All posts in Alzheimer’s Disease

Languages Protect from Memory Loss

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People who speak more than two languages may lower their risk of memory loss or developing other memory problems, according to a study released today that will be presented at the American Academy of Neurology’s 63rd Annual Meeting in Honolulu April 9 to April 16, 2011. “It appears speaking more than two languages has a protective effect on memory in seniors who practice foreign languages over their lifetime or at the time of the study,” said study author Magali Perquin, PhD, with the Center for Health Studies from the Public Research Center for Health (“CRP-Santé”) in Luxembourg. Perquin is helping to lead the MemoVie study which involves a consortium of partners from different hospitals and institutions.

The study involved 230 men and women with an average age of 73 who had spoken or currently spoke two to seven languages. Of the participants, 44 reported memory loss or cognitive problems; the rest of the group had no memory issues. Researchers discovered that those people who spoke four or more languages were five times less likely to develop memory loss or cognitive problems compared to those people who only spoke two languages. People who spoke three languages were three times less likely to have memory loss or cognitive problems compared to bilinguals. In addition, people who currently spoke more than two languages were also four times less likely to have memory loss or cognitive impairment. The results accounted for the age and the education of the participants.

“Further studies are needed to try to confirm these findings and determine whether the protection is limited to thinking skills related to language or if it also extends beyond that and benefits other areas of cognition,” said Perquin. The research was conducted in Luxembourg, where there is a dense population of people who speak more than two languages. The MemoVie study was supported by The National Research Fund (FNR) from Luxembourg.

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Mediterranean diet cuts Alzheimer’s

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Alzheimer’s disease, a major form of dementia, has no cure. Luckily, diet and lifestyle can be modified to reduce the risk. For instance, Mediterranean diet and physical activity may each independently reduce the risk of the condition, according to a study in the Aug 2009 issue of Journal of American Medical Association. Dr. N. Scarmeas and colleagues of Taub Institute for Research in Alzheimer’s Disease and the Aging Brain and Department of Neurology at Columbia University Medical Center found men and women those who adhered most closely to Mediterranean diet were 40 percent less likely to be diagnosed with Alzheimer’s disease during a average of 5.4-year follow-up, compared to those who adhered to the diet least closely.

The researchers also found those who most actively engaged in physical activity were up to 33 percent less likely to be diagnosed with Alzheimer’s compared with those who were least active. For the study, Scarneas et al. followed 1880 community-dwelling elderly people who lived without dementia at baseline in New York for their dietary habits and physical activity.

Adherence to a Mediterranean-style diet was assessed on a scale of 0-9, or trichotomized into low, middle, or high and dichotomized into low and high. Physical activity was trichotomized into no physical activity, some, and much and dichotomized into low and high. Neurological and neuropsychological measures were conducted about every 1.5 years from 1992 to 2006. During the 5.4-year follow-up, 282 incident cases of Alzheimer’s were identified.

Those who adhered to the Mediterranean diet with a high score were at 40 percent reduced risk of Alzheimer, compared to those on the diet with a low score. A Mediterranean diet with a middle score did not seem to help compared to a diet with a low score. Those who engaged in some physical activity or much physical activity were at a 25 percent or 33 percent reduced risk of Alzheimer’s disease, respectively, compared with those who did no physical activity. Men and women who had neither followed Mediterranean diet nor much physical activity had an absolute Alzheimer’s risk of 19 percent. This is compared to 12 percent for those who followed both high scored Mediterranean diet and engaged in much physical activity – a difference of 45 percent.

The researchers concluded “both higher Mediterranean-type diet adherence and higher physical activity were independently associated with reduced risk for AD (Alzheimer’s disease).”

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Yet another benefit of green tea

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For thousands of years, the people of China, Japan, India, and Thailand have consumed green tea and used it medicinally to treat everything from headaches to heart diseases. Over the past few decades, however, research in both Asia and the West have taken place providing scientific evidence of green tea’s numerous health benefits. As a whole, studies indicate that regular consumption of green tea may slow or prevent conditions including high cholesterol, heart disease, arthritis, impaired immune disease and liver disease. In yet another recent study on the beverage’s healthful properties, published in the academic journal Phytomedicine, researchers have found evidence that enzymes in the drink may help in fighting Alzheimer’s and other forms of dementia.

Researchers at the Newcastle University have also found that the Chinese brew may also play a vital role in guarding against cancer. The Newcastle team focused on whether or not once the tea was in the digestive system if the protective properties were still as effective. “What was really exciting was that we found when green tea is digested, the resulting chemicals are actually more effective against key triggers of Alzheimer’s,” said Ed Okello, from the university’s School of Agriculture, Food and Rural Development. “The digested compounds also had anti-cancer properties, significantly slowing down the growth of tumour cells which we were using in our experiments,” Okello said.

