Plant- and Animal-Derived Dietary Sources of Phosphatidylcholine Have Differential Effects on Immune Function in The Context of A High-Fat Diet in Male Wistar Rats.

BACKGROUND: Phosphatidylcholine (PC) derived from eggs has been shown to beneficially modulate T cell response and intestinal permeability under the context of a high-fat diet. OBJECTIVES: The objective of this study was to determine whether there is a differential effect of plant and animal-derived sources of PC on immune function. METHODS: Four-week-old male Wistar rats were randomly assigned to consume 1 of 4 diets (n = 10/group) for 12 wk, all containing 1.5 g of total choline/kg of diet but differing in choline forms: 1-Control Low-Fat [CLF, 20% fat, 100% free choline (FC)]; 2-Control High-Fat (CHF, 50% fat, 100% FC); 3-High-Fat Egg-derived PC (EPC, 50% fat, 100% Egg-PC); 4-High-Fat Soy-derived PC (SPC, 50% fat, 100% Soy-PC). Immune cell functions and phenotypes were measured in splenocytes by ex vivo cytokine production after mitogen stimulation and flow cytometry, respectively. RESULTS: The SPC diet increased splenocyte IL-2 production after PMA+I stimulation compared with the CHF diet. However, the SPC group had a lower proportion of splenocytes expressing the IL-2 receptor (CD25+, P < 0.05). After PMA+I stimulation, feeding EPC normalized splenocyte production of IL-10 relative to the CLF diet, whereas SPC did not (P < 0.05). In mesenteric lymph node lymphocytes, the SPC diet group produced more IL-2 and TNF-α after PMA+I stimulation than the CHF diet, whereas the EPC diet group did not. CONCLUSIONS: Our results suggest that both egg- and soy-derived PC may attenuate high-fat diet-induced T cell dysfunction. However, egg-PC enhances, to a greater extent, IL-10, a cytokine involved in promoting the resolution phase of inflammation, whereas soy-PC appears to elicit a greater effect on gut-associated immune responses.

Potassium-Based Sodium Substitutes Impact the Sodium and Potassium Content of Foods.

OBJECTIVE: Potassium-based sodium substitutes (PBSS) can be used to replace sodium during food processing. How potassium and sodium content is associated with PBSS is not known. The objectives of the study were to describe the prevalence of PBSS by sodium content claim category and describe how PBSS are associated with sodium and potassium concentrations by sodium level. DESIGN AND METHODS: This cross-sectional analysis used the July 2018 version of the United States Department of Agriculture's Branded Food Products Database. Products were divided into sodium content claim category and were analyzed for the presence of PBSS. Products with nonmissing values for sodium and potassium were grouped by sodium level and analyzed for the prevalence of PBSS to explore potassium and sodium concentration. Column proportion z-test with the Bonferroni correction was used to explore the occurrence of PBSS by sodium content claim category. Mann-Whitney U-test was used to assess differences in potassium and sodium concentrations across sodium levels and within levels by the presence/absence of PBSS. RESULTS: The prevalence of PBSS in the categories "without a sodium content claim" (2.4%), "lightly salted" (0.5%), and "unsalted" claims (0.6%) were statistically significantly lower than prevalence of PBSS in the "sodium free" (9.5%), "low sodium" (10.3%), and "reduced sodium" claim categories (23.3%; all P < .01). Among the group of products with serving sizes more than 30 g containing PBSS, there was a 357 mg per serving higher median sodium concentration and a 160 mg per serving higher median potassium concentration compared to the group without PBSS (both P < .01). CONCLUSION: In the "reduced sodium" claim category, a higher prevalence of PBSS was found compared to other sodium claim categories. The presence of PBSS was associated with higher potassium and sodium concentrations in foods.

The Programming Effect of Plant-Based DHA, Along with Equivalent AA, on Immune System and Oral Tolerance Development in Six-Week Allergy Prone BALB/c Pups.

