My view on low carb diets? It's complicated.

Q.    From reading your blog it seems that a lot of your readers back low carb diets.  Being a student studying nutrition, everything I have read has said that a low carb diet is terrible for your health.  Can you address your views on this in your blog?

A.   It's something that comes up a lot on the blog and always seems to elicit very strong opinions.  Several regular commenters are quite ardent about the evils of carbohydrates.  My views are somewhat more moderate.  I do think that refined carbohydrates are a big part of the problem with the Western diet.  I think that overconsumption of refined carbohydrates (especially in the context of a sedentary lifestyle) contributes to obesity, diabetes and related metabolic issues, and heart disease. 

However, I don't think it's necessary to eliminate all grains and starches from the diet in order to lose weight and/or be healthy. Regardless of how cavemen ate, I think a diet that contains balanced amounts of good-quality carbohydrates, fats, and proteins is ideal for modern humans. Nonetheless, some people have found a low-carb lifestyle to be life and health-changing.

 I'm surprised to hear you say, though, that "everything I've read has said that a low carb diet is terrible for your health."  Although the studies over the years have been mixed, there are plenty of studies showing that low-carb regimes are at least as effective in producing weight loss, controlling blood sugar, and even improving heart risk factors as low fat regimens. 

For example, just this week, a study came out saying that low-carb and low-fat diets were equally effective in helping diabetics lose weight and control their blood sugar. Plus, the low-carb dieters had a greater increase in HDL ("good") cholesterol after one year on the regimen.

Obviously, it's way too simplistic to characterize carbs (or low-carb diets) as good or bad. What kind of carbs?  What's the rest of the diet look like? What's the overall lifestyle look like? It's not a one-size-fits all situation.  And all low-carb diets are not the same. For more of my views on this complex topic (and those of lots of opinionated readers), see also these related posts:

Dietary Dogma

A visit to Low Carb Land

Another log on the low-carb fire

People who eat more carbs tend to be thinner?

Pearled vs. Hulled Barley?

Q. What is the nutritional difference between pearled barley and hulled barley?

A. I found this helpful information in the Food Dictionary at Epicurious.com:

"Hulled (also called whole-grain ) barley has only the outer husk removed and is the most nutritious form of the grain. Scotch barley is husked and coarsely ground. Barley grits are hulled barley grains that have been cracked into medium-coarse pieces. Hulled and Scotch barley and barley grits are generally found in health-food stores. Pearl barley has also had the bran removed and has been steamed and polished. It comes in three sizes — coarse, medium and fine — and is good in soups and stews."

So, pearled is more processed than hulled barley. You can see the nutritional difference in the entries for pearled barley and hulled barley here on NutritionData.com.

Red meat and cancer link questioned

I'm sure this won't end the debate over the nutritional merits or demerits of meat, which continues here (Meat and mortality) and here (Saturated fat no longer the villain?).  

But the authors of a widely-cited study linking the consumption of red meat to colorectal cancer now say their analysis contained "errors and omissions" and overstated the links. The study was conducted by the American Institute for Cancer Research (AICR) and World Cancer Reserach Fund (WCRF). See Errors found in cancer report for more details.

That the National Cattleman's Beef Association (NCBA) objected to the AICR/WCRF study is not surprising.  That the USDA decided to defer to the judgment of the AICR/WCRF over that of the NCBA in the matter is also not surprising.

That the AICR/WCRF met with the NCBA, acknowledged that their criticisms had merit and agreed to inform the USDA of errors is, well, surprising.

To me it says that 1) we all need to remember that no "study" ever really closes the case; 2) industry-funded research is not ALWAYS less reliable than "independent" research; 3) ideology can be just a potent a bias as commercial interest; and 4) true scientists are more interested in getting it right than getting the "right" results.

All in all, the apparent cooperation and good faith between the parties adds up to a triumph for the scientific process in which we all try to get closer to the truth.

Canning and preserving: not for free-wheeling types?

 Canning is chic!  A perfect storm of conditions (recession + home gardening boom + local foods movement) has led to a huge revival in the old-fashioned art of preserving foods.  Food safety experts worry that the next wave of food-borne illness could may come out of America's well-meaning kitchens rather than our industrial packaging plants.

Improper handling and processing can easily lead to the growth deadly bacteria in home-canned goods. This is no time for improvising or guesswork. It's important to follow canning procedures to the letter to ensure proper sterilization and seals.

