Monday, January 7, 2019

We Evolved to Exercise

The January, 2019, issue of Scientific American has a great story by Herman Pontzer about how we humans are similar and profoundly different from our cousins –chimpanzees, bonobos, orangutans and gorillas  - with whom we share over 97% of our DNA.  Herman Ponzer is a professor of evolutionary anthropology at Duke University, who has studied hunter gathering humans and apes for many years.  Apes remain healthy at low activity levels, often spending 8-10 hours a day resting, grooming and eating before going to sleep for 9-10 hours. They remain remarkably healthy and lean at these low levels of physical activity, with very little heart disease or diabetes, even in captivity.  

For us human, however, it’s a different story.  We split from chimpanzees and bonobos about 6-7 million years ago.  Recent findings indicate that we gradually became fully upright, walking creatures who could still get up into the trees.  About 1.8 million years ago we began to develop stone tools for butchering animals, indicating that we probably ran them down. At the same time we expanded out of Africa into Eurasia and as far as Indonesia.  The ability to hunt as well as gather was the key.  Relying on meat requires cooperation and sharing. It is thought that these early humans got roughly half their calories from plants and half from meat.  Hunter-gatherers typically walked 12,000 to 18,000 steps a day. 

Our physiology has changed and adapted to this active life.  The brain has evolved to need less sleep – about 7 hours, far less than the apes. Our brain has also evolved to reward prolonged exercise, producing endocannabinoids.  Exercise enables the expansion of the brain in childhood and adulthood, and is known to improve memory.  Our leg muscles are 50% bigger than those in other apes, and we have more red blood cells to carry oxygen to our working muscles.  You can understand that our bodies have evolved to requiredaily physical activity. Exercising muscles release hundreds of signaling molecules.  They reduce chronic inflammation, and lower levels of testosterone, estrogen and progesterone.  This may account for the reduced rate of reproductive cancers among those who exercise regularly.  The morning rise of cortisol is blunted, which may mitigate stress.  Exercise reduces insulin insensitivity and helps to put glucose into muscle glycogen instead of fat.  Diabetes is thus prevented.  Exercise improves the ability of the immune system to stave off infection. Even light activity, such as standing instead of sitting, is helpful.  

Another article in the January Scientific American concerns a genetic mutation that may have occurred in our species 2-3 million years ago, enabling humans to run long distances, sweat to cool off, and hunt their prey to exhaustion.  Biologist Ajit, Varki at UC San Diego is studying this hypothesis. 

The take-home message from these studies is that we have evolved to move – a lot more than most of us are accustomed to.  To stay healthy as we grow from childhood into old age, we need to stay active. This will take social planning – to make more sidewalks, playgrounds and parks in many towns and cities, and keep them safe.  Children of all ages need places to get outside and play.  They may also do sports, skateboard, bicycle, run with a dog, swim or dance. 

 It will take individual planning to bring activity into our adult  lives despite sedentary desk jobs and the pull of screen time.  We can sign up for Yoga, Pilates and walking groups. We can join a gym. I have a sturdy floor bicycle called a Desk Cycle, so while I watch Rachel Maddow or read a book at least I’m moving my legs.  It can fit under a desk.  There are lots of other home exercise machines. Housework counts!  People who are on their feet all day in restaurants and stores still need to think about weekend activity.  We have evolved to move.
Sadja Greenwood, MD, MPH

Tuesday, December 18, 2018

Raisins and Green Tea Can Help your Teeth and Gums

Dr. Christine D. Wu is a professor and Associate Dean for Research at the University of Illinois at Chicago College of Dentistry.  For several years she has studied compounds that can fight the bacteria that cause cavities and gum disease.  She has looked at antioxidant compounds in raisins and found that oleanolic acid in raisins inhibits the growth of two species of  oral bacteria – Streptoccocus mutans, which causes cavities, and Porphyromonas gingivalis, which causes periodontal (gum) disease.  The compound blocked S. mutans  from adhering to tooth surfaces.  Adherence is crucial for bacteria to form dental plaque, the sticky biofilm  consisting of oral bacteria that accumulates on teeth.  When you eat a sugary meal, these bacteria release acids that erode the tooth enamel.   “Raisins are perceived as sweet and sticky, said Dr. Wu,  “and any food that contains sugar and is sticky is assumed to cause cavities. But our study suggests the contrary.  Phytochemicals in raisins may benefit oral health by fighting bacteria that cause cavities and gum disease.”   However, bran cereals that have added sugar and raisins are not the best.  Finding a cereal without added sugar such as oatmeal, and adding raisins to it would be better. Raisins can also be enjoyed as a snack, along with nuts, during the day. People with diabetes should test their blood sugar values if they snack on raisins, as data about this has been controversial.  

