Water Intake and Hydration Status among Pregnant Women in the Second Trimester in China: A Three-Day Metabolic Trial.

Adequate water intake and optimal hydration status during pregnancy are crucial for maternal and infant health. However, research on water intake by pregnant women in China is very limited. This study mainly aimed to observe the daily total water intake (TWI) of pregnant women and its different sources and to investigate the relationship between their water intake and hydration biomarkers. From October to November 2020, a convenience sample of pregnant women in the second trimester (n = 21) was recruited. Under conditions close to daily life, they undertook a 3-day metabolic trial. Each participant was provided with sufficient bottled water, and the weight of what they drank each time was measured. The intake of other beverages and foods was measured using a combination of weighing and duplicate portion method. Fasting venous blood and 24 h urine samples were collected and analyzed for the hydration biomarkers, including the serum/urine osmolality, urine pH, urine specific gravity, and the concentrations of major electrolytes in urine and serum. The results showed that the mean daily TWI was 3151 mL, of which water from beverages and foods accounted for 60.1% and 39.9%, respectively. The mean total fluid intake (TFI) was 1970 mL, with plain water being the primary contributor (68.7%, r = 0.896). Among the participants, 66.7% (n = 14, Group 1) met the TWI recommendation set by the Chinese Nutrition Society. Further analysis revealed that the TFI, water from beverages and foods, plain water, and milk and milk derivatives (MMDs) were significantly higher in Group 1 than those who did not reach the adequate intake value (Group 2) (p < 0.05). The results of hydration biomarkers showed that the mean 24 h urine volume in Group 1 was significantly higher than that in Group 2 (p < 0.05), while the 24 h urine osmolality, sodium, magnesium, phosphorus, chloride, and creatinine concentrations in Group 1 were significantly lower than those in Group 2 (p < 0.05). However, no significant differences were observed in serum biomarkers. Partial correlation analysis showed that TWI was moderately positively correlated with 24 h urine volume (r = 0.675) and negatively correlated with urine osmolality, sodium, potassium, magnesium, calcium, phosphorus, and chloride concentrations (r = from-0.505 to -0.769), but it was not significantly correlated with serum biomarkers. Therefore, under free-living conditions, increasing the daily intake of plain water and MMDs is beneficial for pregnant women to maintain optimal hydration. The hydration biomarkers in urine are more accurate indicators of water intake and exhibit greater sensitivity compared to serum biomarkers. These findings provide a scientific basis for establishing appropriate water intake and hydration status for pregnant women in China.

Impact of DHA from Algal Oil on the Breast Milk DHA Levels of Lactating Women: A Randomized Controlled Trial in China.

Population research on the intervention of docosahexaenoic acid (DHA) supplementation in lactating women is in its infancy in China. This study investigated the effect of DHA supplementation on DHA concentrations in the breast milk of lactating women, and the intervention effect, with respect to different dietary patterns. In this trial, 160 healthy lactating women in Nanjing (30−50 days postpartum) were recruited and randomly divided into control (one placebo capsule of similar appearance per day) and supplement (one capsule with 200 mg of DHA from algal oil per day) groups for 8 weeks. Before and after the intervention, all subjects were asked to maintain basic information, maternal anthropometric parameters, breast milk (10−15 mL) sample collection, and a dietary survey using a food frequency questionnaire. The concentrations of DHA and other fatty acids in breast milk were detected using capillary gas chromatography. This study was completed by 137 subjects, with 60 in the control group and 77 in the supplement group. Compared with the DHA concentrations in the breast milk at enrollment, the absolute concentrations of the control group showed a significant decrease at the end of the trial (p = 0.037). In addition, after intervention, the absolute and relative DHA concentrations in the supplement group (10.07 mg/100 mL and 0.40%, respectively) were higher than those in the control group (7.57 mg/100 mL and 0.28%, respectively), being statistically significant (p = 0.012 and p = 0.001). Furthermore, the maternal diet in the supplement group was divided into four dietary patterns. Pattern 1 mainly included fruits and livestock meat. Pattern 2 was dominated by milk and its products, eggs, fish, shrimp and shellfish, and soybeans and its products. Pattern 3 chiefly comprised cereal and beans other than soybeans, potatoes, and nuts. Pattern 4 was high in poultry meat and low in cooking oils. The change in the absolute concentration of DHA in Pattern 3 was lower than that in other patterns (p < 0.05). In conclusion, DHA supplementation in lactating mothers increased breast milk DHA concentrations. The dietary pattern mainly characterized by cereal and beans other than soybeans, potatoes, and nuts may contribute to the poor intervention effect.

