Last month, I described the problem of obesity and the role of food-based dietary guidelines (FBDGs) in advising people about what types of foods to eat, which to avoid and the proportions that are best. While many of the privileged people in the world eat too much and are overweight, 821 million people in the world are suffering from hunger, according to an estimate made by the Food and Agriculture Organization (FAO) of the UN in 20171. Suboptimal diets were responsible for more deaths than any other single cause, including smoking tobacco2.
I also listed the similarities shared by FBDGs in different countries. There are common themes in all of them: consume foods in the proper proportions, eat lots of fruits and vegetables as well as limit the intake of sugar, fat and salt3. The messages in FBDGs are augmented by recommended daily allowances (RDAs) that tell how much fat, fatty acids, carbohydrates, cholesterol, protein, amino acids, vitamins and minerals and total Calories (energy) that one should consume. Also, the USDA publishes a Nutrient Database that lists the nutrient levels in hundreds of foods4. However, the RDAs are “estimates of the minimum daily average dietary intake level that meets the nutrient requirements of nearly all (97 to 98 percent) healthy individuals” 5. So, the Food and Nutrition Board of the IOM included an Acceptable Minimum Distribution Range (AMDR), as well as tolerable upper intake level in their recommendations5,6. The AMDR reflects optimal intake of nutrients, instead of just the minimum requirements6. One of the things that all dietary guidelines have in common is that they try to use the best scientific evidence available, but they are also influenced by economic, political and sociological factors7. Government organizations may try to put interests of the public first, but the part of the public that controls most of the money has a huge influence on what governments are even allowed to consider to be valid evidence. This is important because the guidelines will affect policies on agriculture and food assistance programs, as well as nutrition in schools, prisons, hospitals and nursing homes. It will also affect the messages that health care professionals and the media will give to the public. Naturally, the messages that governments give depend partly on the culture and traditions of their people.
So, this second part of this story in this month’s article will describe differences between FBDGs from different countries. The story starts with a description of the history of FBDGs since they started in 1916. They were affected by poor evidence and an incomplete understanding of nutrition. When poor evidence is used to guide public policy decisions it can contribute to the growing burden of preventable, chronic diseases7. For example, the misleading results of animal studies led the USDA to recommend a low-fat diet in the 1970s. As science and medicine advanced, guidelines improved7. However, governments try to maintain a balance between keeping the message understandable and concise and the demand by a portion of society for more details and better advice. So, this month’s article will also discuss issues that are not covered in few (if any) FBDGs, such as the importance of the timing of meals and not all calories are the same.
Historical Differences in Food Based Dietary Guidelines (FBDGs)
In the beginning years (1916 to the 1930s), the US Guidelines were called “Food for Young Children” and “How to Select Foods” 8. The focus was on protective foods that contained minerals and vitamins needed for children’s growth and well-being. In the 1940s, “A Selective Guide to Good Eating” described a foundation for nutrient adequacy. It started the practice of using an image to summarize key concepts. It showed seven food groups in a colorful circle, but it was considered to be too complex. From 1956 to the 1970s, the FBDG was entitled “Food for Fitness, A Daily Food Guide” (The basic four). It reduced the number of food groups to four (milk, vegetable/fruit, meat and bread/cereal). It did not include advice about appropriate fats, sugars or caloric intake. In 1979, the “Hassle-Free Daily Food Guide” was issued after dietary goals were released in 1977. The basic four food groups remained, but a fifth group was added: fats, sweets and alcohol. This was done to highlight the need to limit their consumption. In 1984, a “Food Wheel: A Pattern for Daily Food Choices” appeared. It introduced the concept of moderating one’s intake. Daily amounts of each of the five food groups were provided. In 1992, the “Food Guide Pyramid” appeared. It showed an image of a pyramid. At the top were fats, oils and sweets, being added to the five food groups below it:
- bread, cereal, rice & pasta
- milk, yogurt & cheese
- meat, poultry, fish, dry beans, eggs & nuts.
Each group had a recommended number of servings. In 2005, “MyPyramid Food Guidance System” updated the food guide pyramid with daily limits for people who have different levels of physical activity and energy needs. It added a band for oils and stressed the importance of physical activity. The illustration shows the concepts of variety, moderation and proportion. In 2011, the pyramid became a plate in “MyPlate”. It used an image of a food circle instead of a pyramid. The different shape attracted attention with a new visual cue to remind us to eat healthy, without providing a specific message. The basic food groups were:
- protein foods
Each of them had subgroups and specific recommendations, like this in the dairy group: “Cream, sour cream and cream cheese are not included due to their low calcium content”. In the group called protein foods, people are advised that “Meats and poultry should be lean or low-fat and nuts should be unsalted” 8.
