Chocolate: Health Food or Not?

At this time of year, perhaps you've finished off your Valentine's Day chocolate, only to be looking forward to some chocolate in your Easter basket soon.  Americans definitely need to cut down on sweets:  The high sugar and saturated fat content in most milk chocolate can be a contributor to obesity and metabolic syndrome (a combination of insulin resistance, high blood pressure, and abnormal blood lipid levels).

On the other hand, the evidence for the health benefits of chocolate have been accumulating more and more in recent years.  The perks seem to be related to the flavanol content of the cocoa bean (Theobroma cacao).  The higher the cocoa (cacao) content, the better:  and dark chocolate (55% cacao or higher) is your best bet.  Eating an average of about one ounce per day can really boost cardiovascular and general health, including:

• Decreasing stroke risk by 14% for women (1) or 17% for men (2)
• Decreasing risk of heart failure in older women by 26-32% (3)
• Modestly reducing blood pressure (4-7)
• Decreasing "bad" cholesterol (LDL), and increasing "good" cholesterol (HDL) (8-9)
• Improving cognitive function (10)
• Most surprising of all:  decreasing body mass index (BMI) (11).  In other words, chocolate can lead to weight loss!

Just remember to enjoy your dark chocolate in moderation, as part of an overall nutrient-dense Mediterranean-type diet, including lots of fruits and veggies, nuts, legumes, lean protein, and healthy fats such as extra virgin olive oil.

1. Larsson SC, Virtmo J, Wolk A. Chocolate consumption and risk of stroke in women. J Am Coll Cardiol. 2011;58:1828-1829.
2. Larsson SC, Virtamo J, Wolk A. Chocolate consumption and risk of stroke: a prospective cohort of men and meta-analysis. Neurology. 2012;79:1223-1229.
3. Mostofsky E, Levitan EB, Wolk A, Mittleman MA. Chocolate intake and incidence of heart failure: a population-based prospective study of middle-aged and elderly women. Circ Heart Fail. 2010;3:612-616.
4. Ried K, Sullivan TR, Fakler P, Franks OR, Stocks NP. Effect of cocoa on blood pressure. Cochrane Database Syst Rev. 2012;8:CD008893.
5. Buijsse B, Weikert C, Drogan D, Bergmann M, Boeing H. Chocolate consumption in relation to blood pressure and risk of cardiovascular disease in German adults. Eur Heart J. 2010;31:1616-1623.
6. Taubert D, Roesen R, Lehmann C, Jung N, Schömig E. Effects of low habitual cocoa intake on blood pressure and bioactive nitric oxide: a randomized controlled trial. JAMA. 2007;298:49-60.
7. Buijsse B, Feskens EJ, Kok FJ, Kromhout D. Cocoa intake, blood pressure, and cardiovascular mortality: the Zutphen Elderly Study. Arch Intern Med. 2006;166:411-417.
8. Jia L, Liu X, Bai YY, et al. Short-term effect of cocoa product consumption on lipid profile: a meta-analysis of randomized controlled trials. Am J Clin Nutr. 2010;92:218-225.
9. Mursu J, Voutilainen S, Nurmi T, et al. Dark chocolate consumption increases HDL cholesterol concentration and chocolate fatty acids may inhibit lipid peroxidation in healthy humans. Free Radic Biol Med. 2004;37:1351-1359.
10. Desideri G, Kwik-Uribe C, Grassi D, et al. Benefits in cognitive function, blood pressure, and insulin resistance through cocoa flavanol consumption in elderly subjects with mild cognitive impairment: the Cocoa, Cognition, and Aging (CoCoA) study. Hypertension. 2012;60:794-801.
11. Golomb BA, Koperski S, White HL. Association between more frequent chocolate consumption and lower body mass index. Arch Intern Med. 2012;172:519-521.

Good Bacteria = Smaller Waistline?

Research in the area of normal flora -- the "good," or beneficial bacteria that live in our gut -- has been exploding in recent years.  It has been known for a long time that supplementing with probiotics (those friendly bacteria like Lactobacillus and Bifidus) can help with conditions ranging from eczema to allergies to irritable bowel syndrome.  But the list of benefits of proper microbial balance keeps growing -- and it seems like the more we know, the more we realize how much we don't know yet.

