So, CRP doesn't cause heart disease. I never thought it did.

Much has been made this week about some new studies showing that C-reactive protein, a compound that signals systemic inflammation, does not cause heart disease. See this description of the research from CNN (Study suggests C-reactive protein doesn't cause heart disease) and this reaction from the LA TImes: If C-Reactive protein isn't a cause of heart disease, what is?

Frankly, I'm not sure what the fuss is all about.  The media is acting as if the link between inflammation and heart disease has been thrown into question. It hasn't.

C-reactive protein is one of several markers for systemic inflammation. Elevated CRP levels indicate an increased risk for heart disease--and many other diseases as well.  While I guess it was important to make sure one way or the other, I, for one, never thought that CRP itself caused heart disease or arterial damage. It simply signals that inflammation is present.

A Declaration of Independence?

Many have questioned whether CRP is an independent risk factor. In other words, does measuring CRP levels really tell us anything that we don't already know from other screening tests?

I think it does. The other gold standard for assessing heart disease risk (cholesterol) is notoriously flawed.  Measuring both CRP and cholesterol gives a more complete and nuanced picture.  Monitoring CRP can also be a valuable way to monitor the effectiveness of treatment, especially lifestyle and diet interventions.

CRP screening is relatively inexpensive (around $60) and no more invasive than a standard cholesterol test. Plus, as this recent study points out, elevated CRP levels can help identify who is at highest risk for fatal (as opposed to non-fatal) heart attacks and might help us pinpoint those who would benefit from more aggressive treatment regimens.

Tell me something I don't know

For me the big unanswered question about CRP and disease risk is not whether the protein itself causes damage (which it apparently does not). What I'm waiting with bated breath to see is whether lowering elevated CRP with diet and lifestyle (as opposed to pharmaceuticals such as statin drugs) lowers the risk of disease.

Soy isn't affecting men's hormone levels...but something is

A new analysis seems to put to rest concerns that eating too much soy could affect testosterone levels in men.  Soy contains weak plant estrogens and many have worried that the increasing popularity of soy products (and the ubiquitous use of soy-based additives and ingredients) could be de-masculinizing our men.

After analyzing the pooled results of 15 different studies, including two which concluded that soy DID affect testosterone levels, researchers say "No significant effects of soy protein or isoflavone intake on testosterone or SHBG [sex hormone-binding globulin] were detected."

Perhaps we were focused on the wrong culprit.

In an opinion piece for the New York Times on Sunday, Nicholas Kristoff warns that endocrine disruptors widely used in agriculture and industry are being linked to "evidence of increasing abnormalities among humans, particularly large increases in numbers of genital deformities among newborn boys."

Kristoff cites a statement released by the Endocrine Society as a "wake-up call."  According to the paper, endocrine disruptors are affecting both men and women, causing reproductive problems, deformities, cancer, and may even be related to rising obesity rates.

You can avoid soy. You can eat only organic produce. Yet these chemicals are so widely used and so poorly contained that, as Kristoff notes, "everyone is exposed."

The chemical companies are crying foul, claiming that it's all unproven conjecture. What do you think? Should the chemicals be presumed innocent until proven guilty? Or have we seen enough to take action to limit the use of these chemicals?

New devices measure your metabolism, but how accurate are they?

To maintain your weight, you need to match your calorie intake to your calorie usage. And if you're trying to lose weight, you need to make sure that you consistently take in fewer calories than you are using.

Most people simply estimate how many calories they can afford using tools such as our Daily Needs Calculator. But there are a bunch of new gadgets on the market that claim to give you an exact read on how many calories you're burning. 

Just how accurate are they? Perhaps less precise than you might think The type of devices that are worn next to the skin--costing anywhere from $50 to $200--can be off by anywhere from 10% to 30%.   If you're willing to fork out significantly more ($7000 to $10,000), you can buy a device that measures your resting metabolism when you breathe into a mask for several minutes. These calorimeters can reveal individual differences in basic metabolic rate but can't tell you how many calories you are burning through exercise and other activities.

Here are links to reviews of some of the latest gadgets:

Find out how many calories your body burns (Chicago Tribune)
How accurate are devices that track calories? (Wall Street Journal)

Or, you can keep doing it the low-tech, low-cost way.  Use a standard formula such as the Daily Needs Calculator to put you in the right ball-park.  Pay attention to how many calories you are actually eating. (Our tracking tools can help.) Adjust as necessary.  If you're maintaining your weight, you've found your calorie balance. To lose weight, cut back on your intake or step up your output.

Are BMI guidelines for the birds?

Q. I recently read that the standard BMI calculation and guidelines aren't accurate for African-Americans and other ethniticies. Can you explain why and do you have recommendations for ethnic specific guidelines?

A. Your BMI, or body mass index, is nothing more than a way of expressing your weight in relation to your height.  When we say that a BMI of between 19 and 25 is considered ideal, we're really just saying that for every height, there is a suggested healthy weight range. I'm 5'9" for example.  The suggested healthy weight range for me is 128 to 169.  (Click here to look up your BMI)

I think you're probably referring to a recent article in the British Journal of Nutrition  (reported in the Washington Post), which points out that the BMI guidelines are based on statistics gathered in a predominantly Caucasian population.  