Association between dietary fatty acid patterns based on principal component analysis and fatty acid compositions of serum and breast milk in lactating mothers in Nanjing, China.

This study aimed to comprehensively analyze dietary fatty acids (FAs) to evaluate their association with FA compositions of maternal serum and breast milk and assess their effects on mothers and infants. Overall, 121 healthy lactating Chinese mothers at 30-50 days of postpartum were enrolled and instructed to complete a Food Frequency Questionnaire, together with venous blood and breast milk sample collections. Dietary FA patterns were derived by principal component analysis with varimax rotation. Serum and breast milk FA compositions were detected using capillary gas chromatography and presented as relative concentrations (weight percentage of total FAs, %). Daily energy intake, absolute intake of most nutrients, and percentage of energy intake provided by these nutrients significantly varied among the different dietary FA patterns. There were significant differences in serum polyunsaturated fatty acid (PUFA) levels (P = 0.011); in monounsaturated fatty acid and PUFA proportions in breast milk with respect to four patterns (P = 0.002 and P = 0.026, respectively); and in n-6 PUFA, n-3 PUFA, linoleic acid, γ-linolenic acid, α-linolenic acid, and docosahexaenoic acid levels in breast milk (P = 0.027, P = 0.007, P = 0.048, P = 0.034, P = 0.020, and P = 0.002, respectively). Furthermore, maternal weight retention and length-for-age z scores, weight-for-age z scores and head circumference-for-age z scores of infants with respect to the four patterns exhibited significant differences (P = 0.038, P = 0.030, P = 0.034, and P<0.001, respectively). The results demonstrated the effect of dietary FA patterns on FA compositions of serum and breast milk, and patterns mainly characterized by LC-PUFA may have potentially beneficial effects on maternal postpartum recovery and infant growth.

Impact of Maternal Daily Oral Low-Dose Vitamin A Supplementation on the Mother-Infant Pair: A Randomised Placebo-Controlled Trial in China.

BACKGROUND: The nutritional status of vitamin A in lactating mothers and infants is still not optimistic. Due to the dietary habits and dietary restrictions of postpartum customs in China, vitamin A supplementation has been advocated as a potential strategy to improve vitamin A status of lactating mothers with inadequate dietary vitamin A intake. Existing clinical trials are limited to single or double high-dose maternal administrations. However, in China, vitamin A supplements are readily available in the form of daily oral low-dose supplements, and the effect of these is unknown. This study aimed to evaluate the effects of daily oral low-dose vitamin A supplementation on the retinol levels in the serum and breast milk of lactating mothers and the health status of infants in China. METHODS: Lactating mothers who met the inclusion criteria and planned to continue exclusive breastfeeding were randomly assigned to receive either daily oral vitamin A and D drops (one soft capsule of 1800 IU vitamin A and 600 IU vitamin D2), or a matching placebo for 2 months. Before and after the intervention, dietary intake was investigated by instant photography, and the retinol concentration in maternal serum and breast milk was determined by ultra-high performance liquid chromatography-tandem mass spectrometry. During the trial, the health status of infants was diagnosed by a paediatrician or reported by lactating mothers. A total of 245 participants completed the study, with 117 in the supplementation group and 128 in the control group. RESULTS: After the 2-month intervention, maternal serum retinol concentrations increased in the supplementation group with no change in the control group. Although breast milk retinol concentrations decreased significantly in both groups, the decrease in the supplementation group was significantly lower than that in the control group. However, maternal vitamin A supplementation was not associated with a lower risk of infant febrile illness, respiratory tract infection, diarrhoea, and eczema. CONCLUSIONS: Daily oral low-dose vitamin A supplementation is helpful in improving maternal vitamin A status, despite having no effect on infant health status through breast milk.

