Students would do well to consider the role of magnesium from plant sources as a particularly illuminating case study. Magnesium is recognized to have a central role in human well being, affecting cardiovascular, neurological, and immunological health. It is synergistic with the fat soluble vitamins A and D, and so its deficiency is likely to affect health in a similar way to their restriction, potentially even in regard to maintaining robust immunity.Magnesium is vital during pregnancy: research shows that the mineral reduces the risk of complications such as preeclampsia and preterm birth.Through its synergistic role with vitamin D, moreover, magnesium is known to affect skeletal health. Recent research thus shows a strong link between magnesium deficiency and osteoporosis. Due to their profound role in skeletal health, we could also hypothesize that deficiency of magnesium and fat soluble vitamins may affect the growth and vitality of children. Children without sufficient vitamin D, for example, may develop serious disorders such as rickets. Females may suffer from poor pelvic development, which can have serious implications for childbearing. A reduction in magnesium consumed from plant sources, which is synergistic with vitamin D, would therefore have problematic implications.Having examined the often-overlooked importance of dietary magnesium,stackable flower pots students would assess whether and how its intake decreased in many Native American diets following colonization.

Magnesium, after all, is present at high levels in sunflower, pumpkin and squash seeds, beans, and green vegetables – all foods that were consumed readily in many communities before colonization, but which became less accessible as more land was cultivated by Europeans. Indigenous communities moved from point of contact towards the Great Plains and elsewhere, losing traditional horticultural and/or plant-gathering patterns. And so, diminished access to magnesium would have been likely to exacerbate the decline in health and fertility following the biological exchange of infectious diseases after contact. In addition to their magnesium case study, it would be fruitful for students to consider the vital importance of plant sources of folate and the problems potentially associated with its curtailment as a nutritional source in Native American communities. When fertility and demography were already ravaged by infectious diseases, the ability to recover population numbers through reproduction may have been threatened by a reduction in folate among women of a child-bearing age. In addition to minerals such as magnesium, zinc, and iron, folate is known to be important for fetal development and maternal health during pregnancy.One study highlights the importance of folate in oocyte maturation: subjects receiving IVF treatment who also received folate were found to have more mature eggs than those who did not receive folate.Folate deficiency is a well-known cause of neural tube defects, and low maternal folate levels may increase risk of spontaneous abortion . Lack of folate during pregnancy is correlated with other complications including low birth weight, placental abruption, fetal growth retardation, and preeclampsia. Some studies have highlighted the importance of folate in male fertility. For example, a double-blind randomized placebo-controlled trial found a 74% increase in total normal sperm count in sub-fertile men who received both zinc sulfate and folic acid daily for 26 weeks, while another study found an association between folate consumption and sperm aneuploidy.Thus, a decrease in the consumption of beans, squash, and other fresh vegetables at the expense of less folate-rich calorie sources could be expected to have had a large impact on the health of the population through effects on fertility, maternal health during pregnancy, and child development .

The importance of folate can be further illustrated by research among those who suffer from genetic mutations such as MTHFR C677T, which is prevalent among many different human populations, and which has been associated with effects on health such as increased rates of miscarriage. A properly working MTHFR enzyme normally transfers 5,10- methylenetetrahydrofolate into an activated form, 5-MTHF . Such a process is crucial for DNA methylation, nucleic acid biosynthesis, neurotransmitter synthesis, and the creation of signaling molecules that are central to the development of embryos in the first trimester of pregnancy. Folate plays a vital role in remethylation of homocysteine to methionine, which is essential for DNA-synthesis, DNA-repair, and DNA-imprinting processes.If these processes are reduced through mutations in methylation pathways, levels of intercellular folate become insufficient, making its ready consumption potentially more vital. Having familiarized themselves with the role of such enzymatic activity, including the role of folate in facilitating bodily detoxification through methylation pathways, students would be able to examine the following hypothesis: reduced folate intake from plants would have diminished the ability of post-contact Native Americans – particularly women of childbearing age – to respond through reproduction to demographic pressures caused by disease. Having considered these case studies, students would also be encouraged to assess the interaction between plant nutrition and animal products. Many of the fatty acids and nutrients detailed in the previous section of this article can be found in wild animal sources .But as we have seen in this section, plant sources were often important on their own terms, irrespective of their combination with animal fats. Still, students might consider recent research that has shown the extent to which some vitamins found in plants are better absorbed by humans in the presence of fats, most likely from animal sources.