Because of differences in average bone density, lean muscle mass, and so on, the BMI guidelines may be misleading for non-Caucasians. For example, it might underestimate healthy weight range for some people of African descent and overestimate the range for some of Asian descent.  Even for Caucasians, though, the BMI is a fairly crude gauge of body composition. For example, it's not a good guide for athletes, who have more muscle mass, or for the elderly, who have lost muscle and bone mass.

The BMI guidelines are supposed is to help identify people who may have too much (or too little) body fat.  Other ways to gauge whether you are carrying around an unhealthy amount of fat include:

Have a fitness trainer measure your body fat percentage.  The recommended percentage depends on your age and gender but as a very general guideline, women should try to keep body fat under 30% and men under 25%.  There are several methods of measuring body fat. The most accurate is also the least convenient: It involves being submerged in a tank of water.  A fitness trainer can get a pretty good estimate using body fat calipers--but good training and technique are essential.  Those scales and hand-held devices that calculate body fat by measuring electrical impedance are notoriously inaccurate.

Measure your waist size. A waist measurement of more than 35" for women or 40" for men increases your risk of heart disease and other diseases.

Calculate your waist-to-height ratio by dividing your waist measurement by your height.   If you are 5'5" and your waist measures 32", your ratio would be 32/65 or 0.49.  A ratio of less than 0.50 is considered healthy.

Calculate your waist-to-hip ratio by dividing your waist measurement by your hip measurement.  If your waist measures 32" and your hips measure 38", your ratio would be 32/38 or 0.84.   As a general rule, women are shooting for a ratio of less than 0.8 and guys for a ratio of 0.95 or less.

Ask your physician for individual guidance.  Your physician sees the whole you, not just a single measurement or statistic. If you're not sure whether your weight is healthy or not, ask your health care provider for input.

Manufacturers replacing high fructose corn syrup with sugar. Big deal.

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 overconsume 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.

Regular versus instant oatmeal

Q. I have been eating instant oatmeal almost daily for a couple of years now. A friend recently told me I have been wasting my time if I thought I was eating it for nutritional reasons. Is instant oatmeal less effective than the regular stuff?

A. Actually, the nutritional differences between regular and instant or quick-cooking oatmeal are so insignificant that the Nutrient Data Laboratory for the USDA has just one analysis which applies to all three kinds of oatmeal.  All three contain the same amount of fiber and the same amount of cholesterol-lowering compounds.

The biggest difference is in taste and texture.  Regular oatmeal contains larger pieces of rolled oat grains and is a little chewier than the instant and quick-cooking varieties. (Ironically, it really doesn't take much longer to cook regular oatmeal than it does to make instant.)

Of course, I'm only talking about plain oatmeal. If the instant oatmeal that you're eating is flavored, then you're also getting a big helping of sugar with your oats. While that doesn't take anything away from the oatmeal, it may add undesirable (empty) calories. Also the little packets of instant oatmeal usually contain a slightly smaller serving than the standard serving of regular oatmeal--so you're getting a slightly smaller helping of fiber.

But rest assured that a serving of plain instant oatmeal is just as nutritious as the same amount of plain regular oatmeal.

Being a carb-counting vegan is a tough job

Q. I'm attempting to maintain a 40-40-20 macronutrient balance with the assistance of your website's tools.  As a vegan athlete, I eat more vegetables and grains than an omnivore, and it is nearly impossible to achieve the 40-40-20 balance without cutting down on either vegetables or carbs, which I believe would not be healthy for me. Is there a way for the caloric ratio pyramid tool to take into account the difference between vegetable carbs and cereal/grain carbs?

A. Not really--but I'm not sure how that would help.  The Caloric Ratio Pyramid shows you how your calories are divided between carbohydrates, protein, and fat but doesn't distinguish between different sources of these macronutrients.  So, your carbohydrate percentage will include the carbohydrates you get from grains, vegetables, dairy products and fruits.

But here's the thing: Although vegetables are almost 100% carbohydrate, most are still very low in carbohydrates. So cutting down on vegetables isn't going to change your macronutrient distribution nearly as quickly as cutting down on grains.  A one cup serving of brown rice, for example, contains 216 calories and 45 grams of carbs. If you are eating 2100 calories a day, that would be 10% of your calories, right there.

A salad made with SIX CUPS of raw spinach, on the other hand, contains just 42 calories and 6 grams of carbs (or about 2% of your 2100 calorie diet).  So, I'm not sure it makes much sense to try to the adjust the carbohydrates proportion of your diet by cutting back on vegetables.

You're absolutely right: Vegans usually end up consuming a diet that's higher in carbohydrates and lower in protein than omnivores. After all, some of the most common vegan protein sources--legumes--contain about as much carbohydrates as protein. Nonetheless, it's possible for a vegan to eat a lower carb/higher protein diet. Tough, but possible. (Whether or not its necessary or desirable is a subject for another post).

ND Tools for customizing your diet

Here on ND, you might want to start by setting your preferences so that results from meat, dairy, and egg categories don't show up in your searches. Then, try a search with our Nutrient Search Tool for foods high in protein and low in carbohydrates. Click on the various categories to refine your searches.

