Cold Chain Problem for Vaccines - Silk Worms can Help!

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The elimination of serious infectious diseases such as small pox and polio requires immense international collaborative effort. The World Health Organization, UNICEF, the Rotary Foundation, the Bill and Melinda Gates Foundation and many other groups are currently working on a number of infectious diseases, such as polio, tuberculosis, HIV/AIDS and diarrheal diseases.   Small pox was successfully eradicated in 1977, a momentous victory that required decades of work.   For polio and other serious infectious diseases, problems in poor countries include wars, lack of basic health infrastructure, lack of roads and electricity, ignorance and suspicion of the West, and anger stemming from the purported misuse of a Hepatitis B immunization program in Abbottabad to obtain DNA samples from suspected relatives of Osama bin Laden.  Workers bravely carrying out immunization campaigns in Pakistan, despite a fatwa from Islamist groups prohibiting vaccination, were killed in December 2012, and again January of 2013. Nine workers giving polio vaccine were killed in Nigeria in February, 2013.  Nigeria, Pakistan and Afghanistan are the only countries still reporting cases of polio. In resource-poor countries infectious diseases make up more than half of all deaths, and those who most need effective vaccines and antibiotics may not get them.  Measles is a leading killer of children worldwide, and can be prevented by vaccine, when and if it is available.

One of the problems with vaccination campaigns is the need to keep vaccines cold, when transporting them in hot areas which lack refrigeration and electricity. High temperatures are found to destroy almost half of the vaccines produced around the world.  Polio vaccine must be kept at 35 to 46 degrees F for vaccination to be successful.  Antibiotics and other medications also need to be protected from heat. According to the World Health Organization (WHO), as recently as 2008, almost half of all vaccines delivered to developing countries were ruined due to poor cold chain services. Further, cold chain “breaks” lead to ineffective vaccines being administered with a consequent loss of life and lack of vaccine compliance.

  Researchers at Tufts University have found that vaccines and other drugs can be stabilized in silk protein made from silkworm cocoons, enabling them to withstand temperatures as high as 140 degrees F for over 6 months.  They start with silkworm cocoons, boil them with sodium carbonate to separate a protein called fibroin, mix this with salt, then mix it with the substance to be preserved (the vaccine, or drug) and spread the result out as films, then freeze-dry it.  The films contain a fibroin matrix filled with tiny pockets that contain the medicine.  They are surprisingly stable for up to six months, regardless of temperature.  Silk protein is acceptable to the human body, used in wound closure, and may even have wound healing properties that are under investigation.  It can be taken orally without problems. Ultimately, substances made from silk may be used to replace a vein or a bone in the human body.  Tufts researchers note that silk protein can be used as packaging, for food and other products, thereby eliminating some of the problems of plastic use and disposal.

A team of four students from Harvard started a company, Vaxess Technologies, that is producing the new products, vaccines and medications, incorporated in silk fibroin.  In cooperation with the Tufts professors who developed the new silk technology, Vaxess hopes to have a product that will solve the cold-chain problem within a few years.  You can watch interesting videos on the new silk technologies presented by David Kaplan and Fiorenzo Omenetto (professors at Tufts) on TED or youtube.

Sadja Greenwood, MD, MPH   See other columns on this blog

Go to Health: Tomatoes All Year!


You might not expect that the latest on the benefits of tomatoes would come from the Lapland Central Hospital in Finland. Despite their short growing season, Finns are said to love tomatoes when they can get them. Finnish researchers studied what blood factors (from diet) were associated with a lowered risk of stroke in men, expecting to find correlations with levels of vitamins E and A. Instead, they found that men in the highest quartile of serum lycopene had a 55- 59% lower risk of stroke than those in the lowest quartile. Alpha and beta carotene, vitamin E and A were not associated with stroke risk.






Researchers at the College of Nursing, University of Kentucky, found that patients with heart failure who had the highest intake of tomatoes in their diet had longer times between adverse cardiac events.






Studies from Chungbuk National University in Korea found that tomato extract added to the diets of mice caused weight loss, despite a high-fat diet. Total cholesterol and LDL cholesterol were also reduced.






Studies from the University of Talca in Argentina found that rats supplemented with tomato extract had a reduction of platelet clumping, which would reduce blood clotting and improve blood flow.






