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Category: healthy aging

Published on Leave a comment on Blueberries and the Aging Brain

A new study was published that supports eating lots of blueberries (or drinking blueberry juice) for health - this time better brain functioning in people aged 65 to 77 who drank concentrated blueberry juice daily for 12 weeks. The people randomly assigned to the group drinking blueberry juice daily showed improvements in cognitive function, blood flow to the brain, and activation of the brain while carrying out cognitive tests. The people received MRIs (magnetic resonance imaging), as well as various blood tests and cognitive tests.

And how much did they drink of the juice daily? Thirty ml or 1 ounce of blueberry concentrate (which provided 387 mg anthocyanins) which was diluted with tap water. Anthocyanins are anti-oxidants that belong to a class of compounds called flavonoids, and are found in high concentrations in blueberries, cherries, and plums. The blueberry concentrate amount was equivalent to about 230 grams of blueberries - about 1 1/3 cups blueberries.

What was good about the study was that to eliminate bias people were both randomly assigned to the blueberry juice group or a placebo group (they drank a synthetic fruit cordial) - and it was "double-blind" so that no one knew who was in which group. Interestingly, people who were already eating more than 5 portions of fruits daily were excluded from the study - because so many other studies have already found all sorts of brain benefits from a diet with lots of fruits and berries. But the main conclusion from this and other related research is: eating lots of berries is good for you and has health benefits. From Medical Xpress:

Blueberry concentrate improves brain function in older people

Drinking concentrated blueberry juice improves brain function in older people, according to research by the University of Exeter. In the study, healthy people aged 65-77 who drank concentrated blueberry juice every day showed improvements in cognitive function, blood flow to the brain and activation of the brain while carrying out cognitive tests. There was also evidence suggesting improvement in working memory. Blueberries are rich in flavonoids, which possess antioxidant and anti-inflammatory properties.

Of the 26 healthy adults in the study, 12 were given concentrated blueberry juice - providing the equivalent of 230 g of blueberries - once a day, while 14 received a placebo. Before and after the 12-week period, participants took a range of cognitive tests while an MRI scanner monitored their brain function and resting brain blood flow was measured. Compared to the placebo group, those who took the blueberry supplement showed significant increases in brain activity in brain areas related to the tests. The study excluded anyone who said they consumed more than five portions of fruit and vegetables per day, and all participants were told to stick to their normal diet throughout. [Original study.]

Published on Leave a comment on Ten Portions of Fruits and Vegetables Daily?

 This past week a study was published linking 8 to 10 portions of fruits and vegetables per day with a lower risk of early death, cancer, heart disease, and stroke. This confirms other research linking many daily servings of fruits and vegetables with various health benefits. For example, the study findings discussed in the Nov. 2, 2016 post: "Eating lots of fruits and vegetables (more than 10 servings a day!)  is linked to better cognitive functioning in both normal weight and overweight adults (both young and older adults), and may delay the onset of cognitive decline that occurs with aging and also dementia."

This new study led by researchers from the Imperial College London reviewed 95 previous studies of the relationship between diet and health. They found that people who ate 10 portions of fruits and vegetables a day had nearly a third lower risk of premature death and stroke than those who ate very little or no fruits and vegetables. The researchers pointed out that as the amount of fruits and vegetables eaten daily went up, the health benefits also increased (lower risk of heart disease, stroke, cardiovascular disease, cancer), and the risk of premature death decreased - thus a dose related relationship. So better to eat some fruits and vegetables than none! A portion is about 80 grams, equivalent to a medium apple, 1 banana, or generally about 1/2 cup of vegetables or fruits.

From Science Daily: Eating up to ten portions of fruit and vegetables a day may prevent 7.8 million premature deaths worldwide

A fruit and vegetable intake above five-a-day shows major benefit in reducing the chance of heart attack, stroke, cancer and early death. This is the finding of new research, led by scientists from Imperial College London, which analysed 95 studies on fruit and vegetable intake....the greatest benefit came from eating 800 g a day (roughly equivalent to ten portions -- one portion of fruit or vegetables if defined as 80 g).