Differences in Dietary Guidelines Issues by Different Nations
Even though all FBDGs indicate that they apply to the general population, 46% qualify this by saying “healthy” population, while 13% say “adult” population” 3. About half (52%) of the FBDGs indicate that their guidelines apply to people over two years of age. Most countries (87%) also publish a food guide (picture). Most of these guides say that the consumption of some foods should be limited (sugars, sweets, fats and oils), but many emphasize the importance of eating unsaturated, polyunsaturated and/or omega-3 fats (or fatty acids). Excluding fats, oils, sugars and sweets, a little over half of the countries list five food groups: starchy staples (complex carbohydrates), fruits, vegetables, dairy and other protein-containing foods. Many other countries just list four food groups by combining fruits and vegetables into one group. Some don’t list dairy as a separate group. They just list three groups: starchy staples, fruits and vegetables and “protein foods” 3.
Few nations specify the amount of starchy foods or carbohydrates that one should consume, but some specifically encourage eating whole grains (as opposed to white, bleached flour or rice) 3. They also differ in their recommendations about potatoes. Germany recommends “Eat plenty of cereals, preferably whole grain and potatoes”. Not all FBDGs use the word “protein”, but 74% include messages about specific foods like meat (53%), poultry (29%), fish (58%), eggs (31%), legumes (41%), dairy (%) and nuts or seeds (8%). Kenya even mentions insects as a source of protein. Many countries recommend eating lean meat or suggest cutting the fat off the meat. Some (34%) have a positive message about eating fish, while 23% suggest moderating or limiting meat consumption (especially red meat). There are also key messages about legumes (beans, peas, lentils and nuts). Dairy products are mentioned separately in 59% of the FBDGs. However, the Chinese FBDG combines soy and dairy into one group. Most countries (89%) say to limit fat consumption, but less than half (44%) say anything about the quality of the fats (unsaturated vs saturated fats). The North American countries indicate that healthy fats (unsaturated and omega-3 fats) should be consumed regularly, but only 18% of all countries in the world state that. Even though most nations encourage eating many fresh fruits and vegetables, some also recommend that they be locally produced. Some (19%) recommend eating a variety or a specific color, such as green leafy vegetables, orange fruits and/or berries. However, only 35% of the Asian countries specifically mention eating fruits and vegetables daily, while 71% of African, 79% of European and 81% of Caribbean countries do so. On the other hand, some countries recommend limiting fruit juice to no more than one serving per day3. This is good advice for sweetened juices, like apple and orange, as opposed to unsweetened juices that naturally contain very little sugar (like elderberry juice).
One serious and quite interesting difference is the recommendations on alcohol9,10. The FBDG from the USA says, “If alcohol is consumed, it should be consumed in moderation – up to one drink per day for women and up to two drinks per day for men – and only by adults of legal drinking age”. One alcoholic drink-equivalent is described as containing 14 g (0.6 fl oz) of pure alcohol. There are also many circumstances in which individuals should not drink, such as during pregnancy” 9. Belgium-Flanders recommends, “Spread your consumption over several days during the week. Have a few alcohol-free days”. Estonia recommends, “Do not save up on daily intake to binge later”. Cyprus recommends, “Prefer red wine”. Portugal recommends “Consume in moderation”. Most countries recommend limiting alcohol consumption. However, Poland recommends, “Do not drink alcohol”. The Netherlands also recommends not drinking alcohol and adds the statement, “Binge drinking is harmful”. Spain indicated, “Alcohol consumption is not recommended” 10.
Other Important Factors in the Obesity Epidemic Not Covered in FBDGs
Biology, environment and behavior affect body mass index (BMI) and obesity, even though many FBDGs don’t address all these factors11. Biological factors include not just diet, but also genetics, the gut-brain axis, prenatal conditions, pregnancy, menopause, the status of the neuroendocrine immune system, medications, physical disabilities, the quality of the gut microbiome and viruses. Environmental factors include the abundance of food, built environments (urban sprawl, less walking, fast food culture), socio-economic status, culture, social bias and environmental pollutants. This includes bisphenol A (BPA), phthalate esters, and organotin compounds like tributyltin (TBT) and triphenyltin (TPT). Behavioral factors include excess caloric intake, eating patterns, sedentary lifestyle and insufficient sleep11.
