Development and internal validation of a non-invasive clinical tool to predict sufficient omega-3 levels in early pregnancy

BACKGROUND

Complications from preterm birth (PTB) are the leading cause of death and disability in those under five years. Whilst the role of omega-3 (n-3) supplementation in reducing PTB is well-established, growing evidence suggests supplementation use in those replete may increase the risk of early PTB.

AIM

To develop a non-invasive tool to identify individuals with total n-3 serum levels above 4.3% of total fatty acids in early pregnancy.

METHODS

We conducted a prospective observational study recruiting 331 participants from three clinical sites in Newcastle, Australia. Eligible participants (n = 307) had a singleton pregnancy between 8 and 20 weeks' gestation at recruitment. Data on factors associated with n-3 serum levels were collected using an electronic questionnaire; these included estimated intake of n-3 (including food type, portion size, frequency of consumption), n-3 supplementation, and sociodemographic factors. The optimal cut-point of estimated n-3 intake that predicted mothers with total serum n-3 levels likely above 4.3% was developed using multivariate logistic regression, adjusting for maternal age, body mass index, socioeconomic status, and n-3 supplementation use. Total serum n-3 levels above 4.3% was selected as previous research has demonstrated that mothers with these levels are at increased risk of early PTB if they take additional n-3 supplementation during pregnancy. Models were evaluated using various performance metrics including sensitivity, specificity, area under receiver operator characteristic (AUROC) curve, true positive rate (TPR) at 10% false positive rate (FPR), Youden Index, Closest to (0,1) Criteria, Concordance Probability, and Index of Union. Internal validation was performed using 1000-bootstraps to generate 95% confidence intervals for performance metrics generated.

RESULTS

Of 307 eligible participants included for analysis, 58.6% had total n-3 serum levels above 4.3%. The optimal model had a moderate discriminative ability (AUROC 0.744, 95% CI 0.742-0.746) with 84.7% sensitivity, 54.7% specificity and 37.6% TPR at 10% FPR.

CONCLUSIONS

Our non-invasive tool was a moderate predictor of pregnant women with total serum n-3 levels above 4.3%; however, its performance is not yet adequate for clinical use.

TRIAL REGISTRATION

This trial was approved by the Hunter New England Human Research Ethics Committee of the Hunter New England Local Health District (Reference 2020/ETH00498 on 07/05/2020 and 2020/ETH02881 on 08/12/2020).

Effects of individualized dietary advice compared with conventional dietary advice for adults with type 2 diabetes: A randomized controlled trial

BACKGROUND AND AIMS

To investigate the superiority of individualized dietary advice based on dietary assessment for patients with type 2 diabetes.

METHODS AND RESULTS

A total of 136 Japanese adults with type 2 diabetes were randomized into either individualized or conventional dietary advice groups after dietary assessment using a self-administered brief-type diet history questionnaire. Both participants received three 30-min face-to-face dietary advice sessions by dietitians at 1, 3, and 5 months from study entry. The individualized group received dietary advice based on individual dietary intakes. The conventional group received dietary advice using generalized pamphlets. The primary outcome was the change in HbA1c over 6 months, and secondary outcomes were changes in weight, serum triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and dietary intakes. In total, 126 participants were included in the analysis. After adjustment for age, sex, and baseline measurements, HbA1c significantly decreased larger in the individualized group [-1.1%, (95% CI: -1.3 to -0.8)] than the conventional group [-0.7% (95% CI: -1.0 to -0.4)] (P = 0.0495). The individualized group significantly decreased weight, serum triglyceride, and LDL-C, and significantly increased HDL-C, without a significant difference to the conventional group. In dietary changes, the individualized group decreased intakes of energy, confectioneries, meats, oil and fats, and sugar-sweetened beverages. The conventional group decreased alcohol intake and increased total fat and saturated fatty acid intakes.

CONCLUSIONS

Individualized dietary advice among patients with type 2 diabetes was superior to conventional dietary advice in lowering HbA1c.

TRIAL REGISTRATION

UMIN000037268 (https://www.umin.ac.jp/ctr/index.htm) in July 4, 2019.

Evaluation of protein and amino acid intake estimates from the EPIC dietary questionnaires and 24-h dietary recalls using different food composition databases

BACKGROUND AND AIMS

This study aimed to expand the European Prospective Investigation into Cancer and Nutrition (EPIC) nutrient database (ENDB) by adding amino acid (AA) values, using the U.S. nutrient database (USNDB). Additionally, we aimed to evaluate these new protein and AA intake estimates from the EPIC dietary questionnaires (DQ) and 24-h dietary recalls (24-HDR) using different matching procedures.

