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Looking For the Truth on Fructose? Keep Looking.

by Monica Reinagel, MS, LDN

I really don’t get it. Fructose is the dietary scapegoat of the decade, blamed for everything from obesity to liver disease. Never mind that most high fructose corn syrup is in actuality no higher in fructose than regular table sugar. Never mind that the increase in fructose consumption (the so-called smoking gun) over the last ten years was accompanied by an equivalent increase in glucose consumption. Never mind that pure fructose is not found in nature or in the normal human diet–it is virtually always consumed in combination with other sugars.

There is so much myth and hysteria circulating about fructose, you would think some solid scientific inquiry would help clarify the situation. But how are we ever going to figure out what part (if any) fructose per se plays in our health problems when researchers continue to design studies that fail to isolate the variables?

For example, this latest study, published in the American Journal of Clinical Nutrition compared a diet that was high in fructose and and also provided a third too many calories with a diet that contained less fructose and the proper number of calories. Those on the “high fructose” diet experienced several unfavorable changes in their blood lipid profiles.

So what? How many of those effects were due to simply overeating? Why not compare two diets with the same number of calories but differing amounts of fructose? And please don’t show me studies that compare diets containing only fructose versus diets containing only glucose because these type of diets don’t occur outside a laboratory.

Is too much sugar to blame for many of our health woes? You bet. Is fructose metabolized differently than glucose and other sugars? For sure.  Is fructose poison to our bodies? Fructose is like any other sugar molecule: when refined, concentrated, and consumed in excess quantities, it’s not good for you.

Want to improve your health? Cut down on added sugars–that includes table sugar, HFCS, maple syrup, honey, agave nectar, fruit juice concentrates, and foods made with any of these. You’ll be cutting down on fructose in the process–if that makes you feel better.

But I’ve yet to be convinced that fructose is harmful except in cases where sugar (in general) makes up too large a proportion of calories. In these cases, the effects of fructose on the liver and blood lipids are simply one of the mechanisms by which too much sugar damages human health–no more or less dangerous than any number of other mechanisms, such as the effect of glucose on blood sugar and insulin levels, or the effect of excessive calorie intake on body fat and weight.

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!

Sodium and Potassium: What’s the Relationship?

by Monica Reinagel, MS, LDN

Q. Please comment on the relationship between potassium and sodium.  How can I be sure that I’m not getting too much potassium as I continue to decrease the amount of sodium in my daily diet? 

A.  Decreasing the amount of sodium in your diet won’t necessarily affect the amount of potassium you’re getting but it will probably increase the ratio of potassium to sodium in your diet–and many believe that this is a good thing!

Sodium and potassium have complementary functions in the body, helping to regulate things like fluid balance and blood pressure.  We need to maintain a precise balance of potassium and sodium in our cells but our intake of potassium and sodium may vary greatly from day to day. Therefore, the body has systems that tightly regulate this balance, excreting any excesses into the urine.

The potassium/sodium content of our modern diet is radically different than the diet our ancestors ate–and many believe that this contributes to a lot of our modern health problems. Potassium is found in fruits and vegetables; most of the sodium we eat comes from processed and packaged foods.

By some estimates, our ancestral (pre-industrial) diet had a potassium to sodium ratio of at least 3:1, meaning that it contained about three times as much potassium as sodium.  However, as we’ve come to eat more and more processed foods and less fruits and vegetables, our intake of potassium has declined and our intake of sodium has skyrocketed.  The typical potassium to sodium ratio today is 1:3 (three times as much sodium as potassium) or exactly the inverse of our ancestral diet.

Whether or not the potassium/sodium ratio theory is correct, reducing your intake of processed foods and increasing your intake of fruits and vegetables is a great health upgrade for your diet!  I think  its pretty unlikely that you will get too much potassium from foods. Most Americans get about 2500 to 3000 milligrams per day; the recommended intake is about twice that!

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

Farmed Salmon Gets an Anti-Inflammatory Makeover

by Monica Reinagel, MS, LDN

The latest nutrient data from the USDA shows that farmed Atlantic salmon has undergone what is perhaps the most dramatic nutritional makeover in history.

Salmon is known for being rich in anti-inflammatory omega-3 fatty acids and, as you know, the anti-inflammatory diet is very big these days. (The recognition of inflammation as a key factor in heart disease and other common diseases was hailed by Time Magazine as one of the Top Ten Medical Breakthroughs of 2008.)

In 2006, I caused quite a stir by pointing out in my book, The Inflammation Free Diet Plan, that farmed salmon was actually highly inflammatory. When I first published the IF Ratings, a 3-ounce serving had an IF Rating of -491.

As I (and others) pointed out, farmed Atlantic salmon was quite high in arachidonic acid, an inflammatory fatty acid from the omega-6 family. The problem was that farmed salmon were being fed a diet rich in omega-6 vegetable oils rather than a more natural diet of omega-3 rich fish and algae. As a result, their flesh was unnaturally high in omega-6 fats.

Fish farmers apparently got the message! Big changes in aquaculture practices have resulted in farmed Atlantic salmon that is much lower in arachidonic acid…so much lower, in fact, that the most recent samples tested by the USDA had an IF Rating of +775 per 3 ounce serving!

So, after years of warning people to avoid farmed salmon, especially if they were trying to follow an anti-inflammatory diet, I’m now putting farmed salmon back on the menu!

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