Category: Fact or Fiction?

The straight dope on nutrition myths, trends, and fads

Replacing High Fructose Corn Syrup with Sugar: Big Deal.

by Monica Reinagel, MS, LDN

It no longer matters whether it’s actually true that high fructose corn syrup (HFCS) is toxic to our livers, full of mercury, or to blame for exploding obesity rates.

The tales that have been told about HFCS have become so pervasive that it’s beginning to hurt sales.  Say no more! Manufacturers are now switching back to cane sugar–and using it as a marketing ploy.  “Sweetened with real cane sugar!” the packages proclaim.

Sugar is now a healthy ingredient. How Orwellian.

So, what have consumers gained? Well, many feel that products sweetened with sugar taste better. But are they healthier? In my opinion, no.

If we continue to over-consume highly sweetened foods and beverages, we will likely continue to see massive rates of obesity, diabetes, and heart disease.  Switching to foods and beverages sweetened with cane sugar rather than high fructose corn syrup is unlikely to have any measurable impact on public health–except perhaps indirectly.

Switching back to sugar will drive the price of these foods and beverages up. Maybe cost pressures will help shrink the ridiculously over-sized package and serving sizes. The only way anyone benefits from eating cane sugar instead of HFCS is by eating less of it.

See also “Scientists see little benefit in scramble to swap processed sweeteners for natural ones” in today’s Chicago Tribune.

Surprising news on how cooking affects vitamins

by Monica Reinagel, MS, LDN

microwave-ovenSolid information about how various cooking methods affect antioxidant content of vegetables is scarce…and much of it seriously out-dated.  Here are new findings, just published in the Journal of Food Science.

Microwave cooking redeemed

There’s a persistent urban legend that microwaving destroys nutrients. People often cite a certain, badly-designed study, in which broccoli was cooked (submerged in water) in a microwave for a ridiculously long period of time. Not surprisingly, the nutrient content was decimated.

However, this latest study shows that microwaving vegetables without water and only until tender appears to minimize nutrient loss. In general, dry cooking methods, like baking, grilling, or microwaving, protect nutrients better than boiling or pressure cooking.

In terms of nutrient losses, water is your worst enemy. Losses during pressure cooking were only about half of losses from boiling, however. And, unfortunately, they did not include steaming in their trial. (Why do researchers keep overlooking this common cooking method?!?)

Some vegetables hang onto their nutrients better than others

Regardless of cooking methods, certain vegetables seem to hang on to their nutrients better than others.  Beets, artichokes, green beans, and garlic seem to keep more of the antioxidant powers, regardless of how they are cooked.

Cooking actually increases antioxidant capacity in some vegetables!

Carrots, celery, and green beans actually were more potent in scavenging free radicals after they were cooked.  Researchers aren’t sure why but speculate that additional antioxidants might be “liberated” due to cell wall destruction during cooking, or that new antioxidant compounds might be formed by “thermal/chemical reactions.”

If you’d like to read the whole study, you’ll find it here.  But don’t get too hung up on the details.  Although how you cook vegetables does affect nutrient content, the most important thing, by far, is to eat a variety of vegetables, and plenty of them. Eat some of them raw and cook the rest however you enjoy them most!

How often should you eat?

by Monica Reinagel, MS, LDN

In a recent episode, I debunked the myth that eating more frequently keeps your metabolism revved up. Not only does skipping meals not shut down your metabolism, but there may be some benefits to going a bit longer between meals.

As I explained in that episode, going for four or five hours—or even longer—between meals will not affect your metabolism one whit. In fact, there are some good reasons to go longer than just a few hours between meals.

This article is also available as a podcast.

It takes about three hours for your body to finish digesting a meal. If you eat every two or three hours, as many experts now advise, your body will constantly be in what nutritionists call the “fed state.” This simply means that you are always in the process of digesting food.

If, on the other hand, you don’t eat again, you’ll go into something we call the “post-absorptive” state after about three hours. Several interesting things happen in the post-absorptive state, which continues for another 12 to 18 hours if you don’t eat again.

First, you begin tapping into your body’s stored energy reserves to run your engine. Your hormone levels adjust to shift your body out of fat-storage mode and into fat-burning mode. Hanging out in the post-absorptive state also reduces free-radical damage and inflammation, increases the production of anti-aging hormones, and promotes tissue repair. And, just to reinforce what we talked about last week, your metabolic rate remains unchanged.

