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Critically discussing nutrition related research.
Colby
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- December 22, 2010
- 12:00 AM
- 1,808 views
Holidays & weight gain: what the science suggests
by Colby in nutsci.org
Many people have the perception that they are likely to gain 5 or 10 pounds during the holiday season (Thanksgiving to after New Year’s Day). This myth has been propagated by media (4), perhaps partially explaining why it exists. But … Continue reading →... Read more »
Andersson I, & Rössner S. (1992) The Christmas factor in obesity therapy. International journal of obesity and related metabolic disorders : journal of the International Association for the Study of Obesity, 16(12), 1013-5. PMID: 1335971
Rees, S., Holman, R., & Turner, R. (1985) The Christmas feast. BMJ, 291(6511), 1764-1765. DOI: 10.1136/bmj.291.6511.1764
Reid, R., & Hackett, A. (1999) Changes in nutritional status in adults over Christmas 1998. Journal of Human Nutrition and Dietetics, 12(6), 513-516. DOI: 10.1046/j.1365-277x.1999.00205.x
Yanovski, J., Yanovski, S., Sovik, K., Nguyen, T., O'Neil, P., & Sebring, N. (2000) A Prospective Study of Holiday Weight Gain. New England Journal of Medicine, 342(12), 861-867. DOI: 10.1056/NEJM200003233421206
Hull HR, Hester CN, & Fields DA. (2006) The effect of the holiday season on body weight and composition in college students. Nutrition , 44. PMID: 17192197
Costa CI, Moreira PII, & Teixeira VIII. (2007) HOLIDAY WEIGHT GAIN IN UNIVERSITY STUDENTS. Alimentação Humana. info:/
Phelan S, Wing RR, Raynor HA, Dibello J, Nedeau K, & Peng W. (2008) Holiday weight management by successful weight losers and normal weight individuals. Journal of consulting and clinical psychology, 76(3), 442-8. PMID: 18540737
- November 13, 2009
- 09:00 AM
- 1,640 views
Eating speed and calorie control: Weight of the evidence
by Colby in nutsci.org
Recently, a paper by Kokkinos et al. (1) was published on an experiment finding different postprandial Peptide YY and Glucagon-Like Peptide-1 concentration responses with varying eating speed. This immediately prompted such media headlines as: “Eating Slowly May Help Weight Control,” “Cut Calories by Eating Slowly,” “Eating Slowly Can Help with Weight Loss,” and “Eating Quickly [...]... Read more »
Kokkinos A, le Roux CW, Alexiadou K, Tentolouris N, Vincent RP, Kyriaki D, Perrea D, Ghatei MA, Bloom SR, & Katsilambros N. (2009) Eating Slowly Increases the Postprandial Response of the Anorexigenic Gut Hormones, Peptide YY and Glucagon-Like Peptide-1. The Journal of clinical endocrinology and metabolism. PMID: 19875483
Gaul, D., Craighead, E., & Mahoney, M. (1975) Relationship between eating rates and obesity. Journal of Consulting and Clinical Psychology, 43(2), 123-125. DOI: 10.1037/h0076522
Marston AR, London P, Cohen N, & Cooper LM. (1977) In vivo observation of the eating behavior of obese and nonobese subjects. Journal of consulting and clinical psychology, 45(2), 335-6. PMID: 850018
Andrade AM, Greene GW, & Melanson KJ. (2008) Eating slowly led to decreases in energy intake within meals in healthy women. Journal of the American Dietetic Association, 108(7), 1186-91. PMID: 18589027
- April 12, 2011
- 05:00 PM
- 1,591 views
Private nonprofit foundations & Public Health: Potential conflicts of interest in corporate links
by Colby in nutsci.org
Corporate involvement in public health is a sensitive topic, but one I am largely against. It is pretty clear that corporations usually get the benefit of bettering their brand image (which is often largely unhealthy processed products) at a low … Continue reading →... Read more »
David Stuckler, Sanjay Basu, & Martin McKee. (2011) Global Health Philanthropy and Institutional Relationships: How Should Conflicts of Interest Be Addressed?. PLoS Medicine. info:/10.1371/journal.pmed.1001020
- February 9, 2011
- 10:08 PM
- 1,331 views
Epidemiological evidence that UV exposure & vitamin D independently may reduce multiple sclerosis risk
by Colby in nutsci.org
Last year, I wrote about a mouse study that suggested UVB exposure suppressed a model of multiple sclerosis (MS) independent of vitamin D production. So I was excited to see media reports this week covering another study, this one epidemiological … Continue reading →... Read more »
Lucas RM, Ponsonby AL, Dear K, Valery PC, Pender MP, Taylor BV, Kilpatrick TJ, Dwyer T, Coulthard A, Chapman C.... (2011) Sun exposure and vitamin D are independent risk factors for CNS demyelination. Neurology, 76(6), 540-8. PMID: 21300969
- December 1, 2009
- 09:00 AM
- 1,265 views
Water intake and protein:carbohydrate ratio confound Drosophilia calorie restriction studies, implications?