Recent Canadian studies have looked at post menopausal women between 50 and 60 who were given lycopene-rich tomato juice, lycopene supplements or a placebo for 4 months. They were tested for blood markers of osteoporosis. Those taking tomato juice or lycopene were found to have reduced levels of bone breakdown compared to those given placebo. Subsequently, these researchers studied women who were told to restrict their intake of tomatoes or lycopene; in this study bone markers for osteoporosis were significantly increased.






U.S. studies from the 1990’s looking at male health professionals showed that frequent intake of tomato products was associated with a reduced risk of prostate cancer. Because further studies could not confirm this finding, Harvard researchers did a careful re-analysis in 2002 and again found a moderately reduced risk.






Tomatoes, which originated in South America and were first cultivated in Mexico, are clearly loved all around the world. Enjoy them! Do not start taking a lycopene supplement after reading this column. Excess intake of single carotenes may be counterproductive. There are many factors in tomatoes besides lycopene that can be healthy. Do start eating more tomato products while waiting for the ripe ones to come back into season. Tomato paste and low sodium organic Very Veggie are great choices – you can find them in our local stores in glass containers – free of BPA (Bisphenol A) and other chemicals. You can preserve homemade tomato sauce when they are in season; people lacking the time or expertise for home canning can simply freeze them. Here’s a great website from the University of Nebraska on easy ways to preserve tomatoes - http://food.unl.edu/web/preservation/freezing-tomatoes.






The beneficial compounds in tomatoes are best absorbed when eaten with fat, so include a healthy oil, such as olive oil, in your cooking or on your salad. Be careful of the high sodium content in many commercial tomato soups and sauces. You probably know that watermelon is also a good source of lycopene.






Next month I’m going to write about the amazing abilities of silkworm cocoons to keep vaccines and antibiotics cool, even in areas of extreme summer heat. This could be a great boon to immunization programs in Africa and Southeast Asia. Stay tuned!


Sadja Greenwood MD back issues sadjascolumns.blogspot.com

What Is the Microbiome?


Writing in The New Yorker on Oct. 22nd, Michael Specter explains the amazing new discoveries about the bacteria, viruses and fungi that colonize our bodies and affect our health. His article, Germs are Us, starts out with a discussion of the bacterium Helicobacter pylori (H. Pylori), found in the stomach of half the people on earth. While on the one hand it is a principal cause of gastric and peptic ulcers, and is associated with an increased risk of stomach cancer, its longevity in the human species, at least 200,000 years, makes it likely that it also plays a positive role in human evolution. Specter explains that we are inhabited from birth (the birth canal, mother’s skin, other people, all our surroundings) with a hundred trillion or more microorganisms. These microbes are in our mouths, digestive tracts, and skin – some 10,000 bacterial species, with a weight of about 3 pounds. They help us digest our food, manufacture vitamins in the colon (biotin and Vitamin K), and help our immune systems prevent infections. While the genes we inherit play a role in our health and disease, so does the microbiome. The human body can be seen more as a ‘vast, highly mutable ecosystem …. than like an individual assembled from a rulebook of genetic instructions’. Streptococcus mutans, in the mouth, is a principal cause of tooth decay, releasing acid when we eat sugar. Dentists are working on a number of measures to control this bacterium, including chlorhexidine and xylitol chewing gum. The bacterium Lactobacillus sakei may be capable of warding off sinusitis; this bacterium is destroyed by antibiotics. While antibiotics are ‘the signature medical achievement of the 20th century, and have saved millions of lives’, there is a downside to their use in terms of our microbiome. People without H. Pylori in their gut seem to be more sensitive to allergens, and are more likely to have had asthma as children. Children born by C-section lack many microbes transferred in the birth canal. Research from Finland and Germany indicate that these children may have more allergies. There is also a strong relationship between the presence of H. Pylori and two stomach hormones that control appetite. Ghrelin induces eating, and leptin suppresses the appetite. People whose stomachs have H. pylori have less ghrelin after a meal and stop eating; people without it may not get the message to stop and become obese. The reason that animals (poultry, cows and pigs) fed with antibiotics gain weight faster may have more to do with this mechanism than with treatment of illness. About 40% of children treated with broad-spectrum antibiotics develop diarrhea – and treatment with a probiotic (good bacteria for the gut) may prevent this disease. About 10% of people carry a bacterium called Clostridium difficile (C. difficile), which is normally held in check by other bacteria in the gut. When given antibiotics, people with C. difficile can develop severe, life threatening diarrhea and gut inflammation. Researchers are now using a technique called fecal transplant, in which they take intestinal bacteria from healthy donors and place them in the patient’s intestines. Cures have occurred with this treatment when nothing else has worked.






