High HDL Cholesterol Levels Associated With Reduced Alzheimer’s Risk

High levels of high-density lipoprotein (HDL), also known as “good” cholesterol, appear to be associated with a reduced risk for Alzheimer’s disease in older adults.

”Dyslipidemia [high total cholesterol and triglycerides] and late-onset Alzheimer’s disease are highly frequent in western societies,” the authors write as background information in the article. “More than 50 percent of the U.S. adult population has high cholesterol. About 1 percent of people age 65 to 69 years develop Alzheimer’s disease, and the prevalence increases to more than 60 percent for people older than 95 years.”

Christiane Reitz and colleagues studied 1,130 older adults to examine the association of blood lipid (fat) levels with Alzheimer’s disease. The study included a random sampling of Medicare recipients 65 or older residing in northern Manhattan, with no history of dementia or cognitive impairment. The researchers defined higher levels of HDL cholesterol as 55 milligrams per deciliter or more.

To determine this association, data were collected from medical, neurological and neuropsychological evaluations. Additionally, the authors assigned a diagnosis of “probable” Alzheimer’s disease when onset of dementia could not be explained by any other disorder. A diagnosis of “possible” Alzheimer’s disease was made when the most likely cause of dementia was Alzheimer’s disease but there were other disorders that could contribute to the dementia, such as stroke or Parkinson disease.

During the course of follow-up, there were 101 new cases of Alzheimer’s disease, of which 89 were probable and 12 were possible. The mean (average) age of individuals at the onset of probable and possible Alzheimer’s disease was 83 years, and compared with people who were not diagnosed with incident Alzheimer’s disease, those who did develop dementia were more often Hispanic and had a higher prevalence of diabetes at the start of the study. Higher plasma levels of HDL cholesterol were associated with a decreased risk of both probable and possible Alzheimer’s disease, even after adjusting for vascular risk factors and lipid-lowering treatments. Although higher plasma total cholesterol, non-HDL cholesterol and LDL cholesterol levels also were associated with decreased risks of probable and possible Alzheimer’s disease, these associations became non-significant after adjusting for vascular risk factors and lipid-lowering treatments.

“In this study, higher levels of HDL cholesterol were associated with a decreased risk of both probable and possible Alzheimer’s disease,” the authors conclude. “An important consideration in the interpretation of the results is that it was conducted in an urban multiethnic elderly community with a high prevalence of risk factors for mortality and dementia. Thus, our results may not be generalizeable to cohorts with younger individuals or to cohorts with participants with a lower morbidity [disease] burden.”

Arch Neurol. 2010;67(12):1491-1497. doi:10.1001/archneurol.2010.297.

One Week of Junk Food May Be Enough to Damage Your Memory

Feed your brain the right foods.

A new study from the University of New South Wales in Australia published in the journal Brain Behavior and Immunity, shows that just one week of eating an unhealthy diet is enough to cause lasting memory impairment in rats.

For a week, the rats were given access to a bottle of sugar water in addition to a healthy diet, or were fed a cafeteria-like diet loaded with cakes, cookies, and fat. Although only the rats on the cafeteria diet gained weight, both groups of rats had memory impairments compared with control animals who ate only healthy foods, suggesting that weight gain alone wasn’t to blame for their memory lapses.

Poor Diet Damages the Hippocampus

The rats had little trouble with object recognition, a type of memory that involves a brain region called the perirhinal cortex. But they did far worse with place recognition, a type of memory that involves a brain region called the hippocampus, which is responsible for many types of memory formation, including retaining new facts.

In the rats on the high-sugar or cafeteria diet, the researchers found that the hippocampus had become inflamed, impairing its function. The inflammation and memory damage lasted for at least three weeks after the rats were returned to a healthy diet.

Although rats aren’t a perfect model for humans, their hippocampus functions in very similar ways to ours. In humans and rats, the hippocampus not only helps us learn but also helps us navigate places and record events as they happen. Keeping it healthy is invaluable for learning and recall.

“A healthy diet is critical for optimum function,” said study author Professor Margaret Morris in an interview with Healthline. “Our data suggests that even several days of bad diet may impair some aspects of memory.”

The hippocampus is also used to regulate the body’s stress system. If it’s not able to do its job properly, stress can get out of control, dumping hormones into your bloodstream that will circulate back to the hippocampus and damage your memory further.

To complete the vicious circle, when stress levels are high, the body’s hunger systems shift. This causes you to selectively crave fatty and sugary foods. 

Memory and Age 

Although a little junk food here and there won’t have too much impact on a young person, a lifetime of poor eating can add up. If your hippocampus doesn’t get a chance to recover from the sugary, fatty onslaught, the inflammation could become long-term damage.

“Some studies show a decline in cognition with aging, and it is possible that an unhealthy diet may be particularly unhelpful in this group,” said Morris. Older brains take longer to recover from insults such as hangovers, so they might also be more vulnerable to damage from a junk food diet.