The ability of tea to fight dental caries has been suggested for decades.  The polyphenols in tea, especially EGCG (epigallocatechin gallate) have been shown to inhibit dental plaque accumulation, but the exact mechanisms are not clear.  Dr. Wu and her colleagues think that EGCG suppresses genes in S. mutans  and prevents the initial attachment of this bacterium to the teeth, and thus the formation of mature biofilms.  The effects of ECGC  on other  properties of S. mutans were also studied.  The research showed a dose dependent inhibition of the initial attachment of S. mutans and also an effect on the genes of this bacterium.  These findings suggest that ECGC may represent a novel and natural way to inhibit biofilm formation on the teeth.   ECGC is also being studied in laboratories throughout the world for its properties to combat many systemic diseases.  Stay tuned.

 You may be aware that green tea has much more ECGC than black tea, although they come from the same plant.  Researchers have warned that excessive amounts of ECGC found in some supplements can lead to toxicity and liver damage, so it is prudent to avoid high doses of this supplement. Brew green tea and swish it around in your mouth before swallowing.  Enjoy one or more cups a day, depending on your tolerance for caffeine, Green tea has about 1/3 to 1/2 the caffeine as coffee.  Kukicha green tea is made of the stems, stalks and twigs of the tea plant and is naturally low in caffeine. Powdered green tea, such as matcha, is considerably stronger. Water to brew a cup of green tea should be less than boiling temperature, around 150 to 160  degrees F . 

May all be well on your next trip to the dentist!

Sadja Greenwood, MD, MPH

Monday, December 3, 2018

Help the environment by keeping your cell phone! And more

You have read of the new report on climate change from the U.S. government, saying that what the earth is experiencing is unlike anything in the past, that the global average temperature is much higher and is rising more rapidly than anything modern civilization has ever gone through..  This warming trend can only be explained by human activity.  Our country could lose hundreds of billions of dollars, or more than 10% of its GPD by the end of the century.  Rising oceans can flood many coastal cities and towns, including Bolinas. The US Global Change Research Program  is a team of 13 federal agencies and was put together by a group of 1,000 people, including 300 leading scientists, roughly half from outside the government.

There are many suggested steps that people can take, and I will list some of them.  The first came from a New York Times article this week, concerning cell phones.  The problem isn’t the power needed to charge your phone (although that can add up)  “but the tremendous energy needed to mine 60 plus metals and assemble them into a new device.  A 2015 study found that producing an iPhone 6 released the equivalent of 178 pounds of carbon dioxide – about as much as running a modern refrigerator for a year.” Most people change cell phones every 2 years.  Lofti Belkhir, an entrepreneur and engineering professor at McMaster University in Hamilton, Ontario, says that cell phone business models promote frequent upgrades while masking the true financial and environmental costs of new phones. His research suggests: hang on to your phone as long as possible.  Extend its life by fixing it when things break, cleaning the charging port and swapping out dying batteries.  If you must replace your phone, recycle your old one and consider buying a used one.  Purchasing fewer new phones will send a message to industry that it needs to change.

Many of us feel there isn’t enough we can do as an individual to address climate change.  That’s why it’s important to join with others in effective organizations. is an international organization founded by environmentalist Bill McKibben of Middlebury College to work on these goals: keep carbon in the ground, build a new and more equitable low carbon economy, and pressure governments into limiting emissions. If you look at you can get on their mailing list for information. 

Be aware that California is joining Hawaii in going carbon-free by 2045 by having all electricity free of fossil fuel origin. This is amazing!  Salt Lake City, Atlanta, San Diego, Pittsburg and Portland have all announced they are going 100% renewable.  

