Milk is a useful test meal for measurement of small bowel transit time

Influence of Milk on Exhaled Carbon Monoxide (CO) Measurement by Portable CO Monitors

Background

A portable breath carbon monoxide (CO) monitor has a high cross-sensitivity to hydrogen (H₂). This study examined the influences of H₂ after consuming milk on the detected CO values using three types of portable CO monitors.

Materials and Methods

Exhaled breath from seven participants (four healthy nonsmokers and three smokers with otherwise unknown comorbidities) was collected in sampling bags. The participants then consumed 200 mL of milk, and the exhaled breath of each was collected in separate bags every 30 minutes until 9 hours later. CO and H₂ in the bag were measured using a gas chromatograph as a reference analyzer, and CO was also measured using three types of portable CO monitors.

Results

After consuming milk, H₂ levels were significantly higher, and CO levels were not significantly elevated as measured by the reference analyzer. However, CO levels in monitors A and B were significantly elevated, even though participants did not smoke. The H₂ levels in the reference analyzer significantly increased and reached a maximum 4.5 hours after consuming milk. The difference in CO levels between the reference analyzer and each monitor increased significantly after 5 or 5.5 hours.

Conclusions

This study suggested that the breath CO monitors with a cross-sensitivity to H₂ responded to H₂ as CO in the exhaled gas and measured higher than actual values after milk consumption. The extent of the influence of H₂ differed depending on the type of CO monitor. It is necessary to consider milk consumption when assessing the smoking status of people using portable CO monitors.

Seasonal variation in amount of unabsorbed dietary carbohydrate from the intestine after breakfast in young female Thai subjects: comparison with that of Japanese subjects

Previously, using the breath hydrogen test, we investigated seasonal variations in the amount of unabsorbed dietary carbohydrate from the intestine after breakfast in female Japanese university students and young Polish subjects. In the study we found that there were significant seasonal variations in both countries with the smallest unabsorbed dietary carbohydrate in autumn and the biggest in winter. Considering the theory of human adaptation to living environments, we suggested a hypothesis that this seasonal variation in the efficiency of carbohydrate absorption in the intestine may reflect human adaptation and/or a response to seasonal change in the living environment. In order to prove this hypothesis, we carried out the same examination in Chiang Mai, Thailand, where there is different seasonal change in the living environment from that of Japan and of Poland. In this examination, we measured the amount of unabsorbed dietary carbohydrate (UDC) from the intestine after breakfast and the oro-cecal transit time (OCTT) of the breakfast in female Thai university students using the same method and experimental protocol as previously carried out with Japanese subjects. We conducted the examination in April (the hot season), in August-September (the rainy season), and in November-December (the dry season) of 2008, at the Medical School of Chiang Mai University, Chiang Mai. The results are summarized as follows: (1) there were no significant seasonal variations in the amounts of unabsorbed dietary carbohydrate from breakfast in Thai subjects; (2) there were no significant seasonal variations in the oro-cecal transit times of breakfast or a soluble indigestible trisaccharide (lactosucrose) solution in Thai subjects; (3) there were no significant differences in the oro-cecal transit times of breakfast between the two countries in any season; (4) the UDC of Thai subjects was significantly less than that of the Japanese subjects in the three seasons. These results suggest that differences in seasonal change in a living environment have different effects on seasonal variations in the efficiency of carbohydrate absorption in the intestine after breakfast.

Seasonal Variation in the Amount of Dietary Carbohydrate Not Absorbed from the Intestine after Breakfast in Elderly Japanese Females