by Colby in nutsci.org
Ja et al. (1) recently published the results of a study exploring how hydration and nutrient manipulation effects the results of calorie restriction in Drosophilia.
In non mammalian models, feeding rate is difficult to control, and often food is diluted with water without giving them a separate source of water. Therefore, the specimens could be dehydrated [...]... Read more »
Ja WW, Carvalho GB, Zid BM, Mak EM, Brummel T, & Benzer S. (2009) Water- and nutrient-dependent effects of dietary restriction on Drosophila lifespan. Proceedings of the National Academy of Sciences of the United States of America, 106(44), 18633-7. PMID: 19841272
- March 3, 2011
- 08:00 AM
- 1,132 views
Athletes: obey your thirst
by Colby in nutsci.org
Tim Noakes has a nice review paper in the Annals of Nutrition & Metabolism on hydration for athletes: Is Drinking to Thirst Optimum? It is open access at least for now. In short, Noakes makes a convincing case that drinking … Continue reading →... Read more »
Timothy David Noakes . (2011) Is Drinking to Thirst Optimum? . Annals of Nutrition . info:/10.1159/000322697
- February 14, 2011
- 10:06 PM
- 1,092 views
“Antioxidants” in chocolate (and fruit): don’t buy the hype
by Colby in nutsci.org
Last week, just in time for Valentine’s day (clever science marketing or lucky peer review speed?), Hershey announced that cocoa is a “super fruit” with a paper in the Chemistry Central Journal (open access). Here is a random sampling of … Continue reading →... Read more »
Crozier SJ, Preston AG, Hurst WJ, Payne MJ, Mann J, Hainly L, & Miller DL. (2011) Cacao seeds are a "Super Fruit": A comparative analysis of various fruit powders and products. Chemistry Central journal, 5(1), 5. PMID: 21299842
- March 8, 2011
- 09:12 PM
- 1,036 views
Gene-environment interaction database related to nutritional phenotypes
by Colby in nutsci.org
Larry Parnell (Twitter, Blog), Yu-Chi Lee, Chao-Qiang Lai, & Jose Ordovas (Twitter) took what must have been an enormous amount of time and put together a database of gene-environment interactions related to lipids, cardiovascular disease, and diabetes. I had no idea this … Continue reading →... Read more »
Yu-Chi Lee, Chao-Qiang Lai, Jose M Ordovas, & Laurence D Parnell. (2011) A Database of Gene-Environment Interactions Pertaining to Blood Lipid Traits, Cardiovascular Disease and Type 2 Diabetes. Data Mining in Genomics . info:/10.4172/2153-0602.1000106
- March 24, 2011
- 10:30 PM
- 1,028 views
Human serum metabolome (better) quantified
by Colby in nutsci.org
An important paper in PLoS One was published last month by Psychogios et al. that details a huge effort that yielded the most comprehensive characterization of the human serum metabolome yet. I recommend reading the paper if you are casually … Continue reading →... Read more »
Psychogios N, Hau DD, Peng J, Guo AC, Mandal R, Bouatra S, Sinelnikov I, Krishnamurthy R, Eisner R, Gautam B.... (2011) The human serum metabolome. PloS one, 6(2). PMID: 21359215
- April 14, 2011
- 08:00 AM
- 976 views
A consensus paper on dietary fats and cardiovascular disease
by Colby in nutsci.org
The AJCN has a nice short “consensus” paper from many of the top researchers examining the supposed link between saturated fat and cardiovascular disease, which is open access here. Arne Astrup and Walter Willett organized an invitation-only symposium last year … Continue reading →... Read more »