Previous studies have shown that polyphenols, present in black and green tea, bind with the toxic compounds and protect brain cells. When ingested, the polyphenols are broken down to produce a mix of compounds and it was these the team tested in their research. According to Okello, there are many factors that together have an influence on diseases such as cancer and dementia – a good diet, plenty of exercise and a healthy lifestyle are all important. “But I think it’s fair to say that at least one cup of green tea a day may be good for you and I would certainly recommend it,” he added.

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Protective properties of green tea

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Regularly drinking green tea could protect the brain against developing Alzheimer’s and other forms of dementia. The study, published in the academic journal Phytomedicine, also suggests this ancient Chinese remedy could play a vital role in protecting the body against cancer. Led by Dr Ed Okello, the Newcastle team wanted to know if the protective properties of green tea – which have previously been shown to be present in the undigested, freshly brewed form of the drink – were still active once the tea had been digested. Digestion is a vital process which provides our bodies with the nutrients we need to survive. But, says Dr Okello, it also means that just because the food we put into our mouths is generally accepted to contain health-boosting properties, we can’t assume these compounds will ever be absorbed by the body.

“What was really exciting about this study was that we found when green tea is digested by enzymes in the gut, the resulting chemicals are actually more effective against key triggers of Alzheimer’s development than the undigested form of the tea,” explains Dr Okello, based in the School of Agriculture, Food and Rural Development at Newcastle University and executive director of the university’s Medicinal Plant Research Group. “In addition to this, we also found the digested compounds had anti-cancer properties, significantly slowing down the growth of the tumour cells which we were using in our experiments.”

As part of the research, the Newcastle team worked in collaboration with Dr Gordon McDougall of the Plant Products and Food Quality Group at the Scottish Crop Research Institute in Dundee, who developed technology which simulates the human digestive system. It is this which made it possible for the team to analyse the protective properties of the products of digestion. Two compounds are known to play a significant role in the development of Alzheimer’s disease – hydrogen peroxide and a protein known as beta-amyloid. Previous studies have shown that compounds known as polyphenols, present in black and green tea, possess neuroprotective properties, binding with the toxic compounds and protecting the brain cells.

When ingested, the polyphenols are broken down to produce a mix of compounds and it was these the Newcastle team tested in their latest research. “It’s one of the reasons why we have to be so careful when we make claims about the health benefits of various foods and supplements,” explains Dr Okello. “There are certain chemicals we know to be beneficial and we can identify foods which are rich in them but what happens during the digestion process is crucial to whether these foods are actually doing us any good.” Carrying out the experiments in the lab using a tumour cell model, they exposed the cells to varying concentrations of the different toxins and the digested green tea compounds.

Dr Okello explained: “The digested chemicals protected the cells, preventing the toxins from destroying the cells. “We also saw them affecting the cancer cells, significantly slowing down their growth. Green tea has been used in Traditional Chinese medicine for centuries and what we have here provides the scientific evidence why it may be effective against some of the key diseases we face today.”

The next step is to discover whether the beneficial compounds are produced during digestion after healthy human volunteers consume tea polyphenols. The team has already received funding from the Biotechnology and Biological Sciences Research Council (BBSRC) to take this forward. Dr Okello adds: “There are obviously many factors which together have an influence on diseases such as cancer and dementia – a good diet, plenty of exercise and a healthy lifestyle are all important. “But I think it’s fair to say that at least one cup of green tea every day may be good for you and I would certainly recommend it.”

(Source: Newcastle University: Phytomedicine)

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Low Level of “Good” Cholesterol Associated with Alzheimer’s

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A low level of “good” cholesterol is a well-known risk factor for heart disease. A new study by investigators at Columbia University College of Physicians & Surgeons now suggests that a low level of good cholesterol may also raise the risk of developing Alzheimer's disease.

“Low levels of 'good' cholesterol (a.k.a. high-density lipoproteins or HDL) are very common in the United States,” says the study's lead author, Christiane Reitz, MD, PhD, assistant professor of neurology (in the Sergievsky Center and Taub Institute). “If raising HDL can lower a person's risk of developing Alzheimer's disease, that means we may be able to significantly reduce the rate of Alzheimer's disease in the population,” Reitz says, though she cautions that the finding still must be confirmed in other studies.

The study, which appears in the December issue of Archives of Neurology, is co-authored with Jose Luchsinger, MD, MPH, associate professor of medicine and epidemiology, and Richard Mayeux, MD, director of the Gertrude Sergievsky Center and Sergievsky Professor of Neurology, Psychiatry, and Epidemiology.

Previously, the relationship between HDL and Alzheimer's disease had been unclear. Some studies found an association, but others, including one of Reitz's own, found no connection. The new study, Reitz says, follows subjects for a longer period of time than previous studies, resulting in a more accurate account of the number of subjects who ultimately develop Alzheimer's.

