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New research is published every day, but only some studies are big research stories or game-changers. The following are what I consider some of the most memorable studies of 2018 – some in a good way, but some of the others have left me with a sense of horror. I think there will be follow-up research, so keep an eye out for more on these important topics.

Are we heading toward a time in the not so distant future when all men are infertile? (Due to exposure to all the endocrine disruptors around us.) Will All Men Eventually Be Infertile? This was posted September 5, 2018.

Researchers are now seriously investigating and finding evidence that microbes may be causing Alzheimer’s disease. This approach is rapidly finding support in the medical field, and may lead to possible ways to treat or prevent the disease. Possible Herpes Virus Link to Alzheimer’s Disease was posted July 13, 2018, and Herpes Viruses and Alzheimer's Disease on  June 22, 2018.

Type 2 Diabetes May Be Reversed With Weight Loss was posted August 10, 2018. This study and an earlier similar study from 2016 found that losing over 30 pounds over a short period can reverse type 2 diabetes - 46% in the 2018 study and 60% (in people who had it less than 10 years) in the earlier study.

More and more evidence is accumulating that certain diets are anti-inflammatory. Especially beneficial are diets rich in fruits, vegetables, seeds, nuts, legumes (beans), and whole grains - which also have a lot of fiber. This is exciting research because chronic low-grade inflammation is linked to a number of chronic diseases (heart disease, cancer, etc.). Fruits, Vegetables, and Whole Grains Lower Inflammation – posted August 1, 2018.

[Related to this last topic is one of the most eye-opening studies I have ever read on how what one eats has a quick effect on gut microbes and health of the gut (including inflammation of the colon): Changing Diet Has Big Effect On Colon Cancer Risk – posted April 28, 2015.]

Another study finding more benefits of exercise was recently published in the journal Neurology. The study by researchers at Duke University found that in older adults who were already experiencing  cognitive (thinking) problems, but did not have dementia - that after just 6 months of exercise they showed improvements in thinking. What were their original thinking problems? The individuals had difficulty concentrating, making decisions, or remembering, but it was not severe enough to be diagnosed as dementia. However, these persons were considered at risk for progressing to dementia.

The 160 individuals in the study were 55 years or older (mean age 65), mainly women, evenly divided between whites and minorities, were sedentary (didn't exercise), and had heart (cardiovascular) disease or were at risk for heart disease. They were randomly assigned to one of 4 groups: 1) aerobic exercise (with no dietary changes), 2) DASH diet (with no exercise), 3) DASH diet plus exercise, and 4) the control group, who had no dietary or exercise changes - they just received some educational phone calls. The study lasted 6 months, and there were no drop outs.

In the study, the aerobic exercises were done 3 times per week: 10 minutes of warm up exercises followed by 35 minutes of continuous walking or stationary cycling. The Dietary Approaches to Stop Hypertension or DASH diet is a heart healthy diet that emphasizes eating fruits, vegetables, whole grains, as well as fish, poultry, beans, and nuts. It stresses lowering the intake of salt (sodium), sweets, sugar sweetened beverages, and fatty foods (both trans fats and saturated fats). [Note that in many ways it's similar to the Mediterranean diet with its emphasis on fruits, vegetables, whole grains, legumes, seeds, nuts, and lowering intake of meat. Studies find cognitive benefits from the Mediterranean diet.]

The six months of exercising improved thinking skills called executive function - in both the exercise alone or exercise + DASH diet group. The largest improvements were in the exercise + DASH diet group (as compared to the control group, which actually showed decline in functioning). Executive function is a person's ability to regulate their own behavior, pay attention, organize and achieve goals, and was measured in this study with a group of cognitive tests (a "standard battery of neurocognitive tests"). These executive function improvements did not occur in the DASH diet alone group or the control group. The study found no improvement in memory or language fluency in any of the groups. The exercise alone, DASH diet alone, and the combined exercise and DASH group had other health benefits by the end of the study, for example they lowered their risk factors for heart disease. Other improvements: the exercise groups had improvements in insulin levels, and the DASH groups decreased their intake of blood pressure medicines.

To illustrate how amazing these results are: at the start of the study (baseline) all participants scored as if they were in their early 90s on cognitive tests - as if they were on average about 28 years older than their actual chronological age! Then at the end of 6 months, the persons in the exercise + DASH diet showed an improvement of almost 9 years on the tests. In contrast, the control group showed an approximately 6 month worsening performance. When researchers looked at physical markers of the exercisers, they found that physical improvements and improvements in heart disease risk factors (e.g. losing weight, lowering blood pressure) were correlated with executive functioning improvements.

Other studies have found related findings, such as higher physical activity and a Mediterranean diet is associated with lower levels of dementia. The researchers point out that there is growing evidence that combining several lifestyle factors (e.g., exercise, not smoking, a healthy diet, lowering salt intake) and not just exercise alone, has the best results for better cognitive functioning among older adults. Bottom line: eat a diet rich in fruits, vegetables, whole grains, seeds, nuts and get exercise. Walking briskly, gardening, housework, walking up stairs - it all counts.  ...continue reading "Can Exercise and Dietary Changes Help Older Adults With Thinking Problems?"

