Older news items (pre-2010) brought over from the old website
Cognitive benefit of reduced calories for older adults
Recent rat studies have indicated that significant calorie restriction lengthens lives, but the evidence for humans is rather more mixed. Now a German study of 50 healthy but overweight older adults (average age 60) has found that those who were on a balanced but severely restricted diet (reduced by 30%) for 3 months significantly improved their performance on a verbal memory test. Those who didn’t reduce their calorie intake but increased their consumption of unsaturated fatty acids (linked to improved cognition), and those who didn’t change their diets, showed little or no improvement. It’s important to note that the participants were overweight to start with; further research will be needed to see whether the same effect occurs with normal-weight older adults.
Witte, A. V., Fobker, M., Gellner, R., Knecht, S., & Floel, A. (2009). From the Cover: Caloric restriction improves memory in elderly humans. Proceedings of the National Academy of Sciences, 106(4), 1255-1260. Retrieved from http://www.pnas.org/content/early/2009/01/26/0808587106
http://sciencenow.sciencemag.org/cgi/content/full/2009/127/1?etoc
Calorie restriction may help prevent Alzheimer's
A mouse study has found that beta-amyloid peptides can be reduced by restricting calorie intake, primarily through a low carbohydrate diet. Conversely, a high caloric intake based on saturated fat was shown to increase levels of beta-amyloid peptides. This is the first study to suggest that caloric restriction might inhibit the generation of beta-amyloid peptides, but there have been a number of studies providing evidence that high cholesterol, obesity, and other cardiovascular risk factors increase the likelihood of Alzheimer’s.
Qin, W. et al. 2006. Neuronal SIRT1 Activation as a Novel Mechanism Underlying the Prevention of Alzheimer Disease Amyloid Neuropathology by Calorie Restriction. Journal of Biological Chemistry, 281 (31), 21745-21754.
http://www.sciencedaily.com/releases/2006/06/060614113128.htm
Fewer calories may slow Alzheimer's
Restricting the diets of genetically engineered mice by 40% over 4 weeks reduced the build-up of plaques in the brain that are linked to Alzheimer's disease by 50%. It remains to be seen whether such dietary changes would similarly affect humans. Researchers are now looking to isolate the specific factors of the diet restriction which are important.
Patel, N.V., Gordon, M.N., Connor, K.E., Good, R.A., Engelman, R.W., Mason, J., Morgan, D.G., Morgan, T.E. & Finch, C.E. (in press). Caloric restriction attenuates Aβ-deposition in Alzheimer transgenic models. Neurobiology of Aging, In Press, Corrected Proof, Available online 25 November 2004.
http://www.eurekalert.org/pub_releases/2004-12/uosc-fcm121404.php
Calorie restriction leads to some brain benefits but not others in mice
A mouse study has found that although severe calorie restriction prevents certain aging-related changes in the brain, such as the accumulation of free radicals, and impairments in coordination and strength, the reduced diet did not seem to prevent age-related cognitive impairment.
Dugan, L.L. et al. 2004. Presented on Sunday, Oct. 24 at Neuroscience 2004, the Society for Neuroscience's 34th Annual Meeting in San Diego.
http://www.eurekalert.org/pub_releases/2004-10/wuso-crl102204.php
Meal skipping protects the nerve cells of mice
A new mouse study suggests fasting every other day may protect brain neurons as well as or better than either vigorous exercise or caloric restriction. The mice were allowed to eat as much as they wanted on non-fasting days, and did not, overall, eat fewer calories than the control group. Their nerve cells however, proved to be more resistant to neurotoxin injury or death than nerve cells of both the calorie-restricted mice or the control group. Previous research has found that meal-skipping diets can stimulate brain cells in mice to produce a protein called brain-derived neurotrophic factor (BDNF) that promotes the survival and growth of nerve cells. The researchers are now investigating the effects of meal-skipping on the cardiovascular system in laboratory rats.
Anson, M., Guo, Z., de Cabo, R., Iyun, T., Rios, M., Hagepanos, A., … Mattson, M. P. (2003). Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake. Proceedings of the National Academy of Sciences of the United States of America, 100(10), 6216-6220. Retrieved from http://www.pnas.org/content/100/10/6216.abstract
http://www.eurekalert.org/pub_releases/2003-04/nioa-msh042403.php
Calorie restriction reduces age-related brain cell death
A recent rat study has shown that certain proteins that increase with age and are linked to cell death were significantly reduced in the brains of rats whose calories were limited (but nutritionally dense, to guard against malnutrition). Moreover, the levels of a beneficial protein known to protect against neuron death were twice as high in older rats whose calories were restricted by 40%. This is consistent with a number of studies of other species that have found calorie restriction not only boosts life span and general health but also increases mental capacity.
Shelke, R. R., & Leeuwenburgh, C. (2003). Life-long calorie restriction (CR) increases expression of apoptosis repressor with a caspase recruitment domain (ARC) in the brain. FASEB J., 02-0803fje . Retrieved from http://www.fasebj.org/cgi/content/abstract/02-0803fjev1
http://www.eurekalert.org/pub_releases/2003-01/uof-usc010903.php