Specter ends his article with cautionary advice on probiotics, which he considers over-advertised without backup research. In the future we may know more about beneficial bacteria, but at present he thinks there is insufficient knowledge to say which bacteria should be used. After reading this, I did a search of current medical research on the use of probiotics. There are considerable findings on the use of beneficial bacteria to decrease antibiotic induced diarrhea, in decreasing childhood allergy, in improving the outcome of patients undergoing surgery for colon cancer, in vaginal infections in women, in the management of adult-onset diabetes, and in many other areas. My own conclusion is that a daily probiotic capsule from a reputable supplement company, with or without the ingestion of high-quality unsweetened yogurt, can help to prevent many gastro-intestinal infections. Use antibiotics when they are needed for serious bacterial infections, but always be mindful of your own beneficial bacteria.


Sadja Greenwood M.D., MPH back issues on this blog

Go to Health: Evolution: Snuggle or Struggle?


Writing in the July 2012 issue of Scientific American, Martin Novak outlined the ways in which cooperation has operated to shape evolution. Novak is a professor of biology and mathematics at Harvard; he has looked at evolution in species from amoebas to zebras, and has found that cooperation, and selfless behavior, is a pervasive phenomenon. The view that competition, for resources, mates, prestige, and leadership has been the most important factor explaining survival is challenged by this view.






Novak looked at numerous species to illustrate his views, and identified 5 mechanisms for the evolution of cooperation.


1.Vampire bats will share their blood meal with one who lost out on a given day; bats remember who helped them and later return the favor. Novak calls this direct reciprocity.


2. Neighbors, or friends in a social network, tend to help one another, so in a population with groups of cooperators, clusters develop that can prevail in competition with those who don’t cooperate. Novak calls this ‘spacial selection’.


3. Kin selection occurs when individuals make sacrifices for their relatives, who share their genes, still fostering the spread of these genes. J.B.S. Haldane, who first mentioned kin selection, wrote “I will jump in the river to save 2 brothers, or 8 cousins.”


4. Individuals may help another member of his (her) species based on the needy individual’s reputation. When the helper is in need, s/he may become the beneficiary of more help, having been seen to be generous. Novak calls this ‘indirect reciprocity’., and feels it is especially important in humans.


5. Finally individuals may perform selfless acts for the greater good of the group, as opposed to a single member. This is known as ‘group selection’. Lionesses within a pride will suckle each other’s young. Ants work together and sacrifice themselves to serve their colony. In his book The Descent of Man Darwin wrote that “a tribe including many members who….were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes, and this would be natural selection”.






Novak writes that cooperation has been a driving force in the evolution of life from the beginning, and that it has been particularly useful for humans because of our language. We can share information about each other – from our family members to strangers anywhere on earth. We are intensely interested in who does what to whom, and why. Reputation plays a major role in our decisions of how to position ourselves in the social network around us, what to do, what to support, what to buy.






Researchers looking at the need for cooperation to reduce climate change have found that people are more altruistic when they receive authoritative information about climate research, and they act more generously when allowed to make their contributions publicly rather than anonymously – when their reputation is on the line. When people receive a gas bill that compares their own consumption with the average household gas consumption in their neighborhood and that of the most efficient homes, they lower their consumption. How’s that for the interplay of competition and cooperation?






Our political parties both embrace concepts of individual struggle and cooperative unity, with Republicans leaning more toward individualism and competition, and Democrats more toward mutual help and cooperation. The balance is constantly shifting. In my home town, Bolinas, it seems that cooperation has been on the upswing for years. I am stunned by the work that people do locally for public good. We have the food programs at the Community Center, and at Mesa Park, Food for Families, the new Saturday lunch at St. Aidan’s Church, the free showers at Sam’s House, the free book store, and the immense amount of volunteer work to put on programs at the Community Center. Volunteer work for other local non-profits is outstanding – everyone I know is involved in one or another. Novak sums up his article with the following: “My work indicates that instead of opposing competition, cooperation has operated alongside it from the get-go to shape the evolution of life on earth, from the first cells to Homos Sapiens. Life is therefore not just a struggle for survival, - it is also, one might say, a snuggle for survival.”


