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).”
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.
Eating purple fruits such as blueberries and drinking green tea can help ward off diseases including Alzheimer’s, Multiple Sclerosis and Parkinson’s, a University of Manchester report claims. New research from Professor Douglas Kell, published in the journal Archives of Toxicology, has found that the majority of debilitating illnesses are in part caused by poorly-bound iron which causes the production of dangerous toxins that can react with the components of living systems. These toxins, called hydroxyl radicals, cause degenerative diseases of many kinds in different parts of the body. In order to protect the body from these dangerous varieties of poorly-bound iron, it is vital to take on nutrients, known as iron chelators, which can bind the iron tightly.
Brightly-coloured fruits and vegetables are excellent sources of chelators, as is green tea, with purple fruits considered to have the best chance of binding the iron effectively. However, despite conflicting reports, the widely-publicised benefits of red wine seem to work in a different way, and have no similar benefits, Professor Kell’s paper noted.
This new paper is the first time the link has been made between so many different diseases and the presence of the wrong form of iron, and gives a crucial clue as to how to prevent them or at least slow them down. Professor Kell argues that the means by which poorly-liganded iron accelerates the onset of debilitating diseases shows up areas in which current, traditional thinking is flawed and can be dangerous. For instance, Vitamin C is thought to be of great benefit to the body’s ability to defend itself against toxins and diseases. However Professor Kell, who is Professor of Bioanalytical Science at the University, indicates that excess vitamin C can in fact have the opposite effect to that intended if unliganded iron is present.
Only when iron is suitably and safely bound (“chelated”) will vitamin C work effectively. Professor Kell said: “Much of modern biology has been concerned with the role of different genes in human disease. “The importance of iron may have been missed because there is no gene for iron as such. What I have highlighted in this work is therefore a crucial area for further investigation, as many simple predictions follow from my analysis.
“If true they might change greatly the means by which we seek to prevent and even cure such diseases.”
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)
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.
A new UK research has found that more than a third believe cancer is down to fate and there is nothing they can do to avoid it. Cancer Research UK stated that one in five men and women feared cancer ahead of debt, knife crime, Alzheimer's disease and losing their job whereas 34 percent believed the disease was down to fate, rising to 41 percent of those aged 55 to 64.
The findings come in the midst of growing evidence suggesting lifestyle factors such as losing weight, taking exercise, reducing alcohol consumption and quitting smoking can significantly reduce the risk of developing cancer.
The survey questioned more than 2,000 adults aged 16 and over. Those questioned were asked to choose what they feared most from a list including developing Alzheimer's, being in debt, old age, being the victim of knife crime, cancer, being in a plane crash, motor neurone disease, being in a car accident, having a heart attack, losing your job and losing your home.
More people (20 per cent) overall chose cancer than anything else, followed by 16 per cent who feared Alzheimer's disease the most. Among adults up to the age of 44, cancer was feared most by 25 per cent while 7.5 per cent feared Alzheimer's most. For those aged over 65, Alzheimer's was feared most by 30 per cent while 14 per cent feared cancer most.
John Fyall, Cancer Research UK's spokesman for Scotland, said: “It's absolutely vital for us to get the message out that people can do something to alleviate their emphatic fear of cancer. Cancer is no longer the death sentence people still seem to dread,” the Scotsman quoted, John Fyall, Cancer Research UK's spokesman for Scotland, as saying. “Spotting early signs and symptoms of what could be cancer – but probably isn't – and getting these checked out by a doctor means that the disease can be diagnosed more quickly,” he added.
Teresa Nightingale, general manager of the World Cancer Research Fund, said, “It is a concern that so many people think cancer is a matter of fate, because there is now strong scientific evidence that people can make relatively simple changes to reduce their risk.” “Scientists estimate about a third of the most common cancers in the UK could be prevented just by eating a healthy, plant-based diet, being regularly physically active and maintaining a healthy weight. This includes about 40 per cent of breast and bowel cancer cases,” she added. Nightingale further informed that, “The strong evidence that diet, activity and weight affect our risk, together with other well-known risk factors such as smoking and sunburn, means that cancer is actually a largely preventable disease.” (ANI)
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.