BACKGROUND: Docosahexaenoic acid (DHA) and arachidonic acid (AA) on oral tolerance (OT) development in allergy-prone infants is less known. OBJECTIVES: We aim to determine the effects of early life DHA supplementation (1% of total fat, from novel canola oil), along with AA, on OT toward ovalbumin (ova, egg protein) in allergy-prone BALB/c pups at 6-wk. METHODS: Breastfeeding dams (n ≥ 10/diet) were fed DHA+AA (1% DHA, 1% AA wt/wt of total fat) or control (0% DHA, 0% AA) suckling period diet (SPD) during which pups consumed dam's milk. At 3-wk, pups from each SPD group were assigned to either the control or DHA+AA weaning diet. For OT, pups from each diet group were either orally fed ova or placebo daily from 21-25 d. Systemic immunization to ova was induced through intraperitoneal injections before euthanizing 6-wk pups. Ova-specific immunoglobulin (ova-Ig) and splenocytes ex-vivo cytokine response to different stimuli were analyzed using a 3-factor analysis of variance. RESULTS: OT-induced suppression was seen in ova-stimulated splenocyte ex-vivo response, where ova-tolerized pups showed significantly lower total immunoglobulin (Ig)G, IgG1, interleukin (IL)-2 and IL-6 production than sucrose (placebo) pups. DHA+AA SPD was associated with 3 times lower plasma concentrations of ova-IgE (P = 0.03) than controls. DHA+AA weaning diet resulted in lower T helper type-2 cytokines (IL-4 and IL-6) with ova stimulation than controls, which may benefit OT. DHA+AA SPD resulted in significantly higher T cell cytokine response [IL-2, interferon-gamma, (IFNγ) and IL-1ß] to anti-CD3/CD28 stimulation than controls. The splenocytes stimulated with lipopolysaccharide produced lower inflammatory cytokines (IFNγ, tumor necrosis factor-alpha, IL-6, and C-X-C motif ligand 1), which may be because of lower CD11b+CD68+ splenocytes proportion in pups from DHA+AA SPD than control (all P < 0.05). CONCLUSIONS: DHA and AA in early life may influence OT in allergy-prone BALB/c mouse offspring, as they effectively promote T helper type-1 immune responses.

A Physiologically Relevant Dose of 50% Egg-Phosphatidylcholine Is Sufficient in Improving Gut Permeability while Attenuating Immune Cell Dysfunction Induced by a High-Fat Diet in Male Wistar Rats.

BACKGROUND: Obesity is associated with increased intestinal permeability and a diminished immune response. Phosphatidylcholine (PC), a form of choline found in eggs, has been shown to beneficially modulate T-cell response in the context of obesity when provided as the sole form of choline in the diet. OBJECTIVE: This study aimed to determine the impact of varying doses of PC as part of a high-fat diet (HFD) on immune cell function and intestinal permeability. METHODS: Male Wistar rats 4 wk of age were randomly assigned to consume 1 of 6 diets for 12 wk containing the same amount of total choline but differing in the forms of choline: 1-control low-fat (CLF, 20% fat, 100% free choline [FC]); 2-control high-fat (CHF, 50% fat, 100% FC); 3-100% PC (100PC, 50% fat, 100% egg-PC); 4-75% PC (75PC, 50% fat, 75% egg-PC+25% FC); 5-50% PC (50PC, 50% fat, 50% egg-PC+50% FC); and 6-25% PC (25PC; 50% fat, 25% egg-PC+75% FC). Intestinal permeability was measured by fluorescein isothiocyanate-dextran. Immune function was assessed by ex vivo cytokine production of splenocytes and cells isolated from the mesenteric lymph node (MLN) after stimulation with different mitogens. RESULTS: Feeding the CHF diet increased intestinal permeability compared with the CLF diet, and doses of PC 50% or greater returned permeability to levels similar to that of the CLF diet. Feeding the CHF diet lowered splenocyte production of interleukin (IL)-1ß, IL-2, IL-10, and tumor necrosis factor-alpha, and MLN production of IL-2 compared with the CLF group. The 50PC diet most consistently significantly improved cytokine levels (IL-2, IL-10, tumor necrosis factor-alpha) compared with the CHF diet. CONCLUSIONS: Our results show that a dose of 50% of total choline derived from egg-PC can ameliorate HFD-induced intestinal permeability and immune cell dysfunction.

Maternal diet supplementation with high-docosahexaenoic-acid canola oil, along with arachidonic acid, promotes immune system development in allergy-prone BALB/c mouse offspring at 3 weeks of age.

PURPOSE: To study the effects of feeding docosahexaenoic acid (DHA, derived from novel canola oil), with same amount of arachidonic acid (ARA), supplemented diet to lactating dams on the immune system development of suckled offspring using a T helper type-2 (Th2)-dominant BALB/c mouse. METHODS: Dams received nutritionally complete control (no ARA or DHA) or DHA + ARA diet (1% DHA and 1% ARA of total fatty acids) from 5 days pre-parturition to the end of 3-week suckling period. After euthanization, relevant tissues were collected to study fatty acids, splenocyte phenotype and function (ex vivo cytokines with/without lipopolysaccharide (LPS, bacterial challenge) or phorbol myristate acetate + ionomycin (PMAi) stimulation). RESULTS: Feeding dams a DHA diet significantly increased the mammary gland milk phospholipid concentration of DHA and ARA. This resulted in 60% higher DHA levels in splenocyte phospholipids of the pups although ARA levels showed no difference. In dams fed DHA diet, significantly higher proportion of CD27+ cytotoxic T cell (CTL) and CXCR3+ CCR6- Th (enriched in Th1) were observed than control, but there were no differences in the splenocyte function upon PMAi (non-specific lymphocyte stimulant) stimulation. Pups from DHA-fed dams showed significantly higher IL-1ß, IFN-γ and TNF-α (inflammatory cytokines) by LPS-stimulated splenocytes. This may be due to higher proportion of CD86+ macrophages and B cells (all p's < 0.05) in these pups, which may influence T cell polarization. CONCLUSION: Plant-based source of DHA in maternal diet resulted in higher ex vivo production of inflammatory cytokines by splenocytes due to change in their phenotype, and this can skew T cell towards Th1 response in a Th2-dominant BALB/c mouse.