Or, use our super-cool Caloric Ratio Search tool!

 

Position your cursor on the pyramid to select a certain macronutrient ratio and click to see a list of foods that match that ratio. Keep in mind that in a 40/40/20 diet, very few individual foods are likely to be 40/40/20.  But say your typical mealplan always seems to lean too heavy on the carbs and fat and too light on the protein. Put your cursor on the part of the pyramid that's high in protein and low in carbs and fat and click for a list of foods that can help you balance your diet.

Calling all low-carb and athlete vegans:

Seems to me we've had some low-carb vegans commenting on this blog in the past and I know we have some vegan body-builders. Anyone out there want to share some more strategies or resources?

How much protein for a healthy pregancy?

Q. My protein is limited to chicken, fish, eggs. Is there a safe protein shake supplement I can take whilst pregnant ? And how many calories daily should I be consuming ?  I'm 36 years old and weigh 80kg.

A. How many calories you need really depends on your pre-pregnancy weight.  The guidelines for weight gain during pregnancy were just revised because so many women are beginning their pregnancies overweight.

You didn't mention how tall (or pregnant) you are, but if you're of average height (5'4") and your weight was close to 80kg (176lb) before you got pregnant, your pre-pregnancy BMI would have been around 30. According to the new guidelines, you should gain no more than 11 to 20 pounds during your entire pregnancy--and the lion's share of that should be during your 3rd trimester. (Click here to read more about the new guidelines.)  

Because a higher BMI puts you in a higher risk category, I'd strongly recommend that you check with your doctor to get more specific guidance about how much weight you should be gaining and how many calories you should be eating throughout your pregnancy.

In terms of protein, the Institute of Medicine suggests that you get at least 1 g of protein per kg of body weight during pregnancy. So, in your case, at least 80g per day now and 91 to 100 g a day by the end of your pregnancy. Chicken, fish, and eggs are all great source of protein and it may be that you are getting all the protein you need without a protein supplement.   You can use our tools to see how much protein you are consuming from these foods.

If you do decide to use a protein supplement, I'd steer clear of ones with a lot of added vitamins, as you're probably taking a high dose prenatal vitamin already. Look for for one that's very simple and doesn't contain any artificial sweeteners, herbal ingredients, or caffeine.  Again, your obstetrician is there to give you personalized guidance about all aspects of your pregancy, including diet and nutrition!

Healthy Weight Loss: When the usual formulas don't apply

Q. I want to lose 10-15 pounds, which would put me in the middle of the healthy weight range for my height. I've read that losing 1-2 pounds a week is healthy.  However, when I used the daily needs calculator on your site, it said if I cut back to the recommended minimum of 1200 calories per day I could only lose .4 pounds a week.  So which is right?  Could exercise help explain the discrepancy?  Thanks!

Q. It sounds as if the daily needs calculator estimates that it takes about 1400 calories to maintain your current weight. In order to lose one pound a week, you'd have to cut back to about 900 calories per day--and that's lower than we usually recommend that you go for more than a day or two because it increases the chances that you'll be falling short on important nutrients.

If you cut back to the recommended minimum of 1200 calories/day, you'll only be creating a 200 calorie per day deficit, which adds up to the slower  .4 lb/wk weight loss.

Remember, though, that these guidelines are rules-of-thumb, designed for the average-sized person. Most people burn something closer to 1600 to 2400 calories per day. So if they cut back to 1200 calories, they create a much bigger deficit and lose the weight a lot faster. That's what the 1-2 pound/wk estimates that you see are based on.

But 1400 calories is pretty low--suggesting that you're either rather small, somewhat older, and/or fairly sedentary.  Losing a half-pound a week might be a perfectly  appropriate pace for you, especially if you are on the smaller side and this half pound represents a larger percentage of your total weight.

A nutritionist or dietician would be able to give you more personalized guidance about appropriate calorie intake for weight loss.  But you're on to something:  burning more calories with exercise will create a bigger deficit (without you having to dip below 1200 calories) and speed your weight loss.

Related content: 
How many calories do I need?
Diet and Weight Loss Resource Center

Understanding the difference between dietary cholesterol and blood cholesterol

Q. Here in Baja, squid is abundant and we like to eat alot of it. Your site says it is high in cholesterol. Is that bad cholesterol or the good stuff? Can you break it down for me?

 

A. Dietary cholesterol (the cholesterol found in foods such as eggs and seafood) is neither "good" nor "bad."   Those terms are often used to describe different types of cholesterol-containing compounds in your blood.  In your body, cholesterol is bonded to various types of proteins to form packages called lipoproteins. LDL and HDL are two types of cholesterol-containing lipoproteins.

 

LDL is often characterized as "bad" because elevated levels are one risk factor for heart disease. HDL cholesterol is often described as "good" because high levels of this type of cholesterol lower your risk of heart disease.

 

The most recent research indicates that cholesterol from your food has very little effect on how much cholesterol is in your body.  If you're trying to reduce your LDL cholesterol, it's more effective to reduce your intake of saturated fat.

 

In other words, enjoy the squid!