Sadja Greenwood – back issues on this blog -->

Reduce your blood pressure with what?

Chocolate: Recent studies have shown that compounds in cocoa, called flavanols, reduce blood pressure via the formation of nitric oxide (NO) in the body.  NO is a signaling molecule in the body, which causes blood vessels to relax and open wider.  The people living on San Blas Island off Central America drink cocoa every day, as their main beverage, and have normal blood pressure regardless of age. Cocoa or chocolate has more protective flavanols if it has not been ‘Dutch processed’, so read labels carefully, and buy unsweetened cocoa powder (not Dutch-processed) or a dark chocolate bar with 70% cacao content.  You can sweeten the cocoa powder with xylitol, and do a favor to your teeth.  (Xylitol is a sweetener derived from plants that prevents bacteria from sticking to the teeth.) A recent report from the University of L’Aquila in Italy showed that elderly people with mild cognitive impairment showed improvement with cocoa flavanols, as well as reductions in their blood pressure.

Beets and beet juice:  numerous recent studies have shown that drinking beet juice lowers blood pressure and improves athletic performance.  The nitrates in beets (also found in leafy green vegetables) are translated into nitric oxide in the body.  Blood vessels widen, allowing for more blood flow.  In addition, beet juice reduces the amount of oxygen needed by muscles during activity.  For example, test subjects used less oxygen while walking, reducing the effort it took to walk by 12%.  This could be helpful for the elderly, and those recovering from heart and lung problems.  When competitive male cyclists were given beet juice before a timed trial, they were able to improve their racing times by 3%. Since in the world of elite sports a 3% improvement is big, athletes are turning to beet juice, as well as tart cherry juice, with enthusiasm.  Beet juice and freeze-dried beet juice powder are widely available on the Internet – although fairly costly. 

Celery and celery seed:  these foods have a long history in Indian Ayurvedic medicine to treat fluid retention, arthritis, gout and other problems. Chinese medicine also recommends celery to treat high blood pressure.  A substance called phthalide in celery acts as a diuretic, and apparently causes an equal loss of both sodium and potassium, which is helpful in maintaining sodium-potassium balance in the blood.  It also works by relaxing smooth muscles lining blood vessel walls.  A study done at the University of Chicago in the 1990s showed that a celery extract given to laboratory rats lowered their blood pressure 12-14%. In humans, a comparable daily ‘dose’ of celery would be about 4 stalks.  There are numerous individual reports of people using celery for blood pressure, but no further studies on this question.  Perhaps this is because it is hard to get funding for natural substances.   Celery seed, used as a spice, comes from a different plant related to edible celery.  Like celery, it acts as a diuretic, promoting loss of excess fluid in the body.  It is also used as an anti-inflammatory food. Chefs suggest that you add celery seeds to soups, tomato dishes, salads and eggs.   Light toasting brings out a sweet flavor. 

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If you take medicines to bring down your blood pressure, don’t stop them.  Chocolate, beet juice and celery may help, but should be factored in gradually.  Daily exercise and the DASH Diet are also essential.  Talk to your doctor about your plans!

Sadja Greenwood, MD    back issues on this blog

HPV – Who Knew All it Could Do?

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HPV – the Human Papilloma Virus – has been known for years to be the main cause of cervical cancer in women. There are over 40 types of HPV that are transmitted by direct skin to skin contact during vaginal, anal and oral sex, and most do not cause disease.  However, infection with certain viral types,  mainly but not exclusively  HPV 16 and 18, can cause cervical cancer if not treated. This is why the Pap test is so important for women who are or have been sexually active, with men or with women.  The Pap test is a procedure in which cells are scraped from the cervix and looked at under a microscope. The Pap test can detect abnormal cells before they become cancerous, and early treatment in the doctor’s office can get rid of the problem. However, some women don’t know about the need for regular pelvic exams, or can’t afford them. There were 4,200 deaths from cervical cancer in the US last year.  Cervical cancer is a very serious problem in developing countries which cannot afford to do Pap screening. 

Some subtypes of HPV can also cause cancers of the vulva, penis, anus and the mouth and throat.  Sexually transmitted HPV type 16 causes about 85% of anal cancers according to the National Cancer Institute. The risk for anal cancer is much higher in gay and bisexual men than heterosexual men.  Women who have anal sex are also at greater risk.

