About two months ago, I did an interview with Jimmy Moore of the Livin' la Vida Low Carb internet empire. I hardly remember what we talked about, but I think it went well. I enjoyed Jimmy's pleasant and open-minded attitude. Head over to Jimmy's website and listen to the interview here.
I do recall making at least one mistake. When discussing heart attacks,I said "atrial fibrillation" when I meant "ventricular fibrillation".
In Search of Traditional Asian Diets
It's been difficult for me to find good information on Asian diets prior to modernization. Traditional Chinese, Taiwanese and Japanese diets are sometimes portrayed as consisting mostly of white rice, with vegetables and a bit of meat and soy, but I find that implausible. Rice doesn't grow everywhere, in part because it requires a tremendous amount of water. Removing all the bran was prohibitively labor-intensive before the introduction of modern machine milling. One hundred years ago, bran was partially removed by beating or grinding in a mortar and pestle, as it still is in parts of rural Asia today. Only the wealthy could afford true white rice.
Given the difficulty of growing rice in most places, and hand milling it, the modern widespread consumption of white rice in Asia must be a 20th century phenomenon, originating in the last 20-100 years depending on location. Therefore, white rice consumption does not predate the emergence of the "diseases of civilization" in Asia.
In the book Western Diseases: Their Emergence and Prevention, there are several accounts of traditional Asian diets I find interesting.
Taiwan in 1980
The staple constituent of the diet is polished white rice. Formerly in the poorer areas along the sea coast the staple diet was sweet potato, with small amounts of white rice added. Formerly in the mountains sweet potato, millet and taro were the staple foods. During the last 15 years, with the general economic development of the whole island, white polished rice has largely replaced other foods. There is almost universal disinclination to eat brown (unpolished) rice, because white rice is more palatable, it bears kudos, cooking is easier and quicker, and it can be stored for a much longer period.
Traditionally, coronary heart disease and high blood pressure were rare, but the prevalence is now increasing rapidly. Stroke is common. Diabetes was rare but is increasing gradually.
Mainland China
China is a diverse country, and the food culture varies by region.
Snapper (1965)… quoted an analysis by Guy and Yeh of Peiping (Peking) diets in 1938. There was a whole cereal/legume/vegetable diet for poorer people and a milled-cereal/meat/vegetable diet for the richer people.
Symptoms of vitamin A, C and D deficiency were common in the poor, although coronary heart disease and high blood pressure were rare. Diabetes occurred at a higher rate than in most traditionally-living populations.
Japan
On the Japanese island of Okinawa, the traditional staple is the sweet potato, with a smaller amount of rice eaten as well. Seafood, vegetables, pork and soy are also on the menu. In Akira Kurosawa’s movie Seven Samurai, set in 16th century mainland Japan, peasants ate home-processed millet and barley, while the wealthy ate white rice. Although a movie may not be the best source of information, I assume it has some basis in fact.
White Rice: a Traditional Asian Staple?
It depends on your perspective. How far back do you have to go before you can call a food traditional? Many peoples' grandparents ate white rice, but I doubt their great great grandparents ate it frequently. White rice may have been a staple for the wealthy for hundreds of years in some places. But for most of Asia, in the last few thousand years, it was probably a rare treat. The diet most likely resembled that of many non-industrial Africans: an assortment of traditionally prepared grains, root vegetables, legumes, vegetables and a little meat.
Please add any additional information you may have about traditional Asian diets to the comments section.
Nitrate: a Protective Factor in Leafy Greens
Cancer Link and Food Sources
Nitrate (NO3) is a molecule that has received a lot of bad press over the years. It is thought to promote digestive cancers, in part due to its ability to form carcinogens when used as a preservative for processed meat. Because of this (1), nitrate was viewed with suspicion and a number of countries imposed strict limits on its use as a food additive.
But what if I told you that by far the greatest source of nitrate in the modern diet isn't processed meat-- but vegetables, particularly leafy greens (2)? And that the evidence linking exposure to nitrate itself has largely failed to materialize? For example, one study found no difference in the incidence of gastric cancer between nitrate fertilizer plant workers and the general population (3). Most other studies in animals and humans have not supported the hypothesis that nitrate itself is carcinogenic (4, 5, 6), but rather that they are only carcinogenic in the context of processed meats due to the formation of carcinogenic nitrosamines. This, combined with recent findings on nitrate biology, has changed the way we think about this molecule in recent years.
