Measurement of ambient gamma dose rate in Metro Manila, Philippines, using a portable NaI(TI) scintillation survey meter.

Radiological data such as ambient dose equivalent rate obtained from radiation monitoring in Metro Manila are useful for the detection of any anomalous increase of radiation dose rate levels due to nuclear or radiological emergencies. In this study, ambient dose equivalent rates were measured in different locations in Metro Manila using a portable NaI(Tl) scintillation survey meter to determine the background radiation levels within the capital. Ambient dose equivalent rates measured range from 32.7 ± 2.2 to 59.3 ± 8.7 nanosieverts per hour (nSv/h) with computed mean and median values of 41.7 and 39.6 nSv/h, respectively. These values were lower than the Philippines' average dose rate which is 52 nanograys per hour (nGy/h). No significant trend was also observed in the monthly variation of ambient dose equivalent rate for most locations, with the dose rates being relatively consistent throughout a year. No significant trend was further observed in the monthly variation of ambient dose equivalent rate for the whole Metro Manila. Data obtained in this study were used to develop a dose rate distribution map of Metro Manila which could be used as a baseline reference of emergency responders for environmental radioactivity monitoring during nuclear or radiological emergencies that may affect Metro Manila.

The effect of apparent amylose content and dietary fibre on the glycemic response of different varieties of cooked milled and brown rice.

Brown rice is a good source of dietary fibre (DF) and contains higher vitamins/minerals than milled rice. The study determined the effect of amylose content (AC) and DF on glucose response (GR) from different varieties of milled and brown rice. Milled and brown rice were used as test foods. They were fed to 9-10 human volunteers containing 50 g available carbohydrate after an overnight fast. GR and the glycemic index (GI) were determined. Results found that Sinandomeng with the lowest AC had a high GI = 75, while PSBRc10 with the highest AC had a low GI = 50. Sinandomeng with a low DF had GI = 75, while its brown rice had GI = 55. Brown rice (IR64) with 23% AC and DF of 2.5 g/100 g had low GI = 51. In conclusion, the GR and GI of the different varieties of cooked milled and brown rice varied depending on its AC and DF contents.

The potential health benefits of legumes as a good source of dietary fibre.

Dietary fibre has been shown to have important health implications in the prevention of risks of chronic diseases. The objective of the present study was to determine the potential health benefits of legumes as a good source of dietary fibre. Six to ten local legumes were studied as follows: cowpeas, mung beans, pole sitao, chickpeas, green peas, groundnuts, pigeon peas, kidney beans, lima beans and soyabeans. The following studies were conducted: (a) mineral availability, in vitro; (b) glycaemic index (GI) in non-diabetic and diabetic human subjects; (c) the cholesterol-lowering effect in human subjects with moderately raised serum cholesterol levels. The highest Fe availability among legumes was for lima beans (9.5 (sem 0.1)) while for Zn and Ca, the highest availability was for kidney beans (49.3 (sem 4.5)) and pigeon peas (75.1 (sem 7.1)), respectively. Groundnuts have the lowest Fe (1.3 (sem 1.1)), Zn (7.9 (sem 1.3)) and Ca (14.6 (sem 2.8)) availability. Legumes are low-GI foods ( < 55), ranging from 6 (chickpeas) to 13 (mung beans). Kidney beans showed significant reductions for both total (6 %) and LDL-cholesterol (9 %), and groundnuts for total cholesterol (7 %; P < 0.05). We conclude that mineral availability from legumes differs and may be attributed to their mineral content, mineral-mineral interaction and from their phytic and tannic acid content; legumes are considered low-GI foods and have shown potential hypocholesterolaemic effects. The above studies can be a scientific basis for considering legumes as functional foods.

Iron absorption from brown rice/brown rice-based meal and milled rice/milled rice-based meal.

BACKGROUND: Milled rice is the staple food among Filipinos and is mostly consumed three times a day. Rice as a source of iron could therefore have an important role in the existing 37% prevalence of iron-deficiency anemia in the country. Previous iron absorption studies in Filipinos from rice and rice-based meals were carried out on milled rice but no research was done on brown rice of the same variety. This leads to the hypothesis that brown rice may be better than milled rice in terms of iron content. OBJECTIVE: To determine iron absorption from brown rice and brown rice-based meal, and from milled rice and milled rice-based meal of the same variety. METHODS: The rice variety used in the study was F(2) seeds of PSB Rc72H. Iron absorption from brown/milled rice and brown/milled rice-based meals was determined in 12 healthy human subjects from the incorporation of radioisotopes of iron into erythrocytes 14 days after administration of the labeled rice/rice-based meals. The above samples were also analyzed for nutrient content, including dietary fiber, and iron. RESULTS: The iron content of brown rice was significantly higher (1.1 +/- 0.1 mg/100 g) than that of milled rice (0.6 +/- 0.1 mg/100 g). Brown rice has significantly greater amounts of total dietary fiber (5.4 +/- 0.4%) than milled rice (1.7 +/- 0.2%; P < 0.05). Both tannic acid and phytic acid contents in brown rice (56.9 +/- 3.2 mg/100 g and 290.1 +/- 18.0 mg/100 g, respectively) were significantly higher than those of milled rice (21.3 +/- 2.3 mg/100 g and 84.0 +/- 12.4 mg/100 g, respectively; P<0.05). The amount of iron absorbed from brown rice (0.13 +/- 0.02 mg) did not differ significantly from that from milled rice (0.14 +/- 0.02 mg). However, the amount from brown rice-based meal (0.36 +/- 0.04 mg) differed significantly from that from brown rice (P<0.05) as well as that from milled rice-based meal (0.35 +/- 0.03 mg) from that from milled rice (P<0.05). Moreover, brown rice-based meal did not differ significantly from milled rice-based meal (P<0.05). CONCLUSION: Iron absorbed from milled rice and brown rice did not differ significantly, as well as that from brown rice-based meal and milled rice-based meal. Differences in iron absorbed from brown/milled rice and brown/milled rice-based meals may be due to the iron content of the test foods and the presence of iron enhancers in the meal (e.g. fish, vegetables and citrus fruit).