Low-fat dairy consumption improves intestinal immune function more than high-fat dairy in a diet-induced swine model of insulin resistance.

PURPOSE: To understand the effects of consuming high-fat and low-fat dairy products on postprandial cardiometabolic risk factors and intestinal immune function, we used an established low birthweight (LBW) swine model of diet-induced insulin resistance. METHODS: LBW piglets were randomized to consume one of the 3 experimental high fat diets and were fed for a total of 7 weeks: (1) Control high fat (LBW-CHF), (2) CHF diet supplemented with 3 servings of high-fat dairy (LBW-HFDairy) and (3) CHF diet supplemented with 3 servings of low-fat dairy (LBW-LFDairy). As comparison groups, normal birthweight (NBW) piglets were fed a CHF (NBW-CHF) or standard pig grower diet (NBW-Chow). At 11 weeks of age, all piglets underwent an established modified oral glucose and fat tolerance test. At 12 weeks of age, piglets were euthanized and ex vivo cytokine production by cells isolated from mesenteric lymph node (MLN) stimulated with mitogens was assessed. RESULTS: Dairy consumption did not modulate postprandial plasma lipid, inflammatory markers and glucose concentrations. A lower production of IL-2 and TNF-α after pokeweed mitogen (PWM) stimulation was observed in LBW-CHF vs NBW-Chow (P < 0.05), suggesting impaired MLN T cell function. While feeding high-fat dairy had minimal effects, feeding low-fat dairy significantly improved the production of IL-2 and TNF-α after PWM stimulation (P < 0.05). CONCLUSIONS: Irrespective of fat content, dairy had a neutral effect on postprandial cardiometabolic risk factors. Low-fat dairy products improved intestinal T cell function to a greater extent than high-fat dairy in this swine model of obesity and insulin resistance.

The impact of protein source on serum potassium and phosphate levels in adults living with advanced kidney disease.

BACKGROUND AND AIMS: Plant proteins may be restricted on low potassium/phosphorus diets. The primary objective was to investigate the impact of protein source on serum potassium and phosphate levels in adults with stage 4-5 chronic kidney disease (CKD), including hemodialysis (HD). METHODS AND RESULTS: Using a cross-sectional design, 24-h recalls or food frequency questionnaires were used to assess dietary intake. Serum values were obtained from medical records. Quartiles (Q1-4) of plant:animal protein serving ratios was considered to investigate outcomes, with Q1 having high animal and low plant serving intake and those in Q4 having high plant and low animal servings. 216 participants were enrolled, 135 on HD and 81 stage 4/5 CKD. For both HD and CKD, there was no difference in either serum potassium or phosphate levels between those in Q4 consuming high plant:animal vs Q1 low plant:animal (for HD: potassium 4.6 mmol/L vs 4.6 mmol/L; phosphate 1.8 mmol/L vs 1.6 mmol/L, respectively; for CKD: potassium 4.7 mmol/L vs 4.6 mmol/L; phosphate 1.4 mmol/L vs 1.4 mmol/L; all p > 0.05). Those in Q4 consuming high plant:animal consumed 7.5 g (62%) more fibre than those in Q1 (low plant:animal). For diet quality, Q4 (high plant:animal) had a 12.8 point (24%) higher healthy eating index score than Q1 (low plant:animal). There was no relationship between plant:animal and serum albumin or hospital admissions (all p > 0.05). CONCLUSIONS: Consumption of higher proportions of plant protein was not associated with higher serum potassium or phosphate levels but was associated with higher fibre and diet quality.

Currently Available Handouts for Low Phosphorus Diets in Chronic Kidney Disease Continue to Restrict Plant Proteins and Minimally Processed Dairy Products.