 Here are other things an individual can do: Drive less, carpool, use a fuel efficient car, take a train or bus rather than a plane whenever possible.   Eat less meat – because almost 15% of human induced greenhouse gases come from livestock. Waste less food  - buy only what you need and take your own container to a restaurant to wrap up what’s left over.  Install rooftop or backyard solar panels.  Use water carefully, by planting native plants instead of a lawn.  You and your state are powerful and you should feel effective in making these moves.  Basically they are for your children and grandchildren. If I have left out moves that you feel are important, please let me know on my website and I’ll print them in my next column.
Sadja Greenwood, MD,  MPH   leave me a comment!

Tuesday, November 20, 2018

What’s the Impact of Time Change?

Californians just voted to make Daylight Savings time last year round.    Basically they were voting to eliminate the twice yearly change that people tend to like in the fall, when the clock is set back and you gain an hour of sleep, and dislike in the spring when the clock is set an hour forward, and you lose an hour in bed.  Why is this important from the point of view of your health?

Studies have shown that there is a 24% increase in heart attacks in the week after ‘spring forward’ because of losing that hour of sleep, and a significant increase in fatal auto accidents in the week following the shift.  Pedestrian deaths are also increased. When the change occurs in the fall, with people gaining an hour of sleep, the opposite is true.  Why was the vote to keep Daylight Savings time rather than Standard time?  

Daylight saving time originated as an energy saving measure during World War I and was adopted sporadically in peacetime. In 1966, amid confusion over a patchwork of schemes in each state for beginning and ending daylight saving time, Congress stepped in with the Universal Time Act to standardize it nationwide. States could opt out of daylight saving time — it’s not observed in Hawaii because this state, the farthest south, doesn’t see a big difference in daylight hours between winter and summer months.  Most of Arizona is on standard time all year but the Navajo Nation does use Daylight Savings time.This is because the Navajo Nation also lies partly in New Mexico and Utah, which make the changes. The Hopi Tribe within the Navajo Nation goes along with the rest of Arizona.  

Despite the fact that daylight saving time was introduced to save fuel, there isn’t strong evidence that the current system actually reduces energy use — or that making it year-round would do so either. Studies that evaluate the energy impact of daylight savings are mixed. It seems to reduce lighting use (and thus electricity consumption) slightly but may increase heating and AC use, as well as gas consumption. It’s probably fair to say that energy-wise, it’s a wash.   

Democratic Congressman Kansen Chu authored Proposition 7,which allows the state Legislature, with a two-thirds vote, to make California’s daylight saving time last year round, provided it is agreed to by the federal government. Currently, it is not, though there is already a Florida bill pending in Congress that could change that. Chu is satisfied that legislation will suffice to clear the federal hurdles and said he’ll focus on winning over the two-thirds of the state Legislature, where some of his colleagues have argued things are fine the way they are. National Parent Teachers groups oppose permanent daylight savings because of safety concerns with children going to school in the dark.  Chu initially suggested ditching daylight saving time and keeping standard time all year, but youth sports leagues said that would keep them from holding weekday practices and games after work and school because darkness would come too early. So Chu switched gears and pushed for permanent daylight saving time instead.  

Obviously this is a complicated issue, and here’s the take home message.  Sleep is a vitally important issue for your body, your heart, and your safety on the road.  Resolve to get enough of it every day, and go to bed an hour early before Daylight Savings time comes around so you won’t suffer so much in the following week. Pay attention to jet lag – many people use melatonin to get them through the adjustment.  If your friends pride themselves on how little sleep they need, start priding yourself on how much you enjoy a full 7 to 8 hours or more. Your brain and your body will thank you!!
Sadja Greenwood, MD,MPH

Monday, November 5, 2018

The Benefits of Garlic

A study from the University of Saskatchewan and UCLA on garlic and heart disease was published in the Journal of Nutritionin 2016.  It was a review of thousands of studies on animal and humans evaluating garlic’s effects and safety. The authors looked at the medical literature on garlic supplements and their effects on high blood pressure, cholesterol,, C-reactive protein (an indicator of inflammation) and coronary artery calcium, as well as available data on side effects..  Only double blind, randomized, controlled trials were included.  In other words, this was a very careful study.. What was found was that garlic supplementation reduced blood pressure by 7-16 mm Hg systolic and 5-9 mm diastolic. It reduced total cholesterol by varying amounts: 7.4 to 29.8 mg/dl in various studies.  The most consistent benefits were shown in studies that used aged garlic extracts.  Although garlic is generally safe, rare adverse reactions were documented.   The authors concluded that garlic supplementation has the potential for cardiovascular protection based on risk factor reduction.  

