As 2009 comes to an end, it is time to reflect on some of this year’s scientific advancements.
Please comment here, by email, or twitter on how I am doing with the blog so far. Though I only started it a few months ago in September, I hope it has been a benefit to at least a few people. I am very detail oriented, so posts will roll out slowly, and with over 40 topics already in draft, 2010 will be a busy year!
Happy new year!
Here are short comments on some of my favorite studies of this year.
Colman RJ, Anderson RM, Johnson SC, et al. Caloric restriction delays disease onset and mortality in rhesus monkeys.; 2009:201-4. Available at: www.ncbi.nlm.nih.gov/pubmed/19590001.
An update to the Rhesus monkey calorie restriction longitudinal study, now at 20 years, shows an 80% survival (and reduction of various diseases) in the calorie restricted group compared to 50% left in the control.
Ishikura Y, Ikeda G, Akimoto K, et al. Arachidonic Acid Supplementation Decreases P300 Latency and Increases P300 Amplitude of Event-Related Potentials in Healthy Elderly Men. Neuropsychobiology. 2009;60(2):73-79. Available at: www.ncbi.nlm.nih.gov/pubmed/19752581.
Arachidonic acid is a nutrient despised by many nutritionists, but essential for nervous system development. New research suggests is may be important to maintain some aspects of cognitive function in adults as well. Reviewed on this blog here.
Bailey SJ, Winyard P, Vanhatalo A, et al. Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans. Journal of Applied Physiology. 2009. Available at: jap.physiology.org/cgi/doi/10.1152/japplphysiol.00722.2009.
Building on a study from 2 years ago, a recent study found that high nitrate vegetable juice (beet root) reduces the oxygen cost of exercise and improves time to exhaustion. Reviewed on this blog here.
Barrès R, Osler ME, Yan J, et al. Non-CpG methylation of the PGC-1alpha promoter through DNMT3B controls mitochondrial density. Cell metabolism. 2009;10(3):189-98. Available at: www.ncbi.nlm.nih.gov/pubmed/19723495.
A gene that regulates mitochondrial biogenesis, central to insulin resistance, is found to be hypermethylated in diabetics. In vitro experiments showed under what conditions this can happen and even which DNA methyltransferase isoform is involved, furthering our understanding of how epigenetics contributes to insulin resistance and suggesting possible treatment targets. Reviewed on this blog here.
Cannell JJ, Hollis BW, Sorenson MB, Taft TN, Anderson JJ. Athletic performance and vitamin D. Medicine and science in sports and exercise. 2009;41(5):1102-10. Available at: www.ncbi.nlm.nih.gov/pubmed/19346976.
A great review on some esoteric research dating back decades on how vitamin D concentration seems to influence athletic performance. I am assisting in a current study on this subject, which will be published next year. Expect to see posts about it soon.
Carrano AC, Liu Z, Dillin A, Hunter T. A conserved ubiquitination pathway determines longevity in response to diet restriction. Nature. 2009;1:1-5. Available at: www.ncbi.nlm.nih.gov/pubmed/19553937.
Further elucidation of mechanisms through which calorie restriction works.
Cheng Y, Meng Q, Wang C, et al. Leucine deprivation decreases fat mass by stimulation of lipolysis in WAT and upregulation of UCP1 in BAT. Diabetes. 2009;(June). Available at: www.ncbi.nlm.nih.gov/pubmed/19833890.
Deprivation of essential amino acids regulate fat mass. Detailed blog post coming soon.
Dangour AD, Dodhia SK, Hayter A, et al. Nutritional quality of organic foods: a systematic review. The American journal of clinical nutrition. 2009;(C):4-9. Available at: www.ncbi.nlm.nih.gov/pubmed/19640946.
A large review concludes that organic foods aren’t superior to non in a number of nutrients, though the issue is more complex.
Dean JT, Tran L, Beaven S, et al. Resistance to diet-induced obesity in mice with synthetic glyoxylate shunt. Cell metabolism. 2009;9(6):525-36. Available at: www.ncbi.nlm.nih.gov/pubmed/19490907.
The first study that adds a synthetic (non native) metabolic pathway from different species into mice, showing benefit to health.
Ebbing M, Bonaa KH, Nygard O, et al. Cancer Incidence and Mortality After Treatment With Folic Acid and Vitamin B12. JAMA: The Journal of the American Medical Association. 2009;302(19):2119-2126. Available at: jama.ama-assn.org/cgi/doi/10.1001/jama.2009.1622.
The evidence continues to mount that too much folic acid and B12 has harmful consequences.