The results revealed that even a daily intake of 200 g was associated with a 16 per cent reduced risk of heart disease, an 18 per cent reduced risk of stroke, and a 13 per cent reduced risk of cardiovascular disease. This amount, which is equivalent to two and a half portions, was also associated with 4 per cent reduced risk in cancer risk, and 15 per cent reduction in the risk of premature death. Further benefits were observed with higher intakes. Eating up to 800 g fruit and vegetables a day -- or 10 portions -- was associated with a 24 per cent reduced risk of heart disease, a 33 per cent reduced risk of stroke, a 28 per cent reduced risk of cardiovascular disease, a 13 per cent reduced risk of total cancer, and a 31 per cent reduction in dying prematurely. This risk was calculated in comparison to not eating any fruit and vegetables. [Original study.]

Published on Leave a comment on Health Benefits of 5 Days of Calorie Restriction

Do you want to live longer and be healthy at the same time? Some possible ways may be to restrict the calories in the diet (every day) or to practice intermittent calorie restriction (a fasting mimicking diet a few days a month or even each week, such as the 5:2 diet). Previous studies in animals and humans have suggested that periodic fasting can reduce body fat, cut insulin levels, and provide other benefits. Studies in animals found that sharply restricting calories (calorie restriction or CR) daily resulted in longer, healthier lives, but it is unknown if the benefits of chronic calorie restriction also holds true for humans, and even if it might be dangerous. And really - how many people would actually want to reduce their calorie intake by 25% or more day in and day out for years? Intermittent calorie restriction seems much, much easier.

Two recently published studies suggest health benefits of calorie restriction diets - chronic calorie restriction in adult rhesus monkeys, and intermittent calorie restriction (a fasting mimicking diet a few days a month) in humans.

Researchers at the Univ. of Wisconsin–Madison and National Institute of Aging reanalyzed two studies they had originally done with conflicting results, and now they reported in Nature Communications that chronic calorie restriction produced health benefits (such as lower incidence of cancer, cardiovascular problems) and longer life in rhesus monkeys. Since these primates have human-like aging patterns, they thought that CR would also have similar benefits in humans - a longer, healthier life.  The researchers describe one monkey they started on a 30 percent calorie restriction diet when he was 16 years old (late middle age for rhesus monkeys), and that he is now 43 (a longevity record for the species). They found that in nonhuman primates calorie restriction is beneficial when started in adulthood (especially late middle age in males), but does not improve survival when started in juveniles (young animals) - and in fact they tended to die at an earlier age than the normal diet group of primates.

In the other study (in Science Translational Medicine), research suggests it is possible to gain anti-aging benefits with a “fasting-mimicking diet,” practiced just five days a month. 100 healthy adults (aged 20 to 70) were randomly assigned to either a group following a low-calorie "fasting-mimicking" diet (FMD) five days a month, for 3 months, or a normal diet control group. After 3 months, the control group also went on the fasting mimicking diet. Test subjects followed a 50 percent calorie restricted diet (totaling about 1,100 calories on the first day) and 70 percent diet (about 700 calories) on the next four days, then ate whatever they wanted for the rest of the month. The calorie-restricted diet was low in calories, sugars, and protein, was 100 percent plant-based, and featured vegetable soups, energy bars, energy drinks, and a chip snack, as well as mineral and vitamin supplements. (Note that Longo and Univ. of Southern California are both owners of L-Nutra, the company that manufactures the diet. But Longo says he takes no salary or consulting fees from the company.)

But it still wasn't easy for the test subjects to follow the 5 days of restricted calories per month because there was a 25% drop out rate. Health benefits (about a 6 pound weight loss, smaller waistlines, lower blood pressure, lower levels of inflammation, and better levels of glucose, triglycerides and cholesterol, etc.), showed up after the third month and persisted for at least three months—even after subjects had returned full-time to a normal diet. They lost body fat, but lean muscle mass remained unchanged. They found that the benefits were greater for people who were obese or otherwise unhealthy. In summary, the researchers said that 3 cycles of the 5 days per month of fasting-mimicking diet improved the levels of a variety of "markers/risk factors associated with poor health and aging and with multiple age-related diseases" (such as cancer, diabetes, heart disease, etc).