But what about your blood sugar?

You’ll often hear people say that eating small, frequent meals helps to keep your blood sugar levels steady. And it does: It keeps your blood sugar steadily high.

Whoever said that your blood sugar levels were supposed to remain constant throughout the day, anyway? They’re not. They are supposed to rise after meals, as food is digested and converted into glucose, and then fall back to baseline as the glucose is taken up by the cells and used for energy or stored for future use.

Having your blood sugar level fall to baseline is not bad for you! In fact, having your blood sugar closer to baseline for more of the day helps to protect you from developing diabetes. Now, of course, it is possible for blood sugar to get too low. This is known as hypoglycemia. A lot of people self-diagnose themselves with this condition, but very few of them actually have it. Diabetics using insulin or folks with a medical condition called reactive hypoglycemia need to be careful about letting their blood sugar get too low.

But for the vast majority of us, managing blood sugar levels is about avoiding the peaks, not the valleys. If you experience headaches, fatigue, and other discomfort whenever you go more than two or three hours without eating, the problem is probably not that your blood sugar has gotten too low, but that it’s been too high.

Eating a lot of sweets, sweetened beverages, white bread, and other refined carbohydrates will cause your blood sugar to go up very high, very quickly. What goes up, must come down and the higher the spike, the more uncomfortable the plunge. The easiest way to make that feeling go away is to eat again. But if you eat more of the same kinds of foods, you’re simply getting back on the same roller coaster. And that roller coaster is on a fast track to type 2 diabetes.

To get off this roller coaster, eat foods that contain less sugar and more fiber, protein, and fat. I’m talking about whole grains, nuts, fruits, and vegetables. For pasta, go al dente.  Your blood sugar levels will rise more slowly and gradually, making the decline far less dramatic. And you may find that you don’t need to eat every three hours in order to feel well.

A word about hunger

The biggest problem you are likely to experience is feeling hungry, and this is not as big a problem as many of us have led ourselves to believe. When you are used to always being in the fed state, you tend to panic the minute you notice that your stomach is empty.

In fact, feeling hungry is not a medical emergency. Often, if you simply wait 10 minutes, the feeling will go away. Sometimes simply having a cup of tea or a glass of water is all you’ll need. Chewing gum is another great way to feel less hungry!  Allowing your stomach to be empty for an hour or two is really not that uncomfortable if you allow yourself to get used to the sensation. It’s also the perfect time to exercise. Exercising two or three hours after you eat will allow you to get the most out of your workout and, as a bonus, usually makes hunger pangs go away.

Please understand, I’m not advising you to stop eating or to starve yourself. I’m just saying going several hours without eating is not unhealthy. In fact, it can have some health benefits.

Originally published at QuickandDirtyTips.com

The China Study: Does Dairy Cause Cancer

by Monica Reinagel, MS, LDN

China_study_5 Dear Monica, I enjoyed your post on diet and breast cancer.  However, I cannot believe that you did not mention the direct relationship between the intake of casein (milk protein) and the growth of mammary tumors.  T. Colin Campbell in his The China Study outlines how this protein turns on tumor growth and the lack of it in the diet turns off cancer growth. “

Before saying anything else, let me first say that I completely support anyone who does not care to consume dairy products, for whatever reason.  Dairy is certainly not essential to a healthy diet. There are plenty of other ways to get calcium and vitamin D. (And those who do not consume dairy need to take care to be sure they do.)  I recently did a podcast episode on the pros and cons of dairy. You can listen to it here.

Now, to Campbell’s book: Lots of people commenting on this blog over the years have referenced this book as a definitive scientific rationale for various dietary practices.  Obviously, Campbell’s prose is compelling. But I have to be honest with you: The science behind his conclusions is less so.

You’re right: There are recent (2007) studies showing that milk increases the incidence of chemically-induced breast tumors in rats.  Interestingly, I also found a 2007 study showing that soy milk does the same thing. And another (2006) showing that fermented milk (yogurt) prevented tumors; and another (2001) showing that soy protein was preventive.