A New Example of Human Symbiosis
In 2003, Dr. K. Cosby and colleagues showed that nitrite (NO2; not the same as nitrate) dilates blood vessels in humans when infused into the blood (7). Investigators subsequently uncovered an amazing new example of human-bacteria symbiosis: dietary nitrate (NO3) is absorbed from the gut into the bloodstream and picked up by the salivary glands. It's then secreted into saliva, where oral bacteria use it as an energy source, converting it to nitrite (NO2). After swallowing, the nitrite is reabsorbed into the bloodstream (8). Humans and oral bacteria may have co-evolved to take advantage of this process. Antibacterial mouthwash prevents it.
Nitrate Protects the Cardiovascular System
In 2008, Dr. Andrew J. Webb and colleagues showed that nitrate in the form of 1/2 liter of beet juice (equivalent in volume to about 1.5 soda cans) substantially lowers blood pressure in healthy volunteers for over 24 hours. It also preserved blood vessel performance after brief oxygen deprivation, and reduced the tendency of the blood to clot (9). These are all changes that one would expect to protect against cardiovascular disease. Another group showed that in monkeys, the ability of nitrite to lower blood pressure did not diminish after two weeks, showing that the animals did not develop a tolerance to it on this timescale (10).
Subsequent studies showed that dietary nitrite reduces blood vessel dysfunction and inflammation (CRP) in cholesterol-fed mice (11). Low doses of nitrite also dramatically reduce tissue death in the hearts of mice exposed to conditions mimicking a heart attack, as well as protecting other tissues against oxygen deprivation damage (12). The doses used in this study were the equivalent of a human eating a large serving (100 g; roughly 1/4 lb) of lettuce or spinach.
Mechanism
Nitrite is thought to protect the cardiovascular system by serving as a precursor for nitric oxide (NO), one of the most potent anti-inflammatory and blood vessel-dilating compounds in the body (13). A decrease in blood vessel nitric oxide is probably one of the mechanisms of diet-induced atherosclerosis and increased clotting tendency, and it is likely an early consequence of eating a poor diet (14).
The Long View
Leafy greens were one of the "protective foods" emphasized by the nutrition giant Sir Edward Mellanby (15), along with eggs and high-quality full-fat dairy. There are many reasons to believe greens are an excellent contribution to the human diet, and what researchers have recently learned about nitrate biology certainly reinforces that notion. Leafy greens may be particularly useful for the prevention and reversal of cardiovascular disease, but are likely to have positive effects on other organ systems both in health and disease. It's ironic that a molecule suspected to be the harmful factor in processed meats is turning out to be one of the major protective factors in vegetables.
Nitrate (NO3) is a molecule that has received a lot of bad press over the years. It is thought to promote digestive cancers, in part due to its ability to form carcinogens when used as a preservative for processed meat. Because of this (1), nitrate was viewed with suspicion and a number of countries imposed strict limits on its use as a food additive.
But what if I told you that by far the greatest source of nitrate in the modern diet isn't processed meat-- but vegetables, particularly leafy greens (2)? And that the evidence linking exposure to nitrate itself has largely failed to materialize? For example, one study found no difference in the incidence of gastric cancer between nitrate fertilizer plant workers and the general population (3). Most other studies in animals and humans have not supported the hypothesis that nitrate itself is carcinogenic (4, 5, 6), but rather that they are only carcinogenic in the context of processed meats due to the formation of carcinogenic nitrosamines. This, combined with recent findings on nitrate biology, has changed the way we think about this molecule in recent years.
A New Example of Human Symbiosis
In 2003, Dr. K. Cosby and colleagues showed that nitrite (NO2; not the same as nitrate) dilates blood vessels in humans when infused into the blood (7). Investigators subsequently uncovered an amazing new example of human-bacteria symbiosis: dietary nitrate (NO3) is absorbed from the gut into the bloodstream and picked up by the salivary glands. It's then secreted into saliva, where oral bacteria use it as an energy source, converting it to nitrite (NO2). After swallowing, the nitrite is reabsorbed into the bloodstream (8). Humans and oral bacteria may have co-evolved to take advantage of this process. Antibacterial mouthwash prevents it.
Nitrate Protects the Cardiovascular System
In 2008, Dr. Andrew J. Webb and colleagues showed that nitrate in the form of 1/2 liter of beet juice (equivalent in volume to about 1.5 soda cans) substantially lowers blood pressure in healthy volunteers for over 24 hours. It also preserved blood vessel performance after brief oxygen deprivation, and reduced the tendency of the blood to clot (9). These are all changes that one would expect to protect against cardiovascular disease. Another group showed that in monkeys, the ability of nitrite to lower blood pressure did not diminish after two weeks, showing that the animals did not develop a tolerance to it on this timescale (10).