As seniors living on their own lose mobility, some are more likely to eat pre-packaged foods, such as frozen dinners, which tend to be high in fat, sugar, and salt. So this finding might also help explain the role that diet plays in the development of memory impairment in diseases like Alzheimer’s.

Green Tea Boosts Brain Power.

Sometimes, a good cup of tea really can clear your head and help you think more clearly. A daily habit of green tea may even promote the growth of brain cells and revitalize memory and learning capabilities.

Researchers at the University of California, Davis, have been studying how green tea influences brain function and boosts memory. Now Chinese researchers have confirmed findings that Green tea favorably affects the generation of brain cells and provides benefits for memory and spatial learning.

The compound in green tea responsible for boosting brain power is a chemical called epigallocatechin-3 gallate (EGCG). It’s an antioxidant that improves cognitive function by promoting growth and function of neurons (nerve cells) in the brain.

References

Green tea epigallocatechin-3-gallate (EGCG) promotes neural progenitor cell proliferation and sonic hedgehog pathway activation during adult hippocampal neurogenesis. Molecular Nutrition & Food Research Volume 56, Issue 8 1292–1303

Neural effects of green tea extract on dorsolateral prefrontal cortex. European Journal of Clinical Nutrition (2012) 66, 1187–1192;

Berries: The New Brain Food!

A study published this week in the Annals of Neurology suggests blueberries and strawberries slow the mental decline of aging. The study analyzed more than 16,000 women participating in the Nurses' Health Study. Women who ate berries more frequently over two decades showed slower decline in brain functions like memory and attention as they got older than those who had the fruits less often. Women who ate berries at least once a week slowed their cognitive decline by about 1.5 to 2.5 years. To see the effect, women had to consume about a half cup of blueberries or a cup of strawberries each week. The benefit is likely explained by a type of flavonoid called anthocyanidins, which are thought to help mitigate the effects of stress and inflammation that could play a role in cognitive decline.

Choline-rich diet tied to sharper memory.

People who get plenty of choline in their diets may perform better on memory tests, and be less likely to show brain changes associated with dementia, a new study suggests.

The study can only point to a correlation between memory and dietary choline -- a nutrient found in foods like saltwater fish, eggs, liver, chicken, milk and certain legumes, including soy and kidney beans.

The findings suggest that people with lower choline intakes were more likely to be on a "pathway" toward mental decline than their counterparts with higher intakes.

The findings, researchers say, do not mean that choline is the answer to staving off Alzheimer's disease -- the memory-robbing disease that affects 26 million people globally. But there's also reason to believe that choline matters. The nutrient is a precursor to the brain chemical acetylcholine, which plays a key role in memory and other cognitive functions; low acetylcholine levels are associated with Alzheimer's.

The study adds to evidence that your lifetime diet may make a difference in how your brain ages.

A number of studies, though not all, have found links between diet and Alzheimer's risk. Some suggest that Mediterranean-style eating, for instance, might be protective; that typically means a diet high in fish, vegetables and fruit, whole grains and unsaturated fats like those in olive oil.

The message is that eating a healthy, balanced diet in mid-life is important.

The relation of dietary choline to cognitive performance and white-matter hyperintensity in the Framingham Offspring Cohort. Am J Clin Nutr December 2011 vol. 94 no. 6 1584-159

B Vitamins Can Slow Cognitive Decline

This study found that people with mild cognitive impairment had their cognitive decline slowed by taking B vitamins. The modest doses used were easy to replicate. 800 mcg Folic Acid. 500 mcg B-12, 20 mg B-6 and they took them for two years.
Benefits seen? Significant improvements in homocysteine levels, in global cognition, episodic memory, delayed recall and semantic memory. Progression of memory impairment was slowed in the B vitamin group and not at all in the placebo group.

de Jager, Jacoby et al, 'Cognitive and clinical outcomes of homocysteine-lowering B-vitamin treatment in mild cognitive impairment: a randomized controlled trial', International Journal of Geriatric Psychiatry, 2011.

Taking a Multi-Vitamin May Boost Memory As We Age

Hope you're taking a multi every day!

In 1994, French researchers recruited 4,500 French men and women aged 45 to 60 to take part in the experiment.  Half of them took a daily supplement with vitamins C and E, selenium, zinc and beta-carotene for eight years, the other half took a placebo. The participants were not told whether they were taking the vitamin or the placebo.

After the eight years, researchers stopped giving participants the pills and gave them the choice of whether or not to take vitamin supplements. Six years later, the researchers brought them back for a round of memory tests, including word and number problems.

While the supplement and placebo groups performed similarly on most tests, the nutrient-boosted participants beat their peers on one test of long-term memory in which participants had to recall words in different categories.

The findings support a beneficial effect of a well-balanced intake of antioxidant nutrients at nutritional doses for maintaining cognitive performance, especially verbal memory.

Take a look at the study here.