altering mammary gland morphology and expression of fat-and/or estrogen-regulated genes, can increase breast cancer risk in the offspring. If true for women, breast cancer prevention in daughters may include modulating the mother's pregnancy intake of some dietary fats". It's not a great stretch to postulate that the same may be true regarding prostate cancer risk in male offspring of mothers on diets rich in linoleic acid. In fact, writing a commentary in Carcinogenesis, Bartsch was of the opinion that a high intake of PUFAs stimulates several stages in the development of mammary, colon and possibly prostate cancer from an increase in oxidative DNA damage to effects on cell proliferation, free estrogen levels to hormonal catabolism. Results from the EURAMIC (European Community Multicentre Study on Antioxidants, Myocardial Infarction, and Cancer) breast cancer study also provide evidence for the hypothesis that the balance between omega-6 and omega-3 may play a role in breast cancer. Spanish researchers found that an excess of omega-6 fats in the diet accelerates breast cancer by altering the activity of a group of genes.
Looking specifically at prostate cancer Godley researched biomarkers of essential fatty acid consumption and found that "linoleic acid consumption was positively associated with prostate cancer risk, which is consistent with results from animal experiments". Wang investigated the impact of high versus low-fat diet on risk of prostate cancer and found that fat reduction was definitely helpful The reporting of that study, however, generally failed to mention that the source of the fat in the high-fat diet was linoleic acid (0mega-6) rich corn oil. A 2006 study found that a diet rich in omega-6 fatty acids appeared to promote the spread of prostate cancer, while a diet rich in omega-3s impeded the spread. Hughes-Fulford in 2006 found a significant link between the ratio of omega-6:0mega-3 and prostate cancer and was quoted as saying she would never use any of the high-linoleic acid oils. In 2007 Neuhauser and his group found that omega-6 rich oils increase, and dairy foods decrease prostate cancer risk.
Among several conditions laid at the foot of excessive linoleic acid intake are asthma. eczema, allergic rhinitis, and hay fever. Additionally, PUFAs have been associated with weight gain in adults and children. Writing in Obesity Reviews, Ailhud summarized "experimental evidence which supports polyunsaturated fatty acids of the omega-6 series as being potent promoters of both adipogenesis in vitro and adipose tissue development in vivo during the gestation/lactation period. It is proposed that unnoticed changes in fatty acid composition of ingested fats over the last decades have been important determinants in the increasing prevalence of childhood overweight and obesity" And finally, a case-control study Nkondjock gave evidence that substituting polyunsaturated fatty acids with saturated or monounsaturated fatty acids may reduce pancreatic cancer risk.
Thomas Edison once said "The doctor of the future will give no medicine, but will interest his patients in the care of the human body, in diet and in the cause of prevention of disease". Though Edison was no dietitian, I think he was on to something. I also think we must strive to avoid "group think"...the process whereby like-minded people, talking only with one another, usually end up believing a more extreme version of what they thought before they started to talk. One of the reasons for this, according to American researchers David Meyers and G.D. Bishop, is that when people's views are confirmed by others they tend to become more confident and more extreme. Another reason is that most people are loath to come down on the wrong side of an issue on which there seems to be consensus.
Refernces available on request.
Friday, June 19, 2009
Monday, June 15, 2009
Vitamin D...the sunshine of your life
A few years ago I had a skin cancer diagnosed on my nose. I commented hopefully to the dermatologist that I had the best kind of skin cancer one could have, and with a withering look she replied that there were no good kinds, but at least mine wasn't the worst. True enough. She then went on to recommend that I cover myself completely every day with a # 60 sun screen, even when indoors. When I asked what she told her patients about vitamin D after warning them to completely avoid the sun and wear sun-screen, she replied that she told them nothing. "What's the big deal?" was her attitude.
