Dietary Sodium Intake in Patients with Type 2 Diabetes Mellitus

Association of sodium intake with diabetes in adults without hypertension: evidence from the National Health and Nutrition Examination Survey 2009-2018

Background

Sodium is essential for human health, however the prevalence of various diseases is associated with excessive sodium intake, particularly cardiovascular disorders. However, in most countries, salt intake is much higher than the World Health Organization recommends. Several studies in recent years have revealed that high salt intake is associated with diabetes in the general population, but the association is uncertain in people who do not have hypertension. In this study, we aimed to find out whether high sodium intake increases the risk of diabetes in this particular population.

Method

Data were extracted from the National Health and Nutrition Examination Survey (NHANES; 2009-2018). Participants included adults aged over 20 years old who have undergone the diabetes questionnaire, and the hypertension population was excluded. In order to adjust the confounders, multivariate analysis models were built. Finally, subgroup analysis were conducted to investigate the association between sodium intake and diabetes separately.

Result

In the present study, 7,907 participants are included (3,920 female and 3,987 male), and 512 (6.48%) individuals reported diabetes. The median sodium intake of the participants was 3,341 mg/d (IQR: 2498, 4,364 mg/d). A linear association between sodium intake and the prevalence of diabetes was found (p = 0.003). According to the multivariate analysis models, the odds ratio of diabetes for every 1,000 mg sodium intake increment is 1.20 (OR: 1.20, 95% CI 1.07-1.35). The highest sodium intake quartile was 1.80-fold more likely to have diabetes than the lowest quartile (OR: 1.80, 95% CI 1.17-2.76).

Conclusion

Our results suggest that higher sodium intake is associated with an increased risk of diabetes in the population without hypertension, and for every 1,000 mg sodium intake increment, the risk of diabetes increased by 1.20-fold. To sum up, we have provided the clue to the etiology of diabetes and further prospective research is needed to contribute recommendations for the primary prevention of diabetes in the US.

Effects of dietary salt intake restriction on blood glucose levels: a meta-analysis of crossover study

BACKGROUND/OBJECTIVES

To identify modifiable risk factors for type 2 diabetes mellitus and explore the relationship between diet sodium intake and blood glucose levels.

MATERIALS/METHODS

Based on inclusion and exclusion criteria, we extracted, analyzed, and assessed the available crossover studies of dietary salt intake restriction and insulin resistance in PubMed, Web of Science, MEDLINE, Embase, Wanfang, and CNKI databases.

RESULTS

We included 6 studies with 8 sets of data, covering 485 subjects. I² statistics results showed insignificant heterogeneity among all data (I² = 39.2% < 50%). Thus, a fixed-effect model was adopted for the final pooled effect size. Weighted mean difference and its 95% confidence interval (CI) value was 0.193 (95% CI, 0.129-0.257), and the test of the overall effect showed P < 0.001. The results revealed that the blood glucose levels in the subjects in the low-salt intake group were significantly higher than those in the normal or high-salt intake groups. We also found no significant change occurred after the removal of any study through sensitivity analysis, which confirmed that the outcome we calculated was prudent and credible. The quantitative Egger's test (P = 0.109 > 0.05) indicated that insignificant publication bias existed.

CONCLUSION

This meta-analysis highlights the relationship between dietary sodium intake and blood glucose levels. Our findings show that higher blood glucose levels might be expected in hypertensive or normal people with low-salt consumption compared to those with normal or high-salt consumption, although these differences were not clinically significant.

Trial Registration

PROSPERO Identifier: CRD42021256998.

Effects of different diets on glycemic control among patients with type 2 diabetes: A literature review