It was previously shown that there is seasonality in the amount of dietary carbohydrate not absorbed from the intestine after breakfast, the amount of carbohydrate in winter being significantly larger than that in autumn in young Japanese subjects. In order to investigate this phenomenon further, the experiment was repeated on 22 elderly Japanese female subjects (61-78 yrs of age) during the four seasons of the year. The amount of unabsorbed dietary carbohydrate by the breath hydrogen test, which measures the amount of hydrogen in exhaled air, was then estimated. A 6 g solution of lactosucrose, an indigestible trisaccharide, was used for comparison. Two groups of subjects, 16 subjects in Osaka and 6 subjects in Nagano, were studied in the summer (July to August) and autumn (October to November) of 2005 and the winter (January to February) and spring (April to May) of 2006. The following results were found using the pooled data of the total of 22 subjects. With regard to the amount of breath hydrogen excretion of the lactosucrose solution, there was no significant difference between the four seasons. There was a significant seasonal change in the efficiency of dietary carbohydrate absorption from the intestine after breakfast. The percentage of total carbohydrate that was not absorbed was lowest in the spring and highest in the winter. A comparison of the results from studies on the elderly and young subjects revealed the percentage of total carbohydrate that was not absorbed in the elderly was significantly lower than in the young in the winter, spring, and summer. These results indicate that there is seasonal variation in the efficiency of dietary carbohydrate absorption from the intestine among elderly female Japanese subjects as well as young female Japanese subjects. They also suggest that the efficiency of dietary carbohydrate absorption from the intestine after breakfast is retained in these naturally active and healthy elderly subjects.

Breath hydrogen produced by ingestion of commercial hydrogen water and milk

OBJECTIVE

To compare how and to what extent ingestion of hydrogen water and milk increase breath hydrogen in adults.

METHODS

Five subjects without specific diseases, ingested distilled or hydrogen water and milk as a reference material that could increase breath hydrogen. Their end-alveolar breath hydrogen was measured.

RESULTS

Ingestion of hydrogen water rapidly increased breath hydrogen to the maximal level of approximately 40 ppm 10-15 min after ingestion and thereafter rapidly decreased to the baseline level, whereas ingestion of the same amount of distilled water did not change breath hydrogen (p < 0.001). Ingestion of hydrogen water increased both hydrogen peaks and the area under the curve (AUC) of breath hydrogen in a dose-dependent manner. Ingestion of milk showed a delayed and sustained increase of breath hydrogen in subjects with milk intolerance for up to 540 min. Ingestion of hydrogen water produced breath hydrogen at AUC levels of 2 to 9 ppm hour, whereas milk increased breath hydrogen to AUC levels of 164 ppm hour for 540 min after drinking.

CONCLUSION

Hydrogen water caused a rapid increase in breath hydrogen in a dose-dependent manner; however, the rise in breath hydrogen was not sustained compared with milk.

Identification of gas emanated from human skin: methane, ethylene, and ethane

We investigated whether methane, ethylene and ethane gas can be detected in gas emanating from human skin, which is called skin gas. Skin gas was collected with a homemade stainless-steel trap system, which was cooled with liquid nitrogen, and analyzed with a gas chromatograph fitted with a flame ionization detector (FID). Skin-gas samples were obtained by covering a hand for 30 min with a polyfluorovinyl bag in which pure helium gas was introduced. The bag, the trap system and GC were set up online to avoid any contamination by air. Methane, ethylene and ethane in skin gas were successfully collected at an average amount emanated for 30 min (from ten subjects) of 150 +/- 63, 20 +/- 11 and 17 +/- 8 [mean +/- SD] pg/cm2, respectively.

Seasonal variation in amount of unabsorbed dietary carbohydrate from the intestine after breakfast in Japanese subjects

We previously showed that daytime dim-light exposure has a negative effect on the efficiency of dietary carbohydrate absorption in the evening, whereas evening-time dim-light exposure has a beneficial effect. These results suggest that seasonal changes in the environmental light may affect gastrointestinal activity, and that there might, therefore, be seasonal variation in the efficiency of dietary carbohydrate absorption from the intestine. In order to prove this hypothesis, we measured the amount of dietary carbohydrate unabsorbed from the intestine after a breakfast in healthy female Japanese subjects during the four seasons of the year. We estimated the amount of unabsorbed dietary carbohydrate by the breath hydrogen test, which measures the amount of hydrogen in exhaled air. A 6 g solution of lactosucrose, an indigestible trisaccharide, was used for comparison. Two groups of subjects, 12 subjects in Osaka and 14 subjects in Nagano, were studied in the winter (January to February), spring (April to May), summer (July to August), and autumn (October to November) of 2004. We found the following results: (1) In no season were there any significant differences between the two subgroups in the orocecal transit time of the breakfast and the lactosucrose solution. Nor were there any significant differences in the amount of unabsorbed dietary carbohydrate from the breakfast. (2) Using the pooled data of the total of 26 subjects, there was no significant seasonal variation in the orocecal transit time of the breakfast or the lactosucrose solution. (3) There was a significant seasonal variation in the amount of unabsorbed dietary carbohydrate from the breakfast. (4) The amount of unabsorbed dietary carbohydrate from the breakfast was largest in winter and smallest in autumn. Results in spring and in summer were similar and intermediate between those in winter and autumn. Post hoc multiple comparison tests showed that the amount of unabsorbed dietary carbohydrate in winter was significantly larger than in autumn. (5) In winter, the average ratio of the amount of unabsorbed dietary carbohydrate to the total amount of carbohydrate in the breakfast was about 12%; in autumn it was about 6%. These results clearly show that there is seasonal variation in the efficiency of intestinal dietary carbohydrate absorption among young female Japanese subjects.

