Sunday, July 27, 2014

What about those Fruits and Vegetables? It depends....

I have seen more than one study challenging the utility - and even sensibility - of recommending an increase in the consumption of fruits and vegetables as a means to maintain or lose weight.  In the US, the recommendation is either just a general eat more or a more specific eat at least 5 servings.  In other countries, for example Australia, the recommendation is 2 fruits and 5 vegetables.  Walter Willett and the folks at HSPH recommend more vegetables than fruit.  

To be clear, non-starchy vegetables, specifically, and some fruits have been shown to improve health, possibly through their antioxidant properties.  But recently, using Eat More Fruits and Vegetables as an obesity prevention/treatment strategy, has come into question.  I have been concerned about the recommendation for some time, and that is why I promote Willett’s new food pyramid over the USDAs food guidance.

My concerns about fruit and vegetable promotion and all food related promotion is that people don’t hear, because its seldom said, eat more of this (x) INSTEAD of that (x).  People do not get the message that adding health promoting foods such as fruits, vegetables, whole grains, healthy oils, fish, etc. needs to be qualified.  The healthy foods are particular and only stay healthy if they remain nutrient dense (e.g., potatoes are a starchy vegetable which we do NOT need to increase, and kale is GREAT, kale cooked in fat back/butter is NOT GREAT).

Of course, fruits and vegetable calories are of a higher nutritional value than ones from chips, hotdogs and soda, but 1) the choice of fruit (e.g., a plum vs kiwi) or vegetable, 2) the preparation of that fruit or vegetable, 3) the size of that fruit or vegetable (i.e., jumbo fruits (bananas, oranges, apples = 2 or 3 servings), and 4) the overall amount of calories consumed will determine if adding fruits and vegetables to ones diet aids in weight loss.  The bulky, nutritious, fiber rich peppers, summer squash, onions and mushrooms should bulk up one's plate and reduce the caloric density of a meal– these foods should replace (or reduce) meat and pasta for instance.

Two studies released this month,(Charlton et al., 2014; Kaiser et al., 2014), found that increasing fruit and vegetable intake did not lead to weight loss and in some instances, led to weight gain.  The Kaiser et al study used robust criteria to evaluate randomized control trials (RCT) and though the RCTs themselves had limitations, the review of them was sound.  In the authors’ words, the upshot is this…. 

Purchasing and preparation barriers need to be addressed.  Interventions should provide more instruction on how to prepare vegetables in such a way as to not increase their energy content (such as not preparing vegetables with fat (eg not frying or serving with butter)… and….Although many fruits and vegetables [F/V] have demonstrable positive health benefits, recommending increased F/V consumption to treat or prevent obesity without explicitly combining with methods to reduce intake of other energy sources is unwarranted (Kaiser, et al).

One of the main reasons I started my You Tube channel was to show people how to cook foods without turning them into calorically dense meals or snacks.  So, do eat more fruits and vegetables as you eat LESS meats, breads, and desserts.

Charlton, K., Kowal, P., Soriano, M. M., Williams, S., Banks, E., Vo, K., & Byles, J. (2014). Fruit and Vegetable Intake and Body Mass Index in a Large Sample of Middle-Aged Australian Men and Women. Nutrients, 6(6), 2305-2319.

Kaiser, K. A., Brown, A. W., Brown, M. M. B., Shikany, J. M., Mattes, R. D., & Allison, D. B. (2014). Increased fruit and vegetable intake has no discernible effect on weight loss: a systematic review and meta-analysis. The American journal of clinical nutrition, 100(2), 567-576.