The take home message from this, and other studies on garlic, is that it is a powerful vegetable we should include in cooking and also as a supplement if needed.  It is a member of the allium family of vegetables including onions, leeks, shallots and chives, all of which are healthy and flavorful. To prepare garlic in your cooking – select a few cloves, peel them and crush or chop them.  Let the garlic then rest for at least 10 minutes before cooking, - this triggers an enzyme reaction that boosts the healthy properties of garlic.  Cooking the garlic for a shorter time will enhance its effectiveness.  You can also add raw garlic to hummus, salads and soups. The most well-known aged garlic extract is Kyolic, but there are several others on the market.  

Sadja Greenwood, MD, MPH   past columns on this blog   leave me a message or a question

Monday, October 29, 2018

The Cerebellum – Surprising New Findings

The cerebellum is located on the underside of the brain and has been thought to be limited to controlling movement. It has been treated like an afterthought by researchers studying higher brain functions. However, researchers at Washington University School of Medicine in St. Louis say overlooking the cerebellum is a mistake. Their findings, published Oct. 25, 2018 in Neuron, suggest that the cerebellum has a hand in every aspect of higher brain functions -- not just movement, but attention, thinking, planning and decision-making.
"The biggest surprise to me was the discovery that 80 percent of the cerebellum is devoted to the smart stuff," said senior author Nico Dosenbach, MD, PhD, an assistant professor of neurology, occupational therapy and of pediatrics. "Everyone thought the cerebellum was about movement. If your cerebellum is damaged, you can't move smoothly -- your hand jerks around when you try to reach for something. Our research strongly suggests that just as the cerebellum serves as a quality check on movement, it also checks your thoughts as well -- smoothing them out, correcting them, perfecting things."
Dosenbach is a founding member of the Midnight Scan Club, a group of Washington University neuroscientists who have taken turns in an MRI scanner late at night, scanning their own brains for hours to generate a massive amount of high-quality data for their research. A previous analysis of Midnight Scan Club data showed that a kind of brain scan called functional connectivity MRI can reliably detect fundamental differences in how individual brains are wired.
Postdoctoral researcher and first author Scott Marek, PhD, decided to apply a similar analysis to the cerebellum. In the better-known cerebral cortex -- the crumpled outer layer of the brain -- wiring maps have been drawn that connect distant areas into networks that govern vision, attention, language and movement. But nobody knew how the cerebellum is organized in individuals, partly because a quirk of MRI technology means that data obtained from the underside of the brain tend to be low quality. In the Midnight Scan Club dataset, however, Marek had access to more than 10 hours of scans on each of 10 people, enough to take a serious look at the cerebellum.
Using the cortex's networks as a template, Marek could identify the networks in the cerebellum. Notably, the sensory networks are missing -- vision, hearing and touch -- and only 20 percent of the cerebellum is devoted to movement, roughly the same amount as in the cerebral cortex. The remaining 80 percent is occupied by networks involved in higher-order cognition: the attention network; the default network, which has to do with daydreaming, recalling memories and just idly thinking; and two networks that oversee executive functions such as decision-making and planning.
"The executive function networks are way overrepresented in the cerebellum," Marek said. "Our whole understanding of the cerebellum needs to shift away from it being involved in motor control to it being more involved in general control of higher-level cognition."
The researchers measured the timing of brain activity and found that the cerebellum was consistently the last step in neurologic circuits. Signals were received through sensory systems and processed in intermediate networks in the cerebral cortex before being sent to the cerebellum. There, the researchers surmise, the signals undergo final quality checks before the output is sent back to the cerebral cortex for implementation.
"If you think of an assembly line, the cerebellum is the person at the end who inspects the car and says, 'This one is good; we'll sell it,' or 'This one has a dent; we have to go back and repair it,'" Dosenbach said. "It's where all your thoughts and actions get refined and quality controlled."
People with damage to their cerebellum are known to become uncoordinated, with an unsteady gait, slurred speech and difficulty with fine motor tasks such as eating. The cerebellum also is quite sensitive to alcohol, which is one of the reasons why people who have had too many drinks stumble around. But the new data may help explain why someone who is inebriated also shows poor judgment. Just as a person staggers drunkenly because his or her compromised cerebellum is unable to perform the customary quality checks on motor function, alcohol-fueled bad decisions might also reflect a breakdown of quality control over executive functions.
Marek also performed individualized network analyses on the 10 people in the data set. He found that while brain functions are arranged in roughly the same pattern in everyone's cerebellum, there is enough individual variation to distinguish brain scans performed on any two participants. The researchers are now investigating whether such individual differences in cerebellar networks correlate with intelligence, behavior, personality traits such as adaptability, or psychiatric conditions., Dosenbach said: There are four times as many neurons in the cerebellum as in the cerebral cortex, so if you're leaving out the cerebellum, you've already shot yourself in the foot before you started. The promise of imaging the whole human brain at once is to understand how it all works together. You can't see how the whole circuit works together when you're missing a major piece of it."
This article comes from an October 25th post from the website Science Daily. Materials provided are from the Washington University School of Medicine
The take -home message from these findings are - treat your brain with great care!  Avoid head injuries in sports; don’t let your kids play tackle football. Headers in soccer can also be dangerous.  Treat alcohol and other drugs with caution.  Do some exercise – it stimulates the production of new brain cells.  Getting adequate sleep helps the brain, as do self-calming practices such as meditation. Eating a plant based diet low in salt will prevent obesity and high blood pressure, which will favor brain health. Your brain makes you, you.  Have a lot of respect for yourself, as well as others!
Sadja Greenwood, MD, MPH   leave me a message