They would do well to assess recent scientific literature on the problematic bio-availability of some nutrients found in plants, including essential vitamins as well fat-soluble carotenoid compounds such as lutein, lycopene, beta-carotene and zeaxanthin. Indeed, some research has even prioritized saturated fat over polyunsaturated fats such as sunflower oil in facilitating the bio-availablity of beta-carotene in plant materials. As horticulture declined after contact, so therefore did the consumption of plant nutrients in combination with fats from animal sources, which may have increased their ability to be processed and absorbed in humans.Such a nutritional paradigm would support our scholarly and pedagogical attempt to reduce the dichotomy between indigenous hunting methods and pre-contact horticulture. It would also allow us to understand one of the nutritional roles of animal products in regions south of the Canadian Arctic, British Columbia, and the northern Great Lakes; where plants, some grains, tubers, chenopods, and seeds were consumed in greater proportion relative to animal products than among northern native populations. Where climate, season, and ecology permitted the consumption of calories from cultivated and/or gathered plants,tower garden their nutritional benefits might have been maximized through their combination with animal sources. The latter were gained from hunting practices that continued much later in Native American history than among Neolithic and post-Neolithic European populations. Thus the susceptibility of Native Americans to European diseases may have been further amplified by their disrupted access to certain meats and fishes, as well as a diminished opportunity to consume them in combination with cultivated plants; so as to decrease health, immunity, and fertility even prior to infection. Aside from the potential decline in vitamins and anti-oxidants from indigenously cultivated fruits and vegetables, and their potentially greater absorption in the presence of fat, it is also important for students to consider metabolic distinctions between previously cultivated plant sources and the grains that Native Americans came to rely upon more greatly following colonization; whether any correlation can be drawn between forced changes in starch consumption and declining health markers in post-contact Native America; and whether these changes in the metabolic nutritional profile of their food compromised Native American immunological health with respect to infectious diseases. Here students would be required to examine the potential distinction between micro-nutrient health effects and those associated with the metabolic effects of various macro-nutrient profiles, as defined by their relationship with energy utilization and storage in the human body. A central aspect of the metabolic profile of food is considered to be the resulting effect on blood sugar level and the concomitant production of insulin . [98] In order to consider the question of metabolic health, students might begin by examining a number of ethnobotanic assessments of Pima Indian ancestral food patterns, which provide a rich and useful case study. Alarmed by the sudden prevalence of diabetes among the Pima communities of southern Arizona since their adoption of an American diet during the 1940s Arizona ethnobotanist Gary Paul Nabhan has scrutinized ancestral Pima diets from anthropological sources, working on behalf of the Tucsonbased Native Seeds/SEARCH foundation. Nabhan and others have noted a contrast between the starches traditionally gathered and/or cultivated by the community during the last several hundred years, which promote a much lower insulin response, and more recently consumed grains, newer strains of maize, and white potatoes . Such a distinction was correlated by selecting six starchy foods traditionally eaten by the Pimas during the last millennium, and particularly prior to first European contact: mesquite pods, acorns, white and yellow tepary beans, lima beans and a traditional strain of corn.

The blood insulin levels following consumption of these foods was measured in healthy, non-diabetic subjects and compared to newer starch sources consumed by the same subjects. Some of the sources analysed have been shown to contain higher-thanaverage proportions of amylose starch, which takes longer to break down into simple sugars than amylopectin, the predominant starch found in white potatoes and bread, thereby explaining the lower rises in blood sugar after consumption of these starch sources.Prior to contact, Pima populations also consumed a cereal containing the grain-like seeds of psyllium, sometimes known as plantago, which more recent studies have linked to the potential lowering of fasting blood sugar levels. Another study has even suggested that the phytochemical composition and metabolic performance of some “dietary berries traditionally used by Native Americans” can be associated with positive health markers, including the regulation of blood sugar levels and lipid metabolism. “For Native American and other recently Westernized indigenous people,” according to Nabhan, “a return to a diet similar to their traditional one is no nostalgic notion; it may, in fact, be a nutritional and survival imperative.” From such an analysis, at least, students of Native American ancestral health might draw a related hypothesis: following Spanish and AngloAmerican colonization of the Southwest, reduced access to lower-glycemic starches in favor of maize and wheat could well have heightened the susceptibility of indigenous communities to infectious diseases and/or raised their mortality after infection. Several modern studies, after all, have suggested that the immune response might be impaired in individuals with diabetes mellitus, or even among those who have chronically raised fasting blood sugar levels. Aside from their greater reliance on less-nutritional and higher glycemic starches after colonization, Native Americans might also have suffered from reduced access to Resistant Starch – another hypothesis that should inspire students and researchers to consider the intersection between historical data and modern scientific debates in evolutionary health. As a beneficial substrate for fermentation, instead of being digested by amylases in the upper digestive tract, RS tends to pass through to the bowel, where it is fermented by bacteria into short chain fatty acids . It has been suggested that RS is important in contributing to a healthy gut biome.Interestingly, a good source of RS can be found in acorn powder.We know that Native American communities throughout North America ground up acorns and ate the powder with other foods. And as we have seen, many lamented diminished access to acorns as a result of post-contact European domesticated agriculture. Recent medical literature has shown that RS may reduce the potential for Type II diabetes in populations who eat carbohydrates. As is evident in the Pima studies, a decline in the consumption of mesquite pod and acorn powder, both good sources of RS, has been accompanied by an increase in diabetes. Thus, future students and scientific researchers might ask: did Native Americans inadvertently lose important forms of RS as their preparation and consumption of acorns and other seeds and tubers gave way to wheat and corn? Or put differently, did European colonization alter the Native-American gut-biome, and did this further contribute to the decline in overall health and immunity? Assessing the role of plant starch sources in Native America also raises the related question of their seasonality, and whether disruption of their consumption at certain times contributed to a decline in health, immunity, and even fertility. In New England through the 1600s, as Anderson has shown, European farming enclosures clashed with the summer gathering of tubers and squash, while tending animals in the winter conflicted with itinerant winter hunting for fats and proteins.