The wisdom of Hippocrates

Historians agree that Hippocrates was born around the year 460 BC on the Greek island of Kos.  Little else is known about him, but much wisdom is attributed to him:

  • “It is far more important to know what person the disease has than what disease the person has.”
  • “Let food be thy medicine and medicine be thy food.”
  • “Walking is man’s best medicine. ”

We seem to have forgotten this wisdom in our 21st century focus on treating illness rather than the whole person and rather than preventing illness.

Hippocrates reputedly lived until the age of 90, quite remarkable for his era.  Perhaps it was a nutritious diet, plenty of exercise, fresh air, and sunshine that was the secret to his longevity!

Lowering the risk of developing non-contagious diseases

If there was a cheap pill which lowered your risk of developing non-contagious diseases such as heart disease, depression, dementia, and cancers, would you take it?

Of course, there is no such pill.  But there are ways that you can lower the risks.

You will probably guess what these ways are, but to understand why it is necessary to review the path of human evolution.  This information was recently provided by Herman Potzer in Scientific American, January 2019.

Our closest living relatives, the great apes have quite low levels of physical activity, yet suffer no ill health effects as a consequence.  But humans evolved on a different path beginning some six million years ago.  As we descended from the trees there were gradual anatomical changes.  The size of the brain increased substantially.  Our physiology adapted to the intensive physical activity that hunting and gathering requires.

Humans have evolved to require far higher levels of exercise to be healthy.  We have developed a dependence on physical activity.  We do need at least 10,000 steps per day.

According to Wikipedia “The Paleolithic diet, Paleo diet, caveman diet, or stone-age diet is a modern fad diet requiring the sole or predominant consumption of foods presumed to have been the only foods available to or consumed by humans during the Paleolithic era”.  This means a diet with much less fat, processed foods and especially sugar.

But to go with the diet, we need the activity of the hunter gatherer, as well as the food, in order to be healthy.  Our large brain size suggests that we also need frequent mental activity.

Here are some guidelines for limiting the risk of developing some specific diseases.

Bowel cancer

An article in The Age on January 22, 2019, reported that the incidence of bowel cancer amongst young adults is rising – by up to 9.3% per year since the mid-2000’s.  This information is based on a study published in “Cancer Epidemiology, Biomarkers and Prevention” this month.   Lead author Eleonora Feletto, Research Fellow at Cancer Council NSW, said that eating less red meat and processed meat, limiting alcohol intake, not smoking, and increasing physical activity are all lifestyle factors which reduce bowel cancer risk at all ages.

Eating less red meat also has side benefit – it will reduce the greenhouse gasses emitted by cattle and so help to limit climate change.


ABC news reported on 24 January 2019 that a new study published in JAMA Psychiatry provides the strongest evidence yet that exercise has a protective effect against depression.  Based on genetic and other data from 300,000 adults, the study found that replacing sedentary behaviour with 15 minutes of vigorous activity each day can reduce depression risk by roughly 26 per cent.  While such a correlation had already been identified, the use of genetic data shows a causal path.  The research team looked at people who carry genetic variants associated with increased physical activity, and whether these variants impacted their risk of depression.  It was found that higher levels of physical activity (objectively measured, and indicated by associated gene variants) were linked to lower levels of depression.


In April 2017, Scientific American carried an article by Miia Kivipelto and Krister Hakansson, both at Karolinska Institute Sweden, which reported on a gold-standard clinical trial that found that cognitive impairment can be prevented or delayed by promoting changes in behaviour and by managing vascular risk factors.

In the trial, 1,260 men and women between the ages of 60 and 72 were randomly assigned to a control group and a treatment group.  The trial took place between 2009 and 2011.  Two hundred experimental drugs intended to treat Alzheimer’s disease have failed in the past 30 years but association studies over the past 15 years have indicated that good diet, exercise, an active social life, and the achievement of higher education levels may diminish the risk of Alzheimer’s and other dementias later in life.