If you're not the read-the-instruction-manual type, you might want to limit your food preservation projects to drying and/or freezing.  If you're determined to can, be sure you know what you're doing. You'll find free publications and even a self-guided home study course at the National Center for Home Food Preservation.

Eating more frequently: Going out of vogue?

For years now, dieters have been counseled to eat more frequently in order to help control hunger, balance blood sugar, and keep the metabolism burning. I've had my doubts about the scientific validity of this advice, in particular, the part about the effect of meal frequency on metabolism.

I recently did two podcasts on the topic. In "Metabolism Myths" I conclude that eating more frequently has absolutely no effect on your metabolism.  In "How Often Should You Eat?" I talk about the effect that frequent eating has on blood sugar levels (perhaps not what you think) and the possible benefits of going longer between meals.

So I was interested in this recent article in Nutrition Reviews which tried to evaluate whether meal frequency has an impact on weight loss or maintenance efforts. Although the authors found the evidence to be extremely limited (most studies were small and short-lived), what they did gather indicates that eating more frequently has no positive effect on weight loss or weight maintenance.

Perhaps its time we let this one go?

Why is celiac disease getting more common?

A new study suggests that celiac disease is four times more common today than it was even fifty years ago. That's an extraordinary finding. And lest we think that this is simply due to an uptick in awareness and diagnosis, the researchers disproved this with a very interesting approach.  They tested stored blood samples taken from American soldiers in the 1950s. Only one in every 700 samples contained the antibody that signals celiac disease. Today, about one in 170 people test positive for the antibody.

Celiac is caused by an intolerance to gluten, a protein found in wheat and other cereal grains.  When challenged with gluten, the body's immune system attacks the cells lining the small intestine causing digestive chaos and nutrient malabsorption. It's treated by strict avoidance of gluten-containing products.

Possible explanations

Scientists are stumped.  But it strikes me that we might consume a lot more gluten today then they did in the 50s. As anyone trying to avoid gluten can tell you, gluten is in virtually every type of processed food and our diet has become increasingly dominated by processed foods.  Perhaps over-exposure to this protein increases the chance of developing an intolerance?

Other possible explanations include environmental and lifestyle changes.  As people spend more time indoors (and slather themselves with sunscreen when they go out), vitamin D deficiency has been on the rise, and has been linked with other auto-immune conditions, particularly multiple sclerosis.

Perhaps widespread use of over-the-counter and prescription acid-blockers (unavailable in the 50s) plays a role in this digestive disorder. All that stomach acid we're suppressing normally helps break down proteins. Incompletely digested proteins could be more likely to provoke an immune reaction, especially if they "leak" into the blood stream from the large intestine.

Perhaps a decrease in our consumption of naturally-fermented foods with beneficial bacteria plays a role? Beneficial bacteria help maintain the integrity of the intestinal lining and prevent large molecules (such as intact proteins) from being absorbed into the bloodstream.

It doesn't seem like a stretch to imagine that the increase in refined sugar consumption could be related.  A high sugar diet can affect the intestinal flora and function.

Obviously, there are a lot of paths for future inquiry. I don't expect definitive answers anytime soon.

Avoiding gluten has gotten easier

 The good news is that manufacturers are responding to the growing demand for gluten free products. Avoiding gluten has become fashionable among people without celiac disease as well. A return to unprocessed, whole foods can also make gluten avoidance easier--no mysterious ingredients, no hidden gluten.

Resources

More information on celiac disease

Resources for gluten-free living

Gluten-free foods

Feel free to post other resources below.

Soy sauce may help you reduce salt despite its high sodium levels

If you're watching your sodium intake,  you probably steer well clear of soy sauce. A single tablespoon contains 1,000mg of sodium.  But it looks as if the sodium in soy sauce may go a lot further when it comes to seasoning your food.

Researchers found that when they used soy sauce instead of salt in various dishes, they could reduce the total sodium content by up to 50% without tasters even noticing.  The researchers theorize that the more complex flavor and odor profile of soy sauce creates the sensation of saltiness and savour with less sodium.

Interesting, huh? Try it yourself and see what you find.  I suggest that you measure any soy sauce you add to food or recipes, at least at first, so you can compare the amount of sodium to what you'd ordinarily add from salt. As a bonus, soy is fermented to make soy sauce and this is thought to be the healthiest way to consume soy. The fermentation decreases phytates and oxalates that may impair the absorption of nutrients.