A recent study adds to the list of health reasons to try to avoid type 2 diabetes if at all possible, such as making lifestyle changes (e.g. lose weight if overweight, improve diet,  exercise). Earlier studies found that the brain atrophies (decreases in volume) with type 2 diabetes, and that the presence of type 2 diabetes doubles the risk of dementia in older age. Yikes!

Similarly, Australian researchers in the recent study found that type 2 diabetes in older individuals is associated with decline in verbal memory and verbal fluency over a five year period, but the findings suggest that this may start in midlife.  This is because at the start of the study those with type 2 diabetes already showed signs of greater brain atrophy than those without type 2 diabetes. The type 2 diabetes group had "poorer cognitive function" at the start of the study, and then they continued to decline over the 5 year study time, but not at any greater rate than individuals without diabetes. In contrast to the decline in verbal fluency over the 5 year period in the diabetes group, the non-diabetes group actually showed an slight increase in verbal fluency each year.

Of the 705 persons in the study, the average age of the type 2 diabetes group was 68.2 years, while the non-diabetes group was 72.5 years - so can see that the diabetes group was generally younger. [Note that the brain shrinks a little as we age, and it's a normal part of aging, but you want to minimize it. The more "youthful" the brain, the better for cognitive functioning.

From Science Daily: In older people, type 2 diabetes is associated with a decline in brain function over 5 years, study shows

New research published in Diabetologia (the journal of the European Association for the Study of Diabetes [EASD]) shows that in older people living in the community, type 2 diabetes (T2D) is associated with a decline in verbal memory and fluency over 5 years ...continue reading "Type 2 Diabetes and the Brain"

Are bacteria living in healthy human brains? It has long been thought that the brain is protected by the blood-brain barrier, that the brain is sterile (bacteria are not normally there), and if there are bacteria in the brain, then that means a serious disease (e.g. meningitis).  However, the research team of Rosalind Roberts, Charlene Farmer, and Courtney Walker (at the University of Alabama) found bacteria in the brains they studied with electron microscopes.

The brains showed no inflammation (thus the bacteria were not pathogenic), and modern tests (genetic sequencing) showed that they were gut bacteria. Which  means they got there from the gut. If further research supports their findings, then this would be a paradigm shift -  a new way of thinking about the brain and microbes.

Two good articles discuss this research - the first is in Science, and the second is a fascinating interview of Rosalind Roberts about this research. Excerpts from the article written by Michael Segal in Nautilus:

Are There Bacteria in Your Brain?

...continue reading "Are Bacteria Living In Healthy Brains?"

Another reason to eat fruits and vegetables daily - cognitive and memory functioning in later life. A large US study of 27,842 men found that a higher intake of fruits, vegetables, and orange juice for many years is linked to a lower risk of poor cognitive functioning in later years of life (70s and beyond). The study specifically looked at subjective cognitive function - a measure of earliest changes in cognitive functioning, including memory. This is the stage before "mild cognitive impairment". The study started in 1986 when the average age was 51 years, and continued till 2012. The men studied were all health professionals (e.g. dentists)

What was a high intake of fruits and vegetables? For vegetables: about 5.7 servings per day (while the lowest intake was 1.7 servings per day). For fruit: high intake was 3.1 servings per day (vs lowest intake was .5 servings per day). For fruit juice (orange juice): high intake was 1.5 servings per day (vs lowest intake was .1 servings per day). A serving of fruit is considered one cup of fruit or ½ cup of fruit juice. A serving of vegetables is considered one cup of raw vegetables or two cups of leafy greens.

The researchers found that green leafy vegetables, carotenoid-rich vegetables (esp. tomatoes and peppers), cantalope, berries, and orange juice to be especially protective. They point out that many antioxidant nutrients and bioactive substances (including vitamins A,B, C, and E, carotenoids, flavonoids, and polyphenols) are all found naturally in vegetables, fruits, and juices. These are thought to reduce brain oxidative stress, improve cognitive performance, and to prevent neuronal damage. In other words, all good things for the brain. From Science Daily:

Orange juice, leafy greens and berries may be tied to decreased memory loss in men

Eating leafy greens, dark orange and red vegetables and berry fruits, and drinking orange juice may be associated with a lower risk of memory loss over time in men, according to a study published in the November 21, 2018, online issue of Neurology, the medical journal of the American Academy of Neurology.  ...continue reading "Eat Fruits And Vegetables Every Day!"

A benefit (perhaps) of having the appendix taken out in childhood - it is associated with a lower rate of Parkinson's disease decades later in life, according to an international study that looked at health records of 1.7 million people in Sweden. Other main findings is that this finding is especially strong for individuals living in rural areas (and not urban areas), and that removing the appendix also delayed the age of Parkinson's disease onset in those who got the disease. But if you read further, there were other interesting findings in the study, even though much is still unknown - it's still a big puzzle with lots of pieces still to be filled in.