Felton aM, Felton a, Raubenheimer D, et al. Protein content of diets dictates the daily energy intake of a free-ranging primate. Behavioral Ecology. 2009;20(4):685-690. Available at: www.beheco.oxfordjournals.org/cgi/doi/10.1093/beheco/arp021.
Adding to protein leverage theory, spider monkeys consume energy to satisfy protein requirements, while total energy intake varies.
Frassetto La, Schloetter M, Mietus-Synder M, Morris RC, Sebastian a. Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. European journal of clinical nutrition. 2009;63(8):947-55. Available at: www.ncbi.nlm.nih.gov/pubmed/19209185.
A “paleo” diet improves health, though many people would disagree on how to define this type of diet. More on paleo type diets in 2010.
Goodson JM, Groppo D, Halem S, Carpino E. Is Obesity an Oral Bacterial Disease? Journal of Dental Research. 2009.
Adding to the body of research showing certain bacterial populations change with obesity and perhaps that they may have a causal role in some cases. “Infectobesity” has been studied by measuring bacteria in the gut, but this one yields interesting oral data.
Hall KD, Guo J, Dore M, Chow CC. The Progressive Increase of Food Waste in America and Its Environmental Impact. Energy. 2009;4(11):9-14.
Americans waste about 40% of our food, which is an increase from previous data.
Kokkinos A, le Roux CW, Alexiadou K, et al. 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. 2009;95(January):1-5. Available at: www.ncbi.nlm.nih.gov/pubmed/19875483.
A recent study showed differences in 2 gut hormones that influence appetite, are differed depending on eating speed. But a close look at the study and previous literature suggest that is probably isn’t much to worry about. Reviewed on this blog here.
Kroese FM, Evers C, De Ridder DT. How chocolate keeps you slim: The effect of food temptations on weight watching goal importance, intentions, and eating behavior. Appetite. 2009. Available at: www.ncbi.nlm.nih.gov/pubmed/19666065.
Human behavior is important to understand when considering eating habits. Contrary to what might be assumed, 2 experiments suggest that food temptations actually may improve compliance to healthy eating.
LeSauter J, Hoque N, Weintraub M, Pfaff DW, Silver R. Stomach ghrelin-secreting cells as food-entrainable circadian clocks. Proceedings of the National Academy of Sciences of the United States of America. 2009;106(32):13582-7. Available at: www.ncbi.nlm.nih.gov/pubmed/19633195.
Food influences peripheral circadian clocks, including stomach cells. A close examination of these clocks coming in 2010.
Place N. Go rinse your mouth: a novel way to improve endurance performance? The Journal of physiology. 2009;587(Pt 11):2425-6. Available at: www.ncbi.nlm.nih.gov/pubmed/19332497.
Carbohydrate enhances performance during exercise of ~1 hour not by being used as a fuel source, but by modulating a yet unknown pathway in the mouth to the brain to reduce fatigue.
Tardy A, Lambert-Porcheron S, Malpuech-Brugère C, et al. Dairy and industrial sources of trans fat do not impair peripheral insulin sensitivity in overweight women. The American journal of clinical nutrition. 2009;90(1):88-94. Available at: www.ncbi.nlm.nih.gov/pubmed/19474135.
Observational studies have demonized trans fat and led to their banning in some cities. This study suggests that some of our conclusions may have been premature.
Stumvoll M, Kahn CR, Blu M. Antioxidants prevent health-promoting effects of physical exercise in humans ¨. Clinical Chemistry. 2009;2(12):2-7.
Another study suggesting that classic vitamin-antioxidants perhaps shouldn’t be included as supplements in diets, at least around exercise. Mitohormesis/antioxidant/exercise research review coming in 2010.
Sumien N, Heinrich KR, Shetty RA, Sohal RS, Forster MJ. Prolonged Intake of Coenzyme Q10 Impairs Cognitive Functions in Mice. The Journal of nutrition. 2009;(C):3-9. Available at: www.ncbi.nlm.nih.gov/pubmed/19710165.
Health benefits of dietary nutrients are dose dependent. CoQ10 is no different, and actually worsens cognitive function with too high a dose.
Beher D, Wu J, Cumine S, et al. Resveratrol is not a direct activator of SIRT1 enzyme activity. Chemical biology & drug design. 2009;74(6):619-24. Available at: www.ncbi.nlm.nih.gov/pubmed/19843076.
Resveratrol does not activate SIRT1 directly as previously hyped, rather the target seems to be AMPK. Seems to be an experimental artifact.
Bondesen Ba, Mills ST, Pavlath GK. The COX-2 pathway regulates growth of atrophied muscle via multiple mechanisms. American journal of physiology. Cell physiology. 2009;290(6):C1651-9. Available at: www.ncbi.nlm.nih.gov/pubmed/16467402.
