Tomonori Nadamoto

Regulation of the peripheral body temperature by foods: a temperature decrease induced by the Japanese persimmon (kaki, Diospyros kaki).

We investigated whether the ingestion of the Japanese persimmon (kaki, Diospyros kaki) could lower the human peripheral body temperature. It was found that the temperatures recorded at the foot and wrist were depressed after kaki consumption compared to after the same amount of water consumption. The effects of ingesting freeze-dried kaki and eating a cookie (as its nutritional counterpart) containing the same amount of carbohydrate, protein, fat, and water were compared. A similar temperature-reducing effect of kaki was observed. The recovery of finger temperature after soaking the finger in ice-cooled water was also studied. The temperature recovery was delayed after kaki consumption. It was thus quantitatively demonstrated that ingesting kaki indeed had the effect of lowering (or repressing the rise) of the peripheral human body temperature, as has been traditionally believed in China for many hundreds of years.

Effects of α-Glucosylhesperidin on the Peripheral Body Temperature and Autonomic Nervous System

We studied the effects of α-glucosylhesperidin (G-Hsp) on the peripheral body temperature and autonomic nervous system in humans. We first conducted a survey of 97 female university students about excessive sensitivity to the cold; 74% of them replied that they were susceptible or somewhat susceptible to the cold. We subsequently conducted a three-step experiment. In the first experiment, G-Hsp (500 mg) was proven to prevent a decrease in the peripheral body temperature under an ambient temperature of 24 °C. In the second experiment, a warm beverage containing G-Hsp promoted blood circulation and kept the finger temperature higher for a longer time. We finally used a heart-rate variability analysis to study whether G-Hsp changed the autonomic nervous activity. The high-frequency (HF) component tended to be higher, while the ratio of the low-frequency (LF)/HF components tended to be lower after the G-Hsp administration. These results suggest that the mechanism for temperature control by G-Hsp might involve an effect on the autonomic nervous system.

Enhancement of Fat Oxidation by Licorice Flavonoid Oil in Healthy Humans during Light Exercise

Licorice flavonoid oil (LFO) is a new functional food ingredient consisting of hydrophobic licorice polyphenols in medium-chain triglycerides. Recent studies reported that LFO prevented and ameliorated diet-induced obesity via the regulation of lipid metabolism-related gene expression in the livers of mice and rats, while it reduced body weight in overweight human subjects by reducing total body fat. However, the direct effects of LFO on energy metabolism have not been studied in human subjects. Therefore, we investigated the effects of ingestion of LFO on energy metabolism, including fat oxidation, by measuring body surface temperature under resting conditions and respiratory gas analysis under exercise conditions in healthy humans. We showed that ingestion of a single 600 mg dose of LFO elevated body trunk skin temperature when measured in a slightly cooled air-conditioned room, and increased oxygen consumption and decreased the respiratory exchange ratio as measured by respiratory gas analysis during 40% Vo2max exercise with a cycle ergometer. Furthermore, repeated ingestion of 300 mg of LFO for 8 d decreased respiratory exchange during the recovery period following 40 min of 30% Vo2max exercise on a treadmill. These results suggest that LFO enhances fat oxidation in humans during light exercise.

Allyl isothiocyanate increases carbohydrate oxidation through enhancing insulin secretion by TRPV1

Abstract The transient receptor potential (TRP) V1 is a cation channel belonging to the TRP channel family and it has been reported to be involved in energy metabolism, especially glucose metabolism. While, we have previously shown that intragastric administration of allyl isothiocyanate (AITC) enhanced glucose metabolism via TRPV1, the underlying mechanism has not been elucidated. In this study, we examined the relationship between insulin secretion and the increase in carbohydrate oxidation due to AITC. Intragastric administration of AITC elevated blood insulin levels in mice and AITC directly enhanced insulin secretion from isolated islets. These observations were not reproduced in TRPV1 knockout mice. Furthermore, AITC did not increase carbohydrate oxidation in streptozotocin-treated mice. These results suggest that intragastric administration of AITC could induce insulin secretion from islets via TRPV1 and that enhancement of insulin secretion was related to the increased carbohydrate oxidation due to AITC. Intragastric administration of AITC could induce insulin secretion via TRPV1 and that insulin secretion was related to the increased carbohydrate oxidation due to AITC.

Deodorant Effect of Extracts from Wild Grasses against Methanethiol.

野草 (17科42種) を対象として, 悪臭指標物質の一つであるメタンチオール (CH3SH) に対する消臭力の有無を検索し, さらにその消臭力の比較検討を行った。野草から得られたメタノール抽出物5mgについて, ヘッドスペースガスクロマトグラフ法によりCH3SHに対する消臭率を求めた。その結果, 約1/3の14種の野草に, 銅クロロフィリンナトリウム (SCC) よりも高い消臭力が認められた。特に消臭率100%を示した野草は, オニアザミ, カワラヨモギ, タカサブロウ, ヒメジョン, カキドオシ, オオニシキソウ, キジムシロの7種類であった。これら7種の野草抽出物の中でも, タカサブロウはSCCの24倍, オニアザミ14倍, オオニシキソウ7倍, カワラヨモギが6倍となる高い消臭力であった。これらの野草が消臭性植物であるという報告はこれまでのところ見あたらない。したがって, これらの野草は新しく消臭効果の期待できる素材であることが示唆され, 今後その作用に寄与している成分の同定が必要と考えられる。