Recently, Chinese researchers (1) found a connection between the microbes in our gut and the problem of obesity.  Mice that were bred to be resistant to obesity, in spite of a high-fat diet, rapidly gained weight when injected with a bacteria from the human gut called Enterobacter cloacae.  They hypothesize that a harmful substance produced by these bacteria, called endotoxin, contributes to insulin resistance.  Insulin resistance is a major contributor to overeating and obesity, and the hallmark of type 2 diabetes.  Think of insulin as a key to open the door to your cells so they can take in blood sugar for energy; insulin resistance is where the lock on the cell doors gets worn and rusty, making it more difficult for insulin to do its job.  Insulin levels rise, which contributes to widespread inflammation in the cardiovascular system, and promotes fat storage.

In the same article, the researchers report a case study of a man who lost 66 pounds in 9 weeks by switching to a diet that promoted good bacteria growth in the intestinal tract.  The harmful Enterobacter was reduced to undetectable levels.

Now before you pop an acidophilus supplement or grab a Yoplait, expecting miraculous weight loss, we need to look a little more closely at the diet supplied to this test subject.  It was very high in fiber, to feed the good bacteria in the gut, and also included traditional Chinese fermented foods that might seem challenging to our palates.  Fermented foods are beginning to look more important than probiotic supplements, simply because of sheer numbers:  supplements might have anywhere from 1 billion to 20 billion bacteria per serving, which sounds like a lot, until you realize that there are about 100 trillion bacteria in your gut!  Traditional fermented foods have much higher levels of good bacteria than supplements.  We're not talking about most commercial yogurts, which are crammed with sugar and have questionable amounts of active bacterial cultures; we're talking about plain yogurt, kefir, miso, traditional sauerkraut, and kimchi, to name a few.

We've barely scratched the surface on research into our normal flora -- not just in the gastrointestinal tract, but also on the skin, respiratory tract, and genitourinary tract.  It makes sense that they would have such a huge influence on our health:  there are ten times as many bacterial cells as human cells in our bodies!  We are really more of an ecosystem rather than a single organism.  Perhaps in the future there will be much less emphasis on therapeutic nutrition, except as it applies to how it influences our flora.

1.  An opportunistic pathogen isolated from the gut of an obese human causes obesity in germfree mice.  The ISME Journal advance online publication 13 December 2012; doi: 10.1038/ismej.2012.153

To Calcium or Not to Calcium?

Two big studies that came out recently have muddied the waters on the one nutritional supplement that even conventional medicine has rallied behind:  calcium.

We've all heard that supplemental calcium is good for the bones, and may even protect against colon cancer in older adults.  Seems like a logical recommendation.  But like hormone replacement therapy, whose cardiovascular benefits were disproven ten years ago by the Women's Health Initiative study, calcium supplements are now being called into question.

The first chink in the armor came a few weeks ago when a study sponsored by the National Institutes of Health (NIH) (1) found that supplemental calcium boosts the risk of death by cardiovascular disease (CVD) in men, but not women.  Men who consumed 1000 mg/day of calcium supplement had a 20% higher risk of CVD death than those who took no calcium.

OK, great... men, ditch the calcium; women, keep popping those ginormous horse pills.  Until February 13, when BMJ (British Medical Journal) (2) published the findings of Swedish scientists, who found that calcium supplements increased death rates in women, too.  Examining the findings more closely, though, we find some important details:  the all-cause mortality rates were doubled in women with a calcium intake of  more than 1400 mg/day, compared to those getting 600-1000 mg/day.  A further complication is that risk of death was increased if the calcium came from supplements rather than food.

The US Preventive Services Task Force (3) has also chimed in, with a re-analysis of older data that showed that 400 IU of vitamin D plus 1000 mg of calcium per day did not significantly prevent fractures in healthy older women.

These studies add more weight to hints that have been accumulating over the years, that just increasing calcium intake is not necessarily better for health.  Some cultures of the world have very low levels of calcium intake, but very little osteoporosis.  Meanwhile, the US recommendations for daily calcium have climbed over the years, so that now the RDA for women over age 50 is 1200 mg/day.  When it comes to bone health, just adding more calcium is like throwing more bricks on a construction site, and hoping that they'll form a building.  You also need an architect and foreman -- namely, vitamin D and vitamin K.

So how do we parse all this confusion about calcium, health, and disease for older adults?  Here's my bottom line:

• Men:  Keep your daily calcium intake under 1000 mg/day.  For most men, this means skipping the calcium supplements altogether.
• Women:  Ditch the high-dose calcium supplements that provide 1000-1500 mg/day.  Aim for that 600-1000 mg/day range total between dietary and supplemental calcium, with an emphasis on dietary sources (dairy, leafy greens, sardines).
• Men and women:  Get your blood tested for 25-hydroxyvitamin D on a regular basis; aim for a level between 40-80 ng/ml.  If it is low, you may safely take higher levels of supplemental vitamin D3 (consult your doctor for the right amount -- I usually recommend anywhere from 2,000-10,000 IU per day).  If you have CVD, osteoporosis, or risk factors for these conditions, be sure to get extra vitamin K along with vitamin D3.