Well, it's a very big deal. While I'm unaware of any dermatologist ever being held liable for telling a patient to totally avoid the sun and not recommending vitamin D supplements, I bet it won't be long before such a case comes to light. Vitamin D deficiency is widespread, and not just in people who are being treated for skin cancer. It's been estimated that roughly two-thirds of the Canadian population has a vitamin D deficiency. At least in Canada milk is fortified with vitamin D, (not enough, but that's another story). Residents of some other northern geographical countries, however, are not so lucky.
For a long time it was thought that the only real upshot of inadequate vitamin D would be rickets in children...a serious problem. Fortification of milk with the vitamin pretty well put an end to that, but lately, for a variety of reasons, rickets has been reappearing. Northern First Nations children were among the first to be seen in this resurgence of the condition, but now there is also evidence of the vitamin D deficiency disease called osteomalacia in adults as well. Particularly vulnerable are those women who immigrate to Canada from countries where fluid milk is not routinely consumed and whose religion or culture requires them to be covered from head to foot. Osteoporosis is not just the result of inadequate dietary calcium; poor vitamin D status plays a role as well. A favourite aunt of mine was confined to a nursing home thanks to complications from diabetes and the subsequent amputation of one of her legs. Though I kept nagging them to give her vitamin D supplements they neglected to do so. One day I received a call saying that she had rolled over in bed and broken her remaining leg. The next day she was dead from complications of the break.
Unfortunately it's not just the bones that pay a price for insufficient vitamin D. There is now pretty persuasive evidence that an inadequate intake of this vitamin plays a role in the development of hypertension, heart disease, certain cancers, diabetes and autoimmune illnesses.
This naturally enough leads to the question as to why so many people have inadequate vitamin D and what are the natural sources of it. The industrial revolution is partly to blame for this sad state of affairs (all that smoke and smog)...that and the fact that nature didn't think we'd be silly enough to migrate to colder climes (she figured we'd stay in the Garden of Eden wearing only a fig leaf and getting plenty of sunshine). But the move to cities and the development of polluting industries coupled with the need to wear clothes and the invention of sun-screen did us in. Don't get me wrong: I'm not suggesting that we shouldn't use sun-screen, I'm simply pointing out that it pretty much does away with the skin's production of vitamin D. Because of the northern geographical setting of many industrialized countries there is little or no vitamin D produced by the skin between October and April (not to mention the fact that we're all bundled up during those months). And as for food, don't count on it. Milk is fortified with vitamin D, but as of this writing still only gives 100 IUs per 250 mL (eight ounces). Not enough...even if you have four glasses of milk per day (which I think you should). Contrary to popular belief, most other dairy products have none, or very little. Unless you're eating very large quantities of oily fish, your diet is highly unlikely to provide you with all the vitamin D you need.
So the, what to do? You might know that dietitians are usually reluctant to recommend supplements since for most nutrients food is the best source...but for vitamin D we must make an exception. I would suggest that for most people a supplement of 1000 IU of vitamin D3 (cholecalciferol) per day (perhaps even as much as 2000 IUs) per day would be appropriate. You might be tempted to take cod or halibut liver oil but I think that's a bad idea since a tablespoon of the stuff will also give you about 14,000 IU of vitamin A...way too much. I would opt for a pill/capsule that contains only vitamin D.
Can you get too much? Yes. Toxicity can occur since the vitamin is fat-soluble and can be stored over time. Most evidence indicates that you'd need 20,000 IU a day over a long period of time to have problems, but to err on the side of caution I think you should not exceed the 2000 IU level. Are there people who shouldn't take supplements of vitamin D? Yes, those with a condition called sarcoidosis (or any other granulomatous disease), lymphoma, or hyperparathyroidism.
The bottom line here is that most of us are not getting enough vitamin D and the result can be serious.
Well, it's a very big deal. While I'm unaware of any dermatologist ever being held liable for telling a patient to totally avoid the sun and not recommending vitamin D supplements, I bet it won't be long before such a case comes to light. Vitamin D deficiency is widespread, and not just in people who are being treated for skin cancer. It's been estimated that roughly two-thirds of the Canadian population has a vitamin D deficiency. At least in Canada milk is fortified with vitamin D, (not enough, but that's another story). Residents of some other northern geographical countries, however, are not so lucky.