Subsequent studies showed that dietary nitrite reduces blood vessel dysfunction and inflammation (CRP) in cholesterol-fed mice (11). Low doses of nitrite also dramatically reduce tissue death in the hearts of mice exposed to conditions mimicking a heart attack, as well as protecting other tissues against oxygen deprivation damage (12). The doses used in this study were the equivalent of a human eating a large serving (100 g; roughly 1/4 lb) of lettuce or spinach.
Mechanism
Nitrite is thought to protect the cardiovascular system by serving as a precursor for nitric oxide (NO), one of the most potent anti-inflammatory and blood vessel-dilating compounds in the body (13). A decrease in blood vessel nitric oxide is probably one of the mechanisms of diet-induced atherosclerosis and increased clotting tendency, and it is likely an early consequence of eating a poor diet (14).
The Long View
Leafy greens were one of the "protective foods" emphasized by the nutrition giant Sir Edward Mellanby (15), along with eggs and high-quality full-fat dairy. There are many reasons to believe greens are an excellent contribution to the human diet, and what researchers have recently learned about nitrate biology certainly reinforces that notion. Leafy greens may be particularly useful for the prevention and reversal of cardiovascular disease, but are likely to have positive effects on other organ systems both in health and disease. It's ironic that a molecule suspected to be the harmful factor in processed meats is turning out to be one of the major protective factors in vegetables.
Brushing your teeth may prevent disease
A new study from the BMJ revealed that people who never or only rarely brush their teeth twice a day are up to 70% more likely to develop heart disease.
Although scientists have long suspected a relationship between gum disease and heart problems, this is the first study to high the dangers of poor oral hygiene.
Experts are unsure of the exact reason for the link, but suggest that it may be a result of inflammation in the mouth and gums, which they believe is connected to the build up of clogged arteries.
However despite the findings, the researchers stressed that the overall risk of heart disease from oral hygiene remains relatively low.
In the survey of more than 11,000 people, just 71% said they brushed their teeth twice a day and only 62% said they visited the dentist every six months.
Fermented Grain Recipes from Around the World
In my last two posts on grains, I described how traditional food processing methods make grains more nutritious and digestible (1, 2). I promised to briefly describe a few recipes from around the world, then got distracted by other things. Here they are.
Africa: Ogi
Grain fermentation is widespread in Africa and is probably nearly as old as agriculture on the continent. The nutritional importance of fermentation is suggested by the amount of time and effort that many African cultures put into it, when they could save themselves a lot of trouble by simply soaking and cooking their grains.
Ogi is a common West African porridge that's eaten as a staple food by people of all ages. It's even used as a weaning food. It's made in essentially the same manner from corn, sorghum or millet.
Whole grain is soaked in water for one to three days. It's then wet milled, mixed with water and sieved to remove a portion of the bran. Extra bran is fed to animals, while the white, starchy sediment is fermented for two to three days. This is then cooked into a thin or thick porridge and eaten.
South America: Pozol
At first glance, some people may think I left the 'e' off the word 'pozole', a traditional Mexican stew. However, pozol is an entirely different beast, an ancient food almost totally unknown in the US, but which fueled the Mayan empire and remains a staple food in Southeastern Mexico.
To make pozol, first the corn must be 'nixtamalized': whole kernels are boiled in a large volume of water with calcium hydroxide (10% w/v). This is a processing step in most traditional South American corn recipes, as it allows a person to avoid pellagra (niacin deficiency)! The loosened bran is removed from the kernels by hand.
The kernels are then ground into dough, formed into balls and placed into banana leaves to ferment for one to 14 days. Following fermentation, pozol is diluted in water and consumed raw.
Europe: Sourdough Bread
Sourdough bread is Europe's quintessential fermented grain food. Before purified yeast strains came into widespread use in the 20th century, all bread would have been some form of sourdough.
Although in my opinion wheat is problematic for many people, sourdough fermentation renders it more nutritious and better tolerated by those with gluten/wheat sensitivity. In an interesting series of studies, Dr. Marco Gobbetti's group, among others, has shown that fermentation partially degrades gluten, explaining the ability of fermentation to decrease the adverse effects of gluten in those who are sensitive to it (3). They even showed that people with celiac disease can safely eat wheat bread that has been long-fermented with selected bacteria and yeasts under laboratory conditions (4). Rye contains about half the gluten of bread wheat, and is generally nutritionally superior to wheat, so sourdough rye is a better choice in my opinion.
To make sourdough bread, first the dry grains are ground into flour. Next, the flour is sifted through a screen to remove a portion of the bran. The earliest bread eaters probably didn't do this, although there is evidence of the wealthy eating sifted flour in societies as old as ancient Egypt and ancient Rome. I don't know what the optimum amount of bran to include in flour is, but it's not zero. I would be inclined to keep at least half of it, recognizing that the bran is disproportionately rich in nutrients.