Other researchers say there is no need to suffer through such extreme diets, but to instead follow a healthy lifestyle, which includes a healthy diet (with lots of vegetables, fruits, legumes, seeds, whole grains, and nuts), and to exercise. And remember - nowhere does following restricted calorie diets mean you'll live longer - just that you should be healthier as you age (hopefully). There are no guarantees in life...

From Science Translational Medicine: Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular disease

Mice that fast periodically are healthier, metabolically speaking. To explore whether fasting can help people as well, Wei et al. studied 71 people who either consumed a fasting-mimicking diet for 5 days each month for 3 months or maintained their normal diet for 3 months and then switched to the fasting schedule. The fasting-like diet reduced body weight and body fat, lowered blood pressure, and decreased the hormone IGF-1, which has been implicated in aging and disease. A post hoc analysis replicated these results and also showed that fasting decreased BMI, glucose, triglycerides, cholesterol, and C-reactive protein (a marker for inflammation). These effects were generally larger in the subjects who were at greater risk of disease at the start of the study. A larger study is needed to replicate these results, but they raise the possibility that fasting may be a practical road to a healthy metabolic system.

From Nature Communications:  Caloric restriction improves health and survival of rhesus monkeys

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Published on 5 Comments on Vitamin B3 and Glaucoma

Image result for eyes A recent study had great results in preventing glaucoma or stopping the progress of glaucoma by supplementing the diet of mice with vitamin B3 (nicotinamide). But now the research needs to see if this also holds true for humans.

Glaucoma is a common neurodegenerative disease that results in vision loss. Two main risk factors are increasing age and high intraocular pressure (pressure in the eye). The researchers said that their next step is testing B3 in human glaucoma patients. So stay tuned...

Vitamin B3, also known as niacin, is an essential vitamin for health, but both deficiencies and too high doses have negative health effects. It is recommended that adults get between 14 mg to 18 mg of niacin per day. Since it is not stored in the body (the excess will be excreted in urine), then you need to get a continuous supply from your diet.

As seen in so many other studies of vitamins and minerals, there is no evidence of adverse effects from the consumption of naturally occurring niacin in foods, but one can get too much from supplements (along with negative health effects).

What foods are good sources of B3 (niacin)? Foods highest in B3 (niacin) are tuna, chicken, turkey, but other good sources are anchovies, salmon, sardines, red meat, peanuts, nuts, seeds, eggs, mushrooms, dairy foods. lentils, beans, potatoes, and grain products.

From Medical Xpress: Vitamin B3 prevents glaucoma in laboratory mice

In mice genetically predisposed to glaucoma, vitamin B3 added to drinking water is effective at preventing the disease, a research team led by Jackson Laboratory Professor and Howard Hughes Medical Investigator Simon W.M. John reports in the journal Science. ...continue reading "Vitamin B3 and Glaucoma"

Published on Leave a comment on Older Adults, Exercise, and the Brain

 Once again, research supports that you should get off your butt and exercise! Or do a moderate to vigorous physical activity at least several times a week, which can include housework, gardening, dancing, swimming, or walking briskly. Most important is to MOVE. And why is this so important? Not just for physical health and prevention of certain diseases, but also for the health of your brain, especially as it ages.

The research looked at both 31 young healthy adults (18 to 31 years old) and 26 older healthy adults (55 to 74 years old), assessed their cardiorespiratory (heart/lung) fitness on the treadmill, gave them a number of neurological tests, and also a memory task while their brain activity was observed during functional Magnetic Resonance Imaging (fMRI). They found that the older adults with higher heart/lung fitness had better performance on the memory task and greater brain activity in multiple regions than the older adults with low heart/lung fitness. The increased brain activity in those with higher levels of heart/lung fitness occurred in brain regions typically affected by age-related decline - in other words, higher fitness in older adults reduced some age-related differences.

