cooking
Proc Natl Acad Sci U S A. 2011 Nov 29;108(48):19199-203. doi: 10.1073/pnas.1112128108. Epub 2011 Nov 7.
Energetic consequences of thermal and nonthermal food processing.
Carmody RN1, Weintraub GS, Wrangham RW.
Abstract
Processing food extensively by thermal and nonthermal techniques is a unique and universal human practice. Food processing increases palatability and edibility and has been argued to increase energy gain. Although energy gain is a well-known effect from cooking starch-rich foods, the idea that cooking meat increases energy gain has never been tested. Moreover, the relative energetic advantages of cooking and nonthermal processing have not been assessed, whether for meat or starch-rich foods. Here, we describe a system for characterizing the energetic effects of cooking and nonthermal food processing. Using mice as a model, we show that cooking substantially increases the energy gained from meat, leading to elevations in body mass that are not attributable to differences in food intake or activity levels. The positive energetic effects of cooking were found to be superior to the effects of pounding in both meat and starch-rich tubers, a conclusion further supported by food preferences in fasted animals. Our results indicate significant contributions fromcooking to both modern and ancestral human energy budgets. They also illuminate a weakness in current food labeling practices, which systematically overestimate the caloric potential of poorly processed foods.
Comment in
Cooking clue to human dietary diversity. [Proc Natl Acad Sci U S A. 2011]
A calorie is not necessarily a calorie: technical choice, nutrient bioaccessibility, and interspecies differences of edible plants. [Proc Natl Acad Sci U S A. 2012]
PMID: 22065771 [PubMed - indexed for MEDLINE] PMCID: PMC3228431 Free PMC Article
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Proc Natl Acad Sci U S A. 2011 Aug 30;108(35):14555-9. doi: 10.1073/pnas.1107806108. Epub 2011 Aug 22.
Phylogenetic rate shifts in feeding time during the evolution of Homo.
Organ C1, Nunn CL, Machanda Z, Wrangham RW.
Abstract
Unique among animals, humans eat a diet rich in cooked and nonthermally processed food. The ancestors of modern humans who invented food processing (including cooking) gained critical advantages in survival and fitness through increased caloric intake. However, the time and manner in which food processing became biologically significant are uncertain. Here, we assess the inferred evolutionary consequences of food processing in the human lineage by applying a Bayesian phylogenetic outlier test to a comparative dataset of feeding time in humans and nonhuman primates. We find that modern humans spend an order of magnitude less time feeding than predicted by phylogeny and body mass (4.7% vs. predicted 48% of daily activity). This result suggests that a substantial evolutionary rate change in feeding time occurred along the human branch after the human-chimpanzee split. Along this same branch, Homo erectus shows a marked reduction in molar size that is followed by a gradual, although erratic, decline in H. sapiens. We show that reduction in molar size in early Homo (H. habilis and H. rudolfensis) is explicable by phylogeny and body size alone. By contrast, the change in molar size to H. erectus, H. neanderthalensis, and H. sapiens cannot be explained by the rate of craniodental and body size evolution. Together, our results indicate that the behaviorally driven adaptations of food processing (reduced feeding time and molar size) originated after the evolution of Homo but before or concurrent with the evolution of H. erectus, which was around 1.9 Mya.
PMID: 21873223 [PubMed - indexed for MEDLINE] PMCID: PMC3167533 Free PMC Article
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日経サイエンスで食欲の特集があり、その関係で、リチャード・ランガム「火の賜物 人は料理で進化した」を取り寄せて読んだ。
There was a special issue of appetite of Japanese edition of Scientific American. I was impressed by the article of Richard Wrangham. Therefore, I am reading his book, entitled "Catching Fire --- How cooking made us human".
基本的に進化論についての料理仮説を詳しく説明した本である。趣旨は、人類は火を使って料理したので、消化器官の負担が減り、脳が大きくできたという。科学的根拠もある程度研究されている。つまり、ある程度は合理性のある仮説だろう。
It is the book which explained the cooking hypothesis about the theory of evolution in detail. Very briefly, the burden of the digestive organs decreased, and the our brain able to became large, since human beings cooked the food using fire. The scientific basis was also studied to some extent. That is, probably, this hypothesis may be true for some extent.
炭水化物を調理した場合の消化率は95%、調理しない場合の消化率はその半分くらい。タンパク質を調理した場合の消化率は91～94%、調理しない場合は51～65%。フリーズドライを多用すれば多少は吸収率が良くなるが、ジップロッククッキングでもお湯を使った方がよいと思う。
The digestive rate of carbohydrate was : when cooked 95%, when no-cooked 48-71%. The digestive rate of protein: when cooked 91-94%, when no-cooked 51-65%. When freeze dry food is used abundantly, the digestive rate will be improved. But, I recommend the use of hot water, even when we cook food using zip lock pack.