Monday, October 15, 2018

The Health Risks of Alcohol

On August 24, 2018, the Lancet published a paper based on a study from the University of Washington,concluding that there is no safe level of drinking alcohol. The Lancet is a renowned English and international medical journal.  The study shows that in 2016, nearly 3 million deaths globally were attributed to alcohol use, including 12 percent of deaths in males between the ages of 15 and 49.

"The health risks associated with alcohol are massive," said Dr. Emmanuela Gakidou of the Institute for Health Metrics and Evaluation at the University of Washington and the senior author of the study. "Our findings are consistent with other recent research, which found clear and convincing correlations between drinking and premature death, cancer, and cardiovascular problems. Zero alcohol consumption minimizes the overall risk of health loss." Gakidou is a professor of health metrics sciences at the UW School of Medicine, and of global health at the UW School of Public Health.
The study does not distinguish between beer, wine, and hard liquor due to a lack of evidence when estimating the disease burden, Gakidou said. However, researchers used data on all alcohol-related deaths generally and related health outcomes to determine their conclusions.
Alcohol use patterns vary widely by country and by sex, the average consumption per drinker, and the attributable disease burden. Globally, more than 2 billion people were current drinkers in 2016; 63% were male.  Alcohol use was less in countries with large numbers of Muslims, as Islam forbids and discourages drinking.  
The study looked at deaths and overall poor health attributable to alcohol for 23 health outcomes, such as communicable and non-communicable diseases and injuries, including:
  • Cardiovascular diseases: atrial fibrillation and flutter, hemorrhagic stroke, ischemic stroke, hypertensive heart disease, ischemic heart disease, and alcoholic cardiomyopathy;
  • Cancers: breast, colorectal, liver, esophageal, larynx, lip and oral cavity, and nasal;
  • Other non-communicable diseases: cirrhosis of the liver due to alcohol use, diabetes, epilepsy, pancreatitis, and alcohol use disorders;
  • Communicable diseases: lower respiratory infections and tuberculosis;
  • Intentional injuries: interpersonal violence and self-harm;
  • Unintentional injuries: exposure to mechanical forces; poisonings; fire, heat, and hot substances; drowning; and other unintentional injuries; and
  • Transportation-related injuries.
"We now understand that alcohol is one of the major causes of death in the world today," said Lancet Editor Richard Horton. " We need to act urgently to prevent these millions of deaths. The myth that one or two drinks a day are good for you is just that -- a myth. This study shatters that myth."
The take home message from this study is complicated.  Companies providing beer, wine and hard liquor are enormously large and powerful, permeating the world of sports, dining and agriculture. Cutting down on alcohol use means resisting pressures from many directions – advertising, friends, social events, and habits.  If you want to abstain, and can go 3-4 days without alcohol, you are probably not seriously addicted and can make the shift. You may decide to have a single drink on special occasions, such as your birthday, but be sober at other events.   If you have been a regular drinker and have great difficulty abstaining a day or two, you should see your doctor to discuss the possible use of temporary drugs to help you through the transition to sobriety.  In either case, you should start going to AA meetings, both for help and to meet other non-drinkers.  You will get a sponsor who will help your transition.  Don’t worry if you don’t believe in a God – the group itself, or nature, can function as your higher power.  
Sadja Greenwood, MD, MPH    back issues on this blog

Monday, October 8, 2018

Are Sugar-Free Chemicals Affecting Your Gut?