For a long time it was thought that the only real upshot of inadequate vitamin D would be rickets in children...a serious problem. Fortification of milk with the vitamin pretty well put an end to that, but lately, for a variety of reasons, rickets has been reappearing. Northern First Nations children were among the first to be seen in this resurgence of the condition, but now there is also evidence of the vitamin D deficiency disease called osteomalacia in adults as well. Particularly vulnerable are those women who immigrate to Canada from countries where fluid milk is not routinely consumed and whose religion or culture requires them to be covered from head to foot. Osteoporosis is not just the result of inadequate dietary calcium; poor vitamin D status plays a role as well. A favourite aunt of mine was confined to a nursing home thanks to complications from diabetes and the subsequent amputation of one of her legs. Though I kept nagging them to give her vitamin D supplements they neglected to do so. One day I received a call saying that she had rolled over in bed and broken her remaining leg. The next day she was dead from complications of the break.
Unfortunately it's not just the bones that pay a price for insufficient vitamin D. There is now pretty persuasive evidence that an inadequate intake of this vitamin plays a role in the development of hypertension, heart disease, certain cancers, diabetes and autoimmune illnesses.
This naturally enough leads to the question as to why so many people have inadequate vitamin D and what are the natural sources of it. The industrial revolution is partly to blame for this sad state of affairs (all that smoke and smog)...that and the fact that nature didn't think we'd be silly enough to migrate to colder climes (she figured we'd stay in the Garden of Eden wearing only a fig leaf and getting plenty of sunshine). But the move to cities and the development of polluting industries coupled with the need to wear clothes and the invention of sun-screen did us in. Don't get me wrong: I'm not suggesting that we shouldn't use sun-screen, I'm simply pointing out that it pretty much does away with the skin's production of vitamin D. Because of the northern geographical setting of many industrialized countries there is little or no vitamin D produced by the skin between October and April (not to mention the fact that we're all bundled up during those months). And as for food, don't count on it. Milk is fortified with vitamin D, but as of this writing still only gives 100 IUs per 250 mL (eight ounces). Not enough...even if you have four glasses of milk per day (which I think you should). Contrary to popular belief, most other dairy products have none, or very little. Unless you're eating very large quantities of oily fish, your diet is highly unlikely to provide you with all the vitamin D you need.
So the, what to do? You might know that dietitians are usually reluctant to recommend supplements since for most nutrients food is the best source...but for vitamin D we must make an exception. I would suggest that for most people a supplement of 1000 IU of vitamin D3 (cholecalciferol) per day (perhaps even as much as 2000 IUs) per day would be appropriate. You might be tempted to take cod or halibut liver oil but I think that's a bad idea since a tablespoon of the stuff will also give you about 14,000 IU of vitamin A...way too much. I would opt for a pill/capsule that contains only vitamin D.
Can you get too much? Yes. Toxicity can occur since the vitamin is fat-soluble and can be stored over time. Most evidence indicates that you'd need 20,000 IU a day over a long period of time to have problems, but to err on the side of caution I think you should not exceed the 2000 IU level. Are there people who shouldn't take supplements of vitamin D? Yes, those with a condition called sarcoidosis (or any other granulomatous disease), lymphoma, or hyperparathyroidism.
The bottom line here is that most of us are not getting enough vitamin D and the result can be serious.
Friday, June 12, 2009
Chicken Soup for the Time-Deprived
When I was a kid my Dad's method of conveying contempt for the lack of flavour in canned chicken soup was to exclaim that it tasted as though a chicken might have walked through it. This discussion took place very infrequently--on the rare occasion that my mother would venture into the world of ready-made, canned foods. She, of course, was the World War 2 type of homemaker that made everything--and I mean everything--from scratch. If chicken soup were on the menu, then she started with a chicken. I can also remember my grandmother making chicken soup, and she started with a live chicken.
