aging

Fish oil supplements provide no benefit to brain power

April, 2010

The largest ever trial of fish oil supplements has found no evidence that they offer benefits for cognitive function in older people. However, neither the trial group or the placebo group showed any cognitive decline over the two-year period of the study.

The largest ever trial of fish oil supplements has found no evidence that they offer benefits for cognitive function in older people. The British study enrolled 867 participants aged 70-80 years, and lasted two years. After two years, those receiving fish oil capsules had significantly higher levels of omega-3 fatty acids in their blood than those receiving placebo capsules. However, cognitive function did not decline in either group over the period. The researchers caution that it may be that more time is needed for benefits to show.

Reference: 

[170] Dangour, A. D., Allen E., Elbourne D., Fasey N., Fletcher A. E., Hardy P., et al.
(2010).  Effect of 2-y n-3 long-chain polyunsaturated fatty acid supplementation on cognitive function in older people: a randomized, double-blind, controlled trial.
Am J Clin Nutr. ajcn.2009.29121 - ajcn.2009.29121.

Source: 

http://www.eurekalert.org/pub_releases/2010-04/lsoh-fos042110.php

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What causes word finding failures in young and older adults

Journal Article: 

Burke, D.M., MacKay, D.G., Worthley, J.S. & Wade, E. (1991). On the tip of the tongue: What causes word finding failures in young and older adults. Journal of Memory and Language, 30, 542-579.

  • Failing to immediately retrieve well-known information does become more common with age.
  • An increase in "tips of the tongue" is evident as early as the mid-thirties.
  • The increase in memory failures applies to names of people and things; abstract words do not get harder to recall.
  • The length of time before the missing word is recalled also increases with age.
  • Older people tend to be less likely than younger people to actively pursue a missing word.

It is common for people to feel as they get older that they more frequently experience occasions when they cannot immediately retrieve a word they know perfectly well ("it's on the tip of my tongue").

Tips of the tongue (TOTs) do indeed increase with age, and this increase is evident as early as the mid-thirties. There are other differences however, in the TOT experiences as people age. For example, older adults are much more likely to "go blank" than either young or mid-age (35-45) adults. That is, younger adults are more likely to be able to retrieve some information about the target word.

At all ages, the most common type of word involved in TOTs is proper names. But while forgetting proper names and object names becomes more common as we get older, interestingly, abstract words are forgotten less.

The most common means of resolution at all ages is that the forgotten word simply "pops up", but as we get older, it takes longer before this happens. "Pop-ups" are relatively more common for older adults. It is suggested that this may be because they are less likely to actively attempt to retrieve the information. According to a questionnaire, older adults are more likely to simply relax and think about something else.

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Age differences in the allocation of study time

Journal Article: 

Dunlosky, J. & Connor, L.T. (1997). Age differences in the allocation of study time account for age differences in memory performance. Memory and Cognition, 25, 691-700.

  • It is well-established that older adults commonly need to practice more than younger adults to achieve the same level of performance.
  • It may be that such age deficits in remembering are at least partly due to poorer monitoring of their learning.

It has been well-established that, compared to younger adults, older adults require more practice to achieve the same level of performance1. Sometimes, indeed, they may need twice as much2.

In the present study, two groups of adult subjects were given paired items to learn during multiple study-test trials. During each trial items were presented at the subject's pace. Afterwards the subjects were asked to judge how likely they were to be able to recall each item in a test.

It was found that people were very good at accurately judging the likelihood of their correct recall. Correlations between judgments and the amount of time the subjects studied the items suggested that people were monitoring their learning and using this to allocate study time.

However, older adults (with a mean age of 67) used monitoring to a lesser degree than the younger adults (with a mean age of 22), and the results suggested that part of the reason for the deficit in recall commonly found with older adults is due to this factor.

References

1. For a review, see Kausler, D.H. 1994. Learning and memory in normal aging. New York: Academic Press.

2. Delbecq-Derousné, J. & Beauvois, M. 1989. Memory processes and aging: A defect of automatic rather than controlled processes? Archives of Gerontology & Geriatrics, 1 (Suppl), 121-150.

Salthouse, T.A. & Dunlosky, J. 1995. Analyses of adult age differences in associative learning. Zeitschrift für Psychologie, 203, 351-360

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Low vitamin D levels associated with poorer cognition in older men

April, 2008

A study of over 3,100 older men (49-71) from across Europe has found that men with higher levels of vitamin D performed consistently better in an attention and speed of processing task. There was no difference on visual memory tasks. Although previous studies have suggested low vitamin D levels may be associated with poorer cognitive performance, findings have been inconsistent. Vitamin D is primarily synthesised from sun exposure but is also found in certain foods such as oily fish.

Reference: 

[825] McCann, J. C., & Ames B. N.
(2008).  Is there convincing biological or behavioral evidence linking vitamin D deficiency to brain dysfunction?.
FASEB J.. 22(4), 982 - 1001.

Source: 

http://www.eurekalert.org/pub_releases/2009-05/uom-vdf051909.php

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Vitamin D important in brain development and function

May, 2009

A review described as “definitive” has concluded that there is ample biological evidence to suggest an important role for vitamin D in brain development and function, and that supplementation for groups chronically low in vitamin D is warranted. Vitamin D has long been known to promote healthy bones, but more recently has been found to have a much broader role — over 900 different genes are now known to be able to bind the vitamin D receptor. Evidence for vitamin D's involvement in brain function includes the wide distribution of vitamin D receptors throughout the brain, as well as its ability to affect proteins in the brain known to be directly involved in learning and memory and motor control. Because we receive most of our Vitamin D from sunlight (UV from the sun converts a biochemical in the skin to vitamin D), those with darker skin living in northern latitudes are particularly at risk of vitamin D deficiency. Nursing infants and the elderly are also particularly vulnerable. It has also argued that current recommendations set the recommended level of vitamin D too low. This review is the fourth in a series that critically evaluate scientific evidence linking deficiencies in micronutrients to brain function. Earlier reviews have looked at DHA, choline, and iron.

Reference: 

[614] Casanueva, F. F., Finn J. D., Forti G., Giwercman A., Han T. S., Huhtaniemi I. T., et al.
(2009).  Association between 25-hydroxyvitamin D levels and cognitive performance in middle-aged and older European men.
Journal of Neurology, Neurosurgery & Psychiatry. 80(7), 722 - 729.

Source: 

http://www.eurekalert.org/pub_releases/2008-04/chr-vdi041808.php

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'Cocktail' for improved memory

January, 2008

A study has found that gerbils given a ‘cocktail’ of DHA, uridine and choline performed significantly better on learning and memory tests than untreated gerbils, and their brains had up to 70% more phosphatides (a type of molecule that forms cell membranes) than controls, suggesting that new synapses are forming. Some of the gerbils received all three compounds and some received only two; the improvements were greatest in those given all three. An earlier study had found that the treatment improved function in rats with cognitive impairment. Omega-3 fatty acids are found in fish, eggs, flaxseed and meat from grass-fed animals. Choline is found in meats, nuts and eggs. Uridine cannot be obtained from food sources, but is a component of human breast milk and can be produced in the body.

Reference: 

[859] Holguin, S., Martinez J., Chow C., & Wurtman R.
(2008).  Dietary uridine enhances the improvement in learning and memory produced by administering DHA to gerbils.
FASEB J.. 22(11), 3938 - 3946.

Source: 

http://www.eurekalert.org/pub_releases/2008-07/miot-spt070808.php

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