Condoms, which help to prevent pregnancy and HIVAIDS, can prevent HPV infection by about 70% if used every time.  Skin to skin transmission can still occur outside of the condom.  Still  - condom use is important with new partners.   The good news is that most HPV infections are cleared by the immune system in a few years and never cause a problem.  However, some people don’t clear the virus, and their infections remain. 

In recent years there has been an increase of cancers of the throat and base of the tongue, caused by HPV 16.  Previously known risk factors for throat cancer included smoking and alcohol, but throat cancers are now seen in younger people who don’t smoke or abuse alcohol. Throat cancers from HPV are more commonly seen in men, but women are also affected.  Oral sex is considered to be a major predisposing factor.  The increase in throat cancer is considered serious, because it can be hard to detect early.

Since most people do have genital and oral sex, how can we view this threat and deal with it?  Prevention and early detection are vitally important.  This would include:

*consistent condom use with new partners, even with oral sex.  This may seem unlikely, especially for teenagers trying to do the right thing to avoid pregnancy.  However, they should be informed about the problem.

*Make sure your children get the HPV vaccine, Gardasil or Cervarix – given in 3 shots over 6 months.  Both are effective in preventing infections that cause cervical cancer.  Gardasil is believed to prevent more HPV types, those that cause cancer of the anus, vulva and vagina.  HPV vaccination is recommended by the Centers for Disease Control for 11 and 12 year old girls, and girls and women age 13 through 26 who have not been vaccinated.  Gardasil has been found to be safe and effective for males age 9-26.  Vaccinating a boy with Gardasil will help his partners, and also help him to prevent oral cancer.  The cost of the vaccine is about $130 per dose - $390 for the series.  Most health insurance plans cover the cost, and the Vaccines for Children program may be able to help.

*Pap tests are still important for women, even if vaccinated, because the vaccines do not prevent about 30% of HPV types that can cause cervical cancer.

*Being in a faithful relationship with one partner, limiting the number of sex partners, and choosing a partner with few prior sex partners can be helpful.   However, it is not always possible to know if a partner or oneself is currently infected with HPV. 

*Early detection of cervical, vaginal, vulvar and anal cancer can be done by regular medical examinations, self exams, and alertness to anything that feels like a persistent sore or abnormal growth. 

*Early detection of cancers of the mouth and throat can be done by regular visits to the dentist and dental hygienist, who should look for abnormalities in the mouth and throat, including hidden areas at the back of the tongue.   Everyone should be aware of symptoms such as a persistent sore throat or mouth sore, a feeling of a mass in the throat, a lump in the neck, or difficulty swallowing.  

Check it out!

* Keep your immune system strong by getting enough sleep, exercising moderately, eating healthy food (lots of vegetables!), and avoiding tobacco, dangerous drugs, and excess alcohol.

Our venerable sage Ben Franklin told us:  An ounce of prevention is worth a pound of cure.  Let’s follow his advice. 

Sadja Greenwood, M.D., MPH  back issues on this blog

Arsenic in Rice?

Arsenic is a chemical element found in water, soil and air. For this reason, it is inevitably found in some foods. Human activities have added arsenic to the environment, through burning coal, oil, gasoline and wood, and through the use of arsenic compounds in pesticides, herbicides and wood preservatives. The Food and Drug Administration (FDA) monitors foods in our diet; it has analyzed arsenic levels in rice for 20 years, and has not found evidence of change in arsenic levels. However, researchers are now better able to measure whether existing levels represent more or less toxic forms of the element. It plans to complete its analysis of about 1,200 rice products (rice milk, rice cakes, infant cereal, etc) by the end of the year, and to issue guidelines.

Meanwhile, Consumer Reports, published by Consumers Union, has stated that its tests of more than 60 samples of rice and rice products found inorganic arsenic, a probable human carcinogen, in most samples. Earlier this year, they had found worrisome levels of arsenic in apple and grape juices, and called on the FDA to set limits for arsenic in these juices. They are now asking the FDA to set limits for arsenic in rice.

Consumer Reports’ study found:
*White rice grown in Arkansas, Missouri, Louisiana and Texas had higher arsenic levels than samples from California, India, and Thailand.
*Brown rice had higher levels than white rice, comparing rice from within a tested brand.
*Infant rice cereals and drink products contained worrisome levels of arsenic.
*Groups who rely on rice as a staple, such as some Asians and Hispanics, were found to have higher arsenic levels.