OBJECTIVES: The 2020 Kidney Disease Outcome Quality Initiative guidelines recommend adjusting phosphorus intake to achieve and maintain normal serum phosphorus levels for adults living with chronic kidney disease. These guidelines also recommend considering the dietary source of phosphorus as different sources have different bioavailability; however, phosphorus food lists are not provided. Therefore, the aim of this study is to investigate the current teaching materials in Canada regarding low phosphorus diet. DESIGN AND METHODS: Using a geographical approach, websites from each province and territories' government, health, and renal programs (where applicable) were reviewed for resources on dietary phosphorus restriction in chronic kidney disease. All publicly available handouts/booklets/printable webpages were obtained and reviewed for recommendations on how to implement a low phosphorus diet. RESULTS: Sixty-one resources in total met inclusion criteria (52 handouts from health agencies in 6 provinces and 9 handouts from the Kidney Foundation of Canada). Items with minimal nutrition value, such as cola, beer and cocoa, chocolate, and baking powder, were the most commonly restricted with 84% (51/61) resources making this recommendation. Plant proteins and minimally processed dairy were restricted in 80% (49/61) of resources. Processed animal meat was recommended to be restricted in 70% (43/61) of resources and whole grains in 65% (40/61). Sixty-three percent of the handouts (39/61) discuss avoiding phosphorus additives. CONCLUSIONS: Many resources restrict items with minimal nutrition value to lower phosphorus intake; however, plant foods, including plant proteins and whole grains, continue to be restricted in the majority of resources, despite having lower bioavailability. The 2020 Kidney Disease Outcome Quality Initiative guidelines recommend considering bioavailability of phosphorus source when implementing low phosphorus diets; current handouts in Canada would likely benefit from review.

Phosphorus Additives and Their Impact on Phosphorus Content in Foods-An Analysis of the USDAs Branded Foods Product Database.

OBJECTIVES: The frequency of phosphate additives reported in the United States Department of Agriculture Branded Foods Product Database and how these additives impact phosphate content is unknown. METHODS: All products included in the Branded Foods Product Database reporting phosphorus content were reviewed for presence of phosphate salts and/or lecithin additives. RESULTS: Phosphorus content information was available for 3,466 (1.45%) food items, of these 1791 (51.6%) contained additives. Median phosphorus content was lowest in products with lecithin only compared to products without phosphorus additives (86 [54-200] vs. 145 [77-351] mg per 100 g, P < .01), which was not different from products with phosphate salts (176 [101-276] mg per 100 g, P = .22) or products with both phosphate salts and lecithin (161 [99-285] mg per 100 g, P = 1.00). The impact of a phosphorus salt on phosphorus content (mg per 100) was explored among ultra-processed products grouped by similar phosphorus contents. The phosphorus content of in in nondairy alternatives, dairy, plant proteins, and grains were significantly higher when the product contained a phosphate salt compared to products without a phosphate salt. For all products phosphorus and potassium content were correlated, but the relationship was stronger for when a potassium phosphate additive was present compared to absent (rho = 0.81 vs. 0.53, P < .05). Similar patterns were seen for sodium, calcium, and iron with stronger correlations with phosphate content for products with additives than those without (calcium phosphate: rho = 0.47 vs. 0.32; iron phosphate: rho = 0.47 vs. 0.33; sodium phosphate: rho = 0.45 vs. 0.07. All P < .05). The relationship between phosphate and sodium for products without phosphate additives was weak. CONCLUSIONS: Lecithin may not be associated with increased phosphorus content. Calcium, potassium, sodium, and iron phosphorus salts appear to be associated with increases in the composite mineral and phosphorus content, with the strongest correlation between potassium and phosphorus content.

Soaking to Reduce Potassium and Phosphorus Content of Foods.

OBJECTIVES: To achieve and maintain normal serum potassium and phosphorus levels reducing potassium and phosphorus intake is frequently recommended for adults living with chronic kidney disease. Exploring food preparation methods to reduce potassium and phosphorus content appears warranted. The study aim is to determine the impact of soaking foods in hot water on potassium and phosphorus content in a variety of plant- and animal-based foods. METHODS: Twenty foods were selected that are common staples in Brazilian diet patterns. Food was soaked for 5-10 minutes in deionized water that had been brought to a boil and then removed from heat using a 5-part water to 1-part sample ratio. The potassium content was determined by flame photometry. The phosphorus content was determined by visible ultraviolet spectrophotometry. RESULTS: Soaking foods resulted in a reduction in potassium and phosphorus. Potassium reduction in beef, green leafy vegetables, and grains was 40-49%; in chicken, fish, and nonleafy vegetables 30-39%; and tubers 10-20%. Phosphorus reduction in grains and beans was 30-39%; in nonleafy vegetables 20-29%; and beef, chicken, and fish 10-20%. CONCLUSIONS: Soaking foods in hot water for 5-10 minutes reduces potassium and phosphorus content. Using this technique to prepare foods may be a more acceptable alternative to longer demineralization periods making it easier for adults living with chronic kidney disease to follow diet recommendations.