The main ingredients in the recommended diet of the intervention group were fruits, vegetables, whole grains and rapeseed oil, along with a fish meal at least twice a week.  The only food supplement was vitamin D.  The physical exercise included muscle-strength training, aerobic exercise, and posture balance.  The intervention group also used a computer program to train on a range of cognitive tasks including memory improvement.

After two years the treatment group showed clear benefits: overall cognitive performance improved on average in both the treatment and control groups, but the treatment group benefitted 25% more than did controls.  The risk of waning cognitive performance was 30% higher in the control group.

More recently, a study published in Nature Medicine by Xu Chen and Li Gan (“An exercise-induced messenger boosts memory in Alzheimer’s disease”, January 2019) suggests that a hormone released during exercise, Irisin, which initiates biochemical reactions throughout the body.  Irisin does exist in the brain.  There is, as yet, no proof that this hormone can prevent Alzheimer’s but it may allay some of the effects.   The hormone appears to operate by enhancing synaptic plasticity and memory.

Prostate cancer

An informative book on prostate cancer is Dr, Patricks Walsh’s guide to surviving prostate cancer (fourth edition, 2018) co-authored by Janet Farrar Worthington.

Walsh and Worthington say that there are some risk factors we can’t do anything about, such as age and being of African ancestry.

Their advice about what men can do to reduce the risk of developing prostate cancer includes:

  • Lose weight.  Too much fat, especially around the middle, increases a man’s risk of developing prostate cancer that is more aggressive and more likely to be fatal.
  • Don’t smoke.  Smoking does not appear to cause prostate cancer, but smokers who develop prostate cancer are more likely to die of it.
  • Eat smarter – the relationship between diet and prostate cancer is complex and it cannot be definitely said that eating too much red meat causes prostate cancer.  Variety is the best advice, focused on a diversity of high nutrient foods and a minimum of junk food.
  • Exercise.  Scientists are increasingly sure that a lack of exercise has an influence on the development of the disease, especially on lethal prostate cancer.  Exercise helps men do better at every stage of the disease.

More on prostate cancer at

Other cancers

Fourteen cancer types, including breast cancer, have been declared by the World Cancer Research Fund to be associated with being overweight and especially obese (The Age, February 4, 2019).  The recommendations are more exercise and eating more fruit, vegetables, and whole grains.

Heart disease

Heart disease and stroke are major killers.  Lifestyle recommendations to lower the risk include:

  • Don’t smoke;
  • Good nutrition – choose a diet that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, nontropical vegetable oils, and nuts; and limits intake of sweets, sugar-sweetened beverages, and red meats.
  • Be physically active every day to a total of at least 150 minutes per week.
  • Then of course, there is blood pressure, cholesterol, and triglycerides to minimise.


We are not taking these evolutionary precautions

Many of us are not taking the advantage of the healthy lifestyle which we have evolved to require.

An October 2018 report by the Australian Institute of Health and Welfare ( “Nutrition across the life states” shows that a high proportion of people do not have a healthy diet and that this starts at a young age.

The report shows that:

Australians of all ages generally:

  • do not eat enough of the 5 food groups—vegetables, fruit, grains, meat and alternatives, and dairy products and alternatives
  • eat too much food that is high in energy and low in nutrients (‘discretionary food’)
  • eat too much sugar, saturated fat, and sodium (salt).

This suboptimal food and nutrient intake begins from an early age (as young as 2), which means  good eating practices are not being established in early childhood to take forward into adulthood.

Despite this, the nutrient intake and nutrient status of Australians is generally adequate, but physical activity levels are low, and levels of overweight and obesity are high.

Leading contributors to discretionary food intake include pastries, snack foods and ice cream, while for adults, alcoholic drinks also dominate. Although sugar-sweetened drinks are leading contributors to added sugars intake, they feature lower down the list of leading discretionary  foods for most age groups.

Perhaps in two million years, humans will have evolved to remain heathy with a sedentary lifestyle and a diet of processed food with little in the way of vegetables or fruit.  That will be too late for you and I.