Next, a portion of flour is mixed with water and a "sourdough starter", until it has a runny consistency. The starter is a diverse culture of bacteria and yeast that is carefully maintained by the bread maker. This culture acidifies the batter and produces carbon dioxide gas. The mixture is allowed to ferment for 8-12 hours. Finally, flour and salt are added to the batter and formed into dough balls. These are allowed to ferment and rise for a few hours, then baked.
My Experience
I've tried making ogi (millet) and pozol, and I have to admit that neither attempt was successful. Pozol in particular may depend on local populations of bacteria and yeast, as the grains' microorganisms are killed during processing. However, I do eat fermented grains regularly in the form of homemade brown rice 'uthappam' and sourdough buckwheat 'crepes'. The buckwheat crepes are tasty and easy to make. I'll post a recipe at some point.
The first two recipes are from the FAO publication Fermented Cereals: a Global Perspective (5).
Africa: Ogi
Grain fermentation is widespread in Africa and is probably nearly as old as agriculture on the continent. The nutritional importance of fermentation is suggested by the amount of time and effort that many African cultures put into it, when they could save themselves a lot of trouble by simply soaking and cooking their grains.
Ogi is a common West African porridge that's eaten as a staple food by people of all ages. It's even used as a weaning food. It's made in essentially the same manner from corn, sorghum or millet.
Whole grain is soaked in water for one to three days. It's then wet milled, mixed with water and sieved to remove a portion of the bran. Extra bran is fed to animals, while the white, starchy sediment is fermented for two to three days. This is then cooked into a thin or thick porridge and eaten.
South America: Pozol
At first glance, some people may think I left the 'e' off the word 'pozole', a traditional Mexican stew. However, pozol is an entirely different beast, an ancient food almost totally unknown in the US, but which fueled the Mayan empire and remains a staple food in Southeastern Mexico.
To make pozol, first the corn must be 'nixtamalized': whole kernels are boiled in a large volume of water with calcium hydroxide (10% w/v). This is a processing step in most traditional South American corn recipes, as it allows a person to avoid pellagra (niacin deficiency)! The loosened bran is removed from the kernels by hand.
The kernels are then ground into dough, formed into balls and placed into banana leaves to ferment for one to 14 days. Following fermentation, pozol is diluted in water and consumed raw.
Europe: Sourdough Bread
Sourdough bread is Europe's quintessential fermented grain food. Before purified yeast strains came into widespread use in the 20th century, all bread would have been some form of sourdough.
Although in my opinion wheat is problematic for many people, sourdough fermentation renders it more nutritious and better tolerated by those with gluten/wheat sensitivity. In an interesting series of studies, Dr. Marco Gobbetti's group, among others, has shown that fermentation partially degrades gluten, explaining the ability of fermentation to decrease the adverse effects of gluten in those who are sensitive to it (3). They even showed that people with celiac disease can safely eat wheat bread that has been long-fermented with selected bacteria and yeasts under laboratory conditions (4). Rye contains about half the gluten of bread wheat, and is generally nutritionally superior to wheat, so sourdough rye is a better choice in my opinion.
To make sourdough bread, first the dry grains are ground into flour. Next, the flour is sifted through a screen to remove a portion of the bran. The earliest bread eaters probably didn't do this, although there is evidence of the wealthy eating sifted flour in societies as old as ancient Egypt and ancient Rome. I don't know what the optimum amount of bran to include in flour is, but it's not zero. I would be inclined to keep at least half of it, recognizing that the bran is disproportionately rich in nutrients.
Next, a portion of flour is mixed with water and a "sourdough starter", until it has a runny consistency. The starter is a diverse culture of bacteria and yeast that is carefully maintained by the bread maker. This culture acidifies the batter and produces carbon dioxide gas. The mixture is allowed to ferment for 8-12 hours. Finally, flour and salt are added to the batter and formed into dough balls. These are allowed to ferment and rise for a few hours, then baked.
My Experience
I've tried making ogi (millet) and pozol, and I have to admit that neither attempt was successful. Pozol in particular may depend on local populations of bacteria and yeast, as the grains' microorganisms are killed during processing. However, I do eat fermented grains regularly in the form of homemade brown rice 'uthappam' and sourdough buckwheat 'crepes'. The buckwheat crepes are tasty and easy to make. I'll post a recipe at some point.
The first two recipes are from the FAO publication Fermented Cereals: a Global Perspective (5).
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