Combined Supplementation with Arachidonic and Docosahexaenoic Acids in T Helper Type-2 Skewed Brown Norway Rat Offspring is Beneficial in the Induction of Oral Tolerance toward Ovalbumin and Immune System Development.

BACKGROUND: A T helper type-2 (Th2) skewed immune response is associated with food allergies. DHA and arachidonic acid (ARA) have been shown to promote oral tolerance (OT) in healthy rodents. OBJECTIVES: We studied the effect of combined ARA + DHA supplementation during the suckling and weaning periods on OT and immune system development in Th2-skewed Brown Norway rat offspring. METHODS: Dams were fed ARA + DHA (0.45% ARA, 0.8% DHA wt/wt of total fat; n = 10) as a suckling period diet (SPD) or control SPD (0% ARA, 0% DHA, n = 8). At 3 wk, offspring from each SPD group received ARA + DHA (0.5% ARA, 0.5% DHA wt/wt of total fat) weaning diet (WD), or control until 8 wk. For OT, offspring were orally exposed to either ovalbumin (OVA) or placebo between 21 and 25 d, followed by systemic immunization with OVA + adjuvant at 7 wk. Primary outcomes, ex vivo cytokine production by splenocytes and plasma OVA-specific Igs, were analyzed using a 3-way ANOVA. RESULTS: At 8 wk, despite no lasting effect of SPD on splenocytes fatty acids, ARA + DHA WD resulted in 2× higher DHA in splenocyte phospholipid compositions without affecting ARA. OT development was observed in OVA-exposed groups with 15% lower plasma OVA-IgE (P = 0.04) and 35% lower OVA-IgG1 (P = 0.01) than placebo. ARA + DHA SPD resulted in 35% lower OVA-IgG1 and iIL-6 (P = 0.04) when stimulated with LPS, and a higher proportion of mature B cells (OX12+, P = 0.0004, and IgG+, P = 0.008). ARA + DHA WD resulted in 20% higher Th1 cytokines (TNF-α and IFN-γ) production to lymphocyte stimulant and higher splenocyte proportion of CD45RA+ (pan-B cells) and OX6+ (dendritic cells) than control WD (P values < 0.05). CONCLUSIONS: Combined supplementation of ARA and DHA is beneficial for OT development, especially in the suckling period. Further, ARA + DHA supplementation can also counteract the Th2-skewed immunity of Brown Norway rat offspring through higher Th1 cytokine production by lymphocytes.

The Lipid-Soluble Forms of Choline Enhance Ex Vivo Responses from the Gut-Associated Immune System in Young Female Rat Offspring.

BACKGROUND: In humans, the development of gut-associated lymphoid tissue (GALT) occurs in the first years of life and can be influenced by diet. OBJECTIVES: The objective of this study was to determine the effect of dietary choline on the development of gut-associated lymphoid tissue (GALT). METHODS: Three feeding trials were conducted in female Sprague-Dawley rats. Beginning 3 d before parturition (studies 1 and 3) or at day 10 of gestation (study 2), control dams consumed a 100% free choline (FC) diet until the end of the lactation period. In studies 1 and 3, test dams consumed a high-glycerophosphocholine (HGPC) diet [75% glycerophosphocholine (GPC), 12.5% phosphatidylcholine (PC), 12.5% FC] and a 100% PC diet, respectively (both 1 g of choline/kg diet). In study 2, test dams consumed a high-sphingomyelin (SM) and PC (SMPC) diet (34% SM, 37% PC, 17% GPC, 7% FC, 5% phosphocholine) or a 50% PC diet (50% PC, 25% FC, 25% GPC), both 1.7 g of choline/kg diet. Immune cell phenotypes and ex vivo cytokine production by mitogen-stimulated immune cells were measured. RESULTS: Feeding of the HGPC diet lowered T-cell IL-2 (44%), IFN-γ (34%), and TNF-α (55%) production in mesenteric lymph nodes (MLNs) compared with control. Feeding both SMPC and 50% PC diets during the lactation and weaning periods increased IL-2 (54%) and TNF-α (46%) production after T-cell stimulation compared with control. There was a lower production of IL-2 (46%), IL-6 (66%), and TNF-α (45%), and a higher production of IL-10 (44%) in both SMPC and 50% PC groups following ovalbumin stimulation compared with control in MLNs. Feeding a diet containing 100% PC increased the production of IFN-γ by 52% after T-cell stimulation compared with control. CONCLUSION: Feeding a diet containing a mixture of choline forms with a high content of lipid-soluble forms during both the lactation and weaning periods enhances ex vivo immune responses from the GALT in female Sprague-Dawley offspring.