Rice grown in Texas, Louisiana and other gulf coast states have high levels of arsenic because of cotton growing in times past. Arsenic pesticides were used to control the boll weevil. California rice, and Asian rice have considerably lower levels.

Consumer Reports advises that children under 5 not be given rice drinks daily. Similar advice has been given in the United Kingdom.

Consumer Reports has asked the FDA to ban the feeding of arsenic containing drugs to animals (used for growth promotion and disease prevention). The manure of these animals contains arsenic, which can be used to fertilize food crops. It also asked for a phase out of arsenic containing pesticides.

Philip Landrigan, an epidemiologist, author and pediatrician at New York’s Mt. Sinai School of Medicine, suggests that pregnant women and babies avoid rice, or use only small amounts of California rice, or switch to other grains, such as oats or barley.

Arsenic has been implicated as a cause of skin cancer (non-melanoma), and is also related to cancers of the liver, lung, kidney and bladder. The evidence for this comes from studies in Taiwan, where well water contains high amounts of arsenic. The same is true in Bangladesh – tube wells drilled to protect the population from bacterial diarrheal disease have been found to have high levels of arsenic. This is a very serious situation in parts of India as well. Current remedial efforts include digging very deep wells, where water may have lower arsenic levels.

What can you do about arsenic in food and water? There is virtually no arsenic in Bolinas water. Call your local water department to find levels if you live elsewhere. Avoid apple and grape juice unless it is organic – even then, it’s better to eat the whole fruit. Avoid chicken, unless it is organic. Eat California rice, but don’t make it your everyday staple. Try almond milk if you usually drink rice milk. If you are avoiding gluten, try millet as a rice substitute. Millet should be rinsed first, and cooks in 20 minutes. You can make it very tasty by cooking it with onions, garlic, chopped nuts, and spices. When cooking, I always think of chef Rebecca Katz’ suggestion: FASS. F stands for a bit of fat, such as olive oil. A stands for acid – meaning a little something sour, like a squeeze of lemon. S stands for sweet – a drop of maple syrup, or pomegranate juice, or some frozen corn. S stands for salty – a pinch of salt. Put this in every dish, and you’ll love the result!

Sadja Greenwood, MD, MPH see more on this blog

What Are the Benefits of Organic Food?

A recent study from Stanford University looked at 17 studies comparing people who ate organic or conventional diets, and 223 studies comparing the bacterial, fungal or pesticide contamination of such foods. There were no long-term studies of health outcomes between the two diets in their analysis. The studies showed no consistent differences in the vitamin content of organic products, although there were higher levels of omega-3 fatty acids in organic milk. The study did find that organic produce had a 30% lower risk of pesticide contamination, but the pesticide levels in all food generally fell within the allowable safety limits. They found that children on organic diets had lower levels of pesticide residues in their urine, and organic chicken and pork reduced exposure to antibiotic resistant bacteria, but the clinical significance of all these findings were found to be unclear.

Many people have been confused by these findings from Stanford. Is organic food worth the extra money? Charles Benbrook, a professor at Washington State University’s Center for Sustaining Agriculture and Natural Resources, wrote a compelling answer in the October issue of Nutrition Action Healthletter. Benbrook has worked for the National Academy of Sciences, and consults for The Organic Center. He says that 60% of studies do show a higher nutrient content in organic foods, especially when the comparison is between fruits and vegetable grown in similar locations. The Stanford study did not consistently make such comparisons.

A recent study of tomatoes in Spain showed that organic tomatoes had twice the antioxidant levels as conventional tomatoes. There are two reasons for this. Organic plants have to fend off a range of insects, so they develop more defensive compounds that also keep us healthy. Conventional crops are produced with large amounts of nitrogen fertilizer, which drives up yields and fruit or leaf size, but dilutes the levels of vitamins, minerals and antioxidants.

Contaminants that cause food poisoning can grow more readily in conventional fields, because of extra nitrogen, and the lesser microbial diversity due to pesticide use. In organic fields there is more microbial biodiversity, so pathogens may not last as long or become as numerous.

Organic foods may not be pesticide free, because of traces blown in from conventional fields. However, pesticide levels are markedly lower. Benbrook has devised a scoring system, the Dietary Risk Index (DRI) that measures the number of different pesticide residues and their levels. Looking at organic versus conventional strawberries, blueberries, apples, grapes, nectarines, peaches and pears grown in the US, the DRI was 3 for organics, versus 24 for conventional fruits. Imported conventional fruits from Chile and Argentina have much higher DRIs than those grown in the US, because of more stringent regulations of pesticide use in the US.