注目すべき記述をピックアップしておこう。
ケプニックらによる食物の70～100%を生で食べる513名の生食主義者の調査。--- 生で食べる食物の割合が増えるほど、BMIが下がる。料理した食物から生の食事に移行した時の平均的な体重の減少は、女性が26.5ポンド(12kg)、男性が21.8ポンド(9.9kg)。純粋な生食主義者の集団(全体の31%)のうち、3分の1が慢性的なエネルギー欠乏を示す体重だった。」(p.20) ... 「完全な生食の女性の50%が無月経となった。さらに約10%の月経が不規則になり、妊娠が見込めなくなった」(p.22)
炭水化物の消化率(p.31) ---カラスムギ、小麦、ジャガイモ、料理用バナナ、通常のバナナ、コーンフレーク、白パン、そしてヨーロッパまたはアメリカの典型的な食事(澱粉質の食物、乳製品、肉の混合)については、加熱された澱粉の少なくとも95%が小腸終端部までに消化吸収される。同じ計測で、加熱していない澱粉の小腸での消化率はかるかに低い。小麦の澱粉は71%、ジャガイモは51%、バナナ類の生の澱粉はわずか48%である。 ．．．実験でもやはり生の澱粉が消化されにくいことが確かめられた。しばしばその消化率は、熱を加えた澱粉の半分になる。
タンパク質の消化率(p.66-67)---料理した卵の場合には、タンパク質の消化率は平均91～94%だった。．．．しかし、回腸造瘻術の患者について、生の卵の消化率を測定すると、わずか51%しかなかった。呼気内の安定同位元素の含有率から推測した、健康な志願者の消化率は65%で、いくらか高かった。．．．料理はの卵のタンパク質の価値を40%高めていた。
後半は大した内容ではなかったな。料理の必要性についての民俗学的調査・考察がある程度。
進化論的意味のまとめ
本の骨子がここにある。
料理をしない民族はないこと。表１が興味深い。果物、葉、生肉を食べるとして、2000kcalを取得するためには、計算上2.9kgの食べ物を毎日摂らないといけないこと。基本的に不可能。少なくとも人間は生の食べ物を食べるようには適応していない。料理をすると栄養の吸収率が飛躍的に高まるので、それによって、生理学的な進化、腸の短縮、大脳の肥大化などが起こったと考える。
アメリカのハイカーには、軽量化のためにストーブを省略し、ジップロックに食料を入れて水でふやかして食べる人がいる。重量削減には合理的な方法であるが、栄養摂取の観点から見ると、吸収率が低くなってしまうので注意が必要である。Some American hiker omit a stove for a weight saving, put food into a zip lock pack, soak it with water and eat it . It may be a rational technique to weight reduction, but the absorption rate of nutrition in our body will become low. Cautions are required, from a viewpoint of nutrition
Comp Biochem Physiol A Mol Integr Physiol. 2003 Sep;136(1):35-46.
'Cooking as a biological trait'.
Wrangham R1, Conklin-Brittain N.
Abstract
No human foragers have been recorded as living without cooking, and people who choose a 'raw-foodist' life-style experience low energy and impaired reproductive function. This suggests that cooking may be obligatory for humans. The possibility that cooking is obligatory is supported by calculations suggesting that a diet of raw food could not supply sufficient calories for a normal hunter-gatherer lifestyle. In particular, many plant foods are too fiber-rich when raw, while most raw meat appears too tough to allow easy chewing. If cooking is indeed obligatory for humans but not for other apes, this means that human biology must have adapted to the ingestion of cooked food (i.e. food that is tender and low in fiber) in ways that no longer allow efficient processing of raw foods. Cooking has been practiced for ample time to allow the evolution of such adaptations. Digestive adaptations have not been investigated in detail but may include small teeth, small hind-guts, large small intestines, a fast gut passage rate, and possibly reduced ability to detoxify. The adoption of cooking can also be expected to have had far-reaching effects on such aspects of human biology as life-history, social behavior, and evolutionary psychology. Since dietary adaptations are central to understanding species evolution, cooking appears to have been a key feature of the environment of human evolutionary adaptedness. Further investigation is therefore needed of the ways in which human digestive physiology is constrained by the need for food of relatively high caloric density compared to other great apes.
卵の消化率
火を通すと91%、生卵は51%。放射性同位元素を使った実験。これは恐怖の結果。必ず火を通して食べた方がよい。
J Nutr. 1998 Oct;128(10):1716-22.
Digestibility of cooked and raw egg protein in humans as assessed by stable isotope techniques.
Evenepoel P1, Geypens B, Luypaerts A, Hiele M, Ghoos Y, Rutgeerts P.