The researchers thought these and other study results indicate that heart/lung fitness (cardiorespiratory fitness) may keep the brain younger (that is, it preserves neurological function and "neuroplasticity") as people age. They pointed out that some recent studies have revealed that lower cardiorespiratory (heart/lung) fitness was associated with accelerated cognitive decline and that older adults with lower heart/lung fitness had an increased risk for dementia.

From Health Day: Fitter Seniors May Have Healthier Brains

Good heart and lung fitness can benefit older adults' brains, researchers report.They assessed the heart/lung fitness of healthy young adults (aged 18 to 31) and older adults (aged 55 to 74), and compared their ability to learn and remember the names of strangers in photos. MRI scans recorded images of their brain activity as they learned the names.

The older adults had more difficulty with the memory test than the young adults. But older adults with high levels of heart/lung fitness did better on the test and showed more brain activity when learning new names than those of their peers with lower levels of heart/lung fitness. The increased brain activity in those with higher levels of heart/lung fitness occurred in regions typically affected by age-related decline. The findings suggest that heart/lung fitness may also help keep the brain healthy as people get older, according to the researchers. But the study did not prove a cause-and-effect link.

"Importantly, [heart/lung fitness] is a modifiable health factor that can be improved through regular engagement in moderate to vigorous sustained physical activity such as walking, jogging, swimming or dancing," said study corresponding author Scott Hayes....The researchers said high levels of fitness will not prevent brain decline, but may slow it.

An excerpt from the original study, from Cortex: FMRI activity during associative encoding is correlated with cardiorespiratory fitness and source memory performance in older adults

For brain regions in which older adults showed reduced activation relative to young adults, including left inferior frontal gyrus, medial frontal gyrus, bilateral thalamus, and fusiform gyrus, we observed a step-wise pattern, with the greatest activation in young adults, followed by high CRF [cardiorespiratory fitness] older adults and then low CRF older adults, indicating that higher fitness in older adults reduced age-related differences. These findings suggest that CRF supports successful brain maintenance in aging, in that it promotes the preservation of neural function seen in young adults (Nyberg, Lovden et al., 2012). 

Published on Leave a comment on Air Pollution, the Aging Brain, and Dementia

Another study finding a link between air pollution and negative health effects - this time a higher incidence of decline in cognitive functioning  and dementia in older women (65 and older) exposed to fine particles (PM2.5 ). These extremely small particles from vehicle emissions are a major source of urban air pollution throughout the world. These results match other studies finding a link with urban air pollution, especially vehicle traffic, to negative effects on the brain (dementia, cognitive decline, shrinking of the brain, etc.). The researchers also exposed mice to this air pollution for 15 weeks and then studied their brains for evidence of degenerative effects in their brains - and yes, they did find them.

The researchers found that the adverse effects of fine particulate air pollution was stronger in both women and mice who had the APOE4 gene, a genetic variation that increases the risk for Alzheimer's disease. They said that while the air pollution has negative effects in general, that having the APOE4 gene interacted with the air pollution. The researchers also wrote that the mice studies they did showed that "...exposure to urban airborne particulates can intensify amyloid accumulation and neurodegeneration". Medical Xpress:

Air pollution may lead to dementia in older women

Tiny air pollution particles—the type that mainly comes from power plants and automobiles—may greatly increase the chance of dementia, including Alzheimer's disease, according to USC-led research. Scientists and engineers found that older women who live in places with fine particulate matter exceeding the U.S. Environmental Protection Agency's standard are 81 percent more at risk for global cognitive decline and 92 percent more likely to develop dementia, including Alzheimer's.

If their findings hold up in the general population, air pollution could be responsible for about 21 percent of dementia cases, according to the study. "Microscopic particles generated by fossil fuels get into our body directly through the nose into the brain," said University Professor Caleb Finch at the USC Leonard Davis School of Gerontology and co-senior author of the study. "Cells in the brain treat these particles as invaders and react with inflammatory responses, which over the course of time, appear to exacerbate and promote Alzheimer's disease.