Soy sauce probably wouldn't make a good substitute for salt in baked goods like muffins or cookies.  But I could see it being a tasty addition to low-sodium tomato juice, soups, casseroles, and eggs, in addition to the obvious stir-fries.

Calorie counts on menus shockingly inaccurate

A few weeks ago, I posted on the growing trend requiring restaurants to post calorie counts on the menus. Judging from the dozens of comments, a majority of you think this helps you (and others) make healthier choices--although a notable minority disagree.

But how helpful is it if the menu disclosures underestimate the actual calories by 30 to 40%?

Check out the results of a recent spot-check conducted by Scripps, as represented in this photograph that accompanies a story in the Wall Street Journal:

 

The restaurants argue that some variation is inevitable--which of course it is. But these margins of error are enough to render the entire exercise somewhat meaningless, wouldn't you agree?

Read more about the foibles and fall-out of restaurant calorie disclosure in Carl Bialik's Wall Street Journal article..

Not all trans fats are man-made

Q. Your website states that certain meats contain trans fat. I was under the impression that trans fat is man-made and occurs only in things like hydrogenated & partially hydrogenated oils, not natural foods. Was I wrong about that?

A. In fact, all trans fats are not man-made! As you've discovered, some unprocessed foods such as beef and dairy can also contain small amounts of trans fats. These occur naturally when one or more of the hydrogen bonds of an unsaturated fatty acid molecule get twisted. But these naturally occuring are not the trans fats that everyone is so worried about.

For one thing, research suggests that naturally occuring trans fats do not have the same damaging health effects as the man-made trans fats found in artificially hydrogenated vegetable oils. (See this article on "Natural trans fats" for more details on the research.) Secondly, the amount of natural trans fats that we get from meat and dairy products is quite minor compared to the amount of man-made trans fats that we used to consume. 

I say "used to consume" because things are changing quickly on that front.  Due to a combination of legislation and consumer pressure, artificially hydrogenated oils are slowly disappearing from our food supply.  Manufacturers of processed foods, such as chips, snacks, baked goods, baking mixes, cereals, salad dressings, and sauces are removing all or most of the trans fats from their products.  Several fast food restaurants have reduced or eliminated trans fats in their French fries, fried chicken, and other foods. And many cities have enacted or are considering trans fat bans for all restaurants.  Hopefully, we'll one day reap the benefits of these changes in the form of lower rates of heart disease.

You don't need to be concerned with small amounts of trans fats in beef or dairy products. Naturally occuring trans fats are almost always exempt from labeling rules and other anti-trans-fat initiatives. 

Protect your skin without blocking vitamin D production

July is UV Safety Month, an opportunity to remind everyone that using sunscreen will reduce your risk of skin cancer and prevent premature skin aging.  As with so many things, however, it may be possible to overdo it with the suncreeen. A limited amount of sun exposure (without sunscreen) may help to prevent vitamin D deficiency. See also this related post: Sunscreen, Vitamin D, and Cancer.

Eating certain foods can help protect your skin from the inside without interfering with vitamin D production in the skin. A combination of responsible sun exposure, an antioxidant-rich diet, and appropriate use of sunscreen may be the best of all worlds.

Foods that prevent and repair UV damage

Vitamins C and E are particularly effective in preventing and repairing ultraviolet damage to the skin.  Eating foods rich in these nutrients has actually been shown to help prevent or lessen the extent of a sunburn!

Here's the tricky part: These vitamins are much more effective together than either is by itself, but there aren't many foods that are high in both nutrients. Foods high in vitamin C include red and green bell peppers, guava, kale, parsley, collard greens, turnips, and broccoli.  Vitamin E is found in wheat germ oil, sunflower seeds, safflower and sunflower oils, almonds, and avocados.

To give your skin maximum protection, you'll need to combine foods from both groups.  Guacamole with fresh red and green pepper strips would make a delicious, skin-loving snack! Try this guacamole recipe from Epicurious.com. Or, how about a crisp broccoli salad topped with slivered almonds? Here's my own personal recipe.   

These foods help nourish and protect your skin, but remember to wear your sunscreen if you will be out in the sun for an extended period of time.