One of the most important of these factors is genetics. For example, the risk of developing childhood-onset, type-1 diabetes is higher if a family member has (or had) the disease. On the other hand, even under obesity-promoting conditions, not everyone becomes obese. This can be caused by environment (psychosocial, cultural and economic factors), genetics and epigenetics. There are also some rare gene defects that can cause childhood-onset obesity12. However, it’s not just the genes that are in our human Eukaryotic cells that are important. The genes in the bacteria in our gut (gut microbiome) also affect one’s risk for becoming overweight or obese. Consuming fresh fruits and vegetables, as well as whole grains helps to build a healthy gut microbiome – especially if you don’t eat meat13. When your gut is populated by healthy bacteria, they can convert dietary fiber to short chain fatty acids (acetate, propionate and butyrate) that help decrease one’s abdominal fat, while increasing the level of hormones that help to control the appetite14. However, recent research has shown that when one of these short chain fatty acids, propionate, is consumed in one’s food (as opposed to being produced by bacteria in the gut), it can lead to type-2 diabetes15. That is, calcium propionate is a preservative that is often added to cheeses and baked goods to prevent the growth of molds. Even though it is generally regarded as safe (GRAS), it can lead to insulin resistance, obesity and an imbalance in metabolism when it enters the circulation15, as opposed to staying in the gut. This research is so new that no FBDGs mention it.
FBDGs also don’t mention obesogens - environmental pollutants that can help cause obesity16,17. They are dietary, pharmaceutical and industrial chemicals that may alter metabolic processes and predispose some people to gain weight16. That is, “Disrupted energy balance does not account for the obesity epidemic” 17. The obesogen hypothesis states that certain environmental chemicals (obesogens) promote obesity by increasing the production of fat cells (adipocytes) by altering metabolic set points or changing the hormonal regulation of appetite and satiety. Many obesogens (like BPA, TBT and TPT) are endocrine disruptors that are in many commonly used products, from fungicides to food packaging17. Unfortunately, the interests of the rich, industry and stock holders seem to be more important than the rest of the public at times. The companies that make and market these obesogens maximize profit, while harming public health. Obesity has been estimated to add an additional $200 billion annually to the healthcare budget in the USA. These are due to the cost of treating the comorbidities of obesity: cardiovascular diseases, dyslipidemia, type-2 diabetes, liver disease, neurodegenerative diseases, cancer and reproductive diseases17.
Few FBDGs mention the importance of the timing of our meals, even though this is a key factor. As mentioned before, adipose tissue does much more than just store fat. It is also affected by the daily circadian rhythm15,18,19. It is better to consume high energy meals in the morning or in the middle of the day, when adipose cells will mobilize fat rather than store it18. That is, disrupting the daily circadian rhythms seriously affects metabolism and homeostasis15. The central clock (or pacemaker) in the brain oscillates and synchronizes the network of peripheral clocks that are in all tissues and cells. Circadian clocks are affected by not just the day/night cycle, but also energy intake and the timing of meals. Chronic disruption of the circadian rhythm can lead to metabolic syndrome, cardiovascular diseases and type-2 diabetes15. Having a regular pattern of eating with more in the morning, eating no more than three times a day and regular fasting can reduce inflammation, improve circadian rhythmicity and the gut microbiome as well as increase improve resistance to stress19. In one study, eating only one or two meals a day was associated with a lower BMI. The longer the overnight fast, the lower the BMI. It’s also better to consume more Calories earlier in the day. However, this may not be desirable in societies where this is not popular. Since eating is usually a social event, it can be important to follow the norms of society to be accepted and to avoid loneliness, which is unhealthy19.
Another factor in timing is when people eat while watching TV20,22. Spending too much time watching TV can increase sedentary behavior and affect what we eat without thinking37. Commercials on TV can entice people (especially children) to eat sweetened beverages as well as processed meats and highly processed foods that are loaded with sugar, saturated fats, and trans fats20. Watching TV replaces physical activity and exposes people to advertisements for sweetened beverages as well as foods that not are only high in Calories and lacking important nutrients, but also stimulate the appetite21.