METHODS AND RESULTS

Dietary energy, protein and AA intakes were assessed via DQ and 24-HDR by matching with the USNDB food composition table. Energy and protein intakes calculated using USNDB matching were compared with those calculated using ENDB, that uses country specific food composition tables. Pearson correlations, Cohen's weighted kappa statistic and Bland-Altman plots were used to compare data resulting from USNDB matching with our reference from ENDB matching. Very high correlations were found when comparing daily energy (r = 0.99) and dietary protein intakes (r = 0.97) assessed via USNDB with those obtained via ENDB (matching for DQ and 24-HDR). Significant positive correlations were also found with energy and protein intakes acquired via 24-HDRs in the EPIC calibration sample.

CONCLUSION

Very high correlations between total energy and protein intake obtained via the USDA matching and those available in ENDB suggest accuracy in the food matching. Individual AA have been included in the extended EPIC Nutrient database that will allow important analyses on AA disease prospective associations in the EPIC study.

Associations between dietary amino acid intakes and blood concentration levels

BACKGROUND AND AIMS

Emerging evidence suggests a role of amino acids (AAs) in the development of various diseases including renal failure, liver cirrhosis, diabetes and cancer. However, mechanistic pathways and the effects of dietary AA intakes on circulating levels and disease outcomes are unclear. We aimed to compare protein and AA intakes, with their respective blood concentrations in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.

METHODS

Dietary protein and AA intakes were assessed via the EPIC dietary questionnaires (DQ) and 24-h dietary recalls (24-HDR). A subsample of 3768 EPIC participants who were free of cancer had blood AA concentrations measured. To investigate how circulating levels relate to their respective intakes, dietary AA intake was examined in quintiles and ANOVA tests were run. Pearson correlations were examined for continous associations between intakes and blood concentrations.

RESULTS

Dietary AA intakes (assessed with the DQ) and blood AA concentrations were not strongly correlated (-0.15 ≤ r ≤ 0.17) and the direction of the correlations depended on AA class: weak positive correlations were found for most essential AAs (isoleucine, leucine, lysine, methionine, threonine, tryptophan, and valine) and conditionally essential AAs (arginine and tyrosine), while negative associations were found for non-essential AAs. Similar results were found when using the 24-HDR. When conducting ANOVA tests for essential AAs, higher intake quintiles were linked to higher blood AA concentrations, except for histidine and phenylalanine. For non-essential AAs and glycine, an inverse relationship was observed. Conditionally-essential AAs showed mixed results.

CONCLUSIONS

Weak positive correlations and dose responses were found between most essential and conditionally essential AA intakes, and blood concentrations, but not for the non-essential AAs. These results suggest that intake of dietary AA might be related to physiological AA status, particularly for the essential AAs. However, these results should be further evaluated and confirmed in large-scale prospective studies.

Diet and Kidney Stones: The Ideal Questionnaire

Diet frequently contributes to patients' urinary stone disease. It is important to determine when this is the case and when it is not, as failure to do so may delay the implementation of other, more appropriate therapies. When diet is thought to be involved, one of two approaches may be taken: (1) provide a general list of all possible dietary factors that influence the risk for all types of stones and let the patient decide which dietary change(s) are needed; or (2) prescribe specific modifications that address each patient's need for change and their personal characteristics (i.e., urinary risk factors, type(s) of stones they have formed, dietary preferences, nutrient needs, etc.). The latter of these approaches is "minimally invasive" and is thus consistent with the goal of other therapies. However, this approach requires a rigorous appraisement of each patient's diet and linkage, when possible, to urinary and other stone risk factors. When the collaboration of a registered dietitian nutritionist or other nutrition professional experienced in dietary assessment is not available, screeners or questionnaires may be useful. Unfortunately, there is no such tool that is validated for identifying dietary stone risk factors. The development of a brief, 40-item, stone-specific food screener is described. While further validation is needed, it may provide the basis for a standardized instrument that could be used more broadly; desired features of such an instrument are described. Patient Summary: Personalized nutrition therapy is useful in mitigating the effects or recurrence risk of many chronic diseases. It is also useful in stone disease, a condition with highly variable risk expression, even among patients who form the same types of stones. A standardized and validated stone-specific dietary assessment tool would be valuable in clinical management and in research studies involving the description of patients' diets and dietary intervention.