After monitoring 1130 elderly residents of northern Manhattan for an average of four years, the researchers found a 40 percent higher incidence of Alzheimer's in residents with low HDL (less than 55 mg/dl). The reason that low HDL is associated with a higher rate of Alzheimer's isn't understood. One possibility is that it works through stroke. “We know low HDL raises the risk of stroke and that stroke is associated with Alzheimer's, so stroke may be the mediator,” Reitz says. “But there's also evidence that HDL works by itself to clear amyloid proteins [the proteins believed to cause Alzheimer's] from the brain.”

Because the study included a large number of African Americans and Hispanics, unlike previous studies that focused on whites, the finding may indicate that low HDL is linked to a high risk of Alzheimer's in many different ethnicities.

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Fish oil enhances effect of Green Tea on Alzheimers

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Fish oil, when combined with epigallocatechin‑3‑gallate (EGCG—a polyphenol and antioxidant found in green tea), may affect chemical processes in the brain associated with Alzheimer's disease, according to a study published in Neuroscience Letters. This study, which used an animal (mouse) model of Alzheimer's disease, builds on previous research linking the disease to peptides (amino acid chains) called beta‑amyloids and laboratory studies suggesting that EGCG decreases memory problems and beta‑amyloid deposits in mice.

Researchers from the University of South Florida divided Alzheimer's disease‑model mice into five feeding groups. During a period of 6 months, each group was fed one of five diets: fish oil only; high‑dose EGCG; low‑dose EGCG; low‑dose EGCG and fish oil; or a regular diet (control). The researchers observed that low‑dose EGCG alone did not reduce the Alzheimer's disease-related chemical processes in the brain. However, the mice fed the combination of fish oil and EGCG had a significant reduction in amyloid deposits that have been linked with Alzheimer's disease.

Upon examination of blood and brain tissues of the mice, the researchers found high levels of EGCG in the mice that were fed the combination of fish oil and low‑dose EGCG compared with those fed low‑dose EGCG alone. A possible explanation, according to the researchers, is that fish oil enhances the bioavailability of EGCG—that is, the degree to which EGCG was absorbed into the body and made available to the brain. This effect, in turn, may contribute to the increased effectiveness of this combination. Further research is necessary, however, to determine if the combination of fish oil and EGCG affects memory or cognition, and whether it might have potential as an option for people at risk of developing Alzheimer's disease.

Reference

Giunta B, Hou H, Zhu Y, et al. Fish oil enhances anti‑amyloidogenic properties of green tea EGCG in Tg2576 mice. Neuroscience Letters. 2010;471(3):134–138.

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Dementia Can Be Avoided By Reading, Eating Well And Keeping Spirits High

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According to the study published today in the British Medical Journal, the combined effects of reading, eating well and keeping spirits high would far outstrip the theoretical possibility of eliminating a gene known to increase the risk of dementia.

Dr. Karen Ritchie, a neuro-psychologist at the French National Institute of Medical Research leading her team of researchers assessed the change in the cognitive ability of 1,433 pensioners in Montpellier, over a period of seven years.

The participants in the study were asked series of questions regarding their lifestyle, medical history and educational background, including carrying out reading tests.

According to their findings, the amount of intellectual exercise a person indulges in greatly influences their likelihood of developing dementia.

Those with lower reading scores were 18% more likely to develop mild cognitive impairment or dementia, the former the forerunner of the latter.

Those suffering from depression were 10% more likely to develop it; while eating fruit and vegetables less than twice a day meant a 6.5% chance of developing dementia. Having diabetes was also a significant factor, leading to a 5% higher risk than those without.

In comparison, possessing a gene associated with dementia increased the risk by 7%.

These findings indicate intellectual activity to be the most important factor, which means the public health message should be to encourage literacy at all ages irrespective of innate ability.

Similarly, while the study found depression to be strongly linked to the development of dementia, treating it did not necessarily offer protection, nor was it easy getting people to eat more fruit and vegetables.

In conclusion, due to these problems, the most practical short-term solution was tackling diabetes, previous studies have also confirmed to be a causal factor. Obesity, high blood pressure and high cholesterol are other risk factors associated with the disease.

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Depression Increases Risk of Alzheimer’s

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The study involved participants in the Chicago Health and Aging Project, a longitudinal study of risk factors for Alzheimer's disease involving a population of older adults on Chicago's south side. At three year intervals, the entire population completed a brief self-report measure of depressive symptoms and clinical evaluations for Alzheimer's disease.

Initial analyses focused on a group of 357 individuals who developed Alzheimer's disease during the course of the study. The study found a barely perceptible increase in depressive symptoms, a rate of 0.04 symptoms per year, during six to seven years of observation before the diagnosis of Alzheimer's disease and no change during two to three years of observation after the diagnosis.