Background: Globally, type 2 diabetes mellitus (T2DM) is one of the most common diseases, and the incidence is gradually increasing. Diet management could improve the elevated HbA1c levels. Aim: This review aims to examine the effects of different types of diets on glycemic control in patients with T2DM. Methods: PubMed and Google scholar databases were searched. Reports published from the years 1991 to 2021 that focused on the effect of different diets on diabetes control were selected. Results: All the studies reported that the type of diet can affect insulin secretion and glycemic control in patients with diabetes. The recommended macronutrient distribution for patients with diabetes is 30% of fat, 45-60% of carbohydrates, and 15-35% of protein. Consuming more or less of these macronutrients may lead to changes in glucose metabolism and may affect insulin secretion. In fact, following alow-fat diet improves glycemic control and decreases HbA1c levels. Studies reported that a low-carbohydrate diet had the greatest effect on improving glycemic control and insulin parameters. A low-calorie diet reduced fasting plasma glucose, while a very low-calorie diet resulted in a long-term decrease in HbA1c level. A healthy diet free of processed foods and sugar, and rich in nutrients such as fiber, vitamins, and minerals contributed to maintaining controlled blood sugar and lipid plasma levels. Although studies show a low-salt diet improves blood pressure, which is common inT2DM, other findings show that restricting salt intake is associated with increased sugar consumption. Conclusion: Healthy diet with adequate intake of energy and low-fat and low-sugar foods can enhance the glycemic control and reduce T2DM complications.

Factors associated with salt intake in the Brazilian adult population: National Health Survey

This paper aims to identify the factors associated with high salt intake in the Brazilian adult population. This is a cross-sectional study with 8,083 adults participating in the National Health Survey (PNS, 2014/15). Salt intake was based on the estimation of 24-hour urinary sodium calculated from the sodium/creatinine ratio in spot urine samples. The highest quartile of the distribution was considered high salt intake. The relationship between high salt consumption and sociodemographic factors, lifestyles, morbidity, and self-rated health status was analyzed by calculating the crude prevalence ratios and the prevalence ratios adjusted for age and gender. Approximately 28.1% had an estimated salt intake higher than 10.56 g/day. Overweight (Adjusted Prevalence Ratio; 95%CI - PRadj 1.23; 1.09-1.39), obesity (PRadj 1.61; 1.43-1.83), and diabetes (PRadj 1.36; 1.17-1.58) were positively associated with high salt intake. Female gender (PRadj 0.73; 0.66-0.80), high schooling level (PRadj 0.88; 0.79-0.99), living in the North and chronic kidney disease (PRadj 0.71; 0.56-0.90) were protective factors. Salt consumption is elevated nationwide and in all population subgroups, requiring coordinated actions.

Associations of Dietary Salt and Its Sources with Hemoglobin A1c in Patients with Type 2 Diabetes Not Taking Anti-Diabetic Medications: Analysis Based on 6-Month Intervention with a Moderate Low-Carbohydrate Diet

OBJECTIVE

Based on biological studies, the hyperglycemic effect mediated by sodium-glucose co-transporter 1 in the intestine is stronger for foods containing more sodium chloride. Observational studies have demonstrated that type 2 diabetes (T2DM) incidence increases as salt intake increases. We aimed to elucidate associations of total salt and its sources with hemoglobin A1c (HbA1c) in patients with T2DM.

METHODS

We conducted an observational study using data from a 6-month moderate low-carbohydrate dietary intervention in 245 outpatients with T2DM (138 men) without antidiabetic medication. Intakes of total salt and its sources, carbohydrate and total energy were assessed at baseline and 6 months based on 3-day dietary records. Multiple regression analyses were performed to examine associations of Δtotal salt or its sources with ΔHbA1c.

RESULTS

Salt intake significantly decreased in men (change: -0.92 ± 3.53 g/day) but not in women (0.11 ± 2.28). HbA1c (men: -1.5 ± 1.6%; women: -0.9 ± 1.3%), carbohydrate (men: -115 ± 104 g/day; women: -64 ± 71) and total energy (men: -439 ± 660 kcal/day; women: -192 ± 438) significantly decreased in both sexes. Multiple regression analysis revealed that reducing intakes of total salt and salt from salty snacks, meat processed foods, Chinese noodles with soup and table salt by 1.0 g was associated with decreases in HbA1c of 0.11% 1.18% 0.47% 0.38% and 0.26%, respectively, in men, while reducing salt from miso by 1.0 g was associated with a decrease in HbA1c of 0.30% in women. The associations were dependent on Δcarbohydrate or Δtotal energy in men, while the association of Δsalt from miso in women was independent of them.

CONCLUSION

Reducing total salt and its sources had differential associations with HbA1c. Individual associations depended on Δcarbohydrate or Δtotal energy in men, while that of salt from miso in women was independent of them.