What brought all this to mind was my daughter-in-law asking what I thought of the chicken-soup powders and instant chicken bouillon mixes. I had to admit I hadn't thought about them much and, in fact, wasn't even sure what was in them. She said she thought they were very convenient, especially as a base for other soups and casseroles but was a bit worried about what they contained. And believe me, as I soon discovered, she had good reason to be concerned. The ingredient list (and I compared a number of brands and they're all pretty much the same) is as follows:
Corn syrup solids, dextrose, flour, sugar, cornstarch, chicken fat, hydrolysed soy and corn protein. Those are the first seven ingredients. As you know, ingredients are listed by order of weight, so the amount of dehydrated chicken, coming as it does at number nine, following "flavours", and just before guar gum, doesn't auger well for the chicken's relationship to the soup. I don't think a chicken even walked through it!
What I find alarming about the ingredient list, aside from the dearth of chicken, is that corn syrup solids heads the list. There is a great deal of research (some of it showing conflicting results) that these syrups, particularly high-fructose corn syrups, which most of them are, are associated with the increased incidence of obesity. Another concern around these types of mixes is the sodium content, and my comparative shopping yielded another puzzlement: While the powders came in at around 100 mg of sodium per 250 mL of prepared soup, one of the samples I examined (boasting 25% less salt), actually contained 527 mg of sodium. Go figure.
All of this raises the question "At what cost convenience?" While it's certainly true that adding some boiling water to a powder takes significantly less time than boiling a chicken, there are many so-called "convenience" foods that don't even save much time. There must be a point at which even the most time-deprived cook will admit it's not worth the health, and nutrition costs, never mind the money, to save a few minutes. As for the chicken broth, there are canned and packaged versions that are more expensive, but at least had a nodding acquaintance with a hen.
It's not that I underestimate the value of convenience. These days with both partner frequently working outside the home, time is money. But I think we need to do a careful assessment of the situation. I'm reminded that at the end of both World Wars people didn't have the option, or the cash, to send out for a pizza or stop off on the way home from work to pick up a fully-cooked meal. But when you think about it, you could easily broil some pork chops and nuke some potatoes and frozen veggies in half the time and at half the cost it takes to have the pizza delivered or stop off at the supermarket for a ready-made meat loaf. Just for the fun of it, time yourself and see how long it takes to whip up some pasta with tomato sauce and grated cheese.
Being a nutritionist I tend to put more importance on the control you have over home-made foods rather than time spent on preparation. When you make it yourself you can be sure that there's no shortening with all the trans fatty acids, no excess salt, no monosodium glutamate, no excess fat and sugar. What a deal! I don't mean to come across as the grumpy old lady I may seem--but honestly, if you're going to shell out big bucks for food, you should be saving a lot of time and nutrients. I remember when I was a young, working mother I'd feel guilty if I occasionally resorted to packaged macaroni and cheese. Today that package seems like it entails a lot of work compared to the ready-made frozen product that is popped into the microwave.
What brought all this to mind was my daughter-in-law asking what I thought of the chicken-soup powders and instant chicken bouillon mixes. I had to admit I hadn't thought about them much and, in fact, wasn't even sure what was in them. She said she thought they were very convenient, especially as a base for other soups and casseroles but was a bit worried about what they contained. And believe me, as I soon discovered, she had good reason to be concerned. The ingredient list (and I compared a number of brands and they're all pretty much the same) is as follows:
Corn syrup solids, dextrose, flour, sugar, cornstarch, chicken fat, hydrolysed soy and corn protein. Those are the first seven ingredients. As you know, ingredients are listed by order of weight, so the amount of dehydrated chicken, coming as it does at number nine, following "flavours", and just before guar gum, doesn't auger well for the chicken's relationship to the soup. I don't think a chicken even walked through it!