It appears that studies on things that cause or prevent tumors in rats injected with carcinogens might not provide a definitive answer to the question: Do dairy products cause breast cancer in humans? For that, it makes sense to turn to studies that compare what people eat to their risk of breast cancer.

Do dairy products increase breast cancer risk in humans?

The so-called “China Study” was a nutritional analysis conducted in rural China in the 1980s. This study purportedly found a link between the intake of animal protein and an increased risk of cancer and other disease.  In the intervening 20 years, many researchers have tested this conclusion, specifically with regards to dairy and breast cancer.  Here’s a brief sampling:

2007 American Journal of Clinical Nutrition (5000 subjects in England and Scottland): Childhood dairy intake was not associated with breast cancer risk.

2007 Cancer Epidemiology (2000 subjects in U.S.): Reduced breast cancer risks were associated with increasing milk consumption from ages 10-29, probably because of the cancer-preventive effects of vitamin D.

2006 Cancer Causes and Controls (5000 subjects in Italy): Consumption of milk and diary products did not increase breast cancer risk (and, in fact, consumption of skim milk slightly reduced risk).

2005 Journal of the American College of Nutrition (meta-analysis of 52 different studies):  Evidence does not support an association between diary product consumption and the risk of breast cancer.

2005 Nutrition and Cancer (study looking back 30 years and across 38 countries): No substantial effect of milk consumption on risk of breast (and other) cancers.

2004 American Journal of Clinical Nutrition (meta-analysis of 46 studies): No strong association between the consumption of milk or other dairy products and breast cancer risk.

2002 Journal of the National Cancer Institute (90,000 women followed for 16 years): “We found no association between intake of dairy products and breast cancer in postmenopausal women. Among premenopausal women, high intake of low-fat diary foods was associated with a reduced risk of breast cancer.”

2002 International Journal of Epidemiology (meta-analysis of 8 prospective studies involving 350,000 subjects in N. America and W. Europe): “We found no significant associations between intake of meat or dairy products and risk of breast cancer.”

Dairy is not essential to a healthy diet but it does not appear to cause breast cancer

Obviously, I would have had to have continued for quite a bit longer to work my way back to the China study. But there didn’t seem to be much reason to continue. (And I wasn’t cherry-picking, either…these are the studies that came up in response to my query!)

So, let me end this post the way I began:  Dairy products are not essential to a healthy diet. Feel free to eliminate them. But I don’t actually see evidence to suggest that doing so will reduce your risk of breast cancer. And, in fact, because dairy products are one of the only sources of vitamin D in the American diet, eliminating them might well increase your risk if you’re not careful to get that nutrient from other food sources.

Let’s Put This New Fructose Study In Perspective

by Monica Reinagel, MS, LDN

A recently published study is going to fuel the hysteria over high-fructose corn syrup. It’s a terrific study. But, contrary to the headlines you are sure to see over the next days and weeks, it does NOT prove that high fructose corn (HFCS) syrup is the cause of the obesity epidemic. Let’s take a closer look.

Researchers at the University of Florida found that rats who were fed a diet that was very high in fructose eventually became resistant to the hormone leptin.  Leptin is a hormone that regulates your appetite and disposition toward weight gain.  In the second half of the study, they switched the leptin-resistant rats to a high-calorie (high-fat) diet. The rats ate a lot more and gained a lot more weight than rats who had not been on a high-fructose diet. (Read more about the study: “Fructose hampers hormone that controls appetite.“)

Now, what does this tell us about the effects of high-fructose corn syrup on humans? Very little.

Aside from the obvious issue (the study was done in rats, not humans), the study had absolutely nothing to do with high fructose corn syrup. The diet that brought about leptin resistance was about 60% fructose, and contained no other form of sugar.  The typical (awful) American diet contains about 35% sugar, about half of which (roughly 17%) is in the form of fructose.

Incidentally, if every bit of HFCS in the food supply was replaced by regular old cane sugar, our fructose intake would still be around 17%.  That’s because high fructose corn syrup contains about the same amount of fructose as sugar.

Like the best research studies, this one poses far more questions than it answers. For example, I’m dying to know whether you’d get the same results at 50% fructose. Or 40% or 30%. What’s the threshold at which the effect starts to set in?