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.
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.
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.
Dr. Gu and her colleagues studied a cohort of 2148 elderly subjects 65 years and older living in New York City. All subjects were healthy and free of dementia at study entry. Their dietary habits were obtained via questionnaire, and they were prospectively evaluated with the same standardized neurologic and neuropsychological measures approximately every 1.5 years for an average of 4 years.
The researchers used reduced rank regression to calculate dietary patterns according to their effect on 7 nutrients previously shown in the literature to be related to Alzheimer's disease: saturated fatty acids, monounsaturated fatty acids, ω-3 polyunsaturated fatty acids, ω-6 polyunsaturated fatty acids, vitamin E, vitamin B12, and folate.
During the follow-up, 253 individuals developed Alzheimer's disease. The study found that one dietary pattern — characterized by higher intakes of salad dressing, nuts, fish, tomatoes, poultry, cruciferous vegetables, fruits, and dark and green leafy vegetables and a lower intake of high-fat dairy products, red meat, organ meat, and butter — was significantly associated with a reduced risk for Alzheimer's disease.
Compared with subjects in the lowest tertile of adherence to this pattern, the Alzheimer's disease hazard ratio (95% confidence interval) for subjects in the highest tertile was 0.62 (0.43 – 0.89) after multivariable adjustment (P for trend = .01).
The study also found that subjects who were older, less educated, and current smokers tended to be less adherent to the protective diet. Hispanic individuals adhered less than white and black individuals (P = .02), and women tended to adhere more than men (P = .05).
“The dietary pattern that was most protective against Alzheimer's reflected a diet rich in ω-3 and ω-6 polyunsaturated fatty acids, vitamin E, and folate but poor in saturated fatty acids and vitamin B12,” commented Dr. Gu. “The combination of nutrients in this dietary pattern reflects multiple pathways in the development of Alzheimer's disease.
“For example, vitamin B12 and folate are homocysteine-related vitamins that may have an impact on the disease through their ability to lower circulating homocysteine levels,” she said. “Vitamin E is a strong antioxidant, and the fatty acids may be linked to dementia and cognitive function through atherosclerosis, thrombosis, or inflammation. Fatty acids may also affect brain development and membrane functioning.”
She added that the study has several limitations. “We used a single measurement of the diet, and this might not have captured the long-term dietary habits of the subjects. We also excluded subjects from the final analysis because they were lost to follow-up, and this might have introduced selection bias. We also can't completely rule out the possibility that the reduced risk associated with this protective diet was due to residual confounding.”
Further studies are planned, Dr. Gu said. “We cannot say based on this study alone that this type of dietary pattern prevents Alzheimer's disease, but many studies have consistently shown that fruits and vegetables and unsaturated fatty acids are associated with a lower risk. We want to repeat these findings in different populations and see if they can be confirmed in other studies.”
Commenting on this study for Medscape Neurology, David Knopman, MD, professor of neurology at the Mayo Clinic and a member of the Mayo Clinic Alzheimer's Disease Research Center in Rochester, Minnesota, said that, despite the study authors' best efforts, it is still not clear whether diet alone makes a difference.
“Dietary habits, which often are lifelong, are certainly part of the array of health behaviors that contribute to better cognitive health in late life. However, diet and other health behaviors are intertwined. Because a healthy diet contributes to better cardiac health, lower weight, lower blood pressure and a lower risk for diabetes, there are many reasons to view the dietary habits described by Dr. Gu and colleagues as beneficial.”
The study was supported by federal National Institute on Aging grants. Dr. Gu and Dr. Knopman have disclosed no relevant financial relationships.
Arch Neurol. Published online April 12, 2010.