Category: Nutrition in the News

My take on the latest diet and nutrition headlines.

Probiotic Confusion

by Monica Reinagel, MS, LDN

Probiotics Last week, I answered a question from a reader who had seen a study showing that probiotic supplements reduced cold and flu symptoms in children. He reasoned that eating yogurt every day might be a good step and wondered how much he’d have to eat to get a similar “dose” of probiotics.   To answer his question, I compared the number of active cultures in a typical probiotic supplement to the number of active cultures in a typical yogurt.

But I missed an opportunity to clarify what I think is a widespread misunderstanding about probiotics. Many people think of all probiotic supplements and foods as being somewhat interchangeable. They’re not.

Probiotics: an umbrella term for thousands of different bacteria

In terms of labeling foods and supplements, the FAO/WHO defines probiotics as “Live microorganisms which when administered in adequate amounts confer a health benefit on the host.”  That’s any health benefit.

There are hundreds of different strains of lactobacillus bacteria and they offer a variety of potential health benefits to humans. Some colonize the large intestine, others live in the lining of the stomach, still others have an affinity for the mucus membranes in the nose.  Of the many strains likely to colonize the large intestine, for example, some may improve gut immune function, others digest complex sugars, others may benefit the host by producing vitamin K.

There are also lactobacillus bacteria that don’t do much of anything to improve or defend your health. These, while harmless, would technically not be classified as probiotics–although they might still be considered “live and active cultures.”

Foods versus supplements

Most probiotic foods contain a variety of bacterial strains–your average supermarket yogurt might contain six different bacterial strains. And the lactobacillus bacteria found in yogurt are not necessarily the same as those found in other fermented foods like kefir or kim-chi.

See also: A World Tour of Lactobacillus Bacteria

Many of the studies you read about use “boutique” strains that are not likely to be found in any traditionally-fermented foods. In the case of the study I mentioned above, for example, they used two trademarked strains called Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07.

Is there any point to consuming probiotic foods?

I still think there are general health benefits to eating traditionally-fermented foods like yogurt, kefir, kim-chi, kombucha, sauerkraut, and miso. Eating a variety of fermented foods, which provides a wider variety of bacterial strains, might offer a wider range of benefits.

But we need to be careful about assuming that the findings on a particular strain apply to all probiotics and probiotic foods.  If you’re going for a specific therapeutic benefit, such as protecting against side effects while taking antibiotics or improving flu resistance, there’s no guarantee that yogurt or any other fermented food will contain the same bacteria as were used in a particular study.

Similarly, when shopping for probiotic supplements, pay attention to the individual strains in that supplement and how they compare with the strains used in various studies you might be responding to.



What’s so magical about the Mediterranean Diet?

by Monica Reinagel, MS, LDN

Forget the mouse studies. After a couple weeks of controversial and much-contested rat studies on the effects of carbohydrates on various aspects of metabolism and disease, here’s a study involving 200 newly-diagnosed, diabetic humans.  Half were told to follow a Mediterranean-style diet, rich in vegetables, whole grains, and monounsaturated fats from poultry, fish, and olive oil and limiting carbohydrates to 50% or less of total calories.

The other half were assigned to a “low-fat” diet, which also emphasized whole grains and discouraged sweets and high fat snacks. Fat was limited to 30% or less of calories and saturated fat to 10% or less of calories.

After four years, the Mediterranean group had lost more weight and was only half as likely to need anti-diabetic medications.

What’s the real difference here?

Notice that the macronutrient distributions between the two diets are not all that different. The Mediterranean diet was not terribly low in carbohydrates (although it’s being described in media reports as a “low-carb” diet). The low-fat diet isn’t really all that low in fat. The two percentages certainly aren’t mutually exclusive. In fact, it’s entirely possible that the distribution of fats, proteins, and carbohydrates between the two groups was very similar.  Nor can we necessarily chalk it up to refined versus complex carbohydrates.  Both groups were instructed to favor whole grains.

Perhaps it was just a matter of what the dieters were told to focus on.  The Mediterranean group was told what to eat: vegetables, fish, grains, olive oil. The low-fat group were told what to avoid: sugary snacks and high-fat foods.  Could it be as simple as casting dietary recommendations in terms of positives instead of negatives?

Can yogurt protect you from the flu?

by Monica Reinagel, MS, LDN

Can Yogurt Reduce Risk of FluQ. I recently read about a study showing that probiotics protected kids from getting the flu. It seemed like a pretty powerful study in favor of the health benefits of yogurt, at least in kids. Do you have any recommendations for a reasonable “dose” of yogurt would be for an adult?