The adverse effects were stronger in women who had the APOE4 gene, a genetic variation that increases the risk for Alzheimer's. "Our study .....provides the inaugural scientific evidence of a critical Alzheimer's risk gene possibly interacting with air particles to accelerate brain aging," said Jiu-Chiuan Chen, co-senior author of the study....[Their study] adds to an emerging body of research from around the world that links air pollution to dementia. The offending pollutants—known as PM2.5—are fine, inhalable particles with diameters 2.5 micrometers or smaller. A human hair is about 70 micrometers in diameter, making it 30 times larger than the largest PM2.5. The researchers analyzed data of 3,647 65- to 79-year-old women from the Women's Health Initiative Memory Study (WHIMS). These women lived across 48 states and did not have dementia when they enrolled.

USC scientists chronically exposed female mice carrying the APOE4 gene to nano-sized air pollution for 15 weeks. Compared to the control group, mice predisposed to Alzheimer's disease accumulated as much as 60 percent more amyloid plaque, the toxic clusters of protein fragments that further the progression of Alzheimer's.

In other studies, Chen and his colleagues linked long-term exposure to high PM2.5 levels to smaller gray and white matter volumes in important areas such as the frontal lobe, which carries out thinking, decision-making and planning. For every 3.5 micrograms of PM2.5 per cubic meter of air, white matter (insulated nerve fibers that connect different brain regions) decreased by 6 cubic centimeters, according to one earlier study. [see post]

Published on Leave a comment on Exercising Just On Weekends Has Health Benefits

Worried about whether being physically active just on weekends can make a difference in health if the rest of the week is spent sitting all day? Well, there is good news! Being a "weekend warrior" (one who exercises or is active only one or two days a week) may also offer health benefits according to a new study (associated with lower death rates from all causes, cancer, and cardiovascular disease).

Current government guidelines recommend at least 150 minutes per week of moderate-intensity activity (such as brisk walking or tennis), or at least 75 minutes per week of vigorous activity (such as jogging or swimming laps), or equivalent combinations of moderate and vigorous physical activity. From Science Daily:

'Weekend warriors' have lower risk of death from cancer, cardiovascular disease

Physical activity patterns characterized by just one or two sessions a week may be enough to reduce deaths in men and women from all causes, cardiovascular disease (CVD) and cancer, regardless of adherence to physical activity guidelines, a new study of over 63,000 adults reports. The finding suggests that less frequent bouts of activity, which might fit more easily into a busy lifestyle, offer significant health benefits, even in the obese and those with medical risk factors.

Regular physical activity is associated with lower risks of death from all causes, cardiovascular disease and cancer, and has long been recommended to control weight, cholesterol, and blood pressure. The World Health Organization recommends that adults do at least 150 minutes per week of moderate-intensity activity, or at least 75 minutes per week of vigorous-intensity activity, or equivalent combinations.

But research is yet to establish how the frequency and total weekly dose of activity might best be combined to achieve health benefits. For example, individuals could meet current guidelines by doing 30 minutes of moderate-intensity physical activity five days of the week or 75 minutes of vigorous-intensity physical activity on just one day of the week. Those who do all their exercise on one or two days of the week are known as 'weekend warriors'. 

Published on Leave a comment on Why Do Some Older Adults Have Youthful Brains?

The beginning of a new year is a time to think about the future, and perhaps think about healthy lifestyles and how to age well. One important issue to think about is: why do some older people have "young" minds while others do not? Can anything be done to improve our odds later in life of being a "superager" and having a youthful, sharp, clear mind?

Unfortunately, as humans age, memory and many other cognitive functions often decline. “Normal” performance on various cognitive tests may be substantially lower than that of a younger adult, but... there is substantial variation in the degree of cognitive decline with age. Some older adults—referred to by some as “superagers”—continue to perform mentally at a level similar to middle-aged adults and sometimes even young adults.

Earlier posts have examined some of the things that help people age well and keep their brains more "youthful" - from diet (here, here, and here), to daily coffee consumption, vitamin D levels (here and here), regular physical activity and exercise (here, here, and here), not living in polluted areas (here and here), civic engagement, higher education, learning new skills, doing arts or crafts, and using a computer (here). Also frequently mentioned are social activities, intellectual stimulation, and genetics.