According to Professor Benbrook, there is compelling evidence that low level exposure to organophosphate insecticides in food are contributing to neurologic and developmental problems in children, such as lowered IQ. Lead exposure was found to be most harmful in a Harvard study, followed by organophosphate pesticides and methylmercury. The most compelling evidence of harm comes from the insecticide chlorpyrifos, which has been banned by the EPA for home use, but is still permitted in agriculture. Its level in pregnant farmworkers correlated with lower IQs in their children. When researchers at Emory University in Atlanta gave children organic fruits and vegetables, chlorpyrifos levels fell to almost undetectable levels in their urine in 5 days. Chlorpyrifos is made by Dow Chemical. A coalition of farmworker and advocacy groups filed a lawsuit against the EPA in 2007 seeking to ban the use of chlorpyrifos; the suit is still pending.

Professor Benbrook thinks that the most important dietary change we can make is to eat more fruits and vegetables, and less bad fat, added sugar and processed food. I’m going to add – eat with the seasons, so that you avoid imported produce with its higher levels of pesticides. The second most important is – of course - to eat organic produce and organic grains. If you can afford it, this is your most important step.

Subscribe to the Nutrition Action Healthletter if you want to keep up with the science of nutrition in an easy, readable format. It’s easy to find the address on-line, and 10 issues cost only $10!

Finally – let always give thanks to our local organic farmers, and to the Bolinas People’s store with its daily array of luscious, healthy food!

Sadja Greenwood MD back issues at on this blog

Olive Oil - What are its advantages?

New studies show some surprising benefits for olive oil, including a possible protective effect on bone. Spanish research, to be published in the October issue of the Journal of Clinical Endocrinology and Metabolism, shows that consumption of a Mediterranean diet enriched with olive oil is associated with increased serum osteocalcin and other bone formation markers. Osteocalcin is produced by bone cells called osteoblasts, and is used as a marker for bone formation. Prior to this study, it had been noted that the incidence of osteoporosis in Europe was lower in the Mediterranean basin. All subjects in this study were instructed to eat a Mediterranean diet, rich in fruits and vegetables, lean protein from fish, poultry, and beans, and whole grains instead of white flour bread and pasta. Olive oil was their added fat.

Another Spanish study in 2010 showed that the phenolic compounds in extra virgin olive oil change how genes function. Phenols are chemical compounds found in plants that have many unique properties. In conjunction with a Mediterranean diet, genes related to atherosclerosis were down regulated, and there was a positive impact on oxidation of fats and DNA, insulin resistance, inflammation, carcinogenesis and tumor suppression. Atherosclerosis is a disorder that occurs when fat, cholesterol and other substances build up in the walls of arteries and form hard structures called plaques. This diminishes blood flow and can lead to heart attack and stroke.

Breast cancer risk may also be modified by virgin olive oil. Spanish scientists at the University of Barcelona decoded the signals within breast tumor cells activated by olive oil, concluding that benefits include decrease in activity of an oncogene, and stimulation of tumor cell death. An oncogene is a gene that has the potential to cause cancer, if activated by mutations in another gene or certain environmental factors. Olive oil also showed ability to prevent DNA damage. Corn oil and some other vegetable oils high in polyunsaturated fatty acids, can increase the aggressiveness of cancers.

Virgin olive oil is oil produced by crushing olives mechanically, with no chemical treatment. It has an acidity of less than 1.5%. Extra virgin olive oil comes from virgin olive oil and is lower in acidity (less than 0.8%) and is judged to have the best taste. Virgin olive oils contain the highest levels of phenolic compounds and anti-oxidants that have been linked with better health.

Using olive oil or canola oil on your salads will give you the best absorption of carotenes from colorful vegetables, according to a new study from Purdue University. Low fat and non-fat salad dressings resulted in minimal carotene absorption. Carotenes are pigments that occur in vegetables and fruits and have multiple healthy properties. Avocado is another healthy fat that enhances carotene absorption. If you do use canola oil, make sure that it is organic. Otherwise you will be using genetically modified canola that may be high in pesticides and herbicides, as ‘superweeds’ and resistant insects have evolved to make the application of Roundup less effective. More spraying is necessary.