Thursday, July 17, 2014

Sugary Beverage Portion Cap : My View

    Recently, the NY State Court of Appeals rejected a request to reinstate the sugary beverage Portion Cap Rule proposed by former NYC Mayor Michael Bloomberg.  The court stated that the rule, which would have limited the serving size of sugary beverages* to no more than 16 ounces, would be an infringement on individual autonomy. If individuals had driven the increase in serving sizes and no evidence existed to support public health law, this would be a fair argument. 
   Economists tell us that in a properly working free market, businesses respond to demand. In this case, it would mean the beverage industry is responding to our demand (i.e., collective autonomy) for super-sized drinks. Of course, the government would be wrong to step in just because our demand made us fat especially if fatness were benign (which it’s not).  I assume that is what the Court is thinking; consumers instigated the new normal. But is that what happened?  It seems to me, and I grew up with the increase in everything, that the beverage industry decided that an 8 ounce cola with about 10 teaspoons of sugar was not sufficient a serving; the beverage industry decided that upwards of 20 ounces and 24 teaspoons of sugar was more appropriate.  You and I did not decide this. 
    Of course, people in NY have a right to as much soda as they like; this is America.  And if this were a soda ban instead of a serving size cap, I’d be one of the loudest voices against it.  It isn’t though.  The rule is an attempt to return us to pre obesity-epidemic portion sizes, sizes that changed unbeknownst and independent of us.  I feel certain no one hoped sodas would have 200 more calories. Very few of us purposefully consume extra empty calories.  So, I have to wonder whose autonomy Judge Pigott and the Court are honoring here.  
    Because I don’t think it’s Mayor Bloomberg and the NYC Board of Health who are trying to manipulate our behavior; I think it’s the beverage industry.  The mighty beverage industry pushes overconsumption and Bloomberg’s mighty brand of paternalism seems just about right to counteract it. In fact, Bloomberg and NYC have a history of doing the right thing for health.  For example, they put a price floor on a pack of cigarettes, banned smoking in restaurants, bars and parks and raised the minimum age to purchase tobacco to 21.  Maybe it is just coincidence, but New York now has one of the lowest rates of adult and youth smoking in the country.  I don’t see any reason why Bloomberg’s efforts to curtail obesity should be any less effective.
    This is how I see the Portion Cap helping.  A 24-ounce soda is a trigger to consume excess calories just like a smoking area is a trigger to smoke.  If the 24- ounce soda is off the table, the lure of value pricing and social norms cancels out and consuming the appropriate amount of calories becomes more likely, feasible and possible.  This is a great help to those who want to control their dietary intake and it does not prevent others from having as many 16-ounce sodas as they choose.
    True, I am a public health policy advocate, but I have also benefited from public health policy on a personal level. I am a former smoker and someone who has maintained a 30-pound weight loss for over 14 years.  I find that whatever makes smoking harder makes quitting easier and whatever makes calorically dense choices harder makes maintaining a health promoting weight easier.  I am not na├»ve or authoritarian; people who want to smoke will find a means to do so and people who want to drink gallons of sugar-sweetened beverages will do that too.  In America, we have a legal right to make bad choices.  But I am American, too, and I have a right to an environment which enables me to make good choices, an environment where I don’t have to fight the ‘all you can eat and drink, value sizing’ mentality.  That is my autonomy and I’ll take all the Mayor Bloomberg help I can get, thank you very much.
*a sugary beverage is one that contains 25 or more calories per 8 ounces

Tuesday, July 8, 2014

Dark Chocolate to Increase Blood Flow?

I am going to tell you about a recent study* that tested to see if chocolate, dark or milk, improved walking for persons diagnosed with PAD.  I am omitting a lot of important scientific information, but you can read the journal article here.

PAD stands for peripheral artery disease, which I have blogged about previously; a person with PAD has limited blood flow in the arteries of the lower legs because the arteries are constricted or narrow.  If you or someone you know has PAD (20% of people over the age of 70 who live in Western countries do; see citation 2 in the research publication), you are likely familiar with the term Intermittent Claudication.  During exercise or walking, a person with PAD may experience severe pain in their lower legs because of a lack of blood flow, this is Intermittent Claudication.

Intermittent Claudication limits the activity of persons with PAD and finding a way to reduce this, which means addressing the blood flow problem, is very important. Loffredo et al (physician/scientists in Italy) knew, from other studies, some of the physical, under the skin things that happen in persons with PAD (e.g., substances that act on the inner lining of the blood vessels are impaired, toxic residue from cellular actions build up because the body doesn't clean them out (oxidative stress)).  The scientists were particularly interested in the oxidative stress. Previous research had found that oxidative stress was a main reason for the constricting of the lower leg arteries, the accompanying pain and the inability to walk long or far. [there is much more to the mechanisms and I refer you to the article for a more thorough explanation]

The terms more of us may be familiar with are "free radical damage" and "antioxidants."  Antioxidants cause chemical reactions in the body, under the skin, that, in a series of interactions, can reduce the oxidative stress (caused by free radicals).  One powerful antioxidant (polyphenal type) is cocoa.  In past studies, cocoa has helped to dilate (make bigger) arteries, thus leading to improved blood flow.  If the blood flow improves, the pain should reduce and people with PAD might walk farther, longer, or both.  That is what the scientists wanted to test.  If they gave people chocolate, would their condition improve, at least for the short (immediate) term.