Secondly, I’d love to know whether you’d get leptin resistance with similar amounts of glucose or sucrose?  In other words, how much of this effect is specific to fructose and how much is just sugar? What’s more significant: the amount of total sugar in the diet or the amount of fructose? How does dietary fat affect things? (In the study, the rats ate an extremely low-fat (5%) diet and the fat was lard.)

I imagine that researchers are queuing up to design studies that will answer these questions and more. (And we’re still only talking about rats…)

Those who read this blog (or listen to my podcast) know that I think the hysteria over high-fructose corn syrup is misplaced. We should be alarmed by the amount of sugar in the American diet and what it is doing to our health. I think it probably is directly connected to our rising rates of obesity, whether through leptin resistance or other means. But I don’t think it’s worth worrying about high-fructose corn syrup, per se, while we’re still getting 35% of our calories as sugar.

This whole thing reminds me a little of people who are freaking out about gas prices and dependency on foreign oil.  They’re trading in their cars for models that will improve their gas mileage from 27 to 30 mpg.  But it never occurs to them to drive fewer miles.

Here’s what we all agree on

I am sure that large quantities of fructose will cause health problems in rats and humans. I’m pretty sure that large quantities of any form of sugar will do that. Of course, the specific problems that develop will vary depending on what type of sugar you’re over-consuming. Fructose is hard on the liver while glucose is more challenging to the pancreas.

But rather than argue about which form is more dangerous, what about working the problem from the other end of the equation? I”m talking about the “large quantities” part of the sentence.

Eat less sugar and you probably don’t need to worry about HFCS

The World Health Organization recommends that you limit your intake of added sugars to 10% of calories.  They’re not talking about sugars that are found naturally in whole foods, like fruit or milk. They’re talking about refined sugars in things like candy, baked goods, soft drinks, and condiments.

For most Americans, this would mean cutting their sugar intake by two-thirds.  Whether or not HFCS is really that much worse than other forms of sugar (I’m still not convinced it is), I’m pretty sure that if we simply cut our consumption to a reasonable level, it simply wouldn’t matter.

Call me crazy.

Breast cancer and diet: Is there a link?

by Monica Reinagel, MS, LDN

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Google “breast cancer diet” and you’ll find dozens, if not hundreds, of links to diet plans that claim to reduce your risk of breast cancer. But can the right diet really prevent breast cancer or improve your chance or survival if you have breast cancer?

Unfortunately, we just don’t know for sure. One of the most controversial questions is whether or not a low-fat diet reduces the risk of breast cancer.  Big population studies suggest that fat consumption is linked to breast cancer risk. That is, populations with higher fat intake have higher breast cancer rates. But clinical trials designed to test this theory have been inconclusive.

Soy is another area of controversy.  Soy contains phytoestrogens that can act as weak estrogens in the human body. Some believe that soy estrogens may stimulate the growth of estrogen-sensitive cancers. Others argue that the weaker soy estrogens are protective because the block the activity of stronger human estrogen.  Studies have yet to convincingly prove the case one way or another but to be on the safe side, most experts recommend soy foods be consumed in moderation.

People who eat more fruits and vegetables and less red meat have a reduced risk of cancer overall–although scientists have so far been unable to pinpoint exactly which foods or combinations of foods may be responsible.  There’s no doubt that fruits and vegetables are full  of anti-oxidants and cancer-fighting nutrients. But so far, the protective benefits of individual foods or nutrients have only been shown in the laboratory or in animals, not in humans.  Studies on nutritional supplements have been particularly disappointing.

Despite what the magazines and book authors may claim, there is no convincing proof that any particular diet or combination of foods reduces your risk of breast cancer specifically. But that doesn’t mean there’s nothing you can do. In fact, there are three things you can do that will DEFINITELY reduce your risk of breast cancer and improve your odds of survival if you are diagnosed.

The best breast cancer prevention diet

The best breast cancer prevention diet is the one that helps you maintain a healthy weight.  Being overweight is a primary risk factor for breast cancer. In addition to containing cancer-fighting compound, fruits and vegetables are low in calories. Eating more fruits and vegetables can help you lose weight and improve your nutritional status at the same time.

The next most important thing you can do to reduce your risk is to limit your consumption of alcohol to no more than one drink per day.  If you do drink alcohol, be sure that you are getting enough folic acid. A large study conducted in Australia suggests that adequate folic acid intake can negate the increased breast cancer risk associated with moderate alcohol consumption.