Your vote in support of Proposition 37 in November will help to ensure that genetically modified food products are labeled in California. This is a huge issue for food companies, who have raised millions against the proposition. Stay tuned, and read the arguments on your ballot carefully.

Sadja Greenwood, MD, MPH back issues on this blog

Dr. Oz on Longevity

Who is Dr. Oz? Mehmet Oz is a cardiac surgeon from Columbia University who has become a popular author and energetic television promoter for getting fit, losing weight and staying healthy. His books, co-authored with Michael Roizen, include You: The Owner’s Manual, and You: On a Diet; they explain the workings of the body and its organs clearly and simply. Dr. Oz’s television program (weekdays at 4, channel 2)) shows a charismatic doc in surgical scrubs promoting a great variety of techniques for staying fit and losing weight, along with numerous products to help you on your way. He is fun to watch. Here are his 10 simple habits that could help you live to 100, with my comments tacked on.

1. Add red foods to your diet. Oz suggests red cabbage, as cruciferous vegetables help to protect against cancer, and beet juice, with nitrates that relax blood vessels. I will add that beets are a great food because the nitrates in beets, also found in green leafy vegetables, are a source of nitric oxide in the body, which dilates blood vessels, improves blood flow, and lowers blood pressure. Other red foods are tomatoes and watermelon, high in the beneficial antioxidant lycopene, and red wine and red grapes, with resveratrol. Resveratrol is currently under study as a substance with anti-inflammatory properties and cardiovascular benefits. It is also found in peanuts and chocolate. I think it is wiser to get resveratrol in foods than in supplements.

2. Black tea – have a cup daily to boost your survival after a heart attack. I will add that research from The Netherlands showed that drinking 3-6 cups of tea daily was associated with a 45% reduced risk of death from heart disease.

3.Dial one phone number from memory every day. Oz advises using your memory rather than relying on your devices. I will add that there are many ways to exercise your memory, including memorizing new words, school work, a new language, poems, music and songs. Work on this while you walk or work out, and just before sleep at night.

4. Use the first stall in a public restroom to prevent getting sick. Oz says the first stall is used less often, as people want more privacy, and it contains the lowest bacteria counts. I’ll add that washing your hands is also very important. Taking a daily probiotic is vital to amp up your immune system (the majority of your immune tissue lines your gut). Vitamin D also helps to prevent respiratory illness.

5. Take two steps at a time when you climb stairs. If you can’t do that, try walking up the stairs twice. I’ll add that keeping your legs strong is important for balance as well as for walking and other sports. If you don’t have stairs at home, you can get step-up blocks or risers at a sporting goods store or on the internet. Resistance training at home or in a gym is really important.

6. Stretch after a hot shower to prevent pain – stretching is best when muscles are warm; stretching improves posture and prevents muscle soreness. Oz suggests raising your arms, bending forward to the right slowly, and then to the left. I would add that that any other standing stretching exercise you like can also be helpful.

7. Hold your breath: take a deep breath, hold for 10 seconds, and then slowly exhale through pursed lips. I think this is a wonderful daily practice, not only for singers and wind instrument players but for all of us who breathe. Yoga classes emphasize many kinds of breathing, to stimulate and relax the body.

8. Do the Reverse Warrior Pose: For this exercise, I suggest you watch Yoga Reverse Warrior Pose by Jennifer Kostel on YouTube. Her presentation is simple and not extreme. Do it on both sides. It promotes balance, flexibility and strength.

9.Chew your food 20 times – slowing down your eating will increase your enjoyment of food, and help to prevent diabetes. If this is hard, put down your fork between bites. I have found the chewing practice to be extremely helpful in preventing reflux pain at midnight. By extra chewing, you start the digestive process (with digestive enzymes in saliva) and make less grinding work for your stomach. It can empty faster. I’m a convert.

10. Cut your cravings in half to cut calories. When confronted with ‘must have’ chips or cookies, Dr. Oz wants you to ‘halve them’. Put the second half away and out of sight. My thinking is that this works well for some people, but others with food addictions need to have the tempting foods out of the house. Don’t shop when you are hungry, and don’t buy foods you will binge on.

Dr. Oz is a television wonder, on a nationwide mission to get us slimmer and more fit. I know it’s daytime TV, but watch him if you have a chance.

Sadja Greenwood, MD, MPH back issues at on this blog