Sweetened beverages and excess alcohol consumption are especially harmful, even though attitudes vary in different countries. For example, some people think that drinking alcohol with a meal and even afterwards is healthy22,23. There is even a word for any alcoholic drink that is served after a meal to help with digestion – a digestif39. Claims about the benefits or otherwise of drinking alcoholic beverages with food, especially high fat and high energy meals such as cheese fondue, are conflicting23. In Switzerland, some traditionalists demand that white wine is drunk with this classic winter dish, whereas others insist that only black tea is appropriate. The debate continues after dinner as to whether a shot of “spirits” will promote digestion and digestive comfort. The evidence base is weak. However, grave concerns about the correct choice of beverage seem to exist23. For example, a questionnaire indicated that respondents anticipated severe side effects from drinking Coca Cola with fondue, ranging from dyspepsia to death24.
However, the safest level of drinking is none25. In 2016, drinking alcohol led to 2.8 million deaths and was the leading cause of disability and premature death in people 15-49 years of age42. At the same time, sweetened beverages not only lead to obesity, but are also consumed as part of hedonistic eating (eating simply for pleasure). Sugar-sweetened beverages increase mortality (decrease lifespan) 26. Red meat – especially highly processed meats (like hot dogs, bacon and ham in the USA) is especially deadly27. There is a higher risk of all-cause and cardiovascular disease mortality (heart attacks and stroke) in people who consume even small amounts of red and processed meat. Similar results have been seen before in populations that eat moderate to high levels of meat27. People who ate the most meat in a recent study had the highest risk of heart failure28. However, it will not be easy to get this message across to the public. Processed meats are economically important because consumers demand them and because these products use the parts of the animal that have lower value, making it more profitable29. According the Food and Agriculture Organization (FAO) of the UN, "The raw meat materials used for precooked-cooked products are lower-grade muscle trimmings, fatty tissues, head meat, animal feet, animal skin, blood, liver and other edible slaughter by-products"29.
Culture is also an important factor30. Meat consumption has strong links to societies’ concepts of masculinity, prosperity and self-indulgence. Misogynistic men think of girls, women and the environment as commodities to be used and then discarded also damage the environment. Men who conform more to masculine standards (be tough, stoic, dominant, daring and in control) are more likely to assault and rape women, consider suicide, take risks with sexual partners and when driving, avoid seeking help and refrain from active fathering. The violence that such men inflict on their children often produces violent men30. “This has many outcomes that are disastrous for the individual, for society and for nature. They will progressively acquire a phenomenal variety of dysfunctional behaviours, including some that are violent towards themselves, others and/or the Earth” 31.
However, scientific articles are attempting to inform the public32. A machine-learning algorithm was used to integrate blood chemistry, dietary habits, anthropometrics (body size and shape), physical activity and gut microbiota to predict personalized postprandial (after meal) glycemic response (blood glucose). The predictions were validated by a blinded randomized and controlled dietary intervention of the subjects. It showed that the glycemic response improved and the gut microbiome changed to a healthier state when they followed the advice given to them32. So, there is very useful information that is available to the public in the scientific literature.
Continuous Improvement Through Research
Advice on diet will continue to improve as more research is done – especially when systems thinking is used. We are not machines. We are individuals who need personalized medicine and personalized diets33-36. In a recent study of an 800-person cohort (group of subjects), much interpersonal variety was seen in how the concentration of blood sugar (glucose) was affected by eating identical meals35. This work is continuing as researchers use artificial intelligence and deep learning to analyze huge sets of data and guide individuals in choosing an optimal personalized diet36. So, we are not machines living in isolation. Society, the environment and even a close intimate relationship affect our gut microbiome and health37.
An Underlying Problem: Systemic Violence
Violence and misuse of power is a systemic problem that affects our health and the availability of societies to care for their most precious assets – our women and children. In a brilliant article, Robert J Burrowes described the link between violence, self-obsession, self-pity and environmental destruction37. “Archetype perpetrators of violence have an intense fear of knowing the truth”. “They will manipulate the perceptions of others to obscure the truth”. They “will lie prodigiously in defense of their illusion”. They “invariably fear those victims who resist their violence, usually perceive resistance to their violence as ‘morally wrong’ and perceive any resistance to their violence (including justifiably expressed anger and/or explicitly nonviolent resistance) as ‘violent’. Some perpetrators of violence are full of self-obsession and self-pity”. Human violence can be represented as an iceberg with three tips: war, exploitation of the Third World and environmental destruction. Beneath the surface is the bulk of the iceberg – represented by violence. Governments devote resources to military, police, legal systems and prison systems so they can perpetuate violence. They define enemies and criminals as legitimized victims. About $2 billion are spent each day on military violence. “If we do not break our addiction to violence, it will destroy us all” 37.