What I find alarming about the ingredient list, aside from the dearth of chicken, is that corn syrup solids heads the list. There is a great deal of research (some of it showing conflicting results) that these syrups, particularly high-fructose corn syrups, which most of them are, are associated with the increased incidence of obesity. Another concern around these types of mixes is the sodium content, and my comparative shopping yielded another puzzlement: While the powders came in at around 100 mg of sodium per 250 mL of prepared soup, one of the samples I examined (boasting 25% less salt), actually contained 527 mg of sodium. Go figure.
All of this raises the question "At what cost convenience?" While it's certainly true that adding some boiling water to a powder takes significantly less time than boiling a chicken, there are many so-called "convenience" foods that don't even save much time. There must be a point at which even the most time-deprived cook will admit it's not worth the health, and nutrition costs, never mind the money, to save a few minutes. As for the chicken broth, there are canned and packaged versions that are more expensive, but at least had a nodding acquaintance with a hen.
It's not that I underestimate the value of convenience. These days with both partner frequently working outside the home, time is money. But I think we need to do a careful assessment of the situation. I'm reminded that at the end of both World Wars people didn't have the option, or the cash, to send out for a pizza or stop off on the way home from work to pick up a fully-cooked meal. But when you think about it, you could easily broil some pork chops and nuke some potatoes and frozen veggies in half the time and at half the cost it takes to have the pizza delivered or stop off at the supermarket for a ready-made meat loaf. Just for the fun of it, time yourself and see how long it takes to whip up some pasta with tomato sauce and grated cheese.
Being a nutritionist I tend to put more importance on the control you have over home-made foods rather than time spent on preparation. When you make it yourself you can be sure that there's no shortening with all the trans fatty acids, no excess salt, no monosodium glutamate, no excess fat and sugar. What a deal! I don't mean to come across as the grumpy old lady I may seem--but honestly, if you're going to shell out big bucks for food, you should be saving a lot of time and nutrients. I remember when I was a young, working mother I'd feel guilty if I occasionally resorted to packaged macaroni and cheese. Today that package seems like it entails a lot of work compared to the ready-made frozen product that is popped into the microwave.
Thursday, June 11, 2009
Nutrition Misinformation: Dying from a misprint
Let me share with you one of the toughest things about being a registered dietitian/nutritionist. The toughest thing is reading, on an almost daily basis, nutrition information that is, quite simply, wrong.
Now don't misunderstand me. There are areas of nutrition where the absolute facts remain unknown, where the top experts in the field might disagree--for example, the role of sodium in elevated blood pressure. No, what concerns me are the errors of fact and this usually comes about from one of two reasons: 1) simple ignorance about nutrition and biochemistry, or 2) a hidden agenda.
An example of the former occurred recently when a national newspaper's reporter did a big story on detoxification. The topic itself (detoxification) actually introduces a third category of misinformation or is perhaps a combination of 1) and 2): the whole notion of detoxification or cleansing is nonsense but the health-food industry has done a pretty good job of convincing otherwise intelligent people that their body needs it. But, back to the misinformation. It came in the form of a declarative sentence that implied the writer actually knew whereof she spoke: "Dairy products", she wrote, "are one of the hardest food groups to digest." What sheer balderdash.
The notion of certain foods being "hard to digest" has been around for quite a while, usually ascribed to meat. There is not an iota of evidence to support the idea, and the stomach, unlike say, Olympic figure-skating judges, has no system for grading degrees of difficulty in the digestion process. The stuff gets dumped in there and the appropriate enzymes go to work and do their job. If you want to talk about a food that is "difficult" to digest, how about beans? Anyway, the writer says that dairy foods are banned from the "detox" diet and implies that her current diet is devoid of them as well. So there, based on a newspaper article, we have the possibility of thousands of women readers giving up the major source of calcium in their diet-and looking forward to future osteoporosis.