Abstract
Egg proteins contribute substantially to the daily nitrogen allowances in Western countries and are generally considered to be highly digestible. However, information is lacking on the true ileal digestibility of either raw or cooked egg protein. The recent availability of stable isotope-labeled egg protein allowed determination of the true ileal digestibility of egg protein by means of noninvasive tracer techniques. Five ileostomy patients were studied, once after ingestion of a test meal consisting of 25 g of cooked 13C- and 15N-labeled egg protein, and once after ingestion of the same test meal in raw form. Ileal effluents and breath samples were collected at regular intervals after consumption of the test meal and analyzed for 15N- and 13C-content, respectively. The true ileal digestibility of cooked and raw egg protein amounted to 90.9 +/- 0.8 and 51.3 +/- 9.8%, respectively. A significant negative correlation (r = -0.92, P < 0.001) was found between the 13C-recovery in breath and the recovery of exogenous N in the ileal effluents. In summary, using the 15N-dilution technique we demonstrated that the assimilation of cooked egg protein is efficient, albeit incomplete, and that the true ileal digestibility of egg protein is significantly enhanced by heat-pretreatment. A simple 13C-breath test technique furthermore proved to be a suitable alternative for the evaluation of the true ileal digestibility of egg protein.
挽肉にしたり火を通すと消火のエネルギーが少なくてすむ
蛇を使った実験だが、ハンバーグなどが消化吸収に優れていることになる。
omp Biochem Physiol A Mol Integr Physiol. 2007 Nov;148(3):651-6. Epub 2007 Aug 16.
Cooking and grinding reduces the cost of meat digestion.
Boback SM1, Cox CL, Ott BD, Carmody R, Wrangham RW, Secor SM.
Abstract
The cooking of food is hypothesized to have played a major role in human evolution partly by providing an increase in net energy gain. For meat, cooking compromises the structural integrity of the tissue by gelatinizing the collagen. Hence, cooked meat should take less effort to digest compared to raw meat. Likewise, less energy would be expended digesting ground meat compared to intact meat. We tested these hypotheses by assessing how the cooking and/or grinding of meat influences the energy expended on its digestion, absorption, and assimilation (i.e., specific dynamic action, SDA) using the Burmese python, Python molurus. Pythons were fed one of four experimental diets each weighing 25% of the snake's body mass: intact raw beef, intact cooked beef, ground raw beef, and ground cooked beef. We measured oxygen consumption rates of snakes prior to and up to 14 days following feeding and calculated SDA from the extra oxygen consumed above standard metabolic rate. Postprandial peak in oxygen consumption, the scope of peak rates, and SDA varied significantly among meal treatments. Pythons digesting raw or intact meals exhibited significantly larger postprandial metabolic responses than snakes digesting the cooked ground meals. We found cooking to decrease SDA by 12.7%, grinding to decrease SDA by 12.4%, and the combination of the two (cooking and grinding) to have an additive effect, decreasing SDA by 23.4%. These results support the hypothesis that the consumption of cooked meat provides an energetic benefit over the consumption of raw meat.
Low Protein diet
theguadianで引用されたLow Protein Dietが65歳以下で、成長ホルモンのレセプター、癌、死亡率を引き下げるという論文、ただ、65歳以上には当てはまらない。
アメリカ人6,381名を対象にした疫学研究、平均年齢は65歳、NHANES IIIで死亡を18年間フォローアップした。死亡率は40%
This was an epidemiological study of 6,381 US people. mean age is 65 years. Mortality follow-up was carried out by NHANES III, The followup period is 18 years. 40% overall mortality.
最初の図はタンパク質摂取量と死亡率の関係、タンパク質制限食の利点は大きいが、65歳以下に限られる。動物性タンパク質の摂取量は統計的にコントロールされている。
The first figures are depicted as protein intake and mortality. Low protein diet is beneficial but not in old age, Animal protein was controlled for this figure.
2番目の図はマウスでの研究。高タンパク食は癌の成長を促進する。しかし、高齢のマウスでは低タンパク食が体重を低下させる。研究者によると、高齢ではタンパク質制限食の利点がなくなり、欠点となってしまうという。
The second figures were based on mice study. High protein diet facilitated the growth of cancer. But in old mice, low protein diet reduced their body weight. They said that the beneficial effects of protein restriction on morality into negative effects.
Summary
Mice and humans with growth hormone receptor/IGF-1 deficiencies display major reductions in age-related diseases. Because protein restriction reduces GHR-IGF-1 activity, we examined links between protein intake and mortality. Respondents aged 50–65 reporting high protein intake had a 75% increase in overall mortality and a 4-fold increase in cancer death risk during the following 18 years. These associations were either abolished or attenuated if the proteins were plant derived. Conversely, high protein intake was associated with reduced cancer and overall mortality in respondents over 65, but a 5-fold increase in diabetes mortality across all ages. Mouse studies confirmed the effect of high protein intake and GHR-IGF-1 signaling on the incidence and progression of breast and melanoma tumors, but also the detrimental effects of a low protein diet in the very old. These results suggest that low protein intake during middle age followed by moderate to high protein consumption in old adults may optimize healthspan and longevity.