COX, classically regulating production of eicosanoids, also have a role in the control of muscle mass. The research on NSAID use and resulting implications will be reviewed in a post sometime in the next year.
Harrison DE, Strong R, Sharp ZD, et al. Rapamycin fed late in life extends lifespan in genetically heterogeneous mice. Nature. 2009:1-5. Available at: www.nature.com/doifinder/10.1038/nature08221.
The NIA recently started testing a number of substances, each at 3 separate centers for better data. Rapamycin (mTOR inhibitor) is the first drug that can be qualified as having life extension properties in mice, even when started late in life. More studies are in progress on rapamycin and other compounds. It will still be a stretch for human application.
Gottlieb B, Chalifour LE, Mitmaker B, et al. BAK1 gene variation and abdominal aortic aneurysms. Human mutation. 2009;30(7):1043-7. Available at: www.ncbi.nlm.nih.gov/pubmed/19514060.
Genome-wide analysis generally use saliva or blood samples to analyze gene variants. This intriguing study found that between blood cells and tissue cells, BAK1 SNPs differed, in both diseased and normal subjects. It may mean that instead of genetics having a significant effect on disease, intra and extracellular milieu may select for minority SNPs as a consequence. This also adds further evidence that pathologies may not fit the traditional somatic mutation theories.
Pérez VI, Bokov A, Remmen HV, et al. Is the oxidative stress theory of aging dead? Biochimica et biophysica acta. 2009. Available at: www.ncbi.nlm.nih.gov/pubmed/19524016.
Decades ago, free radicals were implicated in the ageing process. While specific radicals in mitochondrial may have a role, in general the theory has been debunked with numerous antioxidant administrations and endogenous antioxidant gene manipulations showing no effect on lifespan in rodents.
Alvergne A, Lummaa V. Does the contraceptive pill alter mate choice in humans? Trends in ecology & evolution (Personal edition). 2009:1-9. Available at: www.ncbi.nlm.nih.gov/pubmed/19818527.
A great review on the evidence that contraceptive pills are altering mate selection for both genders. Perhaps it is time to be more proactive on this issue?
Blaauw B, Canato M, Agatea L, et al. Inducible activation of Akt increases skeletal muscle mass and force without satellite cell activation. The FASEB journal : official publication of the Federation of American Societies for Experimental Biology. 2009;23(11):3896-905. Available at: www.ncbi.nlm.nih.gov/pubmed/19661286.
This study adds clarity to the issue of when satellite cells are required for hypertrophy. Overload and testosterone appear to require their activation, while the Akt pathway does not.
Heisenberg M. Is free will an illusion? Nature. 2009;459(May).
Free will is a heated topic in neuroscience, and this short article summarizes the issue well.
Miller GE, Chen E, Fok AK, et al. Low early-life social class leaves a biological residue manifested by decreased glucocorticoid and increased proinflammatory signaling. Current. 2009:1-6.
Poverty is one of the biggest factors influencing disease risk later in life, and we are starting to find mechanistic reasons why.
Milner CE, Cote KA. Benefits of napping in healthy adults: impact of nap length, time of day, age, and experience with napping. Journal of sleep research. 2009;18(2):272-81. Available at: www.ncbi.nlm.nih.gov/pubmed/19645971.
Many cultures take naps, and its effects on health and performance are intriguing.
Sharot T, Shiner T, Brown AC, Fan J, Dolan RJ. Dopamine Enhances Expectation of Pleasure in Humans. Current biology : CB. 2009:1-4. Available at: www.ncbi.nlm.nih.gov/pubmed/19913423.
L-DOPA (dopamine) alters prediction of future pleasure (but not as a reward chemical itself as often wrongly suggested).
Barrick JE, Yu DS, Yoon SH, et al. Genome evolution and adaptation in a long-term experiment with Escherichia coli. Nature. 2009;461(7268):1243-7. Available at: www.ncbi.nlm.nih.gov/pubmed/19838166.
An update to a 20 year experiment (40,000 generations) tracking evolution of E. coli.
Kapogiannis D, Barbey AK, Su M, et al. Cognitive and neural foundations of religious belief. PNAS. 2009;(3):1-6.
Evidence that religious belief seems to have hijacked evolutionary neural networks involved in emotion, abstract semantics, imagery, and more. The fact that it was funded by the NIH is even better!
Campbell A, Hausenblas Ha. Effects of exercise interventions on body image: a meta-analysis. Journal of health psychology. 2009;14(6):780-93. Available at: www.ncbi.nlm.nih.gov/pubmed/19687115.
Exercise improves many aspects of health independent of weight loss, including body image. This meta-analysis on the issue was recently published.