In conclusion, government agencies have been issuing dietary guidelines for decades. Food-based dietary guidelines (FBDGs) have been published in 90 different countries11. There are common themes in all of them: consume foods in the proper proportions, eat lots of fruits and vegetables as well as limit the intake of sugar, fat and salt11. FBDGs are different than recommended daily allowances (RDAs) that countries publish. RDAs tell how much fat, fatty acids, carbohydrates, cholesterol, protein, amino acids, vitamins and minerals and total Calories (energy) that one should consume. Also, the USDA publishes a Nutrient Database that lists the nutrient levels in hundreds of foods12. The FBDGs tell how much of each food group one should consume to obtain sufficient nutrition, while avoiding obesity. Still, hunger in the world continues to grow, as do the number people are overweight. Suboptimal diets were responsible for more deaths than any other single cause, including smoking tobacco7. In addition, switching to a primarily plant-based diet from a diet that includes unhealthy animal-based food (red meat and processed meat) is good for your health and for the environment. At the same time, highly processed foods, sweetened beverages, alcohol and environmental toxins, as well as the timing of meals and fasting affect the risk of becoming obese and suffering from NCDs. Even though much of the advice in the dietary guidelines apply to almost everyone, personalized diets are important – as is following recent research and technology. For example, artificial intelligence and deep learning are being used to analyze huge sets of data and guide individuals in choosing their optimal personalized diet35.
So, even though the dietary guidelines have changed since they were first issued in 1916, they were mostly based on the best evidence that was available at the time. As our understanding of nutrition improved, the advice in the guidelines also improved. So, science is often a continuous and iterative process. We seldom (if ever) have any final answers. We continuously improve in our attempts to learn how to live longer, healthier lives.
Some of my future articles will continue with this theme. We are continuing to learn more about how we age and whether aging is inevitable, or can be reversed. We are learning that aging can be slowed down. Scientists have recently found a way to predict accurately one’s biological age – as opposed to chronological age. So, my next article will describe how this is done by looking at epigenetics – the layer of control that exists above and beyond our genes (genetics). It will also describe a recent study which showed that aging was reversed in people when they were given a combination of human growth hormone, the dietary supplement dehydroepiandrosterone (DHEA) and the readily available prescription drug metformin, which has already been shown to increase lifespan (decrease mortality) by itself38.
1 Ayala, F. Parliamentarians of the World, Unite! The Call of Madrid: Zero Hunger by 2030 and the Alarm against the Epidemic of Obesity, Wall Street International, 9 December 2018.
2 World Health Organization. World Health Statistics 2016. Monitoring Health for the SDGs, Sustainable Development Goals, World Health Organization, Geneva, Switzerland, 2016.
3 Herford, A. et al. A Global Review of Food-Based Guidelines. American Society for Nutrition, Volume 10, pp. 590-605, 2019.
4 USDA. Food Composition Database, 2019.
5 Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids. Washington, DC, National Academy Press, 2005.
6 Wolfe, R.R. and Miller, S.L. The Recommended Dietary Allowance of Protein. Journal of the American Medical Association. Volume 299, pp. 2891-2893, 2008.
7 Zeraatkar, D. et al. Evidence Collection and Evaluation for the Development of Dietary Guidelines and Public Policy on Nutrition. Annual Reviews of Nutrition, Volume 39, pp. 227-247, 2019.
8 USDA, Center for Nutrition Policy and Promotion, A Brief History of USDA Food Guides, 2011.
9 USDA. Dietary Guidelines for Americans, 2015-2020, Eighth Edition, 2015.
10 EU Science Hub. Food-Based Dietary Guidelines in Europe, 2019.
11 Kadouth, H.C. and Acosta, A. Current Paradigms in the Etiology of Obesity. Techniques in Gastrointestinal Endoscopy, Volume 19, pp. 2-11, 2017.
12 Yanovski, S.Z. and Yanovski, J.A. Toward Precision Approaches for the Prevention and Treatment of Obesity. Journal of the American Medical Association, Volume 319, pp. 223-224, 2018.