And, finally, your breast cancer prevention diet should include at least 30 minutes of physical activity every day. Studies show that moderate exercise is highly protective against breast cancer and vastly improves survival rates among women with breast cancer.

More resources:

Does diet affect breast cancer risk? Journal of Breast Cancer Research
Recommendations for Cancer Prevention American Institute of Cancer Research
Foods that Fight Cancer American Institute of Cancer Research
Diet and Lifestyle and Survival from Breast Cancer Sprecher Institute for Comparative Cancer Research

Obese America: Is Corn Syrup to Blame?

by Monica Reinagel, MS, LDN

In a recent discussion about fructose and heart disease risk, a reader brought up the issue of high fructose corn syrup and I promised to address this hot topic in a new post.  Let me just say up front that a lot of people are likely to disagree with my view on this subject. But what’s a blog without a little controversy once in a while?

For those who haven’t been following along, there has been a lot of heat around the widespread use of high fructose corn syrup in processed foods.  Manufacturers can save big bucks by using HFCS in place of more expensive table sugar, or sucrose. (One reason that HFCS is so much cheaper than sugar is that corn is heavily subsidized by our government via the Farm Bill, but that’s another story!)

Many products (most notably soft drinks) that used to be sweetened with regular sugar now use HFCS instead. It’s also true that the increased use of HFCS in the food supply roughly corresponds to rising obesity rates.  And there is research suggesting that fructose may be more readily stored as fat than glucose, which is metabolized differently.

These facts have led many to conclude that the rise of HFCS in industrial food production has led to our current national health crisis of obesity and related disorders (such as diabetes and heart disease).  Not surprisingly, some savvy marketers have even managed to position sugar as healthy, touting virtuous HFCS-free soft drinks that are sweetened with good old fashioned sugar. But hang on a second.

High fructose corn syrup sounds like it would be high in fructose, right? The truth is that it contains roughly the same amount of fructose as…regular sugar.

Sucrose is about 50% fructose and 50% glucose. Regular corn syrup almost entirely made up of glucose. In order to make it a more appropriate substitute for sucrose, raw corn syrup is enzymatically treated to convert some of the glucose into fructose, bringing fructose/glucose ratio up to that of regular sugar.

Look, I’m not saying HFCS is good for you.  All I’m saying is that HFCS is not higher in fructose than sugar…it’s just higher in fructose than regular corn syrup.  Personally, I think the rise in obesity rates has less to do with the influx of HFCS into the food supply and more to do with our increased consumption of soft drinks and other calorie-dense foods.  As portion sizes (of everything) get bigger, our calorie intake increases and we gain weight.

Will Taking Vitamins Improve Your Health?

by Monica Reinagel, MS, LDN

It’s a hotly debated question among health researchers. New studies come out every year but we don’t seem to be getting any closer to a definitive answer. About half the studies show that people who take vitamins are healthier and the other half find that taking vitamins makes no difference…or, in a few cases, actually make things worse. I have to admit that I’ve held, at various times in my career, different views on the question.

(See also this Nutrition Diva podcast episode on Multivitamins.)

We know that the nutrients in food play important roles in keeping us healthy. Calcium helps prevent osteoporosis, folic acid helps prevent neural tube defects, antioxidants repair cellular damage, and so on down an ever expanding list of nutrients and co-factors. It seems like supplementing an (imperfect) diet with additional nutrients is a reasonable way to make sure we’ve got our bases covered.

If we’re talking about a 25¢ one-a-day multivitamin, I guess the vitamin as insurance policy makes sense. But it’s gotten way more complicated than that. For one thing, the list of “basic” nutrients gets longer and longer. A multivitamin used to involve 15 or so nutrients (A, B, C, D, E, and a few minerals.) Now, a typical multi boasts several dozen compounds, from astaxanthan to vanadium. But it’s still not truly complete. Next to it on the shelf you’ll find the anti-oxidant booster, the bone health formula, the immune booster, plus the the formulas for your eyes, skin, nails, hair, memory, joints, and prostate. Before you know it, you’re forking out a couple hundred bucks and month and swallowing a fistful of vitamins every day. But are you getting your money’s worth?

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