Latest salt Cochrane review including non-blood pressure surrogates

A new Cochrane review on dietary salt interventions was published last week by Graudal et. al (1), an update to a 2003 review. The meta-analyses examined the effects of randomized interventions with high or low dietary salt on blood pressure (BP), hormones and lipids. The trials included consisted of subjects with normal or elevated BP, and sodium intake estimated via 24 hour sodium excretion. In total, 167 studies were included that compared dietary sodium intakes <120 mmol with >150 mmol. In studies on subjects with elevated BP, the median trial duration was 28 days,and the average 24 hour sodium excretion in the trials were 71 mmol in the low-salt intake groups and 196 mmol in the high salt groups. In studies on subjects with normal BP, the median trial duration was 7 days, and the average 24 hour sodium excretion in the trials were 50 mmol in the low-salt intake groups and 201 mmol in the high salt groups.

Outcomes were systolic (SBP), diastolic (DSP), and mean BP (MBP), renin, aldosterone, adrenaline, noradrenaline, triglyceride, cholesterol, LDL, and HDL. The results were also analyzed by race.

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Dietary sulforaphane reduces oxidative stress in diabetes

Type 2 diabetes is characterized by increased oxidative stress, which may result in vascular pathologies (Bekyarova, Ivanova, and Madjova, 2007). Certain dietary phytochemicals may ameliorate oxidative stress and restore a more normal metabolic milieu. As reviewed by Angeloni, Leoncini, Malaguti, Angelini, Hrelia, and Hrelia (2009), one such phytochemical found in cruciferous vegetables such as broccoli sprouts, sulforaphane (SFN), induces phase-II enzymes and increases endogenous antioxidant activity, as confirmed in vitro (Piao et al., 2005; Xue et al., 2008; Zhu et al., 2008), in rodents (Wu et al., 2004; Cho et al., 2006; Piao et al., 2005), and in healthy humans (Murashima et al., 2004; Riedl et al., 2009). To verify that these effects extend to diabetic populations, Bahadoran, Mirmiran, Hosseinpanah, Hedayati, Hosseinpour-Niazi, and Azizi (2011) tested broccoli sprouts powder (BSP) on biomarkers of oxidative stress in diabetics.

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Hedonic hunger is increased with obesity and normalized with gastric bypass surgery

The increasingly convoluted relationship of appetite and obesity has recently been suggested by Lowe and Butyrn (2007) to be partially mediated by a mechanism referred to as “hedonic hunger,” or the craving for foods in the absence of energy needs. As gastric bypass surgery results in several neurobiological changes that may impact hedonic hunger, data in this population as well as obese subjects who have not undergone the surgery were collected in a recent study by Schultes, Ernst, Wilms, Thurnheer, and Hallschmid (2010). Their work compared subjective hedonic hunger between these and nonobese subjects to evaluate the influence from obesity and gastric bypass surgery and test the hypothesis that hedonic hunger may be a factor in the etiology of obesity.

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Latest Cochrane review on dietary fats and cardiovascular disease

Right on the heels of the updated Cochrane review on “Reduced dietary salt for the prevention of cardiovascular disease,” (and the terrible reporting on it), another one is updated: “Reduced or modified dietary fat for preventing cardiovascular disease.” One of the authors (Lee Hooper) worked on the salt review as well.

Given that this is a Cochrane review, it uses only RCTs (and only studies that tracked morbidity and mortality, not just intermediate risk factors). Of course as always, the caveats of basing overall conclusions on topics only on RCTs should be noted, but given that this issue has so much data from different study designs, I was curious if the conclusions from the new Cochrane would match recent publications:

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Nutritional Blogma is now nutsci.org

After nearly 2 years of blogging and nearly 2 years of planning the blog’s name change, I finally got to it this weekend. Nutritional Blogma (recomp.com/blogma) is now nutsci.org.  If you have a moment, please click through and let me know if anything doesn’t work properly.

Why?

Short and easier to remember, more relevant to my broad interests in nutritional science.

If you for chance link to me in a blogroll please update at your convenience, though I will be leaving the redirect up from the old domain for a long time so existing links to individual articles will automatically redirect to their new page.  Thanks!

