Diets modern

Scurvy results from a dietary vitamin C deficiency and involves the inability to form collagen fibrils properly. This is the result of reduced activity of prolyl hydroxylase, which is vitamin C-dependent, as previously noted. Scurvy leads to lesions in the skin and blood vessels, and, in its advanced stages, it can lead to grotesque disfiguration and eventual death. Although rare in the modern world, it was a disease well known to sea-faring explorers in earlier times who did not appreciate the importance of fresh fruits and vegetables in the diet. 

With modern production methods 1500 kilograms of petroleum per hectare are needed for rice and 700 kilograms for maize. However, with this commercial energy use, yields of 5.8 metric tons per hectare have been obtained for rice and 5 metric tons per hectare for maize—about five times those obtained with traditional methods. Thus, 20 to 25 people can be fed on an all-grain diet from a single hectare compared with 4 to 6 people by traditional methods. 

Where CO2 in the free atmosphere has a 5 C value of-7%o, C3 and C4 plants are anticipated to have 5 C values of about -26.5%o and -12.5%o respectively (van der Merwe 1989) archaeological maize, however, typically averages -9.5%o(Schwarcz et al. 1985). The isotopic values of modern maize and C3 plant foods in Mesoamerica (Wright 1994 203-206), after correction for the Industrial Effect, average -9.6%o and -26.4%o respectively. Since herbivore collagen is typically enriched by +5%o relative to the diet (van der Merwe 1989), animals from this region with a pure C3 plant diet should... 

Table 2.2. Carbon isolope values in collagen of modern and ancicni fauna wiih C3 plant diets. The isotope values for ancient armadillo were not included in the average since they dearly consumed some C4 plants.

More is known about nitrogen. In a study of modern humans where diet components (protein, lipid and carbohydrate) were measured against the corresponding body components, a shift of between 4.2 and 4.4%o was observed for nitrogen in both plasma protein and hair (Schoeller et al. 1986). This is just outside the usual 3-4%o range. Salmon fishers from coastal British Columbia are enriched by 3%o compared to their diet (Chisholm et al. 1983). Ancient Mexicans have constant 8 N values, as reported by DeNiro and Epstein (1981) 8-10%o, and While and Schwarcz (1989) 9.8 0.8%o. In the latter... 

Schoeninger, M.J. 1982 Diet and evolution of modern human form in the Middle East. American Journal of Physical Anthropology 58 37-52. 

Table 12.1. Diec-lissue differences iri 5 N CA N) in controlled diet experiments and within modern natural ecosystems.

Carnivores rely on a protein-rich diet and produce new biomass primarily from dietary amino acids, although the enzymes required for de novo amino acid synthesis are present (Garmes et al., 1998). Bone collagen, muscle (meat) and apatite were analyzed for a set of modern southern African herbivores and carnivores (Lee-Thorp et al., 1989). The isotopic analyses showed i C enrichment in bone collagen, apatite and muscle, and depletion in lipids. Difference in values between herbivores and carnivores indicates a trophic effect, which for carbon in bone collagen is 2.5-3%o (Fig. 2). 

It might be expected that EN via tubes would have been used widely before the development of parenteral nutrition (PN) however, this was not actually the case. EN via tubes inserted down the mouth or nose into the stomach and also via rectal tubes was used occasionally in the decades before the development of PN in the 1960s.1 However, modern techniques for enteral access, both the placement of the tubes themselves and the materials for making pliable, comfortable tubes, had not yet been developed. Before the PN era, the formulas delivered by the tube route often were blenderized foods. The National Aeronautics and Space Administration effort in the United States in the 1960s led to the development of low-residue (monomeric) diets for astronauts. These diets were adapted for use in sick patients requiring EN. Nonvolitional feedings in patients who cannot meet nutritional requirements by oral intake thus include EN and PN these techniques are collectively known as specialized nutrition support (SNS). 

The exact contribution of modern pharmaceuticals to our increased longevity can be only estimated and weighed in comparison with improved diet and life-... 

As has been pointed out earlier in this chapter, the dietary consumption and historical medicinal use of carotenoids has been well documented. In the modern age, in addition to crocin, 3.7, and norbixin, 3.8, several carotenoids have become extremely important commercially. These include, in particular, astaxanthin, 3.6 (fish, swine, and poultry feed, and recently human nutritional supplements) lutein, 3.4, and zeaxanthin, 3.3 (animal feed and poultry egg production, human nutritional supplements) and lycopene, 3.2 (human nutritional supplements). The inherent lipophilicity of these compounds has limited their potential applications as hydrophilic additives without significant formulation efforts in the diet, the lipid content of the meal increases the absorption of these nutrients, however, parenteral administration to potentially effective therapeutic levels requires separate formulation that is sometimes ineffective or toxic (Lockwood et al. 2003). 

Figure 8.10 Carbon isotope ratios in bone collagen plotted against radiocarbon ages for 183 British Mesolithic and Neolithic humans from coastal (within 10 km of modern coastline squares) and inland sites (crosses). The sharp change in carbon isotope ratio at around 5200 radiocarbon years BP is interpreted as a shift from a marine diet to one dominated by terrestrial protein. This coincides with the onset of the Neolithic period in Britain. (Reproduced from Richards et al. 2003, with permission of Nature Publishing Group and the first author.)...

Early twentieth century alarm over the presumed pathological effects of uric acid provoked considerable concern among both physicians and the public for controlling "uricacidemia" through diet and medication. Although finally discarded as merely a fetish, the uric acid scare is an impressive illustration of the impact of modern chemistry on popular, as well as medical thought. 

There can be no objection to the ingestion of bulk substances for the purpose of supplementing low-residue modern diets. However, use of irritant purgatives or cathartics is not without hazards. Specifically, there is a risk of laxative dependence, i.e the inability to do without them. Chronic intake of irritant purgatives disrupts the water and electrolyte balance of the body and can thus cause symptoms of illness (e.g., cardiac arrhythmias secondary to hypokalemia). 

Elements are incorporated into teeth from the diet or by inhalation. The figure shows trace element profiles measured by laser ablation—plasma ionization-mass spectrometry of the dentine of teeth from a modem person and one who lived in Scandinavia about a.d. 1800. The contrast is striking. The old tooth contains significant amounts of tin and bismuth, which are nearly absent in the modern tooth. The old tooth contains more lead and antimony than the modem tooth. Tin and lead are constituents of pewter, which was used for cooking vessels and utensils. Bismuth and antimony also might come from pewter. 

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