The Loffredo et al study was very small and considered only a proof of concept - in other words, no causation can be implied about the chocolate!  The scientists invited persons with moderate to severe PAD, who were stable, and who were not smokers, to participate.  After the initial screening, which did 'reject' 5 persons because they smoked (which is untenable to me - that they smoke when they have blood flow problems).  Only 20 people participated in the study and each person participated in both parts (i.e., crossover design) and there was no control group (another reason why it is just a proof of concept study).  I have to make an aside before I talk about the results.  

Researchers always give a little information about the sample in a study.  This allows us to see how much those people are like us, or like some larger group.  In looking at these sample characteristics, the average age was 69 and there were twice as many men as women, 90% had high cholesterol and all of them were on statin medications (among other drugs), the average BMI was 27 (overweight) and most tellingly, 80% of the people in this study were former smokers.

The scientists used several tests that diagnose and monitor PAD, including an Ankle Brachial Index and an FMD (flow-mediated arterial dilation), as well as a treadmill test, to assess the main effect (a reduction in Intermittent Claudication, increase in walking time or distance).  They collected blood and did additional tests to determine the mechanism of effect - for example, how did the chemicals in the blood (neurotransmitters and such) change after the intake of either type of chocolate and does that change explain the main effect, which is walking distance and time.  The participants were tested once after they ate dark chocolate, and weeks later, once after they ate milk chocolate, or vice versa.  (This is why it was a test of the immediate effect of chocolate consumption only.)

The upshot is that dark chocolate (dark cocoa) had a positive effect on many of the markers, including the most important one, walking; and milk chocolate did not.  The persons in the study were in bad shape to begin with, only able to walk a little more than the length of an American football field (110 meters or 120 yards).  After ingesting the dark chocolate (40 grams) the participants, on average, were able to walk 122 meters or 133 yards.  If you prefer to think of this in feet, the people increased their walking distance by 40 feet.  Also, the time that they could walk before the pain became unbearable was 124 seconds (~ 2 minutes) before the dark chocolate and 142 seconds (20 more seconds) after the dark chocolate. [Important note:  the distance and time spent walking was on a treadmill, it is possible that walking off the treadmill, inside or out, would be more difficult.]

 Some of the other measures or markers were different after the ingestion of chocolate and some were different depending on the type of chocolate.  Of importance, the FMD was different between chocolates, specifically there was more dilation after consumption of the dark chocolate.  The chemical tests showed that the dark chocolate itself had more polyphenol content than the milk chocolate and the scientists are suggesting that the antioxidant properties of the polyphenol-rich dark chocolate is responsible for the positive findings.

Yes, this is very cool.  Researchers are on the way to finding the means to moderate Intermittent Claudication so that people with PAD can be more active.  Of course, an even better thing would be to reduce the number of persons who have PAD.  Risks that we have control over include being overweight, smoking, not exercising and having high cholesterol and or diabetes. 

I noted in parentheses that the amount of chocolate the patients were given was 40 grams.  I assume this was regular chocolate and therefore would contain 200 calories.  I assure you that it takes more than 20 seconds of additional walking to burn 200 calories (more like an hour or two).

I do use dark cocoa in cookies and cakes, sweetened with sucralose; I like the taste of cocoa and when added to the antioxidants I consume in my (calorie fixed) plant based diet, I imagine it is health promoting.


*Dark Chocolate Acutely Improves Walking Autonomy in Patients With Peripheral Artery Disease

Lorenzo Loffredo, Ludovica Perri,  Elisa Catasca,  Pasquale Pignatelli,  Monica Brancorsini,
Cristina Nocella,  Elena De Falco,  Simona Bartimoccia,  Giacomo Frati,  Roberto Carnevale,
Francesco VioliJ Am Heart Assoc. 2014;3:e001072, originally published July 2, 2014, doi:10.1161/JAHA.114.001072