There are, of course, other factors which can cause disease even in people who stick to the evolutionary guidelines and I will write more on this in future posts.

Charlie Nelson




The eclipse and the owl

The total eclipse of the Moon over Melbourne encouraged me out of bed at 3.30am on 28 July 2018.  An alignment last seen over 1200 years earlier was the main attraction.  A very bright Mars was to accompany the Moon through a longer than normal total eclipse.

I was standing at my tripod-mounted camera taking photos of the early stages of the eclipse when I heard a rustle behind me.  Then a bird flew close to my head and perched on a nearby fence.  It was too dark for birds!  I shone my torch towards it and saw that it was an owl!  It flew away too soon for me to identify the species of owl, but I was pleased that it was in the neighbourhood and that I had seen it.

A rare eclipse and a rare sighting of an owl in suburbia!  What did this very rare conjunction mean?

It probably signified nothing, but my imagination had been stimulated.

The owl is associated with wisdom in most cultures and also with wealth in others, especially in India.  Whatever wisdom I may possess, I was certain that I was lacking in wealth.  Could this alignment of the moon, a planet, and an owl be a harbinger of changing fortune?  I hoped so, but understood that this was simply an unlikely random event – and they happen frequently!

What we experience in this world is so unlikely as to be almost impossible.  Out of the billions of stars, how many harbour life?  None that we have discovered yet.  Why is it that the Earth’s shadow is just the right size at the Moon’s orbit to eclipse the Moon?  Why is it that the Moon appears the same size as the Sun, despite the Sun being vastly larger?  The Moon is just the right distance away to totally eclipse the Sun when the astronomical geometry aligns.

The probability of these conjunctions is infinitesimal – no other planet in the solar system provides such events.  Likewise, the existence of life.

While all this is so unlikely that it seems like magic, what we are doing to our world has predictable consequences.  Extinctions, climate change, pollution of the air and the oceans, and the list goes on.  Yet we do nothing to stop the inevitable.

If only humans had the wisdom of owls!


On climate change and world hunger

Bjorn Lomborg, writing in The Australian newspaper of January 19 2018, claims that climate change policies may be making world hunger worse.

He notes that after years of decline in global hunger, it increased in 2016 affecting 815 million people, an increase of 38 million from 2015.

He notes that the FAO blames the rise on a proliferation of violent conflicts and climate-related shocks.

He says that achieving the Paris agreement on climate change will not change the frequency and severity of climate-related shocks and that the huge investment in mitigating climate change could make global hunger worse – by encouraging the production of bio fuels rather than food and by diverting resources from strategies to reduce world hunger.

I am not as confident as Lomborg that actions to reduce climate change will have no impact on the frequency and severity of future droughts and floods that can reduce food production.  Also, violent conflicts which affect world hunger can in themselves be an outcome of climate change.

We do have to tackle multiple problems, on multiple time horizons, simultaneously.

Here is a suggestion that can reduce world hunger and mitigate climate change.


In Australia, and in many other countries, greenhouse gas emissions are rising even though they are falling on a per capita basis (an excused used recently by Josh Frydenberg, the Australian government’s minister for energy and the environment, to justify Australia’s continued increase in greenhouse gas emissions).

Reducing world population growth will tend to reduce both future world hunger and future greenhouse gas emissions.

Increased access to family planning services in countries which are prone to bouts of food shortage would be a great investment for the future.

Will electric car dreams come true?

It is very pleasing that Josh Frydenberg is talking of a bright future for electric cars (More than electric dreams, The Age, January 13).  He cites three reasons for the low take-up of electric cars in Australia (high purchase price, low range, and lack of infrastructure).  There are at least two other reasons.  The price of electricity has increased by 126% in the past ten years, while the price of motor fuel has risen by only 3% and no doubt drivers are expecting more steep price increases for electricity in the future.  In addition, the vast majority of electricity is produced by burning coal, so recharging the battery will still result in carbon dioxide emissions.  What is needed is a plan to generate significantly more renewable energy at cheaper prices and to stop blaming renewable energy for electricity price rises.  Only then will electric cars become more than an electric dream.