Another national newspaper story cites a "nutritionist" as recommending chocolate as a good source of iron and zinc. As an aside, let me point out that in most provinces the term "nutritionist" is not protected by law, so anybody can--and will--use the term/title...without having studied at an accredited university. Regarding the chocolate, which if it's dark, has a good level of antioxidants, there is no discussion of the difference in absorbability between "heme" iron (found in meat) and "non-heme" iron found in plant foods (poor absorbability), nor is there any mention of the size of a piece of chocolate you'd have to eat to get a significant amount of zinc. As it happens, the nutritionist who was quoted is one who advocates a diet free of animal foods, so perhaps her personal agenda/philosophy was influencing her judgment.
Then we have a blatant example of the hidden agenda. This is definitely the case with an article about a book by a so-called "diet doctor" who claims that cheese is addictive because it contains opiates. He compounds this bit of nonsense with the statement that cheese is 70% fat...completely wrong. Cheddar cheese, for example, is 32% fat. To begin with, calling this man a "diet doctor" is misleading in the extreme. He's an animal rights activist who happens to have an M.D. Either the reporter was unaware of this hidden agenda, or perhaps she bought into it herself.
Other bits of misinfo you might have run across include: spinach is a good source of calcium (it's not); the calcium in chocolate milk is unavailable to the body (not true--except for an extremely minor reduction); you need eight glasses of water a day (you don't; normal food and beverage intake can cover your needs nicely).
It would be nice if I could round off this story with a check list of what to look for when you're reading an article about nutrition, but that's easier said than done. First off you want to see if it's been written by or quotes a registered dietitian. That doesn't mean it can never be wrong; we make mistakes; we're human...but you're much more likely to get the facts from someone who has spent years studying the stuff. Other than that, the best I can tell you is to see if the information fits with your country's food guide. If it doesn't, then be skeptical.
Now don't misunderstand me. There are areas of nutrition where the absolute facts remain unknown, where the top experts in the field might disagree--for example, the role of sodium in elevated blood pressure. No, what concerns me are the errors of fact and this usually comes about from one of two reasons: 1) simple ignorance about nutrition and biochemistry, or 2) a hidden agenda.
An example of the former occurred recently when a national newspaper's reporter did a big story on detoxification. The topic itself (detoxification) actually introduces a third category of misinformation or is perhaps a combination of 1) and 2): the whole notion of detoxification or cleansing is nonsense but the health-food industry has done a pretty good job of convincing otherwise intelligent people that their body needs it. But, back to the misinformation. It came in the form of a declarative sentence that implied the writer actually knew whereof she spoke: "Dairy products", she wrote, "are one of the hardest food groups to digest." What sheer balderdash.
The notion of certain foods being "hard to digest" has been around for quite a while, usually ascribed to meat. There is not an iota of evidence to support the idea, and the stomach, unlike say, Olympic figure-skating judges, has no system for grading degrees of difficulty in the digestion process. The stuff gets dumped in there and the appropriate enzymes go to work and do their job. If you want to talk about a food that is "difficult" to digest, how about beans? Anyway, the writer says that dairy foods are banned from the "detox" diet and implies that her current diet is devoid of them as well. So there, based on a newspaper article, we have the possibility of thousands of women readers giving up the major source of calcium in their diet-and looking forward to future osteoporosis.
Another national newspaper story cites a "nutritionist" as recommending chocolate as a good source of iron and zinc. As an aside, let me point out that in most provinces the term "nutritionist" is not protected by law, so anybody can--and will--use the term/title...without having studied at an accredited university. Regarding the chocolate, which if it's dark, has a good level of antioxidants, there is no discussion of the difference in absorbability between "heme" iron (found in meat) and "non-heme" iron found in plant foods (poor absorbability), nor is there any mention of the size of a piece of chocolate you'd have to eat to get a significant amount of zinc. As it happens, the nutritionist who was quoted is one who advocates a diet free of animal foods, so perhaps her personal agenda/philosophy was influencing her judgment.