One recent study (discussed below) found that doing something hard and really challenging (that means forget pleasant puzzles), something that tires you out (whether physically or mentally) is what is good for the brain. So go out and learn a new language or musical instrument, sign up for a course, or anything else that is really challenging - whether physical or mental. Excerpts from a piece written by Lisa F. Barrett, a professor of psychology at Northeastern University, from the NY Times:

How to Become a ‘Superager’

Think about the people in your life who are 65 or older. Some of them are experiencing the usual mental difficulties of old age, like forgetfulness or a dwindling attention span. Yet others somehow manage to remain mentally sharp....Why do some older people remain mentally nimble while others decline? “Superagers” (a term coined by the neurologist Marsel Mesulam) are those whose memory and attention isn’t merely above average for their age, but is actually on par with healthy, active 25-year-olds. My colleagues and I at Massachusetts General Hospital recently studied superagers to understand what made them tick.

Our lab used functional magnetic resonance imaging to scan and compare the brains of 17 superagers with those of other people of similar age. We succeeded in identifying a set of brain regions that distinguished the two groups. These regions were thinner for regular agers, a result of age-related atrophy, but in superagers they were indistinguishable from those of young adults, seemingly untouched by the ravages of time...... The thicker these regions of cortex are, the better a person’s performance on tests of memory and attention, such as memorizing a list of nouns and recalling it 20 minutes later.

Of course, the big question is: How do you become a superager? Which activities, if any, will increase your chances of remaining mentally sharp into old age? We’re still studying this question, but our best answer at the moment is: work hard at something. Many labs have observed that these critical brain regions increase in activity when people perform difficult tasks, whether the effort is physical or mental. You can therefore help keep these regions thick and healthy through vigorous exercise and bouts of strenuous mental effort. My father-in-law, for example, swims every day and plays tournament bridge.

The road to superaging is difficult, though, because these brain regions have another intriguing property: When they increase in activity, you tend to feel pretty bad — tired, stymied, frustrated. Think about the last time you grappled with a math problem or pushed yourself to your physical limits. Hard work makes you feel bad in the moment. The Marine Corps has a motto that embodies this principle: “Pain is weakness leaving the body.” That is, the discomfort of exertion means you’re building muscle and discipline. Superagers are like Marines: They excel at pushing past the temporary unpleasantness of intense effort. Studies suggest that the result is a more youthful brain that helps maintain a sharper memory and a greater ability to pay attention.

This means that pleasant puzzles like Sudoku are not enough to provide the benefits of superaging. Neither are the popular diversions of various “brain game” websites. You must expend enough effort that you feel some “yuck.” Do it till it hurts, and then a bit more.

In the United States, we are obsessed with happiness. But as people get older, research shows, they cultivate happiness by avoiding unpleasant situations. This is sometimes a good idea, as when you avoid a rude neighbor. But if people consistently sidestep the discomfort of mental effort or physical exertion, this restraint can be detrimental to the brain. All brain tissue gets thinner from disuse. If you don’t use it, you lose it. So, make a New Year’s resolution to take up a challenging activity. Learn a foreign language. Take an online college course. Master a musical instrument. Work that brain. Make it a year to remember. [Original study]

Published on Leave a comment on Focus On Healthy Lifestyle, Not Just On Tests And Screenings

The wonderful blog posts of Dr. John Mandrola (physician, blogger, and columnist at Medscape) are always thoughtful, and this latest points out things a number of studies have pointed out for a while. Which is to stop obsessing or focusing on "preventive tests" and screenings and numbers, and instead focus on a healthy lifestyle - which means getting regular exercise or physical activity, don't smoke cigarettes, maintaining a healthy weight, and eating a healthy diet with lots of fruits, vegetables, nuts, seeds, whole grains, and legumes (think Mediterranean-style diet).