The above is my original letter to The Age, which was published on January 17 2018.  The published letter was edited because the 3% increase in the price of automotive fuel over the past 10 years, while true, was considered to be unbelievable.  The price index fell during 2015 and 2016 which compensated for rises before and since.

There is another reason for resistance to electric cars, in Australia and elsewhere.  The batteries do not charge as quickly as filling a tank with petrol or diesel.  New technology, probably in the form of super-capacitors may fix that problem in the future.

The rainbow and marriage equality

The rainbow is an important symbol in most cultures dating back millennia.

In the Bible (Genesis 9:13) the “bow in the clouds” is an important symbol of the covenant between God and Earth.

In the legends of Australian Aboriginals, the Rainbow Serpent came from beneath the ground and created huge ridges, mountains, and gorges as it pushed upward. The Rainbow Serpent is understood to be of immense proportions and inhabits deep permanent waterholes.  It is in control of life’s most precious resource, water.

In Norse mythology, the rainbow connects the realms of the gods and humans.

Newton explained the physics of the rainbow and, according to Keats and others took the mysticism out of the rainbow.

The rainbow is a symbol of diversity and it has been adopted by the marriage equality campaign in Australia.  I support marriage equality because I think it will make a lot of people happy and I have seen no compelling evidence that it will do any harm.

Another reason I have for supporting marriage equality is that there are a lot of urgent problems confronting Australia, including a stagnant economy, energy supply, and climate change.  If we pass marriage equality into law, which is easy to do, we can then focus our minds on these other issues.

I have created a postcard to mark the magic and legends of the rainbow, as well as the diversity of Australians. – which should be celebrated and nurtured.

The postcard depicts the rainbow with one end on a termite mound at Cape Range national park near Exmouth in north western Australia (no pot of gold there).  It shows that the parliament and churches are overarched by the rainbow, as we all are.

The postcard can be purchased here.

Russia’s key role in resolving climate change

New Scientist magazine (5 October 2013, page 17) reported that the collapse of the USSR resulted in the largest ever human-made carbon sink.

When the USSR split into separate republics in 1991, the loss of government subsidies and privatisation of land resulted in 455,000 square kilometres of farmland being abandoned.

As plants reclaimed the land, 42.6 million tonnes of carbon have been locked away every year since 1990 – equivalent to storing 10% of Russia’s annual carbon dioxide emissions from fossil fuel.

More recently, The Age reported that Russian villages are disappearing as the population declines.  As a result of some villages and hamlets becoming deserted, trees grow up through the old roads, making them impassable (July 31, 2017, reproduced from the New York Times).

This is a good situation for mitigating climate change, even if it is not a deliberate strategy.  A smaller population, assuming that carbon dioxide emissions per capita are not growing, means a fall in total emissions.  And an increase in the number of trees means more absorption of carbon dioxide from the atmosphere.

United Nations population projections are for Russia’s population to decline from a figure of 144 million in 2017 to 133 million in 2050 and 124 million in 2100 (World Population Prospects, 2017 Revision).

Russia’s greenhouse gas emissions are rising after a large drop in the 1990’s, following the collapse of the Soviet Union.  Russia’s plans for emissions reductions are not ambitious and it is not clear that President Putin is convinced of the need for reductions (, accessed 6 September 2017).

It is just as well that new trees are growing – Russia is a relatively large emitter of greenhouse gasses.

Russia is important to resolving climate change in another way.  It has vast forests, greater than the Amazon.  It has approximately one-fifth of the world’s forest areas.  Significant clearing would release vast amounts of carbon dioxide, so it is vital that these forests are protected.

With a better commitment and strategy, Russia has the potential to make a major contribution to a global reduction in net emissions.

Light of Life

My photo book contains a selection of momentary ethereal lights.  Here are captions for the photographs.