According to a new paper by researchers at Ben-Gurion University in Israel and Nanyang Technological University in Singapore, FDA-approved artificial sweeteners and sport supplements were found to be toxic to digestive gut microbes. The  study looked at the relative toxicity of six artificial sweeteners (aspartame, sucralose, saccharine, neotame, advantame, and acesulfame potassium-k) and 10 sport supplements containing these artificial sweeteners. The bacteria found in the digestive system became toxic when exposed to concentrations of only one mg./ml. of the artificial sweeteners.  The researchers modified  bioluminescent E. coli bacteria, which luminesce when they detect toxicants and act as a sensing model representative of the complex microbial system,.  They stated: "This is further evidence that consumption of artificial sweeteners adversely affects gut microbial activity which can cause a wide range of health issues."
Artificial sweeteners are used in countless food products and soft drinks with reduced sugar content. Many people consume this added ingredient without their knowledge. Moreover, artificial sweeteners have been identified as emerging environmental pollutants, and can be found in drinking and surface water, and groundwater aquifers. According to the researchers - "The results of this study might help in understanding the relative toxicity of artificial sweeteners and the potential of negative effects on the gut microbial community as well as the environment. Furthermore, the tested bioluminescent bacterial panel can potentially be used for detecting artificial sweeteners in the environment.”
Diet Coke, Diet Pepsi, Sprite Zero and other sports drinks contain aspartame and acesulfame potassium as artificial sweeteners, along with other ingredients for flavoring. Splenda is sucralose.  
As you are aware, your gut microbes play a large role in your digestive health, your weight and the strength of your immune system.  They thrive on a diet with lots of fiber from vegetables and fruits.  This recent study, published in the journal Molecules, can be toxic to these important bacteria.  
What are your alternatives for a thirst-quenching drink that will not harm your gut and allow you to avoid sugar?  Slice an organic orange, other fruit or cucumber into a glass bottle of water and sip from it during the day.  Add mint and other herbs.  Drink plain coffee and a variety of teas, Sweeten with small amounts of stevia (this plant derived sweetener may not be safe for the kidneys with excessive use, but is considered safe as ordinarily used.)  Yacon syrup, derived from a plant grown in the Andes, is another recently popular sweetener.  It has not been extensively studied, but should probably be used sparingly.  The syrup can cause abdominal pains, nausea, bloating and diarrhea when taken in doses greater than two teaspoons a day.  You can retrain your taste buds to prefer unsweetened foods.  If you order or make a fruit smoothie, use a permanent straw – not a disposable plastic one.  Try a few raisins and nuts for a treat.  

Let’s celebrate Indigenous Peoples Day.  

Sadja Greenwood, MD. MPH

Monday, September 24, 2018

The Exercise Paradox – Are We Designed to Sit on the Couch?