Don't want overdiagnosis and overtreatment (here, here, here, and here). Excerpts from Dr. John M:

I am changing…

The main thing that has changed about me is my views as a doctor, especially when it comes to dealing with people who complain of nothing. Medicine is most pure when we treat people with illness. The infirmed come to us with a problem and we use our intelligence, experience and procedural skills to help them. It’s immensely gratifying. The joy of helping people still negates the stifling burden of administrative nonsense. I’ll do your damn corporate safety modules one more year because helping sick people get well feels so good.

But when people complain of nothing, our first job is to do no harm. I know prevention of disease is better than treating it, but the process of prevention gets dicey. When we prescribe things (screening tests, statins, aspirin, diabetes drugs etc) to people who complain of nothing, we should have the highest evidence these therapies deliver benefit. Too often, we cite eminence rather than evidence.

I’ve come to believe the medical profession is too paternalistic, too arrogant. I fear the medicalization of the human condition. These days, I order fewer tests. Medical tests put people into the “system,” on the metaphorical train of healthcare. This train accelerates quickly, and it’s often hard to get off. Even a simple echo scares me. I could tell you stories.

More often than not, I tell patients to stop checking their “numbers.” If they insist on health numbers, I favor three–the scale, the belt size and a Timex to measure walking speed.

A 2002 article from Dr. David Sackett (a pioneer of evidence-based medicine) perfectly captures my views on preventive medicine. It’s called The Arrogance of Preventive Medicine. It’s worth a look, now more than ever.

Published on Leave a comment on Loss of Smell And Alzheimer’s Disease

Recently some studies have found that a diminished sense of smell occurs in persons with mild cognitive impairment and Alzheimer's disease. Doctors have long observed that patients with Alzheimer's frequently complain that food doesn't taste good anymore (because they can't smell what they are eating). This is because odor signals from the nose are processed in areas of the brain that are among the first to be affected by Alzheimer's disease. It is thought that as dementia starts and progresses, the parts of the brain that distinguish odors start to deteriorate.

This is why various odor tests have been devised. One such odor test (used in the following study) is called "Sniffin Sticks", which tests for 16 odors such as orange, peppermint, leather, banana, garlic, rose, fish, and coffee. However, note that other degenerative brain diseases (including Parkinson's) can also affect odor detection, and the ability to smell can be diminished by smoking, certain head injuries, and even normal aging. From Medical Xpress:

Study confirms 'sniff test' may be useful in diagnosing early Alzheimer's disease

Tests that measure the sense of smell may soon become common in neurologists' offices. Scientists have been finding increasing evidence that the sense of smell declines sharply in the early stages of Alzheimer's, and now a new study from the Perelman School of Medicine at the University of Pennsylvania published today in the Journal of Alzheimer's Disease confirms that administering a simple "sniff test" can enhance the accuracy of diagnosing this dreaded disease. The sniff test also appears to be useful for diagnosing a pre-dementia condition called mild cognitive impairment (MCI), which often progresses to Alzheimer's dementia within a few years.

Roalf and his colleagues used a simple, commercially available test known as the Sniffin' Sticks Odor Identification Test, in which subjects must try to identify 16 different odors. They administered the sniff test, and a standard cognitive test (the Montreal Cognitive Assessment), to 728 elderly people. The subjects had already been evaluated by doctors at Penn with an array of neurological methods, and according to expert consensus had been placed in one of three categories: "healthy older adult," "mild cognitive impairment," or "Alzheimer's dementia." Roalf and his team used the results from the cognitive test alone, or combined with the sniff test, to see how well they identified subjects in each category.

As researchers report, the sniff test added significantly to diagnostic accuracy when combined with the cognitive test. For example, the cognitive test alone correctly classified only 75 percent of people with MCI, but that figure rose to 87 percent when the sniff test results were added. Combining the two tests also enabled more accurate identification of healthy older adults and those with Alzheimer's dementia. The combination even boosted accuracy in assigning people to milder or more advanced categories of MCI.

Prompted by prior studies that have linked a weakening sense of smell to Alzheimer's, doctors in a few larger dementia clinics already have begun to use smell tests in their assessments of elderly patients. Part of the reason the practice has not yet become common is that the tests that seem most useful take too long to administer.