Front cover: just after sunset in winter from Princes Bridge in Melbourne.  The Yarra river seems luminous.

Some versions have a different front cover: sunrise over a mist-shrouded Ararat.

Page 2: just before sunrise, Brunswick.

Page 3: Sunrise, Brunswick

Page 4: Stonehenge inspiration.  Sunrise at the winter solstice, Brunswick.

Page 5: Hawaii sunset

Page 6: Sunset, Great Western, Victoria

Page 7:  Just after sunset, Hawaii

Page 8:  Rainbow, Melbourne

Page 9: Rainbow, Melbourne

Page 10: Rainbow, Cape Range National Park, north western Australia

Page 11: Rainbow, Bali

Page 12:  Sunset, Ningaloo Reef, north western Australia

Page 13:  Storm viewed from St Kilda Pier, Melbourne.

Page 14: Royal Botanic Gardens, Melbourne.

Page 15: Yarra River reflections, Melbourne.

Page 16: Rainbow, Puerto Williams, Chile

Page 17: Rain and shafts of sunlight mingle, Tierra del Fuego, Chile.

Page 18:  Sunset, Tierra del Fuego, Chile

Page 19: Aurora Borealis, Tromso, Norway.

Page 20: clockwise from top left.  Sundog, Brunswick, 2012; total eclipse of the sun, Port Douglas 2012; Transit of Venus, Melbourne, 2012; total eclipse of the moon, Melbourne, 2011.

Back cover:  Sunset from Spencer Street Bridge, Melbourne.

Some versions have a different back cover: Morning colour at Philip Island.

Purchase the photobook.


Fallout from the Trump Paris Pullout

US President Donald Trump dumped America’s involvement in the 2015 Paris climate accord on 1 June 2017.  In doing so, he fulfilled an election pledge but also sealed the fate on a global climate change strategy.  We have been trying to achieve one since the 1992 Rio Earth Summit without a lasting agreement involving all major emitters.

His pullout is unlikely to result in more coal jobs in America, nor will it stop America’s progress towards a lower carbon dioxide intensity economy.  It is likely. However, that progress will be slower and it is possible that other countries will follow suit.

In May, the US Energy Information Administration reported that carbon dioxide emissions from electricity generation was the lowest in 2015 since 1993 – and 21% below the 2005 level.  The amount of electricity generated from coal powered stations peaked in 2005, displaced by natural gas (which emits 60% less carbon dioxide per kilowatthour of electricity) and renewables.   In 2015, coal provided 34% of total electricity generated, natural gas 32%, nuclear 20%, and renewables 13% (up from 8% in 2005).

Of more concern is the possible return to the debate about whether the climate is changing and whether we should do anything at all about it.  The re-emergence of anthropogenic climate change denial may slow progress and in particular, prevent bipartisan agreements on government strategy in countries like Australia.  This appears to be happening, threatening a repeat of bitter political fighting over the issue of emissions trading in the US and Australia in 2009 which resulted in an absence of effective long-term national strategy in both countries.

While we should continue to achieve a global accord, we need to increase efforts aimed at resolving the issue of climate change in the absence of one.  Indeed, other governments (federal, state, and local), companies, and individuals will need to step up their efforts to reduce emissions.  There is some evidence that this is happening.

This is a short extract from a book I am writing about how we can effectively deal with climate change, even in the absence of an international agreement – or in the case of Australia and the USA, without even a national agreement.


Orangutans in Sumatra

Report to supporters

Gail and Charlie’s field trip to Sumatra, May 2017

We had a very successful trip, which was both enjoyable and informative.  It also presented a few challenges.  We are in no doubt that the work of The Orangutan Project (TOP) in re-establishing a viable orangutan population is successful and worthy of support.  TOP also has projects elsewhere in Sumatra and in Borneo.  Details are available on their website.

The Project

Orangutans have been extinct in central Sumatra for over a century.  The project, led by Leif Cocks as chief of TOP, has been running for 15 years and is based on 38,000 hectares of concession bordering a national park of 144,000 hectares.  They hope to take over another concession of 20,000 hectares.