Stay tuned; like all of nutritional science, the landscape and recommendations are constantly in flux.

1.  Xiao Q, Murphy RA, Houston DK, Harris TB, Chow WH, Park Y. Dietary and supplemental calcium intake and cardiovascular disease mortality. JAMA Intern Med 2013; DOI:10.1001/jamainternmed.2013.3283. 

2.  Long term calcium intake and rates of all cause and cardiovascular mortality: community based prospective longitudinal cohort study.  BMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f228 (Published 13 February 2013)

3.  

Vitamin D and Calcium Supplementation to Prevent Fractures in Adults: U.S. Preventive Services Task Force Recommendation Statement.  Ann Intern Med. 26 February 2013

Another Nail in the Coffin for Diet Soda

All right, Dr. Peters, will you lay off the diet-soda-bashing melodrama?

No.  The answer is no.

You've read my articles before about how diet soda actually promotes weight gain rather than weight loss, and more seriously, raises the risk of stroke significantly.  Is that Diet Coke fix worth a brain attack that could lead to permanent neurologic deficit, or even death?

Now French researchers have published findings (1) that consumption of lots of diet soda more than doubles the risk of developing type 2 diabetes, compared to non-soda drinkers.  This is an even higher risk than regular soda drinkers!  As you know, type 2 diabetes is like aging on fast forward, accelerating the development of cardiovascular disease, nerve problems, kidney disease, eye problems, and other complications.  But wait -- how much is "a lot" of diet soda?  More than about 600 ml per week.  Or for us Americans, about 20 fluid ounces.  Yes, just one 20 oz. bottle per week.  Know anyone who drinks more pop than that?

So let's look at the arguments of the beverage industry:

• "Diet soda is a good choice for those trying to lose weight, since it contains zero calories."  FALSE
• "Diet soda is a good choice for diabetics, since it contains no sugar."  FALSE

Consider the alternatives:

• Get a reusable water bottle, and make pure water your go-to drink.  Add a squirt of real lemon or lime juice for a little flavor, if you miss it.  No need to replace one highly processed food (diet soda) with another ("designer" waters).
• Green tea:  go beyond the Lipton -- there are many different varieties, with flavors that should appeal to everyone.  And how about a 20-30% lower risk of cardiovascular disease as a bonus?

1.  Consumption of artificially and sugar-sweetened beverages and incident type 2 diabetes in the Etude Epidémiologique auprès des femmes de la Mutuelle Générale de l'Education Nationale–European Prospective Investigation into Cancer and Nutrition cohort.  January 30, 2013, doi: 10.3945/​ajcn.112.050997.  Am J Clin Nutr March 2013 ajcn.050997

What's Wrong with a Little Snack?

...Nothing, as long as it does not turn into a big snack.

One of the major factors that has been consistently found to influence weight gain or loss is controlling portion size.  Sometimes this is easier said than done -- for example, at buffets where the available portions are seemingly endless.

Researchers at Cornell University (1) recently ran an experiment to test this in a new way.  They gave two groups of people different serving sizes of snack foods (chocolate, pie, and potato chips) -- either small or large portions.  Of course, the choice of foods was not ideal (unless you count the health benefits recently coming to light for chocolate), but the point of the study was to look at calorie intake.  Not surprisingly, the small serving group took in fewer calories -- an average of 100 fewer.  What was important, though, is that they found no difference in reported satisfaction between the two groups.

This highlights a major principle of our food consumption:  the difference between hunger and appetite.  Hunger is the physiological need for food, detected and driven by the hypothalamus in the brain.  Appetite is the psychological desire for food, which can be the result of numerous factors -- one of which might be how much we have available in front of us.

So if you're going to have a snack, remember these principles:

• Measure out a small serving of snack ahead of time.  Don't grab the whole bag.
• Eat slowly -- give your brain a chance to catch on to that feeling of a satisfied appetite before reaching for more.