By the way, other recent research also supports the view that Parkinson's disease gets its start in the gut - and not in the brain, which is what everyone thought for years. But note that there are other risk factors such as certain pesticide exposure or drug use, or trauma to the head that are linked to Parkinson's disease. Many studies find that rural living is associated with a higher risk for Parkinson's disease, and it is thought this is probably due to higher exposure to pesticides, which then somehow contributes to the development of Parkinson's disease. From Medical Xpress:

Appendix removal is linked to lower risk of Parkinson's

Scientists have found a new clue that Parkinson's disease may get its start not in the brain but in the gut—maybe in the appendix. People who had their appendix removed early in life had a lower risk of getting the tremor-inducing brain disease decades later, researchers reported Wednesday.

Why? A peek at surgically removed appendix tissue shows this tiny organ, often considered useless, seems to be a storage depot for an abnormal protein—one that, if it somehow makes its way into the brain, becomes a hallmark of Parkinson's ...continue reading "Appendix Removal and Parkinson’s Disease"

Do you have a good sense of smell and are also good at navigation? A series of studies by Canadian researchers found that they are linked - and that these abilities are located in overlapping brain areas - the orbitofrontal cortex and hippocampus. The Canadian researchers found that both the cortical thickness of the left orbitofrontal cortex and the right hippocampus were bigger in the better smellers and better navigators (the subjects had MRI scans).

The researchers say the findings support the view that olfaction (the sense of smell) evolved to aid navigation - this hypothesis is called the olfactory spatial hypothesis. For example, all animals use chemical cues to navigate, to find food, to avoid being preyed upon, while in contrast vision and hearing are not present in all animals. In humans, good navigators have what the researchers call "spatial memory". From Laura Sanders at Science News:

People who have a good sense of smell are also good navigators ...continue reading "Are You Both A Good Navigator And Have A Good Sense of Smell?"

So many of us seem to not get enough sleep, and then there are those that sleep and sleep. But .. it seems the sweet spot for sleep and our brain health (cognitive performance) is about 7 to 8 hours - at least according to a large study from Canadian researchers at Western University. People reporting typically sleeping 4 hours or less a night had the most impairments in how they performed on a variety of cognitive tests - equivalent to aging 8 years.

Reasoning, verbal skills, and overall cognition were impaired by less than 7 hours or more than 8 hours of sleep. But not short term memory. Actual age of the person made no difference on the results - everyone performed best at 7 to 8 hours of sleep. (Volunteers completed a series of 12 tests online which measured a broad range of cognitive abilities.) By the way, about half of the 10886 persons participating in the study reported typically sleeping 6.3 hours or less a night. Not enough. The good news is that just one night of sleeping a little more than the usual too little had a positive effect on cognitive abilities - thus cognitive improvement. From Science Daily:

World's largest sleep study shows too much shut-eye can be bad for your brain  ...continue reading "What Is Optimal Amount Of Sleep For Our Cognitive Processes?"

The results of a recent study suggested that walking 4 hours or more a week or 2 to 3 hours of moderate physical activity may have a (slight) protective effect of reducing stroke severity in persons who get a stroke. The study, which was conducted in Sweden, found that persons who were physically more active before their stroke and were younger in age were more likely to have a mild stroke (rather than a moderate or severe stroke). This finding was an association (didn't prove it).

But ...the majority of persons participating in the study - whether they exercised or not before the stroke - had mild strokes, and a minority in all of the groups had moderate or severe strokes. 73% of physically inactive people, 85% of those with light physical activity, and 89% of  those who had engaged in moderate physical activity before their strokes had mild strokesResearchers found that light (walking or a similar activity for at least 4 hours per week) and moderate physical activity (2 to 3 hours per week) were equally beneficial. From Medical Xpress:

People who walk just 35 minutes a day may have less severe strokes

People who participate in light to moderate physical activity, such as walking at least four hours a week or swimming two to three hours a week, may have less severe strokes than people who are physically inactive, according to a study published in the September 19, 2018, online issue of Neurology, the medical journal of the American Academy of Neurology. 

...continue reading "Could Physical Activity Reduce Stroke Severity?"

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Nice study that explains why sitting for long periods is so unhealthy - it reduces blood flow to the brain (cerebral blood flow) . The results from a study conducted in the United Kingdom (UK) found that prolonged, uninterrupted sitting (4 hours in the study) in healthy office workers reduced cerebral blood flow. However this was offset when frequent, short-duration walking breaks were taken - about 2 minutes of walking every 30 minutes. However, taking a 8 minute walking break every 2 hours did not have the same positive effect - even though that was the same amount of walking over the 4 hour period.

Maintaining good blood flow to the brain is a great reason to stretch your legs and walk a few minutes whenever possible, preferably at least every 30 minutes - whether at work or at home. From Medical Xpress:

Sitting for long hours found to reduce blood flow to the brain

A team of researchers with Liverpool John Moores University in the U.K. has found evidence of reduced blood flow to the brain in people who sit for long periods of time. In their paper published in the Journal of Applied Physiology, the group outlines the experiments they carried out with volunteers and what they found.  ...continue reading "Sitting For Long Periods and Reduced Blood Flow To the Brain"