13 Smith, R.E. Don’t Eat Meat. Save Yourself and Humanity. Wall Street International, October, 2018.
14 Smith, R.E. The Deep Ecology of the Human Body. EC Microbiology, Volume 9.6, pp. 224-230, 2017.
15 Tirosh, A. et al. The Short-Chain Fatty Acid Propionate Increases Glucagon and FABP4 Production, Impairing Insulin Action in Mice and Humans. Science Translational Medicine, Volume 11, Article eaav0120, 2019.
16 Holtcamp, W. Obesogens. An Environmental Link to Obesity. Environmental Health Perspectives, Volume 120, pp. A63-A68, 2012.
17 Heindel, J.J. and Blumberg, B. Environmental Obesogens: Mechanisms and Controversies. Annual Review of Pharmacology and Toxicology, Volume 59, pp. 89-106, 2019.
18 Garaulet, M. and Gómez-Abellán, P. Timing of Food Intake and Obesity: A Novel Association. Physiology & Behavior, Volume 134, pp. 44-50, 2014.
19 Paoli, A. et al. The Influence of Meal Frequency and Timing on Health in Humans: The Role of Fasting. Nutrients, Volume 11, Article 719, 2019.
20 Blass, E.M. et al. On the Road to Obesity: Television Viewing Increases Intake of High-Density Foods. Physiology & Behavior, Volume 88, 597-604, 2006.
21 Boulos, R. et al. ObesiTV: How Television Is Affecting the Obesity Epidemic. Physiology & Behavior, Volume 107, 146-153, 2012. 22 Zimmerman, E. How to Digest a Gigantic Meal. The Cut, Nov. 21, 2018.
23 Heinrich, H. et al. Effect on Gastric Function and Symptoms of Drinking Wine, Black Tea, or Schnapps with a Swiss Cheese Fondue: Randomised Controlled Crossover Trial. British Medical Journal, Volume 341, Article c6731, 2010.
24 Hill, L. and Wilder-Smith, C.H. Gastrointestinal Tolerability of Cheese Fondue and the Choice of Prandial Drink. Gastroenterology, Volume 116, Article G4364, 1999.
25 GBD Alcohol Contributors. Alcohol Use and Burden for 195 Countries and Territories: A Systematic Analysis for the Global Burden of Disease Study 2016. The Lancet, Volume 392, pp. 1015-1035, 2018.
26 Anderson, J.J et al. Sugar-Sweetened Beverages Intake Associates with All-Cause Mortality Independently of Other Dietary and Lifestyle Factors and Obesity. Proceedings of the Nutrition Society, Volume 78, Article E6, 2019.
27 Alshahrani, S.M. et al. Red and Processed Meat and Mortality in a Low Meat Intake Population. Nutrients, Volume 11, Article 622, 2019.
28 Cui, K. et al. Association between Intake of Red and Processed Meat and the Risk of Heart Failure: A Meta-Analysis. BMC Public Health. Volume 19, Article 354, 2019.
29 Wilde, P. et al. Legal Feasibility of US Government Policies to Reduce Cancer Risk by Reducing Intake of Processed Meat. The Milbank Quarterly, Volume 97, pp. 420-448, 2019.
30 Smith, R.E. The Myth of Gender Differences in Intelligence. Wall Street International, 24 August, 2019.
31 Burrowes, R.J. Why Do Some Men Rape?. Wall Street International, 8 Ocober, 2017.
32 Trumino, L. The Personalized Diet. Wall Street International, 13 June 2018.
33 Segal, E. et al. The Personalized Diet, Hachette Book Group, New York, 2017.
34 Zeevi, D. et al. Personalized Nutrition by Prediction of Glycemic Responses. Cell, Volume 163, pp. 1079-1094, 2015.
35 Topol, E. High-Performance Medicine: The Convergence of Human and Artificial Intelligence. Nature Medicine, Volume 25, pp. 44-56, 2019.
36 Kiecolt-Glaser, J. et al. Marriage and Gut (Microbiome) Feelings: Tracing Novel Dyadic Pathways to Accelerated Aging. Psychosomatic Medicine, 2018.
37 Smith, R.E. Metformin (Glucophage) May Extend Lifespan. Wall Street International, 24 August, 2018.
38 Burrowes, R.J. Why Violence?.