Arne Astrup, Jørn Dyerberg, Peter Elwood, Kjeld Hermansen, Frank B Hu, Marianne Uhre Jakobsen, Frans J Kok, Ronald M Krauss, Jean Michel Lecerf, Philippe LeGrand.... (2011) The role of reducing intakes of saturated fat in the prevention of cardiovascular disease: where does the evidence stand in 2010?. The American Journal of Clinical Nutrition. info:/10.3945/ajcn.110.004622
- August 12, 2011
- 10:30 AM
- 973 views
Latest Cochrane review on dietary fats and cardiovascular disease
by Colby Vorland in nutsci.org
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:
The “consensus” article as blogged about here
The 2 meta-analyses last year: one on prospective cohorts on saturated fats and CVD (Siri-Tarino et al.), and the other on RCTs that increase PUFA in place of saturated fats (Mozaffarian et al.) as discussed here
The 2009 paper by Skeaff & Miller on prospective cohorts, RCTs, and coronary heart disease here (PDF)
Note: If you want a short summary directly from Lee Hooper, the Cochrane site has a short podcast here.
This is an updated review to the 2001 report that included 27 trials that were at least 6 months duration with over 18000 subjects total. This yielded only over 1400 deaths, over 800 cardiovascular deaths, and over 1200 cardiovascular events, and found no clear relationship between altering fat content in the diet and cardiovascular mortality, but reducing saturated fat did reduce cardiovascular events by 16%.... Read more »
Hooper L, Summerbell CD, Thompson R, Sills D, Roberts FG, Moore H, & Davey Smith G. (2011) Reduced or modified dietary fat for preventing cardiovascular disease. Cochrane Database of Systematic Reviews. info:/10.1002/14651858.CD002137.pub2.
- February 11, 2011
- 06:00 AM
- 972 views
Mitochondrial membrane alpha-tocopherol/homologues: super scavengers or peroxidase inhibitors?
by Colby in nutsci.org
I love research that alters established dogma with new technology (hence Nutritional Blogma), so I felt compelled to highlight this one. Polyunsaturated fatty acids (PUFAs) are structurally important in cell and some organelle membranes. For simplicity’s sake, we are often … Continue reading →... Read more »
Samhan-Arias AK, Tyurina YY, & Kagan VE. (2011) Lipid antioxidants: free radical scavenging versus regulation of enzymatic lipid peroxidation. Journal of clinical biochemistry and nutrition, 48(1), 91-5. PMID: 21297919
- May 13, 2011
- 08:00 AM
- 963 views
Generational increases in stochastic epigenetic variability to sustained methyl donor supplementation in mice
by Colby in nutsci.org
This recent paper in PLoS Genetics by Cheryl C. Y. Li and colleagues (from a group that did earlier work with the agouti mouse model) was really fascinating- they looked at changes in methylation variability in response to dietary supplementation … Continue reading →... Read more »
Li CC, Cropley JE, Cowley MJ, Preiss T, Martin DI, & Suter CM. (2011) A sustained dietary change increases epigenetic variation in isogenic mice. PLoS genetics, 7(4). PMID: 21541011
- September 9, 2009
- 09:00 AM
- 957 views
Hydrolyzed protein versus intact: effects on nitrogen partitioning
by Colby in nutsci.org
In the sports nutrition industry, there is a gradual shift to using hydrolyzed proteins for their increased speed of absorption and inducing hyperleucemia and hyperinsulinemia, conditions that may promote a faster and greater response to recovery and skeletal muscle growth. A recent paper by Deglaire et al. confirms this is the case for casein protein, [...]... Read more »
Deglaire A, Fromentin C, Fouillet H, Airinei G, Gaudichon C, Boutry C, Benamouzig R, Moughan PJ, Tomé D, & Bos C. (2009) Hydrolyzed dietary casein as compared with the intact protein reduces postprandial peripheral, but not whole-body, uptake of nitrogen in humans. The American journal of clinical nutrition. PMID: 19692493