We all know that exercise is good for the body and brain, and yet we are becoming less active as work has become more sedentary.  If getting out for a walk, or taking a trip to the gym seems difficult, researchers at the University of British Columbia say that the problem is real, and it’s happening inside your brain. Research findings, published recently in the journal Neuropsycologia, say that we may be designed to prefer lying on the couch.  Matthieu Boisgontier, lead author of the paper, wrote “Conserving energy has been essential for human’s survival, as it allowed us to be more efficient in searching for food and shelter, competing for sexual partners, and avoiding predators. The failure of public policies to counteract the pandemic of physical inactivity may be due to brain processes that have been developed and reinforced across evolution.”
In their study, the researchers had young adults sit in front of a computer. They flashed sequential images of stick figures that depicted either physical activity such as running, biking and swimming, or inactivity, such as sitting or lying down. Subjects were told to move their markers as quickly as possible toward the pictures of physical activity and away from the pictures of inactivity.  Subsequently, the order was reversed.  Electrodes were recording their brain activity.  While participants were faster at moving towards the active pictures and away from the lazy pictures, brain results showed that this required their brains to work harder.  Avoidance of physical inactivity comes as a cost – namely increased involvement of brain resources.  Boisgontier said “These results show that our brain is innately attracted to sedentary behaviors.”   Researchers asked whether people’s brains can be retrained, adding that knowing what is happening is an important first step.  
I found this paper to be astounding.  What are its take-home messages?  I think it’s important to knowthat the lure of the chair, the hammock and the bed is innate and powerful.  If we want to stay strong and feel well, we have to find ways to balance resting and moving.  We are all aware that physical activity, including walking, is beneficial for the brain, bones, muscles, heart and most body organs.  It helps with weight control and diabetes prevention. Therefore, we have to plan to get movement into our lives. Do more work in your garden, or home.  Join a class, or a team. Take Pilates, dance classes, Qigong or Tai Chi. Form a group with friends to walk, talk and visit the gym. If you are a solitary person, you can find good exercise classes of all kinds on line.   Set an alarm to get you up from the chair hourly during the day.  We humans are endlessly inventive.  Knowledge is powerful.  Let’s go for it!
Sadja Greenwood  MD, MPH

Monday, September 17, 2018

Plastic Pollution – What Can You Do?

First comes knowledge.  When I read that a friend, Laurie Riley, was not buying any plastic goods or anything wrapped in plastic, I was galvanized. People are changing from despair into action!  Several long conversations with Laurie have taught me what an individual, and better yet, a group, can do.  Here goes, with many thanks to Laurie.  

China is no longer accepting our plastic waste for recycling.  Huge amounts are piling up at recycling centers, and much of it is going into landfills or just sitting with no place to go. These centers will not be able to accept the mounds we are creating, and side effects will be toxic to the environment.  Remember the saying – Reduce, Reuse, Recycle?  We must Reduce and Reuse starting now. Recycling has become a very difficult predicament.

 Pollution of the oceans is an enormous problem. Over 5 trillion pieces of plastic currently litter the ocean,, accumulating in in 5 huge ‘gyres” throughout every ocean.  The biggest one is between Hawaii and California; the large and tiny pieces of plastic therein are killing fish, ocean mammals, birds and even plankton.  

Enter Boyon Slat, a young Dutch inventor, entrepreneur and Aerospace Engineering student dropout who founded the company - The Ocean Cleanup. He is 24.  He has developed and built a floating device that has sailed through the Golden Gate heading for the gyre.  Slat estimates that they will deploy 60 of these free-floating barriers in the ocean by 2020.   They hope to remove 50% of the Great Pacific Garbage Patch in 5 years. The free-floating barriers are made to withstand harsh weather conditions and constant wear and tear.  After two decades they hope to have collected 90% of the trash in the patch. The Ocean Cleanup has raised $35 million so far in crowd funding, with generous donations from Marc Benioff  of Salesforce and Peter Thiel of  Paypal.  

Obviously it is important that we humans throughout the world reduce the millions of tons of plastic that we discard yearly. Scouring the beaches for waste is a good approach.  Changing our buying habits is also necessary.  Take note of the plastic bags you now have, and reuse them over and over. Don’t take new ones; use your own cloth bag to go shopping.  Try to avoid packaged foods, which almost always come in plastic. Make cloth baggies to use when you buy in bulk. Never accept a plastic straw for your drinks; you can find reusable ones in many places, including at the store cited below. Compost your food waste – it’s easy to do and you will be rewarded with great soil for your garden.  Jennie Pfeiffer is a ‘master composter’ so you can give her a call for suggestions. 

For a store that has a great many products made without plastics, including tooth brushes, straws, deodorants, cosmetics and lots of kitchen ware, visit  They are based in New York, but have plastic-free shipping. Shipping is free for orders over $50.  Look over their selections – it may work for you.  The founder of this store is Lauren Singer, who has a blog called Trash is for Tossers, and has put all the trash she has produced in the past five years into a 16oz mason jar!

You can follow the ocean cleanup progress at  You can read the definitive book on living without plastic by Beth Terry – Plastic Free – How I Kicked the Plastic Habit and How You Can Too.  Again – many thanks to Laurie Riley and to all of you who are working for a cleaner environment.  

Sadja Greenwood, MD, MPH  back issues on this blog