A. Yes, I noted that study with interest as well. The kids (about 300 of them, aged 3 to 5) were taking probiotic supplements or placebo pills twice a day. The kids getting the probiotics had about half as many fevers, coughs, and runny noses, took fewer prescriptions and missed fewer days of school.

We should note that the study was funded by a company that makes probiotic products.  That said, the results were published in a peer-reviewed journal (Pediatrics) so the study design apparently passed muster.

See also: Can we Trust Industry Funded Research?

There’s no RDA for probiotics for kids or adults so it’s hard to say what a good”dose” might be. Most probiotic supplements contain 10 to 20 billion active cultures per dose at the time of manufacture. Yogurt that carries  the “Live and Active Cultures” seal is certified to contain at least 100 million cultures per gram at the time of manufacture, which translates into about 22 billion live cultures in an eight ounce cup of yogurt.

So, I’m thinking that a single serving of yogurt every day would be a reasonable start for kids and adults. But the amount of sugar (often high fructose corn syrup) in sweetened yogurts is shocking. I’d advise you to steer clear of sweetened (and artificially-sweetened) yogurts and go for the plain yogurt. Sweeten (if you must) with fruit or a drizzle of honey.

Can yogurt protect you (or your kids) from getting the flu this season? Might help and can’t hurt (unless you’re lactose intolerant).




New Guidelines for Added Sugars

by Monica Reinagel, MS, LDN

The American Heart Association has come out with new challenge: Limit added sugars to no more than 25g (about 6 tsp) per day for women and 36g a day for men.  Right now, we consume on average around three and a half times that much.

Where did they come up with the numbers?

The AHA reasons that “excessive consumption of added sugars is contributing to over-consumption of discretionary calories,” which, in turn, leads to obesity and increases heart disease risk.  Discretionary calories are the ones we eat just for the fun of it and not necessarily to meet our nutritional needs. The USDA dietary guidelines recommend that these discretionary calories should be limited to 10% of total calories. The AHA figures that added sugars should make up no more than half of the discretionary calorie allowance.

This new recommendation sets the bar on added sugars even lower than the “10% of calories” limit that was suggested a few years back by the World Health Organization.

True confessions

I have to be perfectly honest with you: I’d have to make some changes in my diet in order to limbo under the new 25g bar. I don’t drink soda, which is the primary source of added sugars for most Americans.  And I don’t eat a whole lot of processed foods.  But I do enjoy ice cream. I often bake muffins or make granola for breakfast. I have a square of chocolate after dinner most nights. It adds up quickly.

What counts as an added sugar?

Of course, it depends on what you count.  Most sources agree that naturally occurring sugars in fruit and dairy don’t count as added sugars.  I agree.

Many try to argue that “natural” sugars like honey or molasses also shouldn’t count, but I don’t see why.  Honey, molasses, maple syrup, agave syrup, refined white sugar, brown sugar, and organic cane sugar are all concentrated sources of sugar. Some are more refined than others, but the nutritional and metabolic impacts are similar.  In other words, I’m not off the hook simply because I make my granola with honey. It’s still a source of added sugar in my diet. Here’s my recipe for granola by the way.  Each serving contains 9g of added sugar.

Adding it up

It’s fairly easy to keep track of the sugars that we add ourselves, whether at the table or in the mixing bowl. The real trick is keeping track of the sugars in processed foods. Check the ingredient lists for sugar and all its aliases (such as corn sweetener, corn syrup, dextrose, glucose, high fructose corn syrup, honey, maltose, malt syrup, molasses, sucrose, and syrup). The higher up these are in the list, and/or the more of them you see listed, the more sugar the food contains.

The nutrition facts label has a line for “total sugars” and you can use this to keep a tally, but keep in mind that this number includes the natural sugars in fruit and dairy as well as added sugar (honey, etc.).

For example, a container of fruited low-fat yogurt contains 47grams (!) of sugars. However, a container of plain low-fat yogurt contains 17g of naturally-occurring sugar.  That means that the fruited yogurt has 30g of “added” sugars.  Oops…you’re already over the limit.

It’d be a bit trickier to sort out the natural versus added sugars in something like a store-bought oatmeal raisin cookie. But you get the idea.

So, how hard would it be for you to limit yourself to 25 grams of added sugar a day? How hard would it be if you also avoided artificial sweeteners?

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.

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!

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.