International experiences in assessing vitamin A status and applying the vitamin A-labeled isotope dilution method.

Inadequate vitamin A (VA) nutrition continues to be a major problem worldwide, and many interventions being implemented to improve VA status in various populations need to be evaluated. The interpretation of results after an intervention depends greatly on the method selected to assess VA status. To evaluate the effect of an intervention on VA status, researchers in Cameroon, India, Indonesia, Mexico, Senegal and Zambia have used serum retinol as an indicator, and have not always found improvement in response to supplementation. One problem is that homeostatic control of serum retinol may mask positive effects of treatment in that changes in concentration are observed only when status is either moderately to severely depleted or excessive. Because VA is stored mainly in the liver, measurements of hepatic VA stores are the “gold standard” for assessing VA status. Dose response tests such as the relative dose response (RDR) and the modified relative dose response (MRDR), allow a qualitative assessment of VA liver stores. On the other hand, the use of the vitamin A-labeled isotope dilution (VALID) technique, (using 13C or 2H-labeled retinyl acetate) serves as an indirect method to quantitatively estimate total body and liver VA stores. Countries including Cameroon, China, Ghana, Mexico, Thailand and Zambia are now applying the VALID method to sensitively assess changes in VA status during interventions, or to estimate a population’s dietary requirement for VA. Transition to the use of more sensitive biochemical indicators of VA status such as the VALID technique is needed to effectively assess interventions in populations where mild to moderate VA deficiency is more prevalent than severe deficiency.

[Effects of vitamin A supplementation on nutritional status of iron in healthy adults].

OBJECTIVE: To investigate the effect of vitamin A (VA) supplementation on the nutritional status of iron in healthy adults. METHODS: One hundred and fifteen healthy adults were recruited and divided randomly into four groups, with 28 or 29 adults in each group. VA supplements with different doses of retinyl acetate in capsules were given for 4-month. The equivalent doses of supplemented retinyl acetate were 600 microg/d, 400 microg/d, 200 microg/d and 0 microg/d (control) of retinol, respectively. The capsules were administered orally by double blind method. During the experiment, the subjects kept their usual dietary pattern but avoided high VA or pre-VA carotenoids foods from their diets. A 24-h dietary recall was carried out monthly on every subject. Before and after the intervention, the fast blood samples were collected from each subject, and were determined for hemoglobin concentration, levels of serum retinol, iron, ferrtin and transferrtin receptor. RESULTS: Total 108 subjects finished the experiment, with 27, 28, 27 and 26 persons left in group A, B, C and D, respectively. The subjects from each group had similar dietary intakes of energy nutrients, VA and iron (both were P > 0.05) during the experimental period. The serum retinol concentration of subjects from group A increased from 1.63 +/- 0.55 micromol/L of baseline to 1.93 +/-0.52 micromol/L at the end of the experiment (P < 0.05). The elevated value of serum retinol for group B and C were 0.29 micromol/L and 0.14 micromol/L (both were P < 0.05). There was no difference before and after the experiment for control group D (P > 0.05). There was no significant difference on Hb concentration before and after the experiment as well as between groups (all were P > 0.05). In subjects of group A, serum iron concentration increased (P < 0.05) and serum ferrtin and transferrtin receptor concentration decreased significantly (both were P < 0.05) after VA supplement intervention. No such changes were observed in group B and C (P < 0.05). CONCLUSION: It seems that the intervention of VA supplement with relative high dose of retinol at dietary level could enhance the iron status further in no-anemic healthy adults even without dietary iron supplementation.