Sex Differences Distinctly Impact High-Fat Diet-Induced Immune Dysfunction in Wistar Rats.

BACKGROUND: Immune function is altered during obesity. Moreover, males and females across different species demonstrate distinct susceptibility to several diseases. However, less is known regarding the interplay between high-fat diet (HFD) and sex in the context of immune function. OBJECTIVES: The objective was to determine sex differences on immune function in response to an HFD compared with a control low-fat diet (LFD) in Wistar rats. METHODS: At 5 wk of age, male and female Wistar rats were randomly assigned to 1 of 2 diets for 9 wk: ad libitum control LFD (20 kcal% fat, 53 kcal% carbohydrate, and 27 kcal% protein) or HFD (50 kcal% fat, 23 kcal% carbohydrate, and 27 kcal% protein). At 13 wk of age, rats were killed and splenocytes were isolated. Immune cell subsets were determined by flow cytometry. Immune cell function was determined by measuring the ex vivo cytokine production following stimulation with mitogens. Two-factor ANOVA was used to assess the main effect of sex, diet, and their interaction. RESULTS: Males gained more weight than females (410 ± 46 vs. 219 ± 45 g), independently of diet (P-sex < 0.01). The HFD led to a lower production of IL-2 while increasing the production of IL-10 (both P-diet ≤ 0.05), independently of sex. HFD-fed females had increased production of cytokines (IL-2 and IL-6) after stimulation with phorbol 12-myristate 13-acetate plus ionomycin (PMA+I), as well as a higher T-helper (Th) 1:Th2 balance compared with HFD-fed males (all P < 0.05). Males fed the HFD had significantly lower production of IL-2 upon stimulation compared with all other groups. CONCLUSIONS: Female Wistar rats developed a milder obesity phenotype and maintained enhanced cytokine production compared with males fed the HFD. Sex differences modulate immune function in the context of high-fat feeding and it should be considered in research design to establish personalized health-related recommendations.

Comparison of diet quality tools to assess nutritional adequacy for adults living with kidney disease.

There is no specific diet quality tool recommended for adults living with chronic kidney disease (CKD). Identifying how diet quality tools assess nutritional adequacy and correlate with potassium and phosphorus (nutrients of interest in CKD) is warranted. Our aim was to compare Mediterranean Diet Scores (MDS), Healthy Eating Index (HEI), and Healthy Food Diversity (HFD) to determine their correlation with nutrient intake in adults living with diabetes and CKD. Using data from a longitudinal study of 50 participants with diabetes and CKD, diet quality was assessed at baseline and 1 or more times at annual visits up to 5 years (complete diet records n = 178). Diet quality was investigated for correlation with nutrient intake. Compared with HEI and HFD, MDS was poorly correlated with nutrient intake (all r values <0.40). HFD and HEI were moderately correlated with potassium (r = 0.66, P < 0.01 and r = 0.57, P < 0.01, respectively). HEI was weakly correlated with phosphorus (r = 0.365, P < 0.01). MDS recommends moderation of dairy and meat, this may have specific benefits for CKD as these are both sources of phosphorus, as such high MDS were associated with lower phosphorus intake. This study suggests that development of a renal specific diet quality assessment tool may be useful; however, further studies are needed.

Potassium content of the American food supply and implications for the management of hyperkalemia in dialysis: An analysis of the Branded Product Database.

Ultraprocessed foods can be a source of potassium additives. Excess potassium consumption can lead to hyperkalemia. How frequently potassium additives are found in the food supply and how they impact potassium content is not well documented. Using the Branded Product Database, ingredient lists were searched for "potassium" to identify products containing additives. For products listing potassium content, accuracy of potassium content reporting and how potassium content differed with additive use was also assessed. A total of 239,089 products were included, 35,102 (14.7%) contained potassium additives, and 13,685 (5.7%) provided potassium content. Potassium additives were most commonly found in dairy products, supplements, and mixed foods (at 37%, 34%, and 28%, respectively). Potassium additives in mixed foods and vegetables and fruits were associated with 71% and 28% more potassium per serving, respectively (p < 0.01). Potassium content increased by 1874 mg (66%) when a 1-day sample menu compared foods with and without additives. Potassium content of foods with and without additives is not well documented. Potassium additives are prevalent and can be associated with increased potassium content. However, more information is needed to better understand how different additives used in different foods change potassium content.

Buttermilk: an important source of lipid soluble forms of choline that influences the immune system development in Sprague-Dawley rat offspring.