Vitamin D: Now I’m a believer

by Monica Reinagel, MS, LDN

One of the most electrifying sessions I attended at Andrew Weil’s Nutrition and Health Conference in April was one given by Dr. Michael Holick on Vitamin D.  Dr Holick is a well-known, even notorious, name in nutrition research circles. He’s been insisting for years that vitamin D deficiency is far more wide-spread and dangerous than anyone realizes and he has a reputation (which he himself promotes!) of being a bit of a kook.

A few years ago, he was famously booted from the Boston University dermatology faculty for making heretical statements about the benefits of moderate UV exposure (which stimulates the production of vitamin D in the skin) and has been chided and derided by the dermatology establishment ever since.

I thought I had a pretty good idea of what to expect from Holick’s presentation; it would be all about the miraculous powers of vitamin D and the dire consequences of deficiency.  I tend to take these sort of Wonder Nutrient presentations with a grain of salt.  When you spend your whole life researching a single compound–like many of these researchers do, I think you can start to lose your sense of perspective. As the old saying goes: When you’re holding a hammer, everything starts to look like a nail.

The evidence is always reasonably compelling. And by the end of every Wonder Nutrient presentation, you find yourself thinking, I really should start taking that, and I should probably start recommending it to my patients, too. The problem is that after a few dozen of these presentations, you (and your patients) have a list of 40 nutrients that you “need” to be taking.

It’s probably a backlash against too many Wonder Nutrients but, as many of you know, I’m not all that big on dietary supplements. Whenever possible, I think it’s better to meet your nutritional needs with actual foods. I myself take very few supplements.  And I have become immune to the persuasive power of Wonder Nutrient lectures.

And yet, after hearing Dr. Holick’s presentation, I literally stopped on my way back to the hotel to buy a bottle of vitamin D (1000IU).

First, I’ve gotta say, if you ever have a chance to see this guy speak, don’t miss it. All 1,200 of us in the audience were blown away (300 slides in 50 minutes). But it wasn’t just his over-the-top presentation that made me break my ban on Wonder Nutrients.  It was the cumulative impact of the data.

To me, the most compelling reason why vitamin D is really in a category of its own, and why most people need far more vitamin D than they can ever get through their diet, is this: Our bodies were not designed to meet our vitamin D requirements through dietary sources–we evolved to produce vitamin D in our skin, when the sun hits it.

That’s why people who originally lived further from the equator have lighter skin–it allows more UV rays to penetrate, which compensates for the weaker rays at those latitudes. The traditional diet of the northern and southern latitudes is also more likely to include oily fish, the richest dietary source of vitamin D.

But now, most of us spend most the daylight hours indoors. Any skin that is showing is slathered in sunscreen to prevent skin cancer and wrinkles. We don’t eat much cod liver.  We get most of our vitamin D from fortified dairy products and vitamin supplements, but it’s not nearly enough to meet our requirements.

Holick claims that the majority of Americans are chronically and dramatically D-deficient.  Among those at particular risk are those with dark-skin, the elderly, the obese (because vitamin D tends to become trapped in fat cells) and anyone living about the 35th parallel (which runs through Arizona and Georgia).  That is the latitude above which it is impossible to manufacture vitamin D in the winter months, even (as Holick to colorfully pointed out) you were to stand on the roof stark naked from noon to 3pm every day.

So what?

Every cell in the body has a receptor for vitamin D. Low blood levels of vitamin D are strongly linked to increased rates of cancer, osteoporosis, chronic pain syndromes, multiple sclerosis, rheumatoid arthritis, Type I diabetes, and  hypertension.

In fact, if you chart deaths from colon cancer, prostate cancer, or multiple sclerosis geographically, you can pick out the 35th parallel by eye because the difference in mortality rates is so much higher above that line. (Deaths from multiple sclerosis are 100% higher above 37 N. than below it! )

There’s much more to Dr. Holick’s argument (about 280 slides worth) but suffice it to say, I’m a believer.  Vitamin D is now one of only three nutrients I take as supplements (along with fish oil and calcium).

Dr. Holick and others are compaigning to have the government recommendations for vitamin D increased from the current recommendation of 200 – 600IU (depending on your age) to 1,000IU of vitamin D3 (cholecalciferol) for everyone. Based on his data, I support that recommendation.

Note: Vitamin supplements containing vitamin D2 (calciferol) are only about half as potent as D3 (cholecalciferol). Also, be cautious with sources that contain both vitamin D and vitamin A (such as supplements or cod liver  oil) and be sure that the amount of vitamin A (retinol) that you’re getting from all sources does not exceed 10,000IU.

For more information on vitamin D and health, visit Dr. Holick’s site at http://vitamindhealth.org/