Then we have a blatant example of the hidden agenda. This is definitely the case with an article about a book by a so-called "diet doctor" who claims that cheese is addictive because it contains opiates. He compounds this bit of nonsense with the statement that cheese is 70% fat...completely wrong. Cheddar cheese, for example, is 32% fat. To begin with, calling this man a "diet doctor" is misleading in the extreme. He's an animal rights activist who happens to have an M.D. Either the reporter was unaware of this hidden agenda, or perhaps she bought into it herself.
Other bits of misinfo you might have run across include: spinach is a good source of calcium (it's not); the calcium in chocolate milk is unavailable to the body (not true--except for an extremely minor reduction); you need eight glasses of water a day (you don't; normal food and beverage intake can cover your needs nicely).
It would be nice if I could round off this story with a check list of what to look for when you're reading an article about nutrition, but that's easier said than done. First off you want to see if it's been written by or quotes a registered dietitian. That doesn't mean it can never be wrong; we make mistakes; we're human...but you're much more likely to get the facts from someone who has spent years studying the stuff. Other than that, the best I can tell you is to see if the information fits with your country's food guide. If it doesn't, then be skeptical.
Saturday, June 6, 2009
Water, water everywhere
The nonsense about needing to drink eight glasses of water each day is just that...nonsense. For openers, what the body does require is roughly two litres (or eight 8-ounce glasses) of fluids on a daily basis. That amount of fluid can be obtained even if nary a drop of water passes your lips. The more obvious sources of fluid are beverages like juice and milk, but even so-called no-no's like coffee and tea will add to your fluid intake. So, for example, if you drink an eight-ounce cup of coffee you will get the benefit of roughly six ounces of fluid, since coffee is a diuretic and will cause some of the liquid to end up in the kidneys, bladder, and eventually, down the drain. Even a bottle of beer or soft drink (God forbid) adds to one's fluid intake. On top of that, regular food contains fluid. Yes, stuff like vegetables, fruit, even bread, meat and cheese contains fluid (on a cheese label check the moisture content).
The notion that we need to drink eight glasses of water a day in order to be healthy is one of a long line of nutrition myths that are out there (nutrition myth-busting is one of the main rationales for this blog). Like many ideas about the health-giving properties of various foods, the alleged properties of so-called "pure" water have been greatly exaggerated. Celebrities and wanna-be's are seldom seen without a bottle of water in their hands. I once was preceded on the podium at a nutrition conference by a CEO (not a nutritionist or registered dietitian)of a famous company and his bottle of water accompanied him to and from the lectern like a security blanket...but he never touched a drop of the stuff. We'll touch on the idiocy of bottled water shortly, but for now I'll be happy if you just understand that we get liquid from almost everything we consume.
If someone had told me when I graduated as a dietitian some forty odd years ago that someday people would pay more for water than they do for an equal amount of milk, I'd have sworn they were crazy. Our culture has become obsessed with water and, to be fair, it's certainly better to drink a glass of water than a glass of sweetened soda pop, but people are wallowing in the stuff, for no good reason. Even elite athletes competing in hot climates can include any type of beverage--even caffeinated ones--in their regimen.
Wondering where the "drink eight glasses of water per day" myth originated, I found an old U.S. federal guideline that recommended one mL of water for each calorie that one burns...leading to the two litres per day for someone expending 2000 calories each day. The guideline did include the advice that most of that amount of fluid could be found in prepared foods...but that advice was pretty much ignored. I also think that the weight-loss industry's advice to try squelching hunger pangs with water came into play as well. In short...there is no evidence, none whatsoever, that we need to drink eight glasses of water daily.
On the down-side, you can have too much of a good thing, and that goes for water,too. On one end of the spectrum we have the damage done to those suffering from kidney or heart disease, in whom an excess of water will eventually overload the kidneys, upsetting the sodium/potassium balance. On the other end we have the elite athlete who takes water consumption to extremes and overdoses on the stuff. They can suffer from what is called hyponatremic encephalopathy (hypo meaning too little; natremic referring to sodium in the blood; encephalopathy meaning changes [swelling] in the brain) leading, in some cases, to death.