PURPOSE: To determine the effect of feeding buttermilk-derived choline metabolites on the immune system development in Sprague-Dawley rat pups. METHODS: Sprague-Dawley dams were randomized to one of the three diets containing 1.7 g/kg choline: 1-Control (100% free choline (FC)), 2-Buttermilk (BM, 37% phosphatidylcholine (PC), 34% sphingomyelin (SM), 17% glycerophosphocholine (GPC), 7% FC, 5% phosphocholine), and 3-Placebo (PB, 50% PC, 25% FC, 25% GPC) until the end of the lactation period. At weaning, pups continued on the same diet as their mom. Cell phenotypes and cytokine production by mitogen-stimulated splenocytes isolated from 3- and 10-week-old pups were measured. RESULTS: At 3 weeks, BM-pups had a higher proportion of cytotoxic T cells (CTL; CD3 + CD8 +) while both BM- and PB-pups had an increased proportion of cells expressing CD28 + , CD86 + and CD27 + (all p > 0.05). Following ConA stimulation, splenocytes from BM- and PB-pups produced more TNF-α and IFN-γ and after LPS stimulation produced more IL-10 and TNF-α (all p > 0.05). Starting at week 6 of age, BM-pups had a higher body weight. At 10 weeks, both the BM- and PB-pups had a higher proportion of CTL expressing CD27 + . After ConA stimulation, splenocytes from BM- and PB-pups produced more IL-2, IFN-γ and IL-6 and more IL-10 after LPS stimulation (all p > 0.05). CONCLUSION: The proportion of lipid soluble forms of choline in the diet during lactation and weaning periods influence the immune system development in rat offspring.

Low Mediterranean Diet scores are associated with reduced kidney function and health related quality of life but not other markers of cardiovascular risk in adults with diabetes and chronic kidney disease.

BACKGROUND AND AIMS: How Mediterranean-style diets impact cardiovascular and health outcomes in patients with diabetes and chronic kidney disease (CKD) is not well known. Our aim was to investigate the association between diet quality, using Mediterranean Diet Scores (MDS) and health outcomes. METHODS AND RESULTS: This is a post-hoc analysis of an RCT and longitudinal study investigating patients with diabetes and CKD. MDS was calculated annually. Scores were analyzed for correlation with lipids, HbA1c, serum potassium, health-related quality of life (HRQOL) and depression. 178 diet records from 50 patients who attended two or more visits were included. Mean MDS was moderate (4.1 ± 1.6) and stable over time. Stage 1-2 vs 3-5 CKD had lower raw MDS (3.8 ± 1.5 vs 4.6 ± 1.5, p < 0.001). Having hyperkalemia was associated with a lower raw MDS scores (3.6 ± 1.6 vs 4.2 ± 1.5, p = 0.03) but not energy adjusted MDS. MDS was not associated with HbA1c or lipids. High vs low MDS was associated with improved HRQOL (mental health 84.4 ± 14.3 vs 80.3 ± 17.1, p < 0.05; general health 62.6 ± 21.0 vs 56.3 ± 19.8, p < 0.001) and fewer depressive symptoms (9.1 ± 7.4 vs 11.7 ± 10.6, p = 0.01). CONCLUSIONS: Low MDS was associated with reduced kidney function and health related quality of life, but not other markers of cardiovascular risk. Further studies are needed to understand the nature and direction of the association between diet quality and disease outcomes in this population.

Handouts for Low-Potassium Diets Disproportionately Restrict Fruits and Vegetables.

OBJECTIVE: Several recent publications, including an expert summary on hyperkalemia management, have encouraged plant-based foods for patients with chronic kidney disease (CKD) and highlighted the impact of potassium additives on total potassium intake. The aim of this research brief was to investigate if and/or how current recommendations for low-potassium diet may incorporate these new recommendations. DESIGN AND METHODS: Using a geographical approach, each province's and territory's government health and renal program (where applicable) website was reviewed for resources on dietary potassium restriction. All handouts/booklets/printable webpages were obtained and reviewed. RESULTS: Eighteen resources from 6 provincial health agencies in Canada were included. Six additional resources from national agencies were also included, 4 from Canada and 2 from the United States. The 5 most commonly restricted foods were bananas, potatoes, oranges, cantaloupe, and avocados. All resources recommended restriction of fruits and vegetables, 67% recommended restriction of dairy products, 57% recommended restriction of whole grain products, 62% recommended restrictions of plant-based proteins, and 67% mentioned restriction of other foods (such as coffee, tea, and chocolate), 28% mentioned restriction of potassium additives in ultraprocessed foods. CONCLUSION: Low-potassium diets primarily restrict fruits and vegetables while the least common restriction is ultraprocessed food. Several recent publics have recommended a greater focus on ultraprocessed versus unprocessed food for hyperkalemia management. These new recommendations differ from current teaching materials that predominately restrict plant-based foods to manage hyperkalemia in CKD. Updates will likely be needed to current resources to reflect new recommendations.