Spirulina is an effective dietary source of zeaxanthin to humans.

Zeaxanthin is a predominant xanthophyll in human eyes and may reduce the risk of cataracts and age-related macular degeneration. Spirulina is an algal food that contains a high concentration of zeaxanthin. In order to determine the zeaxanthin bioavailability of spirulina for dietary supplementation in humans, spirulina was grown in nutrient solution with ²H2O for carotenoid labelling. Single servings of ²H-labelled spirulina (4.0-5.0 g) containing 2.6-3.7 mg zeaxanthin were consumed by fourteen healthy male volunteers (four Americans and ten Chinese) with 12 g dietary fat. Blood samples were collected over a 45 d period. The serum concentrations of total zeaxanthin were measured using HPLC, and the enrichment of labelled zeaxanthin was determined using LC-atmospheric pressure chemical ionisation-MS (LC-APCI-MS). The results showed that intrinsically labelled spirulina zeaxanthin in the circulation was detected at levels as low as 10 % of the total zeaxanthin for up to 45 d after intake of the algae. A single dose of spirulina can increase mean serum zeaxanthin concentration in humans from 0.06 to 0.15 µmol/l, as shown in our study involving American and Chinese volunteers. The average 15 d area under the serum zeaxanthin response curve to the single dose of spirulina was 293 nmol × d/µmol (range 254-335) in American subjects, and 197 nmol × d/µmol (range 154-285) in Chinese subjects. It is concluded that the relative bioavailability of spirulina zeaxanthin can be studied with high sensitivity and specificity using ²H labelling and LC-APCI-MS methodology. Spirulina can serve as a rich source of dietary zeaxanthin in humans.

[Interventional effect of vitamin A supplementation on re-vaccination to hepatitis B virus among rural infants and young children in China].

OBJECTIVE: The objective of this study was to observe the interventional effect of cod liver oil supplementation on re-vaccination to hepatitis B virus (HBV) among infants and young children. METHODS: All 7-36 months old infants and young children, who had been vaccinated with obligatory HBV vaccines routinely by the national technical and administrative procedures for HBV vaccination on children of China, were convened among villages in Linyi, Shandong province, from October 2008 to March 2009. After detection of serum anti-HBV, one hundred children with lower serum anti-HBV were picked out for the randomized, double blinded, placebo controlled vitamin A supplementation study. The children in the intervention group (50 subjects) took 0.5 g condensed cod liver oil (containing 25 000 IU vitamin A and 2500 IU vitamin D(2)) every 15 days for six times. The children in the control group (50 subjects) were given corn oil with same volume. All children were re-vaccinated at the 30th and the 60th day of the experiment. The serum samples were collected from each child at the 90th day of the experiment. Retinol concentration in serum samples was analyzed with HPLC method before and after the intervention. The levels of serum anti-HBs were detected by the electro-chemi-luminescence immunoassay (ECLIA). RESULTS: Total 74 children finished the supplemental experiment and blood collection, 37 subjects in each group, respectively. After intervention, the serum retinol level in the experimental and control group were (404.1 ± 123.1) and (240.8 ± 92.8) µg/L (t = 6.441, P < 0.01), respectively. The serum anti-HBs levels in the experimental and control group were (2737.2 ± 2492.6) and (1199.7 ± 2141.6) U/L (t = 2.846, P < 0.01), respectively. The rate of weak or no-answer case in experimental and control groups was 0.00% (0/37) and 10.81% (4/37) (χ(2) = 4.229, P = 0.040), respectively. CONCLUSION: The results showed that vitamin A supplementation might enhance the re-vaccination reaction against HB vaccine in infants and young children.

Vitamin A equivalence of spirulina beta-carotene in Chinese adults as assessed by using a stable-isotope reference method.