- May 13, 2011
- 08:00 AM
- 936 views
Generational increases in stochastic epigenetic variability to sustained methyl donor supplementation in mice
by Colby in nutsci.org
This recent paper in PLoS Genetics by Cheryl C. Y. Li and colleagues (from a group that did earlier work with the agouti mouse model) was really fascinating- they looked at changes in methylation variability in response to dietary supplementation … Continue reading →... Read more »
Li CC, Cropley JE, Cowley MJ, Preiss T, Martin DI, & Suter CM. (2011) A sustained dietary change increases epigenetic variation in isogenic mice. PLoS genetics, 7(4). PMID: 21541011
- March 29, 2011
- 10:32 PM
- 930 views
Evidence-based nutrition: is proof of efficacy for nutrients too high?
by Colby in nutsci.org
…evidence-based nutrition (EBN), has seemingly swallowed EBM [evidence-based medicine] whole without either asking how well it might fit, or adapting it to the unique features of the nutrition context evidence-based nutrition (EBN), has seemingly swallowed EBM whole without either asking how well it might … Continue reading →... Read more »
Robert P. Heaney, Connie M. Weaver, & Jeffrey Blumberg. (2011) EBN (Evidence-Based Nutrition)Ver. 2.0. Nutrition Today. info:/10.1097/NT.0b013e3182076fdf
Blumberg J, Heaney RP, Huncharek M, Scholl T, Stampfer M, Vieth R, Weaver CM, & Zeisel SH. (2010) Evidence-based criteria in the nutritional context. Nutrition reviews, 68(8), 478-84. PMID: 20646225
- June 28, 2011
- 05:00 PM
- 869 views
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?
by Colby in nutsci.org
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 … Continue reading →... Read more »
Duffey KJ, & Popkin BM. (2011) Energy Density, Portion Size, and Eating Occasions: Contributions to Increased Energy Intake in the United States. PLoS Med. info:/10.1371/journal.pmed.1001050
- October 5, 2009
- 10:00 AM
- 866 views
Arachidonic acid and cognitive function in the elderly
by Colby in nutsci.org
Arachidonic acid. The very word makes most nutritionists cringe. Many of us are taught to avoid it like the plague. Americans have developed an egg-phobia because of it (the misinterpretations of egg research will be reviewed in a later post). How can something that biochemically competes with our beloved omega 3s be good for [...]... Read more »
Ishikura Y, Ikeda G, Akimoto K, Hata M, Kusumoto A, Kidokoro A, Kontani M, Kawashima H, Kiso Y, & Koga Y. (2009) Arachidonic Acid Supplementation Decreases P300 Latency and Increases P300 Amplitude of Event-Related Potentials in Healthy Elderly Men. Neuropsychobiology, 60(2), 73-79. PMID: 19752581
- February 9, 2011
- 12:47 AM
- 866 views
Quercetin paradox in a complex antioxidant network
by Colby in nutsci.org
This is sort of a random post, but I remember coming across this paper from 2007 awhile back titled “The quercetin paradox” that shows how quercetin protects against some oxidative damage in a lung cell line but the oxidation product … Continue reading →... Read more »
Jacobs H, Moalin M, Bast A, van der Vijgh WJ, & Haenen GR. (2010) An essential difference between the flavonoids monoHER and quercetin in their interplay with the endogenous antioxidant network. PloS one, 5(11). PMID: 21079733
- September 4, 2009
- 12:00 PM
- 830 views
The confounding role of sensory perception in calorie restriction and ageing research
by Colby in nutsci.org
My first post to this blog will begin with a thought provoking paper on how the olfactory system fits in to the longevity promoting effects of calorie restriction.