Shaky science journalism at SciAm on salt

Melinda Wenner Moyer, a journalist at Scientific American, recently published a new article titled: It’s Time to End the War on Salt.  I was anxious to read an article with such a dramatic headline (do I need to adjust my perspective?) as Melinda strikes me as progressive and current with articles such as this one that covers recent research suggesting we switch the hard focus off saturated fat and onto refined carbohydrates.  After reading the article and digging deeper, however, I found that most of the article’s references didn’t support the conclusions, and in fact there are some glaring errors that sometimes completely misrepresent scientists and their research.  As with most nutritional issues, there are many ambiguities and disagreements in the literature and you can find evidence to support whatever side you want.  The salt research is especially difficult to navigate, as the debate has been intensively ongoing for decades.  In my opinion, Moyer missed an opportunity to show the public what is still contentious, instead only looking to develop a one-sided piece to downplay the advice we have been told for years she thinks is wrong: to watch how much salt we eat.  This post is not meant to get into extreme detail of the debate but to show what is incorrect about the article.

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Averaged restaurant stated calorie values accurate overall (but only 7% within 10 kcal); lower calorie sit-down entrees less so

Note: the original title was misleading in that I wrote “on average stated calories are accurate”, but really only 7% were within 10 kcal of what is posted. Averaged together they are accurate, but individually they are not.

Restaurants have been estimated to account for about 35% of american energy intake (USDA data), so it is important that customers are provided accurate information about how many calories they are consuming should they be monitoring their intakes.  A previous pilot study by a research group led by Susan Roberts of Tufts suggested lower calorie foods may have more calories than what are listed.  One other small study found on average that posted calorie values are accurate.  But studies of larger sample sizes and varieties are needed.  These are the results of their (Roberts et al.) new study, published today in JAMA. Continue reading

Severe childhood obesity and state intervention

I’ve been following David Ludwig’s commentaries in JAMA with interest lately; some of recent that I especially enjoyed:

So I was excited to see on Tuesday that another was published: State Intervention in Life-Threatening Childhood Obesity (with Lindsey Murtagh).  I uploaded the full text here.   Continue reading

Increase in number of eating occasions, more than increases in food portion sizes or energy density per meal responsible for increased energy intake at the population level?

We know by now that an increase in calorie consumption since the 1970s by about 500 Calories per day for Americans is primarily fueling obesity.  Physical activity decline at the population level is a lesser contributor (and it is contentious if the ‘decline’ is significant).  For references, see those from Yoni’s presentation in this post.  What is lesser known at this point is why people are eating more- what factors have the most influence on how much we eat per day?  There are many theories, and an important new paper in PLoS Medicine by Kiyah Duffey and Barry Popkin (whose credentials are impressive) gives us more insight into the relative contributions of some of them (and they are a bit counter-intuitive to conventional wisdom).

They identified 3 main theories that obesity research centralizes on (quoted from the paper):

  • increases in the frequency of eating/drinking occasions, especially snacking (EO)
  • increases in the typical portion sizes of foods and beverages (PS)
  • changes in the energy density of the foods consumed (termed “volumetrics” by Rolls and colleagues) (ED)

Each of these have small supportive bodies of research, but they have not yet been studied together.  So this study looked at relative contributions of changes in EO frequency, and PS and ED of the EOs to changes in total energy (TE) intake in adults between 1977 and 2006 in the U.S.

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Why the “chocolate milk diet” won’t work

This piece was written by myself and Travis Saunders of the Obesity Panacea blog.  As it is cross posted on both blogs, i’ve disabled comments here. Please visit his blog if you would like to comment.

Through Twitter this gem of an article: “The Chocolate Milk Diet” got our BS detectors blaring, published last year by the editor-in-chief of Men’s Health and Women’s Health, David Zinczenko.

Usually I (Colby) ignore these kind of things, but the article was so nonsensical that I felt it needed to be critiqued, especially considering the huge audience it probably reached and influenced (it received over 2,000 Facebook likes on Yahoo alone! And think of the reach of the Men’s Health magazine).  Articles like this really do health professionals a disservice, as they spread bad nutrition information around like wildfire; it is no wonder people don’t know what advice to follow.  And of course many other health and fitness organizations including Goodlife, Running Room, and Livestrong.com are also on the chocolate milk bandwagon (the latter two are proudly mentioned in this press release from the Dairy Farmer’s of Canada), such that it is almost impossible to avoid the the chocolate milk media machine.  In the face of a barrage of such one-sided  information, we can sometimes benefit from a reminder that, as Yoni Freedhoff puts it, “milk is not a magic fairy food that confers the health of immortal unicorns”. So here is our passage-by-passage rebuttal to The Chocolate Milk Diet (emphasis ours).

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