A population of over 170 orangutans has been established.  These are mostly formerly captive animals who TOP staff have schooled in how to live in the wild.  The objective is to increase the population to 500 so that there is sufficient genetic diversity to support natural growth to 2,000.

There are also 150 elephants, about 40 tigers, some sun bears, and many other animals.  The Sumatran tiger is nearly extinct and this represents perhaps one-third of the total population left.  The elephants are tracked to minimise the risks to them and to minimise conflicts with local villagers.

They employ 200 staff working in a wide range of activities, including security.

Our activities

There was no vehicle access to the Bukit Tigapuluh camp because heavy rain had caused some bridges to be damaged.  So after our six hour trip by car from Jambi, we had a four hour walk, carrying our backpacks, over a very muddy track and wading rivers.  It was hot and humid, plus we had been out of bed since 3am to fly from Jakarta to Jambi.  We were all tired by the time we got to bed.

We went out with technicians to observe recently released orangutans.  They use telemetry, which is enabled by a small transmitter attached to the orangutans, to track them.  This process goes on for three years after release, to ensure that they are thriving.  We saw several orangutans, including some who were no longer being tracked but came to observe us!

We were attacked by leeches from the forest floor, so we lost some blood.

Three days later, we had the four hour walk out so that we could be transported to the orangutan sanctuary where jungle school is conducted, on the other side of the national park.  This is where orangutans are taught how to live in the jungle.  They are kept in cages and fed what they will eat in the wild, but they are released for several hours a day to learn about the jungle.  They are monitored by observers during this time.  They are also provided with enrichment, which develops their problem solving skills.

This photo shows construction of one enrichment activity, which hides fruit and bush honey in amongst leaves within a section of fire hose,  Many other enrichment designs are deployed.

In the evenings, Leif Cocks provided interesting talks on the various aspects of the project.

A thief in the night

One night, at 12.30 am, Charlie heard something shuffling across the porch outside our hut.  Then there was something banging a short distance away.  It was a clear night with a full moon.  In the shadows of the trees, an animal was banging something onto the ground.  It looked like an orangutan so Charlie woke Gail to have a look.  She thought it unlikely that it was an orangutan because they sleep in their nests in the trees at night.

A short while later, there were more noises outside and the animal was closer and not shaded by the trees.  It was carrying a sheet of some material in one of its feet.  Charlie called Gail again and it was agreed that it was an orangutan.

Next morning, we found one of our neighbour’s boots on the track and Gail’s poncho also, that was what it had been dragging along.  We had left waterlogged boots and clothes on the porch to dry.  We had also left small containers of sunscreen and insect repellent.  These too were on the track – they had been opened and a finger had clearly explored the contents.

Coming back from breakfast, we noticed a muddy handprint on our neighbour’s door.  It was clearly left by an orangutan.  The doors were not locked.

The full moon plus a clear sky had provided an opportunity for exploration and mischief.

Our learnings

The establishment of a new orangutan population is the best way to release captive animals.  In other areas we have visited, they have been released into areas with existing populations – this may limit the opportunity for growth of existing populations despite being a good thing for the released animals.

Palm oil plantations are destroying what little forest is left.  We knew this, but did not know that plantations for paper are also increasing rapidly.  This means we must reduce demand for both palm oil and paper.  About 80% of the Sumatran forest has been lost to plantations and (mostly illegal) logging.

Leif Cocks is looking to establish rainforest shade grown coffee so that locals can make money from the forest while orangutans can still live in it.

There are rubber plantations and orangutans can survive in these, so long as a range of food trees are also established (green rubber?).

This visit confirmed that orangutans are our closest cousins.  They are very intelligent and capable of learning at all ages.

Overall, we were heartened by the work of TOP.  It is increasing the orangutan population and both protecting and expanding habitat for orangutans and other threatened animals.

The forest is vibrant with a diverse range of flora and fauna living in a symbiotic relationship.