1.  Van Kleef, Ellen, Mitsuru Shimizu and Brian Wansink (2013). Just a bite: Considerably smaller snack portions satisfy delayed hunger and craving, Food Quality and Preference, 27(1):96-100

Exercise for Weight Loss: Take a Hint from Goldilocks

This is the time of year when many folks' New Year's resolutions include shedding a few (or a lot) of those excess pounds.  A healthy, balanced diet with proper portion control is the place to start, of course.  And starting an exercise program has tremendous health benefits, even beyond the waistline.  New research suggests, though, that more is not necessarily better -- even with something as healthy as physical activity.

Researchers at the University of Copenhagen in Denmark (1) explored the question of the effect of amount of exercise on weight loss.  They looked at overweight sedentary men, dividing them into three groups:

• a control group (no exercise)
• moderate exercise (300 calories burned per day, or about 30 minutes of running or cycling)
• high exercise (600 calories burned, or about 60 minutes per day)

After 13 weeks, they examined weight loss in the three groups.  Not surprisingly, the control group showed no change in weight.  The high-exercise group lost an average of about five pounds -- respectable, but actually less than expected, given the number of calories these gentlemen were burning.  But the moderate exercisers actually lost more weight:  about seven pounds on average, or forty percent more than the high-exercise group!  What could account for this Goldilocks effect -- not too much, not too little, but just right?

There is one major factor that the researchers did not examine:  body composition.  In other words, how much muscle and fat did each subject have at the beginning and end of the study?  The high exercisers were probably gaining more muscle than the moderate group, resulting in a lower net weight loss.  For this reason, I like to measure body composition (via bioimpedance analysis) at my clinic to more accurately track changes over time.  Lead scientist Mads Rosenkilde admits that if the study extended beyond 13 weeks, the metabolic benefit of increased muscle mass might become more noticeable in the high exercisers.

Nevertheless, there are at least two major pitfalls that the researchers identified for the high-exercise group.  The increase in calories burned seemed to lead to a compensatory increase in food intake -- this was most likely unconscious, a result of altered hormonal control over hunger signals (the set point theory).  A unique aspect of this study is that the subjects were equipped with motion sensors, to record their physical activity outside of the formal exercise periods.  The high exercisers were actually more sedentary the rest of the day compared to the moderate group -- perhaps due to fatigue, or perhaps they just felt they "deserved" more rest.

This study gives us plenty of food for thought on physical activity.  But like everything, let's take it in the context of all research, not just the latest headline:

• Any exercise is better than none at all.
• If you are using a lower intensity exercise such as walking, it might take 45-60 minutes to hit that 300 calorie burn goal.
• Short bursts of high-intensity exercise have been shown to have greater metabolic benefit overall than prolonged sessions of more moderate intensity exercise:  The improvement in insulin sensitivity can lead to better weight management with as little as 60 minutes per week. (2)

1.  Body fat loss and compensatory mechanisms in response to different doses of aerobic exercise--a randomized controlled trial in overweight sedentary males.  Am J Physiol Regul Integr Comp Physiol. 2012 Sep 15;303(6):R571-9. doi: 10.1152/ajpregu.00141.2012. Epub 2012 Aug 1.

2.  Just HIT it! A time-efficient exercise strategy to improve muscle insulin sensitivity.  J Physiol. 2010 September 15; 588(Pt 18): 3341–3342.

Seeds of Heart Health for the New Year

You've probably heard my mantra for a healthy diet (borrowed from author Michael Pollan):  "Eat food.  Not too much.  Mostly plants."  To expand on this, we can look to the Mediterranean diet -- that style of eating that is based on whole grains, vegetables, nuts, legumes (beans), and smaller amounts of animal-based protein.  This simple approach works well for maintaining a healthy body weight, and preventing chronic diseases such as cardiovascular disease.

A review (1) in the journal Clinical Lipidology (yes, you read that right; "lipidology" means the study of cholesterol and other fats) looks at dietary factors most associated with lowering cholesterol.

"The foods with the most evidence for cholesterol reduction are nuts, legumes, whole cereals rich in soluble fiber, and cocoa and its main commercial product, chocolate."

OK -- this sounds a lot like the Mediterranean diet.  What the author goes on to point out, though, is that all of these foods are actually seeds.  Obvious once someone points it out, isn't it?  Yet with as many years as I've taught patients and students about nutrition, this struck me as a beautifully concise revelation.  Even whole grains like oats are seeds.  And chocolate?  Yes, please!

Seeds contain fiber, healthy fats, and disease-busting phytonutrients.  Think of them as plant foods bursting with concentrated potential.

1.  Ros E.  How Important Is Dietary Management in Hypercholesterolemia?  Clin Lipidology. 2012;7(5):489-492.