Saturday, October 08, 2005

** Some Like it Hot by Gary Nabhan

Some Like it Hot by Gary Nabhan

We are what our ancestors ate, and also what they had to regurgitate, for there are as many poisonous plants, fungi, fish, and shellfish surrounding us as there are edible. P4

The weaning of most breast fed children in the world may be precipitated by a gradual decline in the activity of lactase. P18

Around 10,000 years ago, a mutation occurred in the DNA of an isolated population of northern Europeans that allowed them to tolerate milk as a nutrient rich resource… Certain ethnic populations that carried this gene in low frequencies – and then subsequently adopted a pastoral lifestyle and cultured milk consumption – found that their lactase activity gradually extended into adulthood… This small percentage of lactose tolerant individuals was rapidly favored so that within just 15 generations the frequency of lactose tolerance increased dramatically. P19

The evidence suggests that people took up a pastoral way of life first, and developed milk digesting ability later in response to it… Human beings created their own evolutionary pressures (Matt Ridely, Genome 2000) p21

Agrarian populations may have reduced their exposure to dysentery by drinking fermented beverages made from grains, grapes, or potatoes, instead of drinking untreated water. Nomadic people had until recently little exposure to livestock fouled drinking water and hence little hygienic incentive to produce fermented beverages… (Ridely, Genome) p29

Key components of the ancestral diet p40
  1. Our hunter gatherer ancestors may have gained as much as 65% of their calories from vertebrate animals, while seldom eating eggs, and never consuming milk products.

  2. They consumed raw forms of fruits, flowers, leaves, and bulbs.

  3. They rarely ate cereals, certainly not fine ground, fiber depleted grains and seeds.

  4. Neither did they consume quantities of sodium.

  5. They did not consume fermented carbohydrates either as alcohol or vinegar

The very foods that our hominid ancestors ate millions of years ago are still what our metabolisms are best suited to consume… We ignore at our peril, the fact that human biology is designed for Stone Age conditions. P37

Archaeologists seem less certain that there is a single discernible dietary pattern evident among excavated sites. Some scholars have begun to doubt whether Java man ever kept to a uniform diet; some even wonder if ancestral diets contained more or less the same proportion of fats, proteins, sugars, and fiber. P50

Paleonutritionists insist that if you averaged it out over 100,000s of years, the animal to plant ratio of energy intake would be 2/3 meat to 1/3 veggies. [However Loren Cordain, author of Paleo Diet – coming soon to this blog – states] ‘our data clearly indicate that there was no single diet that represented all hunter-gatherer societies.’ P55

It is probable that there was far more genetic differentiation between the populations of our ancestors than there is today. If genetic studies of chimpanzee populations are any indication, there was also greater variability within each breeding population. The chimps within one breeding population on a hillside in Africa express twice as much variability in their mitochondrial DNA than do all of the 6 billion humans currently living around the Earth. P60

If you eat too many fava beans, your GSH levels plummet just as they do when you are given an antimalarial drug. The diminished GSH levels interfere with the growth and replication of malarial parasites, thereby offering any fava bean eater temporary resistance to this infectious disease, but the resistance is clearly enhanced in carriers of a G6PD deficiency allele [which is common in Mediterranean populations. Sardinia having the highest concentration known]. P87

Could the secret of the touted ‘Mediterranean diet’ discovered on Crete be partly due to caloric restriction? There is something deeply cultural about the way Cretans eat – and about what they don’t eat… 60 of 120 that were tracked [50%] strictly observe religious fasts that occur over 180 days each year… Most forego meat, dairy and eggs, while others forego olive oil as well. Snails, calamari, and other invertebrates are acceptable. There are days when one must eat or not eat fish. What are the effects on the health of the fasters? It’s significant – about a 12% reduction in their serum lipoproteins – the amount of fat in their blood. P106

Neither birds, reptiles, nor amphibians have much capacity to chemically sense capsaicin as a source of ‘heat’. Only mammals have the innate ‘sense’ to avoid chiles, and this sensitivity appears to have developed rather recently in their evolution. [How did it happen? Chile seeds to be deposited under trees for shade under the desert sun. Mammals, namely mice and other rodents, are not reliable at dispersing chile seeds accordingly. Worse, they masticate the seeds on many occasions. Birds however, perch on tree branches, and defecate often while perching, allowing the seeds to fall to the base of the tree, where it can germinate and be shaded. How to entice the birds? Birds need carotene in red and orange for their bright plumage? How to discourage the mammals? Capsaicin.]

Why do humans eat capsaicin? Areas closer to the equator would suffer higher ambient temperatures and more rapid meat spoilage… Antimicrobial defenses against meat spoilage were the driving forces behind eating spices, the same ethnic cuisine would contain more spicy meat dishes than vegetable dishes. In addition, the percentage of meat dishes containing spices would increase the nearer the culture lived to the equator. P134

The farther north you live, the tougher it is to get [your] greens – the Inuit must obtain them from the lichen ‘stomach salads’ removed from Caribou intestines [yummy]. P159

Hunter gatherers were likely to exhibit a thrifty genotype that was a vestigial survival mechanism from eras during which they suffered from irregular food availability. ‘During the first 99% or more of man’s life on earth while he existed as a hunter-gatherer, it was often feast or famine. Periods of gorging, alternated with periods of greatly reduced food intake.’ James Neel, 1962 p176

However, this ‘thrifty genotype’ hypothesis has been challenged. Jennie Brand Miller hammered the coffin closed on the ‘thrifty genotype’ hypothesis by refuting its very underpinnings – that famines were more frequent among hunter-gatherers than among agriculturists, leading to the former’s extraordinary capacity to accumulate fat reserves. She found scant evidence that hunter-gatherers suffered from these stresses anywhere near as frequently as the agriculturists did. In fact, periodic starvation and widespread famines increased in frequency less than 10,000 years ago, after various ethnic groups became fully dependent on agricultural yields. Caucasians have repeatedly suffered from famines in historic times, they ought to be predisposed to insulin resistance and diabetes in the ‘thrifty genotype’ is correct. And yet, Caucasians are one of the few groups that do not exhibit much insulin resistance when they consume modern agricultural diet. P178

Why would Caucasians not be predisposed to insulin resistance? 1st, when an ethnic population shifts to an agricultural diet and abandons a diverse cornucopia of wild foods, its members lose many secondary plant compounds that formerly protected them from impaired glucose tolerance. 2nd, when remaining beneficial compounds in traditional crops and livestock are selected out of a people’s diet through breeding, their diet is further depleted of protective factors. [Livestock raised on cereal grains lack omega 3, while their wild counterparts have this fatty acid.] 3rd, the industrial revolution changed the quality of carbohydrates by milling away most of the fiber. 4th, the last 50 years has introduced additives such as trans fat, syrups, fiber depleted starches, which raises blood sugar 3 times higher than humans ever experienced during pre-agricultural periods in our evolution. Although nearly all ethnic populations have come to suffer from foods over the past 25 years, the other changes took place in European societies over 1000s of years. The genetic constituency of European peoples may have slowly shifted with these technological and agricultural changes as they emerged. P180

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