BACKGROUND: Spirulina is a high-protein food supplement that contains carotenoids. OBJECTIVE: The objective of the study was to determine the vitamin A equivalence of spirulina beta-carotene in humans. DESIGN: Spirulina was grown in a 23 atom% (2)H(2)O cultural solution. Spirulina beta-carotene showed the greatest enrichment as [(2)H(10)]trans beta-carotene. Ten healthy Chinese men with a mean (+/-SD) serum retinol concentration of 1.7 +/- 0.3 micromol/L and a body mass index (in kg/m(2)) of 23 +/- 3 consumed 5.8 micromol [(13)C(10)]retinyl acetate in oil as a reference dose with a breakfast containing 13 g fat. One week later, each subject consumed 7.9 mumol trans beta-carotene in spirulina with a breakfast containing 22 g fat. All subjects followed diets low in carotenoid and vitamin A. Forty blood samples were collected from each subject over a span of 56 d. Concentrations and enrichments of retinol and beta-carotene in serum samples were determined by using HPLC and a mass spectrometer. RESULTS: Compared with the serum response to [(13)C(10)]retinyl acetate dose, the mean conversion factor of spirulina beta-carotene to retinol was 4.5 +/- 1.6 (range: 2.3-6.9) by weight. It was estimated that 80% of the conversion occurred within the first 24 h after spirulina administration. CONCLUSION: In a group of well-nourished, normal-weight Chinese men following low-vitamin A diets, 4.5 mg spirulina beta-carotene consumed with 22 g fat has the same vitamin A activity as does 1 mg retinyl acetate.

[Evaluation on beta-carotene-vitamin A equivalence of middle-aged subjects in Chinese adults].

OBJECTIVE: As an extended study of beta-Carotene-vitamin A equivalence in Chinese adults, we carried out an experiment on 10 (5 males and 5 females) rural volunteers aged 38 - 49 years, which would be complementary to the early reported study on subjects aged 50 - 60 years. METHODS: Ten healthy Chinese adult volunteers aged 38-49 years were recruited in a 56 days experiment, which included residency in the Metabolic Research Unit (first 10 days and in home (last 46 days). A physiological dose of 2H8 beta-C (11,011 (nmole or 6 mg) in oil was given with a liquid diet (25% energy from fat) to the volunteers in the first day of the experiment. Three days after the 2H8 beta-C, each volunteer took a reference dose of 2H8 retinyl acetate (8,915 nmole or 3 mg) in oil with the same liquid diet. Serum samples were collected at 0, 3, 5, 7, 9, 11 and 13 hours of the first and the fourth days of study, and fasting serum samples were also collected daily in first 10 days and then weekly at morning of 14th, 21st, 28th, 35th, 42nd, 49th and 56th day after a 12-hours overnight fast. Serum retinol and carotenoids concentrations were measured by high performance liquid chromatography (HPLC). Also retinol fraction was extracted from serum and isolated by HPLC. The serum retinal enrichments were determined by using gas chromatograph/mass spectrometry with electron capture negative chemical ionization (GC-MS). RESULTS: The average 52-day area under the serum 2H4 retinol response curve (from the 2H8 beta-C dose) was (1289 +/- 547) nmol/d and the 52-day area under the serum 2H8 retinol response curve (from the 2H8 retinyl acetate dose) was (3560 +/- 1058) nmol/d. By using 2H8 retinyl acetate as the vitamin A reference, the 2H4 retinol formed from 2H8 beta-C (11,011 nmol) was calculated to be equivalent to (3434 +/- 1449) nmol of retinol. The calculated conversion factor of beta-C to retinol ranged from 2.00 - 9.61 to 1 with an average of (3.89 +/- 2.76) to 1 on a molar basis, or 3.76 - 18.05 to 1 with an average of (7.30 +/- 5.18) to 1 on a weight basis. CONCLUSION: The conversion of beta-C to vitamin A in 10 middle-aged Chinese adults had been quantitatively determined by using a stable isotope reference method, and an average conversion ratio of 7.30 : 1 to 1 on a weight basis was found in this study.