Calorie restriction is the most studied and reliable way to extend secondary and maximal lifespan, tested in many species since the 1930’s up to recently in rhesus monkeys and preliminary human data.
Why the mechanisms of calorie restriction have been so well conserved throughout species is still an enigma; species in natural settings do not tend to die of old age, they do well beforehand. Reproductive purposes is a popular theory, and evidence supports calorie restriction as an adaptation during periods of nutritional deprivation to extend the reproductive period. This I will review in more detail in future posts. With unifying mechanisms still largely elusive, most theories have explored the impact of the energy content itself on physiological changes to a species.
Environmental cues are becoming increasing appreciated for controlling behavior in many fields; it is no surprise that many external factors influence food consumption. Building evidence explored in this paper suggests that not only the actual consumption, but simply the perception may in fact have physiological consequences on healthspan for the better or worse.
The longevity mediated effect of calorie restriction, concluded by Dr. Pletcher, seems to be partially from a reduced perception of food availability, and partially from the restriction of nutrients themselves. Other research suggests other factors such as methionine or glycotoxins in a diet may be largely responsible for the effect of calorie restriction on lifespan, which will be reviewed in other posts. This research complicates the matter further, adding odor as a variable.
Pletcher describes experiments by his lab in Drosophilia showing a fast modulation of lifespan when nutritional environments are changed, suggesting that sensory perception may be an ignored factor. They studied olfaction because of gene expression data showing odor sensing related genes were altered by both age and nutrient availability.
They then tested if odorants or the lack of from live yeast affected the lifespan of Drosophilia, by allowing one group to see and smell the yeast but not consume it, and another was denied seeing or smelling yeast. Indeed, the group exposed to the yeast suffered a reduced lifespan, but only when subjected to calorie restriction. Compared to controls who consumed the yeast, however, they still lived longer. This seems to suggest that olfaction is partly involved in the longevity promotion of calorie restriction, with another part coming from biological mechanisms, with possible overlap between the two.
Next they knocked out a gene known to be required for normal functioning of the majority of Drosophilia olfactory receptors , Or83b. Female mutants experienced about a 50% increase in median lifespan in both low and high nutrient conditions, while the males also lived longer but with a lesser increase than the females. They also noted that the mutants had a normal size and metabolic rate but are resistant to starvation and hyperoxia, and the females increased triglyceride storage, suggesting alterations of other physiological mechanisms by a reduced sensory perception.
Pletcher describes research by Alcedo and Kenyon in C. elegans, selectively targeting specific sensory neurons with laser ablation, showing roles of gustatory and olfactory neurons on lifespan; with some increasing and some decreasing it. Pletcher and his group are currently testing if specific gene knockouts or overexpressions and claim to have identified certain neuron populations that influence longevity and the pathways in which they affect target tissues. Their long term goal:
“…to elucidate the network that couples sensory perception to longevity-from signaling inputs and their associated neurocircuits that detect and decode sensory information; to endocrine cells, hormone identity, and transport that relay that information to target tissues; to transcriptional complexes and gene targets; to transcriptional complexes and gene targets that ensure cell, tissue, and organism survival.”
Cool, this will be fun to watch unfold!
This begs the question if calorie restriction in its fullest in humans in a Westernized culture is even possible anymore, with food abundance and sensory overload difficult to avoid. It also raises interesting possibilities of mechanisms of longevity regulation that may be lost with such a variety of food choices and combinations in a modern world.... Read more »
Pletcher, S. (2009) The Modulation of Lifespan by Perceptual Systems. Annals of the New York Academy of Sciences, 1170(1), 693-697. DOI: 10.1111/j.1749-6632.2009.04926.x
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