Because dementia may reduce the accuracy of self-report, in a subgroup of 340 participants, researchers conducted additional analyses of change in depressive symptoms by interviewing family, friends and other who were close to the study participants. Neither Alzheimer's disease nor its precursor, mild cognitive impairment, was associated with change in depressive symptoms during a mean of three years of observation.

The results were consistent across all demographics. There was no evidence that sex, age, education or race modified the trajectory of depressive symptoms before or after Alzheimer's disease was diagnosed.

“Here is this terrible disease that robs people of who they are and their ability to function and yet it doesn't make them depressed,” said Wilson. “Alzheimer's may disrupt the ability to have prolonged bouts of negative emotions, in much the same way it disrupts many other activities.”

The study authors suggest additional studies of patients with Alzheimer's disease for longer periods to determine if depressive symptoms may eventually decrease as the disease becomes more severe.

In addition, researchers at Rush continue to look at why depression increases the risk of Alzheimer's disease.

The study was supported by funding from the National Institutes of Health (NIH)/ National Institute on Aging (NIA). Co-authors include G.M. Hoganson, BS; K.B. Rajan, PhD; L.L. Barnes, PhD; C.F. Mendes de Leon, PhD; and D.A. Evans, MD.

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Vitamin E May Reduce Dementia Risk

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The prospective Rotterdam Study involved 5,395 people over age 55 with no dementia at baseline. All of the participants, who lived in one section of the Rotterdam area, provided dietary information when the study began in 1990.

The researchers previously reported a similar association of vitamin E intake with a lower risk of dementia and Alzheimer's disease over six years of follow-up among the cohort.

The current study found that after 9.6 years of follow-up, 465 of the participants had developed dementia; 365 of these cases were classified as Alzheimer's disease.

Higher baseline vitamin E consumption correlated with lower long-term risk of dementia in models minimally adjusted for age only and those adjusted for age, education, apolipoprotein genotype, total caloric intake, alcohol and smoking habits, body mass index, and use of supplements (both P=0.02 for trend).

Dietary surveys indicated that margarine was by far the biggest contributor to vitamin E intake at 43.4%, followed by sunflower oil at 18.5%, butter at 3.8%, and cooking fats at 3.4%.

Participants with vitamin E intakes in the top third, averaging 18.5 mg per day, were 25% less likely to develop dementia of any kind over almost 10 years of follow-up than those in the bottom third, who averaged only 9.0 mg per day. Higher baseline vitamin E consumption correlated with lower long-term risk of dementia (both P=0.02 for trend).

While the top versus bottom tertile comparison was significant, the middle group with vitamin E intake averaging 13.5 mg per day was no less likely to develop dementia than the lowest intake group.

For Alzheimer's disease alone, the multivariate-adjusted risk was 26% lower among those with the highest intake compared with the lowest (95% confidence interval 3% to 44%, P=0.03 for trend). But intermediate intake again appeared to have no impact.

Other antioxidants — vitamin C, beta-carotene, and flavonoids — held no significant associations with dementia or Alzheimer's disease risk (multivariate adjusted P=0.50 to >0.99 for trend).

Sensitivity analyses excluding participants who reported taking supplements at baseline showed similar results.

The researchers noted that the vitamin intakes seen in the study were consistent with a typical Western diet but cautioned about the possibility of residual confounding in the observational results.

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Teenage Physical Activity Reduces Risk of Cognitive Impairment in Later Life

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Of the participants, 15.5%, 29.7%, 28.1%, and 21.1% reported being physically inactive at teenage, at 30 years, at 50 years, and in late life respectively; the increase in cognitive impairment for those who were inactive was between 50% and 100% at each time point. When physical activity measures for all four ages were entered into a single model and adjusted for variables such as age, education, marital status, diabetes, hypertension, depressive symptoms, smoking, and BMI, only teenage physical activity status remained significantly associated with cognitive performance in old age.

Middleton added, “As a result, to minimize the risk of dementia, physical activity should be encouraged from early life. Not to be without hope, people who were inactive at teenage can reduce their risk of cognitive impairment by becoming active in later life.”

The researchers concluded that the mechanisms by which physical activity across the life course is related to late life cognition are likely to be multi-factorial. There is evidence to suggest that physical activity has a positive effect on brain plasticity and cognition and in addition, physical activity reduces the rates and severity of vascular risk factors, such as hypertension, obesity, and type II diabetes, which are each associated with increased risk of cognitive impairment.

“Low physical activity levels in today's youth may mean increased dementia rates in the future. Dementia prevention programs and other health promotion programs encouraging physical activity should target people starting at very young ages, not just in mid- and late life,” said Middleton.

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