Feeding a Bioactive Oil Enriched in Stearidonic Acid during Early Life Influences Immune System Maturation in Neonatal Sprague-Dawley Rats.

BACKGROUND: Long-chain n-3 PUFAs (LCPUFAs) improve immune development and reduce atopic disease risk in infants. Stearidonic acid (SDA) can be a substrate for biosynthesis of n-3 LCPUFAs. OBJECTIVE: We aimed to determine the effect of feeding an SDA-enriched diet during suckling and weaning on offspring immunity and ability to develop oral tolerance (OT). METHODS: Pregnant Sprague-Dawley rats were randomly assigned to consume either SDA (3 g SDA/100 g fat) or a control (no SDA) diet, 5 d before parturition and through lactation (21 d). For the OT treatment, 10-d-old pups were fed ovalbumin (Ova; 200 µL of 8 mg/mL) or placebo daily for 5 d. At 21 d, pups (both sexes) were weaned to their respective maternal diet until 6 wk of age or killed. Systemic immunization was induced using Ova (in 3-wk-old pups) or Ova + adjuvant (in 6-wk-old pups). The effect of suckling diet (in 3-wk-old pups) or weaning diet (in 6-wk-old pups) and OT treatment on immune function (main outcome) in spleen and blood was compared using 2-factor ANOVA. RESULTS: An SDA-enriched maternal diet, compared with the control diet, resulted in higher plasma phospholipid (PL) EPA (15 times higher), docosapentaenoic acid (DPA; 3 times higher), and DHA (1.3 times higher) content in 3-wk-old pups, accompanied by higher B-cell function [plasma ovalbumin-specific IgG1 (Ova-IgG1), 2 times higher] ( P < 0.05). Compared with pups fed a control diet, the splenocytes from these pups had more (23%) helper T (Th) cells (CD3+CD4+) and activated (12%) Th cells (CD4+CD28+) (P < 0.02) than controls. At 6 wk, the SDA group had 30% more CD4+CD25+ splenocytes, and when stimulated ex vivo with LPS, produced less inflammatory IL-6 (50%) and TNF-α (30%) and more immunoregulatory IL-10 (45%) cytokines (P < 0.05) than the control group. The Ova-exposed group had less (30%) plasma Ova-IgG1 than the placebo group. Splenocytes and plasma PLs from the 6-wk-old SDA group had more EPA (2x) and DPA (3.5x) (P < 0.05), but not DHA, than the control group. CONCLUSIONS: Feeding SDA during lactation and weaning altered immune responses in directions believed to be beneficial.

Feeding Buttermilk-Derived Choline Forms During Gestation and Lactation Modulates Ex Vivo T-Cell Response in Rat Dams.

BACKGROUND: Buttermilk contains a mixture of choline forms; it is high in phosphatidylcholine (PC) and sphingomyelin (SM), which could have an impact on immune system development and function. OBJECTIVES: We aimed to determine the effect of feeding buttermilk-derived choline forms during pregnancy and lactation on maternal immune function. METHODS: Sprague Dawley dams (n = 8 per diet) were randomly assigned midway through pregnancy (10 d of gestation) to 1 of 3 experimental diets, containing 1.7 g/kg choline: control [100% free choline (FC)]; buttermilk [37% PC, 34% SM, 17% glycerophosphocholine (GPC), 7% FC, 5% phosphocholine]; or placebo (50% PC, 25% FC, 25% GPC). Dams consumed the same diet until the end of the lactation period (21 d after parturition). Cell phenotypes and cytokine production by mitogen-stimulated splenocytes were measured and compared using 1-factor ANOVA test in order to asses the effect of diet on immune fuction of lactating dams (main outcome). RESULTS: After ConA stimulation, splenocytes from dams in the buttermilk group produced more IL-2 (30%), TNF-α (30%), and IFN-γ (42%) compared with both the placebo and control diets. Placebo-fed dams had a higher proportion of CD8+ cells expressing CD152+ (22%) in spleen, and splenocytes from dams that were fed the buttermilk and the placebo diets produced about 50% and 53% more IL-10 after LPS and OVA stimulation, respectively, compared with the control group. CONCLUSIONS: Feeding buttermilk-derived choline forms during pregnancy and lactation had a beneficial impact on the immune system of Sprague Dawley rat dams, especially on T-cell function.