The old adage "stay ahead of your thirst" has been distorted so that even the non-athlete can risk hyponatremia. In one instance an opera performer was so convinced of the need for water to ease the stress on his larynx that he suffered from hyponatremia.
Drinking bottled water is not just silly, it's harmful on so many levels. First of all, it's expensive: with the money you save by drinking tap water (and most experts, when confronted with a blind-taste test, preferred it over bottled) you can support WaterCan, a charity that helps supply clean drinking water in developing countries (Google Margaret Trudeau). Secondly, it's really bad for the environment since the plastic bottles stay in dumps and land-fills for a VERY long time. Thirdly, tests have shown that there are more bacteria in many brands of bottled water than in tap water.
Summing up then, drink water if it's your cup of tea, but don't go overboard, don't believe the eight glasses nonsense, and give tap water a try...you might even like it.
The notion that we need to drink eight glasses of water a day in order to be healthy is one of a long line of nutrition myths that are out there (nutrition myth-busting is one of the main rationales for this blog). Like many ideas about the health-giving properties of various foods, the alleged properties of so-called "pure" water have been greatly exaggerated. Celebrities and wanna-be's are seldom seen without a bottle of water in their hands. I once was preceded on the podium at a nutrition conference by a CEO (not a nutritionist or registered dietitian)of a famous company and his bottle of water accompanied him to and from the lectern like a security blanket...but he never touched a drop of the stuff. We'll touch on the idiocy of bottled water shortly, but for now I'll be happy if you just understand that we get liquid from almost everything we consume.
If someone had told me when I graduated as a dietitian some forty odd years ago that someday people would pay more for water than they do for an equal amount of milk, I'd have sworn they were crazy. Our culture has become obsessed with water and, to be fair, it's certainly better to drink a glass of water than a glass of sweetened soda pop, but people are wallowing in the stuff, for no good reason. Even elite athletes competing in hot climates can include any type of beverage--even caffeinated ones--in their regimen.
Wondering where the "drink eight glasses of water per day" myth originated, I found an old U.S. federal guideline that recommended one mL of water for each calorie that one burns...leading to the two litres per day for someone expending 2000 calories each day. The guideline did include the advice that most of that amount of fluid could be found in prepared foods...but that advice was pretty much ignored. I also think that the weight-loss industry's advice to try squelching hunger pangs with water came into play as well. In short...there is no evidence, none whatsoever, that we need to drink eight glasses of water daily.
On the down-side, you can have too much of a good thing, and that goes for water,too. On one end of the spectrum we have the damage done to those suffering from kidney or heart disease, in whom an excess of water will eventually overload the kidneys, upsetting the sodium/potassium balance. On the other end we have the elite athlete who takes water consumption to extremes and overdoses on the stuff. They can suffer from what is called hyponatremic encephalopathy (hypo meaning too little; natremic referring to sodium in the blood; encephalopathy meaning changes [swelling] in the brain) leading, in some cases, to death.
The old adage "stay ahead of your thirst" has been distorted so that even the non-athlete can risk hyponatremia. In one instance an opera performer was so convinced of the need for water to ease the stress on his larynx that he suffered from hyponatremia.
Drinking bottled water is not just silly, it's harmful on so many levels. First of all, it's expensive: with the money you save by drinking tap water (and most experts, when confronted with a blind-taste test, preferred it over bottled) you can support WaterCan, a charity that helps supply clean drinking water in developing countries (Google Margaret Trudeau). Secondly, it's really bad for the environment since the plastic bottles stay in dumps and land-fills for a VERY long time. Thirdly, tests have shown that there are more bacteria in many brands of bottled water than in tap water.
Summing up then, drink water if it's your cup of tea, but don't go overboard, don't believe the eight glasses nonsense, and give tap water a try...you might even like it.
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