Comparison of carbohydrate digestion between Japanese and Polish healthy subjects

We have revealed that light environment affects digestion and absorption of dietary carbohydrates in the gastrointestinal tract. This experimental result supposes that the efficiency of carbohydrate absorption may differ among people who live in different latitudes, such as Japanese and Polish people, at the same calendar season. In order to prove this hypothesis, we have been comparing the efficiency of carbohydrate absorption using the breath hydrogen test in Japan and Poland. Here, we report the comparison of the result obtained in the summer of 2004 as the following; (1) Orocecal transit time (OCTT) for indigestible trisaccharide of Japanese subjects was significantly longer than that in Poland (p = 0.043). (2) On the ingestion of minestrone, the amount of unabsorbed carbohydrate of Japanese subjects (which was estimated as trisaccharide equivalent) was significantly larger than that of Polish subjects (p = 0.006).

Effect of skin pressure by clothing on small bowel transit time

We examined the effect of increased skin pressure from tight clothing on small bowel transit time by means of the breath hydrogen test, using milk that contained lactulose as an additional indigestible disaccharide, which is used as a test meal after overnight fasting. In this experiment, we measured the small bowel transit time from 9 healthy and non-constipated female subjects with two different skin pressures that were applied by loose-fitting experimental garment or an additional tight-fitting girdle on two consecutive days. The skin pressure of the latter condition was 8-9 mmHg higher than that of the former one on the participants' waist, abdomen and hip region. The experimental order of the two skin pressure conditions was counterbalanced. As a result, the small bowel transit time obtained with and without girdle did not differ significantly (165.0 +/- 26.0 minutes for less skin pressure condition and 173.3 +/- 26.8 minutes for more skin pressure condition, n = 9, p = 0.43). This result indicated that the skin pressure from clothing has no effect on the passage rate of food through the small intestine.

Small bowel transit time and colonic fermentation in young and elderly women

Small bowel transit time (SBTT) in 15 young and 13 elderly women was assessed by measuring breath hydrogen concentrations after they had consumed a solid test meal. The meal consisted of 200 g cooked rice, 50 ml miso (made from fermented soy bean curd) soup, a boiled egg, and 95.5 g of cooked soy beans with mixed vegetables. This meal provided 17 g protein, 14.1 g fat, 92.9 g carbohydrate, 7 g dietary fiber, and 565 kcal total energy. The SBTT, calculated by a mean 3 ppm increase in breath hydrogen, was 191 +/- 14.9 (mean +/- SE) min in the young and 188.1 +/- 16.8 min in the elderly group; the difference was not significant. Breath hydrogen levels, however, were higher in the young than in the elderly group (39.1 +/- 6.3 ppm, vs 22.2 +/- 4.3 ppm, P < 0.05). There was an initial peak of hydrogen concentration, reached almost immediately after the ingestion of the meal, and then a decline to baseline within 60 min. This initial peak was not as pronounced in the elderly subjects. A second peak, indicating the entry of the test meal into the cecum, was more pronounced in the young than in the elderly group. SBTT did not differ significantly between the two groups, but colonic fermentation was more pronounced in the young, both in the fasting and the postprandial state.